Patent Publication Number: US-9425332-B2

Title: Photosensor having emitter and receiver leads protruding from circuit-encapsulating portion to connect to light emitter and light receiver, respectively

Description:
FIELD 
     The present invention relates to a photosensor. 
     BACKGROUND 
     A photoelectric sensor known in the art is described in Patent Literature 1. The photosensor includes an emitter lead connected to a light emitter, a receiver lead connected to a light receiver, a circuit-encapsulating portion encapsulating an integrated circuit, and connecting terminals connected to external terminals. In this photosensor, the emitter lead and the receiver lead protrude from the circuit-encapsulating portion in a direction opposite to the direction in which the connecting terminals extend. 
     CITATION LIST 
     Patent Literature 
     Patent Literature 1: Japanese Unexamined Patent Application Publication No. 11-145505 
     SUMMARY 
     Technical Problem 
     Some designs of photosensors may include a receiver lead that protrudes from a circuit-encapsulating portion in a direction intersecting with the direction in which external connecting terminals extend. However, sensor modules known in the art have yet to achieve such designs in which the emitter and receiver leads protrude from the circuit-encapsulating portion in the direction intersecting with the direction in which the external connecting terminals extend. 
     To respond to this situation, it is an object of the present invention to provide a photosensor including a sensor module in which emitter and receiver leads protrude from a circuit-encapsulating portion in a direction intersecting with a direction in which external connecting terminals extend. 
     Solution to Problem 
     A first aspect of the invention provides a photosensor including a light emitter, a light receiver, a circuit-encapsulating portion, a connecting terminal, a first emitter lead, a second emitter lead, a first receiver lead, and a second receiver lead. The light receiver receives light from the light emitter and outputs a light receiving signal. The circuit-encapsulating portion encapsulates an integrated circuit that processes the light receiving signal. The connecting terminal protrudes from the circuit-encapsulating portion and connects to an external terminal. The first emitter lead and the second emitter lead are flat plates. The emitter leads connect the light emitter and the circuit-encapsulating portion. The first receiver lead and the second receiver lead are flat plates. The receiver leads connect the light receiver and the circuit-encapsulating portion. When a direction in which the connecting terminal extends is a first direction, and a plane parallel to the first direction is a first plane, the first emitter lead and the second emitter lead protrude from the circuit-encapsulating portion in a direction parallel to the first plane and intersecting with the first direction, and extend in a direction opposite to the first direction. The first receiver lead and the second receiver lead protrude from the circuit-encapsulating portion in a direction parallel to the first plane and intersecting with the first direction and opposite to a direction in which the first emitter lead and the second emitter lead protrude, and extend in the direction opposite to the first direction. The first emitter lead and the second emitter lead, and the first receiver lead and the second receiver lead are deformed to allow the light receiver and the light emitter to face each other. This achieves the sensor module structure in which the emitter and receiver leads protrude in the direction intersecting with the direction in which the connecting terminal extends. 
     The first emitter lead and the second emitter lead may be bent along a first bending line that is parallel to a second direction perpendicular to an optical axis of light. The first receiver lead and the second receiver lead may be bent along a second bending line that is parallel to the second direction. The simple processing allows the light emitter and the light receiver to face each other, and enables easy fabrication of the photosensor. 
     When the first emitter lead and the second emitter lead are unfolded in a plane without bending along the first bending line, the unfolded first emitter lead and the unfolded second emitter lead may extend across the first bending line. When the first receiver lead and the second receiver lead are unfolded in a plane without bending along the second bending line, the unfolded first receiver lead and the unfolded second receiver lead may extend across the second bending line. In this structure, the first emitter lead and the second emitter lead occupy both sides of the first bending line. Such leads provide areas to be pressed in the process of bending, and thus the first emitter lead and the second emitter lead can be bent easily. Likewise, the first receiver lead and the second receiver lead also occupy both sides of the second bending line and provide areas to be pressed in the process of bending, and thus the first and second receiver leads can be bent easily. 
     The first emitter lead may include a first emitter lead portion, a second emitter lead portion, a third emitter lead portion, and a fourth emitter lead portion. The first emitter lead portion protrudes from the circuit-encapsulating portion in a direction parallel to the first plane and intersecting with the first direction, and extends in a direction opposite to the first direction. The second emitter lead portion extends from the first emitter lead portion in one of an inward direction or an outward direction along an optical axis of the light. The third emitter lead portion is connected to the second emitter lead portion. The fourth emitter lead portion extends from the third emitter lead portion in the other one of the inward direction or the outward direction along the optical axis. The fourth emitter lead portion may include a first bending portion that is bent along the first bending line. The first receiver lead may include a first receiver lead portion, a second receiver lead portion, a third receiver lead portion, and a fourth receiver lead portion. The first receiver lead portion protrudes from the circuit-encapsulating portion in a direction parallel to the first plane and intersecting with the first direction, and extends in a direction opposite to a direction in which the first emitter lead and the second emitter lead protrude. The second receiver lead portion extends from the first receiver lead portion in one of an inward direction or an outward direction along the optical axis. The third receiver lead portion is connected to the second receiver lead portion. The fourth receiver lead portion extends from the third receiver lead portion in the other one of the inward direction or the outward direction. The fourth receiver lead portion includes a second bending portion bent along the second bending line. The first emitter lead can include the bending portion that allows the light emitter and the light receiver to face each other, without widening the first emitter lead in the direction intersecting with the first direction. Likewise, the first receiver lead can include the bending portion that allows the light emitter and the light receiver to face each other, without widening the first receiver lead. This structure increases the degree of freedom in designing the shape of the photosensor, and also uses less material for the leads. 
     An inner end of the second emitter lead portion may be located more inward than an outer end of the fourth emitter lead portion in a direction along the optical axis. An inner end of the fourth emitter lead portion may be located more inward than an outer end of the second emitter lead portion in the optical axis direction. An inner end of the second receiver lead portion may be located more inward than an outer end of the fourth receiver lead portion in the optical axis direction. An inner end of the fourth receiver lead portion may be located more inward than an outer end of the second receiver lead portion in the optical axis direction. This structure allows the fourth emitter lead portion and the fourth receiver lead portion to be long, and allows easy bending of the leads to arrange the light emitter and the light receiver facing each other. 
     The second emitter lead portion may extend inward from the first emitter lead portion in a direction along the optical axis. The fourth emitter lead portion may extend outward from the third emitter lead portion in the optical axis direction. The second receiver lead portion may extend inward from the first receiver lead portion in the optical axis direction. The fourth receiver lead portion may extend outward from the third receiver lead portion in the optical axis direction. This structure allows the fourth emitter lead portion and the fourth receiver lead portion to be long without widening the emitter lead and the receiver lead in a direction intersecting with the first direction, and allows easy bending for arranging the light emitter and the light receiver facing each other. 
     The second emitter lead may be located more inward than the first emitter lead in the optical axis direction. The second receiver lead may be located more inward than the first receiver lead in the optical axis direction. A distance between the second emitter lead and the third emitter lead portion in the optical axis direction may be smaller than a distance between the second emitter lead and the first emitter lead portion in the optical axis direction. A distance between the second receiver lead and the third receiver lead portion in the optical axis direction may be smaller than a distance between the second receiver lead and the first receiver lead portion in the optical axis direction. This structure allows the fourth emitter lead portion and the fourth receiver lead portion to be longer, and allows easier bending for arranging the light emitter and the light receiver facing each other. 
     The second emitter lead may include an inclined light emitting portion that is inclined to increase a distance thereof to the first emitter lead portion in the optical axis direction. The second receiver lead may include an inclined light receiving portion that is inclined to increase a distance thereof to the first receiver lead portion in the optical axis direction. This increases the distance for insulation between the first emitter lead and the second emitter lead, and achieves higher insulation between them. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front view of a photosensor according to one embodiment. 
         FIG. 2  is a top view of the photosensor according to the embodiment. 
         FIG. 3  is an exploded perspective view of the photosensor according to the embodiment. 
         FIG. 4  is a cross-sectional view of the photosensor taken along line IV-IV in  FIG. 2 . 
         FIG. 5  is a cross-sectional view of the photosensor taken along line V-V in  FIG. 1 . 
         FIG. 6  is a plan view of a sensor module according to the embodiment. 
         FIG. 7  is a plan view of a primary molded piece of the sensor module according to the embodiment. 
         FIG. 8  is a plan view of the detailed internal circuitry covered by resin in the sensor module shown in  FIG. 6 . 
         FIG. 9  is an enlarged view of an area including a protrusion. 
         FIG. 10  is a flowchart showing a method for manufacturing a sensor module according to the embodiment. 
         FIG. 11  is a flowchart showing another method for manufacturing a sensor module according to the embodiment. 
         FIGS. 12A and 12B  are side views of the sensor module shown in  FIG. 7 . 
         FIG. 13  is an enlarged view of a plurality of connecting terminals and their surrounding area. 
         FIG. 14  is an enlarged view of an area including a first inner terminal and a third inner terminal. 
         FIG. 15A  is a diagram showing a first inner terminal and a third inner terminal according to modifications of the embodiment. 
         FIG. 15B  is a diagram showing a first inner terminal and a third inner terminal according to modifications of the embodiment. 
         FIG. 16  is a plan view of a sensor module according to a modification. 
         FIG. 17  is a plan view of a primary molded piece of the sensor module according to the modification. 
         FIG. 18  is a side view of the sensor module including emitter and receiver leads bent into an L-shape as viewed in the optical axis direction. 
         FIGS. 19A to 19D  are detailed views of a subcase. 
         FIG. 20  is a front view of a photosensor according to another embodiment. 
         FIG. 21  is a top view of the photosensor according to the other embodiment. 
         FIG. 22  is an exploded perspective view of the photosensor according to the other embodiment. 
         FIG. 23  is a cross-sectional view of the photosensor taken along line XXIII-XXIII in  FIG. 21 . 
     
    
    
     DETAILED DESCRIPTION 
     An embodiment of the present invention will now be described with reference to the drawings. In the drawings referred to herein, the same numerals indicate the same or the corresponding components. 
       FIG. 1  is a front view of a photosensor  1 .  FIG. 2  is a top view of the photosensor  1 .  FIG. 3  is an exploded perspective view of the photosensor  1 . In  FIG. 3 , the photosensor  1  includes a sensor module  5 , a case  60 , a subcase  80 , and a bottom plate  98 . 
     As shown in  FIG. 1 , the case  60  includes a case body  61 , an emitter case section  62 , and a receiver case section  63 .  FIG. 4  is a cross-sectional view of the photosensor taken along line IV-IV in  FIG. 2 . In  FIG. 4 , the sensor module  5  is not sectioned. Referring to  FIG. 4 , the case body  61  accommodates a circuit-encapsulating portion  90 , which will be described below. The emitter case section  62  accommodates a light emitter  10 , a first emitter lead  20 , and a second emitter lead  22 , which will be described below. The receiver case section  63  accommodates a light receiver  15 , a first receiver lead  24 , and a second receiver lead  26 , which will be described below. The emitter case section  62  and the receiver case section  63  extend upward from the case body  61 .  FIG. 5  is a cross-sectional view of the photosensor taken along line V-V in  FIG. 1 . Referring to  FIG. 5 , the emitter case section  62  includes an emitter slit  66  on its surface facing the receiver case section  63 . The receiver case section  63  includes a receiver slit  67  on its surface facing the emitter case section  62 . 
     The present embodiment defines the directions as described below unless otherwise specified. The direction from the emitter slit  66  toward the receiver slit  67  is the right, and the direction opposite to this direction is the left. In the figures, the positive direction of X axis is the right. The right and the left correspond to the direction of an optical axis Ax of the light emitted from the light emitter  10  toward the light receiver  15  described below. The direction from the connecting terminals  50  toward the emitter and receiver case sections  62  and  63  is an upward direction, and the direction opposite to this direction is a downward direction. In the figures, the positive direction of Y axis is the upward direction. The direction from the center of the photosensor  1  toward the surface of the case  60  including an indicator lamp window  68  is the front, and the direction opposite to this direction is the back. In the figures, the positive direction of Z axis is the front. 
     The emitter case section  62  and the receiver case section  63  face each other. The photosensor  1  includes the pair of emitter and receiver slits  66  and  67  facing each other on an upper portion of the case  60 . The emitter case section  62  and the receiver case section  63  are spaced from each other in the direction of the optical axis Ax (X-axis direction). As shown in  FIGS. 1 and 2 , the case  60  includes mounting holes  69   a ,  69   b ,  69   c , and  69   d , which are formed through the case  60  in directions perpendicular to the direction in which the emitter and receiver slits  66  and  67  face each other (Y-axis and X-axis directions in  FIG. 1 ). 
     In the photosensor  1 , the sensor module  5  includes a plurality of connecting terminals  50 , which protrude outward from the bottom plate  98 . As shown in  FIG. 1 , the case  60  includes the square indicator lamp window  68  on its front surface. Through the indicator lamp window  68 , an operator can visually check an operation indicator lamp (hereafter referred to as an operation indicator  92 ). The operation indicator lamp illuminates under a predetermined condition, or specifically when a light receiving signal from the light receiver  15  exceeds a predetermined threshold or when the signal is below the threshold. The condition for turning on the operation indicator lamp will be described below. 
     As shown in  FIG. 3 , the subcase  80  and the sensor module  5  are placed into the case  60  in this order. The base plate  98 , which includes holes  99  through which the connecting terminals  50  are placed, is then attached to the bottom of the case  60 . 
       FIG. 6  is a plan view of the sensor module  5 .  FIG. 7  is a plan view of a primary molded piece of the sensor module  5 . In other words,  FIG. 7  is an unfolded view of the sensor module  5  in  FIG. 6 . The sensor module  5  unfolded in a plane shown in  FIG. 7  is hereafter referred to as a sensor module  4 .  FIG. 8  is a plan view of the detailed internal circuitry covered by resin in the sensor module  4  shown in  FIG. 6 . 
     Referring to  FIG. 6 , the sensor module  5  includes the light emitter  10 , the light receiver  15 , the first emitter lead  20 , the second emitter lead  22 , the first receiver lead  24 , the second receiver lead  26 , the integrated circuit  41 , the circuit-encapsulating portion  90 , and the connecting terminals  50 . The first emitter lead  20 , the second emitter lead  22 , the first receiver lead  24 , the second receiver lead  26 , and the connecting terminals  50  are hereafter collectively referred to as a leadframe  8 . The sensor module may be referred to as a photosensor component. The leadframe  8  includes conductive flat plates. In other words, the first emitter lead  20 , the second emitter lead  22 , the first receiver lead  24 , the second receiver lead  26 , and the connecting terminals  50  are the flat plates. 
     The light emitter  10  includes an emitter element  11  and an emitter encapsulating portion  12 . The emitter encapsulating portion  12  includes an emitter base  13  and an emitter lens  14 . In one example, the emitter element  11  is a light-emitting diode, although it may be another element. The emitter encapsulating portion  12  encapsulates the emitter element  11  with resin. The emitter base  13  covers the emitter element  11 . The emitter lens  14  has a curved surface, and protrudes from the emitter base  13 . The emitter lens  14  is circular as viewed in the direction of light being emitted. The emitter lens  14  collimates the light emitted from the emitter element  11 , and thus prevents the light from the emitter element  11  from diverging. 
