JPH0346042B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a light-receiving sensor structure in a photoelectric measuring instrument for measuring the dimensions, displacement, etc. of an object, and in particular, to a concentric two-element structure consisting of a first light-receiving element in the center and a second annular light-receiving element surrounding the first light-receiving element. A light-receiving sensor consisting of a light-receiving element receives transmitted light or reflected light from the object to be measured, converts it into different electrical signals corresponding to changes in the amount of received light, and measures the dimensions of the object to be measured based on these electrical signals. This paper relates to improvements in the structure of light-receiving sensors in photoelectric measuring instruments.

[Conventional technology]

Conventionally, this type of photoelectric measuring instrument, such as a projector, illuminates the object to be measured on a stage with parallel light beams, and projects a projected image of the object on a screen based on the transmitted or reflected light. This method uses the formed image to measure the dimensions and shape of the object to be measured, but the edges of the image of the object to be measured that are projected onto the screen generally have so-called smudges, and therefore , move the object to be measured on the stage,
It is difficult to accurately read measurement values from the coincidence of the image formed on the screen and the hairline. In order to solve this problem, conventionally, the edge of the image is moved relative to the light-receiving element. There is a device that detects the edge of a projected image by comparing a change in the magnitude of an electric signal output from an element with a reference voltage. However, this method has problems in that it is greatly affected by noise such as ambient light, and the measurement accuracy is greatly reduced due to fluctuations in the signal or reference voltage obtained from the light receiving element. Furthermore, the light receiving element is moved relative to the boundary (edge) of the projected image on the screen, the output signal at that time is second-order differentiated to obtain a waveform signal, and the edge is determined by comparing this with a reference voltage. However, depending on the speed of relative movement between the light receiving element and the projected image, the position of the detected edge may vary, and as mentioned above, measurement accuracy may decrease due to fluctuations in the reference voltage. The problem is that it is large. Furthermore, two light-receiving elements are arranged and moved relative to the edge of the projected image, a waveform signal is obtained from the multiple output signals obtained by this, and by comparing this with a reference voltage. There are devices that detect edges, but as mentioned above, the measurement becomes extremely unstable due to relative changes in the output signal obtained from the light receiving element and the reference voltage, level fluctuations, etc. There are problems in that the area is narrow, measurement modes are limited, and the sensor section or circuit section is complicated. In particular, in projectors, the brightness of the projected image on the screen changes due to fatigue of the irradiation light source lamp, lens characteristics of the projection system, and ambient light, and changes in the brightness of the projected image due to switching of the projection magnification. Furthermore, as a condition on the measurer's side, for example, the optimum brightness for the work differs depending on the person's eye color (which differs depending on the race), so this must be selected appropriately. If the range of application to the illuminance of the irradiated light is narrow, the performance of the projector will be reduced as a result. Further, in the conventional edge detection method, if the projected image is out of focus, the output waveform of the light receiving element becomes gentle, so that accurate edge detection cannot be performed. This problem is common not only to projectors but also to edge detection in photoelectric measuring instruments that detect transmitted light or reflected light to directly or indirectly measure the dimensions of objects to be measured. This is a problem. On the other hand, as disclosed in JP-A No. 58-173408, for example, there is an optical measuring instrument for directly or indirectly measuring the dimensions of an object by detecting transmitted light or reflected light. In the edge detection device, the four edge detectors are arranged in a plane substantially parallel to the plane of movement so as to generate at least two sets of phase shift signals based on the brightness and darkness that occurs when moving relative to the object to be measured.
