JP6310684B2 - Optical position detector - Google Patents

Description

  The present invention relates to an optical position detection device that optically detects the position of a detection object.

  As described in Patent Document 1, a technique for optically detecting the position of a detection target has been proposed.

JP2013-88122A

  Now, it is desired to reduce the size of the optical position detection device.

  Therefore, the present invention has been made in view of the above-described points, and an object thereof is to provide a technique capable of downsizing an optical position detection device.

In order to solve the above-described problems, an aspect of the optical position detection device according to the present invention includes an illumination unit that irradiates light, and reflected light obtained by reflecting light emitted from the illumination unit on a detection target. A light receiving portion having a light receiving surface for receiving light, and a position acquisition portion for obtaining a position of the detection target, wherein the light receiving surface includes first to third light receiving surfaces, and the first to third light receiving surfaces. Are arranged around a reference point so as to be adjacent to the other two light receiving surfaces, and the first light receiving surface has two sides extending radially from the periphery of the reference point at a first angle. The second light receiving surface has two sides extending radially from the reference point at a second angle, and the third light receiving surface forms a third angle from the reference point. has two sides extending radially Te, the first to third angle are equal to each other, the light receiving unit, the When the morphism portion is irradiated with light, the reflected light is received by the first through third light receiving surface, the first through third light received by the light-receiving surface to the first to third electric signals, respectively The light receiving unit converts the light received by the first to third light receiving surfaces into the fourth to sixth electric signals and outputs the light when the irradiation unit is not irradiating light. The position acquisition unit defines a coordinate plane including the first to third light receiving surfaces, and subtracts the fourth to sixth electric signals from the first to third electric signals output from the light receiving unit , respectively. The first to third electric signals are corrected, and the corrected first to third electric signals are represented by first to third vectors respectively extending from the reference point to the first to third light receiving surfaces, The detection in the coordinate plane based on the first to third vectors. Determine the position of the elephant products.

  In one aspect of the optical position detection device according to the present invention, the areas of the first to third light receiving surfaces are equal to each other.

  In one aspect of the optical position detection device according to the present invention, the shapes of the first to third light receiving surfaces are congruent.

  In one aspect of the optical position detection device according to the present invention, the first to third light receiving surfaces have a fan shape.

  Moreover, in one aspect of the optical position detection device according to the present invention, the position acquisition unit is configured to be perpendicular to the coordinate plane of the detection object based on the first to third electrical signals. Find the position.

  Further, in one aspect of the optical position detection device according to the present invention, the position of the detection target obtained by the position acquisition unit is expressed within a predetermined numerical range.

  According to the present invention, the optical position detection device can be miniaturized.

It is a figure which shows schematic structure of an optical position detection apparatus. It is a figure for demonstrating operation | movement of the optical position detection apparatus which concerns on embodiment. It is a block diagram which shows the electric constitution of an optical position detection apparatus. It is a figure which shows an example of a light-receiving part. It is a figure which shows an example of the circuit diagram of an optical position detection apparatus. It is a figure which shows an example of the control content of a logic circuit. It is a figure which shows an example of a light-receiving part. It is a figure which shows an example of a light-receiving part. It is a figure which shows an example of a light-receiving part. It is a figure which shows an example of a light-receiving part. It is a figure for demonstrating the vector corresponding to an electrical signal. It is a figure for demonstrating z coordinate. It is a figure for demonstrating z coordinate. It is a figure for demonstrating the motion of reflected light. It is a figure which shows the detection result of an optical position detection apparatus. It is a figure which shows an example of a light-receiving part. It is a figure which shows an example of a light-receiving part. It is a figure which shows an example of a light-receiving part. It is a figure which shows an example of the circuit diagram of a comparison object apparatus. It is a figure which shows an example of the light-receiving part of a comparison object apparatus. It is a figure for demonstrating the motion of reflected light. It is a figure which shows the detection result of a comparison object apparatus. It is a figure which shows an example of a light-receiving part. It is a figure which shows an example of a light-receiving part. It is a figure which shows an example of a light-receiving part. It is a figure for demonstrating the vector corresponding to an electrical signal.

<< About the outline of the optical position detector >>
FIG. 1 is a diagram showing a schematic configuration of an optical position detection apparatus 1 according to the present embodiment. The optical position detection apparatus 1 according to the present embodiment optically detects the position of a detection target 60 such as a human hand or finger. As shown in FIG. 1, the optical position detection device 1 has a substantially rectangular parallelepiped shape. The optical position detection device 1 is provided with a window that transmits light, and an illumination unit 2 and a light receiving unit 3 are provided inside the window. The length of the longest side of the optical position detection device 1 is, for example, about 10 mm, but in FIG. 1, the optical position detection device 1 is shown in a size larger than the actual size for convenience. In addition, the shape of the optical position detection apparatus 1, the illumination part 2, and the light-receiving part 3 shown by FIG. 1 is an example, and is not restricted to the shape shown by FIG.

  Next, a schematic operation of the optical position detection apparatus 1 will be described with reference to FIGS. FIG. 2 is a diagram for explaining the operation of the optical position detection apparatus 1. First, the light 50 is irradiated from the illumination unit 2 (step S1 in FIG. 2), and the light 50 irradiated by the illumination unit 2 is reflected by the detection target 60 to become reflected light 51 (step S2 in FIG. 2). Then, the reflected light 51 in step S2 is received by the light receiving unit 3 (step S3 in FIG. 2). Then, the light receiving unit 3 converts the received reflected light 51 into an electric signal such as a current (photoelectric conversion) and outputs it (step S4 in FIG. 2). And the optical position detection apparatus 1 calculates | requires the position of the detection target object 60 based on the electrical signal output from the light-receiving part 3 (step S5 of FIG. 2).

  Thus, in the optical position detection apparatus 1 according to the present embodiment, the position of the detection target 60 can be detected without contact. Based on the position of the detection object 60 continuously obtained by the optical position detection device 1, for example, it is possible to detect the movement (gesture) of a human hand in a non-contact manner.

<< Electric Configuration of Optical Position Detection Device >>
FIG. 3 is a block diagram showing an electrical configuration of the optical position detection apparatus 1. As shown in FIG. 3, the optical position detection device 1 includes an illumination unit 2, a light receiving unit 3, and a control unit 10.

