Patent Publication Number: US-10777695-B2

Title: Photoelectronic sensor and sensor system

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the priority benefit of Japan Application No. 2018-047350, filed on Mar. 14, 2018. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification. 
     BACKGROUND 
     Technical Field 
     The present disclosure relates to a photoelectronic sensor and a sensor system. 
     Related Art 
     Among photoelectronic sensors for detecting existence of an object or the like exists a retroreflective photoelectronic sensor that has a light projecting unit and a light receiving unit (hereinafter referred to as a “light projecting and receiving unit”) disposed alongside each other and projects light toward a reflective plate that is disposed facing the light projecting and receiving unit with a detection region sandwiched therebetween (e.g., see Patent Document 1, etc.). When the light from the light projecting unit is reflected to the light receiving unit by the reflective plate, the retroreflective photoelectronic sensor grasps a reduction in the amount of light received by the light receiving unit due to shielding of the light by a detected object, and performs detection of the existence of the detected object, and the like. 
     In such a retroreflective photoelectronic sensor, in the case where a surface of the detected object is specular, since mirror reflected light reflected by the specular surface may be received by the light receiving unit, there is a possibility that a malfunction (hereinafter referred to as a “specular malfunction”) that determines nonexistence of the detected object may occur, even though the detected object exists in the detection area. Therefore, the retroreflective photoelectronic sensor has a problem with stability of a detection operation led to by the specular malfunction. 
     Accordingly, as exemplified in  FIG. 6 , there has been proposed an approach of providing a light shielding plate S having a slit in front of a light receiving element  300 , using the fact that mirror reflected light  520  from a specular object W and reflected light  420  from a reflective plate  200  have different incident angles with respect to an optical axis of a light receiving lens  320 . The approach uses the fact that the reflected light  420  passes through the slit of the light shielding plate S and is incident on the light receiving element  300 , while the mirror reflected light  520  is shielded by the light shielding plate S. 
     PATENT DOCUMENT(S) 
     [Patent Document 1] Japanese Laid-open No. 2015-172564 
     However, as exemplified in  FIG. 7 , in the actual retroreflective photoelectronic sensor, light from a light projecting element  100  spreads conically to be projected. The conically spreading light includes, for example, projection light  500  from an area  100   a  on a side closer to the light receiving element  300  than an optical axis P of a light projecting lens  120  and projection light  600  from an area  100   b  on a side farther from the light receiving element  300  than the optical axis P, with respect to the specular object W. In the above method of shielding the mirror reflected light by the light shielding plate S, as illustrated in an enlarged view of the vicinity of the light receiving element  300  in the lower portion of  FIG. 7 , since the reflected light  420  from the reflective plate  200  and mirror reflected light  620  caused by the projection light  600  have no difference in incident angle with respect to an optical axis of the light receiving lens  320 , both the reflected light  420  and the mirror reflected light  620  may pass through the slit of the light shielding plate S, and it is difficult to shield the mirror reflected light  620  by the light shielding plate S. 
     The present disclosure provides a photoelectronic sensor and a sensor system capable of easily improving stability of the detection operation. 
     SUMMARY 
     A photoelectronic sensor according to an embodiment of the present disclosure includes: a light projecting unit, having a light projecting lens converging light and a light projecting element projecting light toward a reflective plate via the light projecting lens; and a light receiving unit disposed alongside the light projecting unit, having a light receiving lens concentrating reflected light from the reflective plate and a light receiving element receiving the reflected light via the light receiving lens, wherein the light projecting element has a light emitting area and a non-light emitting area, the light emitting area being located on a side closer to the light receiving element than an optical axis of the light projecting lens and emitting light and the non-light emitting area being located on a side farther from the light receiving element than the optical axis and not emitting light. 
     A sensor system according to an embodiment of the present disclosure includes the photoelectronic sensor, and a relay apparatus receiving control data for controlling the photoelectronic sensor from an external terminal apparatus connected via a network, wherein the photoelectronic sensor further has a communication interface capable of digitally communicating with the relay apparatus, and the light projecting element causes an area located on a side closer to the light receiving element than the optical axis of the light projecting lens to emit light and causes an area located on a side farther from the light receiving element than the optical axis to not emit light based on the control data received from the replay apparatus. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a principle diagram of a photoelectronic sensor according to a first embodiment. 