a sensor consisting of two light receiving elements, first and second calculation means for calculating the difference between the phase shift signals of each set, and a third calculation means for calculating the difference between the output signals of the first and second calculation means. and a fourth calculating means for calculating the sum, and outputting a cross signal between the output signal of the third calculating means and a reference level, which occurs while the output signal of the fourth calculating means is at a predetermined level. A device equipped with a detection means has been proposed. This edge detection device has a simple configuration and is capable of measuring without being affected by the light intensity irradiating the measurement target, noise such as ambient light during measurement, fluctuations in the output signal of the light receiving element, or the reference voltage. The edges of the object can be detected, and even if the projected image is out of focus in the projector, the edges can be detected accurately.Furthermore, by directly processing the analog signal from the light receiving element, , it has the advantage of being able to detect edges of the object to be measured. However, in the edge detection device disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 58-173408, since the sensor is formed of four light receiving elements arranged in a shape, it is difficult to project images on a screen in a projector, for example. When moving relative to the image, if the boundary line of the light-receiving element coincides with the direction of movement, the edges of the projected image may not be detected, which poses a problem in that the direction of movement of the sensor relative to the projected image is restricted. In contrast, the present applicant
proposed a light-receiving sensor consisting of a concentric two-element light-receiving element consisting of a central first light-receiving element and an annular second light-receiving element surrounding it. This light-receiving sensor has the advantage that there is no variation in sensitivity due to differences in the sensor movement direction, and therefore there is no restriction on the movement direction of the sensor with respect to the projected image. However, such a concentric two-element light-receiving element sensor has a small S/N ratio of the electric signal extracted, and the sensor itself is large. Furthermore, when the curvature of the object to be measured is large, There is a problem that it may not be possible to detect the That is, as shown in FIG. 7, the light receiving sensor 1 consisting of concentric two-element light receiving elements is
The signal lead line 3 of the light receiving element 2 is connected to the first light receiving element 2.
An annular gap 5 between the outer periphery of the first light receiving element 2 and the second light receiving element 4 is
Since the distance in the radial direction of the sensor is approximately 200 μm, the size of the light receiving sensor 1 is large. For this reason, the minimum dimension of the object that can be measured becomes large. On the other hand, it is possible to reduce the size of the light receiving sensor 1 itself by reducing the light receiving area of the first light receiving element 2 and the second light receiving element 4, but if this is done, the S/N ratio will decrease. Therefore, in order to maintain a certain measurement accuracy, it is impossible to reduce the light receiving area. Therefore, once the light-receiving area is determined from the required measurement accuracy, the size of the chip of the light-receiving sensor is determined by adding the minimum width of the gap 5. Therefore, with the conventional structure, it has been difficult to reduce the size beyond a certain level. In addition, as mentioned above, since the distance of the gap 5 is large, when the light receiving area of the first light receiving element 2 and the second light receiving element 4 is set to the minimum necessary minimum, the distance of the gap 5 with respect to the light receiving area becomes excessive, and therefore, if the curvature in the contour of the image to be measured is large, the measurement accuracy will be reduced. That is, as shown in FIG. 8A, when the curvature of the image 7 is small, the difference ΔS in the light-receiving area between the first light-receiving element 2 and the second light-receiving element 4 is small; The amount of light received by the elements is almost the same. On the other hand, as shown in FIG. 8B, when the curvature of the image 7 is large, the difference between the light-receiving area of the first light-receiving element 2 and the light-receiving area of the second light-receiving element 4 is ΔS=ΔS ₂ −
ΔS ₁ increases, the differential signal based on the outputs of the first light receiving element 2 and the second light receiving element 4 becomes abnormal, and measurement accuracy decreases. Furthermore, the first light-receiving element 2 and the second light-receiving element 4 output electrical signals according to the amount of light received, and these electrical signals are transmitted to the first light-receiving element 2 and the second light-receiving element 4, respectively. It is led out to the outside by connected signal lead lines 3 and 8. Here, the signal deriving line 3 of the first light receiving element 2 passes through the light receiving surface side of the second light receiving element 4 to the second light receiving element 4.
The wires are routed to the outside of the Therefore, the signal lead line 3 and the second light receiving element 4
In order to avoid interference between the light-receiving surface of the light-receiving surface and the surface to be measured or the object to be measured, the facing clearance of the signal leader line 3 to these must be increased, and the light-receiving surfaces of the light-receiving elements 2 and 4 must be placed far away from the object to be measured. separated. Therefore, when the brightness of the object to be measured or the surface of the object to be measured is kept constant, a problem arises in that the effective amount of light received by the light receiving sensor 1 decreases and the sensor sensitivity decreases. Further, since the signal lead line 3 is wired to cover the light receiving surface of the second light receiving element 4, a shadow is caused by the signal lead line 3 on the second light receiving element 4, and therefore the output of the light receiving sensor 1 is There is a problem that the S/N ratio decreases.

