JP5609581B2 - Optical position detection device and device with position detection function - Google Patents

Description

  The present invention relates to an optical position detection device that optically detects the position of a target object, and a device with a position detection function that includes the optical position detection device.

  As an optical position detection device that optically detects a target object, for example, detection light that is emitted from each of a plurality of light sources for detection toward the target object via a transparent member and reflected by the target object Has been proposed that is transmitted through a translucent member and detected by a photodetector. In the optical position detection device having such a configuration, the position of the target object is detected based on the detection result of the detection light by the photodetector (see, for example, Patent Document 1).

  In addition, a light guide plate is provided in the optical position detection device, and the detection light emitted from each of the plurality of detection light sources is emitted toward the target object through the light guide plate, and the detection light reflected by the target object is emitted as light. A method of detecting with a detector has also been proposed (see Patent Documents 2 and 3).

Special Table 2003-534554 JP 2010-127671 A JP 2009-295318 A

  In this type of optical position detection device, in addition to the detection light source, a reference light source for allowing the reference light to enter the photodetector without passing through the detection light emission space (detection target space) is provided. If the position of the target object is detected based on the detection intensity of the reference light emitted from the light detector and the detection intensity of the detection light at the light detector, the target object is not affected by environmental light. The position can be detected. In addition, if a common drive signal is applied to the detection light source and the reference light source, the position of the target object can be detected without being affected by fluctuations in the intensity of the drive signal.

  However, when the photodetector and the reference light source are arranged at different positions, the reference light emitted from the reference light source may leak into the detection light emission space. In such a case, the light is reflected by the target object. Since the reference light thus incident also enters the photodetector, there is a problem that the detection intensity of the reference light at the photodetector varies. On the other hand, when the photodetector and the reference light source are brought close to each other to prevent the reference light emitted from the reference light source from leaking into the detection light emission space, the distance between the photodetector and the reference light source is If it is too short, the detection intensity of the reference light at the photodetector will be excessively high. As a result, the detection intensity of the detection light at the photodetector becomes relatively lower than the detection intensity of the reference light at the photodetector, and the sensitivity when detecting the position of the target object is reduced. There is a point.

  In view of the above problems, an object of the present invention is to prevent the reference light emitted from the reference light source from leaking into the detection light emission space, while increasing the detection intensity of the reference light source in the photodetector. An object of the present invention is to provide an optical position detection device that can be suppressed to an appropriate level, and a device with a position detection function including the optical position detection device.

  In order to solve the above problems, the present invention is an optical position detection device that optically detects the position of a target object, and a plurality of detection light sources that emit detection light, and the detection light is emitted. A light detector for detecting the detection light reflected by the target object located in the detection light emission space; a reference light source for causing reference light to enter the light detector without passing through the detection light emission space; Of the target object in the detection light emission space based on the detection intensity of the detection light at the photodetector when the detection light sources are sequentially turned on and the detection intensity of the reference light at the photodetector The position detection unit for detecting the position, the photodetector and the reference light source constitute a light receiving unit held in a common unit case, and the light receiving unit emits light from the reference light source. Reference above And wherein the to be incident on the photodetector in a state with reduced strength.

  In the present invention, since the reference light source is provided, the position of the target object can be detected using the reference light emitted from the reference light source. Therefore, the position of the target object can be detected without being affected by ambient light. In addition, if a common drive signal is applied to the detection light source and the reference light source, the position of the target object can be detected without being affected by fluctuations in the intensity of the drive signal. Further, in the present invention, since the photodetector and the reference light source constitute a light receiving unit, the photodetector and the reference light source are close to each other. For this reason, it is possible to easily avoid the reference light emitted from the reference light source from leaking into the detection light emission space. Further, in the light receiving unit, the reference light emitted from the reference light source is incident on the light detector in a state where the intensity is reduced. Therefore, even if the light detector and the reference light source are close to each other, the light detector The level of detection intensity of the reference light can be kept low. Therefore, it is possible to prevent the detection intensity of the detection light at the photodetector from becoming relatively low with respect to the detection intensity of the reference light at the photodetector, so that the sensitivity when detecting the position of the target object is increased. Can be increased.

  In the present invention, in the light receiving unit, it is preferable that a light shielding portion is provided between the reference light source and the detection light emission space. According to such a configuration, it is possible to reliably avoid the reference light emitted from the reference light source from leaking into the detection light emission space.

  In the present invention, for example, in the light receiving unit, a configuration is adopted in which the photodetector is arranged at a position shifted from the emission optical axis of the reference light source. According to such a configuration, since it is the leaked light of the reference light that is incident on the photodetector, the reference light emitted from the reference light source can be incident on the photodetector with reduced intensity. it can.

  In the present invention, in the light receiving unit, a light-shielding portion having an opening for passing a part of the reference light emitted from the reference light source is provided between the photodetector and the reference light source. The configuration may be adopted. According to such a configuration, since it is a part of the reference light that is incident on the photodetector, the reference light emitted from the reference light source can be incident on the photodetector with reduced intensity. it can. In this case, the opening is a pinhole, for example.

  In the present invention, the light receiving unit employs a configuration in which a reflection surface that guides the reference light toward the photodetector is provided in the middle of the optical path from the reference light source to the photodetector. May be. According to such a configuration, even when the reference light source and the photodetector are close to each other, the reference light emitted from the reference light source is reflected by the reflecting surface and then travels to the photodetector. For this reason, the optical path from the reference light source to the photodetector can be extended, so that the reference light emitted from the reference light source can be incident on the photodetector with reduced intensity.

  In the present invention, the light receiving unit may be configured such that a filter that partially transmits the reference light is provided in the middle of the optical path from the reference light source to the photodetector. According to such a configuration, since it is a part of the reference light that is incident on the photodetector, the reference light emitted from the reference light source can be incident on the photodetector with reduced intensity. it can.

  In the present invention, when the position detection unit alternately turns on the reference light source and a plurality of detection light sources among the plurality of detection light sources by changing the combination, It is preferable to detect the position of the target object based on the result of driving the reference light source and the detection light source so that the received light intensities are equal. According to this configuration, the position of the target object can be detected without being affected by ambient light. In addition, if a common drive signal is applied to the detection light source and the reference light source, the position of the target object can be detected without being affected by fluctuations in the intensity of the drive signal.

  In the present invention, the detection light is preferably infrared light. According to such a configuration, there is an advantage that the detection light is not visually recognized.

  The optical position detection device according to the present invention can be used in a device with a position detection function. Such a device with a position detection function includes a direct-view or projection-type display device with a position detection function, a screen device with a position detection function having a screen on which information is visually recognized, a show window with a position detection function, an amusement with a position detection function Equipment etc. can be mentioned.

It is explanatory drawing which shows the principal part of the optical position detection apparatus which concerns on Embodiment 1 of this invention. It is explanatory drawing of the detection light used with the optical position detection apparatus which concerns on Embodiment 1 of this invention. It is explanatory drawing which shows a mode that the light source for a detection is lighted one after another by the predetermined pattern in the optical position detection apparatus which concerns on Embodiment 1 of this invention, and light intensity distribution is formed. In the optical position detection apparatus according to Embodiment 1 of the present invention, it is an explanatory diagram showing a state in which a light intensity distribution for coordinate detection is formed by detection light emitted from a light source for detection. It is explanatory drawing which shows typically the principle of the optical position detection apparatus which concerns on Embodiment 1 of this invention. It is explanatory drawing of the light-receiving unit used for the optical position detection apparatus which concerns on Embodiment 1 of this invention. It is explanatory drawing of the light-receiving unit used for the optical position detection apparatus which concerns on Embodiment 2 of this invention. It is explanatory drawing of the light-receiving unit used for the optical position detection apparatus which concerns on Embodiment 3 of this invention. It is explanatory drawing of the light reception unit used for the optical position detection apparatus which concerns on Embodiment 4 of this invention. It is explanatory drawing which shows typically the principal part of another optical position detection apparatus of this invention. It is explanatory drawing of two light source units which comprise a light source part in another optical position detection apparatus of this invention. It is explanatory drawing which shows the position detection principle in another optical position detection apparatus of this invention. It is explanatory drawing which shows the method of pinpointing the position of a target object in another optical position detection apparatus of this invention. It is an exploded perspective view of a display device with a position detection function (apparatus with a position detection function) to which the present invention is applied. It is explanatory drawing which shows typically the structure of the display apparatus with another position detection function (apparatus with a position detection function) of this invention.

  Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, an axis that intersects with each other will be referred to as an X axis and a Y axis, and an axis that intersects the X axis and the Y axis will be described as a Z axis. In the drawings referred to below, for convenience of explanation, the X-axis direction (first direction) is the horizontal direction, the Y-axis direction (second direction) is the vertical direction, and the Z-axis direction (third direction) is the detection light. It is represented as the direction in which the detection light travels in the exit space. In the drawings referred to below, one side in the X-axis direction is the X1 side, the other side is the X2 side, one side in the Y-axis direction is the Y1 side, and the other side is the Y2 side. In the drawings referred to in the following description, the scales of the respective members are different from each other in order to make each member large enough to be recognized on the drawings.

[Embodiment 1]
(Overall configuration of optical position detector)
FIG. 1 is an explanatory view showing a main part of an optical position detection device according to Embodiment 1 of the present invention. FIGS. 1 (a) and 1 (b) show optical components used in the optical position detection device. It is explanatory drawing which shows a layout etc., and explanatory drawing which shows the electrical structure of an optical position detection apparatus. FIG. 2 is an explanatory diagram of the detection light used in the optical position detection device according to Embodiment 1 of the present invention. FIGS. 2A, 2B, and 2C show the light reflected by the target object. Is a plan view showing how light is received by the light detector, a cross-sectional view showing how light reflected by the target object is received by the light detector, and attenuation of detected light in the light guide plate It is explanatory drawing which shows a state.

  As shown in FIGS. 1 (a), 2 (a), and 2 (b), the optical position detection device 10 of this embodiment includes a plurality of detection light sources 12 (detection light sources 12A to 12D) that emit detection light L2. ) And a light detector 30 for detecting a part of the detection light L3 reflected by the target object Ob in the detection target space 10R (the detection light L2 emission space) among the detection light L2 emitted from the detection light source 12. And.

  In the optical position detection device 10 of this embodiment, four detection light sources 12 </ b> A to 12 </ b> D are used as the plurality of detection light sources 12. Each of the plurality of detection light sources 12 is configured by an LED (light emitting diode) or the like, and emits detection light L2 made of infrared light as diverging light. That is, since the detection light L2 preferably has a wavelength region that is efficiently reflected by the target object Ob such as a finger, the detection light L2 has a peak in the infrared region where the reflectance on the surface of the human body is high. For example, the detection light L2 is near infrared light close to the visible light region, for example, light having a peak near the wavelength of 850 nm.

  Further, the optical position detection device 10 of this embodiment includes a light guide plate 13 made of a transparent resin plate such as polycarbonate or acrylic resin, and the detection light L2 emitted from the light source for detection 12 is the light guide plate 13. Is emitted to the detection target space 10R. The light guide plate 13 has a substantially rectangular planar shape, and a surface of the light guide plate 13 facing the detection target space 10R is a light emitting surface 13s. Further, the four corner portions 13 a to 13 d of the light guide plate 13 are used as light incident portions 13 e to 13 h for the detection light L <b> 2 emitted from the detection light source 12. More specifically, the four detection light sources 12 (detection light sources 12 </ b> A to 12 </ b> D) have light emitting surfaces facing the corner portions 13 a to 13 d at positions facing the corner portions 13 a to 13 d of the light guide plate 13. For this reason, the detection light L <b> 2 emitted from the detection light source 12 is incident from the corner portions 13 a to 13 d of the light guide plate 13, and then is emitted from the light emission surface 13 s while propagating through the light guide plate 13. For example, the detection light L <b> 2 a emitted from the detection light source 12 </ b> A is emitted from the light emission surface 13 s while propagating inside the light guide plate 13. Therefore, when the detection light L2 emitted from the light emission surface 13s of the light guide plate 13 to the detection target space 10R is reflected by the target object Ob positioned in the detection target space 10R, the detection light L3 reflected by the target object Ob is detected by light. Detected by the instrument 30.

  Here, a surface uneven structure, a prism structure, a scattering layer (not shown), and the like are provided on the back surface 13t or the light emitting surface 13s of the light guide plate 13, and the corner portions 13a to 13a are formed by such a light scattering structure. The light that enters from 13d and propagates inside is gradually deflected as it travels in the propagation direction, and is emitted from the light exit surface 13s. 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 in order to make the detection lights L2a to L2d uniform as necessary. For this reason, the light quantity of the detection light L2a emitted to the detection target space 10R linearly attenuates with the distance from the detection light source 12A as shown by a solid line in FIG. Further, the amount of the detection light L2b emitted to the detection target space 10R linearly attenuates with the distance from the detection light source 12B, as indicated by a dotted line in FIG. Similarly, the detection lights L2c and L2d emitted from the other detection light sources 12C and 12D are emitted from the light emission surface 13s while being attenuated. Therefore, the detection light L2 forms a light intensity distribution described later with reference to FIG. 4 in the detection target space 10R.

(Configuration of the photodetector 30)
The photodetector 30 includes a light receiving element such as a photodiode or a phototransistor, and the photodetector is directed to the detection target space 10R at a substantially central position of the side portion of the light guide plate 13 outside the detection target space 10R. . In the present embodiment, the photodetector 30 is composed of a photodiode or the like having a sensitivity region at a position substantially overlapping with the center peak of the detection light L2.

(Configuration of the light source for reference 12R)
Furthermore, the optical position detection device 10 of the present embodiment includes a reference light source 12R that causes the reference light Lr to enter the photodetector 30 without passing through the detection target space 10R, and the reference light source 12R is detected. Like the light source 12, the LED emits near infrared light close to the visible light region, for example, light having a peak near the wavelength of 850 nm as divergent light.

  In the optical position detection device 10 having such a configuration, when initial conditions of the detection light sources 12A to 12D and the photodetector 30 are set, the reference light Lr emitted from the reference light source 12R is detected by the photodetector 30. The detection intensity can be used as a reference. Further, when detecting the X coordinate, the Y coordinate, and the Z coordinate of the target object Ob by a method to be described later, the detection intensity of the reference light Lr by the photodetector 30 and the photodetector of the detection light L3 reflected by the target object Ob. The result of comparison with the detected intensity at 30 can be used.

  In the optical position detection device 10 of the present embodiment, the reference light source 12R and the light detection are performed so that the reference light Lr emitted from the reference light source 12R enters the photodetector 30 without entering the detection target space 10R. The container 30 is held inside a common unit case 15 and is configured as a light receiving unit 35. The configuration of the light receiving unit 35 will be described later with reference to FIG.