         FIG. 2A  is a plan view illustrating a configuration of a light projecting element according to the first embodiment.  FIG. 2B  is a side view illustrating a configuration of the light projecting element according to the first embodiment. 
         FIGS. 3A and 3B  are schematic diagrams illustrating light emitting patterns of the light projecting element according to the first embodiment, wherein  FIG. 3A  shows the case where a light emitting area and a non-light emitting area are formed, and  FIG. 3B  shows the case where only the light emitting area is formed. 
         FIG. 4  is a system diagram illustrating a system configuration of a sensor system according to a second embodiment. 
         FIGS. 5A and 5B  are schematic diagrams illustrating light emitting patterns of a light projecting element according to the second embodiment, wherein  FIG. 5A  shows the case where an area where light emitting elements are disposed is divided into two areas, and  FIG. 5B  shows the case where the area where the light emitting elements are disposed is divided into four areas. 
         FIG. 6  is a principle diagram of a conventional retroreflective photoelectronic sensor. 
         FIG. 7  is a principle diagram of occurrence of a specular malfunction of the conventional retroreflective photoelectronic sensor. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     A photoelectronic sensor according to an embodiment of the present disclosure includes: a light projecting unit, having a light projecting lens converging light and a light projecting element projecting light toward a reflective plate via the light projecting lens; and a light receiving unit disposed alongside the light projecting unit, having a light receiving lens concentrating reflected light from the reflective plate and a light receiving element receiving the reflected light via the light receiving lens, wherein the light projecting element has a light emitting area and a non-light emitting area, the light emitting area being located on a side closer to the light receiving element than an optical axis of the light projecting lens and emitting light and the non-light emitting area being located on a side farther from the light receiving element than the optical axis and not emitting light. 
     According to this embodiment, in the light projecting element of the photoelectronic sensor, by having the light emitting area and the non-light emitting area, while the light for object detection is projected, projection of light that could be a main cause of the mirror reflected light incident on the light receiving element can be suppressed. Therefore, a specular malfunction can be easily suppressed and stability of the detection operation can be easily improved. 
     In the above embodiment, the light emitting area may be divided into a plurality of partial areas that selectively emit light. 
     According to this embodiment, since the light projecting element can selectively emit light for each partial area, it is possible to realize differences in projected light spot diameter and amount of light by the same light projecting element module. 
     In the above embodiment, the light projecting element may have a plurality of LED elements that are disposed on a substrate. The LED elements disposed in the light emitting area may be electrically connected to electrodes of the substrate via wires, and the LED elements disposed in the non-light emitting area may not be electrically connected to the electrodes of the substrate. 
     According to this embodiment, it is possible to easily form the light emitting area and the non-light emitting area by connecting or not connecting to the wires. 
     A sensor system according to an embodiment of the present disclosure includes the photoelectronic sensor, and a relay apparatus receiving control data for controlling the photoelectronic sensor from an external terminal apparatus connected via a network, wherein the photoelectronic sensor further has a communication interface capable of digitally communicating with the relay apparatus, and the light projecting element causes an area located on a side closer to the light receiving element than the optical axis of the light projecting lens to emit light and causes an area located on a side farther from the light receiving element than the optical axis to not emit light based on the control data received from the replay apparatus. 
     According to this embodiment, in the sensor system using the photoelectronic sensor, by the control from the external terminal apparatus, it is possible to easily form the light emitting area and the non-light emitting area and improve stability of the detection operation. 
     According to the present disclosure, it is possible to provide the photoelectronic sensor and the sensor system capable of easily improving operation stability. 
     First Embodiment 
     An embodiment (hereinafter referred to as a “first embodiment”) of the present disclosure will be explained with reference to the accompanying drawings. In the drawings, those denoted by the same reference numeral have the same or similar configuration. 
     &lt;Basic Principle&gt; 
     A principle of a photoelectronic sensor according to the first embodiment will be explained using  FIG. 1 .  FIG. 1  schematically illustrates the principle of the photoelectronic sensor according to the present embodiment. For easy understanding of the explanation, projection light and reflected light are illustrated as representative light beams only. 
