JP5423544B2 - Optical position detector - Google Patents

Description

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

As an optical position detection device for optically detecting a target object, for example, as shown in FIG. 10A, four detection light sources 12 (first detection light source 12A to fourth detection light source 12D) are used. Detection light L <b> 2 (detection light L <b> 2 a to L <b> 2 d) toward each of the target objects Ob through the translucent member 40
, And the detection light L3 reflected by the target object Ob passes through the translucent member 40 and is detected by the photodetector 30. Further, when one light detector 30 is arranged, the detection light L2
When viewed from the detection space 10R as the emission side space, as shown in FIG. 10B, a configuration in which the four detection light sources 12 are arranged at equal distances and at equal angular intervals with the photodetector 30 as the center. It has been proposed (see, for example, Patent Document 1).

In the optical position detection device having such a configuration, for example, based on the detection result of the photodetector 30, the detection light sources 12A and 12B and the detection light sources 12C and 12D are differentiated to detect the detection light sources 12A and 12A. If the 12D and the detection light sources 12B and 12C are differentiated, the X and Y coordinates of the target object Ob can be detected.

FIG. 10 of JP-T-2003-534554

However, in the configuration described in Patent Document 1, there are two pieces of information obtained by differential,
There is a problem that the detection accuracy cannot be increased. Here, the inventor proposes to obtain a large amount of information by differential and combine them to detect the position of the target object Ob. For example, based on the detection result of the photodetector 30, the first detection light source 12A and the third detection light source 12C.
And the third detection light source 1 and the distance between the first detection light source 12A and the target object Ob.
The ratio of the distance between 2C and the target object Ob is known. Further, if the second detection light source 12B and the fourth detection light source 12D are differentiated based on the detection result of the photodetector 30, the second detection light source 12 can be obtained.
The ratio of the distance between B and the target object Ob and the distance between the fourth detection light source 12D and the target object Ob are known. Accordingly, as shown in FIG. 10B, the first detection light source 12A and the third detection light source 12C.
The isoline R11 passing through the position obtained by dividing the virtual line Q11 connecting the two by the ratio and the second light source for detection 12B
If the position at which the isoline R12 passing through the position obtained by dividing the virtual line Q12 connecting the first detection light source 12D with the ratio intersects is obtained, the X coordinate and the Y coordinate of the target object Ob can be detected.

Furthermore, if the first detection light source 12A and the second detection light source 12B are differentiated, an imaginary line Q1 is obtained.
It is possible to obtain a contour line R13 passing through a position obtained by dividing 3 by a predetermined ratio.
If 2B and the third light source for detection 12C are differentiated, it is possible to obtain a contour line R14 passing through a position obtained by dividing the virtual line Q14 by a predetermined ratio. Further, if the third detection light source 12C and the fourth detection light source 12D are differentiated, an isoline R15 passing through a position obtained by dividing the virtual line Q15 by a predetermined ratio.
If the first detection light source 12A and the fourth detection light source 12D are differentiated,
The contour line R16 passing through the position obtained by dividing the virtual line Q16 by a predetermined ratio can be obtained. Therefore, since the amount of information for specifying the position of the target object Ob increases, the accuracy of position detection of the target object Ob can be increased by using a method such as averaging them.

However, if the four detection light sources 12 are arranged at equal distances and at equal angular intervals with the photodetector 30 as the center, the differential between the first detection light source 12A and the third detection light source 12C, and the second detection light source The center of differential between the light source 12B and the fourth light source for detection 12D overlaps, and the photodetector 30
The center of measurement overlaps where is located. For this reason, there exists a problem that the detection accuracy in the position away from the photodetector 30 cannot fully be raised.

When the four detection light sources 12 are arranged at equal intervals and at equal angular intervals with the photodetector 30 as the center, a virtual line Q13 connecting the first detection light source 12A and the second detection light source 12B, and the first 3
The imaginary line Q13 connecting the detection light source 12C and the fourth detection light source 12D is parallel. For this reason, the first detection light source 12A and the second detection light source 12B are differentiated, and the third detection light source 12 is obtained.
Even if C and the fourth light source for detection 12D are differentiated, only position information of the target object Ob in the same direction is obtained. Further, the virtual line Q14 connecting the second detection light source 12B and the fourth detection light source 12D and the virtual line Q16 connecting the first detection light source 12A and the fourth detection light source 12D are parallel to each other. For this reason, even if the second detection light source 12B and the fourth detection light source 12D are differentiated and the first detection light source 12A and the fourth detection light source 12D are differentiated, the target objects Ob in the same direction can be obtained. I just got location information. For this reason, even if the measurement frequency is increased, duplicated measurements are performed, so that the detection accuracy cannot be sufficiently increased.

In view of the above problems, an object of the present invention is to provide an optical position detection device capable of increasing the position detection accuracy of a target object as the measurement frequency is increased.

In order to solve the above-described problems, the present invention provides an optical position detection device including four or more light sources for detection that emit detection light for detecting the position of a target object. A light detector that receives the detection light reflected by the target object located in a side space, a light source driving unit that sequentially turns on the four or more detection light sources, and a light reception result of the light detector based on the light reception result A position detection unit that detects a position of a target object, and when viewed from the emission side space, of the four or more light sources for detection, a first detection arranged in a circumferential direction around the photodetector The light source for light, the light source for 2nd detection, the light source for 3rd detection, and the light source for 4th detection differ in the distance from the said photodetector. That is, at least one of the first light source for detection, the second light source for detection, the third light source for detection, and the fourth light source for detection is a distance from the other light source for detection and the photodetector. Are different.

In the present invention, the light source driving unit sequentially turns on four or more light sources for detection, and during that time, the photodetector receives the detection light reflected by the target object. Therefore, the position detection unit can detect the position of the target object by using the detection result of the light detector directly or by using the drive current when the two light sources for detection are differentiated via the light detector. Can do. Here, when viewed from the exit side space,
Among the four or more detection light sources, the first detection light source, the second detection light source, the third detection light source, and the fourth detection light source that are arranged in the circumferential direction around the photodetector are provided from the photodetector. The distance is different.
For this reason, since the center of the differential between the first detection light source and the third detection light source and the difference between the second detection light source and the fourth detection light source are shifted, high detection accuracy is achieved over a wide range. Can be obtained. Further, when measurement is performed using the detection light emitted from the first detection light source, the second detection light source, the third detection light source, and the fourth detection light source, measurement in overlapping directions can be avoided. it can. Therefore, the position detection accuracy of the target object can be increased by the increase in the measurement frequency.

In the present invention, when viewed from the emission side space, the first detection light source, the second detection light source, the third detection light source, and the fourth detection light source have a distance from the photodetector. All are preferably different. With this configuration, the center of the differential between the first detection light source and the third detection light source and the difference between the second detection light source and the fourth detection light source are shifted.
High detection accuracy can be obtained over a wide range. Further, even if the measurement frequency is increased, it is possible to reliably avoid performing duplicate measurements. Therefore, the position detection accuracy of the target object can be increased by the increase in the measurement frequency.