[Problems to be solved by the invention]

The present invention has been made in view of the above problems, and there is no restriction on the relative movement direction of the sensor with respect to the projected image, and edges can be reliably detected in any direction. It is an object of the present invention to provide a light-receiving sensor structure for a photoelectric measuring instrument that is smaller in size, has an improved S/N ratio, and is capable of detecting edges of a measuring object having a small curvature.

[Means to solve the problem]

This invention receives transmitted light or reflected light from an object to be measured by a light-receiving sensor consisting of a concentric two-element light-receiving element, which is a first light-receiving element in the center and a second annular light-receiving element surrounding it. In a light-receiving sensor structure in a photoelectric measuring instrument that converts into different electrical signals corresponding to changes in quantity and measures the dimensions of the object based on these electrical signals, the radiation direction of the first light-receiving element at a constant angle from the center. A sector-shaped area extending to the outer periphery is defined as a first dead zone, and a part of the second light-receiving element adjacent to the radially outer side of the first dead zone and serving as an expanded part of the sector-shaped area is defined as an inner part. A second dead zone extends from the periphery to the outer circumference, and the signal lead line of the first light receiving element is connected to the first light receiving element in the first dead zone, and the signal lead line of the first light receiving element is connected to the first light receiving element through the second dead zone. The above object is achieved by arranging the light receiving element so as to lead it out to the outside of the light receiving element. Further, the present invention achieves the above object by forming the second dead zone as a space formed by cutting out a part of the second light receiving element. Further, in the present invention, the first dead zone is a space formed by cutting out a part of the first light-receiving element, and the signal lead-out line is connected to the first light-receiving element within the space. By doing so, the above purpose is achieved. Further, in the present invention, the signal lead-out line is connected to the first
The above object is achieved by wiring the light receiving element and the second light receiving element at a position retracted from the light receiving surfaces. Further, the present invention achieves the above object by making the light receiving surfaces of the first light receiving element and the second light receiving element flush. Furthermore, the present invention achieves the above object by making the effective areas of the light receiving surfaces of the first light receiving element and the second light receiving element the same.

[Effect]

In this invention, since the signal lead-out line of the first light-receiving element is connected to the first light-receiving element at the first dead zone formed in the first light-receiving element, the line between the first light-receiving element and the second light-receiving element is By reducing the gap, it is possible to downsize the entire light receiving sensor, and
It is possible to measure a measurement object with a small curvature, and furthermore, it is possible to further reduce the minimum measurable dimension and expand the measurement range. Further, since the dead zone is formed in a fan shape that radiates out from the center of the first light receiving element, for example, when the edge of the object to be measured passes through the center, the first
The ratio of the amount of light received by the second light-receiving element and the second light-receiving element is maintained constant regardless of the moving direction of the light-receiving sensor. Furthermore, since the signal lead line does not cover the light-receiving surface of the second light-receiving element, there is no shadow on the light-receiving surface of the second light-receiving element, which increases the S/N ratio of the sensor output signal. I can do it. Furthermore, in this invention, the pair of light receiving elements constituting the sensor are arranged concentrically, so that the boundary lines of the light receiving elements do not coincide with the moving direction, and the relative movement of the sensor with respect to the object to be measured is prevented. Edges are reliably detected regardless of direction.

