Patent Publication Number: US-2006001655-A1

Title: Light-transmitting touch panel and detection device

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to light-transmitting touch panels used for operating electronic apparatuses, and to detection devices for detecting the proximity and touch of an operator&#39;s finger on light-transmitting touch panels.  
      2. Background Art  
      Increasing numbers of electronic apparatuses such as car navigation systems have a light-transmitting touch panel attached to the front face of a display device such as an LCD. In these apparatuses, the user can see characters, symbols and pictures displayed on the display device through the light-transmitting touch panel which is the operating face. At the same time, the user can select and activate characters, etc., by touching the operating face.  
      In the operation of car navigation systems, in particular, high accuracy is needed for detection of both proximity of the operator&#39;s finger to an operating face of the light-transmitting touch panel to a predetermined distance, and the position touched by the finger on the panel face.  
      A general light-transmitting touch panel of this type is described next with reference to  FIGS. 8 and 9 . As shown in  FIG. 8 , a conventional light-transmitting touch panel has light-transmitting substrate  1 , made typically of glass. Upper pattern  2 , consisting of multiple lines, is made of a conductive material and formed on the front face of substrate  1  parallel to the vertical direction in  FIG. 8 . The front face of substrate  1  is, for example, the operating face.  
      Lower pattern  3 , consisting of multiple lines, is made of a conductive material and formed on the back face of substrate  1  in a direction perpendicular to upper pattern  2 , i.e., parallel to the horizontal direction. This configures the light-transmitting touch panel.  
      Light-transmitting touch panel  100  as configured above is disposed on the front face of the display device, and attached to an electronic apparatus (not illustrated). In addition, each line of upper pattern  2  and lower pattern  3  is coupled to a sensing circuit (not illustrated) of the electronic apparatus.  
      When the finger comes close to the operating face of light-transmitting touch panel  100 , or the finger touches the operating face, the sensing circuit detects proximity or touched position of the finger by measuring the electrostatic capacity formed between the finger and the opposing pattern.  
      Next, an example of detecting a position when the finger comes close to around area P 1  in  FIG. 9  is described. When the finger comes closest to the n-th line in upper pattern  2 , the sensing circuit measures the electrostatic capacity between two adjacent lines in a sequence starting from the end of upper pattern  2 . Based on measurements of capacity between the (n−1)th and n-th lines, and between the n-th and (n+1)th lines in upper pattern  2  facing the finger, the sensing circuit detects that the finger is closest to the n-th line.  
      On the other hand, the finger is closest to the m-th line in lower pattern  3 . The sensing circuit detects that the finger is closest to the m-th line based on measurements of capacity between the (m−1)th and m-th lines, and between the m-th and (m+1)th lines in lower pattern  3  facing the finger.  
      As a result, the sensing circuit determines that the proximity position of the finger is an area where the n-th line and the m-th line cross.  
      In the same way, when the finger touches area P 1  on the panel, electrostatic capacity between adjacent lines is measured sequentially, and the area where the n-th line in upper pattern  2  and the m-th line in lower pattern  3  cross is detected as the position touched by the finger.  
      As described above, the general light-transmitting touch panel is configured to switch diverse functions of electronic apparatus by proximity position and touching position of the finger.  
      The electrostatic capacity increases in proportion to the size of the area where the finger and pattern oppose, and decreases in inverse proportion to the distance between the finger and pattern where they oppose. In other words, the electrostatic capacity increases as the pattern line width becomes wider and the finger comes closer to the pattern.  
      The general light-transmitting touch panel as described above is typically disclosed in International Publication number WO 01/027868 A1.  
      In the above general light-transmitting touch panel, the number of lines in upper pattern  2  and lower pattern  3  need to be increased to improve the detection accuracy of the touched position. However, the pattern line width becomes narrower with increasing number of lines in the pattern, and consequently the capacity to be measured becomes smaller. A smaller capacity makes it difficult to detect the proximity of the finger if the finger is further away from the pattern.  
      On the other hand, if the pattern line width is widened to detect proximity of the finger at a greater distance, the number of lines in the pattern is reduced, degrading the detection accuracy of the touched position.  