In the present invention, when viewed from the emission side space, an imaginary line connecting the first detection light source and the second detection light source, and the third detection light source and the fourth detection light source are connected. The virtual line is preferably non-parallel. With this configuration, the direction in which the position of the target object is detected using the first light source for detection and the second light source for detection, and the position of the target object using the third light source for detection and the fourth light source for detection. The direction in which is detected is different. Therefore, since it is possible to avoid performing duplicate measurements, it is possible to increase the position detection accuracy of the target object by an amount corresponding to the increase in the measurement frequency.

In the present invention, when viewed from the emission side space, a virtual line connecting the first detection light source and the fourth detection light source, the second detection light source, and the third detection light source, It is preferable that the virtual line connecting the two is non-parallel. With this configuration, the direction in which the position of the target object is detected using the first light source for detection and the fourth light source for detection, and the position of the target object using the second light source for detection and the third light source for detection. The direction in which is detected is different. Therefore, since it is possible to avoid performing duplicate measurements, it is possible to increase the position detection accuracy of the target object by an amount corresponding to the increase in the measurement frequency.

In the present invention, when viewed from the exit side space, the first detection light source, the second detection light source, the third detection light source, and the fourth detection light source are centered on the photodetector. The structure arrange | positioned at an angle space | interval can be employ | adopted.

In the present invention, when viewed from the exit side space, the first detection light source, the second detection light source, the third detection light source, and the fourth detection light source are not centered on the photodetector. You may employ | adopt the structure arrange | positioned at angular intervals, such as. That is, at least one of four angles formed by two adjacent detection light sources in the first detection light source, the second detection light source, the third detection light source, and the fourth detection light source is different from the other angles. It is characterized by being different.

In this invention, the said position detection part is based on the light reception result of the said photodetector among the said 1st light source for a detection, the said 2nd light source for a detection, the said 3rd light source for a detection, and the said 4th light source for a detection. ,
It is preferable to detect the position of the target object based on a result obtained by differentiating a part of the detection light sources and another part of the detection light sources. If such a differential is used, the influence of ambient light or the like can be automatically corrected.

In the present invention, a reference light source that emits reference light incident on the photodetector without passing through the emission-side space is provided, and the position detector is configured to perform the first detection based on a light reception result of the photodetector. Among the detection light source, the second detection light source, the third detection light source, and the fourth detection light source,
A configuration may be adopted in which the position of the target object is detected based on a plurality of results obtained by differentiating a combination of some of the detection light sources and the reference light source. If such a differential is used, the influence of ambient light or the like can be automatically corrected.

In the present invention, the position detection unit may detect the target object in the direction in which the detection light is emitted based on a light reception result of the photodetector when all of the four or more detection light sources are turned on simultaneously or sequentially. A configuration for detecting the position of the position may be adopted.

In the present invention, the detection light is preferably infrared light. According to such a configuration, since the detection light is not visually recognized, the optical position detection device can be used for various devices, for example, when it is applied to a display device, the display is not hindered.

It is explanatory drawing which shows typically the principal part of the optical position detection apparatus which concerns on Embodiment 1 of this invention. It is explanatory drawing which shows the whole structure of the optical position detection apparatus which concerns on Embodiment 1 of this invention. It is explanatory drawing which shows the basic principle of the coordinate detection used with the optical position detection apparatus which concerns on Embodiment 1 of this invention. It is explanatory drawing which shows the method of specifying X coordinate and Y coordinate of a target object from the several result calculated | required by the differential in the optical position detection apparatus which concerns on Embodiment 1 of this invention. In the optical position detection apparatus according to Embodiment 1 of the present invention, it is an explanatory diagram showing the principle of detecting the position of a target object using the difference between reference light and detection light. It is explanatory drawing which shows the processing content etc. which are performed in the position detection part in the optical position detection apparatus which concerns on Embodiment 1 of this invention. It is explanatory drawing which shows typically the principal part of the optical position detection apparatus which concerns on Embodiment 2 of this invention. It is explanatory drawing which shows the method of specifying X coordinate and Y coordinate of a target object from the several result calculated | required by the difference in the optical position detection apparatus which concerns on Embodiment 2 of this invention. It is explanatory drawing of the robot arm which provided the optical position detection apparatus which concerns on Embodiment 1 of this invention in the hand apparatus. It is explanatory drawing of the conventional optical position detection apparatus.

Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, the axes intersecting each other will be described as the X axis, the Y axis, and the Z axis, and the emission direction of the detection light will be described as the Z axis direction. 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. Further, in the following description, the corresponding components are described with the same reference numerals so that the correspondence with the configuration shown in FIG. 10 is easily understood.

[Embodiment 1]
(overall structure)
FIG. 1 is an explanatory view schematically showing a main part of an optical position detection device according to Embodiment 1 of the present invention. FIGS. 1A and 1B are components of the optical position detection device. It is explanatory drawing which shows three-dimensional arrangement | positioning, and explanatory drawing which shows the planar arrangement | positioning of the component of an optical position detection apparatus. FIG.
These are explanatory drawings which show the whole structure of the optical position detection apparatus which concerns on Embodiment 1 of this invention.

1 and 2, an optical position detection device 10 of this embodiment is an optical device used as a tactile sensor or the like in a robot hand device, and emits detection light L2 toward one side Z1 in the Z-axis direction. A light source device 11 including a plurality of detection light sources 12 and a light detector 30 that detects the detection light L3 reflected by the target object Ob. The optical position detection device 10 may have a sheet-like or plate-like translucent member 40, and in this case, the translucent member 4.
The position of the target object Ob located on the first surface 41 side of 0 is detected. Therefore, the light source for detection 12 emits the detection light L2 from the second surface 42 side opposite to the first surface 41 side in the translucent member 40 to the first surface 41 side. Detection light L3 reflected by Ob and transmitted to the second surface 42 side of the translucent member 40 is detected. For this reason, the light receiving portion 31 of the photodetector 30 faces the second surface 42 of the translucent member 40.

In this embodiment, the light source device 11 includes four or more detection light sources as the plurality of detection light sources 12, and in this embodiment, the number of the detection light sources 12 is four. More specifically,
The light source device 11 includes, as a plurality of detection light sources 12, a first detection light source 12A, a second detection light source 12B, a third detection light source 12C, and a fourth detection light source 12D. 12 has the light emitting portions 120 a to 120 d directed to the light transmissive member 40. Accordingly, the detection light L2 emitted from the detection light source 12 is transmitted through the translucent member 40 and emitted to the first surface 41 side (the emission side space of the detection light L2 from the light source device 11). The detection space 10R in which the position of the target object Ob is detected by the emission side space (the space on the first surface 41 side).
Is configured.

The first detection light source 12A, the second detection light source 12B, the third detection light source 12C, and the fourth detection light source 12D have the central optical axis of the photodetector 30 when viewed from the detection space 10R (Z-axis direction). It is arranged around in this order.