     A photoelectronic sensor  1  according to the present embodiment is a retroreflective photoelectronic sensor for detecting existence of an object, and the like. Inside the photoelectronic sensor  1 , a light projecting unit  14  and a light receiving unit  34  are disposed alongside each other. The photoelectronic sensor  1  projects light from the light projecting unit  14  toward a reflective plate  20  that is disposed facing the photoelectronic sensor  1  with a detection area sandwiched therebetween and receives reflected light from the reflective plate  20  by the light receiving unit  34 . Since a detected object passing through the detection area shields the projected light, the photoelectronic sensor  1  grasps a reduction in the amount of light received by the light receiving unit  34  and performs the detection. 
     The light projecting unit  14  includes a light projecting element  10  and a light projecting lens  12 . The light projecting element  10  is an element for projecting light toward the reflective plate  20  via the light projecting lens  12 . The light projecting element  10  may be, for example, an element such as a light emitting diode (LED), a laser diode (LD), or the like. By using an LED element as the light projecting element  10 , a later-described light emitting area can be accurately implemented. 
     In addition, the light projecting element  10  has a light emitting area  11   a  that is located on a side closer to a light receiving element  30  than an optical axis P of the light projecting lens  12 , the side being hereinafter simply referred to as the “side close to the light receiving element  30 ”, and that emits light, and a non-light emitting area  11   b  that is located on a side farther from the light receiving element  30  than the optical axis P, the side being hereinafter simply referred to as the “side far from the light receiving element  30 ”, and that does not emit light. The light projecting lens  12  is a lens for converging the light projected from the light projecting element  10 . 
     Herein, the “light emitting area” is an area in the light projecting element  10  that emits light, while the “non-light emitting area” is an area in the light projecting element  10  that does not emit light. For the light emitting area and the non-light emitting area, for example, the light emitting elements such as LED elements or the like may be disposed in both areas, or emission or non-emission of light may be selected by wire bonding to be described later. Accordingly, by wire bonding or the like, the light emitting area and the non-light emitting area can be easily formed. 
     The light receiving unit  34  includes the light receiving element  30  and a light receiving lens  32 . The light receiving element  30  is an element for receiving reflected light  42  from the reflective plate  20  via the light receiving lens  32 . The light receiving element  30  may be, for example, a photodiode, a position detecting element, or the like. The light receiving lens  32  is an optical adjustment means for forming the light incident from the detection area and the like into an image on the light receiving element  30 , and is, for example, a lens concentrating the reflected light  42  from the reflective plate  20 . 
     The photoelectronic sensor  1  projects projection light  40  from the light emitting area  11   a  of the light projecting element  10  toward the reflective plate  20 . In the photoelectronic sensor  1 , in the case where there is no specular object W serving as the detected object in the detection area, the projection light  40  is converged via the light projecting lens  12  to reach the reflective plate  20 . Thereafter, the projection light  40  is reflected by the reflective plate  20  and then becomes the reflected light (regressive light)  42 . The reflected light  42  is concentrated by the light receiving lens  32  and then is received by the light receiving element  30 . In the example of  FIG. 1 , although it is described that the reflected light  42  forms a predetermined angle relative to the projection light  40  so as to facilitate the explanation, actually, since the reflective plate  20  is disposed at an interval away from the light projecting and receiving unit compared to a baseline length (light emitting and receiving interval) L 1 , an optical path of the reflected light  42  is changed and the reflected light  42  is reflected by the reflective plate  20  so as to be opposed substantially parallel to the projection light  40 . By being reflected substantially parallel to the projection light  40  in this manner, the reflected light  42  is incident on the light receiving lens  32  substantially parallel to an optical axis of the light receiving lens  32 , and therefore can be concentrated by the light receiving lens  32  and received by the light receiving element  30 . 
     On the other hand, in the photoelectronic sensor  1 , in the case where the specular object W exists in the detection area, projection light  50  from the light emitting area  11   a  is projected on the specular object W via the light projecting lens  12  and is reflected by the specular object W to become mirror reflected light  52 . Unlike the above reflected light  42  that is substantially parallel incident, the mirror reflected light  52  is incident at a certain angle with respect to the optical axis of the light receiving lens  32 , and therefore is concentrated in a position away from the optical axis of the light receiving lens  32  and cannot be received by the light receiving element  30 . Accordingly, when the specular object W exists in the detection area, the photoelectronic sensor  1  can grasp a reduction in the amount of light received by the light receiving element  30  and can detect the existence of the specular object W. 