      Accordingly, in a conventional light-transmitting touch panel, there is a tradeoff between achieving detection of the proximity of a finger at a greater distance and improved detection accuracy of the touched position.  
     SUMMARY OF THE INVENTION  
      The present invention solves the disadvantage of the prior art as described above, and aims to offer a light-transmitting touch panel that shows improved detection capability with respect to both finger proximity distance and touched position, and that can also clearly distinguish between proximity and actual touching.  
      The light-transmitting touch panel of the present invention includes a transparent and flexible first substrate, a first transparent electrode which is patterned on the first face of the first substrate, a second transparent electrode formed on the second face of the first substrate, a transparent second substrate which faces the first substrate with a predetermined space in between, and a third transparent electrode formed on the second substrate and facing the second transparent electrode. Since the area of the first transparent electrode facing the finger is enlarged, the value of the capacitance of a capacitor formed between the finger and an opposing surface-conductive layer can be increased. The proximity can thus be detected from a greater distance. Presence of touch and the touched position are detected by measuring the voltage ratio while the second transparent electrode and opposing third transparent electrode are in contact. The above configuration offers a light-transmitting touch panel that can detect the proximity of a conductive object such as a finger from a certain distance, that can also detect the touched position with high accuracy, and that can clearly distinguish between detection of proximity and touching.  
      A detection device of the present invention includes the light-transmitting touch panel and a detector. The light-transmitting touch panel includes a transparent and flexible first substrate with a transparent electrode on both faces, and a second substrate facing the first substrate with a predetermined space in between. This second substrate has a transparent electrode facing the transparent electrodes on the back face of the first substrate. The detector is coupled to at least the transparent electrode on the front face, and includes a sensing circuit for detecting the proximity of a conductive object to the first substrate and a sensing circuit for detecting a contact of the first substrate and second substrate. This offers a detection device that can detect the proximity of a conductive object such as a finger and that can also detect the presence and position of a touch with a high degree of accuracy.  
      Still more, the detection device of the present invention includes the light-transmitting touch panel and detector. The light-transmitting touch panel has a transparent and flexible first substrate, the first transparent electrode patterned on the first face of the first substrate, the second transparent electrode formed on the second face of the first substrate, the transparent second substrate facing the first substrate with a predetermined space in between, and the third transparent electrode formed on the second substrate and facing the second transparent electrode. The detector has a capacitance-sensing circuit coupled to at least the first transparent electrode, and a voltage ratio-sensing circuit for detecting a contact of the second transparent electrode and third transparent electrode. This offers a detection device that can detect the proximity of a conductive object such as a finger and that can also detect the presence and position of a touch with a high degree of accuracy.  
      The detection device of the present invention is further provided with an alarm that generates sound, light, vibration, etc., in response to proximity or touch of a conductive object. For example, when the operator moves the finger close to an intended display on a display device, the detector detects the proximity of this finger and outputs a detection signal to the alarm. The alarm, on receiving this signal, generates sound, light, vibration, etc., such that the operator does not have to visually check the display every time. The operator can simply move the finger close to the intended display for confirming the display.  
      Accordingly, the present invention offers a light-transmitting touch panel that can detect the proximity of a conductive object such as a finger from a certain distance, that can also detect the touched position with high accuracy, and that can clearly distinguish between detection of proximity and touch. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a sectional view of a light-transmitting touch panel in accordance with a first exemplary embodiment of the present invention.  
       FIG. 2  is a plan view of the light-transmitting touch panel in accordance with the first exemplary embodiment of the present invention.  
       FIG. 3  is a schematic diagram illustrating touching of the light-transmitting touch panel in accordance with the first exemplary embodiment of the present invention.  
       FIGS. 4A and 4B  are schematic diagrams of a capacitance-sensing method in the light-transmitting touch panel in accordance with the first exemplary embodiment of the present invention.  
       FIGS. 5A and 5B  are schematic diagrams of the capacitance-sensing method in a light-transmitting touch panel in accordance with a second exemplary embodiment of the present invention.  
       FIG. 6  is a sectional view of a light-transmitting touch panel in accordance with a third exemplary embodiment of the present invention.  
       FIG. 7  is a plan view of the light-transmitting touch panel in accordance with the third exemplary embodiment of the present invention.  