Further, the first detection light source 12A, the second detection light source 12B, the third detection light source 12C, and the fourth detection light source 12D are arranged at equiangular intervals with the photodetector 30 as the center. That is,
The central angle when the light detector 30 and the first detection light source 12A, the second detection light source 12B, the third detection light source 12C, and the fourth detection light source 12D are connected by a straight line is expressed as follows: Θ _AB = first Angle formed by detection light source 12A, photodetector 30, and second detection light source 12B Θ _BC = angle formed by second detection light source 12B, photodetector 30, and third detection light source 12C Θ _CD = for third detection Angle Θ _AD formed by light source 12C, photodetector 30, and fourth detection light source 12D is defined as angle Θ _AD = angle formed by first detection light source 12A, photodetector 30, and fourth detection light source 12D. _{AB, Θ BC, Θ CD,} Θ AD the following relationship _{Θ AB = Θ BC = Θ CD} = Θ AD = 90 °
Is set to

Here, the first detection light source 12A, the second detection light source 12B, the third detection light source 12C, and the fourth detection light source 12D are the first detection light source 1 when viewed from the detection space 10R (Z-axis direction).
The distance between 2A and the photodetector 30, the distance between the second detection light source 12B and the photodetector 30, the distance between the third detection light source 12C and the photodetector 30, and the fourth detection light source 12D and the light detection. The distance from the vessel 30 is different.

More specifically, the distance between the first detection light source 12 </ b> A and the photodetector 30, the second detection light source 12.
B, the distance between the photodetector 30, the distance between the third detection light source 12 </ b> C and the photodetector 30, and the fourth
When the distances between the detection light source 12D and the photodetector 30 are r ₁ , r ₂ , r ₃ , and r ₄ , the distances r ₁ , r ₂ , r ₃ , and r ₄ satisfy the following conditions: r ₄ < r ₁ <r ₂ <r ₃
Is set to

Further, the virtual line connecting the first detection light source 12A and the second detection light source 12B and the virtual line connecting the third detection light source 12C and the fourth detection light source 12D are non-parallel, and the first Light source for detection 1
The virtual line connecting 2A and the fourth detection light source 12D and the virtual line connecting the second detection light source 12B and the third detection light source 12C are nonparallel.

In this embodiment, each of the detection light sources 12 is composed of a light emitting element such as an LED (light emitting diode), and in this embodiment, each of the detection light sources 12 has a peak wavelength of 840 to 1.
Detection light L2 (detection light L2a to L2d) made of infrared light located at 000 nm is emitted as diverging light.

The light source device 11 also includes a reference light source 12R in which the light emitting unit 120r faces the photodetector 30. Similarly to the detection light source 12, the reference light source 12 </ b> R is configured by an LED (light emitting diode) or the like, and the reference light source 12 </ b> R uses the reference light Lr composed of infrared light having a peak wavelength of 840 to 1000 nm as diverging light. discharge. However, the reference light Lr emitted from the reference light source 12R is directed to the direction of the reference light source 12R or a light shielding cover (
For example, the light does not enter the first surface 41 side (detection space 10R) of the translucent member 40 but enters the light detector 30 without passing through the detection space 10R.

The photodetector 30 includes a photodiode, a phototransistor, or the like with the light receiving unit 31 facing the translucent member 40. In this embodiment, the photodetector 30 is a photodiode having a sensitivity peak in the infrared region.

(Configuration of position detector, etc.)
As shown in FIG. 2, the light source device 11 includes a light source driving unit 14 that drives a plurality of light sources 12 for detection. The light source driving unit 14 controls the light source driving circuit 140 that drives the detection light source 12 and the reference light source 12R, and the lighting pattern of each of the plurality of detection light sources 12 and the reference light source 12R via the light source driving circuit 140. A light source controller 145. The light source driving circuit 140 drives the first detection light source 12A to the fourth detection light source 12D.
a to 140d and a light source driving circuit 140r for driving the reference light source 12R. The light source control unit 145 controls all of the light source driving circuits 140a to 140d and 140r.

A position detector 50 is electrically connected to the photodetector 30, and the detection result of the photodetector 30 is output to the position detector 50. The position detection unit 50 includes a signal processing unit 55 for detecting the position of the target object Ob based on the detection result of the photodetector 30. The signal processing unit 55 includes an amplifier, a comparator, and the like. ing. Further, the position detection unit 50 detects the X of the target object Ob.
An X coordinate detection unit 51 that detects coordinates, and a Y coordinate detection unit 52 that detects Y coordinates of the target object Ob.
And a Z coordinate detection unit 53 for detecting the Z coordinate of the target object Ob. The position detection unit 50 and the light source driving unit 14 configured as described above operate in conjunction with each other and perform position detection described later.

(Principle of coordinate detection using differential)
FIG. 3 is an explanatory diagram showing the basic principle of coordinate detection used in the optical position detection device 10 according to Embodiment 1 of the present invention, and FIGS. 3A and 3B show the position of the target object Ob. And an explanatory diagram schematically showing the relationship between the received light intensity at the light detector 30 and the adjustment of the emission intensity of the detection light L2 so that the received light intensity at the detector 30 is equal. It is. FIG. 4 is an explanatory diagram illustrating a method for specifying the X coordinate and the Y coordinate of the target object Ob from a plurality of results obtained by differential in the optical position detection device 10 according to the first embodiment of the present invention.

In the optical position detection device 10 of the present embodiment, as described below with reference to FIGS.
The position detection unit 50 is a differential between the detection light sources 12 or the detection light source 12 and the reference light source 1.
Due to the differential with 2R, one of the two detection light sources 12 and the target object O are detected.
The ratio of the distance to b and the distance between the other detection light source 12 and the target object Ob is obtained, and the position of the target object Ob is detected based on the ratio.

In the optical position detection device 10 of the present embodiment, the first surface 41 side of the translucent member 40 (light source device 1
The detection space 10R is set in the space on the emission side of the detection light L2 from 1. Also, the two detection light sources 12, for example, the first detection light source 12A and the third detection light source 12C are separated from each other in the X-axis direction and the Y-axis direction. Therefore, the first detection light source 12A is turned on and the detection light L2a.
As shown in FIG. 3A, the detection light L2a forms a first light intensity distribution L2Ga whose intensity monotonously decreases from one side to the other side, as shown in FIG. Further, when the third detection light source 12C is turned on and the detection light L2c is emitted, the detection light L2c is transmitted through the translucent member 40 and the first surface 41.
A second light intensity distribution L2Gc in which the intensity monotonously increases from one side to the other side is formed on the side (detection space 10R).

In order to obtain the position information of the target object Ob using the differential between the detection lights L2a and L2c, as shown in FIG. 3A, first, the first detection light source 12A is turned on, 3 The light source 12C for detection is turned off, and a first light intensity distribution L2Ga in which the intensity monotonously decreases from one side to the other side is formed. Further, the first detection light source 12A is turned off while the third detection light source 12C is turned on to form a second light intensity distribution L2Gc in which the intensity monotonously increases from one side to the other side. Therefore, when the target object Ob is arranged in the detection 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. At that time, the reflection intensity at the target object Ob is proportional to the intensity of the detection light L2 at the position where the target object Ob is located, and the received light intensity at the photodetector 30 is proportional to the reflection intensity at the target object Ob. Accordingly, the received light intensity at the photodetector 30 is a value corresponding to the position of the target object Ob. Therefore, as shown in FIG. 3B, the detection value LGa when the first light intensity distribution L2Ga is formed and the photodetector 30 when the second light intensity distribution L2Gc is formed. The drive current when adjusting the control amount (drive current) for the first detection light source 12A and the control amount (drive current) for the third detection light source 12C were adjusted so that the detection value LGc at If the ratio to the driving current at the time, the ratio of the adjustment amount, or the like is used, the target object Ob in the XY plane becomes the first light source 12A
And the third detection light source 12C can be detected.