     The light receiver  15  receives light from the light emitter  10 , and outputs a light receiving signal. The light receiver  15  includes a receiver element  16  and a receiver encapsulating portion  17 . The receiver encapsulating portion  17  includes a receiver base  18  and a receiver lens  19 . In one example, the receiver element  16  is a phototransistor, although it may be another element. The receiver element  16  and the emitter element  11  are arranged to face each other. More specifically, the photosensor  1  according to this embodiment is a transmissive photosensor that detects whether the receiver element  16  can directly receive light emitted from the emitter element  11 . The receiver encapsulating portion  17  encapsulates the receiver element  16  with resin. The receiver base  18  covers the receiver element  16 . The emitter lens  19  has a curved surface, and protrudes from the emitter base  18 . The emitter lens  19  is circular as viewed in the direction of light being received. The emitter lens  14  focuses light from the emitter element  11  onto the receiver element  16 . 
     Referring to  FIG. 8 , the emitter element  11  is mounted on the first emitter lead  20 . In other words, the emitter element  11  is mounted on the leadframe  8 . The receiver element  16  is mounted on the second receiver lead  26 . In other words, the receiver element  16  is mounted on the leadframe  8 . 
     The integrated circuit  41  is electrically connected to the emitter element  11  and the receiver element  16 . The integrated circuit  41  is mounted on a main lead  30 , which is a part of the leadframe  8 . The integrated circuit  41  is fixed to the leadframe  8  by, for example, die bonding, and is wired by wire bonding. In this manner, the integrated circuit  41  is mounted onto the leadframe  8 . The leadframe  8  thus includes the main lead  30 , and is connected to the integrated circuit  41 . The main lead  30 , which is to be encapsulated in the circuit-encapsulating portion described below, is a part of the leadframe  8  excluding the leads that function as the connecting terminals  50 . The leads that function as the connecting terminals  50  will be described below. 
     The first emitter lead  20  and the second emitter lead  22  connect the light emitter  10  and the circuit-encapsulating portion  90 . More specifically, the first emitter lead  20  connects the emitter element  11  and the main lead  30 . The second emitter lead  22  and a wire W 11  connect the emitter element  11  and the main lead  30 . The main lead  30  is connected to the integrated circuit  41  to connect the light emitter  10  to the integrated circuit  41  with the first and second emitter leads  20  and  22 . The downward direction (the direction in which the connecting terminals  50  extend, or the negative direction of Y axis) is referred to as a first direction. A plane parallel to the first direction is referred to as a first plane. The first plane is, for example, a plane defined by the surfaces of the connecting terminals  50  (XY plane). The first emitter lead  20  and the second emitter lead  22  extend from the circuit-encapsulating portion  90  in a direction parallel to the first plane and intersecting with the first direction (to the left, or in the negative direction of X axis). The first emitter lead  20  and the second emitter lead  22  extend in a direction opposite to the first direction (the positive direction of Y axis). 
     The first receiver lead  24  and the second receiver lead  26  connect the light receiver  15  and the circuit-encapsulating portion  90 . More specifically, the first receiver lead  24  and a wire W 12  connect the receiver element  16  and the main lead  30 . The main lead  30  is connected to the integrated circuit  41  to connect the light receiver  15  to the integrated circuit  41  with the first and second receiver leads  24  and  26 . As shown in  FIG. 6 , a plane perpendicular to the optical axis Ax of light emitted from the light emitter  10  toward the light receiver  15  and including the midpoint between the light emitter  10  and the light receiver  15  is referred to as a plane C 1 . In this case, the first receiver lead  24  and the second receiver lead  26  protrude from the circuit-encapsulating portion  90  in a direction parallel to the first plane and intersecting with the first direction. The first receiver lead  24  and the second receiver lead  26  extend in the direction opposite to the direction in which the first emitter lead  20  and the second emitter lead  22  extend (to the right, or in the positive direction of X axis). When, for example, the circuit-encapsulating portion  90  is a rectangular prism, the first receiver lead  24  and the second receiver lead  26  protrude from the surface of the circuit-encapsulating portion  90  facing the surface from which the first emitter lead  20  and the second emitter lead  22  protrude. These leads may protrude at any angles. The first and second receiver leads  24  and  26  protrude from the circuit-encapsulating portion  90  by a predetermined length and then bend, and extend in the direction opposite to the first direction (or the positive direction of Y axis). 
     As shown in  FIG. 6 , the first emitter lead  20  and the second emitter lead  22  and the first receiver lead  24  and the second receiver lead  26  in the sensor module  5  are bent and deformed to allow the light emitter  10  and the light receiver  15  to face each other. The light receiver  15  is arranged to face the light emitter  10 . In the example of  FIG. 6 , each of the first and second emitter leads  20  and  22  and the first and second receiver leads  24  and  26  is bent at a single point. Alternatively, the leads may be bent at a plurality of points, or may be twisted. The specific shapes and the bending characteristics of the first and second emitter leads  20  and  22  and the first and second receiver leads  24  and  26  will be described below. 
     The integrated circuit  41  includes, for example, an integrated circuit (IC) chip. The integrated circuit  41  applies a voltage to the gate of a transistor (not shown) connected to the emitter element  11  to allow a current to flow through the emitter element  11 , which then emits light. Through this process, the integrated circuit  41  controls light emission from the emitter element  11 . The integrated circuit  41  includes a current-voltage converter circuit, an amplifier circuit, and an A/D converter circuit (not shown). The integrated circuit  41  converts a photocurrent output from the receiver element  16  to a voltage, amplifies the voltage, and then determines the value of a light receiving signal, which is a digital value. The integrated circuit  41  also determines whether the receiver element  16  has received light by comparing the signal value with a predetermined threshold. This threshold is set based on the light receiving signals measured in a first case in which an object blocking light is detected between the light emitter  10  and the light receiver  15  and a second case in which no such object is detected between. The threshold allows the integrated circuit  41  to distinguish between the first case and the second case. The threshold is stored in, for example, an internal memory of the integrated circuit  41 . 
     The sensor modules  4  and  5  each include a light emitting element  42 , which illuminates the operation indicator  92 . The integrated circuit  41  is connected to the light emitting element  42  with the wire W 1 . The integrated circuit  41  controls the light emitting element  42  based on a result of determination for light reception. The light emitting element  42 , which is for example a light-emitting diode, is mounted on the main lead  30 . In other words, the light emitting element  42  is mounted on the leadframe  8 . The integrated circuit  41  and the light emitting element  42  are hereafter collectively referred to as a circuit block  40 . The integrated circuit  41  processes the light receiving signal transmitted from the light receiver  15 . Either when the value of the light receiving signal is not less than the threshold, or when the signal value is below the threshold, the integrated circuit  41  applies a control signal with a predetermined voltage to a transistor (not shown) connected to the light emitting element  42  to turn on the light emitting element  42 . The light emitting element  42  indicates the operation of the photosensor  1 , or specifically the result of the processing performed by the integrated circuit  41 . 
     In response to a light receiving signal from the light receiver  15 , the integrated circuit  41  performs either the first processing or the second processing described below.
     First Processing: When the value of the light receiving signal is not less than a predetermined threshold, the integrated circuit  41  outputs a control signal for turning on the light emitting element  42  (an ON signal, or for example a signal for outputting a power supply voltage Vcc). When the value of the light receiving signal is below the predetermined threshold, the integrated circuit  41  outputs a control signal for turning off the light emitting element  42  (an OFF signal, or for example a signal for outputting 0 V).   Second Processing: When the value of the light receiving signal is not less than a predetermined threshold, the integrated circuit  41  outputs a control signal for turning off the light emitting element  42  (an OFF signal). When the value of the light receiving signal is below the predetermined threshold, the integrated circuit  41  outputs a control signal for turning on the light emitting element  42  (an ON signal).
 
Switching Terminal
   

     The integrated circuit  41  switches between the first processing and the second processing in accordance with the voltage at a port P 1 . The voltage at the port P 1  differs depending on whether a protrusion  46  included in a power supply voltage wiring group  44  has been cut. Referring to  FIG. 8 , the power supply voltage wiring group  44  includes wires and leads for transmitting the power supply voltage Vcc to the port P 1 . The power supply voltage wiring group  44  includes wires W 2 , W 3 , and W 4 , the protrusion  46 , and a first lead  32  and a second lead  34 . The first lead  32  and the second lead  34  are parts of the main lead  30 . In other words, the main lead  30  includes the first lead  32  and the second lead  34 . When the protrusion  46  is connected to the first lead  32  and the second lead  34 , the protrusion  46  and the first lead  32  and the second lead  34  form a single lead. In other words, the leadframe  8  includes the protrusion  46 , the first lead  32 , and the second lead  34 . 
     The power supply voltage Vcc is applied to a power supply connecting terminal  51 , which is one of the connecting terminals  50 . The wires W 2  and W 3  connect the power supply connecting terminal  51  to the first lead  32 . The first lead  32  is connected to a port P 2  of the integrated circuit  41  with a wire W 13 . The protrusion  46  is connected to the first lead  32  and extends out of the circuit-encapsulating portion  90 . The protrusion  46  is connected to the second lead  34 . The wire W 4  connects the second lead  34  to the port P 1  of the integrated circuit  41 . When the protrusion  46  remains connected, the port P 1  receives the power supply voltage Vcc applied from the power supply connecting terminal  51  through the wires W 2  and W 3 , the first lead  32 , the protrusion  46 , the second lead  34 , and the wire W 4 . When the protrusion  46  has been cut, the second lead  34 , the wire W 4 , and the port P 1  enter an electrically floating state (with no electrical connection). In this case, a voltage other than the power supply voltage Vcc (for example, 0 V) is applied to the port P 1 . When the power supply voltage Vcc is applied to the port P 1 , the integrated circuit  41  performs one of the first processing or the second processing described above. When a voltage other than the power supply voltage Vcc is applied to the port P 1 , the integrated circuit  41  performs the other one of the first processing or the second processing. The figures other than  FIG. 8  each show the module from which the protrusion  46  has been removed. 
       FIG. 9  is an enlarged view of an area including the protrusion  46 . Referring to  FIG. 9 , the protrusion  46  includes a first protrusion  464 , a second protrusion  466 , and an external connector  460 . The first protrusion  464  connects to the first lead  32 . The second protrusion  466  connects to the second lead  34 . The first protrusion  464  and the second protrusion  466  protrude at different positions of the circuit-encapsulating portion  90 . The external connector  460  connects the first protrusion  464  to the second protrusion  466 . The external connector  460  extends from the first protrusion  464  in a direction different from the direction in which the first protrusion  464  protrudes. Likewise, the external connector  460  extends from the second protrusion  466  in a direction different from the direction in which the second protrusion  466  protrudes. 
     The first protrusion  464  and the first lead  32  may be collectively referred to as a first leadframe. The second protrusion  466  and the second lead  34  may be collectively referred to as a second leadframe. The sensor module  5  is fixed in either a first state where the first protrusion  464  and the second protrusion  466  are electrically connected, or a second state where the first protrusion  464  and the second protrusion  466  are electrically isolated. The sensor module  5  fixed in the first state performs one of the first processing or the second processing described above. The sensor module  5  fixed in the second state performs the other one of the first processing or the second processing. 
     The first protrusion  464  has a width D 1  in the direction perpendicular to the direction in which the first protrusion  464  protrudes. The second protrusion  466  has a width D 2  in the direction perpendicular to the direction in which the second protrusion  466  protrudes. The first protrusion  464  and the second protrusion  466  are spaced from each other by a distance D 3 , which is not less than the width D 1  and not less than the width D 2 , at an end surface of the circuit-encapsulating portion  90  from which the first and second protrusions  464  and  466  protrude. This structure prevents the first lead  32  and the second  34  from coming in contact with each other with burrs that can form when the protrusion  46  is cut and removed. 
     As shown in  FIG. 8 , the protrusion  46  is arranged between the first emitter lead  20  and the second emitter lead  22  on the first plane (XY plane) described above. The protrusion  46  may be arranged between the first receiver lead  24  and the second receiver lead  26  on the first plane (XY plane). This arrangement reduces the likelihood that the protrusion  46  can come in contact with the case  60  when the sensor module  5  is encased, and thus prevents the protrusion  46  from being disconnected accidentally when the sensor module  5  is encased. 
     As described above with reference to  FIG. 9 , the first processing and the second processing can be switched depending on whether the protrusion  46  is cut. Alternatively, the external connector  460  may be a conductive member separate from the first protrusion  464  and the second protrusion  466 . In this structure, the external connector  460  may be attached or detached to switch the processing of the sensor module  5  between the first processing and the second processing. The external connector  460 , which is a separate member from the first protrusion  464  and the second protrusion  466 , may be referred to as a connector chip. The connector chip is, for example, a rectangular member having a width not less than D 3 . 
     A method for manufacturing a sensor module using the protrusion  46  will now be described.  FIG. 10  is a flowchart showing a method of manufacturing the sensor module  4 . In step S 1 , an intermediate component for a first photosensor is prepared. The first photosensor intermediate component is a sensor module (a sensor component) including the protrusion  46  shown in  FIGS. 8 and 9  in the stage in which whether the protrusion  46  is to be cut has yet to be determined. In one example, the first photosensor intermediate component is prepared in the manner described below. The emitter element  11 , the receiver element  16 , the integrated circuit  41 , and the light emitting element  42  are first mounted onto the leadframe  8  by die bonding. The components are then connected to the leadframe by wire bonding. Subsequently, a resin-molding process is performed to form the light emitter  10 , the light receiver  15 , and the circuit-encapsulating portion  90 . Unnecessary portions of the leadframe  8  are then removed. The primary molded piece is released from the leadframe  8 , and burrs on the molded piece are removed. 
     After the processing in step S 1  completes, the manufacturer determines whether any part of the protrusion  46 , which includes the first protrusion  464 , the second protrusion  466 , and the external connector  460  of the first photosensor intermediate component, is to be cut (step S 2 ). When determining that the protrusion  46  is to be cut in step S 2  (Yes in step S 2 ), the manufacturer cuts the protrusion  46  (step S 3 ). When the protrusion  46  is determined not to be cut in step S 2  (No in step S 2 ), or when the processing in step S 3  is performed, the manufacturing processes end. 
     A method for manufacturing a sensor module using the connector chip that can connect the first protrusion  464  and the second protrusion  466  will now be described.  FIG. 11  is a flowchart showing a different method for manufacturing the sensor module  4 . In step S 11 , an intermediate component for a second photosensor is prepared. The second photosensor intermediate component differs from the first photosensor intermediate component in that its protrusion  46  consists of the first protrusion  464  and the second protrusion  466  and does not include the external connector  460 . The method for preparing the second photosensor intermediate component is substantially the same as the method described above for the first photosensor intermediate component. 
     When the processing in step S 11  completes, the manufacturer prepares a connector chip that can connect the first protrusion  464  and the second protrusion  466  (step S 12 ). The connector chip may be made of any conductive material. The manufacturer then determines whether the first protrusion  464  and the second protrusion  466  in the second photosensor intermediate component are to be connected (step S 13 ). When determining that the protrusions are to be connected in step S 13  (Yes in step S 13 ), the manufacturer connects the first protrusion  464  and the second protrusion  466  with the connector chip by, for example, soldering (step S 14 ). When the protrusions are determined not to be connected in step S 13  (No in step S 13 ), or when the processing in step S 14  is performed, the manufacturing processes end. 
