JP2011039913A - Optical type position detection device and display device with position detection function - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a simply configured optical type position detection device capable of turning on a plurality of light sources for position detection by shifting a timing, and a display device with a position detection function equipped with the optical type position detection device. <P>SOLUTION: In an optical type position detection device 10, a light source driving circuit 50 supplies a drive pulse to a plurality of light sources 12A to 12D for position detection at different timings, and switches the direction of the light intensity distribution of position detection rays of light formed in a detection region 10R. In performing such driving, the drive pulse output from the same drive pulse output terminal 71 of a semiconductor integrated circuit 70 is delayed by a delay circuit 520, and output to the plurality of light sources 12A to 12D for position detection. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an optical position detection device and a display device with a position detection function including the optical position detection device.

  In recent years, electronic devices such as mobile phones, car navigation systems, personal computers, ticket machines, and bank terminals have used display devices with a position detection function in which a touch panel is arranged on the front surface of an image generation device such as a liquid crystal device. The display device with a detection function inputs information while referring to an image displayed on the image generation device. Such a touch panel is configured as a position detection device for detecting the position of the target object in the detection region.

  As a detection method in such a position detection device, a resistance film method, an ultrasonic method, a capacitance method, an optical method, and the like are known. The resistive film method is low in cost but has low transmittance as well as the electrostatic capacity method, and the ultrasonic method and the electrostatic capacity method have a high response speed, but the environment resistance is low. On the other hand, the optical system is characterized in that the environmental resistance, the transmittance, and the response speed can be increased (see Patent Documents 1 and 2).

JP 2004-295644 A JP 2004-303172 A

  However, the optical position detection devices described in Patent Documents 1 and 2 require a number of light sources, photodetectors, and the like corresponding to the resolution of position coordinates to be detected in the vicinity of the display screen. There is a problem.

  Therefore, as schematically shown in FIG. 16, the inventor of the present application forms a light intensity distribution of the position detection light L2 emitted from the position detection light source 12 using the light guide plate 13 or the like, and hits a finger or the like and reflects it. An optical position detection device of a type in which the position detection light L2 is detected by the light detector 15 is examined. Such an optical position detection device has an advantage that only a small number of position detection light sources 12 and photodetectors 15 are required. Further, by shifting the timing when the plurality of position detection light sources 12 are turned on, the intensity distribution of the position detection light L2 emitted from the light guide plate 13 is formed by shifting the timing in the intersecting direction. If this position is detected, a planar coordinate position of a finger or the like can be detected.

  However, in order to shift the timings at which the plurality of position detection light sources 12 are turned on, it is necessary to generate drive pulses corresponding to the number of the position detection light sources 12 while shifting the timings. Since the number of drive pulse output units corresponding to the number needs to be provided in the light source drive circuit, there is a problem that the circuit configuration becomes complicated.

  In particular, when the light source driving circuit is configured in a semiconductor integrated circuit, the number of driving pulse output terminals corresponding to the number of position detection light sources 12 must be provided, which complicates the configuration and reduces the size of the semiconductor integrated circuit. However, there are problems that the cost of the semiconductor integrated circuit can be reduced and the mounting area cannot be reduced.

  In view of the above problems, an object of the present invention is to provide an optical position detection device capable of turning on a plurality of light sources for position detection with a simple configuration at different timings, and such an optical position detection device. Another object is to provide a display device with a position detection function.

  In order to solve the above problems, the present invention is an optical position detection device for optically detecting the position of a target object in a detection region, and emits position detection light irradiated on the target object. A position detection light source device including a plurality of position detection light sources, and a light intensity distribution of the position detection light formed in the detection region by supplying drive pulses to the plurality of position detection light sources at different timings. A light source driving circuit for switching the direction; a photodetector disposed toward the detection region so as to receive the position detection light reflected by the target object; and a detection result and the light intensity distribution in the photodetector. A position detection unit that detects a position of the target object based on the driving pulse output circuit, wherein the light source driving circuit includes a driving pulse output unit that outputs the driving pulse. Delays the outputted the drive pulse from, characterized in that it comprises a delay circuit, the outputs at different timings the driving pulse to the plurality of position detection light source.

  In the present invention, when the position detection light is reflected by the target object, the reflected light is detected by the photodetector. Here, since the intensity of the position detection light in the detection region and the distance from the light source for position detection have a predetermined correlation, the received light intensity obtained via the photodetector and the intensity distribution of the position detection light The position of the target object can be detected based on the above. Therefore, since it is not necessary to arrange a large number of optical elements along the detection region, a position detection device with low cost and low power consumption can be configured. In addition, the light source driving circuit supplies driving pulses to the plurality of position detection light sources at different timings to switch the direction of the light intensity distribution of the position detection light formed in the detection region. Is detected, the position of the target object in each direction can be detected. In addition, the light source drive circuit differs from the configuration in which a plurality of drive pulses are output from each of the plurality of drive pulse output units after forming a plurality of drive pulses with different timings, and the same drive pulse of the drive pulse output circuit The drive pulse output from the output unit is delayed by a delay circuit and output to a plurality of position detection light sources. For this reason, the configuration of the drive pulse output circuit can be simplified even when the plurality of position detection light sources are turned on at different timings.

  The present invention is effective when applied to a case where the light source driving circuit is configured in a semiconductor integrated circuit having a driving pulse output terminal as the driving pulse output unit. According to such a configuration, since the number of drive pulse output terminals of the semiconductor integrated circuit can be reduced, it is possible to reduce the size of the semiconductor integrated circuit, reduce the cost of the semiconductor integrated circuit, and reduce the mounting area.

  In the present invention, it is preferable that the delay circuit is a CR delay circuit in which a capacitor and a resistor are electrically connected between the drive pulse output unit and the position detection light source. According to this configuration, the delay circuit can be configured with relatively inexpensive parts. In addition, since the delay time of the drive pulse can be arbitrarily set only by setting the capacitance value of the capacitor and the resistance value of the resistor to predetermined values, the circuit configuration can be simplified.

  In the present invention, the drive pulse output circuit may employ a configuration including one drive pulse output unit. According to such a configuration, the configuration of the drive pulse output circuit can be most simplified.

  In the present invention, the drive pulse output circuit may include a plurality of drive pulse output units that output the drive pulses at timings shifted from each other as the drive pulse output unit. According to such a configuration, the lighting intervals of the plurality of position detection light sources can be set to an arbitrary condition with a simple configuration.

  In the present invention, the drive pulse output circuit includes a plurality of the drive pulse output units and a timing control unit that controls timing of outputting the drive pulses from the plurality of drive pulse output terminals. May be. According to such a configuration, it is possible to increase the types of lighting patterns with a plurality of position detection light sources with a simple configuration.

  In the present invention, the position detection unit may detect the target object based on a detection result of the photodetector and the light intensity distribution during a period in which a constant current region of the drive pulse is supplied to the position detection light source. It is preferable that a detection period selection unit for detecting the position is provided. According to such a configuration, the position of the target object can be accurately detected even when distortion occurs in the waveform of the drive pulse with the adoption of the delay circuit.

  In the present invention, the light source device for position detection includes a plurality of light incident portions that incorporate the position detection light emitted from the plurality of position detection light sources, and the position detection employed from the light incident portion. It is preferable to include a light guide plate that emits light to the detection region to form the intensity distribution in the detection region. According to such a configuration, the position detection light emitted from the plurality of position detection light sources can be propagated by the light guide plate, whereby the intensity distribution of the position detection light can be formed. Simplification can be achieved.

  The optical position detection device to which the present invention is applied can be used to configure a display device with a position detection function. In this case, the display device with a position detection function includes an image generation device that forms an image in a region overlapping the light guide plate in plan view. As the image generation device, a direct-view display device such as a projection display device, a liquid crystal device, an organic electroluminescence device, or the like can be used.

  The display device with a position detection function according to the present invention is used for electronic devices such as mobile phones, car navigation systems, personal computers, ticket vending machines, and bank terminals, in addition to various display devices.

It is explanatory drawing which shows typically the structure of the display apparatus with a position detection function provided with the optical position detection apparatus and optical position detection apparatus to which this invention is applied. It is explanatory drawing which shows the detailed structure of the optical position detection apparatus to which this invention is applied. It is explanatory drawing of intensity distribution of the position detection light formed with the optical position detection apparatus to which this invention is applied. It is explanatory drawing which shows the electrical constitution of the optical position detection apparatus which concerns on Embodiment 1 of this invention. It is explanatory drawing which shows the specific structure of the light source drive circuit in the optical position detection apparatus which concerns on Embodiment 1 of this invention. It is explanatory drawing which shows the specific structure of the light source drive circuit in the optical position detection apparatus which concerns on Embodiment 2 of this invention. It is explanatory drawing which shows the specific structure of the light source drive circuit in the optical position detection apparatus which concerns on Embodiment 3 of this invention. It is explanatory drawing which shows the specific structure of the light source drive circuit in the optical position detection apparatus which concerns on Embodiment 4 of this invention. It is explanatory drawing of the light source device for position detection used for the optical position detection apparatus which concerns on Embodiment 5 of this invention. It is explanatory drawing which shows the specific structure of the light source drive circuit in the optical position detection apparatus which concerns on Embodiment 5 of this invention. It is a disassembled perspective view of the optical position detection apparatus and optical position detection apparatus which concern on the modification 1 of this invention. It is explanatory drawing which shows the cross-sectional structure of the optical position detection apparatus which concerns on the modification 1 of this invention, and an optical position detection apparatus. It is a disassembled perspective view of the optical position detection apparatus and optical position detection apparatus which concern on the modification 2 of this invention. It is explanatory drawing which shows the cross-sectional structure of the optical position detection apparatus which concerns on the modification 2 of this invention, and an optical position detection apparatus. It is explanatory drawing of the electronic device using the display apparatus with a position detection function which concerns on this invention. It is explanatory drawing which shows the basic composition of an optical position detection apparatus.

  Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Hereinafter, after describing a basic configuration of a position detection device and a display device with a position detection function to which the present invention is applied, each embodiment will be described.

[Basic configuration]
(Overall configuration of position detection device and display device with position detection function)
FIG. 1 is an explanatory diagram schematically showing the configuration of an optical position detection device to which the present invention is applied and a display device with a position detection function provided with the optical position detection device. These are explanatory drawing which shows the example of a structure at the time of using the projection type display apparatus which projects an image from the front (input operation side) with respect to an image projection surface, and back (opposite to the input operation side) with respect to an image projection surface It is explanatory drawing which shows the structural example at the time of using the projection type display apparatus which projects an image from the side.