Such a model will be described mathematically. First, reflectance of below T = target object Ob each parameter A _t = detection light L2 emitted from the first detection light source 12A is reflected by the target object Ob
Distance function to the light detector 30 A = When the target object Ob exists in the detection space 10R, the first detection light source 12A
Detection intensity C _t of the light detector 30 when it is lit = Detection light L2 emitted from the third detection light source 12C is reflected by the target object Ob
Distance function to the light detector 30 C = the third detection light source 12C is in a state where the target object Ob exists in the detection space 10R.
It is set as the detection intensity of the light detector 30 when it is turned on. The light emission intensity of the first detection light source 12A and the third detection light source 12C is represented by the product of the drive current and the light emission coefficient. In the following description, the light emission coefficient is 1. In the above-described differential, the driving current for the first detection light source 12A when the received light intensity at the photodetector 30 becomes equal is I _A, and the driving current for the third detection light source 12C is I _C. .

Further, when the above-described differential is performed in a state where the target object Ob exists in the detection space 10R,
A = T × A _t × I _A + Ambient Light ・ ・ Formula (1)
C = T × C _t × I _C + Ambient Light ・ ・ Formula (2)
The relationship is obtained.

Here, since the detection intensity of the photodetector 30 at the time of the differential is equal, from the formulas (1) and (2), the following formula T × A _t × I _A + ambient light = T × C _t × I _C + Ambient light T × A _t × I _A = T × C _t × I _C .. (3)
Is guided.

Further, the ratio P _AC between the distance functions A _t and C _t is expressed by the following equation: P _AC = A _t / C _t ··· (4)
From the formulas (3) and (4), the ratio P _AC is P _AC = I _C / I _A ··· Formula (5)
It is expressed as In the equation (5), there is no term of ambient light and no term of reflectance of the target object Ob. Therefore, the ambient light and the reflectance of the target object Ob do not affect the ratio P _AC between the distance functions A _t and C _t . In addition, about said mathematical model, you may correct | amend in order to cancel the influence etc. of the detection light L2 which entered without reflecting with the target object Ob.

Here, the light source for detection 12 is a point light source, and the light intensity at a certain point is 2 of the distance from the light source.
Inversely proportional to the power. Therefore, the ratio of the separation distance P1 between the first detection light source 12A and the target object Ob and the separation distance P2 between the third detection light source 12C and the target object Ob is expressed by the following formula: P _AC = (P1) ² :( P2) ²
Is required. Therefore, the target object Ob, as shown in FIG. 4, is an isoline R1 passing through a position obtained by dividing a virtual line Q11 connecting the detection light source 12A and the third detection light source 12C by P1: P2.
1 that the target object Ob exists.

Similarly, the second detection light source 12B and the fourth detection light source 12D are differentiated, and the distance between the second detection light source 12B and the target object Ob, and the fourth detection light source 12D and the target object Ob. If the distance ratio is obtained, the target object Ob may exist on the contour line R12 passing through the position obtained by dividing the virtual line Q12 connecting the second detection light source 12B and the fourth detection light source 12D by the distance ratio. Recognize.

Further, if the first detection light source 12A and the second detection light source 12B are differentiated, a position obtained by dividing the virtual line Q13 connecting the first detection light source 12A and the second detection light source 12B by a predetermined ratio. A contour line R13 passing through can be obtained. The second detection light source 12B and the third detection light source 1
If 2C is differentiated, a virtual line Q connecting the second detection light source 12B and the third detection light source 12C.
It is possible to obtain a contour line R14 passing through a position obtained by dividing 14 by a predetermined ratio. If the third detection light source 12C and the fourth detection light source 12D are differentiated, the third detection light source 12C and the fourth detection light source 12C
It is possible to obtain the contour line R15 passing through the position obtained by dividing the virtual line Q15 connecting the detection light source 12D by a predetermined ratio. Further, if the first detection light source 12A and the fourth detection light source 12D are differentiated, the virtual line Q16 connecting the first detection light source 12A and the fourth detection light source 12D is divided by a predetermined ratio. A contour line R16 passing through can be obtained. FIG. 4 shows the principle adopted in this embodiment geometrically, and actually, the calculation is performed using the obtained data.

According to such a configuration, since there is a large amount of information for specifying the position of the target object Ob, the position detection accuracy of the target object Ob can be improved by using a method such as averaging all of a plurality of results obtained by differential. Can be increased.

(Differential between reference light Lr and detection light L2)
FIG. 5 is an explanatory diagram showing the principle of detecting the position of the target object Ob using the difference between the reference light Lr and the detection light L2 in the optical position detection device 10 according to the first embodiment of the present invention. Yes,
5A and 5B are explanatory diagrams showing the relationship between the distance from the light source for detection 12 to the target object Ob and the received light intensity of the detection light L2, and the state after adjusting the drive current to the light source. It is explanatory drawing which shows.

In the optical position detection device 10 of the present embodiment, instead of direct differential between the detection light L2a and the detection light L2c, the differential between the detection light L2a and the reference light Lr, the detection light L2c, and the reference light Lr. Finally, a result similar to the principle described with reference to FIGS. 3A and 3B is derived. Here, the differential between the detection light L2a and the reference light Lr and the differential between the detection light L2c and the reference light Lr are performed as follows.

As shown in FIG. 5A, in the state where the target object Ob exists in the detection space 10R,
The distance from the first detection light source 12A to the object Ob, the light reception intensity D _a of the detection light L2a from the light detector 30 is monotonously changed as shown by the solid line SA. In contrast, the reference light source 12
The detection intensity of the reference light Lr emitted from R at the photodetector 30 is constant regardless of the position of the target object Ob, as indicated by the solid line SR. Thus, the received light intensity D _a of the detection light L2a from the light detector 30, the detection intensity D _r of the reference light Lr of the light detector 30 is different.

Next, as shown in FIG. 5B, at least one of the drive current for the first detection light source 12A and the drive current for the reference light source 12R is adjusted, and the detection light L2a from the photodetector 30 is adjusted. The received light intensity D _a is matched with the detected intensity D _r of the reference light Lr at the photodetector 30.
Such differential is performed between the reference light Lr and the detection light L2a, and the reference light Lr.
And the detection light L2c. Therefore, the detection lights L2a and L2c in the photodetector 30
A drive current for the first detection light source 12A when the detection result of the detection light L3a and L3c reflected by the target object Ob is equal to the detection result of the reference light Lr by the photodetector 30;
The ratio with the drive current for the third detection light source 12C can be obtained. Therefore, it is possible to detect at which position between the first detection light source 12A and the third detection light source 12C the target object Ob exists.

The above detection principle can be mathematically explained using an optical path function as follows. First, reflectance of below T = target object Ob each parameter A _t = detection light L2 emitted from the first detection light source 12A is reflected by the target object Ob
Distance function to the light detector 30 A = When the target object Ob exists in the detection space 10R, the first detection light source 12A
Detection intensity C _t of the light detector 30 when it is lit = Detection light L2 emitted from the third detection light source 12C is reflected by the target object Ob
Distance function to the light detector 30 C = the third detection light source 12C is in a state where the target object Ob exists in the detection space 10R.
Detection intensity R _{s of the} light detector 30 when it is turned on R = optical path coefficient from the reference light source 12R to the light detector 30 R = detection intensity of the light detector 30 when only the reference light source 12R is turned on. Note that the light emission intensities of the first detection light source 12A, the third detection light source 12C, and the reference light source 12R are represented by the product of the drive current and the light emission coefficient. In the following description, the light emission coefficient is 1. . Further, in the above differential, the first when the light receiving intensity at the photodetector 30 becomes equal.
The drive current for the detection light source 12A is I _A , the drive current for the third detection light source 12C is I _C, and the drive current for the reference light source 12R is I _R. Further, regarding the detection intensity of the photodetector 30 when only the reference light source 12R is lit during the differential operation, the first detection light source 12 is used.
It is assumed that the differential with A and the differential with the third detection light source 12C are the same.

