JPH0436609A - Displacement detector - Google Patents

Abstract

PURPOSE:To detect displacement such as the position and inclination of an object with small-sized constitution without being limited with an object by outputting a signal corresponding to the difference between the outputs of the inside and outside photodetectors of a sensor. CONSTITUTION:When the object 6 is irradiated with light from a light source, the light is received by the sensor 14 through an image forming lens 15. The signal corresponding to the difference between the output of the inside photodetector 21 of the sensor 14 and the output of the photodetector 22 is adjusted to a reference value. In this state, when the object 6 is farther than a focus position, the light receiving quantity of the outside photodetector 22 is increased and when the object 6 is in front of the focus position, on the other hand, the light receiving quantity of the outside photodetector 22 is decreased, so a displacement detecting circuit 31 finds the difference between the outputs of both and outputs the signal corresponding to the difference, so that the position of the object 6 can be detected. When the object 6 slants to an optical system, the outputs of one divided photodetecting element and the other divided photodetector become different, so the inclination of the object 6 can be detected from the signal corresponding to the difference.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a displacement detection device that detects displacements such as the position and inclination of an object in a non-contact manner. Specifically, a displacement detection device that irradiates light onto an object, receives the light with a sensor consisting of a light-receiving element, converts it into an electrical signal, and detects the displacement of the object, such as its position or inclination, based on this signal. Regarding.

[Background technology]

As a device for non-contact detecting the position of an object, such as a triangular distance measuring electronic distance meter used in the autofocus mechanism of a camera, and a Michelson interferometer, there are known devices.

The former type of electronic rangefinder has a pair of distance-measuring objective lenses placed a baseline length apart, and a light-receiving element corresponding to each lens. The distance (position) of the object is detected from the position of the lens when both outputs match.

The latter Michelson interferometer splits the laser light emitted from the laser source into two optical paths with a beam splitter, reflects each light with an 11th and 2nd reflecting mirror, and returns them to the same optical path again. The light is made incident on the photodetector through the . Here, adjustment is made in advance so that when the reflected light from both mirrors enters the photodetector, the wavefronts of the reflected light from both mirrors coincide completely. Therefore, for example, if the second reflecting mirror moves together with the object, interference fringes are generated depending on the distance of movement, and the position of the object can be detected from the number of the fringes.

[Problem to be solved by the invention]

However, the former type of electronic distance meter has the disadvantage that the device becomes larger because the pair of distance measuring objective lenses must be placed apart by the base line length.

Furthermore, in the latter Michelson interferometer, one of the reflecting mirrors must be attached directly or indirectly to the target object, so the target objects are limited. For example, it is impossible to detect each part on the curved surface of the workpiece.

The purpose of the present invention is to solve all of these conventional problems and to provide a displacement sensor that is compact and capable of detecting displacements such as the position and inclination of an object without being limited by the object. The object of the present invention is to provide a detection device.

[Means to solve the problem]

Therefore, in the present invention, an optical system including a light source and a lens for irradiating light from the light source onto an object, an inner light receiving element having a circular outer periphery, and an annular outer light receiving element arranged concentrically with the inner light receiving element are provided. and a sensor constituted by divided light receiving elements in which either the inner light receiving element or the outer light receiving element is equally divided into at least four pieces in the circumferential direction; an imaging lens that forms an image of the irradiated light; a displacement detection circuit that outputs a signal corresponding to the difference between the output of the inner light receiving element and the output of the outer light receiving element of the sensor; and one of the divided light receiving elements of the sensor. , a tilt detection circuit that outputs a signal corresponding to the difference between the output of the divided light receiving element on one side and the output of the divided light receiving element on the other side, which are divided by the axes that pass through the core of the sensor and are orthogonal to each other. It is characterized by the following:

The optical system includes a light source and a lens that irradiates the object with light from the light source, an inner light-receiving element having a circular outer periphery, and an annular outer light-receiving element arranged concentrically with the inner light-receiving element. , and among these (III') a sensor constituted by an inner divided light receiving element and an outer light receiving element in which the light receiving element and the outer light receiving element are divided into at least two equal parts in the circumferential direction; an imaging lens that forms an image of the irradiated light; a displacement detection circuit that outputs a signal corresponding to the difference between the output of the inner light-receiving element and the output of the outer light-receiving element of the sensor; and an inner divided light-receiving element of the sensor; Outputs a signal corresponding to the difference between the output of the split light receiving element on one side and the output of the split light receiving element on the other side, which are divided by the mutually orthogonal axes passing through the center of the sensor on the same side among the outer light receiving elements. The present invention is characterized by comprising a tilt detection circuit.