  The illumination unit 2 has an LED (Light Emitting Diode) 4. The LED 4 is, for example, an infrared light emitting diode that emits light in the infrared region. However, the wavelength of light emitted from the illumination unit 2 (LED 4) only needs to include a wavelength that can be photoelectrically converted by the light receiving unit 3 (that is, detectable by the light receiving unit 3). Light other than the infrared region may be used. When an infrared light emitting diode is used, the light irradiated from the illumination unit 2 (LED 4) cannot be seen by human eyes, so that the range of use of the optical position detection device 1 can be widened. In the present embodiment, the illumination unit 2 is provided integrally with the optical position detection device 1, but the illumination unit 2 may be provided separately from the optical position detection device 1.

  The light receiving unit 3 is, for example, a three-divided photodiode and includes PDs (Photodiode) 5, 6, and 7. The PDs 5 to 7 are formed by dividing a light receiving surface formed on one semiconductor substrate into three. The light receiving unit 3 may not be a divided photodiode. In this case, PD5-7 are formed on separate semiconductor substrates.

  PD 5 has a first light receiving surface 15, PD 6 has a second light receiving surface 16, and PD 7 has a third light receiving surface 17. The PD 5 receives the reflected light 51 on the first light receiving surface 15 and converts the received reflected light 51 into a first electric signal. Similarly, the PD 6 receives the reflected light 51 at the second light receiving surface 16 and converts it into a second electric signal, and the PD 7 receives the reflected light 51 at the third light receiving surface 17 and converts it into a third electric signal ( Hereinafter, the first electric signal, the second electric signal, and the third electric signal are simply referred to as “electric signals” when it is not necessary to distinguish between them. The electric signals converted by the PDs 5, 6 and 7 are output to the control unit 10.

  FIG. 4 is a diagram showing a light receiving surface of the light receiving unit 3 according to the present embodiment. As shown in FIG. 4, the first light receiving surface 15, the second light receiving surface 16, and the third light receiving surface 17 are arranged on the same plane, thereby forming one light receiving surface 14 in the entire light receiving unit 3. ing. More specifically, each of the first light receiving surface 15, the second light receiving surface 16, and the third light receiving surface 17 is arranged around the reference point 20 so as to be adjacent to the other two light receiving surfaces on the same plane. As a result, one light receiving surface 14 is formed. For example, in FIG. 4, the 1st light-receiving surface 15, the 2nd light-receiving surface 16, and the 3rd light-receiving surface 17 are arrange | positioned counterclockwise in this order.

  Further, as shown in FIG. 4, the first light receiving surface 15 has two sides 21 a and 21 b extending radially from the periphery of the reference point 20 at a first angle 24. Similarly, the second light receiving surface 16 has two sides 22 a and 22 b extending radially from the periphery of the reference point 20 at a second angle 25, and the third light receiving surface 17 corresponds to the reference point 20. It has two sides 23a and 23b extending radially from the periphery at a third angle 26. The light receiving surface 14 is formed so that the first angle 24, the second angle 25, and the third angle 26 are equal to each other. In the present embodiment, each of the first angle 24, the second angle 25, and the third angle 26 is set to 120 °. In addition, the first light receiving surface 15, the second light receiving surface 16, and the third light receiving surface 17 have a sector shape that is the same in area and shape (that is, congruent). Here, the two shapes being equal includes the case where the two shapes are similar.

  The control unit 10 controls the illumination unit 2 and the light receiving unit 3 in accordance with a control signal input from the outside, and manages the operation of the optical position detection device 1 in an integrated manner. Further, the control unit 10 obtains the position of the detection target 60 based on the first to third electrical signals output from the light receiving unit 3 and outputs a position signal.

<< About the configuration of the control unit >>
FIG. 5 is a diagram mainly illustrating an example of the configuration of the control unit 10. In the present embodiment, the control unit 10 is configured by, for example, an LSI (Large Scale Integration). As shown in FIG. 5, the control unit 10 includes amplifiers 42 a to 42 c, an arithmetic unit 43, a logic circuit 44, and an LED driver 41. Capacitors 45a to 45c are connected to the amplifiers 42a to 42c, respectively. Hereinafter, when it is not necessary to particularly distinguish the amplifiers 42a to 42c, each is referred to as an “amplifier 42”. Further, when it is not necessary to particularly distinguish the capacitors 45a to 45c, each is referred to as a “capacitor 45”.

  The LED driver 41 causes the LED 4 to emit light by applying a current to the LED 4 constituting the illumination unit 2. Thereby, light 50 is irradiated from LED4. A resistor 46 is connected to the LED driver 41. A current corresponding to the value of the resistor 46 flows through the LED 4.

  The first to third electrical signals output from the PDs 5 to 7 of the light receiving unit 3 are respectively input to the amplifiers 42a, 42b, and 42c. The amplifiers 42a to 42c amplify and output the input first to third electric signals, respectively. Specifically, each amplifier 42 subtracts the electric signal obtained by subtracting the electric signal stored in the capacitor 45 connected to the amplifier 42 from the electric signal output from the PD connected to the amplifier 42. Amplify and output. The computing unit 43 obtains the position of the detection target 60 based on the electrical signal output from each amplifier 42 when the light 50 is emitted from the LED 4.

  Here, the light received by the PD when the LED 4 emits the light 50 includes disturbance light such as sunlight (also referred to as “steady light”) in addition to the reflected light 51. Therefore, if the amplifier 42 amplifies the electric signal output from the PD as it is, the electric signal affected by the disturbance light is output from the amplifier 42. If the computing unit 43 obtains the position of the detection target 60 based on the electrical signal affected by ambient light, the accuracy of the position may be reduced.

  Therefore, in the present embodiment, an electrical signal output from the PD when the LED 4 (illumination unit 2) is not irradiating the light 50, that is, an electrical signal indicating the intensity of disturbance light is connected to the PD. Accumulated in the capacitor 45 connected to the amplifier 42. Then, the amplifier 42 uses an electric signal (electricity indicating the intensity of external light) accumulated in a capacitor 45 connected to the amplifier 42 from an electric signal output from the PD when the LED 4 is irradiating the light 50. The electric signal obtained by subtracting the signal is amplified and output to the computing unit 43. As a result, the amplifier 42 outputs an electrical signal in which the influence of disturbance light is reduced. That is, the corrected electric signal from the PD is output from the amplifier 42. Therefore, the accuracy of the position of the detection target 60 obtained by the calculator 43 is improved.

  The computing unit 43 detects the detection target in the xyz coordinate system, which will be described later, as the position of the detection target 60 based on the electrical signals output from the amplifiers 42a, 42b, and 42c when the LED 4 is irradiating the light 50. 60 x-, y-, and z-coordinates are obtained. In the present embodiment, the computing unit 43 may be referred to as a position acquisition unit. The processing performed by the computing unit 43 will be described in detail later.