(Electrical configuration of the optical position detection device 10)
As shown in FIG. 1B, the optical position detection device 10 detects from a light source driving unit 14 that drives a detection light source 12 (detection light sources 12 </ b> A to 12 </ b> D) and a reference light source 12 </ b> R, and a photodetector 30. The light source drive unit 14 and the position detection unit 50 are configured in a common semiconductor integrated circuit 500, for example. The light source driver 14 detects the light source 12 (detection light sources 12A to 12D) and the light source drive circuit 140 (light source drive circuits 140a to 140d, 140r) for driving the reference light source 12R and the light source drive circuit 140. And a light source control unit 145 that controls lighting of the reference light source 12R (detection light sources 12A to 12D) and the reference light source 12R.

  The position detection unit 50 includes a signal processing unit 55 and a coordinate detection unit 56, and the coordinate detection unit 56 detects the position of the target object Ob based on the detection result of the photodetector 30. In this embodiment, the coordinate detection unit 56 includes an X coordinate detection unit 51, a Y coordinate detection unit 52, and a Z coordinate detection unit 53. The light source control unit 145 and the position detection unit 50 are connected by a signal line, and the driving of the detection light source 12 and the detection operation of the position detection unit 50 are performed in conjunction with each other.

(Explanation of light intensity distribution)
FIG. 3 shows a state in which the light intensity distribution is formed by sequentially lighting the detection light sources 12 (detection light sources 12A to 12D) in a predetermined pattern in the optical position detection device 10 according to the first embodiment of the present invention. It is explanatory drawing. FIG. 4 is an explanatory diagram showing a state in which a light intensity distribution for coordinate detection is formed by the detection light L2 emitted from the detection light source 12 in the optical position detection device 10 according to Embodiment 1 of the present invention. is there. In FIG. 3, the detection light source 12 that is lit is shown in gray.

  In FIG. 1A, in the optical position detection device 10 of the present embodiment, when the detection light source 12A is turned on while the other detection light sources 12B to 12D are turned off, the detection target space 10R has X A light intensity distribution is formed around the corner of the one side X1 in the axial direction and the one side Y1 in the Y-axis direction. When the detection light source 12B is turned on while the other detection light sources 12A, 12C, and 12D are turned off, the detection target space 10R has corners on the other side X2 in the X-axis direction and the other side Y2 in the Y-axis direction. A light intensity distribution centering on the portion is formed. When the detection light source 12C is turned on while the other detection light sources 12A, 12B, and 12D are turned off, the detection target space 10R has an angle on the other side X2 in the X-axis direction and one side Y1 in the Y-axis direction. A light intensity distribution centering on the portion is formed. When the detection light source 12D is turned on and the other detection light sources 12A to 12C are turned off, the detection target space 10R has corners on one side X1 in the X-axis direction and the other side Y2 in the Y-axis direction. A central light intensity distribution is formed.

  Accordingly, as shown in FIG. 3A, when the detection light sources 12A and 12D are in the on state and the other detection light sources 12B and 12C are in the off state, as shown in FIG. A first light intensity distribution L2Xa for X coordinate detection (first light intensity distribution for first coordinate detection) in which the intensity of detection light monotonously decreases from one side X1 in the axial direction toward the other side X2 is formed. In this embodiment, in the first light intensity distribution L2Xa for X coordinate detection, the intensity of the detection light L2 linearly decreases from one side X1 in the X-axis direction to the other side X2, and detection is performed in the Y-axis direction. The intensity of the light L2 is constant.

  On the other hand, as shown in FIG. 3B, when the detection light sources 12B and 12C are turned on and the other detection light sources 12A and 12D are turned off, as shown in FIG. In addition, an X coordinate detection second light intensity distribution L2Xb (first coordinate detection second light intensity distribution) in which the intensity of the detection light monotonously decreases from the other side X2 in the X-axis direction toward the one side X1 is formed. . In this embodiment, in the X-coordinate detection second light intensity distribution L2Xb, the intensity of the detection light L2 linearly decreases from the other side X2 in the X-axis direction toward the one side X1, and in the Y-axis direction, the detection is performed. The intensity of the light L2 is constant.

  Further, as shown in FIG. 3C, when the detection light sources 12A and 12C are turned on and the other detection light sources 12B and 12D are turned off, as shown in FIG. A first light intensity distribution L2Ya for Y coordinate detection (second light intensity distribution for second coordinate detection) in which the intensity of the detection light monotonously decreases from one side Y1 in the axial direction toward the other side Y2 is formed. In the present embodiment, in the first light intensity distribution L2Ya for Y-coordinate detection, the intensity of the detection light L2 decreases linearly from one side Y1 in the Y-axis direction to the other side Y2, and in the X-axis direction, detection is performed. The intensity of the light L2 is constant.

  On the other hand, as shown in FIG. 3D, when the detection light sources 12B and 12D are turned on and the other detection light sources 12A and 12C are turned off, as shown in FIG. In addition, a second light intensity distribution L2Yb for Y coordinate detection (second light intensity distribution for second coordinate detection) in which the intensity of the detected light monotonously decreases from the other side Y2 in the Y-axis direction toward the one side Y1 is formed. . In this embodiment, in the second light intensity distribution L2Yb for Y-coordinate detection, the intensity of the detection light L2 linearly decreases from the other side Y2 in the Y-axis direction toward the one side Y1, and in the X-axis direction, the detection is performed. The intensity of the light L2 is constant.

  Although illustration is omitted, when all the four detection light sources 12 (detection light sources 12A to 12D) are turned on, the intensity decreases from the light guide plate 13 toward the other side Z2 from one side Z1 in the Z-axis direction. A light intensity distribution for coordinate detection is formed. In such a Z coordinate detection light intensity distribution, the intensity monotonously decreases in the Z-axis direction, and such a change can be regarded as a substantially linear change in a limited space, ie, the detection target space 10R. In the Z coordinate detection light intensity distribution, the intensity is constant in the X-axis direction and the Y-axis direction.

(Basic principle of X coordinate detection)
In the optical position detection device 10 of this embodiment, the detection light source 12 for forming the light intensity distribution is turned on to form the light intensity distribution of the detection light L2 in the detection target space 10R, and the detection reflected by the target object Ob. The light L2 (detection light L3) is detected by the photodetector 30, and the position detection unit 50 detects the position of the target object Ob in the detection target space 10R based on the detection result of the photodetector 30. Therefore, the principle of coordinate detection will be described with reference to FIG. Note that, for example, a microprocessor unit (MPU) is used as the light source control unit 145 or the position detection unit 50 when acquiring the position information of the target object Ob in the detection target space 10R based on the detection result of the photodetector 30. Thus, it is possible to employ a configuration in which processing is performed by executing predetermined software (operation program). In addition, a configuration using hardware such as a logic circuit may be employed.

  FIGS. 5A and 5B are explanatory views schematically showing the principle of the optical position detection apparatus 10 according to Embodiment 1 of the present invention. FIGS. 5A and 5B show the detection light reflected by the target object. It is explanatory drawing which shows intensity | strength, and explanatory drawing which shows a mode that the light intensity distribution of detection light is adjusted so that the intensity | strength of the detection light reflected by the target object may become equal.

  In the optical position detection apparatus 10 of the present embodiment, the X-coordinate detection first light intensity distribution L2Xa and the X-coordinate detection second light intensity distribution L2Xb described with reference to FIGS. 4A and 4B are used. Then, the position in the X axis direction (X coordinate) is detected. At that time, the detection light sources 12A and 12D and the detection light sources 12B and 12C are driven in opposite phases. More specifically, in the first period for X coordinate detection, the light sources for detection 12A and 12D are turned on, while the light sources for detection 12B and 12C are turned off, and the first light for X coordinate detection shown in FIG. An intensity distribution L2Xa is formed. Next, the detection light sources 12A and 12D are turned off, and the detection light sources 12B and 12C are turned on to form the X coordinate detection second light intensity distribution L2Xb shown in FIG. 4B. Therefore, when the target object Ob is arranged in the detection target space 10R, the detection light L2 is reflected by the target object Ob, and a part of the reflected light is detected by the photodetector 30. Here, the first light intensity distribution L2Xa for X coordinate detection and the second light intensity distribution L2Xb for X coordinate detection have a constant distribution. Therefore, the X coordinate detection unit 51 compares the detection intensity at the photodetector 30 in the first period for X coordinate detection with the detection intensity at the photodetector 30 in the second period for X coordinate detection. The X coordinate of the target object Ob can be detected by the method described below with reference to FIG.