     According to the above configuration, in the retroreflective photoelectronic sensor, while the light for object detection is projected by the light emitting area, projection of light that could be a main cause of the mirror reflected light incident on the light receiving element can be suppressed by providing the non-light emitting area. Therefore, a specular malfunction can be easily suppressed and stability of the detection operation can be easily improved. 
     In the conventional retroreflective photoelectronic sensor illustrated in  FIG. 7 , although it is conceivable to increase the baseline length (light projecting and receiving interval) L 1  to thereby create a difference between incident angles of the reflected light  420  and the mirror reflected light  620  with respect to the optical axis of the light receiving lens  320  and make it easier for the light shielding plate S to shield light, as the baseline length is increased, the photoelectronic sensor  1  may be accordingly increased in size. Therefore, it may become difficult to dispose the photoelectronic sensor  1  in various detection environments or arrangement places. Further, although a method of shielding the projection light being a main cause of the mirror reflected light by the light shielding plate may also be considered, there is an aspect that a position of the light shielding plate is required to be controlled with high precision, and the assembly is troublesome. 
     &lt;Configuration Example of Light Projecting Element&gt; 
     An example of a configuration of the light projecting element  10  (LED chip) according to the present embodiment will be described using  FIGS. 2A and 2B .  FIG. 2A  is a plan view showing an example of the configuration of the light projecting element  10 .  FIG. 2B  is a side view showing an example of the configuration of the light projecting element  10 . Although in the example of  FIGS. 2A and 2B , only the light projecting element  10  is shown, when the light projecting element  10  is viewed in a plan view, the light receiving element  30  may be arranged alongside in a longitudinal direction of the light projecting element  10  and disposed on a side of a bonding pad  19 . 
     In the example of  FIGS. 2A and 2B , the light projecting element  10  is formed of the light emitting area  11   a , a light emitting area  11   b , and a light emitting area  11   c  (hereinafter collectively referred to as a “light emitting area  11 ”), a p electrode  15   a , a p-type cladding layer  15   b , an active layer  15   c , an n-type cladding layer  15   d , an n-type substrate  15   e , an n electrode  15   f , and the bonding pad  19 . 
     The light projecting element  10  may have the active layer  15   c  that is located between the p-type cladding layer  15   b  and the n-type cladding layer  15   d  and may further have the n-type substrate  15   e  as a single crystal substrate. An LED element included in the light projecting element  10  is capable of efficiently generating light from the active layer  15   c  by flowing an electric current between the p electrode  15   a  and the n electrode  15   f . Further, the light projecting element  10  is configured so that, when viewed in a plan view, the p electrode  15   a  is disposed to cover the p-type cladding layer  15   b  except the light emitting area  11 , and the light generated by the active layer  15   c  is emitted from the light emitting area  11  to the outside. The p electrode  15   a  may have a thickness enough to shield the light generated by the active layer  15   c . According to such a configuration, the light from the active layer  15   c  can be emitted only in the light emitting area  11 . Alternatively, in a plan view of the light projecting element  10 , the active layer  15   c  may have a structure so as to emit light according to a light emitting pattern of the light emitting area  11 . The light emitting area  11  may only be an area of a semicircular portion located closer to the light receiving element  30  than an optical axis of a light projecting lens (not shown) in a substantially circular area centered on the optical axis of the light projecting lens (not shown). According to such a configuration, light emission can only be performed by the area located on a side closer to the light receiving element  30  than the optical axis of the light projecting lens (not shown). 
     The p electrode  15   a  and the n electrode  15   f  are made of a gold alloy. 
     Each layer of a p-type semiconductor and an n-type semiconductor may be, for example, formed by a double hetero-structure made of a compound semiconductor such as GaAs, GaP, AlGaInP, InGaN, etc. which is stacked by epitaxial growth; specifically, the p-type cladding layer  15   b  and the n-type cladding layer  15   d  may be formed of a compound semiconductor of a GaAs-based ternary system or a Si-based semiconductor, the active layer  15   c  may be formed of a quaternary system compound semiconductor such as AlGaInP, etc., and the n-type substrate  15   e  may be formed of GaAs. 
     The bonding pad  19  is an electrode for electrically connecting the LED element to external wiring. The bonding pad  19  may be provided on the p electrode  15   a  and may be electrically connected to the external wiring via a wire (not shown). 