  The logic circuit 44 controls the overall operation of the control unit 10 by sending an instruction signal to the LED driver 41, the amplifiers 42a, 42b, 42c, and the arithmetic unit 43. The logic circuit 44 illustrated in FIG. 5 sends instruction signals corresponding to the first input signal 48 and the second input signal 49 input from the outside to the LED driver 41, the amplifiers 42a, 42b, and 42c, and the arithmetic unit 43. To do.

  FIG. 6 is a diagram illustrating an example of control content performed by the logic circuit 44. Each of the first input signal 48 and the second input signal 49 is a binary signal, and indicates a signal level of either a high level or a low level. As illustrated in FIG. 6, the logic circuit 44 outputs an instruction signal corresponding to a combination of signal levels indicated by the first input signal 48 and the second input signal 49, the LED driver 41, the amplifiers 42 a, 42 b, 42 c and the operation. To the device 43. FIG. 6 shows four types of relationships between the input signals to the logic circuit 44 (first input signal 48 and second input signal 49) and the states of the LED driver 41, the amplifiers 42a, 42b, 42c, and the arithmetic unit 43. Has been.

  No. of FIG. 1, when both the first input signal 48 and the second input signal 49 indicate a low level, the logic circuit 44 instructs the LED driver 41 to turn off the LED 4 (illumination unit 2). An instruction signal is sent, an instruction signal for stopping the operation of the amplifiers 42a, 42b, and 42c (function OFF) is sent to the amplifiers 42a, 42b, and 42c, and an operation of the calculator 43 is paused for the calculator 43. An instruction signal to turn off the function is sent. Thereby, operation | movement of the optical position detection apparatus 1 stops.

  No. of FIG. 2, when the first input signal 48 indicates a high level and the second input signal 49 indicates a low level, the logic circuit 44 connects the LED 4 to the LED driver 41 (illumination unit 2). An instruction signal for turning off the light is sent, an instruction signal for setting the operation mode of the amplifiers 42a, 42b, and 42c to the quick charge mode is sent to the amplifiers 42a, 42b, and 42c, and the computing unit 43 is sent to the computing unit 43. An instruction signal to stop the operation is sent. When each amplifier 42 is set to the quick charge mode, the electric signal input from the PD connected to the amplifier 42 is rapidly stored in the capacitor 45 connected to the amplifier 42. As a result, an electrical signal output from the PD when the LED 4 is turned off, that is, an electrical signal indicating the intensity of disturbance light, is rapidly accumulated in the capacitor 45. No. of FIG. The instruction signal 2 is used immediately after the optical position detection device 1 is activated.

  No. of FIG. 3, when both the first input signal 48 and the second input signal 49 indicate a high level, the logic circuit 44 instructs the LED driver 41 to turn off the LED 4 (illumination unit 2). An instruction signal is transmitted, an instruction signal for setting the operation mode of the amplifiers 42a, 42b, and 42c to the normal charge mode is transmitted to the amplifiers 42a, 42b, and 42c, and the operation of the arithmetic unit 43 is suspended to the arithmetic unit 43. Sends an instruction signal to the effect. When each amplifier 42 is set to the normal charge mode, the electric signal input from the PD connected to the amplifier 42 is accumulated in the capacitor 45 connected to the amplifier 42 at a normal speed. As a result, the capacitor 45 stores an electrical signal output from the PD when the LED 4 is turned off, that is, an electrical signal indicating the intensity of disturbance light.

  No. of FIG. 4, when the first input signal 48 indicates a low level and the second input signal 49 indicates a high level, the logic circuit 44 lights the LED (illumination unit 2) to the LED driver 41. An instruction signal for setting the operation mode of the amplifiers 42a, 42b and 42c to the amplification mode, and an operation signal for performing the operation to the arithmetic unit 43. Send an instruction signal. When each amplifier 42 is set to the amplification mode, the electric signal stored in the capacitor connected to the amplifier 42 is subtracted from the electric signal input from the PD connected to the amplifier 42, thereby obtaining Amplified electrical signal is output.

  Here, the logic circuit 44 uses the first input signal 48 and the second input signal 49 to indicate No. The instruction signal shown in FIG. 4 is switched at a predetermined cycle and sent out. Therefore, the logic circuit 44 is No. The indication signal shown in FIG. 3 is sent after the instruction signal shown in FIG. Therefore, from the logic circuit 44, no. 4, each amplifier 42 determines the intensity of disturbance light accumulated in the capacitor from the electrical signal output from the PD when the LED 4 is irradiating the light 50. The electric signal shown is subtracted, and the electric signal obtained thereby is amplified and output. That is, each amplifier 42 corrects the electrical signal output from the PD when the LED 4 is irradiating the light 50 with the electrical signal indicating the intensity of the disturbance light, and amplifies the corrected electrical signal. Output. Then, the computing unit 43 obtains the position of the detection target 60 based on the electrical signal output in this way from each amplifier 42. Thereby, the calculator 43 can obtain | require the position of the detection target object 60 based on the electrical signal which shows the intensity | strength of the reflected light 51 light-received by each PD.

<< About processing of computing unit >>
7 and 9 are diagrams showing an example in which the reflected light 51 is incident on the light receiving surface 14 of the light receiving unit 3 shown in FIG. FIG. 7 shows an example when the reflected light 51 is incident on the light receiving unit center 20 perpendicularly. As shown in FIG. 7, the incident area 500 on which the reflected light 51 is incident is larger than the area of the light receiving surface 14 and the window 3b that transmits the aforementioned light. Since the light receiving unit 3 has a convex lens structure, the reflected light 51 incident on the light receiving unit 3 is collected and reaches the light receiving surface 14. The light amount distribution on the light receiving surface 14 draws a concentric circle whose center is the maximum light amount as shown in FIG. In the present embodiment, a portion of the light amount distribution on the light receiving surface 14 where the light amount is stronger than a predetermined threshold is referred to as a strong light receiving region 510. FIG. 8 is an image diagram that approximates the light amount of the strong light receiving region 510 that is incident on each of the light receiving surfaces 15, 16, and 17 shown in FIG.

  FIG. 9 shows an example when the reflected light 51 is incident from a position shifted to the upper right with respect to the light receiving unit center 20. Since the light receiving unit 3 has a convex lens structure, the light incident on the light receiving unit 3 is collected and reaches the light receiving surface 14. FIG. 10 is an image diagram that approximates a light amount of the strong light receiving region 510 that is incident on each of the light receiving surfaces 15, 16, and 17 shown in FIG.