     Resin for Circuit-Encapsulating Portion, Light Emitter, and Light Receiver 
     As shown in  FIGS. 6 to 8 , the circuit-encapsulating portion  90  encapsulates the circuit block  40 .  FIGS. 12A and 12B  are side views of the sensor module shown in  FIG. 7 .  FIG. 12A  is a left side view of the sensor module  4  shown in  FIG. 7 , and  FIG. 12B  is a right side view of the sensor module  4  shown in  FIG. 7 . In  FIGS. 12A and 12B , the dotted lines indicate the emitter element  11 , the receiver element  16 , and the light emitting element  42 . 
     Referring now to  FIGS. 7, 8, and 12A and 12B , the circuit-encapsulating portion  90  includes a circuit encapsulating body  91  and the operation indicator  92 . The circuit encapsulating body  91  encapsulates the circuit block  40 . More specifically, the circuit encapsulating body  91  encapsulates the integrated circuit  41  with resin. The circuit encapsulating body  91  further encapsulates the light emitting element  42  with resin. The operation indicator  92  is arranged on the circuit encapsulating body  91 . The operation indicator  92  faces the light emitting element  42 . In other words, the operation indicator  92  allows the light emitted from the light emitting element  42  to pass through it. 
     The emitter encapsulating portion  12 , the receiver encapsulating portion  17 , and the circuit-encapsulating portion  48  are formed from the same resin containing the same concentration of light diffusing agent. The emitter encapsulating portion  12 , the receiver encapsulating portion  17 , and the circuit-encapsulating portion  48  are connected to one another through the leadframe  8 . When the positive direction of Z axis is the upward direction in  FIG. 12A , the distance H 11  from the upper end of the emitter element  11  to the upper end of the emitter base  13  is smaller than the distance H 21  from the upper end of the light emitting element  42  to the upper end of the circuit encapsulating body  91 . The positive direction of Z axis also corresponds to the direction in which the emitter element  11  emits light and also corresponds to the direction in which the light emitting element  42  emits light. Thus, the thickness H 11  of the emitter base  13  in the direction in which the emitter element  11  emits light is smaller than the thickness H 21  of the circuit encapsulating body  91  in the direction in which the light emitting element  42  emits light. Additionally, when the positive direction of Z axis is the upward direction, the distance H 12  from the upper end of the emitter base  13  to the upper end (the rear nodal point) V 1  of the emitter lens  14  is smaller than the thickness H 22  of the operation indicator  92  in the Z-direction. The thickness H 12  of the emitter lens  19  in the direction in which the emitter element  11  emits light is smaller than the thickness H 22  of the operation indicator  92  in the direction in which the light emitting element  42  emits light. Thus, when the positive direction of Z axis is the upward direction, the distance H 1  from the upper end of the emitter element  11  to the upper end V 1  of the emitter lens  19  is smaller than the distance H 2  from the upper end of the light emitting element  42  to the upper end of the operation indicator  92 . In other words, the thickness H 1  of the emitter encapsulating portion  12  in the direction in which the emitter element  11  emits light is smaller than the thickness H 2  of the circuit-encapsulating portion  90  including the thickness of the operation indicator  92  in the direction in which the light emitting element  42  emits light. The distance H 2  is 1.5 times larger than the distance H 1 . 
     Referring to  FIG. 12B , when the positive direction of Z axis is the upward direction, the distance H 31  from the upper end of the receiver element  16  to the upper end of the receiver base  18  is smaller than the distance H 21  from the upper end of the light emitting element  42  to the upper end of the circuit encapsulating body  91 . The negative direction of Z axis also corresponds to the direction in which the receiver element  16  receives light, and the positive direction of Z axis also corresponds to the direction in which the light emitting element  42  emits light. Thus, the thickness H 31  of the receiver base  18  in the direction in which the receiver element  16  receives light is smaller than the thickness H 21  of the circuit encapsulating body  91  in the direction in which the light emitting element  42  emits light. Additionally, when the positive direction of Z axis is the upward direction, the distance H 32  from the upper end of the receiver base  18  to the upper end (the rear nodal point) V 2  of the receiver lens  19  is smaller than the thickness H 22  of the operation indicator  92  in the Z-direction. The thickness H 32  of the receiver lens  19  in the direction in which the receiver element  16  receives light is smaller than the thickness H 22  of the operation indicator  92  in the direction in which the light emitting element  42  emits light. Thus, when the positive direction of Z axis is the upward direction, the distance H 3  from the upper end of the receiver element  16  to the upper end (the rear nodal point) V 2  of the receiver lens  19  is smaller than the distance H 2  from the upper end of the light emitting element  42  to the upper end of the operation indicator  92 . In other words, the thickness H 3  of the receiver encapsulating portion  17  in the direction in which the receiver element  16  receives light is smaller than the thickness H 2  of the circuit-encapsulating portion  90  including the thickness of the operation indicator  92  in the direction in which the light emitting element  42  emits light. The distance H 2  is 1.5 times larger than the distance H 3 . 
     To increase the sensitivity of the photosensor  1 , the light emitted from the emitter element  11  and received by the receiver element  16  preferably has minimum diffusion, whereas the light emitted from the light emitting element  42  preferably has maximum diffusion to increase the visibility of an operator. The thickness H 1  of the emitter encapsulating portion  12  is smaller than the thickness H 2  of the circuit-encapsulating portion  90 . The thickness H 3  of the receiver encapsulating portion  17  is smaller than the thickness H 2  of the circuit-encapsulating portion  90 . This setting allows the emitter encapsulating portion  12  and the receiver encapsulating portion  17  to receive a lower degree of light diffusion and the circuit-encapsulating portion  90  to receive a higher degree of light diffusion, although the emitter encapsulating portion  12 , the receiver encapsulating portion  17 , and the circuit-encapsulating portion  48  are formed from the same resin containing the same concentration of light diffusing agent. 
     To diffuse light in the circuit-encapsulating portion  90  by a degree to achieve visibility, the resin may contain the light diffusing agent at a concentration of not less than 0.3% by weight. To obtain a photocurrent from the receiver element  16  without affecting the sensitivity of the photosensor  1 , the resin may contain the light diffusing agent at a concentration of not more than 0.7% by weight. Thus, the resin may preferably contain the light diffusing agent at a concentration ranging from 0.3 to 0.7% by weight. The resin may ideally contain the light diffusing agent at a concentration of 0.5% by weight. 
     Connecting Terminal 
     Referring to  FIG. 8 , the connecting terminals  50  include the power supply connecting terminal  51 , a ground (GND) terminal  54 , a first terminal  52 , and a third terminal  53 . The first terminal  52  and the third terminal  53  are collectively referred to as a first external connecting terminal. The first terminal  52  and the third terminal  53  protrude from the circuit-encapsulating portion  90 . In other words, the first external connecting terminal protrudes from the circuit-encapsulating portion  90 . The power supply connecting terminal  51  and the ground terminal  54  are collectively referred to as a second external connecting terminal. The power supply connecting terminal  51  and the ground terminal  54  protrude from the circuit-encapsulating portion  90 . In other words, the second external connecting terminal protrudes from the circuit-encapsulating portion  90 . 
       FIG. 13  is an enlarged view of the connecting terminals  50  and their surrounding area. Referring to  FIG. 13 , the first terminal  52  includes a first circuit connector  52   a , a first inner terminal  52   c , and a first outer terminal  52   d . The first circuit connector  52   a  is connected to the integrated circuit  41  with a wire W 5 . The first circuit connector  52   a  is a portion to which the wire W 5  is connected. The first circuit connector  52   a  is, for example, a rectangular lead shown in  FIG. 13 . The first circuit connector  52   a  may not be rectangular as in  FIG. 13 . 
     The first inner terminal  52   c  extends from the first circuit connector  52   a . More specifically, the first inner terminal  52   c  extends to the left (in the negative direction of X axis) and downward (in the negative direction of Y axis) from the first circuit connector  52   a . As shown in  FIG. 13 , the upper end of the first inner terminal  52   c  meets the first circuit connector  52   a . The lower end of the first inner terminal  52   c  is defined by a straight line including a lower distal end PE 1  of a first through-hole  523  and perpendicular to the direction in which the first outer terminal  52   d  extends (the negative direction of Y axis). The first inner terminal  52   c  may extend in a direction different from the direction shown in  FIG. 13 . The first inner terminal  52   c  may have any shape when the width of its portion in contact with the circuit-encapsulating portion  90  (the length in the direction perpendicular to the direction in which the first inner terminal  52   c  extends or to the negative direction of Y axis) is smaller than the width of its lower end (the length in the direction perpendicular to the direction in which the first inner terminal  52   c  extends or to the negative direction of Y axis). The shape of the first inner terminal  52   c  will be described in detail below. 
     The first outer terminal  52   d  extends from the first inner terminal  52   c . More specifically, the first outer terminal  52   d  extends downward (in the negative direction of Y axis) from the first inner terminal  52   c . The first outer terminal  52   d  includes a first end  52   b  opposite to its end connected to the first inner terminal  52   c . The first end  52   b  includes a second through-hole  525 , which is used for soldering. The dimension D 11  of the first outer terminal  52   d  in the direction perpendicular to the direction in which the first outer terminal  52   d  extends (X-axis direction) is uniform except for its curved portion around the first end  52   b.    
       FIG. 14  is an enlarged view of the first inner terminal  52   c . Referring to  FIG. 14 , the first inner terminal  52   c  includes a first portion  521 , a second portion  522 , and a third portion  524 . The first portion  521  includes a first left portion  1521  and a first right portion  2521 . The second portion  522  includes a second left portion  1522  and a second right portion  2522 . The first portion  521 , the second portion  522 , and the third portion  524  define a first through-hole  523 . In other words, the first inner terminal  52   c  includes the first through-hole  523 . 
     The first portion  521 , which is included in the first inner terminal  52   c , is located outside the circuit-encapsulating portion  90 . More specifically, the upper end of the first portion  521  is located where the first inner terminal  52   c  and the outline of the circuit-encapsulating portion  90  overlap as viewed in a direction perpendicular to the first plane (XY plane). The first left portion  1521  and the first right portion  2521  are located outside the circuit-encapsulating portion  90 . The first left portion  1521 , which is included in the first portion  521 , is located to the left of the first through-hole  523 . The first right portion  2521 , which is included in the first portion  521 , is located to the right of the first through-hole  523 . The first portion  521  is adjacent to the first outer terminal  52   d . In other words, the first left portion  1521  and the first right portion  2521  are adjacent to the first outer terminal  52   d.    
     The second portion  522  is adjacent to the first portion  521  and is located inside the circuit-encapsulating portion  90 . More specifically, the lower end of the second portion  522  is located where the first inner terminal  52   c  and the outline of the circuit-encapsulating portion  90  overlap as viewed in a direction perpendicular to the first plane (XY plane). The upper end of the second portion  522  is defined by a straight line including an upper distal end PE 3  of a first through-hole  523  as viewed in a direction perpendicular to the direction in which the first inner terminal  52   c  extends (the negative direction of Y axis). The second left portion  1522 , which is included in the second portion  522 , is located to the left of the first through-hole  523 . The second right portion  2522 , which is included in the second portion  522 , is located to the right of the first through-hole  523 . In other words, the second left portion  1522  is adjacent to the first left portion  1521  and is located inside the circuit-encapsulating portion  90 . The second right portion  2522  is adjacent to the first right portion  2521  and is located inside the circuit-encapsulating portion  90 . 
     The third portion  524  is located nearer the first circuit connector  52   a  than the second portion  522 . In other words, the third portion  524  is located nearer the first circuit connector  52   a  than the second left portion  1522  and the second right portion  2522 . More specifically, the upper end of the third portion  524  meets the first circuit connector  52   a . The lower end of the third portion  524  is defined by a straight line including an upper distal end PE 3  of the first through-hole  523  and perpendicular to the direction in which the first inner terminal  52   c  extends (the negative direction of Y axis). 
     The dimension D 12  of the first left portion  1521  in the direction perpendicular to the direction in which the first outer terminal  52   c  extends (X-axis direction) is smaller than the dimension D 11  of the first outer terminal  52   d  in the direction perpendicular to the direction in which the first outer terminal  52   d  extends (X-axis direction). Likewise, the dimension D 13  of the first right portion  2521  in the direction perpendicular to the first inner terminal  52   c  extends (X-axis direction) is smaller than the dimension D 11  of the first outer terminal  52   d  in the direction perpendicular to the direction in which the first outer terminal  52   d  extends (X-axis direction). The dimension of the first portion  521  in the direction perpendicular to the direction in which the first inner terminal  52   c  extends (X-axis direction) is D 12 +D 13 . The dimension D 12 +D 13  of the first portion  521  in the direction perpendicular to the direction in which the first inner terminal  52   c  extends (X-axis direction) is smaller than the dimension D 11  of the first outer terminal  52   d  in the direction perpendicular to the direction in which the first outer terminal  52   d  extends (X-axis direction). The first outer terminal  52   d  is soldered when the connecting terminals  50  are connected to an external circuit. When the first outer terminal  52   d  is soldered, the heat is transmitted toward the first circuit connector  52   a . With the dimension D 12 +D 13  of the first portion  521  being smaller than the dimension D 11  of the first outer terminal  52   d , less heat is transmitted toward the first circuit connector  52   a . This structure prevents the wire W 5  from being disconnected by heat. 
     The dimension D 14  of the second left portion  1522  in the direction perpendicular to the direction in which the first inner terminal  52   c  extends (X-axis direction) is smaller than the dimension D 12  of the first left portion  1521  in the direction perpendicular to the direction in which the first inner terminal  52   c  extends (X-axis direction). Likewise, the dimension D 15  of the second right portion  2522  in the direction perpendicular to the direction in which the first inner terminal  52   c  extends (X-axis direction) is smaller than the dimension D 13  of the first right portion  2521  in the direction perpendicular to the direction in which the first inner terminal  52   c  extends (X-axis direction). The dimension D 16  of the third portion  524  on its end meeting the second portion  522  in the direction perpendicular to the direction in which the first inner terminal  52   c  extends (X-axis direction) is larger than the dimension D 14  of the second left portion  1522  in the direction perpendicular to the direction in which the first inner terminal  52   c  extends (X-axis direction). Likewise, the dimension D 16  of the third portion  524  on its end meeting the second portion  522  in the direction perpendicular to the direction in which the first inner terminal  52   c  extends (X-axis direction) is larger than the dimension D 15  of the second right portion  2522  in the direction perpendicular to the direction in which the first inner terminal  52   c  extends (X-axis direction). The dimension of the second portion  522  in the direction perpendicular to the direction in which the first inner terminal  52   c  extends (X-axis direction) is D 14 +D 15 . The dimension D 16  of the third portion  524  on its end meeting the second portion  522  in the direction perpendicular to the direction in which the first inner terminal  52   c  extends (X-axis direction) is larger than the dimension D 14 +D 15  of the second portion  522  in the direction perpendicular to the direction in which the first inner terminal  52   c  extends (X-axis direction). When the first outer terminal  52   d  is soldered, the heat transmitted to the second portion  522  can melt the resin portion touching the second portion  522 . However, with the dimension D 16  of the third portion  524  on its end meeting the second portion  522  being larger than the dimension D 14 +D 15  of the second portion  522 , the first terminal  52  is less likely to detach from the circuit-encapsulating portion  90  if the resin portion touching the second portion  522  melts. 