     &lt;Example of Light Emitting Pattern&gt; 
     Examples of the light emitting pattern of the light projecting element  10  according to the present embodiment will be explained using  FIGS. 3A and 3B . The examples of  FIGS. 3A and 3B  are explained as the light receiving element  30  shown in  FIG. 1  is located at the bottom of the drawings, the side close to the light receiving element  30  is defined as a lower side of the drawings, and the side far from the light receiving element  30  is defined as an upper side of the drawings. 
       FIG. 3A  is a diagram schematically illustrating an example of the light emitting pattern of the light projecting element  10 .  FIG. 3B  is a diagram schematically illustrating another example of the light emitting pattern of the light projecting element  10 . 
     In the example of  FIG. 3A , the light projecting element  10  has the light emitting area  11   a  on the side close to the light receiving element  30  and the non-light emitting area  11   b  on the side far from the light receiving element  30 . The light emitting area  11   a  and the non-light emitting area  11   b  may be respectively formed by dividing an area where the light emitting elements are disposed into two areas, i.e., the area on the side close to the light receiving element  30  and the area on the side far from the light receiving element  30 . 
     The light emitting area  11   a  is, for example, electrically connected to a bonding pad  19   a  that is disposed in the light projecting element  10  via a wire  18   a . The non-light emitting area  11   b  is, for example, not electrically connected to a bonding pad  19   b  that is disposed in the light projecting element  10 . According to such a configuration, in the light projecting element  10 , since the light emitting area  11   a  and the non-light emitting area  11   b  can be easily formed by connecting or not connecting to the wire, specular malfunction can be suppressed and stability of the detection operation can be improved. 
     In the example of  FIG. 3B , in the light projecting element  10 , the light emitting area  11   a  is formed on the side close to the light receiving element  30  and the light emitting area  11   b  is also formed on the side far from the light receiving element  30 . The light emitting area  11   a  may be connected to the bonding pad  19   a  via the wire  18   a , and the light emitting area  11   b  may be electrically connected to the bonding pad  19   b  via a wire  18   b.    
     According to the above configuration, the light projecting element  10  can change its light emitting pattern by electrically connecting or not electrically connecting the area  11   b  to the bonding pad  19   b  by the wire  18   b . Accordingly, in the light projecting element  10 , for example, by using the same light projecting element module and only changing the connection of the wire, the light emitting pattern of  FIG. 3A  can be used in the case where it is desired to secure operation stability even at the expense of detection distance, and the light emitting pattern of  FIG. 3B  can be used in the case where it is desired to increase the detection distance even at the expense of operation stability. That is, it is possible to provide a highly versatile photoelectronic sensor capable of easily realizing a change in the light emitting pattern using the same sensor module. 
     In the light projecting element  10 , for example, the light emitting area  11   a  may further be divided into a plurality of partial areas. In addition, a plurality of bonding pads may be disposed corresponding to the partial areas and may be connected to the partial areas via wires respectively. According to such a configuration, by using the same light projecting element module and only changing the connection of the wire, a projected light spot diameter and the amount of light can be easily changed. Accordingly, it is possible to provide a highly versatile photoelectronic sensor that realizes differences in the projected light spot diameter and the amount of light by the same light projecting element module. 
     Second Embodiment 
     Next, a second embodiment of the present disclosure will be described. In the drawings, those denoted by the same reference numerals have the same or similar configuration. The second embodiment is an embodiment of a sensor system using the photoelectronic sensor according to the first embodiment. Only the differences from the first embodiment will be described below. 
     &lt;System Configuration Example&gt; 
     An example of the system configuration of a sensor system  1000  according to the present embodiment will be described using  FIG. 4 . 
     The sensor system  1000  is, for example, a system using a communication protocol such as an IO-Link (registered trademark) protocol, etc. The sensor system  1000  is a system that digitizes a sensor including the photoelectronic sensor according to the first embodiment, an actuator, etc. and capable of communicating with an external terminal apparatus connected via a network. The system using the IO-Link is, for example, a system including a master apparatus (control apparatus), a slave apparatus (relay apparatus) and a device such as a sensor, etc., wherein the master apparatus performs operation control of the device and receives output data of the device via the slave apparatus. This content has been explained in detail in the past patent documents (e.g., Japanese Laid-open No. 2017-167593), etc. of the applicant, and therefore the explanation will be omitted herein. 