[For production]

When light from a light source is irradiated onto an object through a lens, the light is received by a sensor through an imaging lens.

Here, for example, in a state where the object is located at the focus position of the lens of the optical system, the signal corresponding to the difference between the output of the inner light-receiving element and the output of the outer light-receiving element of the sensor becomes the reference value. , the areas of the inner light receiving element and the outer light receiving element are set, or the output of one side is multiplied by a coefficient to electrically adjust both outputs.

In this state, if the object is far from the focus position, the amount of light received by the outer light receiving element increases, and conversely, if the object is in front of the focus position, the amount of light received by the outer light receiving element decreases, so both outputs Since the difference varies with respect to the reference value, the position of the object can be detected from the amount of variation.

Additionally, if the object is tilted with respect to the optical system, there will be a difference between the output of the split light-receiving element on one side and the output of the split light-receiving element on the other side, which are divided by the axes that are orthogonal to each other. The inclination of the object can be detected from the signal corresponding to .

〔Example〕

Embodiments in which the displacement detection device of the present invention is applied to a microscope will be described below with reference to the drawings.

The first embodiment of the Natsudo-no-Ban is shown in FIGS. 1 to 6. FIG. 6 shows the schematic configuration of the microscope of this embodiment. The microscope irradiates light from a first light source 1 consisting of a halogen lamp onto an object to be measured 6 placed on a stage 5 through a condenser lens 2, a half mirror 3, and an objective lens 4. The structure is such that the reflected light is observed through a half mirror 7 and an eyepiece 8. Here, the light source 1, lenses 2, 4.8, and half mirrors 3, 7 constitute an optical system 9 of this embodiment.

A half mirror 11 is arranged on the optical axis of the objective lens 4. A second light source 13 consisting of a laser diode is arranged at a position perpendicular to the optical axis passing through the half mirror 11 via a collimating lens 12.

Further, on the optical axis of the objective lens 4, a sensor 14 and an imaging lens 15 for forming an image of the reflected light on the sensor 14 are arranged. Note that a mask 16 is arranged between the sensor 14 and the imaging lens 15.

As shown in FIG. 1, the sensor 14 includes an inner light-receiving element 21 and an outer light-receiving element 22 that are arranged concentrically about the optical axis of the objective lens 4. The inner light receiving element 21 is formed in a circular shape with a circular outer periphery. The outer light-receiving element 22 is formed into an annular shape and is composed of divided light-receiving elements 22, to 224, which are equally divided into four pieces in the circumferential direction using the X and Y axes that are perpendicular to each other as dividing lines. The output signals from these inner light receiving elements 21 and the divided light receiving elements 22 configuring the outer light receiving element 22.
The output signal from ~224 is the amplifier 23.24+~24
After being amplified via the signal processing circuit 4, the signal is supplied to the signal processing circuit 25.

The signal processing circuit 25 is connected to the inner light receiving element 2 of the sensor 14.
The displacement detection circuit 31 outputs a signal corresponding to the difference between the output signal of the outer light-receiving element 22 and the output signal of the outer light-receiving element 22. A tilt detection circuit 41 outputs a signal corresponding to the difference between the output of the side split light receiving element, that is, a signal corresponding to the inclination of the measuring object 6, and a diameter of the split light receiving elements 221 to 224 constituting the outer light receiving element 22. A region signal generation circuit 51 that outputs a region signal when the difference between the outputs of two divided light-receiving elements facing each other in the direction exceeds a predetermined value, and a region signal being output from the region signal generation circuit 51. and an AND gate 61 as an edge signal generation circuit which outputs an edge signal when the output signal from the displacement detection circuit 31 reaches a reference value.

The displacement detection circuit 31 connects each of the amplifiers 24° to 24.
The split light-receiving elements 22° to 22. a sum calculator 32 that calculates the sum of the output signals from the sum calculator 32; a multiplier 33 that multiplies the output signal of the sum calculator 32 by a coefficient α; A difference calculator 34 calculates the difference between the output signal from the light receiving element 21, and compares the output signal of this difference calculator 34 with the reference level signal of O, and when the output signal is smaller than the reference level signal, a child signal is generated. and a comparator 35 which outputs one signal when the output signal is larger than the reference level signal and outputs a matching signal when both match.