  First, as shown in FIG. 5A, the X-coordinate detection first light intensity distribution L2Xa and the X-coordinate detection second light intensity distribution L2Xb in the first X-coordinate detection period and the second X-coordinate detection period. It is formed so that the absolute values are equal and opposite in the X-axis direction. In this state, if the detection value LXa at the photodetector 30 in the first period for X coordinate detection is equal to the detection value LXb at the photodetector 30 in the second period for X coordinate detection, the target object Ob is X It can be seen that it is located in the axial center.

  On the other hand, when the detection value LXa at the photodetector 30 in the first period for X coordinate detection is different from the detection value LXb at the photodetector 30 in the second period for X coordinate detection, detection is performed. The control amount (drive current) for the light source for detection 12 is adjusted so that the values LXa and LXb are equal, and as shown in FIG. 5B, again for the X coordinate detection in the first period for X coordinate detection. A first light intensity distribution L2Xa is formed, and an X coordinate detection second light intensity distribution L2Xb is formed in the second X coordinate detection period. Then, the detection value LXa at the photodetector 30 in the first period for X coordinate detection is made equal to the detection value LXb at the photodetector 30 in the second period for X coordinate detection. The X coordinate of the target object Ob is determined by the ratio or difference between the control amount (current value) for the detection light sources 12A and 12D and the control amount (current value) for the detection light sources 12A and 12D when the differential is performed. Can be detected. Further, the ratio or difference between the adjustment amount ΔLXa of the control amount for the detection light source 12 in the first period for X coordinate detection and the adjustment amount ΔLXb of the control amount for the detection light source 12 in the second period for X coordinate detection. Thus, the X coordinate of the target object Ob can be detected. According to such a method, even when ambient light other than the detection light L2, for example, an infrared component included in external light is incident on the photodetector 30, the detection values LXa and LXb are equal to the detection light source 12. When the control amount is adjusted, the intensity of the infrared component included in the ambient light is canceled out, so that the infrared component included in the ambient light does not affect the detection accuracy.

(Basic principle of Y coordinate detection)
In this embodiment, the position in the Y-axis direction using the first light intensity distribution L2Ya for Y coordinate detection and the second light intensity distribution L2Yb for Y coordinate detection described with reference to FIGS. (Y coordinate) is detected. More specifically, the detection light sources 12A and 12C and the detection light sources 12B and 12D are driven in opposite phases. That is, as shown in FIG. 3C, in the first period for Y-coordinate detection, the detection light sources 12A and 12C are turned on, while the detection light sources 12B and 12D are turned off, as shown in FIG. A first light intensity distribution L2Ya for Y coordinate detection is formed. Next, in the second period for Y-coordinate detection, as shown in FIG. 3D, the detection light sources 12A and 12C are turned off, while the detection light sources 12B and 12D are turned on, as shown in FIG. A second light intensity distribution L2Yb for Y coordinate detection is formed. Accordingly, the Y-coordinate detection unit 52 compares the detection value LYa at the photodetector 30 in the first period for Y-coordinate detection with the detection value LYb at the photodetector 30 in the second period for Y-coordinate detection. The Y coordinate of the target object Ob can be detected by a method similar to the method of detecting the X coordinate.

(Basic principle of Z coordinate detection)
In the optical position detection apparatus 10 of this embodiment, in order to detect the Z coordinate, all of the detection light sources 12A to 12D are turned on to form a Z coordinate detection light intensity distribution whose intensity changes monotonously in the Z-axis direction. . Therefore, when the target object Ob is arranged in the detection target space 10R, the detection light L2 is reflected by the target object Ob, and a part of the reflected light is detected by the photodetector 30. Here, since the Z coordinate detection light intensity distribution has a constant distribution, the Z coordinate of the target object Ob can be detected based on the detection intensity of the photodetector 30.

(Coordinate detection using the reference light source 12R)
When performing the above coordinate detection, only the detection light L2 may be used. However, in the optical position detection device 10 of this embodiment, a reference light source 12R is provided. Therefore, when detecting the X coordinate and the Y coordinate of the target object Ob, the detection intensity of the reference light Lr at the photodetector 30 and the detection light reflected by the target object Ob instead of the differential between the detection light sources 12. The result of comparison with the detection intensity of the L3 photodetector 30 can be used. More specifically, the drive current for the detection light source 12 and the light detection when the reference light source 12R and some of the detection light sources 12 are differentiated so that the detection intensities at the photodetector 30 are equal. Target object using the difference or ratio of the drive current to the detection light source 12 when the reference light source 12R and the other part of the detection light source 12 are differentiated so that the detection intensities at the detector 30 are equal. The position of Ob can be detected.

  Further, when detecting the Z coordinate of the target object Ob, instead of the absolute value of the Z coordinate detection light intensity distribution, the detection intensity of the reference light Lr at the photodetector 30 and the detection light L3 reflected by the target object Ob. The result of comparison with the detection intensity at the photodetector 30 can be used. More specifically, the drive current for the detection light source 12 when the reference light source 12R and all the detection light sources 12 are differentiated so that the detection intensities at the photodetectors 30 are equal, and the detection The position of the target object Ob can be detected using the difference or ratio with respect to the drive current for the light source 12. According to such a method, when detecting the Z coordinate of the target object Ob, the infrared component included in the ambient light does not affect the detection accuracy.

  Furthermore, in this embodiment, the light source for detection 12 and the light source for reference 12R are driven by a common light source driving unit. For this reason, even if intensity fluctuations occur in the drive signals supplied to the detection light source 12 and the reference light source 12R, the position of the target object Ob can be detected without being affected by such intensity fluctuations.

(Configuration of the light receiving unit 35)
6 is an explanatory diagram of the light receiving unit 35 used in the optical position detection device 10 according to Embodiment 1 of the present invention. FIGS. 6 (a) and 6 (b) are perspective views of the light receiving unit 35, and FIG. 4 is a cross-sectional view of a light receiving unit 35. FIG.

  In FIG. 6, in the optical position detection device 10 of the present embodiment, the reference light source 12 </ b> R so that the reference light Lr emitted from the reference light source 12 </ b> R is incident on the photodetector 30 without entering the detection target space 10 </ b> R. And the photodetector 30 are held inside a common unit case 15 and are configured as a light receiving unit 35. In this embodiment, the unit case 15 is configured as a directivity adjusting member that compresses the difference between the incident light amount at the central optical axis L30 of the photodetector 30 and the incident light amount in the angular direction away from the central optical axis. ing.