  Since the light quantity distribution on the light receiving surface 14 depends on the shape and focal length of the lens, FIGS. 7 and 9 are examples. In addition, between the first light receiving surface 15 and the second light receiving surface 16, between the second light receiving surface 16 and the third light receiving surface 17, and between the third light receiving surface 17 and the first light receiving surface 15, actually Although a slight gap exists as shown in FIG. 4, in the following description, the first light receiving surface 15, the second light receiving surface 16, and the third light receiving surface 17 are contacted in a simplified manner as shown in FIGS. 7 to 10. Let me show you.

  As shown in FIGS. 7 to 10, the computing unit 43 (position acquisition unit 43) according to the present embodiment includes the light receiving surface 14 (the first light receiving surface 15, the second light receiving surface 16, and the third light receiving surface 17). An xy coordinate plane including the reference point 20 as an origin is defined. In the present embodiment, the x-axis of the xy coordinate plane is defined so as to pass through the boundary between the first light receiving surface 15 and the third light receiving surface 17. The computing unit 43 then defines a z-axis that is perpendicular to the x-axis and y-axis of the xy coordinate plane. The computing unit 43 detects the detection target 60 in the xyz coordinate system (orthogonal coordinate system) defined as described above as the position of the detection target 60 based on the electrical signals output from the amplifiers 42a, 42b, and 42c. X coordinate, y coordinate, and z coordinate are obtained and output. Below, the calculation method of the x coordinate, y coordinate, and z coordinate which the calculator 43 performs is demonstrated.

  Hereinafter, unless otherwise specified, simply saying “first electric signal” means the first electric signal from the corrected PD 5 output from the amplifier 42a. Further, simply speaking “second electric signal” means the second electric signal from the corrected PD 6 output from the amplifier 42b. Then, simply speaking “third electric signal” means the third electric signal from the corrected PD 7 output from the amplifier 42c.

  In the following description, the magnitude of the first electric signal (current) is A, the magnitude of the second electric signal (current) is B, and the magnitude of the third electric signal (current) is C.

<Detection of x-coordinate and y-coordinate>
Here, calculation of the x-coordinate and the y-coordinate, which is processing performed by the computing unit 43 in the present embodiment, will be described. The computing unit 43 first represents each of the first to third electric signals as a vector extending from the reference point 20 (origin) on the xy coordinate plane. A vector indicating the first electric signal is a first vector u1, a vector indicating the second electric signal is a second vector u2, and a vector indicating the third electric signal is a third vector u3. The computing unit 43 obtains the position of the detection target 60 on the xy coordinate plane (xyz coordinate system) based on the first vector u1, the second vector u2, and the third vector u3. Below, the calculation method of x coordinate and y coordinate is demonstrated in detail.

  First, the first vector u1, the second vector u2, and the third vector u3 will be described. FIG. 11 is a diagram showing the first vector u1, the second vector u2, and the third vector u3 when the reflected light 51 is received by the light receiving surface 14 as shown in FIG.

  As shown in FIG. 11, the first vector u <b> 1 extends from the reference point 20 (the origin of the xyz coordinate system) to the first light receiving surface 15. The first vector u1 extends from the reference point 20 in a direction that equally divides the first angle 24 formed by the two sides 21a and 21b of the first light receiving surface 15. The magnitude of the first vector u1 matches the magnitude of the first electric signal, that is, A.

  The second vector u2 extends from the reference point 20 to the second light receiving surface 16. The second vector u <b> 2 extends from the reference point 20 in a direction that equally divides the second angle 25 formed by the two sides 22 a and 22 b of the second light receiving surface 16. The magnitude of the second vector u2 is equal to the magnitude of the second electric signal, that is, B.

  The third vector u3 extends from the reference point 20 to the third light receiving surface 17. The third vector u3 extends from the reference point 20 in a direction that equally divides the third angle 26 formed by the two sides 23a and 23b of the third light receiving surface 17. The magnitude of the third vector u3 matches the magnitude of the third electric signal, that is, C.

  In the present embodiment, the respective directions of the first vector u1, the second vector u2, and the third vector u3 are represented by counterclockwise angles from the positive side of the x axis to the vector. Therefore, the directions of the first vector u1, the second vector u2, and the third vector u3 are 60 degrees, 180 degrees, and 300 degrees, respectively.

  The computing unit 43 determines the first vector u1, the second vector u2, and the third vector u3 in the xyz coordinate system based on the first to third electric signals, and then determines the first vector u1 and the second vector u2. Based on the third vector u3, the x coordinate and the y coordinate of the detection object 60 are obtained.

  Here, the x component x1 and the y component y1 of the combined vector of the first vector u1, the second vector u2, and the third vector u3 are expressed by the following equations (1) and (2).

  The position of the tip of the combined vector of the first vector u1, the second vector u2, and the third vector u3 indicates the position of the strong light receiving region 510 of the reflected light 51 on the light receiving surface. Since the position of the strong light receiving region 510 of the reflected light 51 on the light receiving surface 14 changes according to the position of the detection target 60, the position of the tip of the combined vector can be set as the position of the detection target 60. It is. That is, the x component x1 (the x coordinate of the position of the light receiving area of the reflected light 51 on the light receiving surface 14) of the combined vector shown in the expression (1) is set as the x coordinate of the detection target 60, and is expressed in the expression (2). The y component y1 (y coordinate of the position of the light receiving area of the reflected light 51 on the light receiving surface 14) of the combined vector can be used as the y coordinate of the detection target 60.

On the other hand, in the present embodiment, the minimum value and the maximum value of the position output voltage of the control unit 10 are 0 (V) and V _REF (V), respectively. Since the possible range of x1 and y1 represented by the expressions (1) and (2) is from −∞ to + ∞, the control unit 10 keeps x1 and y1 as they are, and the x coordinate and y coordinate of the detection target 60. Cannot be analog output.

  Therefore, in the present embodiment, equations (1) and (2) are modified to derive equations for obtaining the x-coordinate and y-coordinate of the detection target 60 that can be output to the outside by the control unit 10. Then, the x coordinate and the y coordinate of the detection target 60 are obtained using the formula.

  First, the equation (1) is transformed into the following equations (3.1) and (3.2), and x1 having the minimum and maximum values of −∞ and + ∞ is changed to the minimum and maximum values of −1. And x2 which becomes +1.