The output of the comparator 3-5 is input to a focus position adjustment device 36. The focal position adjustment device 36 includes a motor M that moves the document table 5 in the optical axis direction of the objective lens 4.
z, and a motor drive control circuit 37 that controls the drive of this motor Mz. The motor drive control circuit 37 drives the motor Mz in a direction according to the signal from the comparator 35, and stops the drive when a matching signal is applied. That is, based on the output from the displacement detection circuit 31, the measurement object 6 and the optical system 9 are moved relative to each other in the direction of the focal depth of the optical system 9, and
The inclination detection circuit 41, which stops the relative movement when the output from the displacement detection circuit 31 reaches a reference value, has a split light receiving element 22 inputted through the amplifiers 24+ and 242.
+, a sum calculator 42 that calculates the sum of the output signals from 222;
, a sum calculator 43 that calculates the sum of the output signals from the divided light receiving elements 22a and 224 inputted through the amplifiers 24a and 244, and the amplifier 24. ．． 24. A sum calculator 44 that calculates the sum of output signals from the divided light receiving elements 221, 224 inputted through the amplifiers 24□, 24. a summation unit 45 that calculates the sum of the output signals from the divided light receiving elements 22□, 223 input through the summation unit 42, 43;
A difference calculator 46 calculates the difference between the output signals of , that is, the inclination of the object to be measured 6 in the X-axis direction, and a difference between the output signals of the sum calculators 44 and 45, that is, the inclination of the object to be measured 6 in the Y-axis direction. and a difference calculator 47.

Here, the output signals from each of the difference calculators 46 and 47 are used to drive the motors Mx and My that tilt the document table 5 in the X and Y axis directions with respect to the optical axis of the objective lens 4. It is input to the control circuit 48. The motor drive control circuit 48 drives the motors Mx and My in that direction based on the output from the difference calculator 46, 47.

The area signal generation circuit 5I includes a difference calculator 52 that calculates the difference between the output signals from the divided light receiving elements 221 and 223 that are input through the amplifiers 241 and 24s, and an amplifier 24! ,
244, the divided light receiving element 22. ．． 224
A difference calculator 53 calculates the difference between the output signals from the difference calculator 53, and output signals from each difference calculator 52 and 53 are converted into a reference level signal Vr.
ef(+).

Window comparators 54 and 55 that compare with Vref(-) and output a region signal when the output signal is not within the reference level signal range, and one of the window comparators 5
4.55 and an OR gate 56 which outputs the signal to the ant gate 61 when the area signal is output.

The ANDCATE 61 constituting the edge signal generation circuit performs the following operations only when a coincidence signal is output from the comparator 35 while a region signal is being output from either of the window comparators 54 and 55 through the OR gate 56. Outputs an edge signal.

Here, the edge signal output from the AND gate 61 is input to a displacement detection device 71 that is linked to the movement of the stage 5. The displacement detection device 71 includes an encoder 72 that generates a pulse signal according to the amount of movement of the workpiece table 5, a counter 73 that counts the pulse signal output from the encoder 72, and a value of the counter 73 that is used as the edge signal. It is comprised of a latch circuit 74 that latches when .

Next, the operation of this embodiment will be explained.

First, the signal A obtained from the inner light receiving element 21 of the sensor 14 is
, ~22. Assuming that the signals obtained from are B and ~B4, the output signal S of the difference calculator 34 of the displacement detection circuit 31 becomes 5=A-α(B+ +B2 +B3 +B4). Here, as shown in FIG. 2(A), when the object to be measured 6 is located at the focal position of the objective lens 4, that is, when it is in focus, the output signal S becomes the reference value, in this case 0. , each divided light-receiving element 22, which constitutes the inner light-receiving element 21 and the outer light-receiving element 22, -22. The area of , or the coefficient α of the multiplier 33 is selected in advance.

In addition, here, the divided light receiving elements 22□ to 22. which constitute the outer light receiving element 22 are shown. The arrangement position of the sensor 14 is adjusted so that the signals B1 to B4 from the sensor 1 are equal to each other.
Align the center of 4 with the optical axis.