  More specifically, the unit case 15 includes a black resin molded product, such as a black resin molded product or a metal processed product, and a black resin molded product sandwiching the photodetector 30 between the first light shielding member 16 and the like. The unit case 15 (the first light shielding member 16 and the second light shielding member 17) is provided with a light incident port on the center optical axis L30 side of the photodetector 30. Is made narrower than the light entrance in the angular direction away from the central optical axis L30. That is, in the unit case 15, the first light shielding member 16 and the second light shielding member 17 allow the slits 151 extending from the central optical axis L 30 side of the photodetector 30 to both sides in the circumferential direction as light entrances. The width dimension Ga of the slit 151 on the side of the central optical axis L30 is narrower than the width dimension Gb in the angular direction away from the central optical axis L30. Further, in the unit case 15, the light entrance (slit 151) is between the semi-circular portion 160 of the first light shielding member 16 and the semi-circular portion 170 of the second light shielding member 17. The portions 160 and 170 are opposed to each other in the Z-axis direction. For this reason, only the detection light L2 within the range limited in the Z-axis direction is incident on the photodetector 30. Therefore, high sensitivity can be obtained over a wide range with respect to the X coordinate and Y coordinate of the target object Ob, and only the high accuracy range can be obtained with respect to the Z coordinate.

  If the first light shielding member 16 and the second light shielding member 17 are made of metal, the unit case 15 functions as a shield member for the photodetector 30 and the like.

  In the light receiving unit 35 configured as described above, the photodetector 30 is formed in the concave portion 162 formed in the first light shielding member 16 and the second light shielding member 17 in a state of being mounted on the wiring board 31. It arrange | positions in the state standing upright in the space comprised by the recessed part 172, and has faced the light-receiving surface toward the slit 151. FIG. In the present embodiment, the portion where the wiring board 31 is disposed is a stepped portion 163 that is one step higher, and the wiring substrate 31 is disposed on the stepped portion 163. As a result, the recessed portion 162 of the first light shielding member 16 is formed with a lower portion 164 lower than the step portion 163, and the reference light source 12R extends the light emitting portion in the lateral direction (light detection) in the lower portion 164. The side where the vessel 30 is located). Here, the location where the reference light source 12R is disposed is blocked from the detection target space 10R by the upper plate portion 165 (light shielding plate portion) and the front plate portion 166 (light shielding portion). For this reason, the reference light Lr emitted from the reference light source 12R is not emitted from the slit 151. The power supply to the reference light source 12R is performed by a flexible wiring board or a linear wiring material.

  According to the light receiving unit 35 configured in this manner, the reference light source 12R is located at a position lower than the photodetector 30, and therefore the photodetector 30 is at a position shifted from the emission optical axis Lr0 of the reference light source 12R. is there. Further, the reference light Lr emitted from the reference light source 12R is divergent light. Therefore, of the reference light Lr emitted from the reference light source 12R, the light that enters the photodetector 30 is the leakage light of the reference light Lr.

(Main effects of this form)
As described above, in the optical position detection device 10 according to the present embodiment, the plurality of detection light sources 12 and the reference light source 12R are sequentially turned on to emit the detection light L2 and the reference light Lr and reflected by the target object Ob. The position of the target object Ob is detected based on the result of receiving a part of the detection light L3 by the light detector 30 and the intensity of the reference light Lr incident on the light detector 30 without passing through the detection target space 10R. For this reason, the target object Ob may be a finger or the like, and does not need to be an indicator that emits light. In addition, since the reference light Lr is used, the position of the target object Ob can be detected with high accuracy without being affected by ambient light or fluctuations in the intensity of the drive signal. Moreover, since the detection light L2 is infrared light, it is not visually recognized. Therefore, when a display device with a position detection function, which will be described later, is configured, there is an advantage that the visual recognition of information is not hindered by the detection light L2.

  Further, since the light detector 30 and the reference light source 12R constitute the light receiving unit 35, the light detector 30 and the reference light source 12R are close to each other. For this reason, it is possible to easily avoid the reference light Lr emitted from the reference light source 12R from leaking into the detection target space 10R. For example, it is ensured that the reference light Lr emitted from the reference light source 12R leaks into the detection target space 10R only by providing the front plate portion 166 (light shielding portion) between the reference light source 12R and the detection target space 10R. It can be avoided.

  Further, in the light receiving unit 35, since the reference light source 12R is located at a position lower than the light detector 30, the light detector 30 is located at a position shifted from the emission optical axis Lr0 of the reference light source 12R. Further, the reference light Lr emitted from the reference light source 12R is divergent light. For this reason, out of the reference light Lr emitted from the reference light source 12R, the light that enters the photodetector 30 is leaked light of the reference light Lr. Accordingly, since the reference light Lr emitted from the reference light source 12R is incident on the photodetector 30 in a state where the intensity is reduced, even if the photodetector 30 and the reference light source 12R are close to each other, the light detection is performed. The level of the detection intensity of the reference light Lr in the device 30 can be kept low. Therefore, the detection intensity of the detection light L2 at the photodetector 30 can be prevented from being relatively low with respect to the detection intensity of the reference light Lr at the photodetector 30, so that the position of the target object Ob is determined. Sensitivity at the time of detection can be increased.

[Embodiment 2]
FIG. 7 is a cross-sectional view of the light receiving unit 35 used in the optical position detection device 10 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.

  As shown in FIG. 7, also in the optical position detection device 10 of the present embodiment, the reference light Lr emitted from the reference light source 12R does not enter the detection target space 10R and the photodetector 30 as in the first embodiment. The reference light source 12 </ b> R and the photodetector 30 are held inside a common unit case 15 and configured as a light receiving unit 35. Further, since the reference light source 12R is located at a position lower than the photodetector 30, the photodetector 30 is at a position shifted from the emission optical axis Lr0 of the reference light source 12R. Further, the reference light Lr emitted from the reference light source 12R is divergent light. Therefore, of the reference light Lr emitted from the reference light source 12R, the light that enters the photodetector 30 is the leakage light of the reference light Lr.

  In the present embodiment, in the light receiving unit 35, a filter 18 that partially transmits the reference light Lr is provided in the middle of the optical path from the reference light source 12R toward the photodetector 30. More specifically, a filter 18 is provided in front of the reference light source 12R. For this reason, according to the present embodiment, the reference light Lr emitted from the reference light source 12R is incident on the photodetector 30 in a state where the intensity is further reduced as compared with the first embodiment. Therefore, even if the photodetector 30 and the reference light source 12R are close to each other, the level of the detection intensity of the reference light Lr at the photodetector 30 can be suppressed to a low level. Therefore, the detection intensity of the detection light L2 at the photodetector 30 can be prevented from being relatively low with respect to the detection intensity of the reference light Lr at the photodetector 30, so that the position of the target object Ob is determined. Sensitivity at the time of detection can be increased.

[Embodiment 3]
FIG. 8 is a cross-sectional view of the light receiving unit 35 used in the optical position detection apparatus 10 according to Embodiment 3 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.

  As shown in FIG. 8, in the optical position detection device 10 of the present embodiment as well, as in the first embodiment, the reference light Lr emitted from the reference light source 12R does not enter the detection target space 10R and is detected by the photodetector 30. The reference light source 12 </ b> R and the photodetector 30 are held inside a common unit case 15 and configured as a light receiving unit 35.

  More specifically, in the light receiving unit 35, the photodetector 30 is formed in the concave portion 162 formed in the first light shielding member 16 and the second light shielding member 17 in a state of being mounted on the wiring board 31. It is arranged in an upright state in the space formed by the recessed portion 172, and the light receiving surface faces the slit 151. In the present embodiment, the portion where the wiring board 31 is disposed is a stepped portion 163 that is one step higher, and the wiring substrate 31 is disposed on the stepped portion 163. As a result, the recessed portion 162 of the first light shielding member 16 is formed with a lower portion 164 lower than the step portion 163. In the lower portion 164, the reference light source 12R faces the light emitting portion upward (light detection). The direction orthogonal to the side where the vessel 30 is located). Here, the location where the reference light source 12R is disposed is shielded by the upper plate portion 165 (light shielding plate portion), and the side where the reference light source 12R is located and the side where the photodetector 30 is located. In between, the convex part 163a provided in the step part 163 is in contact with the upper plate part 165. For this reason, the convex portion 163a shields light from the side where the reference light source 12R is located and the side where the photodetector 30 is located.