     A portion of the first through-hole  523  is filled with the resin. The portion of the first through-hole  523  filled with the resin is referred to as a first hole encapsulator  93  (refer to  FIG. 8 ). The first hole encapsulator  93  partially encapsulates the first through-hole  523 . In other words, the first through-hole  523  has a portion not filled with resin. The circuit-encapsulating portion  90  is injection molded with the resin injected from an injection port (gate) G shown in  FIG. 8 . When the molding of the circuit-encapsulating portion  90  is complete, the gate G is removed, leaving a gate mark on the surface of the circuit-encapsulating portion  90  as an injection port corresponding portion  97 . The injection port corresponding portion  97  is thus at a position corresponding to the resin injection port G, through which resin is injected for injection-molding the circuit-encapsulating portion  90  with resin. As shown in  FIG. 8 , the first hole encapsulator  93  is located on one end of the circuit-encapsulating portion  90 , whereas the injection port corresponding portion  97  is located on the other end of the circuit-encapsulating portion  90 . This structure can generate more voids (bubbles) in the first through-hole  523 . If the dimension of the first portion  521  (D 12 +D 13 ) is large, the first external connecting terminal will trap air, which forms bubbles. The first portion  521  with the dimension (D 12 +D 13 ) smaller than the dimension D 11  of the first outer terminal  52   d  reduces the likelihood that air will be trapped by the first external connecting terminal. Additionally, reducing the terminal width (D 12 +D 13 ) reduces the area for trapping bubbles, and further reduces such bubbles causing insufficient resin filling. The first portion  521  may preferably be long enough in the direction in which the first inner terminal  52   c  extends to prevent burrs from forming in the process of injection-molding the circuit-encapsulating portion  90  with resin. 
     Referring to  FIG. 13 , the third terminal  53  includes a third circuit connector  53   a , a third inner terminal  53   c , and a third outer terminal  53   d . The third circuit connector  53   a  is connected to the integrated circuit  41  with a wire W 6 , a third lead  36 , which is a part of the main lead  30 , and wires W 7  and W 8 . The third circuit connector  53   a  is a portion to which the wire W 6  is connected. The third circuit connector  53   a  is, for example, a rectangular lead shown in  FIG. 13 . The third circuit connector  53   a  may not be rectangular as in  FIG. 13 . 
     The third inner terminal  53   c  extends from the third circuit connector  53   a . More specifically, the third inner terminal  53   c  extends downward (in the negative direction of Y axis) in a staggered manner on a plane from the third circuit connector  53   a . As shown in  FIG. 13 , the upper end of the third inner terminal  53   c  meets the third circuit connector  53   a . The lower end of the third inner terminal  53   c  is defined by a straight line including a lower distal end PE 2  of a third through-hole  533  perpendicular to the direction in which the third outer terminal  53   d  extends (in the negative direction of Y axis). The third inner terminal  53   c  may extend in a direction different from the direction shown in  FIG. 13 . The third inner terminal  53   c  may have any shape when the width of its portion in contact with the circuit-encapsulating portion  90  (the length in the direction perpendicular to the direction in which the third inner terminal  53   c  extends or to the negative direction of Y axis) is smaller than the width of its lower end (the length in the direction perpendicular to the direction in which the third inner terminal  53   c  extends or to the negative direction of Y axis). The shape of the third inner terminal  53   c  will be described in detail below. 
     The third outer terminal  53   d  extends from the third inner terminal  53   c . More specifically, the third outer terminal  53   d  extends downward (in the negative direction of Y axis) from the third inner terminal  53   c . The third outer terminal  53   d  includes a third end  53   b  opposite to its end connected to the third inner terminal  53   c . The third end  53   b  includes a fourth through-hole  535 , which is used for soldering. The dimension D 21  of the third outer terminal  53   d  in the direction perpendicular to the direction in which the third outer terminal  53   d  extends (X-axis direction) is uniform except for its curved portion around the third end  53   b.    
       FIG. 14  is an enlarged view of the third inner terminal  53   c . Referring to  FIG. 14 , the third inner terminal  53   c  includes a fourth portion  531 , a fifth portion  532 , and a sixth portion  534 . The fourth portion  531  includes a fourth left portion  1531  and a fourth right portion  2531 . The fifth portion  532  includes a fifth left portion  1532  and a fifth right portion  2532 . The fourth portion  531 , the fifth portion  532 , and the sixth portion  534  define a third through-hole  533 . In other words, the third inner terminal  53   c  includes the third through-hole  533 . 
     The fourth portion  531 , which is included in the third inner terminal  53   c , is located outside the circuit-encapsulating portion  90 . More specifically, the upper end of the fourth portion  531  is located where the third inner terminal  53   c  and the outline of the circuit-encapsulating portion  90  overlap as viewed in the direction perpendicular to the first plane (XY plane). The fourth left portion  1531  and the fourth right portion  2531  are located outside the circuit-encapsulating portion  90 . The fourth left portion  1531 , which is included in the fourth portion  531 , is located to the left of the third through-hole  533 . The fourth right portion  2531 , which is included in the fourth portion  531 , is located to the right of the third through-hole  533 . The fourth portion  531  is adjacent to the third outer terminal  53   d . In other words, the fourth left portion  1531  and the fourth right portion  2531  are adjacent to the third outer terminal  53   d.    
     The fifth portion  532  is adjacent to the fourth portion  531  and is located inside the circuit-encapsulating portion  90 . More specifically, the lower end of the fifth portion  532  is located where the third inner terminal  53   c  and the outline of the circuit-encapsulating portion  90  overlap as viewed in the direction perpendicular to the first plane (XY plane). The upper end of the fifth portion  532  is defined by a straight line including an upper distal end PE 4  of a third through-hole  533  as viewed in a direction perpendicular to the direction in which the third inner terminal  53   c  extends (the negative direction of Y axis). The fifth left portion  1532 , which is included in the fifth portion  532 , is located to the left of the third through-hole  533 . The fifth right portion  2532 , which is included in the fifth portion  532 , is located to the right of the third through-hole  533 . In other words, the fifth left portion  1532  is adjacent to the fourth left portion  1531  and is located inside the circuit-encapsulating portion  90 . The fifth right portion  2532  is adjacent to the fourth right portion  2531  and is located inside the circuit-encapsulating portion  90 . 
     The sixth portion  534  is located nearer the third circuit connector  53   a  than the fifth portion  532 . In other words, the sixth portion  534  is located nearer the third circuit connector  53   a  than the fifth left portion  1532  and the fifth right portion  2532 . More specifically, the upper end of the sixth portion  534  meets the third circuit connector  53   a . The lower end of the sixth portion  534  is defined by a straight line including the upper distal end PE 4  of the third through-hole  533  and perpendicular to the direction in which the third inner terminal  53   c  extends (to the negative direction of Y axis). 
     The dimension D 22  of the fourth left portion  1531  in the direction perpendicular to the direction in which the third outer terminal  53   c  extends (X-axis direction) is smaller than the dimension D 21  of the third outer terminal  53   d  in the direction perpendicular to the direction in which the third outer terminal  53   d  extends (X-axis direction). Likewise, the dimension D 23  of the fourth right portion  2531  in the direction perpendicular to the direction in which the third outer terminal  53   c  extends (X-axis direction) is smaller than the dimension D 21  of the third outer terminal  53   d  in the direction perpendicular to the direction in which the third outer terminal  53   d  extends (X-axis direction). The dimension of the fourth portion  531  in the direction perpendicular to the direction in which the third inner terminal  53   c  extends (X-axis direction) is D 22 +D 23 . The dimension D 22 +D 23  of the fourth portion  531  in the direction perpendicular to the direction in which the third inner terminal  53   c  extends (X-axis direction) is smaller than the dimension D 21  of the third outer terminal  53   d  in the direction perpendicular to the direction in which the third outer terminal  53   d  extends (X-axis direction). The third outer terminal  53   d  is soldered when the connecting terminals  50  are connected to an external circuit. When the third outer terminal  53   d  is soldered, the heat is transmitted toward the third circuit connector  53   a . With the dimension D 22 +D 23  of the fourth portion  531  being smaller than the dimension D 21  of the third outer terminal  53   d , less heat is transmitted toward the third circuit connector  53   a . This structure prevents the wires W 6  and W 7  from being disconnected by heat. 
     The dimension D 24  of the fifth left portion  1532  in the direction perpendicular to the direction in which the third inner terminal  53   c  extends (X-axis direction) is smaller than the dimension D 22  of the fourth left portion  1531  in the direction perpendicular to the direction in which the third inner terminal  53   c  extends (X-axis direction). Likewise, the dimension D 25  of the fifth right portion  2532  in the direction perpendicular to the direction in which the third inner terminal  53   c  extends (X-axis direction) is smaller than the dimension D 23  of the fourth right portion  2531  in the direction perpendicular to the direction in which the third inner terminal  53   c  extends (X-axis direction). The dimension D 26  of the sixth portion  534  in the direction perpendicular to the direction in which the third inner terminal  53   c  extends (X-axis direction) is larger than the dimension D 24  of the fifth left portion  1532  in the direction perpendicular to the direction in which the third inner terminal  53   c  extends (X-axis direction). The dimension D 26  of the sixth portion  534  in the direction perpendicular to the direction in which the third inner terminal  53   c  extends (X-axis direction) is larger than the dimension D 25  of the fifth right portion  2532  in the direction perpendicular to the direction in which the third inner terminal  53   c  extends (X-axis direction). The dimension of the fifth portion  532  in the direction perpendicular to the direction in which the third inner terminal  53   c  extends (X-axis direction) is D 24 +D 25 . The dimension D 26  of the sixth portion  534  in the direction perpendicular to the direction in which the third inner terminal  53   c  extends (X-axis direction) is larger than the dimension D 24 +D 25  of the fifth portion  532  in the direction perpendicular to the direction in which the third inner terminal  53   c  extends (X-axis direction). When the third outer terminal  53   d  is soldered, the heat transmitted to the fifth portion  532  can melt the resin portion touching the fifth portion  532 . However, with the dimension D 26  of the sixth portion  534  being larger than the dimension D 24 +D 25  of the fifth portion  532 , the third terminal  53  is less likely to be detached from the circuit-encapsulating portion  90  if the resin portion touching the fifth portion  532  melts. 
     A portion of the third through-hole  533  is filled with the resin. The portion of the third through-hole  533  filled with the resin is referred to as a third hole encapsulator  94  (refer to  FIG. 8 ). The third hole encapsulator  94  partially encapsulates the third through-hole  533 . In other words, the third through-hole  533  has a portion not filled with resin. The third hole encapsulator  94  is located on one end of the circuit-encapsulating portion  90 , whereas the injection port corresponding portion  97  is located on the other end of the circuit-encapsulating portion  90 . This structure can generate more voids (bubbles) in the third through-hole  533 . If the dimension of the fourth portion  531  (D 22 +D 23 ) is large, the first external connecting terminal will trap air, which forms bubbles. The fourth portion  531  with the dimension (D 22 +D 23 ) smaller than the dimension D 21  of the third outer terminal  53   d  reduces the likelihood that air will be trapped by the first external connecting terminal. Additionally, reducing the terminal width (D 22 +D 23 ) reduces the area for to trapping bubbles, and further reduces such bubbles causing insufficient resin filling. The fourth portion  531  may preferably be long enough in its direction in which the third inner terminal  53   c  extends to prevent burrs from forming in the process of injection-molding the circuit-encapsulating portion  90  with resin. 
     Referring to  FIG. 13 , the power supply terminal  51  includes a second circuit connector  51   a , a second inner terminal  51   c , and a second outer terminal  51   d . The second circuit connector  51   a  is connected to the integrated circuit  41  with the wires W 2  and W 3 , the second lead  34 , and the wire W 4 . The second inner terminal  51   c  extends from the second circuit connector  51   a . More specifically, the second inner terminal  51   c  extends to the left (in the negative direction of X axis) from the second circuit connector  51   a . The second outer terminal  51   d  extends from the second inner terminal  51   c . More specifically, the second outer terminal  51   d  extends downward (in the negative direction of Y axis) from the second inner terminal  51   c . The second outer terminal  51   d  includes a second end  54   b  opposite to its end connected to the fourth terminal  54   c . The second end  51   b  includes a fifth through-hole  515 , which is used for soldering. The dimension of the second outer terminal  51   d  in the direction perpendicular to the direction in which the second outer terminal  51   d  extends (X-axis direction) is substantially uniform. 
     The ground terminal  54  includes a fourth circuit connector  54   a , a fourth inner terminal  54   c , and a fourth outer terminal  54   d . The fourth circuit connector  54   a  is connected to the integrated circuit  41  with the first receiver lead  24  and a wire W 9 . The fourth inner terminal  54   c  extends from the fourth circuit connector  54   a . More specifically, the fourth inner terminal  54   c  extends downward (in the negative direction of Y axis) and to the right (the positive direction of X axis) from the fourth circuit connector  54   a . The fourth outer terminal  54   d  extends from the fourth inner terminal  54   c . More specifically, the fourth outer terminal  54   d  extends downward (in the negative direction of Y axis) from the fourth inner terminal  54   c . The fourth outer terminal  54   d  includes a fourth end  54   b  opposite to its end connected to the fourth terminal  54   c . The fourth end  54   b  includes a sixth through-hole  545 , which is used for soldering. The dimension of the fourth outer terminal  54   d  in the direction perpendicular to the direction in which the fourth outer terminal  54   d  extends (X-axis direction) is substantially uniform. 
     The distance between the second through-hole  525  and the first circuit connector  52   a  is smaller than the distance between the fifth through-hole  515  and the second circuit connector  51   a . Likewise, the distance between the fourth through-hole  535  and the third circuit connector  53   a  is smaller than the distance between the fifth through-hole  515  and the second circuit connector  51   a . Further, the distance between the second through-hole  525  and the first circuit connector  52   a  is smaller than the distance between the sixth through-hole  545  and the fourth circuit connector  54   a . Likewise, the distance between the fourth through-hole  535  and the third circuit connector  53   a  is smaller than the distance between the sixth through-hole  545  and the fourth circuit connector  54   a . The distance between the two parts does not refer to a distance on a straight line joining the two parts, but refers to the smallest distance on the lead joining the two parts. Each of the power supply terminal  51  and the ground terminal  54  has a long distance from its end to the circuit connector, and thus easily cools when heat is transmitted from the end to the circuit connector. In contrast, each of the first terminal  52  and the third terminal  53  has a small distance from its end to the circuit connector, and thus does not easily cool when heat is transmitted from the end to the circuit connector. To reduce heat transmission, the first terminal  52  has the first through-hole  523 , and the third terminal  53  has the third through-hole  533 . 
     The surface area of the first terminal  52  is smaller than the surface area of each of the power supply terminal  51  and the ground terminal  54 . The surface area of the third terminal  53  is smaller than the surface area of each of the power supply terminal  51  and the ground terminal  54 . Each of the power supply terminal  51  and the ground terminal  54  has a large surface area, and thus can cool easily when heat is transmitted from its end toward the circuit connector. In contrast, each of the first terminal  52  and the third terminal  53  has a small surface area, and thus does not cool easily when heat is transmitted from its end to the circuit connector. To reduce heat transmission, the first terminal  52  has the first through-hole  523 , and the third terminal  53  has the third through-hole  533 . 