When the above-described differential is performed in a state where the target object Ob exists in the detection space 10R,
A = T × A _t × I _A + Ambient Light ・ ・ Formula (6)
C = T × C _t × I _C + Ambient Light ・ ・ Formula (7)
R = R _s × I _R + Ambient Light ・ ・ Formula (8)
The relationship is obtained.

Here, since the detection intensity of the photodetector 30 at the time of differential is equal, from the formulas (6) and (8), the following formula T × A _t × I _A + ambient light = R _s × I _R + ambient light T × A _t × I _A = R _s × I _R
T × A _t = R _s × I _R / I _A ... (9)
From the formulas (7) and (8), the following formula T × C _t × I _C + environment light = R _s × I _R + environment light T × C _t × I _C = R _s × I _R
T × C _t = R _s × I _R / I _C ... (10)
Is guided.

The distance function A _t, the ratio P _AC of C _t is the formula _{P AC = A t / C t} ·· formula (11)
From the equations (9) and (10), the ratio P _AC is P _AC = I _C / I _A ··· Equation (12)
It is expressed as In the formula (12), there is no term of ambient light and no term of reflectance of the target object Ob. Therefore, the ambient light and the reflectance of the target object Ob do not affect the ratio P _AC between the distance functions A _t and C _t . In addition, about said mathematical model, you may correct | amend in order to cancel the influence etc. of the detection light L2 which entered without reflecting with the target object Ob. Further, regarding the drive current I _R for the reference light source 12R, the differential with the first detection light source 12A and the third detection light source 12 are used.
Even if the differential value is different from C, the ratio P _AC can be obtained by a substantially similar method.

Here, the light source for detection 12 is a point light source, and the light intensity at a certain point is 2 of the distance from the light source.
Inversely proportional to the power. Therefore, the ratio of the separation distance P1 between the first detection light source 12A and the target object Ob and the separation distance P2 between the third detection light source 12C and the target object Ob is expressed by the following equation: P _AC = (P1) ² :( P2) ²
Is required. Therefore, the target object Ob, as shown in FIG. 4, is an isoline R1 passing through a position obtained by dividing a virtual line Q11 connecting the detection light source 12A and the third detection light source 12C by P1: P2.
1 that the target object Ob exists.

Therefore, in this embodiment, the differential between the first detection light source 12A and the reference light source 12R, the differential between the second detection light source 12B and the reference light source 12R, and the third detection light source 12C and the reference light source 12R And the differential between the fourth detection light source 12D and the reference light source 12R are sequentially performed to obtain the ratio of the distance functions. Therefore, the separation distance between the first detection light source 12A and the target object Ob, the second detection light source 1
2B and the distance between the target object Ob, the distance between the third detection light source 12C and the target object Ob,
Further, the ratio of the separation distance between the fourth detection light source 12D and the target object Ob is known. Therefore, the X coordinate and the Y coordinate of the target object Ob can be detected by a method similar to the method described with reference to FIG. FIG. 4 shows the principle adopted in this embodiment geometrically, and actually, the calculation is performed using the obtained data.

According to such a configuration, since there is a large amount of information for specifying the position of the target object Ob, the position detection accuracy of the target object Ob can be improved by using a method such as averaging all of a plurality of results obtained by differential. Can be increased.

(Configuration Example of Position Detection Unit 50 for Differential)
FIG. 6 shows a position detector 5 in the optical position detector 10 according to Embodiment 1 of the present invention.
It is explanatory drawing which shows the processing content etc. which are performed by 0.

In carrying out the above-described differential operation, it is possible to employ a configuration in which a microprocessor unit (MPU) is used as the position detection unit 50 and processing is performed by executing predetermined software (operation program). Further, as will be described below with reference to FIG. 6, a configuration in which processing is performed by a signal processing unit using hardware such as a logic circuit may be employed. 6 shows the differential described with reference to FIG. 5. However, if the reference light source 12R is replaced with the second detection light source 12B, the differential can be applied to the differential described with reference to FIG. can do.

As shown in FIG. 6A, in the optical position detection device 10 of the present embodiment, the light source driving circuit 1
40 applies a driving pulse having a predetermined current value to the first detection light source 12A via the variable resistor 111, while applying a driving pulse having a predetermined current value to the reference light source 12R via the variable resistor 112 and the inverting circuit 113. To do. For this reason, drive pulses having opposite phases are applied to the first detection light source 12A and the reference light source 12R, so the first detection light source 12A and the reference light source 12R are alternately lit. And, when the first detection light source 12A is turned on, of the detection light L2a,
The light reflected by the target object Ob is received by the photodetector 30, and when the reference light source 12R is turned on,
The reference light Lr is received by the photodetector 30. In the light intensity signal generation circuit 150, a resistor 30r of about 1 kΩ is electrically connected in series to the photodetector 30, and a bias voltage Vb is applied to both ends thereof.

In the light intensity signal generation circuit 150, the connection point Q1 between the photodetector 30 and the resistor 30r.
The position detector 50 is electrically connected. The detection signal Vc output from the connection point Q1 between the photodetector 30 and the resistor 30r is expressed by the following equation: Vc = V30 / (V30 + resistance value of the resistor 30r)
V30: Expressed by an equivalent resistance of the photodetector 30. Therefore, when the ambient light Lc is not incident on the photodetector 30 and the ambient light Lc is incident on the photodetector 30, the ambient light Lc is incident on the photodetector 30. Increases the level and amplitude of the detection signal Vc.

The position detection unit 50 generally includes a position detection signal extraction circuit 190 and a position detection signal separation circuit 17.
0, and a light emission intensity compensation command circuit 180 are provided. The position detection signal extraction circuit 190 includes a filter 192 made of a capacitor of about 1 nF.
Reference numeral 92 functions as a high-pass filter that removes a DC component from the signal output from the connection point Q1 between the photodetector 30 and the resistor 30r. Therefore, from the detection signal Vc output from the connection point Q1 between the photodetector 30 and the resistor 30r by the filter 192, the photodetector 30 is detected.
Only the position detection signal Vd is extracted. That is, since the detection light L2a and the reference light Lr are modulated, the ambient light Lc can be considered to have a constant intensity within a certain period, and therefore, the low frequency component or direct current caused by the ambient light Lc. Ingredient is filter 19
2 to remove.

The position detection signal extraction circuit 190 has an adder circuit 193 provided with a feedback resistor 194 of about 220 kΩ at the subsequent stage of the filter 192. The position detection signal Vd extracted by the filter 192 is a bias voltage Vb. Is output to the position detection signal separation circuit 170 as a position detection signal Vs superimposed on a voltage V / 2 that is ½ of.