【Example】

Embodiments of the present invention will be described below with reference to the drawings. In this embodiment, the present invention is applied to an edge detection device for a projector, and as shown in FIGS. The measurement target 16 on the stage 14 is irradiated from below the stage 14 or from above the stage 14 via another optical path, and the projection lens 18 is set based on the transmitted light or reflected light. The object to be measured 1 is placed on the screen 10 through the
6 projection image 16A is formed, and this projection image 1
6A is used in the edge detection device in the projector 20 for indirectly measuring the dimensions of the measurement object 16, etc., and generates a phase shift signal based on the brightness and darkness that occurs when moving relative to the projected image 16A. Including first and second light receiving elements 22A and 22B arranged concentrically in a plane substantially parallel to the moving plane,
In the light receiving sensor 24, the level of the sensor output signal based on the output of both the light receiving elements 22A, 22B at the sensor output terminals 23A, 23B is the same value at each of the bright and dark times that occur during the relative movement. First light receiving element 22
A part adjacent to the outer periphery is the first dead zone 26A
In addition, a part of the second light receiving element 22B adjacent to the outside in the radial direction of the first dead zone 26A is defined as a second dead zone 26B from the inner circumference to the outer circumference, and the first dead zone 22A Signal leader line 2
8 in the first dead zone 26A.
It is connected to the light receiving element 22A and is arranged so as to be led out to the outside of the second light receiving element 22B through the second dead zone 26B. Here, the first dead zone 26A and the second dead zone 26B are part of the same fan-shaped area that extends in the radial direction at a constant angle from the center of the first light receiving element 22A. The light receiving element 22B is cut out and formed in the space. The signal lead line 28 is connected to the light receiving element 22A within the first dead zone 26A, and is wired to pass through the second dead zone 26B, which is a recess, and reach the outside of the second light receiving element 22B. ing. Here, the first light receiving element 2 of the signal lead line 28
As shown in FIG. 4, the connection end 29 on the 2A side extends from a fan-shaped connection tip 29A that fills the fan-shaped first dead zone 26A, and from the proximal end side of this connection tip 29A. The inside of the second dead zone 26B is
It consists of a small-diameter pull-out portion 29B that penetrates the light-receiving element 22B so as not to touch the end thereof, and this pull-out portion 29
The main body of the signal lead line 28 is connected to the outer end of B. In the figure, reference numeral 30 indicates a chip to which the first light receiving element 22A and the second light receiving element 22B are attached, and 32 indicates a signal lead line of the second light receiving element 22B. Here, the gap 34 between the first light receiving element 22A and the second light receiving element 22B may be about 10 μm without being filled with an insulating material. Further, in this embodiment, the first light receiving element 2
The light-receiving surfaces 35A and 35B of the light-receiving sensors 2A and 22B are flush with each other so as to be on the same plane orthogonal to the central axis of the light-receiving sensor 24. Furthermore, these light receiving surfaces 35A and 35B are designed to have the same effective light receiving area. Here, the connection end portion 29, which is a part of the signal lead line 28, is arranged at a position retracted from the light receiving surfaces 35A, 35B of the first light receiving element 22A and the second light receiving element 22B. The edge detection device includes the light receiving sensor 24
A difference calculator 36 is connected to the sensor output terminals 23A and 23B and calculates the difference between the phase shift signals, and a differential output signal of the difference calculator 36 is compared with high-level and low-level reference signals. , forming a hold signal to hold one sensor signal among the sensor output signals when the differential output signal is between high and low levels, and forming a hold signal between the high hold signal and the low hold signal. A region signal generator 3 that outputs a signal in a specific region including the cross point of the phase shift signal and the reference level signal when there is an output signal.