     As described above, the first outer terminal  52   d  and the third outer terminal  53   d  extend in the same direction and have the same shape. The widths of the first inner terminal  52   c  and the third inner terminal  53   c  on their sides in contact with the circuit-encapsulating portion  90  are narrower than the widths of the first inner terminal  52   c  and the third inner terminal  53   c  on their lower ends. Thus, the first circuit connector  52   a  and the third circuit connector  53   a  may be replaced with each other. The first inner terminal  52   c  and the third inner terminal  53   c  may be replaced with each other. The first outer terminal  52   d  and the third outer terminal  53   d  may be replaced with each other. The first end  52   b  and the third end  53   b  may be replaced with each other. The first portion  521  and the fourth portion  531  may be replaced with each other. The second portion  522  and the fifth portion  532  may be replaced with each other. The third portion  524  and the sixth portion  534  may be replaced with each other. The first through-hole  523  and the third through-hole  533  may be replaced with each other. The first hole encapsulator  93  and the third hole encapsulator  94  may be replaced with each other. 
     Likewise, the second outer terminal  51   d  and the fourth outer terminal  54   d  extend in the same direction. Thus, the second circuit connector  51   a  and the fourth circuit connector  54   a  may be replaced with each other. The second inner terminal  51   c  and the fourth inner terminal  54   c  may be replaced with each other. The second outer terminal  51   d  and the fourth outer terminal  54   d  may be replaced with each other. 
     The first inner terminal  52   c  and the third inner terminal  53   c  may not have the through-holes  523  and  533 .  FIG. 15A  and  FIG. 15B  show first inner terminals and third inner terminals according to modifications of the present embodiment. As shown in  FIG. 15A (a), for example, a first terminal  152  includes a first inner terminal  152   c , a first circuit connector  52   a , and a first outer terminal  52   d . The first inner terminal  152   c  includes a first left portion  1521  and a second left portion  1522 . A third terminal  153  includes a third inner terminal  153   c , a third circuit connector  53   a , and a third outer terminal  53   d . The third inner terminal  153   c  includes a fourth left portion  1531  and a fifth left portion  1532 . As shown in  FIG. 15A (b), a first terminal  252  includes a first inner terminal  252   c , a first circuit connector  52   a , and a first outer terminal  52   d . The first terminal  252  includes a first right portion  2521  and a second right portion  2522 . A third terminal  253  includes a third inner terminal  253   c , a third circuit connector  53   a , and a third outer terminal  53   d . The third inner terminal  253   c  includes a fourth right portion  2531  and a fifth right portion  2532 . This structure also reduces the likelihood that air is trapped by the first external connecting terminal, and reduces insufficient resin filling. 
     In another example  FIG. 15B (c), a first terminal  352  includes a first inner terminal  352   c , a first circuit connector  52   a , and a first outer terminal  52   d . The first inner terminal  352   c  includes a first left portion  1521 , a second left portion  1522 , and a third portion  524 . A third terminal  353  includes a third inner terminal  353   c , a third circuit connector  53   a , and a third outer terminal  53   d . The third inner terminal  353   c  includes a fourth left portion  1531 , a fifth left portion  1532 , and a sixth portion  534 . In still another example shown in  FIG. 15B (d), a first terminal  452  includes a first inner terminal  452   c , a first circuit connector  52   a , and a first outer terminal  52   d . The first inner terminal  452   c  includes a first right portion  2521 , a second right portion  2522 , and a third portion  524 . A third terminal  453  includes a third inner terminal  453   c , a third circuit connector  53   a , and a third outer terminal  53   d . The third inner terminal  453   c  includes a fourth right portion  2531 , a fifth right portion  2532 , and a sixth portion  534 . These structures reduce the likelihood that air is trapped by the external connecting terminal and reduce insufficient resin filling, and further prevent the first terminals  352  and  452  and the third terminals  353  and  453  from easily detaching from the circuit-encapsulating portion  90  when the resin on the second portion or the fifth portion melts. 
     The photosensor of the present invention may include any of the first terminals  52 ,  152 ,  252 ,  352 , and  452  as its first terminal, and any of the third terminals  53 ,  153 ,  253 ,  353 , and  453  as its third terminal. 
     Emitter Lead and Receiver Lead 
     With the limited arrangement of pins of the integrated circuit  41  in the circuit-encapsulating portion  90 , the sensor module  5  includes the emitter leads  20  and  22  and the receiver leads  24  and  26  that protrude to the left and to the right. The sensor module  5  can be mounted on a flat (straight) type or an outer L-shaped type. The first emitter lead  20 , the second emitter lead  22 , the first receiver lead  24 , and the second receiver lead  26  have the characteristics described below. As shown in  FIG. 7 , the first emitter lead  20  includes a first emitter lead portion  202 , a second emitter lead portion  204 , a third emitter lead portion  206 , a fourth emitter lead portion  208 , and a fifth emitter lead portion  210 . 
     As shown in  FIG. 6 , the first emitter lead portion  202  protrudes in a direction parallel to the first plane (XY plane) described above and intersecting with the first direction described above (the negative direction of Y axis) from the circuit-encapsulating portion  90  and extends in a direction opposite to the first direction. More specifically, the first emitter lead portion  202  includes a first emitter lead protrusion  202   a , a first bending portion  202   c , and a first emitter lead extension  202   b . The first emitter lead protrusion  202   a  protrudes in the direction parallel to the first plane and intersecting with the first direction from the circuit-encapsulating portion  90 . The first bending portion  202   c  joins the first emitter lead protrusion  202   a  and the first emitter lead extension  202   b . The first emitter lead extension  202   b  extends from the first bending portion  202   c  to the first outer end  204   b  of the second emitter lead portion  204  in a direction opposite to the first direction (the positive direction of Y axis). The first emitter lead protrusion  202   a  is long enough (about 0.3 to 0.4 mm) to allow deburring after the process of injection-molding the circuit-encapsulating portion  90 . 
     The second emitter lead portion  204  includes a first outer end  204   b , a first inner end  204   a , and a first straight portion  204   c . The first outer end  204   b  joins the first emitter lead extension  202   b  and the first straight portion  204   c . The first outer end  204   b  is bent. The first straight portion  204   c  extends inward in the optical axis direction (X-axis direction) from the first outer end  204   b  to the first inner end  204   a . Being inward refers to being toward the plane C 1  described above in the optical axis direction (X-axis direction). Being outward refers to being away from the plane C 1  in the optical axis direction (X-axis direction). The first inner end  204   a  joins the first straight portion  204   c  and the third emitter lead portion  206 . The first inner end  204   a  is bent. The third emitter lead portion  206  is connected to the second emitter lead portion  204 . More specifically, the third emitter lead portion  206  extends in the direction opposite to the first direction (the positive direction of Y axis) from the first inner end  204   a  to a second inner end  208   a  (described later) of the fourth emitter lead portion  208 . 
     The fourth emitter lead portion  208  includes a second outer end  208   b , a second inner end  208   a , and a second straight portion  208   c . The second inner end  208   a  joins the third emitter lead portion  206  and the second straight portion  208   c . The second inner end  208   a  is bent. The second straight portion  208   c  extends outward in the optical axis direction (X-axis direction) from the second inner end  208   a  to the second outer end  208   b . Referring to  FIG. 7 , the fourth emitter lead portion  208  is bent at its first bending portion B 1  to allow the light emitter  10  and the light receiver  15  to face each other. As shown in  FIG. 6 , the fourth emitter lead portion  208  is bent at the first bending portion B 1  so that the first bending portion B 1  and the second outer end  208   b  overlap with each other as viewed in the direction perpendicular to the first plane (XY plane). As shown in  FIG. 6 , the first inner end  204   a  is located more inward than the second outer end  208   b  as viewed in the optical axis direction (X-axis direction). In the optical axis direction, the second inner end  208   a  is located more inward than the first outer end  204   b . This positional relationship results from the third emitter lead portion  206  arranged inward to allow the first bending portion B 1  to have a sufficient margin for bending in the fourth emitter lead portion  208 . 
     The second outer end  208   b  joins the second straight portion  208   c  and the fifth emitter lead portion  210 . The second outer end  208   b  is bent. The fifth emitter lead portion  210  is connected to the second outer end  208   b . The fifth emitter lead portion  210  bends and extends in the direction opposite to the first direction (the positive direction of Y axis) from the second outer end  208   b  to the light emitter  10 . 
     Referring to  FIGS. 6 and 7 , the second emitter lead  22  is located more inward than the first emitter lead  20  in the optical axis directions (X-axis direction). The second emitter lead  22  includes a sixth emitter lead  222 , a third bending portion  223 , a seventh emitter lead portion  224 , a fourth bending portion  225 , an eighth emitter lead portion  226 , a fifth bending portion  227 , a ninth emitter lead  228 , a sixth bending portion  229 , a tenth emitter lead portion  230 , a seventh bending portion  231 , an eleventh emitter lead  232 , an eighth bending portion  233 , and a twelfth emitter lead  234 . 
     The sixth emitter lead  222  protrudes in the direction parallel to the first plane (XY plane) and intersecting with the first direction (the negative direction of Y axis) from the circuit-encapsulating portion  90 , and extends in the direction opposite to the first direction. More specifically, the sixth emitter lead  222  includes a sixth emitter lead protrusion  222   a , a second bending portion  222   c , and a sixth emitter lead extension  222   b . The sixth emitter lead protrusion  222   a  protrudes in the direction parallel to the first plane and intersecting with the first direction from the circuit-encapsulating portion  90 . The second bending portion  222   c  joins the sixth emitter lead protrusion  222   a  and the sixth emitter lead extension  222   b . The sixth emitter lead extension  222   b  extends from the second bending portion  222   c  to the third bending portion  223  in the direction opposite to the first direction (the positive direction of Y axis). The sixth emitter lead protrusion  222   a  is long enough (about 0.3 to 0.4 mm) to allow deburring after the process of injection-molding the circuit-encapsulating portion  90 . As shown in  FIG. 6 , the distance D 1  between the second emitter lead  22  and the first emitter lead portion  202  (specifically, the distance D 1  between the sixth emitter lead extension  222   b  and the first emitter lead extension  202   b ) is set to prevent contact between and achieve insulation between the first emitter lead  20  and the second emitter lead  22 . 
     The third bending portion  223  joins the sixth emitter lead  222  and the seventh emitter lead portion  224 . The seventh emitter lead portion  224  extends in the direction opposite to the first direction (the negative direction of Y axis) and inward from the third bending portion  223  to the fourth bending portion  225 . The seventh emitter lead portion  224  corresponds to an inclined light emitting portion, which is inclined to increase its distance to the first emitter lead portion  202  in the optical axis direction. 
     The fourth bending portion  225  joins the seventh emitter lead portion  224  and the eighth emitter lead portion  226 . The eighth emitter lead portion  226  is connected to the seventh emitter lead portion  224 . More specifically, the eighth emitter lead portion  226  extends in the direction opposite to the first direction (the positive direction of Y axis) from the fourth bending portion  225  to the fifth bending portion  227 . As shown in  FIG. 6 , the distance D 2  between the second emitter lead  22  and the third emitter lead portion  206  (specifically, the distance D 2  between the eighth emitter lead portion  226  and the third emitter lead portion  206 ) is set to prevent contact between and achieve insulation between the first emitter lead  20  and the second emitter lead  22 . The distance D 2  between the second emitter lead  22  and the third emitter lead portion  206  is smaller than the distance D 1  between the second emitter lead  22  and the first emitter lead portion  202 . This results from the third emitter lead portion  206  arranged most inward to allow the first bending portion B 1  (described below) to have a sufficient margin for bending in the fourth emitter lead portion  208 . 
     The fifth bending portion  227  joins the eighth emitter lead portion  226  and the ninth emitter lead  228 . The ninth emitter lead  228  extends outward in the optical axis direction (X-axis direction) (in the direction opposite to the direction in which the seventh emitter lead portion  224  is inclined with respect to the optical axis direction, or the X-axis direction) from the fifth bending portion  227  to the sixth bending portion  229 . The sixth bending portion  229  joins the ninth emitter lead  228  and the tenth emitter lead portion  230 . The tenth emitter lead portion  230  is connected to the ninth emitter lead  228 . More specifically, the tenth emitter lead portion  230  extends from the sixth bending portion  229  to the seventh bending portion  231  in the direction opposite to the first direction (the positive direction of Y axis). The seventh bending portion  231  joins the tenth emitter lead portion  230  and the eleventh emitter lead  232 . The eleventh emitter lead  232  extends in the direction opposite to the first direction (the negative direction of Y axis) and inward from the seventh bending portion  231  to the eighth bending portion  233 . The eleventh emitter lead  232  is inclined to increase its distance to the first emitter lead  20  in the optical axis direction. The eighth bending portion  233  joins the eleventh emitter lead  232  and the twelfth emitter lead  234 . The twelfth emitter lead  234  is connected to the eighth bending portion  233  and extends in the direction opposite to the first direction (the positive direction of Y axis) to the light emitter  10 . 
     As shown in  FIGS. 6 and 7 , the first receiver lead  24  includes a first receiver lead portion  242 , a second receiver lead portion  244 , a third receiver lead portion  246 , a fourth receiver lead portion  248 , and a fifth receiver lead portion  250 . 
     As shown in  FIG. 6 , the first receiver lead portion  242  protrudes from the circuit-encapsulating portion  90  in the direction parallel to the first plane (XY plane) and intersecting with the first direction (the negative direction of Y axis) and in the direction opposite to the direction in which the first emitter lead  20  and the second emitter lead  22  protrude. More specifically, the first receiver lead portion  242  includes a first receiver lead protrusion  242   a , a ninth bending portion  242   c , and a first receiver extension  242   b . The first receiver lead protrusion  242   a  protrudes in the direction parallel to the first plane and intersecting with the first direction from the circuit-encapsulating portion  90  to the first bending portion  202   c . The first bending portion  202   c  joins the first receiver lead protrusion  242   a  and the first receiver lead protrusion  242   a . The first receiver extension  242   b  extends in the direction opposite to the first direction (the positive direction of Y axis) from the first bending portion  202   c  to the outer end  244   b  of the second receiver lead portion  244 . The sixth emitter lead protrusion  222   a  is long enough (about 0.3 to 0.4 mm) to allow deburring after the process of injection-molding the circuit-encapsulating portion  90 . 
     The second receiver lead portion  244  includes a third outer end  244   b , a third inner end  244   a , and a third straight portion  244   c . The third outer end  244   b  joins the first receiver extension  242   b  and the third straight portion  244   c . The third outer end  244   b  is bent. The third straight portion  244   c  extends inward in the optical axis direction (X-axis direction) from the third outer end  244   b  to the third inner end  244   a . The third inner end  244   a  joins the third straight portion  244   c  and the third receiver lead portion  246 . The third inner end  244   a  is bent. The third receiver lead portion  246  is connected to the second receiver lead portion  244 . More specifically, the third receiver lead portion  246  extends in the direction opposite to the first direction (the positive direction of Y axis) from the third inner end  244   a  to a fourth inner end  248   a  (described below) of the fourth receiver lead portion  248 . 