(Autofocus operation) Now, as shown in FIG. 2(B), if the measurement object 6 is far away from the focal position of the objective lens 4, the amount of light received by the outer light receiving element 22 increases, so the difference calculation is performed. The output signal SO from the device 34 is given to a comparator 35. Then,
A child signal from the comparator 35 is sent to the motor drive control circuit 3.
7, the direction in which the stage 5 approaches the focal position via the motor drive control circuit 37 is
is driven. As a result, when the object to be measured 6 reaches the focal position of the objective lens 4, that is, when the object is in focus,
Since the output signal S becomes 0, driving of the motor Mz is stopped. In other words, focus is automatically adjusted.

Conversely, as shown in FIG. 2(C), if the object to be measured 6 is in front of the focal position of the objective lens 4, the amount of light received by the outer light receiving element 22 decreases, so that the difference calculator 34 The output signal S>0 is given to the comparator 35. Then,
One signal from the comparator 35 is sent to the motor drive control circuit 3.
7, the motor Mz is driven via the motor drive control circuit 37 in a direction in which the stage 5 approaches the focal position. As a result, when the object to be measured 6 reaches the focal position of the objective lens 4, that is, when it is in focus, the output signal S becomes 0, and the driving of the motor Mz is stopped. In other words, focus is automatically adjusted.

(Edge Detection Operation) Now, as the stage 5 moves in the X and Y axis directions, the edges of the object to be measured 6 (for example, edges in dark areas) are moved upward (as shown in Fig. 1), as shown in Fig. 3. Let us consider the case of moving in the Y-axis direction). In this case, the signal A obtained from the inner light receiving element 21 changes as shown in FIG. 4(A). Furthermore, each divided light receiving element 22 . ~
The signal B l-84 obtained from 224 is shown in FIG.
Changes as shown in .

Then, the signals B1 to B4 obtained from these divided light receiving elements 22□ to 224 are sent to the summation unit 3 of the displacement detection circuit 31.
2, and then multiplied by a coefficient α in a multiplier 33, and then input to one input terminal of a difference calculator 34. In other words, one input terminal of the difference calculator 34 is connected to the
) is input. As a result, the difference calculator 34 calculates the difference between the signal A shown in FIG. 4(A) and the signal shown in FIG. 4(C), and outputs the difference as an output signal S.

That is, the signal shown in FIG. 4(D) is output.

In addition, the signal B obtained from the divided light receiving elements 22□, 223
l, B3 are connected to the difference calculator 52, divided light receiving elements 22t,
The signal obtained from B2.224. B4 are respectively input to the difference calculator 53. As a result, the difference calculator 52 provides the difference between the signals B+ and Bs to the window comparator 54 as an output signal G1. Further, from the difference calculator 53, a signal B2. The difference between B4 and B4 is provided to the window comparator 55 as an output signal G2.

Here, the edge 6 of the object to be measured is, for example, Y in FIG.
Since it is moving in the axial direction, the output signals Gl and G2 from the difference calculators 52 and 53 change as shown in FIGS. 4(E) and 4(F). Then, each window comparator 54,5
5 is the output signal G1 given from the difference calculators 52 and 53.
．． G2 and the reference signal V ref (+), V ref (-
), the output signal G + +G2 is the reference signal V
H-level output signals R1 and R2 are output only while exceeding ref(+) and V ref(-).

These signals R1 and R2 are applied to one input terminal of AND gate 61 through OR gate 56. Therefore, one input terminal of the ant gate 61 is connected to the input terminal shown in FIG.
A region signal R shown in G) is input.

On the other hand, the output signal S output from the difference calculator 34 is
The signal is input to the comparator 35. The comparator 35 is
When the output signal S from the difference calculator 34 crosses the reference level signal of 0, a pulse signal P shown in FIG. 4 (H') is applied to the other input terminal of the AND gate 61.

The AND gate 61 outputs an edge signal E of, for example, 10 μsec as shown in FIG. 4(I) when the signals applied to both input terminals are both at H level. As a result, the count value of the counter 73 is latched into the latch circuit 74. That is, the value of the counter 73 when the edge of the object to be measured 6 is detected is latched.