8, and a detection means 40 for outputting a cross signal between the differential output signal of the difference calculator 36 and a preset reference level signal while the signal is being output from the region signal generator 38. It is something that As shown in FIG. 1, the sensor is provided integrally with a transparent plate 42 that is slidably placed on the upper surface of the screen 10 of the projector 20 in parallel with the screen 10, and is mounted together with the transparent plate 42. , being able to move. Here, the sensor 24 includes, in addition to the first and second light receiving elements 22A and 22B, current-voltage converters 43A and 43B for converting the outputs of the first light receiving element 22A and the light receiving element 22B; Amplifiers 46A and 46B for amplifying the output voltage
It is equipped with These amplifiers 46A and 46B are completely dark,
The offset is adjusted to cancel the dark voltage of the first and second light receiving elements 22A, 22B, and the sensor output terminals 23A, 2 are fully bright.
The gain is adjusted so that the output at 3B is at the same level. The area signal generator 38 is connected to the difference calculator 36.
A first comparator 44A compares the differential output signal with a high level reference signal and outputs a hold signal when the differential output signal is lower than the high level; a second comparator 44B that outputs a hold signal when the dynamic output signal is higher than the low level; and a second comparator 44B that outputs a hold signal when the dynamic output signal is higher than the low level; First and second sample and hold circuits 46A and 46B that hold the sensor output signal b and sample the sensor output signal b when the hold signal is not input, and these first and second sample and hold circuits 46A, A third comparator 48A that compares the output signal of 46B with the sensor output signal b and outputs a signal when the output signal is smaller than the sensor output signal b; A fourth comparator 48B outputs a signal when the output signal is larger than the sensor output signal b, and a region signal when only one of the third and fourth comparators 48A, 48B outputs a signal. An exclusive OR gate 50 that generates . The detection means 40 also includes a comparator 52 that compares the output signal of the difference calculator 36 with a reference level signal and outputs a signal when the two match, that is, at a cross point. Edge detection is performed only when a pulse signal generator 54 generates an edge pulse signal based on the signal output from the pulse signal generator 54, and a signal is output from both this pulse signal generator 54 and the area signal generator 38. An AND gate 56 that outputs a signal is provided. The output signal from this AND gate 56 is adapted to output an edge detection signal to a counter 60 of a displacement detection device 58 interlocked with the stage 14. This displacement detection device 58 is composed of an encoder 62 that is linked to the document stage 14 and generates a pulse signal according to the amount of movement thereof, and the counter 60 that reads the pulse signal output from the encoder 62. There is. This counter 60 is configured to output its read value to a storage device 64 when an edge detection signal is input from the AND gate 56. Next, the operation of the above embodiment will be explained. Measurement object 16 imaged on screen 10
The projected image 16A is moved relative to the sensor 24 in one direction so that the edge of the projected image 16A crosses the sensor 24. When the projected image 16A approaches the sensor 24 relatively and passes through it, it is obtained by the first and second light receiving elements 22A and 22B, and is transmitted to the amplifier 46 via the current-voltage converters 43A and 43B.
A, 46B, the output signals generated from the sensor output terminals 23A, 23B are equal amplitude, out-of-phase signals, as indicated by a and b in FIG. 5A. As shown in FIG. 5B, these output signals are calculated by the difference calculator 36 to give c=a−b, and are sent to the first and second comparators 44A and 44B of the area signal generator 38, respectively. is input. On the other hand, the output signal b from the sensor output terminal 23B is also input to the first and second comparators 44A and 44B of the area signal generator 18, respectively. As shown in FIG. 5C, the first comparator 44A compares the reference voltage Vref+ and the input signal c, and when the signal c is smaller than Vref+, the first comparator 44A transfers the sampling signal b to the first sample hold circuit. Output to 46A. Further, as shown in FIG. 5D, the second comparator 44B compares the input signal c and the reference voltage Vref-, and determines whether the signal c is
When it is smaller than Vref-, the sampling signal e is output to the second sample hold circuit 46B. Note that the first and second comparators 44A, 44B
has a hysteresis characteristic as shown in FIG. 5B to prevent chattering. The first and second sample and hold circuits 46
A, 46B samples the sensor output signal b when the first comparator 44A outputs the sampling signal d and when the second comparator 44B outputs the sampling signal e, and also samples these sampling signals. When d and e are not output, the signal values at the final sampling time are held. Therefore, these sample and hold circuits 46A,