     The fourth receiver lead portion  248  includes a fourth outer end  248   b , a fourth inner end  248   a , and a fourth straight portion  248   c . The fourth inner end  248   a  joins the third receiver lead portion  246  and the fourth straight portion  248   c . The fourth inner end  248   a  is bent. The fourth straight portion  248   c  extends outward in the optical axis direction (X-axis direction) from the fourth inner end  248   a  to the fourth outer end  248   b . Referring to  FIG. 7 , the fourth receiver lead portion  248  is bent at its second bending portion B 2  to allow the light emitter  10  and the light receiver  15  to face each other. As shown in  FIG. 6 , the fourth receiver lead portion  248  is bent at the second bending portion B 2  so that the second bending portion B 2  and the fourth outer end  248   b  overlap with each other as viewed in the direction perpendicular to the first plane (XY plane). As shown in  FIG. 6 , the first inner end  244   a  of the second receiver portion  244  is located more inward than the fourth outer end  248   b  in the optical axis direction (X-axis direction). In the optical axis direction, the fourth inner end  248   a  is located more inward than the third outer end  244   b . This positional relationship results from the third receiver lead portion  246  arranged inward to allow the second bending portion B 2  to have a sufficient margin for bending in the fourth receiver lead portion  248 . 
     The fourth outer end  248   b  joins the fourth straight portion  248   c  and the fifth receiver lead portion  250 . The fourth outer end  248   b  is bent. The fifth receiver lead portion  250  is connected to the fourth outer end  248   b . The fifth receiver lead portion  250  bends and extends in the direction opposite to the first direction (the positive direction of Y axis) from the fourth outer end  248   b  to the light receiver  15 . 
     Referring to  FIGS. 6 and 7 , the second receiver lead  26  is located more inward than the first receiver lead  24  in the optical axis direction (X-axis direction). The second receiver lead  26  includes a sixth receiver lead portion  262 , an eleventh bending portion  263 , a seventh receiver lead portion  264 , a twelfth bending portion  265 , an eighth receiver lead portion  266 , a thirteenth bending portion  267 , a ninth receiver lead portion  268 , a fourteenth bending portion  269 , a tenth receiver lead portion  270 , a fifteenth bending portion  271 , an eleventh receiver lead portion  272 , a sixteenth bending portion  273 , and a twelfth receiver lead portion  274 . 
     The sixth receiver lead portion  262  protrudes from the circuit-encapsulating portion  90  in the direction parallel to the first plane (XY plane) and intersecting with the first direction (the negative direction of Y axis) and in the direction opposite to the direction in which the first emitter lead  20  and the second emitter lead  22  protrude, and in the direction opposite to the first direction. More specifically, the sixth receiver lead portion  262  includes a sixth receiver lead protrusion  262   a , a tenth bending portion  262   c , and a sixth receiver extension  262   b . The sixth receiver lead protrusion  262   a  protrudes from the circuit-encapsulating portion  90  in the direction parallel to the first plane and intersecting with the first direction and in the direction opposite to the direction in which the first emitter lead  20  and the second emitter lead  22  protrude. The tenth bending portion  262   c  joins the sixth receiver lead protrusion  262   a  and the sixth receiver extension  262   b . The sixth receiver extension  262   b  extends in the direction opposite to the first direction from the tenth bending portion  262   c  to the eleventh bending portion  263 . The sixth receiver lead protrusion  262   a  is long enough (about 0.3 to 0.4 mm) to allow deburring after the process of injection-molding the circuit-encapsulating portion  90 . As shown in  FIG. 6 , the distance D 3  between the second receiver lead  26  and the first receiver lead portion  242  (specifically, the distance D 3  between the sixth receiver extension  262   b  and the first receiver extension  242   b ) is set to prevent contact between and achieve insulation between the first emitter lead  20  and the second emitter lead  22 . 
     The eleventh bending portion  263  joins the sixth receiver lead portion  262  and the seventh receiver lead portion  264 . The seventh receiver lead portion  264  extends in the direction opposite to the first direction (the negative direction of Y axis) and inward from the eleventh bending portion  263  to the twelfth bending portion  265 . The seventh receiver lead portion  264  corresponds to an inclined light receiving portion, which is inclined to increase its distance to the sixth receiver lead portion  262  in the optical axis direction. 
     The twelfth bending portion  265  joins the seventh receiver lead portion  264  and the eighth receiver lead portion  266 . The eighth receiver lead portion  266  is connected to the seventh receiver lead portion  264 . More specifically, the eighth receiver lead portion  266  extends in the direction opposite to the first direction (the positive direction of Y axis) from the twelfth bending portion  265  to the thirteenth bending portion  267 . As shown in  FIG. 6 , the distance D 4  between the second receiver lead  26  and the third receiver lead portion  246  (specifically, the distance D 4  between the eighth receiver lead portion  266  and the third receiver lead portion  246 ) is set to prevent contact between and achieve insulation between the first receiver lead  20  and the second receiver lead  22 . The distance D 4  between the second receiver lead  26  and the third receiver lead portion  246  is smaller than the distance D 3  between the second receiver lead  26  and the first receiver lead portion  242 . This results from the third receiver lead portion  246  arranged most inward to allow the second bending portion B 2  (described below) to have a sufficient margin for bending in the fourth receiver lead portion  208 . 
     The thirteenth bending portion  267  joins the eighth receiver lead portion  266  and the ninth receiver lead portion  268 . The ninth receiver lead portion  268  extends outward in the optical axis direction (X-axis direction) (the direction opposite to the direction in which the seventh receiver lead portion  264  is inclined with respect to the optical axis direction or the X-axis direction) from the thirteenth bending portion  267  to the fourteenth bending portion  269 . The fourteenth bending portion  269  joins the ninth receiver lead portion  268  and the tenth receiver lead portion  270 . The tenth receiver lead portion  270  is connected to the ninth receiver lead portion  268 . More specifically, the tenth receiver lead portion  270  extends in the direction opposite to the first direction (the positive direction of Y axis) from the fourteenth bending portion  269  to the fifteenth bending portion  271 . The fifteenth bending portion  271  joins the tenth receiver lead portion  270  and the eleventh receiver lead portion  272 . The eleventh receiver lead portion  272  extends in the direction opposite to the first direction (the negative direction of Y axis) and inward from the fifteenth bending portion  271  to the sixteenth bending portion  273 . The eleventh receiver lead portion  272  is inclined to increase its distance to the first receiver lead  24  in the optical axis direction. The sixteenth bending portion  273  joins the eleventh receiver lead portion  272  and the twelfth receiver lead portion  274 . The twelfth receiver lead portion  274  is connected to the eighth bending portion  233 , and extends in the direction opposite to the first direction (the positive direction of Y axis) to the light emitter  10 . 
     To shape the primary molded piece (sensor module  4 ) of the sensor module  5  shown in  FIG. 7  into the structure shown in  FIG. 6  in which the light emitter  10  and the light receiver  15  face each other, the first emitter lead  20  and the second emitter lead  22  are bent along a first bending line L 1 . The first receiver lead  24  and the second receiver lead  26  are bent along a second bending line L 2 . The first bending line L 1  is parallel to a second direction (Y-axis direction) that is perpendicular to the optical axis. The second bending line L 2  is also parallel to the second direction (Y-axis direction). More specifically, the fourth emitter lead portion  208  includes the first bending portion B 1 , which is bent along the first bending line L 1 . The fourth receiver lead portion  248  includes the second bending portion B 2 , which is bent along the second bending line L 2 . The ninth emitter lead  228  includes the third bending portion B 3 , which is bent along the first bending line L 1 . The ninth receiver lead portion  268  includes a fourth bending portion B 4 , which is bent along the second bending line L 2 . 
     As shown in  FIG. 7 , when the first emitter lead  20  and the second emitter lead  22  are unfolded in a plane without bending along the first bending line L 1 , the unfolded first emitter lead  20  and the unfolded second emitter lead  22  extend across the first bending line L 1 . When the first receiver lead  24  and the second receiver lead  26  are unfolded in a plane without bending along the second bending line L 2 , the unfolded first receiver lead  24  and the unfolded second receiver lead  26  extend across the second bending line L 2 . 
     The first emitter lead  20 , the second emitter lead  22 , the first receiver lead  24 , and the second receiver lead  26  are wide enough (e.g., not less than 0.5 mm) to have strength to bend and also to support the light emitter  10  and the light receiver  15 . To have such strength, the first emitter lead  20 , the second emitter lead  22 , the first receiver lead  24 , and the second receiver lead  26  are preferably formed from a copper alloy, gold, silver, or a nickel alloy. The distance between the fifth emitter lead portion  210  and the eighth emitter lead portion  226  in the optical axis direction is smaller than the total of a vertical width D 31  and a horizontal width D 32  of the emitter case section  62  (refer to  FIG. 2 ). The distance between the fifth receiver lead portion  250  and the eighth receiver lead portion  266  in the optical axis direction is smaller than the total of a vertical width D 31  and a horizontal width D 33  of the receiver case section  63  (refer to  FIG. 2 ). This structure allows the emitter case section  62  and the receiver case section  63 , which satisfy the industry standards, to accommodate the emitter leads  20  and  22  and the receiver leads  24  and  26 . 
     The shapes of the first emitter lead  20 , the second emitter lead  22 , the first receiver lead  24 , and the second receiver lead  26  shown in  FIGS. 6 to 8  are mere examples. The first emitter lead  20 , the second emitter lead  22 , the first receiver lead  24 , and the second receiver lead  26  may be in any shapes that can satisfy the four conditions described below.
     Condition 1: For the unfolded first emitter lead  20  as shown in  FIG. 7 , the maximum distance between the first emitter lead  20  and the bending line L 1  in the X-axis direction (the distance between the fifth emitter lead portion  210  and the bending line L 1  in the X-axis direction) is smaller than the vertical width D 31  of the emitter case section  62  shown in  FIG. 2 .   Condition 2: For the unfolded second emitter lead  22  as shown in  FIG. 7 , the maximum distance between the second emitter lead  22  and the bending line L 1  in the X-axis direction (the distance between the eighth emitter lead portion  226  and the bending line L 1  in the X-axis direction) is smaller than the horizontal width D 32  of the emitter case section  62  shown in  FIG. 2 .   Condition 3: For the unfolded first receiver lead  24  as shown in  FIG. 7 , the maximum distance between the first receiver lead  24  and the bending line L 2  in the X-axis direction (the distance between the fifth receiver lead portion  250  and the bending line L 2  in the X-axis direction) is smaller than the vertical width D 31  of the receiver case section  63  shown in  FIG. 2 .   Condition 4: For the unfolded second receiver lead  26  as shown in  FIG. 7 , the maximum distance between the second receiver lead  26  and the bending line L 2  in the X-axis direction (the distance between the eighth receiver lead portion  266  and the bending line L 2  in the X-axis direction) is smaller than the horizontal width D 33  of the receiver case section  63  shown in  FIG. 2 .   

       FIG. 16  is a plan view of a sensor module  5   a  according to a modification.  FIG. 17  is a plan view of a primary molded piece of the sensor module  5   a  shown in  FIG. 16 . In other words,  FIG. 17  is an unfolded view of the sensor module  5   a  according to the modification in  FIG. 16 . The sensor module  5   a  unfolded in a plane shown in  FIG. 17  is hereafter referred to as a sensor module  4   a . In  FIGS. 16 and 17 , the components that are the same as the components shown in  FIGS. 6 and 7  are given the same reference numerals as those components and will not be described. 
     Referring to  FIGS. 16 and 17 , the sensor module  5   a  includes a first emitter lead  21 , a second emitter lead  23 , a first receiver lead  25 , and a second receiver lead  27 . The first emitter lead  21 , the second emitter lead  23 , the first receiver lead  25 , and the second receiver lead  27  are flat plates. The first emitter lead  21  and the second emitter lead  23  connect the light emitter  10  and the circuit-encapsulating portion  90 . The first emitter lead  21  and the second emitter lead  23  are parallel to the first plane (XY) described above and protrude in the direction intersecting with the first direction (to the left, or in the negative direction of X axis) from the circuit-encapsulating portion  90 . The first emitter lead  21  and the second emitter lead  23  extend in the direction opposite to the first direction (the positive direction of Y axis). The first receiver lead  25  and the second receiver lead  27  connect the light receiver  15  and the circuit-encapsulating portion  90 . The first receiver lead  25  and the second receiver lead  27  are parallel to the first plane and protrude in the direction intersecting with the first direction and in the direction opposite to the direction in which the first emitter lead  21  and the second emitter lead  23  protrude (to the right, or in the positive direction of X axis) from the circuit-encapsulating portion  90 . When, for example, the circuit-encapsulating portion  90  is a rectangular prism, the first and second receiver leads  25  and  27  protrude from the surface of the circuit-encapsulating portion  90  facing the surface from which the first and second receiver leads  21  and  23  protrude. These leads may protrude at any angles. The first and second emitter leads  25  and  27  extend in the direction opposite to the first direction (the positive direction of Y axis). The first and second emitter leads  21  and  23 , and the first and second receiver leads  25  and  27  are deformed to allow the light emitter  10  and the light receiver  15  to face each other. 
     As shown in  FIG. 16 , the first emitter lead  21  includes a first emitter lead portion  202 , a seventeenth emitter lead  205 , an eighteenth emitter lead portion  266   d , a thirteenth bending portion  267 , a nineteenth emitter lead portion  268   d , a fourteenth bending portion  269 , a twenty emitter lead portion  270   d , a fifteenth bending portion  271 , a twenty first emitter lead portion  272   d , a sixteenth bending portion  273 , and a twenty second emitter lead portion  274   d . The shapes of the components from the eighteenth emitter lead portion  266   d  to the twenty second emitter lead portion  274   d  are the same as the shapes of the corresponding components shown in  FIG. 7 , which are the components from the eighth receiver lead portion  266  to the eleventh receiver lead portion  272  in the figure. The first emitter lead portion  202  has the same shape as the first emitter lead portion  202  shown in  FIG. 7 . The first emitter lead portion  202  differs from the conventional emitter lead described above greatly in the seventeenth emitter lead  205 . The seventeenth emitter lead  205  will now be described. 
     The seventeenth emitter lead  205  includes a fifth outer end  205   b , a fifth inner end  205   a , and a fifth straight portion  205   c . The fifth inner end  205   a  joins the first emitter lead extension  202   b  and the fifth straight portion  204   g . The fifth inner end  205   a  is bent. The fifth straight portion  204   g  extends outward in the optical axis direction (X-axis direction) from the fifth inner end  205   a  to the fifth outer end  205   b . The fifth outer end  205   b  joins the fifth straight portion  205   c  and the eighteenth emitter lead portion  266   d . The fifth outer end  205   b  is bent. The eighteenth emitter lead portion  266   d  is connected to the seventeenth emitter lead  205 . More specifically, the eighteenth emitter lead portion  266   d  extends in the direction opposite to the first direction (the positive direction of Y axis) from the fifth outer end  205   b  to the thirteenth bending portion  267 . Referring to  FIG. 16 , the nineteenth emitter lead portion  268   d  extends inward in the optical axis direction (X-axis direction) from the thirteenth bending portion  267 . As shown in  FIG. 16 , the fifth inner end  205   a  is located more inward than the thirteenth bending portion  267  (corresponding to an outer end of the nineteenth emitter lead portion  268   d ) in the optical axis direction (X-axis direction). In the optical axis direction, the fourteenth bending portion  269  is located more inward than the fifth outer end  205   b  corresponding to an inner end of the nineteenth emitter lead portion  268   d . This positional relationship results from the eighteenth emitter lead portion  266   d  arranged outward to allow the first bending portion B 1  to have a sufficient margin for bending in the nineteenth emitter lead portion  268   d.    