  Here, the upper plate portion 165 is formed with an opening 165a that transmits a part of the reference light Lr emitted from the reference light source 12R. In this embodiment, the opening 165a is formed of a pinhole and is formed on the outgoing optical axis of the reference light source 12R.

  In the second light shielding member 17, a reflective surface 175 that reflects the reference light Lr that has passed through the opening 165 a toward the photodetector 30 is formed in a portion facing the opening 165 a. In the case where the second light shielding member 17 is made of metal, the reflecting surface 175 can be realized by making the portion facing the opening 165a a smooth surface that is inclined. Moreover, when the 2nd light shielding member 17 is resin, it can implement | achieve by sticking a reflective sheet to an inclined surface while making the part which opposes the opening part 165a into an inclined surface.

  According to the light receiving unit 35 configured as described above, only the portion of the reference light Lr emitted from the reference light source 12R that has passed through the opening 165a reaches the photodetector 30. Therefore, it is a part of the reference light Lr emitted from the reference light source 12R. Therefore, the reference light Lr emitted from the reference light source 12R can be incident on the photodetector 30 in a state where the intensity is reduced. Moreover, since the opening 165a is a pinhole, only a small portion of the reference light Lr emitted from the reference light source 12R is incident on the photodetector 30. In addition, the reference light source 12R is divergent light, and the optical path from the reference light source 12R to the photodetector 30 is long because the reflection surface 175 is provided. Therefore, the reference light Lr emitted from the reference light source 12R can be incident on the photodetector 30 in a state where the intensity is sufficiently reduced. Therefore, the detection intensity of the detection light L2 at the photodetector 30 can be prevented from being relatively low with respect to the detection intensity of the reference light Lr at the photodetector 30, so that the position of the target object Ob is determined. Sensitivity at the time of detection can be increased.

[Embodiment 4]
9 is a cross-sectional view of the light receiving unit 35 used in the optical position detection device 10 according to the fourth embodiment of the present invention. FIGS. 9A and 9B show the filter 18 and the upper plate portion 165. FIG. It is explanatory drawing at the time of arrange | positioning between 12R of reference light sources, and explanatory drawing at the time of arrange | positioning the filter 18 in the reflective surface 175. 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.

  As shown in FIG. 9, also in the optical position detection device 10 of the present embodiment, the reference light Lr emitted from the reference light source 12R does not enter the detection target space 10R and is detected as in the first and third embodiments. The reference light source 12 </ b> R and the photodetector 30 are held inside a common unit case 15 and are configured as a light receiving unit 35 so as to enter the detector 30.

  More specifically, as in the third embodiment, the wiring substrate 31 on which the photodetector 30 is mounted is disposed on the stepped portion 163, and the reference light source 12R includes the light emitting portion in the low-end portion 164. It is formed toward the upward direction (direction orthogonal to the side where the photodetector 30 is located). Here, in the upper plate portion 165 that covers the reference light source 12R, an opening 165a that transmits part of the reference light Lr emitted from the reference light source 12R is formed. In this embodiment, the opening 165a is a pinhole. In the second light shielding member 17, a reflective surface 175 that reflects the reference light Lr that has passed through the opening 165 a toward the photodetector 30 is formed in a portion facing the opening 165 a.

  Further, in the present embodiment, as in the second embodiment, a filter 18 that partially transmits the reference light Lr is provided in the middle of the optical path from the reference light source 12R toward the photodetector 30. More specifically, in the form shown in FIG. 9A, the filter 18 is disposed between the upper plate portion 165 and the reference light source 12R. Further, in the form shown in FIG. 9B, the filter 18 is disposed on the reflection surface 175. For this reason, according to the present embodiment, the reference light Lr emitted from the reference light source 12R is incident on the photodetector 30 in a state where the intensity is further reduced as compared with the second and third embodiments. Therefore, even if the photodetector 30 and the reference light source 12R are close to each other, the level of the detection intensity of the reference light Lr at the photodetector 30 can be suppressed to a low level. Therefore, the detection intensity of the detection light L2 at the photodetector 30 can be prevented from being relatively low with respect to the detection intensity of the reference light Lr at the photodetector 30, so that the position of the target object Ob is determined. Sensitivity at the time of detection can be increased.

[Another embodiment of the light receiving unit 35]
In the second and third embodiments, the opening 165a is provided on the outgoing optical axis of the reference light source 12R. However, the opening 165a (pinhole) is provided at a position shifted from the outgoing optical axis of the reference light source 12R. May be. In addition, a configuration in which a light shielding portion provided with an opening 165a or a configuration in which a reflective surface 175 is provided may be employed for the first and second embodiments. Furthermore, the configuration in which the optical path is extended by the reflecting surface 175 to attenuate the reference light Lr, or the configuration in which the light shielding unit having the opening 165a (pinhole) is provided in the reference light source 12R may be employed alone.

[Other Embodiments of Position Detection Method]
In the first to fourth embodiments of the present invention, the optical position detection device 10 including the plate-shaped light guide plate 13 has been described. However, the optical position detection of the method described in JP-T-2003-534554 The present invention may be applied to the apparatus 10 and the optical position detection apparatus 10 of the system described below.

  FIG. 10 is an explanatory view schematically showing the main part of another optical position detection apparatus 10 of the present invention. FIG. 11 is an explanatory diagram of two light source units constituting a light source unit in another optical position detection apparatus 10 of the present invention. FIG. 12 is an explanatory view showing the position detection principle in another optical position detection apparatus 10 of the present invention. FIGS. 12 (a) and 12 (b) are explanatory views of the light intensity distribution and the position where the target object exists. It is explanatory drawing of the method of acquiring information (azimuth | direction information). FIG. 13 is an explanatory diagram showing a method for specifying the position of the target object Ob in another optical position detection apparatus 10 of the present invention. Since the basic configuration of this embodiment is the same as that of Embodiment 1 and the like, common portions are denoted by the same reference numerals and description thereof is omitted.

  10 and 11, the optical position detection device 10 of the present embodiment includes a plurality of light source modules 121 and 122 that emit detection light L2 in a semicircular direction, and detection light L2 emitted from the light source modules 121 and 122. Among these, the light detector 30 that detects a part of the detection light L3 reflected by the target object Ob is included. The light source modules 121 and 122 are disposed at the same position in the Z-axis direction, and each of the light source modules 121 and 122 emits detection light L2. In this embodiment, the detection target space 10R in which the position of the target object Ob is detected is configured by the emission space of the detection light L2. Here, the light source module 121 emits the detection light L2 radially in the first period, and the light source module 122 sequentially emits the detection light L2 in the second period. Therefore, the position detection unit 50 detects the position of the target object Ob based on the light reception result of the detection light L2 at the photodetector 30 in the first period and the light reception result of the detection light L2 at the light detector 30 in the second period. Is detected.

  In adopting such a position detection method, in this embodiment, as shown in FIG. 10, the light source module 121 includes a first light source unit 12 </ b> E and a second light source unit 12 </ b> F arranged to overlap in the Y-axis direction. Similar to the light source module 121, the module 122 also includes a first light source unit 12E and a second light source unit 12F that are arranged in the Y-axis direction.

  Here, as shown in FIG. 11A, the first light source unit 12E includes a light source 120e (detection light source) formed of a light emitting element such as a light emitting diode that emits infrared light, and an arc-shaped light guide LG. The light source 120e is disposed at one end B3 of the light guide LG. The first light source unit 12E includes an arcuate irradiation direction setting unit LE including the optical sheet PS and the louver film LF along the arcuate outer peripheral surface of the light guide LG, and the arcuate shape of the light guide LG. An arc-shaped reflection sheet RS is provided along the inner peripheral surface.