  A display device with a position detection function 100 shown in FIGS. 1A and 1B includes an optical position detection device 10 and an image generation device 200, and the optical position detection device 10 is operated by the image generation device 200. When a target object such as a finger is brought close to the detection region 10R based on the displayed image, the planar position of the target object Ob is detected.

  As will be described in detail later, the optical position detection device 10 includes a position detection light source device 11 that emits position detection light, and a light detector 15 having a light receiving portion 15a facing the detection region 10R. In this embodiment, the position detection light source device 11 takes in a plurality of position detection light sources 12 that emit position detection light and the position detection light emitted from the position detection light source 12 and emits the light toward the detection region 10R. The light guide plate 13 is provided. Further, the optical position detection device 10 detects the position of the target object based on the light source drive unit (not shown in FIG. 1) for driving the position detection light source 12 and the light reception result of the light detector 15. A position detection unit (not shown in FIG. 1) is provided.

  In the present embodiment, the image generating apparatus 200 is a projection type and has a screen-like projection surface 201 arranged so as to overlap the front surface side (input operation side) of the light guide plate 13. For this reason, the image generation device 200 forms an image in a region overlapping the light guide plate 13 in plan view. In the present embodiment, the image forming region 20R is a region that substantially overlaps the detection region 10R of the optical position detection device 10 and is a horizontally-oriented substantially rectangular shape. Here, the projection surface 201 is made of a material that can transmit infrared light, such as white.

  Among the display devices 100 with position detection function shown in FIGS. 1A and 1B, the image generation device 200 of the display device with position detection function 100 shown in FIG. 1A is an image from the front (input operation side). Is provided. An image generation device 200 of the display device with a position detection function 100 illustrated in FIG. 1B includes a mirror 206 disposed behind the light guide plate 13 and the projection surface 201 (on the side opposite to the input operation side), and a mirror 206. A projection display device 207 that projects an image toward the screen.

(Detailed configuration of the optical position detection device 10)
FIG. 2 is an explanatory diagram showing a detailed configuration of the optical position detection device 10 to which the present invention is applied. FIGS. 2A, 2B, and 2C are sectional views of the optical position detection device 10. FIG. It is explanatory drawing typically shown, explanatory drawing which shows structures, such as a light-guide plate used for the optical position detection apparatus, and explanatory drawing which shows the attenuation state of the infrared rays for position detection in a light-guide plate. FIG. 3 is an explanatory diagram of the intensity distribution of the position detection light formed by the optical position detection device 10 to which the present invention is applied. FIGS. 3A to 3F show a plurality of position detection light sources. It shows how the intensity distribution of the position detection light changes depending on the lighting pattern.

  As shown in FIGS. 2A and 2B, in the position detection light source device 11 used in the optical position detection device 10 of the present embodiment, the light guide plate 13 has a substantially rectangular planar shape. On the side end face 13m of the optical plate 13, the long side portions 13k and 13l face each other, and the short side portions 13i and 13j face each other. Corresponding to the shape of the light guide plate 13, the optical position detection device 10 has four position detection light sources 12A to 12D (position detection light sources 12 shown in FIG. 1) that emit position detection lights L2a to L2d. The light guide plate 13 includes four light incident portions 13a to 13d on which the position detection lights L2a to L2d are incident on the side end surface 13m. The light guide plate 13 includes a light emission surface 13s that emits position detection lights L2a to L2d propagated in the inside on one surface (the upper surface in the drawing), and the light emission surface 13s and the side end surface 13m are orthogonal to each other. . The optical position detection device 10 includes a photodetector 15 having a light receiving portion 15a facing the detection region 10R.

  In the present embodiment, the four position detection light sources 12A to 12D and the four light incident portions 13a to 13d are all provided at the corner portions 13e, 13f, 13g, and 13h of the light guide plate 13. The position detection light sources 12A to 12D are disposed so as to face the light incident portions 13a to 13d, and are preferably disposed in close contact with the light incident portions 13a to 13d. In this embodiment, in addition to the photodetector 15, a compensation photodetector 15x is also used. The compensation photodetector 15x is for compensating the influence of temperature or the like on the detection result obtained through the photodetector 15, and does not detect the position detection lights L2a to L2d.

  The light guide plate 13 is made of a transparent resin plate such as polycarbonate or acrylic resin. In the light guide plate 13, the light output surface 13 s or the back surface 13 t opposite to the light output surface 13 s is provided with a surface uneven structure, a prism structure, a scattering layer (not shown), and the like. Depending on the structure, the light that is incident from the light incident portions 13a to 13d and propagates inside is gradually deflected and emitted from the light exit surface 13s as it travels in the propagation direction. In addition, an optical sheet such as a prism sheet or a light scattering plate may be arranged on the light emitting side of the light guide plate 13 for leveling the position detection lights L2a to L2d as necessary.

  The position detection light sources 12A to 12D are composed of light emitting elements such as LEDs (light emitting diodes), for example, and position detection lights L2a to L2a composed of infrared light according to a drive signal output from a drive circuit (not shown). L2d is emitted as diverging light. The types of the position detection lights L2a to L2d are not particularly limited, but the wavelength distribution may be different from that of visible light, or the light emission form may be different by adding modulation such as blinking. The position detection lights L2a to L2d preferably have a wavelength range that is efficiently reflected by the target object Ob such as a finger or a touch pen. Therefore, if the target object Ob is a human body such as a finger, it is desirable that the infrared ray has a high reflectivity on the surface of the human body (particularly near infrared light close to the visible light region, for example, near 850 nm in wavelength) or 950 nm.

  The position detection light sources 12A to 12D are essentially provided in plural, and are configured to emit the position detection lights L2a to L2d from mutually different positions. Of the four position detection light sources 12A to 12D, the diagonal position detection light sources form a pair to form a first light source, and the other two position detection light sources form a pair to form a second light source. is doing. Of the four position detection light sources 12A to 12D, two adjacent position detection light sources are paired to form a first light source pair, and the other two position detection light sources are paired. A light source pair may be configured.

  The detection region 10R is a planar range in which the position detection lights L2a to L2d are emitted to the viewing side (operation side) and is a planar range in which reflected light from the target object Ob can be generated. In this embodiment, the planar shape of the detection region 10R is a rectangular shape, and the photodetector 15 is disposed at a substantially central portion in the length direction of one long side portion of the four side portions. In the detection region 10 </ b> R, the inner angle of the corner portion of each adjacent side is 90 degrees, and the inner angle is the same as the inner angle of the corner portions 13 e to 13 h of the light guide plate 13.

  In the display device 100 with the position detection function configured as described above, the position detection light L2a and the position detection light L2b are propagated in the opposite directions in the direction indicated by the arrow A inside the light guide plate 13, and the light emission surface 13s. It is emitted from. In addition, the position detection light L2c and the position detection light L2d are emitted from the light emission surface 13s while propagating in directions opposite to each other in a direction intersecting the direction indicated by the arrow A (direction indicated by the arrow B). Therefore, the intensity of the position detection light L2a emitted from the light guide plate 13 to the detection region 10R is linearly attenuated with the distance from the position detection light source 12A, as indicated by a solid line in FIG. Will have a distribution. Further, the light amount of the position detection light L2b emitted to the detection region 10R has an intensity distribution that linearly attenuates with the distance from the position detection light source 12B, as indicated by a dotted line in FIG. become.

  In the display device 100 with a position detection function of this embodiment, the lighting patterns of the four position detection light sources 12A to 12D are sequentially switched, and the direction of the intensity distribution of the position detection light sources is sequentially switched. More specifically, among the four position detection light sources 12A to 12D, the position detection light source 12A is turned on, and as shown in FIG. 3A, the direction indicated by the arrow A in FIG. Form an intensity distribution. Similarly, the position detection light sources 12B, 12C, and 12D are sequentially turned on to form intensity distributions shown in FIGS. 3B, 3C, and 3D. Further, the position detection light sources 12A and 12B are turned on simultaneously to form an intensity distribution in the X-axis direction and the position detection light sources 12B and 12C are turned on simultaneously as shown in FIG. As shown in FIG. 3 (f), an intensity distribution in the X-axis direction opposite to that in FIG. 3 (e) is formed. Furthermore, although not shown, the position detection light sources 12A and 12C are turned on simultaneously to form an intensity distribution in the Y-axis direction, and the position detection light sources 12B and 12D are turned on simultaneously to reverse the Y axis. A direction intensity distribution is formed.

(Basic principle)
A method for acquiring the position information of the target object Ob based on the detection by the photodetector 15 will be described. There are various methods for acquiring the position information. For example, as an example, the ratio of the attenuation coefficients is obtained based on the ratio of the detected light amounts of the two position detection lights, and both are calculated from the ratio of the attenuation coefficients. There is a method of obtaining the position coordinates in the direction connecting two corresponding light sources by obtaining the propagation distance of the position detection light. Further, there is a method in which the difference between the detected light amounts of the two position detection lights is obtained, and the position coordinates in the direction connecting the corresponding two light sources are obtained from the absolute value of the difference. In any of these methods, a method in which the output value from the photodetector 15 is used for calculation as it is, a time until the voltage between the terminals of the capacitor reaches a predetermined voltage after being stored or discharged in the capacitor via the photodetector 15. The method of using for calculation can be mentioned. In either case, the properties described below are used.

  First, in the display device 100 with a position detection function of the present embodiment, the position detection lights L2a to L2d emitted from the position detection light sources 12A to 12D are incident on the inside of the light guide plate 13 from the light incident portions 13a to 13d, respectively. The light is gradually emitted from the light exit surface 13 s while propagating through the light guide plate 13. As a result, the position detection lights L2a to L2d are emitted in a planar shape from the light emission surface 13s.

  For example, the position detection light L2a is gradually emitted from the light exit surface 13s while propagating through the inside of the light guide plate 13 from the light incident part 13a toward the light incident part 13b. Similarly, the position detection lights L2c and L2d are gradually emitted from the light exit surface 13s while propagating through the light guide plate 13. Therefore, when the target object Ob such as a finger is arranged in the detection region 10R, the position detection lights L2a to L2d are reflected by the target object Ob, and a part of the reflected light is detected by the photodetector 15.