       FIG. 8  is a sectional view of a general light-transmitting touch panel.  
       FIG. 9  illustrates a configuration of upper and lower patterns of the light-transmitting touch panel. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
       FIG. 1  is a sectional view of light-transmitting touch panel  101  in the first exemplary embodiment of the present invention. Light-transmitting touch panel  101  includes light-transmitting top substrate  11  (equivalent to the first substrate) and light-transmitting upper conductive layer  12  (equivalent to the second transparent electrode) formed on its back face. Top substrate (first substrate)  11  is typically made of a transparent resin film such as polyethylene terephthalate and polycarbonate. Upper conductive layer  12  is a light-transmitting conductive film typically made of indium tin oxide, using vacuum deposition or sputtering.  
      A pair of upper electrodes (not illustrated) is formed by printing paste, typically containing silver or carbon, on both ends of this upper conductive layer  12 .  
      On the surface of light-transmitting bottom substrate  13  (equivalent to the second substrate) made such as of glass, acryl1ic resin or polycarbonate resin, light-transmitting lower conductive layer  14  (equivalent to the third transparent electrode), typically made of indium tin oxide, is formed using the same method as that for upper conductive layer  12 .  
      On the surface of this lower conductive layer  14 , a pair of lower electrodes (not illustrated), the same as the upper electrodes, is disposed on both ends in a direction perpendicular to the upper electrodes. In addition, dot spacers (not illustrated) are formed at predetermined intervals so as to secure a predetermined space between lower conductive layer  14  and upper conductive layer  12 .  
      An adhesive layer (not illustrated) made of thermoplastic resin is applied on the front face and back face of frame spacer  16 , typically made of nonwoven fabric or polyester film.  
      Top substrate  11  and bottom substrate  13  are then attached at their peripheries via spacer  16  in such a way that upper conductive layer  12  and lower conductive layer  14  face each other with a predetermined space in between.  
      Light-transmitting surface-conductive layers  17 A to  17 D (equivalent to the first transparent electrode), typically made of indium tin oxide, are formed in predetermined areas on the front face of top substrate  11 , typically by vacuum sputtering.  
       FIG. 2  is a plan view of light-transmitting touch panel  101  seen from the operating side. As shown in  FIG. 2 , surface-conductive layers  17 A to  17 D are formed in planar fashion in predetermined areas at the upper left, upper right, lower left and lower right on the front face of top substrate  11 . Upper left electrode  18 A, upper right electrode  18 B, lower left electrode  18 C and lower right electrode  18 D are disposed on the ends of predetermined areas of each of surface-conductive layer by printing paste made such as of silver and carbon. Light-transmitting touch panel  101  is thus structured.  
      A detection device in the first exemplary embodiment includes aforementioned light-transmitting touch panel  101 ; and a detector (not illustrated) coupled to each electrode of surface-conductive layers  17 A to  17 D, upper conductive layer  12  and lower conductive layer  14  of light-transmitting touch panel  101 . A capacitance-sensing circuit is coupled between surface-conductive layers  17 A to  17 D and upper conductive layer  12 . A voltage ratio-sensing circuit is coupled to upper conductive layer  12  and lower conductive layer  14 . In addition, an alarm (not illustrated) can be coupled to the detector. The detector can be configured with semiconductor devices such as microcomputers, electrical circuits, and so on. The alarm can be configured to include audio equipment such as a buzzer or a speaker; lighting equipment such as a light-emitting diode and a lamp; or a vibrator such as motor or piezoelectric buzzer.  
      The light-transmitting touch panel as configured above is disposed on the surface of a display device of, for example, a car navigation apparatus. The detector and alarm are built into the car navigation apparatus, and the detector is coupled to a control circuit (not illustrated) of the car navigation apparatus.  
      The operation of the detection device employing light-transmitting touch panel  101  of the present invention is described next, taking an example of employing the detection device of the exemplary embodiment and a display unit in a car navigation apparatus.  
      In the detection device, the capacitance-sensing circuit repetitively detects a capacitance between surface-conductive layers  17 A,  17 B,  17 C and  17 D, and upper conductive layer  12  respectively and in turn.  