  Further, as shown in FIG. 11 (b), the second light source unit 12F, like the first light source unit 12E, includes a light source 120f (detection light source) composed of a light emitting element such as a light emitting diode that emits infrared light, The light source 120f is disposed at the other end B4 of the light guide LG. Similarly to the first light source unit 12E, the second light source unit 12F includes an arc-shaped irradiation direction setting unit LE including the optical sheet PS and the louver film LF along the arc-shaped outer peripheral surface of the light guide LG. And an arcuate reflecting sheet RS is provided along the arcuate inner peripheral surface of the light guide LG.

  Note that at least one of the outer peripheral surface and the inner peripheral surface of the light guide LG is subjected to processing for adjusting the emission efficiency of the detection light from the light guide LG. A method for printing dots, a molding method for forming irregularities by a stamper or injection, or a groove processing method can be employed.

  In the optical position detection device 10 configured as described above, in the light source module 121, when the light source 120e is turned on in the first light source unit 12E, the detection light L2 is emitted to the detection target space 10R, and the first light is input to the detection target space 10R. An intensity distribution LID1 is formed. The first light intensity distribution LID1 has an angular direction corresponding to the other end B4 from an angular direction corresponding to the one end B3, as shown in FIG. It is an intensity distribution in which the intensity decreases monotonously toward the point.

  In contrast, when the light source 120f is turned on in the second light source unit 12F, the detection light is emitted to the detection target space 10R, and the second light intensity distribution LID2 is formed in the detection target space 10R. The second light intensity distribution LID2 has an angular direction corresponding to one end B3 from an angular direction corresponding to the other end B4, as shown in FIG. It is an intensity distribution in which the intensity decreases monotonously toward the point.

  Note that, in the light source module 122, when the light source 120e is turned on in the first light source unit 12E and in the light source module 122, the light source 120f is turned on in the second light source unit 12F. A distribution LID1 and a second light intensity distribution LID2 are formed. Therefore, as described below, the position of the target object Ob can be detected by using the first light intensity distribution LID1 and the second light intensity distribution LID2.

  First, when the first light intensity distribution LID1 is formed in the first light source unit 12E of the light source module 121, the irradiation direction of the detection light L2 and the intensity of the detection light L2 are indicated by a line E1 in FIG. There is a relationship. In addition, when the second light intensity distribution LID2 is formed in the second light source unit 12F of the light source module 121, the irradiation direction of the detection light L2 and the intensity of the detection light L2 are indicated by a line E2 in FIG. There is a relationship. Here, as shown in FIGS. 12B and 13, it is assumed that the target object Ob exists in the direction of the angle θ when viewed from the center PE of the light source module 121 (the center of the first light source unit 12E). In this case, when the first light intensity distribution LID1 is formed, the intensity of the detection light L2 at the position where the target object Ob is present is INTa. On the other hand, when the second light intensity distribution LID2 is formed, the intensity of the detection light L2 at the position where the target object Ob is present is INTb. Therefore, the intensity detected by the light detector 30 when the first light intensity distribution LID1 is formed is compared with the light intensity detected by the light detector 30 when the second light intensity distribution LID2 is formed. If the relationship of INTb is obtained, the angle θ (angle θ1) in the direction in which the target object Ob is located with reference to the center PE of the light source module 121 can be obtained.

  If such an operation is also performed in the light source module 122 and the angle θ (angle θ2) in the direction in which the target object Ob is located is obtained, the position of the target object Ob can be specified based on the center PE of the light source modules 121 and 122. .

  In adopting such a method, in the present embodiment, in the light source module 121, the detection intensity at the photodetector 30 when the first light intensity distribution LID1 is formed by the first light source unit 12E and the second light source unit 12F The target object Ob is determined based on the ratio of the drive currents when the drive currents when the light sources 120e and 120f are adjusted so that the detection intensities of the light detectors 30 when the two light intensity distributions LID2 are formed are equal. The angle θ (angle θ1) in the direction in which is located is obtained. Further, in the light source module 122, when the first light intensity distribution LID1 is formed by the first light source unit 12E, the detection intensity at the photodetector 30 and when the second light intensity distribution LID2 is formed by the second light source unit 12F. The angle θ (angle) in the direction in which the target object Ob is located based on the ratio of the drive currents when adjusting the drive currents when driving the light sources 120e and 120f so that the detection intensities of the light detectors 30 are equal to each other. θ2) is obtained.

  Even when the method of detecting the position of the target object Ob in this way is adopted, the driving current for the light sources 120e and 120f of the first light source unit 12E and the second light source unit 12F, the received light intensity at the photodetector 30, and It is necessary to initialize the relationship appropriately. In addition, it is preferable to avoid the influence of ambient light, fluctuations in driving current, and the like.

  Therefore, in the optical position detection device 10 of the present embodiment, as in the first to fourth embodiments, the reference light source 12R that allows the reference light Lr to enter the photodetector 30 without passing through the detection target space 10R is provided. The reference light source 12R and the photodetector 30 are held inside a common unit case 15 and are configured as a light receiving unit 35. In the light receiving unit 35 as well, if the configuration described with reference to the first to fourth embodiments is employed, the reference light from the photodetector 30 can be obtained even if the photodetector 30 and the reference light source 12R are close to each other. The level of detection intensity of Lr can be kept low. Therefore, the detection intensity of the detection light L2 at the photodetector 30 can be prevented from being relatively low with respect to the detection intensity of the reference light Lr at the photodetector 30, so that the position of the target object Ob is determined. Sensitivity at the time of detection can be increased.

[Configuration example of equipment with position detection function]
(Specific example 1 of display device with position detection function)
FIG. 14 is an exploded perspective view of a display device with a position detection function (equipment with a position detection function) including the optical position detection device 10 to which the present invention is applied. 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. In the following description, the optical position detection device 10 described with reference to FIGS. 1 to 9 is used as the optical position detection device 10. However, the optical position detection device 10 described with reference to FIGS. An expression position detection apparatus 10 may be used.

  A display device 100 with a position detection function shown in FIG. 14 includes an optical position detection device 10 and an image generation device 200. The optical position detection device 10 includes a detection light source 12 that emits detection light, and a light guide. A light plate 13 and a light detector 30 having a light detection surface directed toward the detection target space 10R are provided. The light source 12R for reference and the light detector 30 are held inside a common unit case 15, and a light receiving unit. 35. The image generation device 200 is a direct-view display device 210 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 210 includes an image display area 20R that overlaps the light guide plate 13 in plan view, and the image display area 20R overlaps the detection target space 10R in plan view.

  According to this configuration, when the image formed by the image generation device 200 is pointed with a finger (target object Ob) or the like, the pointed position can be detected by the optical position detection device 10, so the position of the finger can be determined. It can be used as input information.

(Specific example 2 of display device with position detection function)
FIG. 15 is an explanatory diagram schematically showing a configuration of another display device 100 with a position detection function (device with a position detection function) according to the present invention, and FIGS. 15A and 15B are with a position detection function. It is explanatory drawing which shows a mode that the principal part of the display apparatus 100 was seen from diagonally upward, and explanatory drawing which shows a mode seen from the horizontal direction typically. 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. In the following description, the optical position detection device 10 described with reference to FIGS. 1 to 9 is used as the optical position detection device 10. However, the optical position detection device 10 described with reference to FIGS. An expression position detection apparatus 10 may be used.