  Here, as indicated by a solid line in FIG. 2C, the light amount of the position detection light L2a emitted to the detection region 10R linearly attenuates with the distance from the position detection light source 12A, and the detection region 10R. It is considered that the amount of the position detection light L2b emitted to the line linearly attenuates with the distance from the position detection light source 12B, as indicated by a dotted line in FIG.

Further, the control amount (current amount), conversion coefficient, and emission light amount of the position detection light source 12A are Ia, k, and Ea, and the control amount (current amount), conversion coefficient, and emission light amount of the position detection light source 12B. Is Ib, k, and Eb,
Ea = k · Ia
Eb = k · Ib
It becomes. Further, if the attenuation coefficient and detected light amount of the position detection light L2a are set to fa and Ga, and the attenuation coefficient and detected light amount of the position detection light L2b are set to fb and Gb,
Ga = fa · Ea = fa · k · Ia
Gb = fb · Eb = fb · k · Ib
It becomes.

Therefore, if the photodetector 15 can detect Ga / Gb, which is the ratio of the detected light amounts of both position detection lights,
Ga / Gb = (fa · Ea) / (fb · Eb) = (fa / fb) · (Ia / Ib)
Therefore, if the values corresponding to the emission quantity ratio Ea / Eb and the control quantity ratio Ia / Ib are known, the attenuation coefficient ratio fa / fb is known. For example, if there is a linear relationship between the ratio of the attenuation coefficient and the ratio of the propagation distances of the two position detection lights, the positional information of the target object Ob can be obtained by setting this linear relationship in advance. . Therefore, the position information of the target object Ob in the direction of arrow A can be acquired by driving the position detection light source 12A and the position detection light source 12B in opposite phases. Further, the position information of the target object Ob in the arrow B direction can be acquired by driving the position detection light source 12C and the position detection light source 12D in opposite phases. Therefore, the position coordinate of the target object Ob on the XY plane can be acquired by sequentially performing the detection operation in the A direction and the B direction in the control system.

  When performing position detection in the X-axis direction, for example, the position detection light sources 12A and 12D are driven in phase, the position detection light sources 12B and 12C are driven in phase, and the position detection light sources 12A, 12A, The intensity distribution of the position detection light may be generated in the X-axis direction by driving 12D and the position detection light sources 12B and 12C in opposite phases. Similarly, when performing position detection in the Y-axis direction, the position detection light sources 12A and 12C are driven in the same phase and the position detection light sources 12B and 12D are driven in the same phase at timings different from the position detection in the X axis direction. In addition, the position detection light sources 12A and 12C and the position detection light sources 12B and 12D may be driven in opposite phases to generate an intensity distribution of the position detection light in the Y-axis direction. Even with this method, the position coordinates of the target object Ob on the XY plane can be acquired. In addition, according to the configuration in which a plurality of such position detection light sources are turned on simultaneously, for example, the light / dark gradient distribution of the position detection light can be suitably obtained in a wider range than the configuration in which one position detection light source is turned on. More accurate position detection is possible.

  In acquiring the plane position information in the detection area 10R of the target object Ob based on the light amount ratio of the position detection light detected by the photodetector 15 in this way, for example, a microprocessor unit (MPU) is used as a position detection unit. Thus, it is possible to adopt a configuration in which processing is performed in accordance with execution of predetermined software (operation program). In addition, a configuration in which processing is performed by a position detection unit using hardware such as a logic circuit may be employed. Such a position detection unit may be incorporated as a part of the display device 100 with a position detection function, or may be configured inside an electronic device in which the display device 100 with a position detection function is mounted.

[Embodiment 1]
(Electrical configuration of the optical position detection device 10)
FIG. 4 is an explanatory diagram showing an electrical configuration of the optical position detection device according to the first embodiment of the present invention. FIG. 5 is an explanatory diagram showing a specific configuration of the light source driving circuit 50 in the optical position detection device according to the first embodiment of the present invention. FIGS. 5 (a) and 5 (b) are diagrams illustrating the light source driving circuit 50. FIG. 6 is a timing chart showing the timing of output of drive pulses to position detection light sources 12A to 12D and the like.

  As shown in FIG. 4, the optical position detection device 10 of this embodiment supplies drive pulses to the position detection light source device 11 and the position detection light sources 12A to 12D of the position detection light source device 11 at different timings. The light source driving circuit 50 that switches the direction of the light intensity distribution of the position detection light formed in the detection region 10R, the light detector 15, and the position of the target object based on the detection result and the light intensity distribution in the light detector 15. And a position detection unit 60 for detecting. In this embodiment, the position detection unit 60 includes an XY coordinate detection unit 640, and the XY coordinate detection unit 640 includes an X coordinate detection unit 660 and a Y coordinate detection unit 670.

  As will be described in detail later, the light source driving circuit 50 includes a driving pulse output circuit 510 that outputs a driving pulse (for example, a current pulse), and a timing at which the driving pulse is delayed to the position detection light sources 12A to 12D by delaying the driving pulse. And a delay circuit 520 for outputting. Further, the position detection unit 60 determines the position of the target object Ob based on the detection result and the light intensity distribution in the light detector 15 during the period in which the constant current region of the drive pulse is supplied to the position detection light sources 12A to 12D. A detection period selection unit 630 for detection is provided.

  As shown in FIGS. 4 and 5A, in the optical position detection device 10 of this embodiment, the drive pulse output circuit 510 and the position detection unit 60 are configured in a semiconductor integrated circuit 70 used as a control IC. The delay circuit 520 includes an external circuit provided outside the semiconductor integrated circuit 70. The semiconductor integrated circuit 70 includes only one drive pulse output terminal 71 as a drive pulse output unit for outputting a drive pulse from the drive pulse output circuit 510 to the delay circuit 520. The semiconductor integrated circuit 70 includes a ground terminal 79 for supplying a ground potential to the position detection light source device 11 and two input terminals 77 and 78 to which a detection result of the photodetector 15 is input. . Here, one of the two input terminals 77 and 78 may be used as a ground terminal. In this case, one of the input terminals 77 and 78 may be shared with the ground terminal 79. is there.

  As shown in FIG. 5A, the light source driving circuit 50 includes a driving pulse output circuit 510 configured in the semiconductor integrated circuit 70, and one driving pulse output terminal 71 of the semiconductor integrated circuit 70 (of the driving pulse output circuit 510). Wiring 540 for supplying a drive pulse from the drive pulse output unit) to each anode of the position detection light sources 12A to 12D. The wiring 540 includes a common line 545 extending from the drive pulse output terminal 71 and branch lines 541 to 544 branched from the common line 545 and extending to each of the plurality of position detection light sources 12A to 12D. Further, the light source driving circuit 50 includes a common ground line 590 electrically connected to the cathodes of the position detection light sources 12A to 12D.

  In configuring the delay circuit 520 in the light source driving circuit 50, in this embodiment, the delay circuit 520 is configured as a CR delay circuit, and the CR delay circuit is electrically connected in series to each of the position detection light sources 12A to 12D. A connected CR circuit is provided. The plurality of CR circuits electrically connected to the position detection light sources 12A to 12D are electrically connected in parallel to each other.

More specifically, the branch line 541 to be connected to the position detection light source 12A is CR circuit including a capacitor C ₁₁ and resistor R ₁₁ is electrically connected to the branch line 541, the capacitance of the capacitor C ₁₁ A time constant CR ₁₁ defined by a value obtained by multiplying the value by the resistance value of the resistor R ₁₁ is attached. Similarly, the branch line 542 connected to the position detection light source 12B is CR circuit including a capacitor C ₁₂ and resistor R ₁₂ is electrically connected to the branch line 542, resistor and the capacitance value of the capacitance C ₁₂ A time constant CR ₁₂ defined by a value obtained by multiplying the resistance value of R ₁₂ is attached. In other branch 543, similarly to the branch lines 541 and 542, CR circuit comprising a capacitor C ₁₃ and resistor R _13, and capacitor C ₁₄ and resistor R CR circuit with ₁₄ are electrically connected, the branch line 543 and 544 include a time constant CR ₁₃ defined by a value obtained by multiplying the capacitance value of the capacitor C ₁₃ and the resistance value of the resistor R ₁₃ , the capacitance value of the capacitor C ₁₄ , and the resistance value of the resistor R _14. A time constant CR ₁₄ defined by a value multiplied by is attached. Here, the time constants CR ₁₁ , CR ₁₂ , CR _{13 and} CR ₁₄ have the following relationship: CR ₁₁ <CR ₁₂ <CR ₁₃ <CR ₁₄
There is.

  In the optical position detection apparatus 10 configured in this way, the position detection light sources 12A to 12D shown in FIG. 2B are sequentially turned on, and the intensity of the position detection light shown in FIGS. Distributions are sequentially formed and XY coordinates are detected.

Provisions More specifically, FIG. 5 (a), the (b), the the drive pulse is outputted from a single driving pulse output terminal 71 of the semiconductor integrated circuit 70, the driving pulse, first, by the time constant CR ₁₁ The position detection light source 12A is turned on with a delay, and then turned off. Thereafter, the driving pulse, when after lighting the position detection light sources 12B with a delay defined by a constant CR _12, and turns off. In such a period, the photodetector 15 sequentially detects the position detection lights L2a and L2b reflected by the target object Ob. Then, the XY coordinate detection unit 640 of the position detection unit 60 detects the position of the target object Ob in the A direction shown in FIG. 2B based on the light reception result of the photodetector 15 and the intensity distribution of the position detection light. To do.

Thereafter, the driving pulse, when after lighting the position detection light sources 12C with a delay defined by a constant CR _13, and turns off. Thereafter, the driving pulse, when after lighting the position detection light sources 12D with a delay defined by a constant CR _14, and turns off. In such a period, the photodetector 15 sequentially detects the position detection lights L2c and L2d reflected by the target object Ob. Then, the XY coordinate detection unit 640 of the position detection unit 60 detects the position of the target object Ob in the B direction shown in FIG. 2B based on the light reception result of the photodetector 15 and the intensity distribution of the position detection light. To do.

  Thereafter, in the XY coordinate detection unit 640, the X coordinate detection unit 660 causes the X coordinate of the target object Ob based on the detection result of the position of the target object Ob in the A direction and the detection result of the position of the target object Ob in the B direction. And the Y coordinate detection unit 670 detects the Y coordinate of the target object Ob.