  The conditional expression B> 2 (A + C) shown in Expression (3.2) indicates that the amount of received light 51 reflected by the second light receiving surface 16 (PD6) is such that the first light receiving surface 15 and the third light receiving surface 17 ( This represents a state that is larger than twice the amount of reflected light 51 received by PD5, 7). That is, most of the reflected light 51 hits the second light receiving surface 16 (PD6), and the other first light receiving surface 15 and the third light receiving surface 17 do not receive much reflected light 51. In such a case, assuming that the position of the strong light receiving region 510 of the reflected light 51 on the light receiving surface 14 is the left end of the light receiving surface 14, x2 is set to the minimum value as shown in the equation (3.2). Fix to -1.

  Further, the equation (2) is transformed into the following equations (4.1), (4.2), (4.3), and y1 having minimum and maximum values of −∞ and + ∞ is set to the minimum value. And y2 having maximum values of -1 and +1.

  The conditional expression shown in the equation (4.2) indicates that the amount of light reflected by the first light receiving surface 15 is smaller than the amount of light received by the second light receiving surface 16 and the third light receiving surface 17. It represents an extremely large state. In such a case, assuming that the position of the strong light receiving region 510 of the reflected light 51 on the light receiving surface 14 is the upper end of the light receiving surface 14, y2 is set to the maximum value as shown in the equation (4.2). Fix to 1.

  In addition, the conditional expression shown in Expression (4.3) indicates that the amount of light reflected by the third light receiving surface 17 is equal to the amount of light reflected by the first light receiving surface 15 and the second light receiving surface 16. It represents a very large state. In such a case, the position of the strong light receiving region 510 of the reflected light 51 on the light receiving surface 14 is considered to be the lower end of the light receiving surface 14, and y2 is set to the minimum value as shown in the equation (4.3). Fix to -1.

  Next, Equations (3.1) and (3.2) are transformed into Equations (5.1) and (5.2), and x2 whose minimum and maximum values are −1 and +1 is changed to the minimum value. And x3 where the maximum value is 0 and +1.

  Further, the expressions (4.1) to (4.3) are transformed into the expressions (6.1) to (6.3), and y2 having the minimum value and the maximum value of −1 and +1 is changed to the minimum value and It is transformed into y3 where the maximum value is 0 and +1.

Next, Equations (5.1) and (5.2) are transformed into Equations (7.1) and (7.2), and x3 whose minimum and maximum values are 0 and +1 is changed to the minimum value and It is transformed to x4 where the maximum value is 0 and V _REF .

Further, the equations (6.1) to (6.3) are transformed into the equations (8.1) to (8.3), and y3 whose minimum value and maximum value are 0 and +1 is changed to the minimum value and maximum value. It is transformed to y4 where the value is 0 and V _REF .

  In the present embodiment, x4 expressed by the equations (7.1) and (7.2) is set as the x coordinate of the detection target 60. Further, y4 expressed by the equations (8.1) to (8.3) is set as the y coordinate of the detection target 60. The computing unit 43 obtains the x coordinate (x4) of the detection target 60 using the first to third electrical signals and the equations (7.1) and (7.2). The computing unit 43 obtains the y coordinate (y4) of the detection target 60 using the first to third electrical signals and the equations (8.1) to (8.3). Thereby, the control part 10 can output the x coordinate and y coordinate of the detection target object 60 calculated | required by the calculator 43 to the exterior as an analog signal.

<Detection of z coordinate>
Here, calculation of the z coordinate will be described. As described above, the z axis is an axis perpendicular to the light receiving surface 14 (xy plane). The z coordinate is obtained based on the first to third electric signals. More specifically, the z-coordinate indicates the maximum value of the first electric signal (maximum value of A) as Amax, the maximum value of the second electric signal (maximum value of B) as Bmax, and the maximum value of the third electric signal ( When the maximum value of C) is Cmax, it is expressed as shown in Equation (9). The z coordinate is in a predetermined range (that is, the minimum value is “0” and the maximum value is “V _REF ”), similarly to the x coordinate and the y coordinate. The computing unit 43 obtains the z coordinate of the detection target 60 using the first to third electrical signals and the equation (9).

  FIG. 12 is a diagram for explaining the z-coordinate obtained by the calculator 43. The z-coordinate obtained by Equation (9) takes a larger value as the position of the detection target 60 is closer to the light receiving surface 14 (light receiving unit 3), and the position of the detection target 60 is on the light receiving surface 14 (light receiving unit 3). The farther away, the smaller the value.

  Note that when only the binary value indicating whether the detection target 60 is close to or far from the light receiving surface 14 needs to be known, the computing unit 43 uses the equations (10.1) and (10.2) for the z coordinate. You may ask for it.

FIG. 13 is a diagram for explaining the z-coordinate expressed by the equations (10.1) and (10.2). As shown in equation (10.1), when (A + B + C) / (Amax + Bmax + Cmax) is larger than a predetermined threshold value β, the output of z is “V _REF ”. If the sense target 60 is approaching against the light-receiving surface 14, from becoming larger than (A + B + C) / (Amax + Bmax + Cmax) threshold beta, as shown in FIG. 13, z coordinate = V _REF is This shows that the detection target 60 is approaching the light receiving surface 14.

  On the other hand, as shown in Expression (10.2), when (A + B + C) / (Amax + Bmax + Cmax) is equal to or less than the threshold value β, the output of z is “0”. When the detection object 60 is away from the light receiving surface 14, (A + B + C) / (Amax + Bmax + Cmax) is equal to or less than the threshold value β, and therefore, the z coordinate = 0 is as shown in FIG. It shows that the detection target 60 is separated from the light receiving surface 14.

<About detection results>
Next, the detection result of the position of the detection target 60 in the optical position detection apparatus 1 will be described with reference to FIGS. FIG. 14 shows how the position of the strong light receiving region 510 of the reflected light 51 on the light receiving surface 14 changes. FIG. 15 is a diagram illustrating a detection result of the position of the detection target 60 in the optical position detection device 1 when the position of the strong light receiving region 510 of the reflected light 51 changes as illustrated in FIG. 14.

  In the example of FIG. 14, the position of the strong light receiving region 510 of the reflected light 51 changes so as to rotate once around the light receiving surface 14 counterclockwise starting from the right side of the light receiving surface 14. In the example of FIG. 14, the area of the strong light receiving region 510 of the reflected light 51 is constant. When the detection target 60 rotates in a plane parallel to the light receiving surface 14, the position of the strong light receiving region 510 of the reflected light 51 changes as shown in FIG.