46B is configured to output a high hold signal f and a low hold signal g to the third comparator 48A and the fourth comparator 48B, respectively, as shown by the broken line and the dashed line in FIG. 5E. These third comparator 48A and fourth comparator 4
8B indicates the input high hold signal f and low hold signal g as shown in FIG. 5F and G.
is compared with the sensor output signal a, and when the high hold signal f and the low hold signal g are larger than the sensor output signal b, the signals h and i are outputted to the exclusive OR gate 50, respectively. This exclusive OR gate 50 is the 5th
When a signal is output from only one of the comparator 48A and the fourth comparator 48B, the digital signal j of "1" is output as shown in FIG. 5H and FIG.
Output. On the other hand, the differential output signal c output by the difference calculator 36 is input to the comparator 52 of the detection means 40, and this comparator 52 receives the differential output signal c as shown in FIG. When c crosses the reference level signal of 0, a digital signal k of "1" is output. Based on the output of the comparator 52, the pulse signal generator 54 generates a pulse signal e as shown in FIG.
is output to the AND gate 56. Pulse signal l from the pulse signal generator 54
and the digital signal j from the exclusive OR gate 50 are input to an AND gate 56, which, when both input signals are "1", performs the following, as shown in FIG. 5K, for example:
A pulse signal m of 10 μSec is output, and at this point,
This is to detect edges of the projected image 16A. The above is for the case where the measurement was performed normally, but depending on the measurement environment, the differential output signal c may be temporarily affected by optical or electrical noise, vibration of the stage 14, etc. fluctuations may occur. In this case, in the conventional edge detection device,
Edge detection may become impossible because the area signal cannot be generated or the area signal is output at a cross point between the differential output signal and the reference signal, that is, at a point other than the edge position. Ta. In the above embodiment, when the sensor output signals a and b oscillate once about the vibration center line 66 due to the vibration of the stage 14 as shown in FIG. b
becomes as shown in FIG. 6A. In the case of conventional edge detection devices, the vibrations and fluctuations of the signals themselves to be detected, such as differential output signals, are not considered, so these sensor output signals a and b
A false signal is often generated when the vibration center line 66 falls at the location of the vibration centerline 66. In this embodiment, as shown in FIG. 6E, the high hold signal f fluctuates due to the vibration of the sensor 24, and in response, the output signal h of the third comparator 48A is output. Further, although a digital signal j is also output from the exclusive OR gate 50, the area signal j itself output from the exclusive OR gate 50 is not shifted by the vibration. That is, even if vibration or the like occurs in the differential output signal, the area including the cross point can be reliably specified without being affected by this. Therefore, the region signal j is output at the time when it overlaps with the pulse signal l based on the output signal k from the comparator 52, and as a result, the edge signal m is output from the AND gate 56. The edge signal m is input to a counter 60 in the displacement detection device 58, and the counter 60 outputs the read value at the time when the edge signal m is input to the storage device 64, and The position of the edge will be detected. The signals stored in the storage device 64 will be output to another computing device, printed out, or displayed on a display. In this embodiment, the signal lead line 28 of the first light receiving element 22A is connected to the first light receiving element 22A in the first dead zone 26A formed in the first light receiving element 22A.
2A, so the first light receiving element 22A
A signal lead line 28 is connected between the
No space is required to connect. Therefore, the outer diameter of the second light-receiving element 22B can be reduced without reducing its light-receiving area, and the overall size of the light-receiving sensor 24 can be reduced. Therefore, the size of the chip 30 on which the first light receiving element 22A and the second light receiving element 22B are attached can be a square with each side being 1 mm. Furthermore, since the overall outer diameter of the first and second light-receiving elements 22A and 22B can be made smaller, the minimum measurable external dimension of the object to be measured can be reduced, and when the curvature of the object to be measured is small. It is also possible to detect edges etc. Further, in the above embodiment, the first light receiving element 22A