     In photoelectronic sensors  70   a ,  70   b  and  70   c  (hereinafter collectively referred to as a “photoelectronic sensor  70 ”) of the sensor system  1000 , all areas with light emitting elements disposed therein are electrically connected to external wiring. Formation of a light emitting area and a non-light emitting area in the photoelectronic sensor  70  is controlled by control data transmitted from a terminal apparatus  80  equivalent to the above master apparatus to the photoelectronic sensor  70  equivalent to the above device and designating the light emitting element through which an electric current flows. 
     Herein, the “control data” is data for controlling a light emitting operation of the photoelectronic sensor  70 , and is data for, for example, designating which light emitting element of the photoelectronic sensor  70  the electric current flows through (which light emitting element is to be lit up) or for adjusting a voltage applied to the light emitting element (the amount of light of the light emitting element). In addition, the control data may include data (e.g., Light-On/Dark-On settings that define whether to output an ON signal upon detection of light or to output the ON signal when no light is detected) for controlling the detection operation of the photoelectronic sensor  70 . 
     The photoelectronic sensor  70  has the same configuration and function as the photoelectronic sensor  1  according to the first embodiment. A difference from the first embodiment is that in the photoelectronic sensor  70 , all the light emitting elements are electrically connected to the external wiring via the wires. In the photoelectronic sensor  70 , at least some of the light emitting elements are lit up and to form the light emitting area and the non-light emitting area based on the control data transmitted from the external terminal apparatus  80  and received via a relay apparatus  75 . According to such a configuration, in the photoelectronic sensor  70 , without changing physical connection by wire bonding, by the control data from the terminal apparatus  80 , the light emitting area and the non-light emitting area can be formed, and the light emitting pattern can be changed. Further, the photoelectronic sensor  70  may, for example, further have a communication interface capable of digitally communicating with the relay apparatus  75 . 
     The relay apparatus  75  is an apparatus for relaying various data between the external terminal apparatus  80  connected via a network and the photoelectronic sensor  70 , such as receiving the control data from the external terminal apparatus  80 , transmitting the control data to the photoelectronic sensor  70 , and so on. 
     The terminal apparatus  80  is a terminal for operating a device such as a sensor, an actuator, etc. and is, for example, a programmable logic controller (PLC), a human machine interface (HMI), etc. For example, the terminal apparatus  80  accepts operation input of a light emitting operation in the photoelectronic sensor  70  from a user and generates the control data indicating a light emitting operation such as through which light emitting element an electric current flows and, which level of voltage is to be applied and so on based on the accepted input content. The terminal apparatus  80  transmits the generated control data to the photoelectronic sensor  70  via the relay apparatus  75  and the network. 
     The sensor system  1000  is a system including the relay apparatus  75  and the photoelectronic sensor  70 . In the sensor system  1000 , the external terminal apparatus  80  is equivalent to the master apparatus in the above system using the IO-Link, and the relay apparatus  75  is equivalent to the slave apparatus in the above system using the IO-Link. In  FIG. 4 , although one relay apparatus  75  and three photoelectronic sensors  70  are shown, the number of each of the relay apparatus  75  and the photoelectronic sensor  70  may be one or more. 
     In the sensor system  1000 , based on the control data for controlling the photoelectronic sensor  70  that is received from the relay apparatus  75 , an area in the photoelectronic sensor  70  located on the side close to the light receiving element  30  (not shown) is caused to emit light and an area located on the side far from the light receiving element  30  (not shown) is caused to emit light. 
     According to the above configuration, by operation from the external terminal apparatus  80 , the light emitting pattern of the photoelectronic sensor  70  can be changed. Therefore, it is possible to provide a sensor system that achieves both stability of the detection operation and an increase in versatility. 
     &lt;Configuration Example of Light Projecting Element&gt; 
     A configuration of the light projecting element of the photoelectronic sensor  70  according to the present embodiment is the same as the first embodiment. A difference from the first embodiment is that in the light projecting element according to the present embodiment, for example, all the areas where light emitting elements are disposed, including the light emitting area and the non-light emitting area, are electrically connected to the external wiring via the wires. 