(Tilt correction operation) For example, as shown in FIG. 5, when the measurement target 6 is tilted, the amounts of light received by the divided light receiving elements 221 to 224 are different from each other, so that the measurement target 6 is determined based on the difference in the received light amounts. The slope of can be found. Therefore, by correcting the inclination, the inclination of the measurement object 6 can be corrected.

Therefore, in the tilt detection circuit 41, the summation unit 42 uses the divided light receiving elements 22. ．． Signals Bl and B obtained from 22□
The sum of 2 is divided into divided light receiving elements 223,
224, the sum of signals B3 and B4 obtained from
4, the sum of the signals Bl and B4 obtained from the divided light receiving elements 221 and 224 is calculated by the summation unit 45. , 223, the signal B2. The sum of B3 is calculated respectively.

The difference calculator 46 calculates the difference between the output signals of the sum calculators 42 and 43, and provides the difference ΔX to the motor drive control circuit 48.

Further, the difference calculator 47 calculates the difference between the output signals of the sum calculators 44 and 45, and provides the difference Δy to the motor drive control circuit 48. Thereby, the motor drive control circuit 48 drives each motor Mx, My based on the difference ΔX, Δy,
When the difference ΔX, Δy disappears, the motors Mx, My
Stops driving.

Therefore, according to this embodiment, the light from the light sources 1 and 13 is irradiated onto the measurement object 6 via the objective lens 4, and
The reflected light is received by the inner light receiving element 21 and the outer light receiving element 22 that constitute the sensor 14, and these inner light receiving elements 21
Since the displacement detection circuit 31 outputs a signal corresponding to the difference between the output of the outer light receiving element 22 and the output of the outer light receiving element 22, the position of the object to be measured 6 can be detected from the output signal. Therefore, there is no need to arrange a pair of distance-measuring objective lenses as in conventional electronic distance meters, and there is no need to attach one reflecting mirror indirectly or indirectly to the target object as in Michelson interferometers. Since it is small in size, it is possible to detect the displacement of an object without being limited by the object.

Furthermore, by using one sensor 14, the focus can be automatically adjusted and the edges of the measurement target 6 can also be detected. When the mechanism is configured separately, the structure can be simplified and the number of parts can be reduced. This not only reduces costs but also allows the device to be made more compact. Furthermore, assembly and adjustment are easy, and reliability as a device can be improved.

In particular, since the autofocus mechanism is composed of the sensor 14, the displacement detection circuit 31, and the focal position adjustment device 36, a pair of distance measuring objective lenses are placed on both sides of the projection lens, unlike a conventional projector. Since there is no need to place
The field of view is not restricted, and there is no problem in attaching and detaching the object to be measured.

In addition, since the outer light receiving element 22 is constituted by four divided light receiving elements 221 to 224, the difference between the output signals of these divided light receiving elements 22 and 224 can be determined from the difference in the output signals of the divided light receiving elements 22 and 224.
can detect the inclination of motors Mx, My
The inclination can be corrected by

Moreover, if the sensor 14 is arranged so that the output signals of the divided light receiving elements 221 to 224 are equal to each other, the center of the sensor 14 can be aligned with the optical axis. Therefore,
The attachment of the sensor 14 can be easily adjusted.

In addition, in the above embodiment, the machining/sodging of the measurement target 6 is performed in the first
Although the case where the object to be measured 6 moves in the Y-axis direction in FIG. Edges of the object 6 can be detected.

A second example is shown in FIG. 7. In the explanation of the figure, the same components as in the first embodiment are given the same reference numerals, and the explanation thereof will be omitted or simplified.

In this embodiment, the sensor 14, displacement detection circuit 31, tilt detection circuit 41, and area signal generation circuit 51 in the first embodiment are changed to a sensor 14A, displacement detection circuit 131, tilt detection circuit 141, and area signal generation circuit 151. This embodiment is the same as the first embodiment except for the following points.

The sensor 14A includes an inner light receiving element 21 and an outer light receiving element 22 that are arranged concentrically about the optical axis of the objective lens 4, as in the first embodiment. The inner light-receiving element 21 is a semicircular inner divided light-receiving element 21 that has a circular outer periphery and is equally divided into two pieces with the Y-axis as a dividing line.
1,212. Outer light receiving element 22
is formed in an annular shape, and the X-axis is the dividing line,
Outer divided light receiving element 221 equally divided into two in the circumferential direction
．． 222.