      When finger  10  is not in proximity, as shown schematically in  FIG. 4A , capacitance C 0  is detected between surface-conductive layers  17 B or  17 D and upper conductive layer  12 .  
      Next,  FIG. 3  shows the state where the operator sees a display on the display device disposed on the back face of light-transmitting touch panel  101  and moves a finger over light-transmitting touch panel  101  close to area a 3  (the border between surface-conductive layers  17 B and  17 D as shown in  FIG. 2 ).  
      In this state, a capacitor with capacitance C 1  is formed between finger  10  and a portion of surface-conductive layer  17 B facing finger  10 , and thus a capacitor with capacitance C 2  is created between upper conductive layer  12  and finger  10 . This capacitor, which is newly created when finger  10  comes in proximity to panel  101 , increases the capacitance detected between surface-conductive layer  17 B and upper conductive layer  12 .  
      The capacitance-sensing circuit detects the proximity of finger  10  to surface-conductive layer  17 B by detecting the difference in the measured capacitance. “Proximity” in the description refers to a distance of within 15 mm from the finger to the top substrate. In addition, a weak touch by a conductive object, such as a finger, which does not dent the top substrate, is also included in “proximity.” On the contrary, “touch” is a state in which the conductive object bents the top substrate so that upper conductive layer  12  comes in contact with lower conductive layer  14 .  
      As shown in  FIG. 2 , surface-conductive layer  17 B is formed not linearly but in a plane, and thus a capacitor is formed between the area of the finger and a portion of surface-conductive layer  17 B facing the finger which has the size equivalent to the area of the finger. Accordingly, the capacitance to be added can be made greater.  
      The sensing circuit detecting the proximity of the finger transmits a detection signal to the alarm. The alarm, on receiving this detection signal, generates a “bleep, bleep!” sound, and light or vibration, etc., simultaneously with the sound. This notifies the driver of the proximity of the finger to surface-conductive layer  17 B in area a 3 .  
      When the operator, such as the driver or a passenger, moves finger  10  close to areas a 1 , a 2  or a 4 , the capacitance-sensing circuit detects an increase in capacitance in the same way. More specifically, the capacitance-sensing circuit detects the proximity of a finger to a border area of surface-conductive layer  17 A,  17 B,  17 C or  17 D, and the detection signal corresponding to the respective border area is transmitted to the alarm.  
      The alarm, on receiving the detection signal corresponding to each of these areas, can separately notify the operator to which of surface-conductive layers  17 A,  17 C and  17 D the finger is in proximity. For example, when finger  10  is close to surface-conductive layer  17 A, the alarm makes a “bleep!” sound. When finger  10  is close to surface-conductive layer  17 C, the alarm makes three consecutive sounds, such as “bleep, bleep, bleep!” In the same way, when finger  10  is close to surface-conductive layer  17 D, the alarm makes four consecutive sounds of “bleep, bleep, bleep, bleep!” Moreover, instead of or in addition to these sounds, lighting, vibration, and so on can be generated.  
      In other words, the operator does not need to visually check the display every time, since the capacitance-sensing circuit detects the rough proximity position and the alarm generates sound, light, vibration, and so on corresponding to the proximity position when the operator moves a finger close to the surface of the display on the display device. The operator can therefore confirm the intended display just by moving the finger close to its surface.  
      Then, when the operator touches any portion of surface-conductive layer  17 B with a finger, top substrate  11  dents, and the portion of upper conductive layer  12  corresponding to the touched position contacts lower conductive layer  14 . A voltage ratio-sensing circuit can thus detect when the panel is being touched. In other words, the detector clearly distinguishes between detection of touch and proximity. The voltage ratio-sensing circuit further applies a voltage between upper conductive layer  12  and lower conductive layer  14 , and detects the exact position touched on first conductive layer  17 B by detecting the voltage ratio in upper conductive layer  12  and in lower conductive layer  14 .  
      Accordingly, if, for example, a display on the display device of the car navigation apparatus opposing the surface-conductive layer  17 B is a switch for “traffic information,” the driver can confirm that his/her finger is pointing at “traffic information” just by confirming the sound such as “bleep, bleep!” made when moving the finger close to the surface.  