  Here, the position of the strong light receiving area 510 when the position of the strong light receiving area 510 of the reflected light 51 rotates as shown in FIG. 14 is referred to as a “strong light receiving area rotation position”. Then, as shown in the upper left of FIG. 14, the strong light receiving region rotation position when the strong light receiving region 510 of the reflected light 51 exists on the right side of the light receiving surface 14 is 0 degree, and as shown in the lower left of FIG. 14. The strong light receiving region rotation position when the strong light receiving region 510 of the reflected light 51 is present on the upper side of the light receiving surface 14 is 90 degrees. Then, as shown in the lower right of FIG. 14, the strong light receiving region rotation position when the strong light receiving region 510 of the reflected light 51 exists on the left side of the light receiving surface 14 is 180 degrees, and as shown in the upper right of FIG. 14. In addition, the strong light receiving region rotation position when the strong light receiving region 510 of the reflected light 51 exists below the light receiving surface 14 is 270 degrees.

  The horizontal axis in FIG. 15 indicates the strong light receiving region rotation position. The vertical axis in FIG. 15 indicates output voltages output from the control unit 10 as the x coordinate, y coordinate, and z coordinate of the detection target 60. Graphs 71, 72, and 73 in FIG. 15 respectively show the x coordinate, the y coordinate, and the z coordinate of the detection target 60 when the strong light receiving region rotation position changes.

  As shown in the graph 71 of FIG. 15, the x-coordinate is when the reflected light rotation position is 0 degree (that is, the strong light receiving region 510 of the reflected light 51 exists on the right side of the light receiving surface 14, that is, on the positive side of the x axis. When the reflected light rotation position approaches 180 degrees (ie, the strong light receiving region 510 of the reflected light 51 is on the left side of the light receiving surface 14, that is, on the negative side in the x-axis direction). It gets smaller as you get closer. When the reflected light rotation position reaches 180 degrees, the x coordinate takes the smallest value. Thereafter, the x-coordinate increases as the reflected light rotation position approaches 360 degrees (that is, the starting position is 0 degrees). Thus, the required x coordinate changes with the change of the position of the strong light receiving region 510 of the reflected light 51 in the x-axis direction.

  Further, as shown in the graph 72 of FIG. 15, the y coordinate has a median value when the reflected light rotation position is 0 degree (when the strong light receiving region 510 of the reflected light 51 exists near the center in the y-axis direction). When the value of “0.5” is taken and the reflected light rotation position is 90 degrees (that is, when the strong light receiving region 510 of the reflected light 51 exists on the upper side of the light receiving surface 14, that is, on the positive side of the y axis), Take the largest value. After that, when the reflected light rotation position is 270 degrees (that is, when the strong light receiving region 510 of the reflected light 51 exists below the light receiving surface 14, that is, on the negative side of the y axis), the smallest value is obtained. Similarly to the x-coordinate, the y-coordinate obtained also changes as the position of the strong light receiving region 510 of the reflected light 51 in the y-axis direction changes.

  Since the distance between the light receiving surface 14 and the detection target 60 is kept constant, the z coordinate is constant as shown in the graph 73 of FIG.

  As described above, in the present embodiment, since the x coordinate, the y coordinate, and the z coordinate corresponding to the change in the actual position of the detection target 60 are obtained, the position of the detection target 60 can be accurately detected. it can.

<About the shape of the light receiving surface>
In the embodiment described above, the shape of the light receiving surface 14 is circular as shown in FIG. 4, and the shapes of the first light receiving surface 15 of PD5, the second light receiving surface 16 of PD6, and the third light receiving surface 17 of PD7 are as follows. They are fan-shaped with the same shape. However, the shape of the light receiving surface 14 and the light receiving surface of each PD may be other shapes. Even if the shape of the light receiving surface 14 and the light receiving surface of each PD is as shown in FIGS. 16, 17, and 18, for example, it can be handled in the same manner as the light receiving unit 3 (light receiving surface 14) of FIG. it can. 16, 17 and 18 are views showing the light receiving surface.

  In the example of FIG. 16, the shape of the light receiving surface 14 a of the entire light receiving unit 3 is a triangle. Further, the first light receiving surface 15a of the PD 5a, the second light receiving surface 16a of the PD 6a, and the third light receiving surface 17a of the PD 7a are triangular with the same area and shape.

  In the example of FIG. 17, the shape of the light receiving surface 14 b of the entire light receiving unit 3 is a hexagon. The first light receiving surface 15b of the PD 5b, the second light receiving surface 16b of the PD 6b, and the third light receiving surface 17b of the PD 7b are quadrangles having the same area and shape.

  In the example of FIG. 18, the shape of the light receiving surface 14 c of the entire light receiving unit 3 is a dodecagon. The first light receiving surface 15c of the PD 5c, the second light receiving surface 16c of the PD 6c, and the third light receiving surface 17c of the PD 7c are hexagons having the same area and shape.

  As shown in FIGS. 16 to 18, by making the areas and shapes of the light receiving surfaces of the plurality of PDs equal, that is, by making the shapes of the light receiving surfaces of the plurality of PDs congruent, variations in sensitivity of each PD. Can be reduced. Therefore, the detection accuracy of the position of the detection target 60 is improved.

  Further, when a divided photodiode is employed as the light receiving unit 3, variations in position and shape of the light receiving surfaces of the three PDs (PD5, 6, 7) can be reduced. Therefore, the detection accuracy of the position of the detection target 60 is improved.

<< About the optical position detection device to be compared >>
Now, an optical position detection device (hereinafter referred to as “comparison target device”) to be compared with the optical position detection device 1 of the present embodiment will be described.

<About the electrical configuration of the comparison target device>
FIG. 19 is a diagram mainly illustrating a configuration of the control unit 10 of the comparison target device. As shown in FIG. 19, the light receiving unit 3 of the comparison target device is provided with a PD 8 in addition to the PDs 5 to 7. The PD 8 converts the light received by the light receiving surface into a fourth electric signal and outputs it.

  In addition to the amplifiers 42a to 42c, the control unit 10 of the comparison target device is provided with an amplifier 43d to which the fourth electric signal from the PD 8 is input. A capacitor 45d is connected to the amplifier 43d. The operation of the amplifier 43d is similar to the operation of the amplifiers 42a to 42c described above. The first to fourth electric signals corrected by the amplifiers 42a, 42b, 42c, and 42d are input to the arithmetic unit 43.