     &lt;Example of Light Emitting Pattern&gt; 
     Examples of the light emitting pattern of the light projecting element  10  of the photoelectronic sensor  70  according to the present embodiment will be described using  FIGS. 5A  and B. The examples of  FIGS. 5A  and B are explained as the light receiving element  30  shown in  FIG. 1  is located at the bottom of the drawings, the side close to the light receiving element  30  is defined as a lower side of the drawings, and the side far from the light receiving element  30  is defined as an upper side of the drawings. 
       FIG. 5A  is a diagram schematically illustrating an example of the light emitting pattern of the light projecting element  10 .  FIG. 5B  is a diagram schematically illustrating another example of the light emitting pattern of the light projecting element  10 . 
     In the example of  FIG. 5A , an area of the light projecting element  10  is divided into two areas, i.e., an area  11   a  located on the side close to the light receiving element  30  and an area  11   b  located on the side far from the light receiving element  30 . The areas  11   a  and  11   b  are electrically connected to the bonding pads  19   a  and  19   b  via bonding wires (not shown) respectively. In the sensor system  1000 , for example, in the case where the photoelectronic sensor  70  is used as a retroreflective photoelectronic sensor, control may be performed from the terminal apparatus  80  to only light up the light emitting elements disposed in the area  11   a  so as to set the area  11   a  as a light emitting area and the area  11   b  as a non-light emitting area. On the other hand, in the sensor system  1000 , in the case where the photoelectronic sensor  70  is used as a transmissive photoelectronic sensor, control may be performed from the terminal apparatus  80  to light up the light emitting elements disposed in the respective areas to set both the areas  11   a  and  11   b  as light emitting areas. According to such a configuration, by using the same sensor module without physically changing the connection to the bonding wires, only by operation from the terminal apparatus  80 , the light emitting pattern can be changed and various uses are possible. That is, it is possible to realize a highly versatile sensor system while ensuring stability of the detection operation. 
     Herein, the “transmissive photoelectronic sensor” is a photoelectronic sensor in which a light projecting unit that projects light and a light receiving unit that receives projection light of the light projecting unit are disposed facing each other, and the projection light from the light projecting unit projected on the light receiving unit in a substantially straight line manner. In the transmissive photoelectronic sensor, a detection area is provided between the light projecting unit and the light receiving unit that are disposed facing each other, an detected object passing through the detection area shields the projection light, and the amount of light received by the light receiving unit decreases, thereby detecting the detected object. 
     In the example of  FIG. 5B , the light projecting element  10  is further divided from that in the example of  FIG. 5A  into a plurality of partial areas, such that the area  11   a  is divided into partial areas  11   a   1  and  11   a   2  and the area  11   b  is divided into partial areas  11   b   1  and  11   b   2  and the partial areas selectively emit light. The areas  11   a   1 ,  11   a   2 ,  11   b   1  and  11   b   2  are electrically connected to bonding pads  19   a   1 ,  19   a   2 ,  19   b   1  and  19   b   2  via bonding wires (not shown) respectively. According to such a configuration, since the projected light spot diameter and the amount of light can be easily changed using the same sensor module, it is possible to provide a highly versatile sensor system that realizes differences in the projected light spot diameter and the amount of light by the same light projecting element module. 
     [Others] 
     The photoelectronic sensor according to the present disclosure can also be used for a distance setting type of a diffuse-reflection-type photoelectronic sensor. By changing the light emitting pattern of the light projecting element, it is possible to easily adjust a set distance without adjusting a position of a lens. In the case of such use, the light receiving element uses a two-division photodiode in which a distance from a sensor body and the detected object is divided into two areas, i.e., the near side and the far side. 
     Herein, the “diffuse-reflection-type photoelectronic sensor” is a photoelectronic sensor in which the light projecting unit projecting light and the light receiving unit receiving the projection light of the light projecting unit are disposed alongside each other, the projection light from the light projecting unit irradiates the detected object and diffuse-reflection light is received from the detected object. The diffuse-reflection-type photoelectronic sensor detects the existence of the detected object and the like by an increase in the amount of the diffuse-reflection light received from the detected object. 
     The embodiments described above are intended to facilitate understanding of the present disclosure, but not to limit the present disclosure. Each element included in the embodiments and the arrangement, material, condition, shape and size thereof, etc. are not limited to what has been illustrated and instead can be appropriately changed. In addition, it is possible to partially replace or combine the components shown in different embodiments.