      After the driver confirms that his/her finger is in proximity to “traffic information,” the driver can move the finger closer in the same direction and touch surface-conductive layer  17 B. The sensing circuit then detects which portion of this surface-conductive layer  17 B is being touched, and transmits a signal to the control circuit of the car navigation apparatus. Consequently, for example, the control circuit outputs “traffic information” in the form of sound through a speaker so that the driver and passengers can listen to “traffic information.” 
      In the above description, surface-conductive layers  17 A to  17 D are formed in predetermined areas on top substrate  11 . Alternatively, the present invention is also achievable by forming a surface-conductive layer over the entire front face of top substrate  11 .  
       FIGS. 5A and 5B  show the second exemplary embodiment of the present invention. The second exemplary embodiment also employs light-transmitting touch panel  101  in the first exemplary embodiment.  
      A detection device in the second exemplary embodiment is configured including aforementioned light-transmitting touch panel  101 ; and a detector (not illustrated) configured including a microcomputer and coupled to each electrode of surface conductive layers  17 A to  17 D, upper conductive layer  12  and lower conductive layer  14  of this light-transmitting touch panel  101 . The capacitance-sensing circuit is coupled to surface conductive layers  17 A to  17 D, and the voltage ratio-sensing circuit is coupled to upper conductive layer  12  and lower conductive layer  14 . In addition, an alarm (not illustrated) can be coupled to the detector.  
      The light-transmitting touch panel as configured above is disposed on the surface of a display device of, for example, a car navigation apparatus. The detector and alarm are built into the car navigation apparatus, and the detector is coupled to a control circuit (not illustrated) of the car navigation apparatus.  
      The operation of the detection device employing light-transmitting touch panel  101  of the present invention is described next, taking an example of employing the detection device of the exemplary embodiment and a display unit in a car navigation apparatus.  
      In the detection device, the capacitance-sensing circuit detects a capacitance between two adjacent surface conductive layers in surface conductive layers  17 A,  17 B,  17 C and  17 D respectively and in turn.  
       FIGS. 3, 5A  and  5 B show the state where the operator sees a display on the car navigation apparatus and moves finger  10  close to area a 3  between surface-conductive layers  17 B and  17 D. When finger  10  is not in proximity, electrostatic capacitance C 3  formed between surface conductive layers  17 B and  17 D is measured between upper right electrode  18 B and lower right electrode  18 D, as shown in  FIG. 5A .  
      Next,  FIG. 5B  shows the state that finger  10  is in proximity to area a 3  at a distance within 15 mm. In this case, a combined capacitance including capacitance C 4  formed between finger  10  and opposing surface conductive layer  17 B and electrostatic capacitance C 5  formed between finger  10  and surface conductive layer  17 D is measured between upper right electrode  18 B and lower right electrode  18 D. Accordingly, whether finger  10  is in proximity to area a 3  is detectable by detecting the change in capacitance between upper right electrode  18 B and lower right electrode  18 D.  
      The sensing circuit then outputs a detection signal to the alarm. The alarm, on receiving this detection signal, generates a “bleep, bleep, bleep!” sound, and light or vibration, etc., simultaneously with the sound. This notifies the operator of the proximity of the finger to area a 3 .  
      When the operator moves a finger close to areas a 1 , a 2  or a 4 , the capacitance-sensing circuit also measures an increase in capacitance between adjacent surface conductive layers in the same way, and detects the proximity of a finger. Then, the detection signal corresponding to the respective area is transmitted to the alarm.  
      For example, as described in the first exemplary embodiment, the alarm makes a “bleep!”, “bleep, bleep!” or “bleep, bleep, bleep, bleep!” sound according to detecting the proximity of a finger to areas a 1 , a 2  or a 4 , and light, vibration, etc., simultaneously with the sound so as to notify the operator.  
      In other words, the operator does not need to visually check the display every time, since the capacitance-sensing circuit detects the proximity of finger and the alarm generates sound, light, vibration, and so on when the operator moves a finger close to the display.  