     Referring to  FIGS. 16 and 17 , the second emitter lead  23  is located more inward than the first emitter lead  21  in the optical axis direction (X-axis direction). The second emitter lead  23  includes a sixth emitter lead  222 , a twenty third emitter lead portion  244   d , a twenty fourth emitter lead portion  246   d , a twenty fifth emitter lead portion  248   d , and a twenty sixth emitter lead portion  250   d . The shapes of the components from the twenty third emitter lead portion  244   d  to the twenty sixth emitter lead portion  250   d  are the same as the shapes of the corresponding components shown in  FIG. 7 , which are the components from the second receiver lead portion  244  to the fifth receiver lead portion  250  in the figure. The sixth emitter lead  222  has the same shape as the sixth emitter lead  222  shown in  FIG. 7 . 
     As shown in  FIG. 16 , the first receiver lead  24  includes a first receiver lead portion  242 , a seventeenth receiver lead  245 , an eighteenth receiver lead portion  226   d , a fifth bending portion  227 , a nineteenth receiver lead portion  228   d , a sixth bending portion  229 , a twenty receiver lead portion  230   d , a seventh bending portion  231 , a twenty first receiver lead  232   d , an eighth bending portion  233 , and a twenty second receiver lead  234   d . The shapes of the components from the eighteenth receiver lead portion  226   d  to the twenty second receiver lead  234   d  are the same as the shapes of the corresponding components shown in  FIG. 7 , which are the components from the eighth emitter lead portion  226  to the twelfth emitter lead  234  in the figure. The first receiver lead  24  differs from the conventional receiver lead described above greatly in the seventeenth receiver lead  245 . The seventeenth receiver lead  245  will now be described. 
     The seventeenth receiver lead  245  includes a sixth outer end  245   b , a sixth inner end  245   a , and a sixth straight portion  245   c . The sixth inner end  245   a  joins the first emitter lead extension  242   b  and the sixth straight portion  245   c . The sixth inner end  245   a  is bent. The sixth straight portion  245   c  extends outward in the optical axis direction (X-axis direction) from the sixth inner end  245   a  to the sixth outer end  245   b . The sixth outer end  245   b  joins the sixth straight portion  245   c  and the eighteenth receiver lead portion  226   d . The sixth outer end  245   b  is bent. The eighteenth receiver lead portion  226   d  is connected to the seventeenth receiver lead  245 . More specifically, the eighteenth receiver lead portion  226   d  extends in the direction opposite to the first direction (the positive direction of Y axis) from the sixth outer end  245   b  to the fifth bending portion  227 . The nineteenth receiver lead portion  228   d  extends inward in the optical axis direction (X-axis direction) from the fifth bending portion  227 . As shown in  FIG. 16 , the sixth inner end  245   a  is located more inward than the fifth bending portion  227  corresponding to an outer end the nineteenth receiver lead portion  228   d  in the optical axis direction (X-axis direction). In the optical axis direction, the sixth bending portion  229  corresponding to an inner end of the nineteenth receiver lead portion  228   d  is located more inward than the sixth outer end  245   b . This positional relationship results from the eighteenth receiver lead portion  226   d  arranged outward to allow the second bending portion B 2  to have a sufficient margin for bending in the nineteenth receiver lead portion  228   d.    
     Referring to  FIGS. 16 and 17 , the second receiver lead  27  is located more inward than the first receiver lead  25  in the optical axis direction (X-axis direction). The second receiver lead  27  includes a sixth receiver lead portion  262 , a twenty third receiver lead portion  204   d , a twenty fourth receiver lead portion  206   d , a twenty fifth receiver lead portion  208   d , and a twenty sixth receiver lead portion  210   d . The shapes of the components from the twenty third receiver lead portion  204   d  to the twenty sixth receiver lead portion  210   d  are the same as the shapes of the corresponding components shown in  FIG. 7 , which are the components from the second emitter lead portion  204  to the fifth emitter lead portion  210  the eighth emitter lead portion  226  to the twelfth emitter lead  234  in the figure. The sixth emitter lead portion  262  has the same shape as the sixth receiver lead portion  262  shown in  FIG. 7 . 
     To shape the primary molded piece (sensor module  4   a ) of the sensor module  5  shown in  FIG. 17  into the structure shown in  FIG. 16  in which the light emitter  10  and the light receiver  15  face each other, the first emitter lead  21  and the second emitter lead  22  are bent along a first bending line L 1 . The first receiver lead  25  and the second receiver lead  27  are bent along a second bending line L 2 . The first bending line L 1  is parallel to a second direction (Y-axis direction) that is perpendicular to the optical axis. The second bending line L 2  is also parallel to the second direction (Y-axis direction). More specifically, the nineteenth emitter lead portion  268   d  includes the first bending portion B 1 , which is bent along the first bending line L 1 . The nineteenth receiver lead portion  228   d  includes the second bending portion B 2 , which is bent along the second bending line L 2 . The twenty fifth emitter lead portion  248   d  includes a third bending portion B 3 , which is bent along the first bending line L 1 . The twenty fifth receiver lead portion  208   d  includes a fourth bending portion B 4 , which is bent along the second bending line L 2 . 
     As shown in  FIG. 17 , when the first emitter lead  21  and the second emitter lead  23  are unfolded in a plane without bending along the first bending line L 1 , the unfolded first emitter lead  21  and the unfolded second emitter lead  23  extend across the first bending line L 1 . When the first receiver lead  25  and the second receiver lead  27  are unfolded in a plane without bending along the second bending line L 2 , the unfolded first receiver lead  25  and the unfolded second receiver lead  27  extend across the second bending line L 2 . 
     The first emitter lead portion  202 , the sixth emitter lead  222 , the first receiver lead portion  242 , and the sixth receiver lead portion  262  have the same shapes. To allow deburring after the process of injection-molding the circuit-encapsulating portion  90 , the emitter leads  20  and  22  and the receiver leads  24  and  26  are arranged away from the circuit-encapsulating portion  90  by a distance of about 0.3 to 0.4 mm. As shown in  FIG. 16 , the distance between the first emitter lead  21  and the second emitter lead  23  is apparently larger than the distance D 2  in  FIG. 6 . The distance between the first emitter lead  21  and the second emitter lead  23  is set to prevent contact between and achieve insulation between them. Likewise, the distance between the first receiver lead  25  and the second receiver lead  27  is apparently larger than the distance D 4  in  FIG. 6 . The distance between the first receiver lead  25  and the second receiver lead  27  is set to prevent contact between and achieve insulation between them. The first emitter lead  21 , the second emitter lead  23 , the first receiver lead  25 , and the second receiver lead  27  are wide enough (e.g., not less than 0.5 mm) to have strength to bend and also to support the light emitter  10  and the light receiver  15 . To have such strength, the first emitter lead  21 , the second emitter lead  23 , the first receiver lead  25 , and the second receiver lead  27  are preferably formed from a copper alloy, gold, silver, or a nickel alloy. It is preferable that the first emitter lead  21 , the second emitter lead  23 , the first receiver lead  25 , and the second receiver lead  27  satisfy the conditions 1 to 4 described above. This structure achieves the sensor module  5  in which the emitter and receiver leads protrude from the side of the circuit-encapsulating portion  90 . 
     The sensor module  4  shown in  FIG. 7  changed to fit into an outer L-shaped type will now be described. Referring to  FIG. 7 , to change the module to fit into an outer L-shaped type, the first emitter lead  20 , the second emitter lead  22 , the first receiver lead  24 , and the second receiver lead  26  are bent not only along the bending lines L 1  and L 2  but also along third and fourth bending lines L 3  and L 4 .  FIG. 18  is a side view of the sensor module including emitter and receiver leads bent into an L-shape as viewed in the optical axis direction. Referring to  FIGS. 7 and 18 , the first emitter lead  20 , the second emitter lead  22 , the first receiver lead  24 , and the second receiver lead  26  are bent along the fourth bending line L 4  at an angle of 45 degrees with respect to the first plane (XY plane). The first emitter lead  20 , the second emitter lead  22 , the first receiver lead  24 , and the second receiver lead  26  include bending portions B 6 , B 8 , B 10 , and B 12 , which are bent along the fourth bending line L 4 . The first emitter lead  20 , the second emitter lead  22 , the first receiver lead  24 , and the second receiver lead  26  are bent along the third bending line L 3  at an angle of 45 degrees with respect to the first emitter lead  20 , the second emitter lead  22 , the first receiver lead  24 , and the second receiver lead  26 , which are bent along the fourth bending line L 4 . The first emitter lead  20 , the second emitter lead  22 , the first receiver lead  24 , and the second receiver lead  26  include bending portions B 5 , B 7 , B 9 , and B 11 , which are bent along the third bending line L 3 . More specifically, the first emitter lead  20 , the second emitter lead  22 , the first receiver lead  24 , and the second receiver lead  26  bent along the third bending line L 3  are perpendicular to the first plane (XY plane). The sensor module bent into an outer L-shaped type shown in  FIG. 18  will be hereafter referred to as a sensor module  6 . 
     A section including the bending portions B 5  and B 6 , a section including the bending portions B 7  and B 8 , a section including the bending portions B 9  and B 10 , and a section including the bending portions B 11  and B 12  are each referred to as a direction changing section. In particular, a section including the bending portions B 7  and B 8  of the second emitter lead  22  is referred to as a first direction changing section. A section including the bending portions B 11  and B 12  of the second receiver lead  26  is referred to as a second direction changing section. 
     The shape characteristics of the outer L-shaped type will now be described focusing on the second emitter lead  22  and the second receiver lead  26 . The sixth receiver lead portion  262  includes a sixth receiver lead protrusion  262   a , which extends from the circuit-encapsulating portion  90  in the optical axis direction (X-axis direction), and extends on the first plane (XY plane) described above from the circuit-encapsulating portion  90 . The sixth receiver lead portion  262  includes a sixth receiver extension  262   b , which extends on the first plane in the direction perpendicular to the optical axis direction (the positive direction of Y axis). This structure allows the second receiver lead  26  to protrude from the side surface of the circuit-encapsulating portion  90 , and thus the second receiver lead  26  can be bent along the bending line L 4 . The sixth receiver lead portion  262  may be referred to as a first receiver base lead, and the sixth receiver extension  262   b  may be referred to as a first receiver straight lead. 
     The eighth receiver lead portion  266  extends on a second plane (XZ plane) perpendicular to the first plane in the direction perpendicular to the optical axis direction (the positive direction in Z axis). The seventh receiver lead portion  264  joins the sixth receiver lead portion  262  and the eighth receiver lead portion  266 . The eighth receiver lead portion  266  may be referred to as a second receiver base lead, or as a second receiver straight lead. The seventh receiver lead portion  264  may be referred to as a receiver connection lead. 
     The sixth receiver extension  262   b  includes a bending portion B 12  that is bent along the fourth bending line L 4 . More specifically, the sixth receiver extension  262   b  is bent. The eighth receiver lead portion  266  includes a bending portion B 11  that is bent along the third bending line L 3 . The eighth receiver lead portion  266  is bent. The sixth receiver extension  262   b  and the eighth receiver lead portion  266  are both linear. Such lead portions are bent and thus allow easy bending. Referring to  FIG. 18 , the second receiver lead  26  is bent in the sixth receiver extension  262   b  at an angle of 45 degrees, and bent in the eighth receiver lead portion  266  at an angle of 45 degrees. The total angle by which the sixth receiver extension  262   b  is bent and the eighth receiver lead portion  266  is bent is 90 degrees. The second receiver lead  26  may not be bent at two positions each at an angle of 45 degrees as shown in  FIG. 18 , but may be bent at three or more points in a manner to achieve the total bending angle of 90 degrees. Alternatively, the second receiver lead  26  may be bent in a curve so that the unbent surface and the bent surface form an angle of 90 degrees. 
     The second receiver lead  26  extends from its third base S 3 , which is on the surface of the circuit-encapsulating portion  90 , to its fourth base S 4 , which is on the surface of the light emitter  10 . The second receiver lead  26  includes a second direction changing section between the third base S 3  and the fourth base S 4 . The second direction changing section changes the direction in which the second receiver lead  26  extends from the first plane (XY plane) to the direction perpendicular to the first plane. The second receiver lead  26  is bent at multiple points between the third base S 3  and the fourth base S 4 . Referring to  FIG. 18 , the length of the second receiver lead  26  from the third base S 3  and the second direction changing section to the fourth base S 4  as viewed in the optical axis direction (X-axis direction) is defined by the total of a straight-line distance D 31  from the third base S 3  to the second direction changing section (bending portion B 12 ) viewed in the optical axis direction (X-axis direction), a straight-line distance D 32  from the second direction changing section (bending portion B 11 ) to the fourth base S 4  viewed in the optical axis direction, and a straight-line distance D 33  between one end of the second direction changing section in contact with a portion of the second receiver lead  26  extending from the third base S 3  and the other end of the second direction changing section in contact with a portion of the second receiver lead  26  extending to the fourth base S 4  viewed in the optical axis direction. The length of the second receiver lead  26  extending from the third base S 3  and the second direction changing section to the fourth base S 4  as viewed in the optical axis direction is smaller than the length (D 41 +D 42 ) of an L-shaped second virtual lead  26   v  (indicted by a chain double-dashed line in  FIG. 18 ) that is bent at one point by 90 degrees between the third base S 3  and the fourth base S 4  viewed in the optical axis direction. 
     Referring to  FIG. 7 , the sixth emitter lead  222  includes a sixth emitter lead protrusion  222   a , which extends from the circuit-encapsulating portion  90  in the optical axis direction (X-axis direction), and extends on the first plane (XY plane) from the circuit-encapsulating portion  90 . The sixth emitter lead  222  includes a sixth emitter lead extension  222   b , which extends on the first plane in the direction perpendicular to the optical axis direction (the positive direction of Y axis). This structure allows the second emitter lead  22  to protrude from the side surface of the circuit-encapsulating portion  90 , and thus the second emitter lead  22  can be bent along the bending line L 4 . The sixth emitter lead  222  may be referred to as a first emitter base lead, and the sixth emitter lead extension  222   b  may be referred to as a first emitter straight lead. 
     The eighth emitter lead portion  226  extends on a second plane (XZ plane) perpendicular to the first plane in the direction perpendicular to the optical axis direction (the positive direction in Z axis). The seventh emitter lead portion  224  connects the sixth emitter lead  222  and the eighth emitter lead portion  226 . The eighth emitter lead portion  226  may be referred to as a second emitter base lead, or as a second emitter straight lead. The seventh emitter lead portion  224  may be referred to as an emitter connection lead. 