  Here, the drive pulse output from the drive pulse output terminal 71 is a square wave pulse, but the waveform of the drive pulse actually supplied to the position detection light sources 12A to 12D is distorted by the CR circuit of the delay circuit 520. become. However, in this embodiment, the position detection unit 60 detects the target object Ob based on the detection result and the light intensity distribution in the light detector 15 during the period in which the constant current region of the drive pulse is supplied to the position detection light sources 12A to 12D. The detection period selection unit 630 for detecting the position of the detection pulse is used, and the detection result of the photodetector 15 is used only during the period in which the constant current region of the drive pulse is supplied to the position detection light sources 12A to 12D. For example, the detection period selection unit 630 performs masking that applies temporal masking to the detection operation of the photodetector 15 or the detection result of the photodetector 15 based on the signal output from the drive pulse output circuit 510. It can be realized by a circuit or the like.

  In this embodiment, the CR circuit (delay circuit 520) is provided for any of the position detection light sources 12A to 12D. However, the position detection light source 12A that is turned on first is not provided with a CR circuit. The CR circuit (delay circuit 520) may be provided only for the light sources 12B to 12D.

(Main effects of this form)
As described above, in the optical position detection device 10 of the present embodiment, the position detection lights L2a to L2d are emitted from the light emission surface 13s of the light guide plate 13, and this is the target object Ob arranged on the emission side of the light guide plate 13. The reflected light is detected by the photodetector 15. Here, the intensity of the position detection lights L2a to L2d in the detection region 10R and the distance from the position detection light sources 12A to 12D have a predetermined correlation. The light source driving circuit 50 switches the direction of the light intensity distribution of the position detection light formed in the detection region 10R by supplying drive pulses to the plurality of position detection light sources 12A to 12D at different timings. For this reason, the XY coordinates of the target object Ob can be detected from the received light intensity obtained via the photodetector 15 at each timing. Therefore, since it is not necessary to arrange a large number of optical elements along the detection region 10R, the optical position detection device 10 with low cost and low power consumption can be configured.

  Unlike the configuration in which the light source drive circuit 50 outputs a plurality of drive pulses from each of the plurality of drive pulse output units after forming a plurality of drive pulses with different timings, the same drive pulse of the semiconductor integrated circuit 70 is used. The drive pulse output from the output terminal 71 (the same drive pulse output unit of the drive pulse output circuit 510) is delayed by the delay circuit 520 and output to the plurality of position detection light sources 12A to 12D. Therefore, even when the plurality of position detection light sources 12A to 12D are turned on at different timings, the configuration of the drive pulse output circuit 510 can be simplified.

  In particular, in the present embodiment, the present invention is applied when the drive pulse output circuit 510 is configured in the semiconductor integrated circuit 70 provided with the drive pulse output terminal 71. For this reason, since the number of drive pulse output terminals 71 of the semiconductor integrated circuit 70 is one, the semiconductor integrated circuit 70 can be reduced in size, the semiconductor integrated circuit 70 can be reduced in cost, and the mounting area can be reduced. In addition, in this embodiment, the drive pulse output circuit 510 of the semiconductor integrated circuit 70 includes only one drive pulse output terminal 71, so that the configuration can be simplified most.

  The delay circuit 520 is a CR delay circuit in which a capacitor and a resistor are electrically connected between the drive pulse output terminal 71 and the position detection light sources 12A to 12D. Therefore, the delay circuit 520 can be configured with relatively inexpensive parts. In addition, since the delay time of the drive pulse can be arbitrarily set only by setting the capacitance value of the capacitor and the resistance value of the resistor to predetermined values, the circuit configuration can be simplified.

  Further, since the position detection unit 60 includes the detection period selection unit 630, the detection result and light intensity in the photodetector 15 during the period in which the constant current region of the drive pulse is supplied from the position detection light sources 12A to 12D. The position of the target object Ob can be detected based on the distribution. Therefore, the position of the target object Ob can be accurately detected even when the waveform of the rising portion and the falling portion of the drive pulse is distorted with the adoption of the delay circuit 520.

[Embodiment 2]
FIG. 6 is an explanatory diagram showing a specific configuration of the light source driving circuit 50 in the optical position detection device according to the second embodiment of the present invention. Since the basic configuration of this embodiment is the same as that of Embodiment 1, common portions are denoted by the same reference numerals and description thereof is omitted. Further, FIG. 4 is referred to for a basic description of the light source driving circuit 50 and the like.

  As shown in FIGS. 4 and 6, the optical position detection device 10 of the present embodiment also supplies drive pulses to the position detection light sources 12 </ b> A to 12 </ b> D of the position detection light source device 11 at different timings as in the first embodiment. Then, the light source driving circuit 50 that switches the direction of the light intensity distribution of the position detection light formed in the detection region 10R, and the position for detecting the position of the target object based on the detection result of the light detector 15 and the light intensity distribution And a detector 60. The light source driving circuit 50 also includes a driving pulse output circuit 510 that outputs a driving pulse, and a delay circuit 520 that delays the driving pulse and outputs the driving pulse to the position detection light sources 12A to 12D at different timings. . Further, the position detection unit 60 determines the position of the target object Ob based on the detection result and the light intensity distribution in the light detector 15 during the period in which the constant current region of the drive pulse is supplied to the position detection light sources 12A to 12D. A detection period selection unit 630 for detection is provided.

  The drive pulse output circuit 510 and the position detection unit 60 are configured in a semiconductor integrated circuit 70 used as a control IC, and the delay circuit 520 includes an external circuit provided outside the semiconductor integrated circuit 70. The semiconductor integrated circuit 70 includes only one drive pulse output terminal 71 as a drive pulse output unit for outputting a drive pulse from the drive pulse output circuit 510 to the delay circuit 520.

  In this embodiment, the light source driving circuit 50 includes a driving pulse output circuit 510 configured in the semiconductor integrated circuit 70 and one driving pulse output terminal 71 of the semiconductor integrated circuit 70 (a driving pulse output unit of the driving pulse output circuit 510). And a wiring 551 for supplying a drive pulse to the position detection light source 12A. Further, a wiring 552 for supplying a driving pulse to the position detection light source 12B branches from a middle position of the wiring 551, and a driving pulse is supplied from the middle position of the wiring 552 to the position detection light source 12C. The wiring 553 is branched, and a wiring 554 for supplying a drive pulse to the position detection light source 12D is branched from a middle position of the wiring 553.

  In configuring the delay circuit 520 in the light source driving circuit 50, in this embodiment, the delay circuit 520 is configured as a CR delay circuit, and the CR delay circuit is electrically connected in series to each of the position detection light sources 12A to 12D. A connected CR circuit is provided. The plurality of CR circuits electrically connected to the position detection light sources 12A to 12D are in a state of being electrically connected in series with each other.

More specifically, in the wiring 551 connected to the position detection light source 12A, a capacitor C ₁₁ and a resistor R ₁₁ are provided between the drive pulse output terminal 71 and the connection position between the wiring 551 and the wiring 552. A CR circuit is electrically connected, and the wiring 551 has a time constant CR ₁₁ defined by a value obtained by multiplying the capacitance value of the capacitor C ₁₁ and the resistance value of the resistor R ₁₁ . In the wiring 552 connected to the position detection light source 12B, a capacitor C ₁₂ and a resistor R ₁₂ are provided between the connection position of the wiring 551 and the wiring 552 and the connection position of the wiring 552 and the wiring 553. The CR circuit is electrically connected, and the wiring 552 has a time constant CR ₁₂ and a time constant CR ₁₂ defined by a value obtained by multiplying the capacitance value of the capacitor C ₁₂ and the resistance value of the resistor R _12. It is attached. In the wiring 553 connected to the position detection light source 12C, a capacitor C ₁₃ and a resistor R ₁₃ are provided between the connection position between the wiring 552 and the wiring 553 and the connection position between the wiring 553 and the wiring 554. A CR circuit is electrically connected, and the wiring 553 is defined by a value obtained by multiplying the time constant CR ₁₁ , the time constant CR ₁₂ , the capacitance value of the capacitor C ₁₃ and the resistance value of the resistor R _13. A time constant CR ₁₃ is attached. A CR circuit having a capacitor C ₁₄ and a resistor R ₁₄ is electrically connected to the wiring 554 connected to the position detection light source 12D. The wiring 554 includes a time constant CR ₁₁ and a time constant CR ₁₂ . when a constant CR _13, constant CR ₁₄ when it is defined by the resistance value and the value obtained by multiplying the capacitance value and the resistance R ₁₄ of the capacitor C ₁₄ is attached. Here, the time constants CR ₁₁ , CR ₁₂ , CR _{13, and} CR ₁₄ are, for example, the following relationship: CR ₁₁ = CR ₁₂ = CR ₁₃ = CR ₁₄
There is.

  Also in the optical position detection apparatus 10 configured in this manner, as in the first embodiment, the position detection light sources 12A to 12D shown in FIG. 2B are sequentially turned on, and FIGS. Are sequentially formed to detect the XY coordinates. More specifically, as described with reference to FIG. 5B, when a drive pulse is output from one drive pulse output terminal 71 of the semiconductor integrated circuit 70, the drive pulse is output by the delay circuit 520. It is applied to the position detection light sources 12A to 2D while shifting the timing. Accordingly, the position of the target object Ob in the A direction shown in FIG. 2B is detected based on the light reception result of the photodetector 15 and the intensity distribution of the position detection light, and the B direction shown in FIG. 2B. The position of the target object Ob can be detected. Therefore, in the XY coordinate detection unit 640, the X coordinate detection unit 660 performs the X coordinate of the target object Ob based on the detection result of the position of the target object Ob in the A direction and the detection result of the position of the target object Ob in the B direction. And the Y coordinate detection unit 670 detects the Y coordinate of the target object Ob.

  Also in this embodiment, the position detection unit 60 includes the detection period selection unit 630, and the detection result of the photodetector 15 only during the period in which the constant current region of the drive pulse is supplied to the position detection light sources 12A to 12D. Is used.

  In this embodiment, the CR circuit (delay circuit 520) is provided for any of the position detection light sources 12A to 12D. However, the position detection light source 12A that is turned on first is not provided with a CR circuit. The CR circuit (delay circuit 520) may be provided only for the light sources 12B to 12D.