      Then, for example, if the operator touches any portion in area a 1  with a finger, top substrate  11  dents, and the portion of upper conductive layer  12  corresponding to the touched position lower conductive layer  14 . The voltage ratio-sensing circuit can thus detect when the panel is being touched. In other words, the detector clearly distinguishes between detection of touch and proximity. The voltage ratio-sensing circuit further applies a voltage between upper conductive layer  12  and lower conductive layer  14 , and detects the exact position touched by detecting the voltage ratio in upper conductive layer  12  and in lower conductive layer  14 .  
      Accordingly, if, for example, a display on the display device of the car navigation apparatus in area a 1  is a switch for “highway information,” the operator can confirm that his/her finger is pointing at the area of “highway information” just by confirming the sound such as “bleep!” made when moving the finger close to the surface.  
      After the operator confirms that his/her finger is in proximity to “highway information,” the operator can move the finger closer in the same direction and touch area a 1 . The sensing circuit then detects the portion touched, and transmits a detection signal to the control circuit of the car navigation apparatus. Consequently, for example, the control circuit outputs “highway information” in the form of sound so that the operator can listen to “highway information.” 
       FIGS. 6 and 7  show the third exemplary embodiment of the present invention. Description on the configuration same as the first exemplary embodiment is simplified.  
       FIG. 6  is a sectional view of light-transmitting touch panel  103  in the third exemplary embodiment. As shown in  FIG. 6 , light-transmitting upper conductive layer  32  is formed on the back face of light-transmitting top substrate  31  (equivalent to the first substrate).  
      Upper electrodes (not illustrated) are formed on both ends of this upper conductive layer  32  (equivalent to the second transparent electrode) by printing using conductive paste.  
      Light-transmitting lower conductive layer  34  (equivalent to the third transparent electrode) is formed on the surface of light-transmitting bottom substrate  33  (equivalent to the second substrate).  
      On the surface of this lower conductive layer  34 , lower electrodes (not illustrated) are formed on both ends in a direction perpendicular to the upper electrodes. Dot spacers (not illustrated) are also provided on this face at predetermined intervals so as to secure a predetermined space between lower conductive layer  34  and upper conductive layer  32 .  
      An adhesive layer (not illustrated) made of thermoplastic resin is applied on the front face and back face of frame spacer  36 .  
      Top substrate  31  and bottom substrate  33  are then attached at their peripheries via spacer  36  in such a way that upper conductive layer  32  and lower conductive layer  34  face each other with a predetermined space in between.  
      Light-transmitting surface conductive layers  37 A to  37 D and  39  (equivalent to the first transparent electrode) are formed in a predetermined area on the front face of top substrate  31 .  
       FIG. 7  is a plan view of light-transmitting touch panel  103  seen from the operating side. Comb-like surface conductive layers  37 A to  37 D are formed in predetermined areas at the left, right, top and bottom on the front face of top substrate  31  in such a way that to make a pair with comb-like central surface conductive layer  39  respectively. Upper electrodes  38 A and  38 B, lower electrodes  38 C and  38 D and central electrode  30  made by printing conductive paste are disposed on a part of surface conductive layers  37 A to  37 D and central surface conductive layer  39 . This completes light-transmitting touch panel  103 .  
      A detection device in the third exemplary embodiment includes aforementioned light-transmitting touch panel  103 ; and a detector (not illustrated) configured including a microcomputer and coupled to each electrode of surface-conductive layers  37 A to  37 D and  39 , upper conductive layer  32  and lower conductive layer  34  of light-transmitting touch panel  103 . A capacitance-sensing circuit is coupled between surface-conductive layers  37 A to  37 D and central surface conductive layer  39 . A voltage ratio-sensing circuit is coupled to upper conductive layer  32  and lower conductive player  34 . In addition, an alarm (not illustrated) can be coupled to the detector.  
      The light-transmitting touch panel as configured above is disposed on the surface of a display device of, for example, a car navigation apparatus. The detector and alarm are built into the car navigation apparatus, and the detector is coupled to a control circuit (not illustrated) of the car navigation apparatus.  
      The operation of the detection device employing light-transmitting touch panel  103  of the present invention is described next, taking an example of employing the detection device of the exemplary embodiment and a display unit in a car navigation apparatus.  
      In the detection device, the capacitance-sensing circuit repetitively detects a capacitance between central surface conductive layer  39  and each surface-conductive layers  37 A,  37 B,  37 C and  37 D, in turn.  