     The sixth emitter lead extension  222   b  includes a bending portion B 8  that is bent along the fourth bending line L 4 . More specifically, the sixth emitter lead extension  222   b  is bent. The eighth emitter lead portion  226  includes a bending portion B 7  that is bent along the third bending line L 3 . The eighth emitter lead portion  226  is bent. The sixth emitter lead extension  222   b  and the eighth emitter lead portion  226  are both linear. Such lead portions are bent and thus allow easy bending. The second emitter lead  22  is bent in the sixth emitter lead extension  222   b  at an angle of 45 degrees, and bent in the eighth emitter lead portion  226  at an angle of 45 degrees. The total angle by which the sixth emitter lead extension  222   b  is bent and the eighth emitter lead portion  226  is bent is 90 degrees. The second emitter lead  22  may not be bent at two points each at an angle of 45 degrees as shown in  FIG. 18 , but may be bent at three or more points in a manner to achieve the total bending angle of 90 degrees. Alternatively, the second emitter lead  22  may be bent in a curve so that the unbent surface and the bent surface form an angle of 90 degrees. 
     The second emitter lead  22  extends from its first base S 1 , which is on the surface of the circuit-encapsulating portion  90 , to its second base S 2  (refer to  FIG. 7 ), which is on the surface of the light emitter  10 . The second emitter lead  22  includes a second direction changing section between the first base S 1  and the second base S 2 . The second direction changing direction changes the direction in which the second emitter lead  22  extends from the first plane (XY plane) to the direction perpendicular to the first plane. The second emitter lead  22  is bent at multiple points between the first base and the second base. The length of the second emitter lead  22  from the first base S 1  and the first direction changing section to the second base S 2  as viewed in the optical axis direction (X-axis direction) is defined by the total of a straight-line distance from the first base S 1  to the first direction changing section (bending portion B 6 ) viewed in the optical axis direction (X-axis direction), a straight-line distance from the first direction changing section (bending portion B 6 ) to the second base S 2  viewed in the optical axis direction, and a straight-line distance between one end of the first direction changing section in contact with a portion of the second emitter lead  22  extending from the first base S 1  and the other end of the first direction changing section in contact with a portion of the second emitter lead  22  extending to the second base S 2  viewed in the optical axis direction. The length of the second emitter lead  22  extending from the first base S 1  and the first direction changing section to the second base S 2  as viewed in the optical axis direction is smaller than the length (D 41 +D 42 ) of an L-shaped first virtual lead bent at one point by 90 degrees between the first base S 1  and the second base S 2  viewed in the optical axis direction. This allows the single sensor module  4  to be bent to fit into a flat (straight) type or an outer L-shaped type.  FIG. 18  is a left side view of the sensor module, and does not show the second emitter lead  22 . As described above, the second emitter lead  22  is symmetric to the second receiver lead  26  with respect to the plane C 1  (refer to  FIG. 6 ). Thus, the second emitter lead  22  is bent in the same manner as shown in  FIG. 18 . Further, the first virtual lead has the same shape as the second virtual lead  26   v.    
     In this manner, bending the first emitter lead  20 , the second emitter lead  22 , the first receiver lead  24 , and the second receiver lead  26  enables the free setting of the Z-axis distance between the light emitter  10  and the circuit-encapsulating portion  90 , and the Z-axis distance between the light receiver  15  and the circuit-encapsulating portion  90 . This increases the degree of freedom in designing the outer shape of the photosensor  1  (optical axis Ax). 
     Case for Sensor Module 
     A case for encasing the sensor module  5  will now be described. When the sensor module  5  is placed in the case  60 , the subcase  80  is also used. The subcase  80  guides the light emitter  10  and the light receiver  15  when the sensor module  5  is placed into the case  60 , and prevents the first emitter lead  20 , the second emitter lead  22 , the first receiver lead  24 , and the second receiver lead  26  from coming in contact with the inner wall of the case  60  and being deformed.  FIG. 19A  is a front view of the subcase  80 .  FIG. 19B  is a bottom view of the subcase  80 .  FIG. 19C  is a left side view of the subcase  80 .  FIG. 19D  is a right side view of the subcase  80 . 
     As shown in  FIG. 4 , the case  60  accommodates the light emitter  10 , the first emitter lead  20 , the second emitter lead  22 , the light receiver  15 , the first receiver lead  24 , and the second receiver lead  26  of the sensor module  5 , and the subcase  80 . The case body  61  accommodates the circuit-encapsulating portion  90 . The emitter case section  62  accommodates the light emitter  10 , the first emitter lead  20 , and the second emitter lead  22 . The receiver case section  63  accommodates the light receiver  15 , the first receiver lead  24 , and the second receiver lead  26 . The circuit-encapsulating portion  90  is supported on the base plate  98 . The base plate  98  is engaged with a part of the case body  61  and is fixed. 
     The subcase  80  includes a first top plate  81 , a second top plate  83 , a first wall portion  82 , a second wall portion  84 , and a base plate portion  85 . The subcase  80  is formed from a material that allows light with a specific frequency (e.g., infrared light) emitted from the light emitting element  11  to pass through. The first wall portion  82  extends perpendicularly from one end of the base plate portion  85 . The second wall portion  84  extends perpendicularly from the other end of the base plate portion  85  and in the same direction as the direction in which the first wall portion  82  extends. In other words, the base plate portion  85  joins the first wall portion  82  and the second wall portion  84 . The direction in which the first wall portion  82  and the second wall portion  84  from the base plate portion  85  is referred to as a third direction. The first top plate  81  extends in a first outward direction from the top end of the first wall portion  82  in the third direction. The top end of the first wall portion  82  in the third direction is located opposite to the basal end of the first wall portion  82  in the third direction, which is in contact with the base plate portion  85 . The first outward direction refers to a direction from the basal end of the second wall portion  84  toward the basal end of the first wall portion  82  in the third direction. The second top plate  83  extends in a second outward direction from the top end of the second wall portion  84  opposite to the basal end of the second wall portion  84  in the third direction, which is in contact with the base plate portion  85 . The second outward direction refers to a direction from the basal end of the first wall portion  82  toward the basal end of the second wall portion  84 . The first top plate  81 , the second top plate  83 , and the base plate portion  85  are parallel to each other. The first wall portion  82  is parallel to the second wall portion  84 . 
     As shown in  FIGS. 4 and 5 , the first top plate  81  and the first wall portion  82  are placed into the emitter case section  62 . The second top plate  83  and the second wall portion  84  are placed into the receiver case section  63 . Referring to  FIG. 5 , the first wall portion  82  comes in contact with a first inner wall surface  64   a  of the emitter case section  62  facing the light emitter  10 . The second wall portion  84  comes in contact with a second inner wall surface  65   a  of the receiver case section  63  facing the light receiver  15 . Referring to  FIG. 4 , an end  81   a  of the first top plate  81  facing in the direction opposite to the direction in which light from the light emitter  10  travels (the negative direction of X axis) comes in contact with the third inner wall surface  64   b  of the emitter case section  62  facing the first inner wall surface  64   a . An end  83   a  of the second top plate  83  facing in the direction in which the light travels (the positive direction of X axis) comes in contact with the fourth inner wall surface  65   b  of the receiver case section  63  facing the second inner wall surface  65   a . The end  81   a  and the end  83   a  may not be flat, but may have protrusions or may be sharp. The third inner wall surface  64   b  extends from the inside of the emitter case section  62  to the basal end of the case body  61 . The fourth inner wall surface  65   b  extends from the inside of the receiver case section  63  to the basal end of the case body  61 . This structure allows the subcase  80  to be placed into the case  60  while allowing the subcase  80  to slide on the first inner wall surface  64   a , the second inner wall surface  65   a , the third inner wall surface  64   b , and the fourth inner wall surface  65   b  of the case  60 . This achieves smooth placement of the subcase  80  into the case  60 . This structure also prevents the first wall portion  82  and the second wall portion  84  from touching the inner wall surface of the case  60  and being deformed when the subcase  80  is placed into the case  60 . The subcase  80  and the case  60  with the structures described above allow the subcase  80  to be easily placed by using a machine. 
     As shown in  FIG. 4 , the first top plate  81  faces the fifth inner wall surface  64   c  of the emitter case section  62  facing the case body  61 . In other words, the first top plate  81  faces the case body  61 . Further, the second top plate  83  faces the sixth inner wall surface  65   c  of the receiver case section  63  facing the case body  61 . In other words, the second top plate  83  faces the case body  61 . When the subcase  80  is placed into the case  60  by using a machine, the machine may detect a pressure generated when the first top plate  81  comes in contact with the fifth inner wall surface  64   c  and the second top plate  83  comes in contact with the sixth inner wall surface  65   c . This allows the machine to detect that the subcase has been placed completely, and allows easier placement of the subcase by using a machine. 
     Referring to  FIG. 19B  and  FIG. 5 , the first wall portion  82  includes a first wall surface  82   a , a second wall surface  82   b , a first groove  82   c , and a first protrusion  82   d . The first wall surface  82   a  comes in contact with the first inner wall surface  64   a . The second wall surface  82   b  is opposite to the first wall surface  82   a . The first groove  82   c  is arranged on the second wall surface  82   b , and comes in contact with a part of the emitter lens  14 . The first protrusion  82   d  is arranged on the first wall surface  82   a , and protrudes in the direction toward the second wall portion  84 . The first protrusion  82   d  protrudes in conformance with the recess of the first groove  82   c.    
     Referring to  FIG. 19B  and  FIG. 5 , the second wall portion  84  includes a third wall surface  84   a , a fourth wall surface  84   b , a second groove  84   c , and a second protrusion  84   d . The third wall surface  84   a  comes in contact with the second inner wall surface  65   a . The fourth wall surface  84   b  is opposite to the third wall surface  84   a . The second groove  84   c  is arranged on the fourth wall surface  84   b , and comes in contact with a part of the emitter lens  14 . The second protrusion  84   d  is arranged on the third wall surface  84   a , and protrudes in the direction toward the first wall portion  82 . The second protrusion  84   d  protrudes in conformance with the recess of the second groove  84   c.    
     When the sensor module  5  is placed in the case  60  encasing the subcase  80 , the emitter lens  14  slides on the first groove  82   c , and the receiver lens  19  slides on the second groove  84   c . Mechanically placing the sensor module  5  can allow the optical axis of the light emitter  10  and the optical axis of the light receiver  15  to be aligned with each other. The positions of the light emitter  10  and the light receiver  15  are fixed on the first groove  82   c  and the second groove  84   c . This structure prevents large misalignment between the optical axes of the emitter lens  14  and the receiver lens  19  when, for example, the photosensor  1  receives vibrations. 
     As shown in  FIG. 5 , the first protrusion  82   d  is engaged with the emitter slit  66 , and the second protrusion  84   d  is engaged with the receiver slit  67 . The emitter slit  66  and the receiver slit  67  each function as a guide in placing the subcase  80  into the case  60 . This further facilitates the operation of placing the subcase  8  into the case  60 . 
     As shown in  FIGS. 4 and 5 , the subcase  80  includes the first top plate  81 , the second top plate  83 , the first wall portion  82 , and the second wall portion  84  covering the top of the light emitter  10  and the light receiver  15 , and covering the right side and the upper side of the emitter lens  14  of the light emitter  10  and the left side and the upper side of the receiver lens  19  of the light receiver  15  from which light is emitted and received. This structure reduces static electricity that can be generated around the emitter case section  62  and the receiver case section  63  affecting the light emitting element  11 , the receiver element  16 , the first emitter lead  20 , the second emitter lead  22 , the first receiver lead  24 , and the second receiver lead  26 . 
     The case for encasing an outer L-shaped type also uses the subcase  80 .  FIG. 20  is a front view of an outer L-shaped photosensor  2 .  FIG. 21  is a top view of the outer L-shaped photosensor  2 .  FIG. 22  is an exploded perspective view of the outer L-shaped photosensor  2 . In  FIGS. 20 to 22 , the components that are the same as the components shown in  FIGS. 1 to 3  are given the same reference numerals as those components and will not be described. 
     As shown in  FIGS. 20 to 22 , the photosensor  2  differs from the photosensor  1  in the shape of its case  60   a . The case  60   a  includes an emitter case section  62  and a receiver case section  63  that are the same as in the case  60 . The photosensor  2  thus has all the characteristics described above associated with the subcase  80 , the emitter case section  62 , and the receiver case section  63 . The characteristics of the case associated with the subcase  80 , the emitter case section  62 , and the receiver case section  63  will not be described. 
     The case  60   a  includes a case body  61   a  with a shape different from the case body  61 . As shown in  FIG. 21 , the case body  60   a  includes an indicator lamp window  68  as an opening in the front. The indicator lamp window  68  allows visual checking of an operation indicator  92 . The case body  60   a  has mounting holes  69   a  and  69   b  in the direction perpendicular to the direction in which the emitter and receiver slits face each other (Y-axis direction in  FIG. 21 ). The holes  69   a  and  69   b  are formed through the case  60 . The photosensor  2  includes connecting terminals  50 , which are a part of the sensor module  5 . The connecting terminals  50  protrude frontward from the case  60   a . As shown in  FIG. 22 , the subcase  80  and the sensor module  6  are placed into the case  60   a  in this order. A base plate  98   a  for supporting the circuit-encapsulating portion  90  is then attached to the bottom of the case  60   a.    
       FIG. 23  is a cross-sectional view of the photosensor  2  taken along line XXIII-XXIII of  FIG. 21 . With reference to  FIG. 23 , the characteristics of the inside of the case body  61   a  will be described. First, the third inner wall surface  64   b  extends from the inside of the emitter case section  62  to the basal end of the case body  61   a . The fourth inner wall surface  65   b  extends from the inside of the receiver case section  63  to the basal end of the case body  61   a . The circuit-encapsulating portion  90  is supported by the base plate  98   a . The circuit-encapsulating portion  90  comes in contact with the base plate portion  85  of the subcase  80  and supports the base plate portion  85 . 
     Although the embodiment of the present invention has been described, the invention should not be limited to the above embodiment. Various modifications are possible without departing from the scope and spirit of the invention. 
     The position of the light emitter  10  and the position of the light receiver  15  may be reversed. When the positions of the light emitter  10  and the light receiver  15  are reversed, the position of the first emitter lead  20  and the position of the first receiver lead  24  are reversed, and the position of the second emitter lead  22  and the position of the second receiver lead  26  are reversed in accordance with the positions of the light emitter  10  and the light receiver  15 . The position of the emitter case section  62  and the position of the receiver case section  63  are also reversed accordingly. 
     The emitter lens  14  and the receiver lens  19  may not be circular. For example, the emitter lens  14  and the receiver lens  19  may be oval. 
     The number of connecting terminals may not be four. The sensor modules  4 ,  5 , and  6  may include more than four or less than four connecting terminals. The sensor modules  4 ,  5 , and  6  may not include the operation indicator  92 . 
     INDUSTRIAL APPLICABILITY 
     The photosensor of the present invention includes a sensor module in which emitter and receiver leads protrude from a circuit-encapsulating portion in a direction intersecting with a direction in which external connecting terminals extend. 
     REFERENCE SIGNS LIST 
     
         
           1 ,  2  photosensor 
           10  light emitter 
           15  light receiver 
           90  circuit-encapsulating portion 
           50  connecting terminal 
           20  first emitter lead 
           22  second emitter lead 
           24  first receiver lead 
           26  second receiver lead 
         L 1  first bending line 
         L 2  second bending line 
           202  first emitter lead 
           204  second emitter lead 
           206  third emitter lead 
           208  fourth emitter lead 
         B 1  first bending portion 
         B 2  second bending portion 
           224  seventh emitter lead (inclined light emitting portion) 
           264  seventh receiver lead (inclined light receiving portion)