The displacement detection circuit 131 includes a sum calculator 132 that calculates the sum of output signals from the divided light receiving elements 21□ and 212 that are input through amplifiers 231 and 232, and an amplifier 241.
Divided light receiving elements 22□, 22□ input through 24□
a sum calculator 133 that calculates the sum of the output signals from the sum calculator 133, and a multiplier 1 that multiplies the output signal of the sum calculator 133 by a coefficient α.
34, the output signal of this multiplier 134 and the sum operator 1
A difference calculator 135 calculates the difference between the output signal of 32 and the output signal of 0, and compares the output signal of this difference calculator 135 with a reference level signal of 0, and when the output signal is smaller than the reference level signal, the child signal is calculated as the output signal. The comparator 136 outputs one signal when the signal is larger than the reference level signal, and outputs a match signal when the two match.

The tilt detection circuit 141 includes a difference calculator 142 that calculates the difference between the output signals from the divided light receiving elements 21□ and 21□ that are input through amplifiers 231 and 232, an amplifier 24+,
Divided light receiving elements 221 and 222 input through 24g
and a difference calculator 143 that calculates the difference between the output signals.

The area signal generation circuit 151 is connected to the slope detection circuit 14.
1 and the difference calculators 142 and 14 of this slope detection circuit 141.
The output signal from 3 is the reference level signal V ref (+)
, window comparators 152 and 153 that compare with V ref (-) and output a region signal when the output signal is not within the signal range of the reference level, and either of the window comparators 152 and 153 output a region signal. and an OR gate 154 which outputs the signal to the game 1-61.

Therefore, in this case, the signals obtained from the inner divided light receiving elements 211 and 212 of the sensor 14A are A11A2, and the signals obtained from the outer divided light receiving elements 22□ and 222 are Bl,
B2, the output signal S of the difference calculator 135 of the displacement detection circuit 131 becomes S=(A1+A2)-α(Bl + B2). Here, as shown in FIG. 2(A), when the measurement object 6 is located at the focal position of the objective lens 4,
In other words, when the focus is achieved, the output signal S is the reference value,
Here, the inner divided light receiving elements 21□, 2
12 and the outer divided light receiving elements 221 and 222, or the coefficient α of the multiplier 134 is selected in advance.

(Autofocus operation) Even in the case of this embodiment, if the measurement target 6 is far away from the focal position of the objective lens 4, the amount of light received by the outer light receiving element 22 increases, so the difference calculator 135 outputs Signal S
Conversely, if the object to be measured 6 is located in front of the focal position of the objective lens 4, the amount of light received by the outer light receiving element 22 will decrease, so the output signal S>0 from the difference calculator 135 will be ,
Each is provided to a comparator 136. Therefore, similarly to the first embodiment, the drive of the motor Mz is stopped via the motor drive control circuit 37 when the stage 5 reaches the focal position. In other words, focus is automatically adjusted.

(Tilt correction operation/edge detection operation) Output signals At from the inner divided light receiving elements 21+ and 21□,
The difference ΔX of A2 is calculated by the difference calculator 142, and the difference ΔX between the outer split light receiving elements 22. ．． Difference Δy between output signals Bl and B2 from 22□
are calculated by the difference calculator 143, so
The inclination of the measurement object 6 can be corrected based on these differences ΔX and Δy.

At the same time, since these differences ΔX and Δy are input to the window comparators 152 and 153, the edges of the measurement object 6 can be detected in the same manner as in the first embodiment.

Therefore, the second embodiment also has the advantage of being able to achieve the effects described in the first embodiment and of simplifying the signal processing circuit 25.

In addition, in the above first and second embodiments, the sensor 14.1
Only the outer light-receiving element 22 constituting 4A may have an annular shape, or both the inner light-receiving element 21 and the outer light-receiving element 22 may have an annular shape.

Further, in the first embodiment, the outer light-receiving element 22 is equally divided into four pieces, but the inner divided light-receiving element 21 may be equally divided into four pieces. At this time, the number of divisions may be four or more. Furthermore, in the second embodiment, the inner light receiving element 21
Although both the outer light receiving element 22 and the outer light receiving element 22 are equally divided into two parts, the number of divisions may be two or more.