The position detection signal separation circuit 170 is electrically connected to the input lines of the switch 171, the comparator 172, and the comparator 172 that perform a switching operation in synchronization with the drive pulse applied to the first detection light source 12 </ b> A. The capacitor 173 is provided. Therefore, when the position detection signal Vs is input to the position detection signal separation circuit 170, the position detection signal separation circuit 170.
To the emission intensity compensation command circuit 180, the effective value Vea of the position detection signal Vs when the first detection light source 12A is turned on, and the effective value V of the position detection signal Vs when the reference light source 12R is turned on.
eb and are output alternately.

The light emission intensity compensation command circuit 180 compares the effective values Vea and Veb and performs the process shown in FIG. 6B, so that the effective value Vea of the position detection signal Vs and the effective value Veb of the position detection signal Vs are at the same level. The control signal Vf is output to the light source driving circuit 140 so that That is, the light emission intensity compensation command circuit 180 compares the effective value Vea of the position detection signal Vs with the effective value Veb of the position detection signal Vs, and maintains the current driving conditions when they are equal. On the other hand, when the effective value Vea of the position detection signal Vs is lower than the effective value Veb of the position detection signal Vs,
The light emission intensity compensation command circuit 180 lowers the resistance value of the variable resistor 111 so as to reduce the first detection light source 1.
The amount of light emitted from 2A is increased. Further, the effective value Veb of the position detection signal Vs is the position detection signal Vs.
When it is lower than the effective value Ve of s, the light emission intensity compensation command circuit 180 decreases the resistance value of the variable resistor 112 and increases the amount of light emitted from the reference light source 12R.

In this way, in the optical position detection device 10, the light detector 3 during the first detection light source lighting operation and the reference light source lighting operation is performed by the light emission intensity compensation command circuit 180 of the position detection unit 50.
The control amounts (drive currents) of the first detection light source 12A and the reference light source 12R are controlled so that the detection amounts by 0 are the same. Therefore, the emission intensity compensation command circuit 180 includes the first detection light source 12A and the reference light source that have the same detection amount by the light detector 30 during the first detection light source lighting operation and the reference light source lighting operation. Information regarding the drive current for the light source 12R exists, and such information is output to the position detection unit 50 as the position detection signal Vg.

Similar processing is performed between the second detection light source 12B and the reference light source 12R, and the position detection signal Vg output from the light emission intensity compensation command circuit 180 is used during the second detection light source lighting operation and the reference. This is information relating to the drive current for the second detection light source 12B and the reference light source 12R so that the detection amount by the photodetector 30 during the light source lighting operation is the same.

(Detection of Z coordinate)
In the optical position detection device 10 of the present embodiment, the first detection light source 12A to the fourth detection light source 1
When 2D lights up at the same time, a light intensity distribution for Z coordinate detection whose intensity monotonously decreases in the normal direction to the first surface 41 is formed on the first surface 41 side (detection space 10R) of the translucent member 40. In such a Z coordinate detection light intensity distribution, the intensity decreases monotonously as the distance from the first surface 41 of the translucent member 40 increases. Therefore, in the Z coordinate detection unit 53 of the position detection unit 50, the photodetector 30 when the reference light source 12R and the first detection light source 12A to the fourth detection light source 12D are alternately turned on.
The Z coordinate of the target object Ob can be detected based on the difference or ratio of the detected values at. In the Z coordinate detection unit 53 of the position detection unit 50, the reference light source 12R and the first detection light sources 12A to 4th.
The driving current for the reference light source 12R and the first detection light source 12A to the fourth detection light source 12D when the detection values of the photodetector 30 when the detection light source 12D is alternately turned on are equal.
The Z coordinate of the target object Ob can be detected based on the difference or ratio with respect to the drive current.
Furthermore, the target object is based on the difference or ratio between the detection value at the photodetector 30 when the first detection light source 12A to the fourth detection light source 12D are sequentially turned on and when the reference light source 12R is turned on. The Z coordinate of Ob can be detected. Furthermore, the first light source for detection 12A to the fourth light source for detection 1
The driving current for the reference light source 12R and the driving current for the detection light sources 12A and 12B when the detection values of the photodetector 30 are equal when the 2D is sequentially turned on and when the reference light source 12R is turned on The Z coordinate of the target object Ob can be detected based on the difference or ratio. In either case, the Z coordinate may be corrected by the XY coordinates of the target object Ob.

Further, the Z coordinate may be detected by providing a detection light source that is separated in the Z-axis direction with respect to the first detection light source 12A to the fourth detection light source 12D. In this case, the X coordinate is detected. A similar differential can be used to detect the Z coordinate.

(Main effects of this form)
As described above, in the optical position detection device 10 according to the present embodiment, the light source driving unit 14 sequentially turns on the four light sources 12 for detection, and during that time, the photodetector 30 detects the detection light reflected by the target object Ob. L3 is received. Therefore, the detection result of the light detector 30 is directly or directly detected by the light detector 30.
If the drive current when the two light sources for detection 12 are differentiated via the position is used, the position detection unit 50
Can detect the position (X coordinate and Y coordinate) of the target object Ob.

Here, the first detection light source 12A, the second detection light source 12B, the third detection light source 12C, and the fourth detection light source 12D are the first detection light source 1 when viewed from the detection space 10R (Z-axis direction).
The distance between 2A and the photodetector 30, the distance between the second detection light source 12B and the photodetector 30, the distance between the third detection light source 12C and the photodetector 30, and the fourth detection light source 12D and the light detection. The distance from the vessel 30 is different.

For this reason, since the center of the differential between the first detection light source 12A and the third detection light source 12C and the difference between the second detection light source 12B and the fourth detection light source 12D are shifted, High detection accuracy can be obtained.

Further, the virtual line Q13 connecting the first detection light source 12A and the second detection light source 12B and the virtual line Q15 connecting the third detection light source 12C and the fourth detection light source 12D are nonparallel. Accordingly, the direction in which the position of the target object Ob is detected using the first detection light source 12A and the second detection light source 12B, and the target object Ob using the third detection light source 12C and the fourth detection light source 12D. The direction in which the position is detected is different. Also, a virtual line Q16 connecting the first detection light source 12A and the fourth detection light source 12D, and a virtual line Q connecting the second detection light source 12B and the third detection light source 12C.
14 is non-parallel. Accordingly, the direction in which the position of the target object Ob is detected using the first detection light source 12A and the fourth detection light source 12D, the second detection light source 12B, and the third detection light source 12 are detected.
The direction in which the position of the target object Ob is detected using C is different.

Therefore, even if the frequency of measurement using the first detection light source 12A, the second detection light source 12B, the third detection light source 12C, and the fourth detection light source 12D is increased, duplicate measurement is not performed. Therefore, according to the optical position detection device 10 of the present embodiment, the position detection accuracy of the target object Ob can be increased by the increase in the measurement frequency.

In this embodiment, since the differential between the two light sources for detection 12 or the differential between the light source for detection 12 and the reference light source 12R is used, the influence of ambient light or the like is automatically corrected. Can do.

Furthermore, since the detection light L2 is infrared light, it is not visually recognized. Therefore, even when the optical position detection device 10 of the present embodiment is applied to a display device, the optical position detection device 10 does not hinder the display.
Can be used for various devices.