  An optical position detection apparatus 10 shown in FIG. 15 is used in a projection-type display apparatus 100 with a position detection function. The display apparatus 100 with a position detection function is an image projection apparatus called a liquid crystal projector or a digital micromirror device. 240 (image generation apparatus 200) and a screen member 290. The image projection device 240 enlarges and projects the image display light L <b> 1 from the projection lens system 260 provided on the front surface 251 of the housing 250 toward the screen member 290.

  The display device with a position detection function 100 of this embodiment includes an optical position detection device 10, and the optical position detection device 10 is on the screen surface 290 a side (in front of the screen member 290) where an image is visually recognized on the screen member 290. Is provided with a function of optically detecting the position of the target object Ob in the detection target space 10R. In this embodiment, the detection target space 10 </ b> R is a rectangular area when viewed from the normal direction with respect to the screen member 290, and overlaps with an area (image display area 20 </ b> R) onto which an image is projected by the image projection device 240 on the screen member 290. Yes.

  The optical position detection device 10 of this embodiment detects the position of the target object Ob in the XY plane (detection surface) parallel to the screen member 290 in the detection target space 10R. Therefore, in the display device 100 with a position detection function of the present embodiment, for example, the result of detecting the XY coordinates of the target object Ob in the optical position detection device 10 is used as input information for designating a part of the projected image or the like. It is possible to switch images based on the input information. Further, the optical position detection device 10 according to the present embodiment detects the position (Z coordinate) of the target object Ob in the normal direction (Z-axis direction) with respect to the screen member 290 in the detection target space 10R. Therefore, in the display device 100 with a position detection function of the present embodiment, for example, only when the target object Ob is within a predetermined distance from the screen member 290 can be handled as input information.

  In the optical position detection apparatus 10, the light guide plate 13 is provided on the back surface 290 b side of the screen member 290, and a plurality of detection light sources 12 (detection light sources 12 </ b> A to 12 </ b> D) are arranged around the light guide plate 13. ing. A light detector 30 having a light detection surface facing the detection target space 10R is disposed on the screen surface 290a side, and the reference light source 12R and the light detector 30 are disposed inside a common unit case 15. The light receiving unit 35 is held.

  In such a configuration, the detection light L2 is emitted from the back surface 290b side of the screen member 290 to the detection target space 10R. As the screen member 290, one having translucency with respect to the detection light L2 is used. More specifically, the screen member 290 is made of a fabric having a white paint applied to the screen surface 290a side or a white screen made of an embossed white vinyl material, and detects the detection light L2 made of infrared light. It has translucency. As the screen member 290, a silver screen having a high silver color to increase the reflectance of light, a pearl screen in which the fabric surface constituting the screen surface 290a side is subjected to resin processing to increase the reflectance of light, and the screen surface 290a side In this case, the screen member 290 has translucency with respect to the detection light L2 made of infrared light. ing. Note that the screen member 290 may have a black light-shielding layer formed on the back surface 290b for the purpose of improving the quality of the displayed image. In such a case, the light-shielding layer has a light-transmitting layer made of holes. A plurality of parts are formed.

  In this embodiment, the screen device for the projection display device has been described. However, a screen device with a position detection function for an electronic blackboard (equipment with a position detection function) is provided by providing the optical blackboard screen with the optical position detection device 10. ) May be configured.

10..Optical position detection device, 10R..Detection target space, 12, 12A to 12D..Light source for detection, 12R..Light source for reference, 15 .... Unit case, 16 .... First light shielding member, 17. -Second light shielding member, 18-Filter, 30-Photo detector, 35-Light receiving unit, 50-Position detector, 100-Display device with position detection function, 165-Upper plate part (light shielding plate Part), 165a ... opening, 166 ... front plate part (light-shielding part), 175 ... reflective surface, Ob ... target object

Claims (10)

An optical position detection device for optically detecting the position of a target object,
A plurality of light sources for detection that emit detection light;
A photodetector for detecting the detection light reflected by the target object located in a detection light emission space from which the detection light is emitted;
A reference light source that makes reference light incident on the photodetector without going through the detection light emission space;
The target in the detection light emission space based on the detection intensity of the detection light at the photodetector when the plurality of detection light sources are sequentially turned on, and the detection intensity of the reference light at the photodetector A position detector for detecting the position of the object;
The photodetector and the reference light source constitute a light receiving unit held in a common unit case, and the light receiving unit uses the reference light emitted from the reference light source as the reference light. An optical position detection device configured to be incident on the photodetector in a state where the intensity is lower than the intensity when directly entering the photodetector. An optical position detection device for optically detecting the position of a target object,
A plurality of light sources for detection that emit detection light;
A photodetector for detecting the detection light reflected by the target object located in a detection light emission space from which the detection light is emitted;
A reference light source that makes reference light incident on the photodetector without going through the detection light emission space;
The target in the detection light emission space based on the detection intensity of the detection light at the photodetector when the plurality of detection light sources are sequentially turned on, and the detection intensity of the reference light at the photodetector A position detector for detecting the position of the object;
The light detector and the reference light source are held in a common unit case to form a light receiving unit. In the light receiving unit, the reference light emitted from the reference light source is supplied to the light detector. A light-shielding part having an opening through which a part of the reference light emitted from the reference light source is allowed to pass is provided between the photodetector and the reference light source. An optical position detection device.   The optical position detection device according to claim 2, wherein the opening is a pinhole. An optical position detection device for optically detecting the position of a target object,
A plurality of light sources for detection that emit detection light;
A photodetector for detecting the detection light reflected by the target object located in a detection light emission space from which the detection light is emitted;
A reference light source that makes reference light incident on the photodetector without going through the detection light emission space;
The target in the detection light emission space based on the detection intensity of the detection light at the photodetector when the plurality of detection light sources are sequentially turned on, and the detection intensity of the reference light at the photodetector A position detector for detecting the position of the object;
The light detector and the reference light source are held in a common unit case to form a light receiving unit. In the light receiving unit, the reference light emitted from the reference light source is supplied to the light detector. An optical position detection device, wherein a filter that partially transmits the reference light is provided at an intermediate position in an optical path that is incident and travels from the reference light source toward the photodetector. An optical position detection device for optically detecting the position of a target object,
A plurality of light sources for detection that emit detection light;
A photodetector for detecting the detection light reflected by the target object located in a detection light emission space from which the detection light is emitted;
A reference light source that makes reference light incident on the photodetector without going through the detection light emission space;
The target in the detection light emission space based on the detection intensity of the detection light at the photodetector when the plurality of detection light sources are sequentially turned on, and the detection intensity of the reference light at the photodetector A position detector for detecting the position of the object;
The photodetector and the reference light source constitute a light receiving unit held in a common unit case, and the light receiving unit reduces the intensity of the reference light emitted from the reference light source. And enter the photodetector in the state
The position detection unit has equal received light intensity at the photodetector when the reference light source and a part of the plurality of detection light sources are alternately turned on by changing the combination. An optical position detection apparatus for detecting the position of the target object based on the result of driving the reference light source and the detection light source.   6. The optical position detection device according to claim 1, wherein in the light receiving unit, a light shielding portion is provided between the reference light source and the detection light emission space.   7. The optical position according to claim 1, wherein in the light receiving unit, the light detector is disposed at a position shifted from an emission optical axis of the reference light source. Detection device.   2. The light receiving unit according to claim 1, wherein a reflection surface that guides the reference light toward the photodetector is provided at an intermediate position of an optical path from the reference light source toward the photodetector. The optical position detection device according to any one of 1 to 7.   The optical position detection apparatus according to claim 1, wherein the detection light is infrared light.   A device with a position detection function, comprising the optical position detection device according to any one of claims 1 to 9.