  As described above, also in the optical position detection device 10 of the present embodiment, the light source drive circuit 50 is the same as the drive pulse output terminal 71 of the semiconductor integrated circuit 70 (the same as the drive pulse output circuit 510), as in the first embodiment. The drive pulse output from the drive pulse output unit) is delayed by the delay circuit 520 and output to the plurality of position detection light sources 12A to 12D. Therefore, even when the plurality of position detection light sources 12A to 12D are turned on at different timings, the configuration of the drive pulse output circuit 510 can be simplified. Further, since only one drive pulse output terminal 71 is required for the semiconductor integrated circuit 70, the semiconductor integrated circuit 70 can be downsized, the cost of the semiconductor integrated circuit 70 can be reduced, and the mounting area can be reduced. The same effects as in the first embodiment are obtained.

In this embodiment, the time constants CR ₁₁ , CR ₁₂ , CR _{13, and} CR ₁₄ are, for example, the following relationship: CR ₁₁ = CR ₁₂ = CR ₁₃ = CR ₁₄
Therefore, there is an advantage that capacitors having the same rating can be used as the capacitors C ₁₁ , C ₁₂ , C _13, C ₁₄ and the resistors R ₁₁ , R ₁₂ , R ₁₃ , R ₁₄ .

[Embodiment 3]
FIG. 7 is an explanatory diagram showing a specific configuration of the light source driving circuit 50 in the optical position detection device according to the third embodiment of the present invention. FIGS. 7 (a) and 7 (b) are diagrams illustrating the light source driving circuit 50. FIG. 6 is a timing chart showing the timing of output of drive pulses to position detection light sources 12A to 12D and the like. Since the basic configuration of this embodiment is the same as that of Embodiment 1, common portions are denoted by the same reference numerals and description thereof is omitted. Further, FIG. 4 is referred to for a basic description of the light source driving circuit 50 and the like.

  As shown in FIGS. 4 and 7A, in the optical position detection device 10 of this embodiment, the drive pulses are different from those of the position detection light sources 12A to 12D of the position detection light source device 11 as in the first embodiment. The light source drive circuit 50 that switches the direction of the light intensity distribution of the position detection light that is supplied at the timing and formed in the detection region 10R, and the position of the target object based on the detection result and the light intensity distribution in the light detector 15. And a position detection unit 60 for detection. The light source driving circuit 50 also includes a driving pulse output circuit 510 that outputs a driving pulse, and a delay circuit 520 that delays the driving pulse and outputs the driving pulse to the position detection light sources 12A to 12D at different timings. . Further, the position detection unit 60 determines the position of the target object Ob based on the detection result and the light intensity distribution in the light detector 15 during the period in which the constant current region of the drive pulse is supplied to the position detection light sources 12A to 12D. A detection period selection unit 630 for detection is provided. The drive pulse output circuit 510 and the position detection unit 60 are configured in a semiconductor integrated circuit 70 used as a control IC, and the delay circuit 520 includes an external circuit provided outside the semiconductor integrated circuit 70.

  In this embodiment, the semiconductor integrated circuit 70 has a plurality of drive pulse output terminals, in this embodiment, two drive pulse output terminals, as a drive pulse output section for outputting a drive pulse from the drive pulse output circuit 510 to the delay circuit 520. (A first drive pulse output terminal 72 and a second drive pulse output terminal 73). Here, each of the two drive pulse output terminals (the first drive pulse output terminal 72 and the second drive pulse output terminal 73) outputs a drive pulse at a predetermined timing. In this embodiment, after a drive pulse is output from the first drive pulse output terminal 72 and a predetermined time has elapsed, the drive pulse is output from the second drive pulse output terminal 73.

  In this embodiment, the light source drive circuit 50 supplies a drive pulse to the position detection light source 12A from the drive pulse output circuit 510 configured in the semiconductor integrated circuit 70 and the first drive pulse output terminal 72 of the semiconductor integrated circuit 70. Wiring 561. A wiring 562 for supplying a driving pulse to the position detection light source 12B is branched from the middle position of the wiring 561.

  The light source drive circuit 50 also includes a wiring 563 for supplying a drive pulse from the second drive pulse output terminal 73 of the semiconductor integrated circuit 70 to the position detection light source 12C. Further, a wiring 564 for supplying a driving pulse to the position detection light source 12D is branched from a midway position of the wiring 563.

In configuring the delay circuit 520 in the light source driving circuit 50, in this embodiment, in the wiring 561 connected to the position detection light source 12A, between the connection position of the wiring 561 and the wiring 562 and the position detection light source 12A. Is electrically connected to a CR circuit including a capacitor C ₁₁ and a resistor R ₁₁ , and the wiring 561 is defined by a value obtained by multiplying the capacitance value of the capacitor C ₁₁ and the resistance value of the resistor R _11. A time constant CR ₁₁ is attached. Further, the wiring 562 is connected to the position detection light source 12B is CR circuit including a capacitor C ₁₂ and resistor R ₁₂ is electrically connected to the wiring 562, the resistance and capacitance values of the capacitance C ₁₂ R constant CR ₁₂ is attached when it is prescribed by the value obtained by multiplying the resistance value of _12.

Further, in the wiring 563 connected to the position detection light source 12C, a CR circuit including a capacitor C ₁₃ and a resistor R ₁₃ is electrically connected between the connection position of the wiring 563 and the wiring 564 and the position detection light source 12C. The wiring 563 has a time constant CR ₁₃ defined by a value obtained by multiplying the capacitance value of the capacitor C ₁₃ and the resistance value of the resistor R ₁₃ . Further, the wiring 564 connected to the position detection light source 12D is CR circuit including a capacitor C ₁₄ and resistor R ₁₄ are electrically connected to the wiring 564, the resistance and capacitance values of the capacitance C ₁₄ R A time constant CR ₁₄ defined by a value obtained by multiplying ₁₄ resistance values is attached.

Here, the time constants CR ₁₁ , CR ₁₂ , CR _{13 and} CR ₁₄ have the following relationship: CR ₁₁ <CR ₁₂
CR ₁₃ <CR ₁₄
There is.

  In the optical position detection apparatus 10 configured in this way, the position detection light sources 12A to 12D shown in FIG. 2B are sequentially turned on, and the intensity of the position detection light shown in FIGS. Distributions are sequentially formed and XY coordinates are detected.

Provisions More specifically, in FIG. 7 (a), (b) , when the driving pulse from the first driving pulse output terminal 72 of the semiconductor integrated circuit 70 is output, the driving pulse, first, by the time constant CR ₁₁ The position detection light source 12A is turned on with the delayed time. Thereafter, the driving pulse lights the position detection light sources 12B with a delay defined by the time constant CR _12.

Thereafter, when the driving pulse is outputted from the second driving pulse output terminal 73 of the semiconductor integrated circuit 70, the driving pulse, first, turns on the position detection light sources 12C with a delay defined by the time constant CR _13. Thereafter, the driving pulse, the time constant CR ₁₄ turns on the position detection light sources 12D for position detection with a delay defined by. Accordingly, the position of the target object Ob in the A direction shown in FIG. 2B is detected based on the light reception result of the photodetector 15 and the intensity distribution of the position detection light, and the B direction shown in FIG. 2B. The position of the target object Ob can be detected. Therefore, in the XY coordinate detection unit 640, the X coordinate detection unit 660 performs the X coordinate of the target object Ob based on the detection result of the position of the target object Ob in the A direction and the detection result of the position of the target object Ob in the B direction. And the Y coordinate detection unit 670 detects the Y coordinate of the target object Ob.

  Also in this embodiment, the position detection unit 60 includes the detection period selection unit 630, and the detection result of the photodetector 15 only during the period in which the constant current region of the drive pulse is supplied to the position detection light sources 12A to 12D. Is used.

  In this embodiment, the CR circuit (delay circuit 520) is provided for any of the position detection light sources 12A to 12D. However, the position that is first turned on by the drive pulse output from the first drive pulse output terminal 72 is provided. The detection light source 12A and the position detection light source 12C that is first turned on by the drive pulse output from the second drive pulse output terminal 73 are not provided with a CR circuit, and only the position detection light sources 12B and 12D have a CR circuit (delay). A circuit 520) may be provided.

  As described above, also in the optical position detection device 10 of the present embodiment, the light source drive circuit 50 is the same as the drive pulse output terminal 71 of the semiconductor integrated circuit 70 (the same as the drive pulse output circuit 510), as in the first embodiment. The drive pulse output from the drive pulse output unit) is delayed by the delay circuit 520 and output to the plurality of position detection light sources 12A to 12D. Therefore, even when the plurality of position detection light sources 12A to 12D are turned on at different timings, the configuration of the drive pulse output circuit 510 can be simplified.

  In addition, since the number of drive pulse output terminals of the semiconductor integrated circuit 70 is two, the semiconductor integrated circuit 70 can be downsized, the cost of the semiconductor integrated circuit 70 can be reduced, and the mounting area can be reduced. The same effects as in the first embodiment are obtained.

  Further, since the semiconductor integrated circuit 70 includes two drive pulse output terminals (a first drive pulse output terminal 72 and a second drive pulse output terminal 73), the first drive pulse output terminal 72 and the second drive pulse output are provided. The interval at which the drive pulse is output from the terminal 73 can be arbitrarily set. Therefore, the timing at which the position detection light source 12B is turned on and the timing at which the position detection light source 12C is turned on can be arbitrarily set without being affected by the time constant of the delay circuit 520.

[Embodiment 4]
FIG. 8 is an explanatory diagram showing a specific configuration of the light source driving circuit 50 in the optical position detection device according to the fourth embodiment of the present invention. FIGS. 8 (a) and 8 (b) are diagrams illustrating the light source driving circuit 50. FIG. 6 is a timing chart showing the timing of output of drive pulses to position detection light sources 12A to 12D and the like. Since the basic configuration of this embodiment is the same as that of Embodiments 1 and 3, common portions are denoted by the same reference numerals and description thereof is omitted. Further, FIG. 4 is referred to for a basic description of the light source driving circuit 50 and the like.

  As shown in FIGS. 4 and 8A, in the optical position detection device 10 of this embodiment, the drive pulses are different from those of the position detection light sources 12A to 12D of the position detection light source device 11 as in the first embodiment. The light source drive circuit 50 that switches the direction of the light intensity distribution of the position detection light that is supplied at the timing and formed in the detection region 10R, and the position of the target object based on the detection result and the light intensity distribution in the light detector 15. And a position detection unit 60 for detection. The light source driving circuit 50 includes a driving pulse output circuit 510 that outputs a driving pulse (for example, a current pulse), and a delay circuit that delays the driving pulse and outputs the driving pulse to the position detection light sources 12A to 12D at different timings. 520. Further, the position detection unit 60 determines the position of the target object Ob based on the detection result and the light intensity distribution in the light detector 15 during the period in which the constant current region of the drive pulse is supplied to the position detection light sources 12A to 12D. A detection period selection unit 630 for detection is provided. The drive pulse output circuit 510 and the position detection unit 60 are configured in a semiconductor integrated circuit 70 used as a control IC, and the delay circuit 520 includes an external circuit provided outside the semiconductor integrated circuit 70.