[Embodiment 2]
FIG. 7 is an explanatory view schematically showing a main part of the optical position detection device 10 according to Embodiment 2 of the present invention. FIGS. 7 (a) and 7 (b) are diagrams of the optical position detection device 10. FIG. 2 is an explanatory diagram showing a three-dimensional arrangement of components, and an explanatory diagram showing a planar arrangement of components of the optical position detection device 10. FIG. 8 is an explanatory diagram showing a method of specifying the X coordinate and the Y coordinate of the target object Ob from a plurality of results obtained by differential 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.

In FIG. 7, the optical position detection device 10 of the present embodiment is also the light source device 1 as in the first embodiment.
1 includes four or more detection light sources as the plurality of detection light sources 12, and in this embodiment, the number of the detection light sources 12 is four. More specifically, the light source device 11 includes a first detection light source 12A, a second detection light source 12B, and a third detection light source 12C as the plurality of detection light sources 12.
And the fourth light source for detection 12D, and these light sources for detection 12 all direct the light emitting portions 120a to 120d to the light transmitting member 40.

Here, the first detection light source 12A, the second detection light source 12B, the third detection light source 12C, and the fourth detection light source 12D are the first detection light source 1 when viewed from the detection space 10R (Z-axis direction).
The distance between 2A and the photodetector 30, the distance between the second detection light source 12B and the photodetector 30, the distance between the third detection light source 12C and the photodetector 30, and the fourth detection light source 12D and the light detection. The distance from the vessel 30 is different.

More specifically, the distance between the first detection light source 12 </ b> A and the photodetector 30, the second detection light source 12.
B, the distance between the photodetector 30, the distance between the third detection light source 12 </ b> C and the photodetector 30, and the fourth
When the distances between the detection light source 12D and the photodetector 30 are r ₁ , r ₂ , r ₃ , and r ₄ , the distances r ₁ , r ₂ , r ₃ , and r ₄ satisfy the following conditions: r ₄ < r ₁ <r ₂ <r ₃
Is set to

Further, the first detection light source 12A, the second detection light source 12B, the third detection light source 12C, and the fourth detection light source 12D are arranged at unequal angular intervals with the photodetector 30 as the center. That is, the photodetector 30, the first light source for detection 12A, the second light source for detection 12B, and the third light source for detection 12
The central angle when C and the fourth detection light source 12D are respectively connected by a straight line is the following: Θ _AB = the angle formed by the first detection light source 12A, the photodetector 30, and the second detection light source 12B Θ _BC = second Angle formed by detection light source 12B, light detector 30, and third detection light source 12C Θ _CD = angle formed by third detection light source 12C, light detector 30, and fourth detection light source 12D Θ _AD = first detection When defined as the angle formed by the light source 12A, the photodetector 30, and the fourth detection light source 12D, one of the angles Θ _AB , Θ _BC , Θ _CD , Θ _AD is different from the other angles. Yes. In this embodiment, the angles Θ _AB , Θ _BC , Θ _CD , Θ _AD are all different, and the angle Θ _AB
, Θ _BC , Θ _CD , Θ _AD are the following relationships: Θ _CD <Θ _AD <Θ _AB <Θ _BC
Is set to

Further, the virtual line connecting the first detection light source 12A and the second detection light source 12B and the virtual line connecting the third detection light source 12C and the fourth detection light source 12D are non-parallel, and the first Light source for detection 1
The virtual line connecting 2A and the fourth detection light source 12D and the virtual line connecting the second detection light source 12B and the third detection light source 12C are nonparallel.

Even in the optical position detection device 10 having such a configuration, as in the first embodiment, if the differential between the position detection light sources 12 or the differential between the position detection light source 12 and the reference light source 12R is used, FIG.
As shown in, it can be seen that the target object Ob on the geometric line R11 through the position obtained by dividing the first detection light source 12A and the virtual line Q11 connecting the third detection light source 12C ratio P _AC is present. Further, it can be seen that the target object Ob is present on geometric line R12 through the position obtained by dividing the imaginary line connecting the second detection light source 12B and the fourth detection light source 12D in a ratio P _BD. Further, it is possible to obtain an isoline R13 passing through a position obtained by dividing the virtual line Q13 connecting the first detection light source 12A and the second detection light source 12B by a predetermined ratio, and the second detection light source 12B and the third detection light source can be obtained. It is possible to obtain a contour line R14 passing through a position obtained by dividing the virtual line Q14 connecting the light source 12C with a predetermined ratio. Also,
An isoline R15 passing through a position obtained by dividing the imaginary line Q15 connecting the third detection light source 12C and the fourth detection light source 12D by a predetermined ratio can be obtained, and the first detection light source 12A and the fourth detection light source are obtained. It is possible to obtain a contour line R16 passing through a position obtained by dividing the virtual line Q16 connecting the light source 12D by a predetermined ratio.

According to such a configuration, since there is a large amount of information for specifying the position of the target object Ob, the position detection accuracy of the target object Ob can be improved by using a method such as averaging all of a plurality of results obtained by differential. Can be increased.

Here, the first detection light source 12A, the second detection light source 12B, the third detection light source 12C, and the fourth detection light source 12D are the first detection light source 1 when viewed from the detection space 10R (Z-axis direction).
The distance between 2A and the photodetector 30, the distance between the second detection light source 12B and the photodetector 30, the distance between the third detection light source 12C and the photodetector 30, and the fourth detection light source 12D and the light detection. The distance from the vessel 30 is different. Further, the first detection light source 12A, the second detection light source 12B, the third detection light source 12C, and the fourth detection light source 12D are arranged at unequal angular intervals with the photodetector 30 as the center. For this reason, since the center of the differential between the first detection light source 12A and the third detection light source 12C and the difference between the second detection light source 12B and the fourth detection light source 12D are shifted, High detection accuracy can be obtained.

Further, the virtual line Q13 connecting the first detection light source 12A and the second detection light source 12B and the virtual line Q15 connecting the third detection light source 12C and the fourth detection light source 12D are nonparallel. Accordingly, the direction in which the position of the target object Ob is detected using the first detection light source 12A and the second detection light source 12B, and the target object Ob using the third detection light source 12C and the fourth detection light source 12D. The direction in which the position is detected is different. Also, a virtual line Q16 connecting the first detection light source 12A and the fourth detection light source 12D, and a virtual line Q connecting the second detection light source 12B and the third detection light source 12C.
14 is non-parallel. Accordingly, the direction in which the position of the target object Ob is detected using the first detection light source 12A and the fourth detection light source 12D, the second detection light source 12B, and the third detection light source 12 are detected.
The direction in which the position of the target object Ob is detected using C is different. Therefore, even if the frequency of measurement using the first detection light source 12A, the second detection light source 12B, the third detection light source 12C, and the fourth detection light source 12D is increased, duplicate measurement is not performed. Therefore, according to the optical position detection device 10 of the present embodiment, the same effects as those of the first embodiment can be obtained, such as the position detection accuracy of the target object Ob can be increased by the increase in the measurement frequency.

[Other Embodiments]
In the first and second embodiments, the distance between the first detection light source 12A and the photodetector 30, the distance between the second detection light source 12B and the photodetector 30, and the third detection light source 12C and the photodetector 30. Distance with
In making the distances between the fourth detection light source 12D and the photodetector 30 different, all the distances are made different, but a configuration in which one distance is different from the other distances may be adopted. Even in such a configuration, the position detection accuracy of the target object Ob can be increased as compared with the configuration described with reference to FIG.