The signal lead line 28 is led out to the outside via the lead part 29B passing through the second dead zone 26B formed by cutting out the second light receiving element 22B. There is no shadow on the light-receiving surface 35B of the light-receiving element 22B, and therefore the S/N ratio of the sensor output can be improved. Furthermore, the signal lead line 28 may be wired so as to float above the light receiving surface 35B of the second light receiving element 22B,
In addition, in order to avoid interference between the screen 10 and the signal lead line 28, the first and second light receiving elements 22A,
22B light receiving surfaces 35A, 35B and screen 1
Since there is no need to provide a large clearance between the first and second light receiving elements 22A,
The light receiving surfaces 35A and 35B of 22B are
0 allows for relative movement by approaching
Therefore, the amount of light received can be increased and the S/N ratio can be improved. Here, in the above embodiment, the measurement object 16
However, in the case of a material that cannot completely block light, such as a translucent glass product, Fig. 5A and Fig. 6A
As shown in the following, the sensor output signals a and b in the dark area are set to "1" in bright light and "0" in complete darkness.
It is a value larger than 0 and close to "1". In this case, when these sensor output signals a or b compare themselves with the reference voltage Vref-, the reference voltage Vref-
It may not be possible to obtain the intersection point with Vref-, and therefore it may not be possible to obtain the area signal. In this embodiment, the region signal is processed by the difference calculator 3.
6 differential output signals, that is, c=a−b, the area signal can be reliably obtained even if the measurement object 16 is a semitransparent material. Further, in this embodiment, the first and second light receiving elements 22A and 22B that constitute the sensor 24 are
Since the sensor output terminals 23A and 23B are formed concentrically and the output levels of the signals generated by these are equal, the boundary line between the first and second light-receiving elements 22A and 22B and the direction of movement are the same. Projection image 1 of sensor 24 without matching
Regardless of the direction of movement relative to 6A, a uniform output signal can be obtained, so there is no restriction on the direction of movement of the sensor relative to the object to be measured, and edge detection can be performed with high precision. . Here, if the directions of the first dead zone 26A and the second dead zone 26B match the moving direction of the sensor 24, the sensor output decreases;
is formed in the radial direction only in one direction from the center of the first light receiving element 22A, so light can be received at the opposite side of the first and second dead zones 26A and 26B, and therefore the movement of the sensor 24 is direction and first
Edges can be detected even if the directions of the second dead zones 26A and 26B match. In addition, since the dead zones 26A and 26B are formed in the radial direction as described above, as long as the edge passes through the center of the first light receiving element 22A, the ratio of the light receiving areas of the first and second light receiving elements 22A and 22B is equal to the sensor. There is no change depending on the direction of movement. Therefore, there is no restriction on the direction of sensor movement. Further, in the embodiment, the first and second light receiving elements 22A, 22B have the same light receiving area, so that the sensor output terminals 23A, 23
B are set to be equal, but this only requires that the output signals at the sensor output terminals 23A and 23B be at the same level; therefore,
Light receiving elements 22A, 22B and sensor output terminal 23
Place an amplifier between A and 23B, or
Both sensor output terminals 2 without installing an amplifier
The output levels of 3A and 23B may be made equal. Furthermore, in the embodiment described above, the projected image 16A is moved relative to the sensor 24 by moving the stage 14;
The sensor 24 may be moved relative to A. Furthermore, in the above embodiment, the first light receiving element 22
A gap 34 is formed between A and the second light receiving element 22B to prevent them from coming into contact with each other.
For example, the two may be placed in contact with each other via a film-like insulator. In this case, there is no need for a gap between the two. Further, although the above embodiment is for measuring the edge of a projected image on a screen of a projector, the present invention is not limited to this, and the present invention is not limited to this, but can be performed by detecting transmitted light or reflected light, It is generally applied to a sensor structure in a photoelectric measuring device for directly or indirectly measuring the dimensions of an object to be measured.