  In this embodiment, the semiconductor integrated circuit 70 has a plurality of drive pulse output terminals, in this embodiment, two drive pulse output terminals, as a drive pulse output section for outputting a drive pulse from the drive pulse output circuit 510 to the delay circuit 520. (A first drive pulse output terminal 74 and a second drive pulse output terminal 75).

  Here, in the drive pulse output circuit 510, a drive pulse generation circuit 511 that generates a drive pulse and a timing control unit 512 are formed. In addition, the timing control unit 512 controls the timing at which the drive pulse is output from the first drive pulse output terminal 74 and the timing at which the drive pulse is output from the second drive pulse output terminal 75. A second timing control unit 514. In this embodiment, as shown in FIG. 8B, under the control of the timing controller 512 (the first timing controller 513 and the second timing controller 514), first, the first drive pulse output terminal 74 and the second After the drive pulse is simultaneously output from the drive pulse output terminal 75, the drive pulse is output again from the first drive pulse output terminal 74, and then the drive pulse is output again from the second drive pulse output terminal 75.

  In this embodiment, the light source drive circuit 50 supplies a drive pulse to the position detection light source 12A from the drive pulse output circuit 510 configured in the semiconductor integrated circuit 70 and the first drive pulse output terminal 74 of the semiconductor integrated circuit 70. A wiring 562 for supplying a drive pulse to the position detection light source 12B is branched from a middle position of the wiring 561. The light source driving circuit 50 includes a wiring 566 for supplying a driving pulse from the second driving pulse output terminal 75 of the semiconductor integrated circuit 70 to the position detection light source 12D. A wiring 567 for supplying a driving pulse to the detection light source 12C is branched.

In configuring the delay circuit 520 in the light source driving circuit 50, in this embodiment, the CR circuit is not connected to the wiring 561 connected to the position detection light source 12A, and the wiring 566 connected to the position detection light source 12C is connected. Similarly to the wiring 561, the CR circuit is not connected. On the other hand, a CR circuit having a capacitor C ₁₂ and a resistor R ₁₂ is electrically connected to the wiring 562 connected to the position detection light source 12B, and the capacitance value of the capacitor C ₁₂ is connected to the wiring 562. And a time constant CR ₁₂ defined by a value obtained by multiplying the resistance value of the resistor R ₁₂ . Further, the wiring 563 is connected to the position detection light source 12C is CR circuit including a capacitor C ₁₃ and resistor R ₁₃ is electrically connected to the wiring 563, the resistance and capacitance values of the capacitance C ₁₃ R A time constant CR ₁₃ defined by a value obtained by multiplying ₁₃ resistance values is attached. Here, the time constants CR ₁₂ and CR ₁₃ have the following relationship: CR ₁₂ = CR ₁₃
There is.

  In the optical position detection device 10 configured as described above, in order to detect the X coordinate, the position detection light sources 12A and 12D shown in FIG. 2B are simultaneously turned on and the intensity distribution shown in FIG. Then, the position detection light sources 12B and 12C are simultaneously turned on to form the intensity distribution shown in FIG. Further, in order to detect the Y coordinate, the position detection light sources 12A to 12D are sequentially turned on to sequentially form the intensity distribution of the position detection light shown in FIGS.

More specifically, in FIGS. 8A and 8B, when a drive pulse is output from the first drive pulse output terminal 74 of the semiconductor integrated circuit 70 in the X coordinate detection step, after lighting the position detection light sources 12A, and turns on the position detection light sources 12B with a delay defined by the time constant CR _12. When a drive pulse is output from the first drive pulse output terminal 74 of the semiconductor integrated circuit 70 and simultaneously, a drive pulse is output from the second drive pulse output terminal 75 of the semiconductor integrated circuit 70, the position of the drive pulse is detected. after lighting the position detection light sources 12C in use the light source 12A and the same timing, and turns on the position detection light sources 12C with a delay defined by the time constant CR _13. Here, the position detection light source 12C is turned on simultaneously with the position detection light source 12B. The X coordinate of the target object Ob is detected based on the light reception result of the light detector 15 at this timing and the intensity distribution of the position detection light.

Next, in the Y coordinate detection step, when a drive pulse is output from the first drive pulse output terminal 74 of the semiconductor integrated circuit 70, the drive pulse turns on the position detection light source 12A and then the time constant CR _12. The position-detecting light source 12B is turned on with a delay defined by. Further, when the drive pulse is output from the second drive pulse output terminal 75 of the semiconductor integrated circuit 70 after the timing at which the drive pulse is output from the first drive pulse output terminal 74 of the semiconductor integrated circuit 70, the drive pulse is , after the position detection light sources 12A is turned off, the position detection light source 12D before the position detection light source 12B is turned again, is lit, then when the position detection light sources 12C with a delay defined by a constant CR ₁₃ Light up. Here, the position detection light source 12C is turned on after the position detection light source 12B is turned off. The Y coordinate of the target object Ob is detected based on the light reception result of the light detector 15 at this timing and the intensity distribution of the position detection light. The detection of the Y coordinate may use the timing at which the position detection light sources 12A and 12B are turned on or the timing at which the position detection light sources 12C and 12D are turned on.

  Also in this embodiment, the position detection unit 60 includes the detection period selection unit 630, and the detection result of the photodetector 15 only during the period in which the constant current region of the drive pulse is supplied to the position detection light sources 12A to 12D. Is used.

  As described above, also in the optical position detection device 10 of the present embodiment, the light source drive circuit 50 is the same as the drive pulse output terminal 71 of the semiconductor integrated circuit 70 (the same as the drive pulse output circuit 510), as in the first embodiment. The drive pulse output from the drive pulse output unit) is delayed by the delay circuit 520 and output to the plurality of position detection light sources 12A to 12D. Therefore, even when the plurality of position detection light sources 12A to 12D are turned on at different timings, the configuration of the drive pulse output circuit 510 can be simplified. In addition, since the number of drive pulse output terminals of the semiconductor integrated circuit 70 is two, the semiconductor integrated circuit 70 can be downsized, the cost of the semiconductor integrated circuit 70 can be reduced, and the mounting area can be reduced. The same effects as in the first embodiment are obtained.

  Further, the semiconductor integrated circuit 70 (drive pulse output circuit 510) includes two drive pulse output terminals (a first drive pulse output terminal 74 and a second drive pulse output terminal 75), and is driven from the drive pulse output terminals. The timing for outputting the pulse can be arbitrarily set by the timing control unit 512. For this reason, it is possible to increase the types of lighting patterns in the plurality of position detection light sources 12A to 12D with a simple configuration.

[Embodiment 5]
FIG. 9 is an explanatory diagram of the position detection light source device 11 used in the optical position detection device according to the fifth embodiment of the present invention. FIG. 10 is an explanatory diagram showing a specific configuration of the light source driving circuit 50 in the optical position detection device according to the fifth embodiment of the present invention. FIGS. 10 (a) and 10 (b) are diagrams illustrating the light source driving circuit 50. FIG. 6 is a timing chart showing the timing of output of drive pulses to position detection light sources 12A to 12D and the like. Since the basic configuration of this embodiment is the same as that of Embodiment 1, common portions are denoted by the same reference numerals and description thereof is omitted. Further, FIG. 4 is referred to for a basic description of the light source driving circuit 50 and the like.

  In the present embodiment, as described below, the semiconductor integrated circuit 70 has one drive pulse output terminal. However, in order to detect the X coordinate, the position detection light sources 12A and 12D shown in FIG. After the light is simultaneously turned on to form the intensity distribution shown in FIG. 3E, the position detection light sources 12B and 12C are turned on simultaneously to form the intensity distribution shown in FIG. In order to detect the Y coordinate, the position detection light sources 12A and 12C shown in FIG. 2B are simultaneously turned on to form an intensity distribution in the Y-axis direction, and then the position detection light sources 12B and 12D are turned on simultaneously. Thus, an inverse intensity distribution in the Y-axis direction is formed.

  As shown in FIG. 9, in the optical position detection device 10 and the display device 100 with a position detection function of the present embodiment, the light guide plate 13 includes four corner portions (corner portions 13e, 13f, 13g, and 13h). One light incident part (light incident part 13a, 13b, 13c, 13d) is formed, and one light source for position detection (position detection light sources 12A, 12B, 12C, 12D) is provided in each of the light incident parts. Is provided.

  In this embodiment, the four light incident portions 13a, 13b, 13c, and 13d are connected to the first light incident portions 131a, 131b, 131c, and 131d provided on the long side portions 13k and 13i of the light guide plate 13, respectively. Second light incident portions 132a, 132b, 132c, 132d provided on the short side portion side of the optical plate 13 are provided. Corresponding to the structure of the light incident portions 13a, 13b, 13c, and 13d, the position detection light sources 12A, 12B, 12C, and 12D each have position detection light toward the first light incident portions 131a, 131b, 131c, and 131d. First position detection light sources 121A, 121B, 121C, 121D and second position detection light sources 122A, 122B, 122C that emit position detection light toward the second light incident portions 132a, 132b, 132c, 132d. , 122D. Here, the first position detection light sources 121A, 121B, 121C, and 121D have their center optical axes perpendicular to the first light incident portions 131a, 131b, 131c, and 131d, and the second position detection light sources 122A and 122B. , 122C, 122D have the central optical axis oriented perpendicularly to the second light incident portions 132a, 132b, 132c, 132d.