      When the operator sees a display on the car navigation apparatus, and moves a finger close to area b 1  where surface conductive layer  37 A and central surface conductive layer  39  are adjacent each other, a capacitor is formed between the finger and a portion of surface conductive layer  37 A and central surface conductive layer  39  facing the finger. A resultant change in capacitance is measured between their upper left electrode  38 A and central electrode  30 . The capacitance-sensing circuit thus detects that the finger is in proximity to area b 1  by comparing with the state that the finger is not in proximity. This detection method is the same as that described in the second exemplary embodiment.  
      The sensing circuit then transmits a detection signal to the alarm. The alarm, on receiving this detection signal generates a “bleep!” sound, for example, and light, vibration, etc., simultaneously with the sound. This notifies the operator of the proximity of the finger to area b 1 .  
      When the operator moves the finger close to areas b 2 , b 3  or b 4 , the capacitance-sensing circuit also detects an increase in capacitance in the same way. The capacitance-sensing circuit detects the proximity of a finger, and the detection signal corresponding to the respective area is transmitted to the alarm.  
      For example, as described in the first exemplary embodiment, the alarm generates “bleep, bleep!,” “bleep, bleep, bleep!,” or “bleep, bleep, bleep, bleep!,” and lighting, vibration, and so on instead of or in addition to these sounds so as to notify the operator.  
      In other words, the operator does not need to visually check the display every time for confirmation, since the sensing circuit detects the proximity position and the alarm generates sound, light, vibration, and so on corresponding to the proximity position when the operator moves a finger close to the surface of the display.  
      Then, when the operator touches any portion in area b 1  with a finger, top substrate  31  dents, and the portion of upper conductive layer  32  corresponding to the touched position contacts lower conductive layer  34 . A voltage ratio-sensing circuit can thus detect when the panel is being touched clearly distinguishing from the proximity of finger  10 . The voltage ratio-sensing circuit further applies a voltage between upper conductive layer  32  and lower conductive layer  34 , and detects the exact position pushed by detecting the voltage ratio in upper conductive layer  32  and in lower conductive layer  34 .  
      In particular, in the third exemplary embodiment, surface conductive layers  37 A to  37 D respectively face central surface conductive layer  39  in a comb shape. This configuration allows detection of proximity to area b 1 , for example, when a finger is in proximity to any border area between surface conductive layer  37 A and central surface conductive layer  39  within area b 1 . This improves operability and reduces erroneous operation.  
      Accordingly, if, for example, a display on the display device of the car navigation apparatus opposing area b 1  is a switch for “map information,” the operator can confirm that his/her finger is pointing at “map information” just by confirming the sound such as “bleep!” made when moving the finger close to the surface.  
      After the operator confirms that his/her finger is pointing at “map information,” the operator can move the finger closer in the same direction and touch area b 1 . The sensing circuit then detects which portion is being touched, and transmits a detection signal to the control circuit of the car navigation apparatus. Consequently, for example, the control circuit outputs “map information” in the form of sound so that the operator can listen to “map information.” 
      As described above, the detection device of the present invention includes the light-transmitting touch panel of the present invention and the detector. The light-transmitting touch panel has one or more divided first transparent electrodes on an operating face of a general touch panel. The detection device includes both proximity sensing circuit for detecting the proximity of a conductive object to the first transparent electrodes and a sensing circuit for detecting a contact of upper and lower electrodes of the touch panel. This configuration offers a detection device that can detect the proximity of a conductive object, such as a finger, from a certain distance, and can also detect the presence of a touch and its position with high accuracy.  
      Still more the present invention can be combined with an alarm which generates sound, light, vibration, and so on. For example, when the operator uses a car navigation apparatus, the detection device detects the proximity of operator&#39;s finger, and the alarm generates sound, light, vibration, and so on. This eliminates the need of visual confirmation. In other words, the present invention can detect the proximity of a conductive object such as a finger from a certain distance, that can also detect the touched position with a high degree of accuracy, and that can clearly distinguish between detection of proximity and touch. Accordingly, the present invention is advantageous for a range of electronic apparatuses.