In the second embodiment, the first detection light source 12A, the second detection light source 12B, the third detection light source 12C, and the fourth detection light source 12D have unequal angular intervals around the photodetector 30. In the configuration, all the angles Θ _AB , Θ _BC , Θ _CD , and Θ _AD are different from each other. However, one angle may be different from the other angles. Even in such a configuration, the position detection accuracy of the target object Ob can be increased as compared with the configuration described with reference to FIG.

In the above embodiment, the virtual line Q13 connecting the first detection light source 12A and the second detection light source 12B and the virtual line Q15 connecting the third detection light source 12C and the fourth detection light source 12D are provided. A non-parallel virtual line Q16 connecting the first detection light source 12A and the fourth detection light source 12D, and a second
The imaginary line Q14 connecting the detection light source 12B and the third detection light source 12C was non-parallel,
Only one may be non-parallel. Even in such a configuration, the position detection accuracy of the target object Ob can be increased as compared with the configuration described with reference to FIG.

In the above embodiment, the number of the detection light sources 12 is four. However, the number of the detection light sources may be five or more, and in this case, four of the five or more detection light sources are included. First light source for detection
The detection light source 12A to the fourth detection light source 12D need only satisfy the above-described configuration.

[Usage example of optical position detection apparatus 10]
With reference to FIG. 9, a robot hand apparatus using the optical position detection apparatus 10 according to the first embodiment of the present invention as a tactile sensor will be described. FIG. 9 is an explanatory diagram of a robot arm provided with a hand device using the optical position detection device 10 according to the first embodiment of the present invention as a tactile sensor, and FIGS. 9A and 9B show the entire robot arm. It is explanatory drawing of this and explanatory drawing of a hand apparatus.

A robot arm 200 shown in FIG. 9A is a device that supplies and removes workpieces and tools to and from a numerically controlled machine tool. The robot arm 200 includes a column 220 that stands upright from a base 290 and an arm 210. Yes. In this embodiment, the arm 210 is attached to the tip of the support column 220 at the first.
A first arm unit 230 connected through a joint 260 and a second arm unit 240 connected to the tip of the first arm unit 230 through a second joint 270 are provided. The support column 220 is rotatable around an axis H 1 perpendicular to the base 290, and the first arm unit 230 is connected to the support column 2.
The first arm 260 can be rotated around the horizontal axis H2 by the first joint 260, and the second arm 240 can be rotated around the horizontal axis H3 by the second joint 270 at the tip of the first arm 230. It is. The hand 450 of the hand device 400 is attached to the tip of the second arm part 240.
Are connected, and the hand 450 can rotate around the axis H <b> 4 of the second arm portion 240.

As shown in FIG. 9B, the hand device 400 includes a hand 450 having a plurality of gripping claws 410 (gripping tools), and the hand 450 is a disk that holds the roots of the plurality of gripping claws 410. A gripping claw holder 420 is provided. In this embodiment, the hand 450 includes a first gripping claw 410A and a second gripping claw 410B as the plurality of gripping claws 410. As shown by the arrow H4, the two grip claws 410 can move in a direction away from each other and a direction in which they approach each other.

When the robot arm 200 configured as described above grips the target object Ob,
After the column 220, the first arm unit 230, and the second arm unit 240 rotate in a predetermined direction to bring the hand 450 closer to the target object Ob (work), the two gripping claws 410 move in a direction approaching each other. Grasping the target object Ob.

Here, the inner surface of the gripping claw 410 that comes into contact with the target object Ob when gripping the target object Ob (workpiece) is the first surface 4 of the translucent member 40 of the optical position detection device 10 described in the above embodiment.
It consists of one. Accordingly, when the gripping claw 410 grips the target object Ob, the optical position detection device 1
0 detects the relative position and position of the target object Ob and the gripping claws 410, and the detection result is fed back to the drive control unit of the gripping claws 410. Therefore, the gripping claw 410 is moved to the target object Ob.
The workpiece can be moved at a high speed, and the workpiece gripping operation can be speeded up.

10..Optical position detector, 10R..Detection space (detection light emission side space), 11..Light source device, 12..Detection light source, 12A..First detection light source, 12B..Second Light source for detection,
12C ··· Third light source for detection, 12D · · Fourth light source for detection, 12R · · · Light source for reference, 30 · · ·
.. Photodetector, 40 .. Translucent member, 50 .. Position detector, 51 .. X coordinate detector, 52.
Y coordinate detector, 53 ... Z coordinate detector, Ob ... Target object

Claims (10)

An optical position detection device including four or more light sources for detection that emit detection light for detecting the position of a target object,
A photodetector for receiving the detection light reflected by the target object located in the emission-side space of the detection light;
A light source driving unit for sequentially lighting the four or more light sources for detection;
A position detection unit that detects the position of the target object based on a light reception result of the photodetector;
Have
Of the four or more light sources for detection, the first light source for detection, the second light source for detection, the third light source for detection, and the second light source arranged in the circumferential direction around the photodetector when viewed from the exit side space. 4. The optical position detection device according to claim 1, wherein the light sources for detection have different distances from the photodetector. When viewed from the exit side space, the first detection light source, the second detection light source, the third
2. The optical position detection device according to claim 1, wherein the detection light source and the fourth detection light source are all different in distance from the photodetector. When viewed from the exit side space, a virtual line connecting the first detection light source and the second detection light source, and a virtual line connecting the third detection light source and the fourth detection light source are: The optical position detection device according to claim 1, wherein the optical position detection device is non-parallel. A virtual line connecting the first detection light source and the fourth detection light source and a virtual line connecting the second detection light source and the third detection light source when viewed from the emission side space, The optical position detection device according to claim 3, wherein the optical position detection device is non-parallel. When viewed from the exit side space, the first detection light source, the second detection light source, the third
5. The optical position detection device according to claim 1, wherein the detection light source and the fourth detection light source are arranged at equiangular intervals with respect to the photodetector. 6. . When viewed from the exit side space, the first detection light source, the second detection light source, the third
5. The optical position according to claim 1, wherein the light source for detection and the fourth light source for detection are arranged at unequal angular intervals around the light detector. 6. Detection device. The position detection unit may include a part of the first detection light source, the second detection light source, the third detection light source, and the fourth detection light source based on a light reception result of the photodetector. 7. The optical position detection according to claim 1, wherein the position of the target object is detected based on a result obtained by differentiating a detection light source and another part of the detection light source. apparatus. A reference light source that emits reference light incident on the photodetector without going through the exit-side space;
The position detection unit may include a part of the first detection light source, the second detection light source, the third detection light source, and the fourth detection light source based on a light reception result of the photodetector. 7. The optical system according to claim 1, wherein the position of the target object is detected based on a plurality of results obtained by differentiating a combination of the detection light source and the reference light source. Position detection device. The position detection unit detects the position of the target object in the emission direction of the detection light based on a light reception result of the light detector when all of the four or more light sources for detection are turned on simultaneously or sequentially. The optical position detection device according to claim 7 or 8, characterized in that: The optical position detection device according to any one of claims 1 to 9, wherein the detection light is infrared light.