【Effect of the invention】

Since the present invention is configured as described above, the concentric type 2
In a light-receiving sensor consisting of elemental light-receiving elements, it is possible to reduce the size and improve the S/N ratio, reduce the minimum measurable dimension of the object to be measured, and furthermore, detect objects with small curvature. It also has the excellent effect of making it possible to

[Brief explanation of drawings]

Fig. 1 is an optical system diagram showing an embodiment in which the light receiving sensor structure of the photoelectric measuring instrument according to the present invention is implemented in a projector, Fig. 2 is a block diagram showing the configuration of the same embodiment, and Fig. 3 is The first in the same example
FIG. 4 is a sectional view taken along the - line in FIG. 3; FIG. 5 is a line diagram showing the process of signal processing in the same embodiment; Fig. 6 is a diagram showing the signal processing process when the sensor output fluctuates in the same embodiment, Fig. 7 is a plan view showing the relationship between the light receiving element and the signal lead line in the earlier application by the present applicant, and Fig. 8 is the same diagram. FIG. 3 is a plan view showing the relationship between a light receiving element and a measurement target. 16...Measurement object, 16A...Projected image, 22A
...First light receiving element, 22B... Second light receiving element, 24...
Sensor, 26A...first dead zone, 26B...second
dead zone, 28...signal leader line, 29...connection end,
29A... Connection tip, 29B... Drawer part, 30... Chip, 35A, 35B... Light receiving surface.

Claims (1)

[Scope of Claims] 1. A light-receiving sensor consisting of a concentric two-element light-receiving element consisting of a first light-receiving element in the center and a second annular light-receiving element surrounding the first light-receiving element, which receives transmitted light or reflected light from an object to be measured. In the light receiving sensor structure of a photoelectric measuring instrument that converts the received light into different electrical signals corresponding to changes in the amount of light received and measures the dimensions of the object to be measured based on these electrical signals, the first light receiving element is set at a certain angle from the center. A fan-shaped area extending in the radial direction and reaching the outer periphery is a first dead zone, and
A part of the second light-receiving element adjacent to the outside in the radial direction of the first dead zone and serving as an expanded portion of the fan-shaped area is defined as a second dead zone extending from the inner circumference to the outer circumference of the first light-receiving element. A photoelectric measuring instrument in which a signal lead line is connected to the first light-receiving element in the first dead zone and is arranged so as to be led out to the outside of the second light-receiving element through the second dead zone. Light receiving sensor structure. 2. The light receiving sensor structure in a photoelectric measuring instrument according to claim 1, wherein the second dead zone is a space formed by cutting out a part of the second light receiving element. 3. The first dead zone is a space formed by cutting out a part of the first light receiving element, and
3. The light receiving sensor structure in a photoelectric measuring instrument according to claim 1, wherein the signal lead-out line is connected to the first light receiving element within the space. 4. According to any one of claims 1 to 3, wherein the signal lead-out line is wired at a position retracted from the light-receiving surfaces of the first light-receiving element and the second light-receiving element. A light receiving sensor structure in the photoelectric measuring device described. 5. A light-receiving sensor in a photoelectric measuring instrument according to any one of claims 1 to 4, wherein the light-receiving surfaces of the first light-receiving element and the second light-receiving element are flush with each other. structure. 6. A light-receiving sensor structure in a photoelectric measuring instrument according to any one of claims 1 to 5, wherein the effective areas of the light-receiving surfaces of the first light-receiving element and the second light-receiving element are the same.