  Hereinafter, as in the case of the first to third electric signals, unless otherwise specified, simply saying “fourth electric signal” means the fourth electric signal corrected by the amplifier 42d.

<Regarding the position detection of the x-coordinate and y-coordinate of the comparison target device>
FIG. 20 is a diagram illustrating the light receiving surface 14d of the light receiving unit 3 in the comparison target device. As shown in FIG. 20, the light receiving surface 14d includes a first light receiving surface 15d of PD5, a second light receiving surface 16d of PD6, a third light receiving surface 17d of PD7, and a fourth light receiving surface 18d of PD8. Has been. When calculating the position of the detection target 60, the computing unit 43 defines the x axis and the y axis as shown in FIG. 20, and also defines the z axis perpendicular to the x axis and the y axis. In FIG. 20, the first light receiving surface 15d, the second light receiving surface 16d, the third light receiving surface 17d, and the fourth light receiving surface 18d are shown adjacent to each other. Between the first light receiving surface 15d and the second light receiving surface 16d, between the second light receiving surface 16d and the third light receiving surface 17d, between the third light receiving surface 17d and the fourth light receiving surface 18d, and between the fourth light receiving surface 18d and the first light receiving surface. A small gap is provided between the surfaces 15d.

Here, assuming that the magnitudes of the first to fourth electric signals (currents) are A to D, the calculator 32 uses the following formulas (11) to (13) to calculate x of the detection target 60. A coordinate xc, a y coordinate yc, and a z coordinate zc are obtained. Incidentally, x-coordinate xc, y-coordinate yc and possible range of z-coordinate zc is 0 to V _REF.

<About the detection result of the comparison target device>
Next, the detection result of the position of the detection target 60 in the comparison target device will be described based on FIGS. FIG. 21 shows how the position of the strong light receiving region 510 of the reflected light 51 on the light receiving surface 14d changes. FIG. 22 is a diagram illustrating a detection result of the position of the detection target 60 in the optical position detection device 1 when the position of the strong light receiving region 510 of the reflected light 51 changes as illustrated in FIG.

  In the example of FIG. 21, as in FIG. 14 described above, the position of the strong light receiving region 510 of the reflected light 51 is rotated once around the light receiving surface 14d counterclockwise starting from the right side of the light receiving surface 14d. It has changed. In the example of FIG. 21, the area of the strong light receiving region 510 of the reflected light 51 is constant. When the detection target 60 rotates in a plane parallel to the light receiving surface 14d, the position of the strong light receiving region 510 of the reflected light 51 changes as shown in FIG.

  Graphs 71, 72, and 73 in FIG. 22 respectively show the x coordinate, the y coordinate, and the z coordinate of the detection target 60 when the strong light receiving region rotation position changes. As shown in FIG. 22, the x-coordinate, y-coordinate, and z-coordinate obtained by the comparison target device are also values according to the change in the position of the detection target 60.

<Comparison between optical position detection device and comparison target device>
As described above, when the optical position detection device 1 according to the embodiment and the comparison target device are compared, the optical position detection device 1 has one PD (light receiving surface) less than the comparison target device. Therefore, in the control unit 10 of the optical position detection device 1, the amplifier 43 and the capacitor 45 connected to the amplifier 43 can be reduced by one compared to the control unit 10 of the comparison target device. The optical position detection device 1 according to the embodiment can be made smaller than the comparison target device by deleting one PD, an amplifier, and a capacitor.

  Further, in the optical position detection device 1, special calculations are performed as shown in the equations (7.1) to (7.2), the equations (8.1) to (8.3), and the equation (9). Without using, the position of the detection object 60 can be obtained using four arithmetic operations. Therefore, it can be said that the calculation performed by the calculator 43 of the optical position detection apparatus 1 has the same degree of complexity as the calculation performed by the calculator 43 of the comparison target apparatus.

Further, when the light receiving surface 14 of the optical position detecting device 1 is circular as shown in FIG. 4 (that is, each light receiving surface of the light receiving surface 14 has a fan shape), each PD is compared with the comparison target device. The area of the light receiving surface can be increased. The area of the light receiving surface of each PD in the comparison target device illustrated in FIG. 20 is approximately a ² [mm ² ] when, for example, one side of the light receiving surface 14d is 2a [mm]. On the other hand, the area of the light receiving surface of the PD in the optical position detection apparatus 1 shown in FIG. 4, when the diameter of the light receiving surface 14 (one side) is 2a [mm] is approximately πa ^2/3 [mm ^2] and Become. That is, when the lengths of one side of the light receiving surfaces 14 and 14d are the same, the area of the light receiving surface of each PD included in the optical position detection device 1 is larger than the area of the light receiving surface of each PD included in the comparison target device. . When the area of the light receiving surface of the PD increases, the sensitivity of the PD increases. Therefore, the PD having a large area of the light receiving surface can detect the reflected light 51 having a low intensity. Therefore, the detection accuracy of the position of the detection target 60 is improved. In other words, a PD having a large light-receiving surface area can detect the reflected light 51 having a low intensity. Therefore, even if the emission intensity of the LED 4 is reduced, the position of the detection target 60 can be detected. Accuracy can be maintained. Therefore, the power consumption can be reduced while maintaining the detection accuracy of the position of the detection target 60.

Further, when the light receiving surface 14 of the optical position detecting device 1 is circular as shown in FIG. 4, the area of the light receiving surface can be made smaller than that of the comparison target device. When one side of the light receiving surfaces 14 and 14d is 2a [mm], the area of the light receiving surface 14d of the comparison target device shown in FIG. 20 is approximately 4a ² [mm ² ], whereas FIG. The area of the light receiving surface 14 in the optical position detection apparatus 1 to be obtained is approximately πa ² [mm ² ]. That is, when the lengths of one side of the light receiving surfaces 14 and 14d are the same, the area of the light receiving surface 14 of the optical position detection device 1 is smaller than the area of the light receiving surface 14d of the comparison target device. Since the area of the light receiving surface 14 is reduced, the optical position detection device 1 according to the embodiment can be arranged with electronic components and can be made smaller than the comparison target device.

<< First Modification >>
In the above-described embodiment, the case where the area and shape of the light receiving surface of each PD are equal to each other has been described as shown in FIGS. However, even if the light receiving surface 14 has a shape as shown in FIGS. 23 and 24, the position of the detection target 60 can be obtained. 23 and 24 are diagrams showing an example of the light receiving surface.