  In the optical position detection apparatus 10 configured as described above, in order to detect the X coordinate, the first position detection light sources 121A and 121D and the second position detection light sources 122A and 122D are driven in the same phase to detect the first position. The light sources 121B and 121B and the second position detection light sources 122B and 122C are driven in phase. At that time, the first position detection light sources 121A and 121D and the second position detection light sources 122A and 122D, and the first position detection light sources 121B and 121B and the second position detection light sources 122B and 122C are driven in opposite phases. . In this way, an intensity distribution of the position detection light is generated in the X direction of the light guide plate 13 (detection region 10R). In order to detect the Y coordinate, the first position detection light sources 121A and 121C and the second position detection light sources 122A and 122C are driven in the same phase at a timing different from the detection of the X coordinate, and the first position detection light source is detected. 121B and 121D and the second position detection light sources 122B and 122D are driven in phase. At that time, the first position detection light sources 121A and 121C and the second position detection light sources 122A and 122C, and the first position detection light sources 121B and 121D and the second position detection light sources 122B and 122D are driven in opposite phases. . In this way, the intensity distribution of the position detection light is generated in the Y direction of the light guide plate 13 (detection region 10R).

  In realizing this driving method, in this embodiment, as shown in FIGS. 4 and 10A, the optical position detection device 10 detects the position of the position detection light source device 11 in substantially the same manner as in the first embodiment. A light source driving circuit 50 that supplies driving pulses to the light sources 12A to 12D at different timings, and a position detection unit 60 that detects the position of the target object based on the detection result of the light detector 15 and the light intensity distribution. ing. The light source driving circuit 50 also includes a driving pulse output circuit 510 that outputs a driving pulse, and a delay circuit 520 that delays the driving pulse and outputs the driving pulse to the position detection light sources 12A to 12D at different timings. . Further, the position detection unit 60 determines the position of the target object Ob based on the detection result and the light intensity distribution in the light detector 15 during the period in which the constant current region of the drive pulse is supplied to the position detection light sources 12A to 12D. A detection period selection unit 630 for detection is provided.

  The drive pulse output circuit 510 and the position detection unit 60 are configured in a semiconductor integrated circuit 70 used as a control IC, and the delay circuit 520 includes an external circuit provided outside the semiconductor integrated circuit 70. The semiconductor integrated circuit 70 includes only one drive pulse output terminal 71 as a drive pulse output unit for outputting a drive pulse from the drive pulse output circuit 510 to the delay circuit 520.

  In this embodiment, the light source driving circuit 50 includes a driving pulse output circuit 510 configured in the semiconductor integrated circuit 70 and one driving pulse output terminal 71 (the driving pulse output circuit 510) of the semiconductor integrated circuit 70, as in the first embodiment. And a wiring 540 for supplying a drive pulse to each of the position detection light sources 12A to 12D. The wiring 540 includes a common line 545 extending from the drive pulse output terminal 71 and branch lines 541 to 544 branched from the common line 545 and extending to each of the plurality of position detection light sources 12A to 12D. In this embodiment, the anodes of the second position detection light sources 122A and 122D are electrically connected to the branch line 541, and the anodes of the second position detection light sources 122B and 122C are electrically connected to the branch line 542. The anodes of the first position detection light sources 121A and 121C are electrically connected to the branch line 543, and the anodes of the first position detection light sources 121B and 121D are electrically connected to the branch line 544.

In constituting the delay circuit 520 in such a light source driving circuit 50, in this embodiment, the second position detection light sources 122A, the branch line 541 to be connected to 122D, CR circuits electrically with the capacitor C ₁₁ and resistor R ₁₁ The branch line 541 has a time constant CR ₁₁ defined by a value obtained by multiplying the capacitance value of the capacitor C ₁₁ and the resistance value of the resistor R ₁₁ . Similarly, the branch line 542 which connects the second position detecting light source 122B, a 122C, CR circuit including a capacitor C ₁₂ and resistor R ₁₂ is electrically connected to the branch line 542, the electrostatic capacity C ₁₂ constant CR ₁₂ is attached when it is prescribed by the value obtained by multiplying the resistance value of the capacitance value and the resistance R _12. A CR circuit having a capacitor C ₁₃ and a resistor R ₁₃ is electrically connected to the branch line 543 connected to the first position detection light sources 121A and 121C, and an electrostatic capacity of the capacitor C ₁₃ is connected to the branch line 543. A time constant CR ₁₃ defined by a value obtained by multiplying the value by the resistance value of the resistor R ₁₃ is attached. The first position detection light sources 121B, the branch line 544 which connects to 121D is CR circuit including a capacitor C ₁₄ and resistor R ₁₄ is electrically connected to the branch line 544, the capacitance of the capacitor C ₁₄ A time constant CR ₁₄ defined by a value obtained by multiplying the value by the resistance value of the resistor R ₁₄ is attached. Here, the time constants CR ₁₁ , CR ₁₂ , CR _{13 and} CR ₁₄ have the following relationship: CR ₁₁ <CR ₁₂ <CR ₁₃ <CR ₁₄
There is.

In the optical position detection apparatus 10 configured as described above, when the drive pulses from one drive pulse output terminal 71 of the semiconductor integrated circuit 70 is output, the driving pulse, first, with a delay defined by the time constant CR ₁₁ The second position detection light sources 122A and 122D are turned on. Thereafter, the driving pulse, the second position detection light sources 122B with a delay defined by the time constant CR _12, to light the 12C. In such a period, the photodetector 15 sequentially detects the position detection light reflected by the target object Ob. Then, the X coordinate detection unit 660 of the position detection unit 60 detects the X coordinate of the target object Ob based on the light reception result of the photodetector 15 and the intensity distribution of the position detection light.

Thereafter, the driving pulse, the first position detection light sources 121A with a delay defined by the time constant CR _13, and turns on the 121C. Thereafter, the driving pulse, the first position detection light sources 121B with a delay defined by the time constant CR _14, and turns on the 121D. In such a period, the photodetector 15 sequentially detects the position detection light reflected by the target object Ob. Then, the Y coordinate detection unit 670 of the position detection unit 60 detects the Y coordinate of the target object Ob based on the light reception result by the photodetector 15 and the intensity distribution of the position detection light.

  As described above, also in the optical position detection device 10 of the present embodiment, the light source drive circuit 50 is the same as the drive pulse output terminal 71 of the semiconductor integrated circuit 70 (the same as the drive pulse output circuit 510), as in the first embodiment. The drive pulse output from the drive pulse output unit) is delayed by the delay circuit 520 and output to the plurality of position detection light sources 12A to 12D. Therefore, even when the plurality of position detection light sources 12A to 12D are turned on at different timings, the configuration of the drive pulse output circuit 510 can be simplified.

  In addition, since only one drive pulse output terminal is required for the semiconductor integrated circuit 70, the semiconductor integrated circuit 70 can be downsized, the cost of the semiconductor integrated circuit 70 can be reduced, and the mounting area can be reduced. The same effects as in the first embodiment are obtained.

(Other embodiments)
The optical position detection device 10 and the display device 100 with a position detection function of the present invention are not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention. It is. For example, in the above embodiment, only one photodetector 15 is provided, but another photodetector may be disposed at an appropriate position.

[Modification of Display Device 100 with Position Detection Function]
In the above embodiment, the projection display devices 203 and 207 are provided as the image generation device 200. However, as shown in FIGS. 11 to 14, a direct-view display device is employed as the image generation device 200. Then, it can be used for an electronic device described later with reference to FIG.

(Modification 1 of the display device 100 with a position detection function)
FIGS. 11 and 12 are an exploded perspective view and an explanatory view showing a cross-sectional configuration of the optical position detection device 10 and the display device 100 with a position detection function according to the first modification of the present invention. In addition, in the display device 100 with a position detection function of the present embodiment, the configuration of the optical position detection device 10 is the same as that of the above-described embodiment. Omitted.

  The display device 100 with a position detection function shown in FIGS. 11 and 12 includes an optical position detection device 10 and an image generation device 200. The optical position detection device 10 is for position detection that emits position detection light. The light source 12, the light guide plate 13, and the photodetector 15 having the light receiving portion 15a facing the detection region 10R are provided. The image generation device 200 is a direct-view display device 208 such as an organic electroluminescence device or a plasma display device, and is provided opposite to the input operation side with respect to the optical position detection device 10. The direct-view display device 208 includes an image display region 20R in a region overlapping the light guide plate 13 in plan view, and the image display region 20R overlaps with the detection region 10R in plan view.

(Modification 2 of the display device 100 with a position detection function)
FIGS. 13 and 14 are explanatory diagrams of the optical position detection device 10 and the display device 100 with a position detection function according to the second modification of the present invention, and FIGS. 13 and 14 respectively show the optical position detection device 10 and the optical position detection device 10. It is explanatory drawing which shows the disassembled perspective view of the display apparatus with a position detection function 100, and a cross-sectional structure. In addition, in the display device 100 with a position detection function of the present embodiment, the configuration of the optical position detection device 10 is the same as that of the above-described embodiment. Omitted.

  A display device with a position detection function 100 shown in FIGS. 13 and 14 includes an optical position detection device 10 and an image generation device 200. The optical position detection device 10 is for position detection that emits position detection light. The light source 12, the light guide plate 13, and the photodetector 15 having the light receiving portion 15a facing the detection region 10R are provided. The image generation device 200 includes a liquid crystal device 209 that is a direct-view display device. The liquid crystal device 209 includes an image display region 20R in a region overlapping the light guide plate 13 in plan view, and the image display region 20R overlaps with the detection region 10R in plan view.

  In the display device with a position detection function 100 according to the present embodiment, an optical sheet 16 for leveling the position detection lights L2a to L2d is arranged on the light emitting side of the light guide plate 13 as necessary. In this embodiment, as the optical sheet 16, the first prism sheet 161 facing the light exit surface 13s of the light guide plate 13 is opposed to the first prism sheet 161 on the side opposite to the side where the light guide plate 13 is located. A second prism sheet 162 and a light scattering plate 163 facing the second prism sheet 162 on the side opposite to the side where the light guide plate 13 is located are used. A light shielding sheet 17 having a rectangular frame shape is disposed around the optical sheet 16 on the side opposite to the side where the light guide plate 13 is located with respect to the optical sheet 16. The light shielding sheet 17 prevents the position detection lights L2a to L2d emitted from the position detection light sources 12A to 12D from leaking.