Furthermore, in each of the above embodiments, the displacement detection circuit 31.1.
It is also possible to convert the output signals from the difference calculators 34 and 135 of 31 into digital signals and display them digitally. In this way, the distance to the current measurement site can be displayed using the focal position of the optical system 9 as a reference. In other words, displacement in the Z-axis direction can be detected. Furthermore, the difference calculators 46, 47 .
By converting the output from 142 and 143 into a digital signal and displaying it digitally, the X and Y of the measurement object 6 can be
The axial tilt can also be displayed.

Further, in each of the above embodiments, reflected light from the measurement object 6 is used, but transmitted light may also be used. Further, each of the above-mentioned embodiments is an example in which the present invention is applied to a microscope, and the present invention is not limited thereto, but can be used in general as a device for detecting displacement of an object in a non-contact manner.

For example, if this is used as a probe for a three-dimensional measuring machine, and the object to be measured and the optical system 9 are moved relative to each other so that the output signal from the displacement detection circuits 31, 131 always becomes the reference value, the probe can be moved. It is possible to perform so-called scanning measurement, in which the measurement surface of the workpiece can be moved at a fixed distance without contact.

〔Effect of the invention〕

As described above, according to the present invention, light from a light source is irradiated onto an object through a lens, and the light is received by an inner light receiving element and an outer light receiving element that constitute a sensor. Since the sensor outputs a signal corresponding to the difference between the output and the output of the outer light receiving element, the position of the object can be detected from the output signal. Therefore, there is no need to dispose a pair of distance measuring objective lenses as in a conventional electronic distance meter, and there is no need to attach one reflecting mirror indirectly or indirectly to the target object as in a Michelson interferometer. Since it is small in size, it is possible to detect the displacement of an object without being limited by the object. Also, of the inner light receiving element and the outer light receiving element, a signal corresponding to the difference between the output of the split light receiving element on one side and the output of the split light receiving element on the other side, which are divided by the axes perpendicular to each other as boundaries, is outputted. Therefore, the inclination of the object can be detected from the output signal.

[Brief explanation of the drawing]

1 to 6 are diagrams showing a first embodiment of the present invention.
The figure is a circuit diagram mainly showing the electrical configuration, Figure 2 is a diagram to explain the autofocus operation, Figure 3 is a diagram to explain the edge detection operation, and Figure 4 is the signal flow at that time. FIG. 5 is a diagram showing the state when the object to be measured is tilted, and FIG. 6 is a diagram showing the schematic configuration of the microscope. FIG. 7 is a circuit diagram showing a second embodiment of the present invention. 6...Measurement object, 9...Optical system, 14.14A.
...Sensor, 15...Imaging lens, 2I...Inner light receiving element, 2i+, 2It...Inner divided light receiving element, 22...Outer light receiving element, 22. ．． 22□, 22
3,224...Outer divided light receiving element, 31,131...
・Displacement detection circuit, 41.141...Inclination detection circuit.

Claims (2)

[Claims] (1) An optical system that includes a light source and a lens that irradiates the object with light from the light source, an inner light-receiving element with a circular outer periphery, and an annular outer light-receiving element that is arranged concentrically with the inner light-receiving element. And,
Either one of the inner light receiving element and the outer light receiving element is constituted by divided light receiving elements divided into at least four equal parts in the circumferential direction, and the sensor forms an image of the light irradiated on the object. a displacement detection circuit that outputs a signal corresponding to the difference between the output of the inner light-receiving element and the output of the outer light-receiving element of the sensor; a tilt detection circuit that outputs a signal corresponding to the difference between the output of the divided light receiving element on one side and the output of the divided light receiving element on the other side, which are divided by axes that are orthogonal to each other as boundaries; Detection device. (2) An optical system including a light source and a lens that irradiates the object with light from the light source, an inner light-receiving element with a circular outer periphery, and an annular outer light-receiving element arranged concentrically with the inner light-receiving element. And,
A sensor configured by an inner divided light receiving element and an outer light receiving element in which the inner light receiving element and the outer light receiving element are equally divided into at least two parts in the circumferential direction; an imaging lens for imaging; a displacement detection circuit that outputs a signal corresponding to the difference between the output of the inner light-receiving element and the output of the outer light-receiving element of the sensor; a tilt detection circuit that outputs a signal corresponding to the difference between the output of the divided light receiving element on one side and the output of the divided light receiving element on the other side, which are partitioned by mutually orthogonal axes passing through the center of the sensor on the same side; A displacement detection device characterized by comprising: