JPH01182702A - Method and apparatus for detecting position of movable body - Google Patents

Abstract

PURPOSE:To perform detection characterized by quick response and excellent accuracy with a single apparatus, by sending and receiving a light beam between a movable body and a fixed body, and detecting the intensity of the light and the average value and the root mean square of distances between the end part of an optoelectronic transducer and the incident position of the beam by using the optoelectronic transducer. CONSTITUTION:A light beam, which is emitted from a light source 1 from the side of a movable body 2, is inputted into an optoelectronic transducer 5 on the side of a fixed part 3. The intensity of the light beam and the average value and the root mean square of the distances between the end part of the transducer 5, which is weighted with the intensity of the light, and the incident position of the beam are detected by using the transducer 5. Primary and secondary outputs, which are proportional to the average value and the root mean square, are taken out. The incident position of the beam is detected based on the primary output in an operating part 6. The dispersion of the beam is operated and detected based on the primary and secondary outputs. The position of the movable body 2 with respect to the fixed part 3 is computed based on the result.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to precise positioning and position control of each element (movable body) in machine tools, inspection equipment, etc., or to experiments on surface plates, optical laboratory benches, etc. The present invention relates to an optical method and device for detecting the position of a movable body, which is suitable for use in precise positioning and alignment adjustment of each element (movable body) in a device.

[Prior Art] Before explaining a conventional optical movable body position detection device,
First, the conventional optical position detection device (PSD) used in the device
tiveD_tector) will be explained.

Figure 18 shows, for example, precision machinery VO1, 51, N (14, 1
985. It is a side view showing the conventional optical position detection device shown in ``Application of PSD in position measurement'' written by Osamu Kanazawa, pages 730-737.

In this conventional optical position detection device, as shown in FIG. 18, on a flat silicon substrate, a first resistor M51 made of a P-type semiconductor (photoelectric converter) that receives optical input, and this first resistive layer 51 are provided. A second resistance layer 52 made of an N-type semiconductor (photoelectric converter) is connected via a depletion layer 53, and the first resistance layer 51 is formed to have a uniform resistance value over the entire surface. There is.

In order to detect the one-dimensional position of the light beam incident on the first resistance layer 51, electrodes 54.
55 are attached to each. Further, a bias electrode 56 is connected to the center of the second resistance layer 52.

In such an optical position detection device, arrow a is shown in FIG.
As shown in , when a light beam is incident on the first resistance layer 51, its one-dimensional position can be obtained as follows. However, as for the coordinate system, the origin is the midpoint between the electrodes 54 and 55, the coordinate of the incident position with respect to this origin is X, and the right direction in FIG. 18 is the positive direction.

When a light beam is incident on the first resistance layer 51 as indicated by arrow a, electrons and holes proportional to the light energy are generated at the incident position. The generated holes flow through the first resistance layer 51, and the current value is increased from the electrodes 54 and 55 at both ends of the first resistance layer 51, respectively. t I20. Further, one generated electron flows from the depletion layer 53 to the second resistance layer 52,
It is taken out from the bias electrode 56. At this time, holes, that is, photocurrent, are distributed in inverse proportion to the distance from the incident position to the electrodes 54 and 55 due to the uniform resistance of the first resistance layer 51.

Therefore, if the total length of the first resistance layer 51 is 2Qo, then Ito/(Qo X)=IZO/(Qll+X)"
= k'' (1) is obtained, where k is a quantity that depends on the optical energy and does not depend on the incident position X.

Therefore, the current value is measured. For lI2°, (
Engineering t. - engineering2゜)/(11゜+12゜), we get (
1) From the formula, (I,.-I,0)/(I,.+I
2o)k・(Qo+x)k・(Qo−x)k・
(Q0+x)+k・(flo-x)=2 and -x/(
2-Qo)=x/Q. ...(2), and the incident position X is x=Q regardless of the optical energy.・(1,,-
I2. ) fly,. +Eng.2o) ...As (3),
Detected.

As described above, one of the light beams incident on the first resistance layer 51
The dimensional position X is the current value I□ measured by the optical position detection device. It is determined from lI2° based on equation (3). Note that the two-dimensional position of the light beam is also measured in the same manner as the principle of one-dimensional position measurement described above.

In this case, an optical position detection device as shown in FIG. 19 or 20 is used.

The optical position detection device shown in FIG. 19 is a surface-divided type.
Electrodes 57, 58 are attached to each end of the first resistive layer 51 orthogonally to the electrodes 54, 55, respectively. In such an optical position detection device, the current value detected from each of the electrodes 54 and 55 is 11 degrees.

By step 2°, the X coordinate is determined based on equation (3), and the y coordinate is determined based on the current values 11@tI4@ detected from the electrodes 57 and 58, respectively.

The optical position detection device shown in FIG. 20 is of a double-sided split type, and electrodes 57 and 58 are respectively attached to both ends of the second resistance layer 52, orthogonal to the electrodes 54 and 55.

At this time, the second resistance layer 52 is also formed to have a resistance value similar to that of the entire surface. Even in such an optical position detection device, the current value from the electrodes 54 and 55 is I. , Eng. According to
The X-coordinate is obtained, and the y-coordinate is obtained by the current value ■3°t I4° from the electrodes 57 and 58.

A conventional position detecting device for a movable body using the optical position detecting device as described above is shown in FIG. In FIG. 21, 59 is an optical position detection bag for detecting the one-dimensional position of the light beam L0 shown in FIG. is a laser light source that is fixed on the movable body 60 and irradiates the optical position detection device 59 with a light beam L0 perpendicularly.

With this configuration, the position of the light beam L6 incident on the optical position detection device 59 can be detected by the current value. .

The position of the movable body 60 in the direction of the arrow is detected by detecting the position of the movable body 60 based on the equation (3) and the equation (3).

Here, when the optical position detection device 59 shown in FIGS. Sixty two-dimensional positions are detected.

Note that in FIG. 21, the laser light source 61 is fixed on the movable body 60, but conversely, the optical position detection device 59 is fixed on the movable body 60.
0, and the laser light source 61 may be provided on the fixed part side.

In addition to the position detection device for a movable body shown in FIG. 21, there is also a conventional device as shown in FIG.
page). In FIG. 22, 61 is a laser light source that vertically irradiates the light beam L0 onto the movable body surface 63, 62 is a lens that focuses the light beam L0 from the laser light source 61, and 64I-
A lens 65 receives the scattered light S0 reflected and scattered by the AM moving object surface 63, and 65 is the scattered light S0 that has passed through the lens 64.
This is a light receiving element (the one shown in FIG. 18 may be used) for detecting the position (displacement) of the movable body surface 63 by receiving the scattered light S and detecting the incident position of the scattered light S.

The position measurement principle of such devices is triangulation,
A light beam L is irradiated onto the movable body surface 63 that is the object to be measured, and the reflected and scattered light S is sent to the light receiving element 6 through a lens 64.
5, and the position of the movable body surface 63 (position of the irradiation direction of the light beam L0) is measured by the output of this light receiving element 65.The apparatus shown here is shown in FIG. As shown, the distance X between positions A1 and Bi on the movable body surface 63
This is intended to detect the amount of displacement between 0 and the surface of the movable body 6
3 is at position A, the scattered light S01 is reflected by the light receiving element 6.
Scattered light S when the movable body surface 63 is at position B. 2 is position B2 on the light receiving element 65
incident on .

Therefore, in response to the movement of the movable body surface 63 from the position A t "" B 1, the incident position of the scattered light S0 incident on the light receiving element 65 also changes between A yaw and B2, and the light receiving By detecting the incident position of the scattered light S0 on the element 65, the displacement of the movable body surface 63, that is, the one-dimensional position of the movable body can be detected.

In this way, the device shown in FIG. 21 can detect the one-dimensional or two-dimensional position of the movable body in a plane perpendicular to the irradiation direction of the light beam L0, while the device shown in FIG. The one-dimensional position of the movable body in the irradiation direction can be detected.

[Problems to be Solved by the Invention] However, with any of the devices shown in FIGS. It is not possible to simultaneously detect the position in a plane orthogonal to the irradiation direction with one device. Therefore, in order to realize this, it is necessary to combine a plurality of devices shown in FIG. 21 or 22, which makes the device complicated and expensive.

Further, in particular, in the apparatus shown in FIG. 22, since the triangulation method is used, the optical system becomes large, making it difficult to miniaturize the apparatus.

The present invention was made in order to solve the above-mentioned problems, and detects information on the position and spread (dispersion) of a light beam, and detects information on the irradiation direction of the light beam and the direction perpendicular to the irradiation direction of the light beam. An object of the present invention is to provide a low-cost and compact method and device for detecting the position of a movable body, which can detect the position of a movable body in a plane with high accuracy and fast response using a single device.

[Means for Solving the Problem] For this reason, the method for detecting the position of a movable body of the present invention is such that a light beam irradiated from the movable body side or the fixed part side is incident on the photoelectric converter on the fixed part side or the movable body side. The light intensity of the light beam, the average value of the distance between the end of the photoelectric converter and the incident position of the light beam weighted by the light intensity, and the distance of the photoelectric converter weighted by the light intensity The root mean square value of the distance between the end and the incident position of the light beam is detected by the photoelectric converter, and the distance between the end of the photoelectric converter and the light beam is detected based on the detected light intensity and the average value. In addition to extracting the primary output proportional to the average value of the distance to the beam incident position.

After extracting a secondary output proportional to the root mean square value of the distance between the end of the photoelectric converter and the incident position of the light beam based on the detected light intensity and the root mean square value, Detect the incident position of the light beam based on the primary output, calculate and detect the dispersion of the light beam based on the primary output and secondary output, and then calculate the detected incident position and dispersion of the light beam. The present invention is characterized in that the position of the movable body with respect to the fixed part is calculated based on the above.

Further, the position detection device for a movable body of the present invention includes a light source that irradiates a light beam and a photoelectric converter that receives the light beam from the light source, each fixed to either the movable body or the fixed part, In order to detect the primary output, the photoelectric converter is separated and insulated at the same distance position according to the distance from the end of the photoelectric converter at a width direction position proportional to the same distance, and the secondary output The photoelectric converter is separated and insulated at a position in the width direction proportional to the square of the distance at the same distance according to the distance from the end of the photoelectric converter, and based on the output from the photoelectric converter, the The present invention is characterized by comprising a calculation section that calculates the incident position and dispersion of the light beam and calculates the position of the movable body with respect to the fixed part from these incident positions and dispersion.

[Function] In the method for detecting the position of a movable body of the present invention described above, a light beam from the movable body side or the fixed part side is incident on the photoelectric converter provided on the fixed part side or the movable body side, and the photoelectric converter is By using the converter to detect a primary output proportional to the average value of the distance between the end of the photoelectric converter and the incident position of the light beam, and a secondary output proportional to the root mean square value of the distance, The incident position and dispersion of the light beam can be statistically easily determined based on the primary and secondary outputs from the photoelectric converter without using expensive components such as complex signal processing circuits. It is determined by the following formula. Then, from the obtained incident position and dispersion of the light beam, the position of the movable body relative to the fixed part in a plane perpendicular to the irradiation direction of the light beam and in the same irradiation direction is calculated.
Detected.

Further, the above-described position detection device for a movable body of the present invention is used directly when carrying out the method, and in the device, a light beam irradiated from a light source is transmitted from the movable body side or the fixed part side to the fixed part. The light is incident on the photoelectric converter on the side or the movable body side. A current value outputted from the photoelectric converter that is surrounded and isolated by a linear straight line and a quadratic curve, and a current from the photoelectric converter below the quadratic curve. The average value of the distance between the end of the photoelectric converter and the incident position of the light beam, which is weighted by the light intensity, can be obtained by the sum of the values. Furthermore, the root mean square value of the distance between the end of the photoelectric converter and the incident position of the light beam weighted by the light intensity can be obtained from the current value from the photoelectric converter below the quadratic curve. It will be done. moreover,
The light intensity of the light beam is detected by the sum of the current values from the photoelectric converters separated and insulated into three parts.

The primary output is obtained by dividing the average value by the light intensity, and the secondary output is obtained by dividing the root mean square value by the light intensity. The incident position and dispersion of the light beam are calculated based on these primary outputs and secondary outputs, and from the obtained incident position and dispersion, the incident position and dispersion of the light beam are calculated in the plane perpendicular to the irradiation direction and in the same irradiation direction, respectively. The position of the movable body with respect to the fixed part is calculated and detected. These calculations are performed in the calculation section.

[Embodiments of the Invention] First, a method for detecting the position of a movable body according to the present invention and its principle will be explained.

In the method of the present invention, a light beam irradiated from a light source is incident from the movable body side or the fixed part side to the photoelectric converter on the fixed part side or the movable body side. Based on the incident position, the position of the movable body in a plane perpendicular to the light beam irradiation direction (a plane parallel to the light beam incident plane of the photoelectric converter) is detected (see Figures 4 and 9). The operation is exactly the same as that of the conventional device shown in FIG.

On the other hand, even if the light beam is highly focused,
The longer the distance it reaches, the more it spreads in proportion to that distance. In other words.

By detecting the dispersion (spreading) of the light beam that has reached the photoelectric converter, the distance between the light source of the light beam and the photoelectric converter, that is, the position of the movable body in the irradiation direction of the light beam is detected (fifth (see figure).

Therefore, by detecting the incident position (average position) and dispersion of the light beam from the light source using the photoelectric converter, the position of the movable body (in the plane orthogonal to the irradiation direction of the light beam and in the same irradiation direction) can be detected. That will happen.

Therefore, in the method of the present invention, the incident position and dispersion of the light beam are determined as follows. In other words, using a photoelectric converter that outputs a predetermined current by photoelectric conversion according to the intensity of the received light beam, the light beam is irradiated from the movable body side or the fixed part side, and is directed to the photoelectric converter on the fixed part side or the movable body side. Make it incident. Then, with this photoelectric converter, first, light intensity (total intensity) //'(x)dx(=It:
Here, ρ is the light beam intensity distribution) and the average value fx・ρ of the light beam position ff1x weighted by the light intensity
(x) d x and the position of the light beam also weighted by the light intensity [root mean square value of x/,! -Detect ρ(x)dx as a current value.

Then, from the detected current value, the primary output proportional to the average distance (center of gravity position) X between the end of the photoelectric converter and the position of the light beam is calculated as K1°... /
In addition to obtaining fρ(x)dx, K, a ・/ ／ ／
After obtaining P(x)dx (where K1° and 2° are constants), based on these outputs, the order of the light beam! 11(
Center of gravity)X, x=fx・pcx)dxlfpcx)dx −(4
), and the dispersion σ2 of the light beam is detected as a
” = f x” ・i”(x)di/ / /'(
x) dx-[/ x-F(x) dx/ / /'(x)
dxl"-11-2-1-X... (5) is used for detection.

Based on the average position i and variance σ2 thus detected, the position of the movable body is calculated and detected from the relationships shown in FIGS. 4, 9, and 5, as described above.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of a movable body position detection device applied to the method of the present invention will be described below with reference to the drawings.

1 to 7 show a position detection device for a movable body as a first embodiment of the present invention, FIG. 1(a) is its overall configuration diagram, and FIG. 1(b) is a photoelectric converter thereof. DIP sensor [D: deviation, ■: 1nta
Fig. 1 (Q) is a side view of the DIP sensor, and Fig. 2 is a graph showing an example of the intensity distribution of the light beam incident on the DIP sensor. , Figure 3(a),(b)
4 is a graph showing the relationship between the detected current value obtained by the DIP sensor and the position on the DIP sensor, FIG. 4 is a graph showing the relationship between the position of the X-axis stage and the incident position of the light beam, and FIG. The figure is a graph showing the relationship between the position of the Y-axis stage and the dispersion of the light beam, Figure 6 is an overall configuration diagram showing a variation of the arrangement of the device of this embodiment, and Figures 7 (a) to (d)
2A and 2B are diagrams showing modified examples of the light source.

In the first embodiment, when detecting the two-dimensional position of the movable body,
In other words, a case will be described in which the position 1if (X, Y) of the movable body relative to the fixed portion of the axis (X-axis) perpendicular to the irradiation direction of the light beam and the axis (Y-axis) in the same irradiation direction is detected.

In FIG. 1(a), 1 indicates the light beam L as DI, which will be described later.
Laser light source (semiconductor laser) that irradiates vertically to the P sensor
, 2 is a movable body having two degrees of freedom in the X and Y directions, and is composed of an X-axis stage 2a and a Y-axis stage 2b, and is equipped with a drive mechanism (not shown). And Y-axis stage 2
A laser light source 1 is fixed on b. Further, 3 is a fixed part, and 5 is a DIP sensor as a photoelectric converter that receives the light beam L from the laser light source 1, and is fixed on the fixed part 3. Furthermore, 6 is a calculation unit that calculates the incident position (average position) i and variance σ2 based on the detection signal (1111!113) from the DIP sensor 5, and calculates the average position lx
and the position of the movable body 2 (laser light source 1) from the dispersion σ2 (
x, y).

In addition, the DIP sensor 5 of this embodiment is shown in FIG. 1(b), (
As shown in Q), two layers 5-1. It is configured as a photodiode consisting of an i-layer 5-2 and an 0-layer 5-3, and when it receives a light beam L, it outputs a predetermined current by photoelectric conversion according to the intensity of the light beam L. And each layer 5-1 to 5-
3 is a linear straight line with y=(w/Q)・x and y=(w/
Q2)・Three photoelectric conversion surfaces 5a due to the parabola X2
, 5b.

5c, and each photoelectric conversion surface 5a.

A current value of 11*12913 is detected from each of 5b and 5c.

In addition, in FIG. 1(b), the second layer 5-1 in FIG.
) with the lower left corner of the center as the origin, the X-axis goes to the right, and the Y-axis goes up (different from the X and Y axes in Figure 1(a)).
Moreover, Q and w in FIG. 1(b) are the external dimensions, that is, the length, of the DIP sensor 5, respectively.

It shows the width.

Since the movable body position detection device according to the first embodiment of the present invention is configured as described above, when detecting the position of the movable body 2 (that is, the position of the laser light source 1), first the movable body 2 from the laser light source 1 on the Y-axis stage 2b to the fixed part 3
A light beam L is irradiated onto the upper DIP sensor 5. In this way, the DIP sensor 5 receiving the light beam L performs photoelectric conversion according to the intensity of the light and generates a current. The detection signal 13 obtained from the DIP sensor 5 through this photoelectric conversion is input to the calculation section 6.

Thereafter, the DIP sensor 5 and the calculation unit 6 calculate the average position (center of gravity) Y1 dispersion (spread) σ2 of the light beam L as follows, and further.

From these calculation results, the digit [(X, Y) of the movable body 2 is calculated and detected.

Now, assume that a light beam L having a one-dimensional Gaussian intensity distribution ρ(s) as shown in FIG. 2 is incident on the DIP sensor 5. Here, the average position of the Gaussian distribution above! ,
The variance is σ2. The maximum intensity is Imax, and the total intensity (area of the shaded area in FIG. 2) is It. In addition, Figure 1 (
It is assumed that the light intensity distribution is constant in the y direction in b).

At this time, there is a relationship between position [x and the sum of detected current values 11 and 12 as shown in FIG. There is a relationship as shown in FIG. 3(b). Therefore, let the photoelectric conversion efficiency of the photodiode that is the DIP sensor 5 be K, and for simplicity,
B, =vr/Q, a2=w/Q2, the detected current value 1zylz+i3 is i,=to/'p(x)・a,x
”dx・−(6)L=K−fip(x
) (a, x - a, x'') dx ・= (7) i, = 1, /'ρ(x)・a, (u-x) dx ''' (U
From these equations (6) to (8), iz+iz+
i,=ni/,'ρ(x)・a,1)dx"K"w-/
, 'ρ(x)dx = -w-It ... (9) i, +i, = -7, 'ρ(x)・a, xdx -
(10) is obtained. Here, equation (9), i.e. i1+i
2+i.

The quantity related to the total intensity It of the light beam L is detected by the equation (10), that is, i1+i.
A quantity related to the average value of the coordinate X weighted by the intensity of the light beam L is detected, and the root mean square value of the coordinate X weighted by the intensity of the light beam L is detected by (6) 2, that is, 11.

Therefore, from equations (4), (9), and (10).

is obtained, and this (xz + 12)l(ll + iz
+13), a primary output proportional to the average value X of the distance X between the end of the DIP sensor 5 and the position of the light beam L is extracted.

Furthermore, from equations (9) and (6), =□ ... (12) is obtained, and this z 1/ Cx 1 + x 2 +
x 3).

The root mean square value of the distance X between the end of the DIP sensor 5 and the position of the light beam L? A secondary output proportional to is extracted.

From the above results, in this example, the total intensity It of the light beam L is determined by equation (9) as It=(i, +i, +ia)/(K-w) −(13
), and according to equation (11), the average position i of the light beam L is x = 1(i + iz)/(it + i, + i,)
...(14), and furthermore, (5), (1
Based on equations 1) and (12), the variance σ is calculated by equation (15) below.
2 is obtained.

(15) Since there is a proportional relationship between the incident position of the light beam L on the DIP sensor 5 and the coordinate X of the X-axis stage 2a as shown in Fig. 4, Average position determined by equation (14)! Based on this, the position aX of the movable body 2 (laser light source 1) with respect to the X axis orthogonal to the irradiation direction of the light beam L is calculated and detected.

In addition, as described above, as the distance (Y) of the light beam L from the laser light source 1 to the DIP sensor 5 becomes longer, the light beam L spreads in proportion to the distance, so the DIP sensor There is a proportional relationship as shown in FIG. 5 between the dispersion σ2 of the light beam L that has arrived at 2 and the coordinate Y of the Y-axis stage 2b. Therefore, (15)
Based on the dispersion σ2 obtained by the formula, the movable body 2 (laser light source 1
) coordinate Y is calculated and detected.

As described above, according to the device of the first embodiment of the present invention, the detected current value from the DIP sensor 5 can be detected using a device with an extremely simple structure without performing complicated signal processing.
By simply performing calculations based on '1m, the primary output and secondary output for the light beam L can be obtained, and the average position i and dispersion σ2 of the light beam L can be calculated from these outputs. Based on the mean position 1tx and dispersion σ2 obtained in this way, the two-dimensional coordinate position (x , y) can be detected with high accuracy and fast response using a single device, and the device can be made smaller and lower in price.

In addition, in the first embodiment, the Y-axis table 2 of the movable body 2
Laser light sources 1 and D are placed on b and fixed part 3, respectively.
Although the IP sensor 5 is fixed, as shown in FIG.
Conversely, the DIP sensor 5 is placed on the Y-axis table 2b of the movable body 2.
may be fixed, and the laser light source 1 may be fixed on the fixed part 3.

In this case as well, the same effects as in the first embodiment can be obtained.

Further, in the first embodiment, the laser light source 1 made of a semiconductor laser is used as the light source, but the light source is not limited to a laser light source as long as it is a diverging light or a convergent light.
As shown in FIG. 7(a).

A light source that uses an incandescent lamp 4 and a pinhole 7, and uses the light from the incandescent lamp 4 that has passed through the pinhole 7 as a light beam L; ■As shown in FIG. 7(b), a light source that emits diverging light from an optical fiber 8; As shown in FIG. 7(0), an incandescent lamp 4 and a condensing lens 9 are used to convert the light from the incandescent lamp 4 focused by the condensing lens 9 into a light beam L.
A light source that uses an optical fiber 8 and a condensing lens 9 as shown in FIG.
Various types of light sources can be used, and the same effects as in the first embodiment can be obtained using any of the light sources.

Next, a movable body position detection device as a second embodiment of the present invention will be explained with reference to FIGS. 8 and 9. FIG. 8(a)
8(b) is a plan view of the DIP sensor used in this embodiment, and FIG. 9 is a graph showing the relationship between the position of the Z-axis stage and the incident position of the light beam. Note that in the drawings, the same reference numerals as those already described indicate the same parts, so the explanation will be omitted. Also, Fig. 8(a)
In the figure, the calculation unit 6 is omitted from illustration.

While the first embodiment was for detecting the two-dimensional position of the movable body 2, the second embodiment is for detecting the three-dimensional position of the movable body 2, that is, in the irradiation direction of the light beam L. The position of the movable body 2A (laser light source 1) relative to the fixed part 3 in orthogonal planes (X, Z coordinates corresponding to the x, y coordinates in the DIP sensor) and the axis (Y axis) in the same irradiation direction. The case of detecting 1iW(X, Y) will be explained.

In FIG. 8(a), 2A is a movable body having three degrees of freedom, and is composed of an X-axis stage 2a, a Y-axis stage 2b, and a Z-axis stage 2c. Also.

50 is a DIP sensor 50 provided on the fixed part 3, and this DIP sensor 50 has an eighth It is configured as shown in Figure (b).

In this embodiment, the laser light source 1 is fixed on the two-axis table 2c.

Then, as shown in FIG. 8(b), the DIP sensor 50
The sensor has n photodiodes configured similarly to the DIP sensor 5 shown in FIGS. 1(b) and 1(Q), and is arranged in a plane from 5-1 to 5-n in the y direction. ing. Note that the width Δ of each photodiode 5-1 to 5-n
W is sufficiently smaller than the movement width of the movable body 2A (laser light source 1) in the Z-axis direction.

With the above-described configuration, the current value i detected by each photodiode 5-1 to 5-n also in the device of this second embodiment.
Based on ts xz # 13, each photodiode 5-
The total intensity It, the incident position D, and the dispersion σ2 of the light beam L at 1 to 5-n are (13), (14).

It is determined by equation (15). Then, the y-direction positions of the photodiodes 5-1 to 5-n with the largest total intensity It are detected as the y-direction incident position y of the light beam L on the DIP sensor 5o.

Here, since there is a proportional relationship between the incident position y of the light beam L on the DIP sensor 5 and the coordinate Z of the Z-axis stage 2C as shown in FIG. Based on the position (incidence position) y, the coordinate Z of the movable body 2A (laser light source 1) about the Z axis that is orthogonal to the irradiation direction (Y axis) of the light beam L and also orthogonal to the X axis is calculated and detected. .

In addition, as in the first embodiment, from the incident position lx and dispersion σ2 obtained from equations (14) and (15) based on the detected current value i, 12°i, from the photodiode at the incident position y. Based on the relationships shown in FIGS. 4 and 5, the coordinate position (x, y) of the movable body 2A between an axis perpendicular to the irradiation direction of the light beam L and an axis parallel to the irradiation direction is calculated.
Detected.

In this way, according to the second embodiment of the present invention, in addition to obtaining the same effects as the first embodiment, the three-dimensional position (x, y, z ) can also be detected.

In addition, in the second embodiment, the Z-axis stage 2c is
Even if the IP sensor 50 is arranged and the laser light source 1 is arranged on the fixed part 3, the same effect as described above can be obtained. Further, as in the first embodiment, instead of the laser light source 1, the laser light source 1 shown in FIG.
) to (d) may be used.

By the way, the DIP sensor 5 used in the first and second embodiments is shown in FIG. 1(b), (Q) (or FIG. 8(b)).
1(b), (c) (
or the DIP sensor 5 (or 5
0), various other types can be used. Below, examples of photoelectric converters (DIP sensors) that can be used to carry out the method of the present invention will be described in items (1) to (2).

Figures 10(a) and 10(b) show a first modification of the DIP sensor, with Figure 10(a) being a side view and Figure 10(a) showing a first modification of the DIP sensor.
b) is a plan view thereof, and FIG. 11 is a perspective view showing an example in which the DIP sensor of the first modification is extended to a two-dimensional case.

In the DIP sensor 5A of the first modification, FIG. 10(a),
As shown in (b), a first resistance layer 11 made of a P-type semiconductor receives the light beam L, and a second resistance layer made of an N-type semiconductor connected to the first resistance layer 11 via a depletion layer 13. 12, and the first resistance layer 11 is formed to have a uniform resistance value (resistance line density re) over the entire surface.

Further, the electrodes 14 and 15 are connected to the first electrodes with an interval Q between them.
Electrodes 16 and 17 are attached to both ends of the resistive layer 11 and also to both ends of the second resistive layer 12 so as to face the electrodes 14 and 15, respectively.

Note that here, the position of the electrodes 14, 16 is taken as the origin, and the X axis is taken in the direction from these electrodes 14, 16 to the electrodes 15, 17.

Furthermore, the second resistance layer 12 has electrodes 16 at its ends.
It is formed to have a resistance value that depends on the distance from the position, and has a resistance line density r as follows: r = (re/Q) x x = (16).

Note that when a photocurrent occurs in the DIP sensor 5A,
The current values flowing through the electrodes 14, 15, 16, and 17 are i, respectively. , iyo. It is now detected as e Jzy Jz.

In addition, Ql, w, and h in FIGS. 10(a) and (b) are the external dimensions of the DIP sensor 5A, that is, the length, width, and
Show height.

In the IP sensor 5A as described above, the total intensity It, the average position x, and the dispersion σ2 of the light beam L incident on the first resistance layer 11 are obtained as follows.

Now, suppose that a light beam L having the same intensity distribution ρ(x) as in FIG. 2 is incident on FIG. :c] generates holes di and electrons dj by photoelectric conversion. That is, di=−p(x)dx=−dj=117) where K is the photoelectric conversion efficiency.

Then, the holes di move along the first resistance layer 11,
The electrons dj (=-di) reach the second resistance layer 12 from the depletion layer 13 and move along the second resistance layer 12. Since the first resistance layer 11 has a uniform resistance line density r0 over the entire surface, the holes di have the total resistance from 0 to X and the resistance from X to Ω.
are inversely proportional to the total resistance up to, respectively, dill,
di,. It is then taken out from the electrodes 14 and 15. Therefore.

di=di,. +di,. −・・・
(18) Roll becomes g.

Also, the current values 11°t and 12° taken out from the electrodes 14 and 15 are i. = f di,. ...(21)12゜=
/di,. ...(22), and what is actually measured is these current values of 18°t and 12°. 1
2° is from equations (22), (20), and (17).

i3゜== / di2゜=(1/L)・/xdi=(
K/J)・/;,'x・ρ(x)dx−(23), and the coordinate X weighted by the intensity of the light beam L
The average value of is detected by the current value of 12°.

However, the current value of 12° also depends on the intensity of the light beam L. Therefore, the total current value (it. +12°) is expressed as (21)
.

(22), (19), (20), (17)
If you find it using the formula.

il,+i,. =f(dil.+di,.)=7di=
K-1,”p (x)di = K・I t −(2
4), a quantity related to the total intensity It of the light beam L is obtained, and 11o+Lo Q is obtained from equations (23), (24), and (9). In the end, a primary output proportional to the average value i of the distance X between the position of the electrode 14 (the end of the photoelectric converter) and the position of the light beam L is obtained by 1211/(1.+120), and ( −I″t can be obtained as the intensity information of the light beam L by i, +1za).

Next, since the second resistance layer 12 has a resistance line density r as shown in equation (16), the electron dj has a total resistance R1 (X) from O to X and a total resistance R2 from X to Q. (X)
and are taken out from electrodes 16 and 17 as djt+dJa, respectively. Therefore, R1(X)=
f: rdx = roa x”/(2(1)...(
26) Rz(X)=/'rdx=ro(R"-x")/(212)...(27
), and for the total resistance R, R= f”rdx = r, II Q/2 −
(28).

dj=djt+djz...(
29).

In addition, the current values Jz*jz taken out from the electrodes 16 and 17 are as follows: J 1=/d jl (32) J 2= /
d jz (33), and what is actually measured is these current values J1? It is jl. jl
From equations (33), (31), and (12), 1, L
=/d, L=(1/Q”)・/x2dj= (K/N
").f:x"ρ(x)dx - (34), and the root mean square value of the coordinate X weighted by the intensity of the light beam L is detected from the current value j2.

However, the current value j2 also depends on the intensity of the light beam L. Therefore, the total current value (j1+j2) is (32).

(33), (30), (31), (17)
Using the formula, j + jz = / (dj + djz
)=/dj=-to-f'p(x)dx=-to-It-
= (35), and the quantity related to the total intensity It of the light beam L is obtained, and from equations (34) and (35), j + jz Q'' is obtained. In the end, by jz/(j□+ja).

2-blowout car x proportional to the root mean square value 7 of the distance
2/Q2 can be extracted.

Therefore, the dispersion (spread) σ2 of the light beam L is (25)
.

(36), From formula (5), It can be found by

From the above results, by connecting this DIP sensor 5A to the calculation unit 6, the detected current value is 11°. ,j□.

From jl, (24) (or (35)), (25
) and (37), the light beam L
The total intensity It, the average position De, and the variance σ2 can be obtained, and the DIP sensor 5A shown in FIGS. 10(a) and (b)
Also, the same effects as in the first embodiment can be obtained.

Note that the second resistance layer 12 has a resistance line density proportional to the distance.
can be realized by changing the doping amount of impurities, and also by changing the thickness of the second resistive layer 1 in inverse proportion to the distance.
2 (resistance linear density o
e1/film thickness ψ distance).

Furthermore, the IP sensor 5A as shown in FIGS. 10(a) and (b) can be expanded to an IP sensor 50A as shown in FIG. 11, which can two-dimensionally detect the incident position of the light beam L. can. In other words, as shown in FIG.
In a configuration substantially similar to that shown in FIGS. (a) and (b), electrodes 14a and 15 are
a are attached to both ends of the first resistor M11 in the y-axis direction at appropriate intervals, and the second resistor layer 1
2, electrodes 16a and 17a are connected to the electrode 14, respectively.
a, 15a. The second resistance layer 12 is formed to have an appropriate resistance line density that linearly increases along the Xyy axis direction.

Therefore, the incident position of the light beam L in the X-axis direction is determined by the detected current value from the electrodes 14 and 15. is determined and the electrode 16.1
7 is obtained from the detected current value from 7, as in the case of the DIP sensor 5A, and the dispersion σx2 in the X-axis direction is obtained by equation (37).

Further, based on the detected current values from the electrodes 14a and 15a, the incident position y of the light beam L in the y-axis direction is determined by equation (25), and 〒1° is determined from the detected current values from the electrodes 16a and 17a. Again, the dispersion σv2 in the y-axis direction is determined by equation (37).

In this way, even in two dimensions, the incident position (x, y) and dispersion (σx2.σv2) of the light beam L can be determined. , the DIP sensor 50A can also provide the same effects as those of the second embodiment.

Child! Main variable board FIG. 12 is a perspective view showing a second modified example of the DIP sensor, and the second modified DIP sensor 5B has almost the same configuration as the first modified example, as shown in FIG. , a first resistance layer 11a made of a P-type semiconductor that receives the light beam L, and a second resistance layer 12a made of an N-type semiconductor connected to the first resistance layer 11a via a depletion layer 13. 2 resistors ifJ 12 a are connected to the bias electrode 18 . Further, the first resistance layer 11a is divided into a plurality of strip-shaped (tangular) resistance layer portions 11b, llc.

The band-shaped resistance layer portions 11b and lie are arranged alternately, and the band-shaped resistance layer portions 11b located at odd-numbered positions (every predetermined position) are formed to have a uniform resistance value over the entire surface, and the even-numbered ( The band-shaped resistance layer portions 11c located at positions other than the above-mentioned predetermined positions increase linearly in the X-axis direction (1
6) It is formed to have a resistance line density r similar to Equation 6).

Furthermore, electrodes 14 are provided at both ends of each strip-shaped resistance layer portion 11b.
b, 15b are attached, and electrodes 16b, 17b are attached to both ends of each strip-shaped resistance layer portion 11c, and these electrodes 14b, 15b, 16b, 1
Current value detected from 7b 1. . t'lz. t jut
From Ja, in the same manner as in the first modification (DIP sensor 5A), the primary output and the secondary output are obtained, and the average position X of the light intensity is obtained.

Detection of the intensity It and the variance σ3 is performed. Therefore,
By connecting this DIP sensor 5B&' calculation unit 6,
This DIP sensor 5B also provides the same effects as those of the first embodiment.

Figures 13 and 14 show a third modified example of the DIP sensor. It is a top view showing the shape of.

In the DIP sensor 5C of the third modification, as shown in FIG. 1 to 19-3 are two-layer 19
It is composed of a layer A, an i layer 19b, and an n layer 19c, and when it receives a light beam L, it outputs a predetermined current by photoelectric conversion according to the intensity of the light beam L. A transparent conductive film 20 is attached to the upper and lower surfaces of each of the photodiodes 19-1 to 19-3, and the detected current value I from each of the photodiodes 19-1 to 19-3 is transmitted through the transparent conductive film 20. ,,I□,I2
is now available. Furthermore, each photodiode 19-1 to 1 has a transparent conductive film 20 attached to its upper and lower surfaces.
9-3 is placed on the glass substrate 21.

The surface of the J photodiode 19-2 on the light beam L side is covered by a first light-shielding mask 22a having the shape shown in FIG. The surface of the photodiode 19-3 on the light beam L side is covered by a second light-shielding mask 22b having the shape shown in FIG. 14(b) via an insulating protective film 23 having a light-transmitting property.

In other words, what is the boundary line between the light-shielding part by the first light-shielding mask 22a and the light-receiving part of the photodiode 19-2? =(w
/Q)*X, and the photodiode 19-2 is exposed by the light-shielding mask 22a by a width (w/Q)*X proportional to the first position @X. Similarly, the boundary line between the light-shielding part by the second light-shielding mask 22b and the light-receiving part of the photodiode 19-3 becomes a parabola of y=(w/Q2)·x2, and the photodiode 19-3 Therefore, the distance
, a width (w/Ω2)·x2 proportional to the square of the same X is exposed. Note that the x-y coordinate system is the same as that shown in FIG. 1(b).

The photodiodes 19-2, 19-3 and the photodiodes 19-1 whose upper surfaces are covered by the light-shielding masks 22a and 22b as described above are 19-1, 19-2.
They are stacked in the order of 19-3 with a light-transmitting adhesive layer 24 interposed therebetween.

In such a -DIP sensor 5C, the light beam L having the same intensity distribution ρ(X) as shown in FIG.
If the incident occurs as shown by arrow A in Figure 3, Figure 1 (b)
, the total intensity It, the average position X, and the dispersion σ2 of the light beam L are obtained in the same way as the DIP sensor 5 shown in (c).

In other words, in this DIP sensor 5C as well, there is a relationship between the position X and the detected current value 11 (=i + xa) as shown in FIG.
=11), there is a relationship as shown in FIG. 3(b).

Therefore, the current value detected by the photodiode 19-1 whose light-receiving surface is not covered at all. is,I,=KI,
−Do p (x) d z = Ko ・It −(
38), and this current value is calculated. gives a quantity relating to the total intensity It of the light beam L. In addition, the current value ■□ detected by the photodiode 19-2 covered by the light-shielding mask 22a is as follows: 11=K,・a,・/'x・p(x)dx−(3
9), and the average value of the coordinates X weighted by the intensity of the light beam L is detected by the current value calculator. Similarly, the current value I2 detected by the photodiode 19-3 covered by the light-shielding mask 22b is I2=2・az・f:x2・ρ(x)dx '−□
(40), and the root mean square value of the coordinate x weighted by the intensity of the light beam L is detected by the current value detector 2. Here, Ko=Kx−K2 is the photoelectric conversion efficiency of each of the photodiodes 19-1 to 19-3.

Therefore, from (38) and (39), 11/Io=(
Kt/Ko)"at'5F-(41) is obtained,
By this I L / I O, photodiode 1
Average value i of the distance X between the end of 9-2 and the position of the light beam L
A primary output proportional to is extracted.

Also, from 1, (38) and (41), L/Io=(
K2/x, )-a2-x""" (42) is obtained,
This L/I. As a result, a secondary output proportional to the root mean square value 7 of the distance X between the end of the photodiode 19-3 and the position of the light beam L is extracted.

Note that in reality, the light beam L is connected to the photodiode 19-
1 to 19-3, the amount of light is gradually absorbed and attenuated, so when calculating the above equations (39) to (42), it is necessary to calculate the attenuation rate in advance and take it into consideration. here.

For the sake of simplicity, the explanation is given on the assumption that attenuation of the light beam L does not occur.

From the above results, in the DIP sensor 5C, the total intensity It of the light beam L is obtained from equation (38), the average value fifx of the light beam L is obtained from equation (41), and furthermore, (41),
Based on the equation (42), the variance σ2 is obtained by the following equation (43).

Therefore, by connecting this DIP sensor 5C to the calculation section 6, the same effects as in the first embodiment can be obtained with this DIP sensor 5C.

Figures 15 (a) and 15 (b) show a fourth modification of the DIP sensor, and Figure 15 (a) is a plan view thereof, and Figure 15 (
b) is a side view thereof.

In the DIP sensor 5D of the fourth modification, FIG. 15(a),
As shown in (b), a photodiode 27 as a photoelectric converter is placed on a glass substrate 30,
The surface of the photodiode 27 on the light beam L side is provided with a first light-shielding mask 28 having the same shape as that shown in FIG. 14(a),
It is covered by a second light-shielding mask 29 having the same shape as that shown in FIG. 14(b), and both of these light-shielding masks 28 and 29 are configured as liquid crystal shutters.

In other words, both light shielding masks 28 and 29 are off (open).
In this case, the light beam L enters the photodiode 27 without being blocked at all, and the current value of the photodiode 27 corresponds to equation (38). is detected. Further, when the light-shielding mask 28 is turned on (closed) by the application of a driving voltage, a current value corresponding to equation (39) is detected, and further, when the light-shielding mask 29 is turned on by the application of the driving voltage, The current value 2 corresponding to equation (4o) is detected. This allows the operation of turning off both the light-shielding masks 28 and 29, turning on only the light-shielding mask 28, and turning on the light-shielding mask 29 at a predetermined timing. This is done repeatedly by controlling the application of the drive voltage, and the current value is calculated by time resolution. By detecting and combining ,I,,I,-t, the total intensity It of the light beam L is given by equation (38).
(41) The average position of the light beam L! But (43)
The equation gives the variance σ2.

Therefore, by connecting this DIP sensor 5D to the calculation section 6, the same effects as in the first embodiment can be obtained with this DIP sensor 5D.

In addition to the liquid crystal, an electro-optic crystal such as PLZT (lead lanthanum zirconate titanate) or KDP (potassium dihydrogen phosphate) may be used as the shutter. Further, the shape of the second light-shielding mask 29 is the same as that shown in FIG. 14(b), but this second light-shielding mask 29 is
It is also possible to use only the part surrounded by the primary straight line and the secondary blood line in Fig. 5(a). In this case, when detecting the current value 2 corresponding to equation (40), the first shading mask 28
and the second light-shielding mask 29 may both be in the on (closed) state.

Figures 16 and 17 show the fifth modification of the DIP sensor. Figure 16 is a side view, and Figures 17 (a) and (b) are the first-order characteristic ND filter and 2 is a graph showing the properties of light transmittance of a ND filter with secondary characteristics.

In the DIP sensor 5E of the fifth modification, as shown in FIG. 16, three sets of photomultiples 35 to 37 are provided as photoelectric converters, each having a length Ω. Here, a photomultiplier tube is a photomultiplier tube that increases the number of electrons mathematically when it receives light to obtain an output corresponding to the light intensity, and is particularly used for photoelectric conversion of weak light.

The surface of the photomultiple 36 on the input side of the light beam L is 1
First-order characteristic ND filter 38 as a second-order characteristic optical filter
At the same time, the light beam L of the photomultiplier 37
The input side surface is covered by a secondary characteristic ND filter 39 as a secondary characteristic optical filter. Here, the primary characteristic ND filter 38 is as shown in FIG. 17(a).
On the other hand, the second-order characteristic ND filter 39 has a transmittance X proportional to the distance X from the end of the photomultiplex 36.

As shown in FIG. 17(b), it has a transmittance b2·x2 proportional to the square of the distance X from the end of the photomultiplex 37. Note that the ND filter is NeutralDe
nsity F 1lter, which does not depend on wavelength (color), that is, has a flat 1-minute spectral transmittance.

Furthermore, the incident light beam L is transmitted through a half mirror 40,
41, the light beams are divided so as to be incident perpendicularly to the light receiving surfaces of the photomultiples 35 to 37, respectively.

In this DIP sensor 5E, when a light beam L having a light intensity distribution ρ(X) similar to that shown in FIG.
The output v0 obtained by 5 is V, = 1/'ρ(x)
dx = K・It...(44),
The quantity related to the total intensity It of the light beam L can be obtained from this equation (44). In addition, the output v1 obtained from the photomultiplex 36 covered by the first-order characteristic ND filter 38 is 1, V, = 1/'ρ(x)・b,・xdx'' (45
), and the average value of the coordinates X weighted by the intensity of the light beam L is obtained by the output VU. Similarly, the output v2 obtained by the photomultiplex 37 covered by the secondary characteristic ND filter 39 is:

Vz=ni/'ρ(x)・b2・x”dx ---(
4s), and the root mean square value of 4fjIK weighted by the intensity of the light beam L is obtained from the output v2. Here, is the photoelectric conversion efficiency.

Therefore, from equations (44) and (45), V1/Vo=b
1・x”・(47) is obtained, and this v
A primary output proportional to the average value X of the distance X between the end of the photomultiplex 36 and the position of the light beam L is extracted by z/vo.

Also, from equations (44) and (46), V, / v, :2 b2・x” ”・(4
8) is obtained, and with this V, /V0, the photomultiplier 3
A quadratic output proportional to the root mean square value P of the distance 1Iix between the end of the light beam L and the position of the light beam L is extracted.

Here, the right side of equation (45) is multiplied by 2 because
This is because the amount of light is divided into two by the half mirrors 40 and 41.

From the above results, the total intensity It of the light beam L can be obtained from equation (44), the average position of the light beam L can be obtained from equation (47), and based on equations (47) and (48), the following equation (49
) gives the variance σ2.

Therefore, by connecting this DIP sensor 5E to the calculation unit 6, the same effects as in the first embodiment can be obtained with this DIP sensor 5E.

Above, the modification of the DIP sensor has been explained, but the first
The method of the present invention can be carried out by using any of the sensors 5A to 5E in place of the DIP sensor 5 shown in FIG. In addition, the same effects as in the second embodiment can be obtained by using a sensor 50A shown in FIG. 11 in place of the DIP sensor 50 shown in FIG. 8(a).

In addition, as an application example of the movable body position detection device according to the present invention, the above-described device can also be used as a vibration meter for detecting the vibration state of the movable body 2 (or 2A). The configuration of the optical system is the same as in the embodiment described above, and includes a laser light source 1 or a DIP sensor 5 (or 5A to 5E, 50, 50A).
It is also possible to detect the vibration of the movable body 2 by interlocking one of them with the movable body 2 (fixing it completely to the movable body 2).

[Effects of the Invention] As detailed above, according to the method and apparatus for detecting the position of a movable body of the present invention, calculations can be performed based on the detected current value from the photoelectric converter without performing complicated signal processing. By simply performing position in the plane orthogonal to the same irradiation direction)
can be measured with high accuracy and fast response using a single device, and the device can also be made smaller and lower in price.

[Brief explanation of the drawing]

1 to 7 show a position detection device for a movable body as a first embodiment of the present invention, FIG. 1(a) is its overall configuration diagram, and FIG. 1(b) is a photoelectric converter thereof. Figure 1 (Q) is a side view of the DIP sensor;
FIG. 2 is a graph showing an example of the intensity distribution of the light beam incident on the DIP sensor, and FIGS. 3(a) and 3(b) show the detected current value obtained by the DIP sensor and the Figure 4 is a graph showing the relationship between the position of the X-axis stage and the incident position of the light beam, and Figure 5 is a graph showing the relationship between the position of the Y-axis stage and the dispersion of the light beam. , FIG. 6 is an overall configuration diagram showing a modified example of the arrangement of the apparatus of this embodiment, FIGS. 7(a) to (d) are all diagrams showing modified examples of the light source, and FIG. the second of
FIG. 8(a) is a diagram showing the overall configuration of a movable body position detection device as an example, FIG. 8(b) is a plan view of a DIP sensor as a photoelectric converter, and FIG. FIG. 10.11 is a graph showing the relationship between the position of the Z-axis stage and the incident position of the light beam, and FIG. 10.11 shows the first modification of the DIP sensor, and FIG. FIG. 10(b) is a plan view thereof, FIG. 11 is a perspective view showing an example in which the DIP sensor of this modification is extended to a two-dimensional case, and FIG. 12 is a perspective view showing a second modification of the DIP sensor. Figure, 1st
Figure 3.14 shows the third modification of the DIP sensor.
FIG. 13 is a side view thereof, and FIGS. 14(a) and (b) are plan views showing the shapes of the first and second light-shielding masks, respectively.
15(a) and 15(b) show a fourth modification of the DIP sensor, FIG. 15(a) is a plan view thereof, and FIG.
b) is a side view thereof, and Figures 16 and 17 show a fifth modification of the DIP sensor; Figure 16 is a side view thereof;
FIGS. 17(a) and 17(b) are graphs showing the properties of light transmittance of a primary characteristic ND filter and a secondary characteristic ND filter, respectively, and FIG. 18 is a side view showing a conventional optical position detection device. Fig. 19 is a perspective view showing a conventional surface-split type optical position detection device, Fig. 20 is a perspective view showing a conventional double-side split type optical position detection device, and Figs. 21 and 22 are conventional movable body positions. FIG. 1 is an overall configuration diagram showing a detection device. In the figure, 1- laser light source, 2, 2A- movable body, 2
a-X-axis stage, 2b-Y-axis stage, 2c --
Z-axis stage, 3-fixing part, 4-incandescent lamp as light source, 5,5A to 5E-DIP sensor as photoelectric converter, 5-1 to 5-n.-photodiode as photoelectric converter, 6- Arithmetic unit, 7.-pinhole, 8.-optical fiber as light source, 9. condensing lens, 11.1la-first
Resistive layer, llb. 11c - band-shaped resistance layer portion, 12, 12a - second resistance layer, 13 - depletion layer, 19-1 to 19-3 - photodiode as photoelectric converter, 22a - first light shielding mask, 22b - 2nd light shielding mask, 27 - photodiode as photoelectric converter, 28 - first light shielding mask (liquid crystal shutter), 29 = - second light shielding mask (liquid crystal shutter), 35 to 37 - as photoelectric converter Photomaru, 38-
A first-order characteristic ND filter as a first-order characteristic optical filter,
39 - Secondary characteristic ND filter as a secondary characteristic optical filter, DIP sensor as a 50.5OA-1 photoelectric converter. L-light beam. Patent applicant: Kobe Steel, Ltd.

Claims (2)

[Claims] (1) A light beam irradiated from the movable body side or the fixed part side is made incident on the photoelectric converter on the fixed part side or the movable body side, and the light intensity of the light beam and the above photoelectric conversion are weighted by the light intensity. The average value of the distance between the end of the body and the incident position of the light beam, and the root mean square value of the distance between the end of the photoelectric converter and the incident position of the light beam, weighted by the light intensity. Detected by photoelectric converter,
Based on the detected light intensity and the average value, a primary output proportional to the average value of the distance between the end of the photoelectric converter and the incident position of the light beam is extracted, and the detected light is After extracting the secondary output proportional to the root mean square value of the distance between the end of the photoelectric converter and the incident position of the light beam based on the intensity and the root mean square value, the The incident position of the light beam is detected, the dispersion of the light beam is calculated and detected based on the above primary output and the secondary output, and then the movable body is moved based on the detected incident position and dispersion of the light beam. A method for detecting the position of a movable body, the method comprising: calculating the position of the movable body relative to the fixed part. (2) A light source that irradiates a light beam and a photoelectric converter that receives the light beam from the light source are each fixed to either a movable body or a fixed part, and the photoelectric converter is connected to the same photoelectric converter. In order to detect the primary output proportional to the average value of the distance between the end of the photoelectric converter and the incident position of the light beam, the width direction is proportional to the same distance at the same distance from the end of the photoelectric converter. In order to detect a secondary output proportional to the root mean square value of the distance between the end of the photoelectric converter and the incident position of the light beam, the It is configured to be separated and insulated at a position in the width direction proportional to the square of the same distance at the same distance position according to the distance, and calculates the incident position and dispersion of the light beam based on the output from the photoelectric converter, and calculates these incident positions. and a calculation unit that calculates the position of the movable body with respect to the fixed part from the dispersion.