  In the light receiving surface 14f shown in FIG. 23, the shapes of the first light receiving surface 15f of the PD 5f, the second light receiving surface 16f of the PD 6f, and the third light receiving surface 17f of the PD 7f are equal to each other. However, the first light receiving surface 15f, the third light receiving surface 17f, and the second light receiving surface 16f have different areas. In the light receiving surface 14g shown in FIG. 24, the first light receiving surface 15g of the PD 5g and the third light receiving surface 17g of the PD 7g and the second light receiving surface 16g of the PD 6g have different areas and shapes.

  When the areas of the light receiving surfaces of the PDs are different, for example, even when the center position of the strong light receiving region 510 coincides with the center position (reference point 20) of the xy plane, the light is output from each PD. Since the magnitudes of the electrical signals are different from each other (more specifically, in the incident region 500 (see FIGS. 7 to 10), a PD having a large light-receiving surface can receive a large amount of reflected light 51. The magnitude of the output electrical signal will increase). When the magnitudes of the electric signals output from the PDs are different, the magnitudes of the first vector u1, the second vector u2, and the third vector u3 are also different. Therefore, even when the center position of the strong light receiving region 510 coincides with the center position of the xy plane (reference point 20), the tip of the combined vector of the first vector u1, the second vector u2, and the third vector u3. Does not indicate the center position of the strong light receiving region 510 (in this example, the position of the reference point 20). That is, when the areas of the light receiving surfaces of the PDs are different, the first to third electric signals and the expressions (7.1) to (7.2) and the expressions (8.1) to (8. 3) cannot be used to determine the x and y coordinates of the detection object 60.

  However, when the area ratio of the light receiving surface of each PD is known (in other words, when the sensitivity ratio of each PD is known), the first to third electrical signals are multiplied by a predetermined number based on the area ratio. Then, by substituting them into the equations (7.1) to (7.2) and the equations (8.1) to (8.3), for example, the first light receiving surface 15f and the third light receiving surface as shown in FIG. Even when the areas of the surface 17f and the second light receiving surface 16f are different, the x-coordinate and the y-coordinate of the detection target 60 can be obtained.

<< Second Modification >>
In the embodiment described above, the x axis of the xy coordinate plane is defined so as to pass through the boundary between the first light receiving surface 15 and the third light receiving surface 17. However, even if the xy coordinate plane is as shown in FIG. 25, the position of the detection target 60 can be obtained. FIG. 25 is a diagram illustrating a light receiving surface and an xy coordinate plane.

  In the example shown in FIG. 25, the x-axis of the xy coordinate plane is defined so that the first angle 24 on the first light receiving surface 15 is divided into 90 degrees and 30 degrees. Even when the axes of the xy coordinate plane are defined in this way, the position of the detection target 60 can be obtained in the same way as in the above-described embodiment.

  FIG. 26 is a diagram showing the first vector u1, the second vector u2, and the third vector u3 when the reflected light 51 is received by the light receiving surface 14 as shown in FIG. In FIG. 26, when the respective directions of the first vector u1, the second vector u2, and the third vector u3 are expressed by counterclockwise angles from the positive side of the x-axis to the vector, the first vector u1, the second vector u2, The directions of the vector u2 and the third vector u3 are 30 degrees, 150 degrees, and 270 degrees, respectively.

  As in the above-described embodiment, the x component of the combined vector of the first vector u1, the second vector u2, and the third vector u3 is set as the x coordinate of the detection target 60, and the y component of the combined vector is the detection target. By setting the y coordinate to 60, the position of the detection target 60 can be obtained. In other words, the position of the detection object 60 can be obtained based on the same concept as the above-described embodiment, regardless of the angle of the axis of the xy coordinate plane that is defined with respect to the light receiving surface 14.

  Although the optical position detection apparatus 1 has been described in detail above, the above description is an example for all curved surfaces, and the present invention is not limited thereto. The various examples described above can be applied in combination as long as they do not contradict each other. And it is understood that the countless modification which is not illustrated can be assumed without deviating from the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Optical position detection apparatus 2 Illumination part 3 Light-receiving part 4 LED
5, 6, 7 PD
14 light receiving surface 15 first light receiving surface 16 second light receiving surface 17 third light receiving surface 50 light 51 reflected light 60 object to be detected

Claims (7)

An illumination unit that emits light;
A light receiving unit having a light receiving surface for receiving reflected light obtained by reflecting light emitted from the illumination unit by a detection target;
A position acquisition unit for determining the position of the detection object,
The light receiving surface includes first to third light receiving surfaces,
Each of the first to third light receiving surfaces is arranged around a reference point so as to be adjacent to the other two light receiving surfaces,
The first light receiving surface has two sides extending radially at a first angle from around the reference point;
The second light receiving surface has two sides extending radially from the periphery of the reference point at a second angle;
The third light-receiving surface has two sides extending radially from the circumference of the reference point at a third angle;
The first to third angles are equal to each other;
The light receiving unit receives the reflected light from the first to third light receiving surfaces when the irradiating unit irradiates light, and each of the lights received by the first to third light receiving surfaces is first. To the third electrical signal and output it,
The light receiving unit converts the light received by the first to third light receiving surfaces when the irradiating unit is not irradiating light into fourth to sixth electric signals, respectively, and outputs the converted signals.
The position acquisition unit
Defining a coordinate plane including the first to third light receiving surfaces;
Subtracting the fourth to sixth electric signals from the first to third electric signals output from the light receiving unit to correct the first to third electric signals,
The first to third electric signals after correction are represented by first to third vectors respectively extending from the reference point to the first to third light receiving surfaces, respectively.
An optical position detection device that obtains a position of the detection object in the coordinate plane based on the first to third vectors . The optical position detection device according to claim 1,
An optical position detection device in which the areas of the first to third light receiving surfaces are equal to each other. The optical position detection device according to claim 2,
The optical position detection device, wherein the first to third light receiving surfaces have the same shape. The optical position detection device according to claim 3,
The optical position detection device, wherein the first to third light receiving surfaces have a fan shape. The optical position detection device according to any one of claims 1 to 4 ,
The position acquisition unit is an optical position detection device that determines a position of the detection target in a direction perpendicular to the coordinate plane based on the corrected first to third electric signals. An optical position detection device according to any one of claims 1 to 5 ,
The optical position detection device, wherein the position of the detection target obtained by the position acquisition unit is expressed within a predetermined numerical range. The optical position detection device according to any one of claims 1 to 6 ,
The light receiving unit is an optical position detection device including a three-division photodiode.

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