  The liquid crystal device 209 (the image generation device 200) includes a liquid crystal panel 209a on the opposite side of the optical sheet 16 (the first prism sheet 161, the second prism sheet 162, and the light scattering plate 163) from the side where the light guide plate 13 is located. It has. In this embodiment, the liquid crystal panel 209a is a transmissive liquid crystal panel, and has a structure in which two light-transmitting substrates 21 and 22 are bonded together with a sealing material 23 and a liquid crystal 24 is filled between the substrates. A translucent cover 30 is provided on the liquid crystal panel 209a. In this embodiment, the liquid crystal panel 209a is an active matrix liquid crystal panel, and on one side of the two light transmissive substrates 21 and 22, a light transmissive pixel electrode, a data line, a scanning line, and a pixel switching element (see FIG. (Not shown) is formed, and a translucent common electrode (not shown) is formed on the other side. Note that the pixel electrode and the common electrode may be formed on the same substrate. In the liquid crystal panel 209a, when a scanning signal is output to each pixel through the scanning line and an image signal is output through the data line, the orientation of the liquid crystal 24 is controlled in each of the plurality of pixels. An image is formed in the image display area 20R.

  In the liquid crystal panel 209a, one translucent substrate 21 is provided with a substrate overhanging portion 21t that projects from the outer shape of the other translucent substrate 22 to the periphery. An electronic component 25 constituting a drive circuit or the like is mounted on the surface of the substrate overhanging portion 21t. In addition, a wiring member 26 such as a flexible wiring board (FPC) is connected to the board protruding portion 21t. Note that only the wiring member 26 may be mounted on the substrate overhanging portion 21t. In addition, a polarizing plate (not shown) is arrange | positioned at the outer surface side of the translucent board | substrates 21 and 22 as needed.

  Here, in order to detect the planar position of the target object Ob, it is necessary to emit the position detection lights L2a to L2d to the viewing side where the operation by the target object Ob is performed. The liquid crystal panel 209a includes the light guide plate 13 and the optical It is arranged closer to the viewing side (operation side) than the sheet 16. Therefore, in the liquid crystal panel 209a, the image display region 20R is configured to be able to transmit the position detection lights L2a to L2d. When the liquid crystal panel 209a is arranged on the side opposite to the viewing side of the light guide plate 13, the image display region 20R does not need to be configured to transmit the position detection lights L2a to L2d. Instead, the image display area 20 </ b> R needs to be configured to be seen through from the viewing side through the light guide plate 13.

  The liquid crystal device 209 includes an illumination device 40 for illuminating the liquid crystal panel 209a. In this embodiment, the illuminating device 40 is disposed between the light guide plate 13 and the reflection plate 14 on the side opposite to the side where the liquid crystal panel 209a is located with respect to the light guide plate 13. The illumination device 40 includes an illumination light source 41 and an illumination light guide plate 43 that emits the illumination light emitted from the illumination light source 41 while propagating the illumination light. The illumination light guide plate 43 has a rectangular planar shape. It has. The illumination light source 41 is composed of a light emitting element such as an LED (light emitting diode), for example, and emits, for example, white illumination light L4 in accordance with a drive signal output from a drive circuit (not shown). In this embodiment, a plurality of illumination light sources 41 are arranged along the side portion 43 a of the illumination light guide plate 43.

  The light guide plate 43 for illumination is provided with an inclined surface 43g on the surface portion on the light emission side adjacent to the side portion 43a (the outer peripheral portion of the light emission surface 43s on the side portion 43a side). The thickness gradually increases toward 43a. With the light incident structure having the inclined surface 43g, the height of the side portion 43a is made to correspond to the height of the light emitting surface of the illumination light source 41 while suppressing an increase in the thickness of the portion where the light emitting surface 43s is provided. is there.

  In such an illuminating device 40, the illumination light emitted from the illumination light source 41 enters the illumination light guide plate 43 from the side portion 43 a of the illumination light guide plate 43, and then the inside of the illumination light guide plate 43 on the opposite side. It propagates toward the outer edge 43b of the light and is emitted from the light exit surface 43s which is one surface. Here, the light guide plate 43 for illumination has a light guide structure in which the light amount ratio of the emitted light from the light emitting surface 43s to the internally propagated light monotonously increases from the side portion 43a side to the outer edge portion 43b on the opposite side. ing. Such a light guide structure is, for example, an area of a fine concavo-convex refracting surface for light deflection or light scattering formed on the light exit surface 43 s or the back surface 43 t of the light guide plate 43 for illumination, and the printed scattering layer. This is realized by gradually increasing the formation density and the like toward the internal propagation direction. By providing such a light guide structure, the illumination light L4 incident from the side portion 43a is emitted substantially uniformly from the light emission surface 43s.

  In the present embodiment, the illumination light guide plate 43 is disposed on the opposite side to the viewing side of the liquid crystal panel 209a so as to overlap the image display region 20R of the liquid crystal panel 209a in a planar manner, and functions as a so-called backlight. However, the illumination light guide plate 43 may be arranged on the viewing side of the liquid crystal panel 209a so as to function as a so-called front light. In this embodiment, the illumination light guide plate 43 is disposed between the light guide plate 13 and the reflection plate 14. However, the illumination light guide plate 43 may be disposed between the optical sheet 16 and the light guide plate 13. Good. Moreover, you may comprise the light guide plate 43 for illumination and the light guide plate 13 as a common light guide plate. In this embodiment, the optical sheet 16 is shared between the position detection lights L2a to L2d and the illumination light L4. However, a dedicated optical sheet different from the optical sheet 16 may be disposed on the light emitting side of the light guide plate 43 for illumination. This is because the illumination light guide plate 43 often uses a light scattering plate exhibiting a sufficient light scattering action for the purpose of equalizing the planar luminance of the illumination light L4 emitted from the light emission surface 43s. In the position detection light guide plate 13, if the position detection lights L2a to L2d emitted from the light exit surface 13s are greatly scattered, the position detection is hindered. For this reason, it is necessary to use a light scattering plate that does not have a light scattering plate, or to use a light scattering plate that exhibits a relatively light light scattering action. . However, optical sheets having a condensing function such as prism sheets (first prism sheet 161 and second prism sheet 162) may be shared.

(Example of mounting on electronic equipment)
With reference to FIG. 15, an electronic apparatus to which the display device with a position detection function 100 described with reference to FIGS. 11 to 14 is applied will be described. FIG. 15 is an explanatory diagram of an electronic apparatus using the display device with a position detection function according to the present invention. FIG. 15A illustrates a configuration of a mobile personal computer including the display device 100 with a position detection function. The personal computer 2000 includes a display device 100 with a position detection function as a display unit and a main body 2010. The main body 2010 is provided with a power switch 2001 and a keyboard 2002. FIG. 15B shows a configuration of a mobile phone including the display device 100 with a position detection function. The cellular phone 3000 includes a plurality of operation buttons 3001, scroll buttons 3002, and the display device 100 with a position detection function as a display unit. By operating the scroll button 3002, the screen displayed on the display device with a position detection function 100 is scrolled. FIG. 15C shows the configuration of a personal digital assistant (PDA) to which the display device 100 with a position detection function is applied. The information portable terminal 4000 includes a plurality of operation buttons 4001, a power switch 4002, and the display device 100 with a position detection function as a display unit. When the power switch 4002 is operated, various types of information such as an address book and a schedule book are displayed on the display device 100 with a position detection function.

  Note that the electronic apparatus to which the display device 100 with a position detection function is applied includes, in addition to those shown in FIG. 15, a digital still camera, a liquid crystal television, a viewfinder type, a monitor direct view type video tape recorder, a car navigation device, a pager, Examples include electronic notebooks, calculators, word processors, workstations, video phones, POS terminals, bank terminals, and other electronic devices. And the display apparatus 100 with a position detection function mentioned above is applicable as a display part of these various electronic devices.

10 .... Optical position detection device, 10R ... Detection area, 12A, 12B, 12C, 12D ... Light source for position detection, 13 .... Light guide plate, 15 .... Photo detector, 15a ... Light receiving part, 50 ... · Light source drive circuit, 60 ·· Position detector, 70 · · Semiconductor integrated circuit, 71 · · Drive pulse output terminal, 72, 74 · · First drive pulse output terminal (drive pulse output portion), 73, 75 · · Second drive pulse output terminal (drive pulse output unit), 100 ... display device with position detection function, 200 ... image generating device, 510 ... drive pulse output circuit, 512 ... timing control unit, 520 ... delay circuit , L2a, L2b, L2c, L2d ... Position detection light

Claims (9)

An optical position detection device for optically detecting the position of a target object in a detection region,
A position detection light source device comprising a plurality of position detection light sources for emitting position detection light applied to the target object;
A light source driving circuit that supplies driving pulses to the plurality of position detection light sources at different timings to switch the direction of the light intensity distribution of the position detection light formed in the detection region;
A photodetector arranged toward the detection region to receive the position detection light reflected by the target object;
A position detection unit for detecting the position of the target object based on the detection result of the photodetector and the light intensity distribution;
Have
The light source drive circuit includes a drive pulse output circuit that includes a drive pulse output unit that outputs the drive pulse, and delays the drive pulse output from the same drive pulse output unit so that the drive pulse is output to the plurality of drive pulses. And a delay circuit that outputs the position detection light source at different timings.   The optical position detection device according to claim 1, wherein the light source driving circuit is configured in a semiconductor integrated circuit including a driving pulse output terminal as the driving pulse output unit.   The optical system according to claim 1, wherein the delay circuit is a CR delay circuit in which a capacitor and a resistor are electrically connected between the drive pulse output unit and the position detection light source. Position detection device.   4. The optical position detection device according to claim 1, wherein the drive pulse output circuit includes one drive pulse output unit. 5.   4. The drive pulse output circuit includes a plurality of drive pulse output units that output the drive pulses at timings shifted from each other as the drive pulse output unit. 5. An optical position detection apparatus according to 1.   2. The drive pulse output circuit includes a plurality of the drive pulse output units and a timing control unit that controls timing of outputting the drive pulses from the plurality of drive pulse output terminals. 4. The optical position detection device according to any one of items 1 to 3.   The position detection unit detects the position of the target object based on a detection result of the photodetector and the light intensity distribution during a period in which a constant current region of the drive pulse is supplied to the position detection light source. The optical position detection apparatus according to claim 1, further comprising a detection period selection unit for detecting the position.   The position detection light source device includes a plurality of light incident portions that incorporate the position detection light emitted from the plurality of position detection light sources, and the position detection light that is captured from the light incidence portions. The optical position according to claim 1, further comprising: a light guide plate that emits to a region and forms the intensity distribution in the detection region. Detection device. A display device with a position detection function, comprising the optical position detection device according to any one of claims 1 to 8,
A display device with a position detection function, comprising: an image generation device that forms an image in a region overlapping the light guide plate in plan view.