JPH0617786B2 - Linear motion measuring device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a linear motion measuring device for performing accuracy inspection of linear motion devices such as machine tools, optical machines, and measuring machines.

[Conventional technology]

Generally, a device that moves linearly is an X-axis table, XY-
Although moving tables such as Z-axis tables are used, it is an important premise to measure the linear motion accuracy of these moving tables with high accuracy in order to achieve the intended purpose.

By the way, as shown in FIG. 9, when a moving body M such as a machine tool that moves linearly moves along the Z-axis, for example, in addition to the positioning error e _{Z in} the Z-axis direction, X accompanying the movement in the X-axis direction.
Axial displacement error e _X , Y-axis displacement error e due to movement in the Y-axis direction
Six components, a displacement error consisting of three components of _Y , a pitching error α due to pitching around the X axis, a yawing error β due to yawing around the Y axis, and a rolling error γ due to rolling around the Z axis. It is known that an error of occurs.

In addition, in the prior art, it is possible to simultaneously measure four component errors out of these six component errors, that is, four components of X-axis displacement error e _X , Y-axis displacement error e _Y , pitching error α, and yawing error β. As the prior art on the linear motion measuring device described in (a) Takada, Yoshida, Maeda: “Measurement of linear motion accuracy using a laser beam” Proc. Of the Seiki Society Autumn Meeting, 1984, P132, P133 (b) It is known that sophistication of linear motion accuracy inspection in machining centers, edited by Foundation for Machine Tool Technology (May 1985), etc.

In each of these prior arts, a first polarizing beam splitter, a corner cube prism and a reflecting mirror are provided on the linear moving body side, and a second polarizing beam splitter, half mirror, collimator on the same axis line on the measuring device side. A lens is provided, and a laser generation device for generating linearly polarized light and a quarter wavelength plate are provided on the half mirror.

And the luminous flux from the light source is a quarter wavelength plate, a half mirror,
It reaches the first corner cube prism through the collimator lens and is divided into a horizontal polarization component P and a vertical polarization component S, and the vertical polarization component S is doubled by the corner cube prism by a displacement amount ΔS of the prism. The reflected wave has a displacement of 2ΔS, and the reflected wave is reflected by the second polarized beam splitter through the first polarized beam splitter, the collimator lens with the focal length f, and the half mirror, and then is used for displacement detection. The four-quadrant photo sensor of (1) receives light, and the output signals from this are calculated as an X-axis displacement error e _X and a Y-axis displacement error e _Y.

Furthermore, the horizontal polarization component P split by the first polarization beam splitter becomes a reflected wave that is twice the tilt angle θ of the reflecting mirror,
This reflected wave is transmitted through the second polarization beam splitter via the first corner cube prism, collimator lens, and half mirror, and then received by the four-quadrant photosensor for angle detection as displacement d≈2θf. The output signal is calculated as a pitching error α and a yawing error β.

[Problems to be solved by the invention]

According to the above-mentioned prior art, firstly, of the six components of the error generated when the linear moving body moves, four components can be measured at the same time, but the rolling error .gamma. There was a problem that it could not be measured.

Secondly, the laser generator generates a considerable amount of heat when oscillating a laser, and the laser tube itself is thermally deformed to change the laser output, but no consideration is given to the change in the light source itself. Therefore, there is a problem that the measurement accuracy is lowered.

Thirdly, the reflected wave from the corner cube prism and the reflected wave from the reflecting mirror pass on the same optical path, and pass through the collimator lens in the meantime. Therefore, the displacement of the linear moving body Δ
Even if a corner cube prism is used to expand S to double the displacement 2ΔS, the expanded displacement amount is reduced while the reflected wave is transmitted through the collimator lens, and the detection is performed by the 4-quadrant photosensor for displacement detection. There is a problem that the resolution becomes small.

The present invention has been made in view of the above problems of the prior art. Not only is it possible to simultaneously measure the error factors of the five components including the rolling error, but also the change factor of the light flux generating means itself is corrected. A linear motion measuring device is provided, which enlarges the displacement of a linear moving body four times or more, and uses the displacement detecting optical path and the angle detecting optical path as separate optical paths to significantly improve the measurement accuracy. To aim.

[Means for solving problems]

In order to solve the above problems, the linear motion measuring apparatus according to the present invention measures an error generated when a linear motion body makes a linear motion on a horizontal plane or on a vertical plane orthogonal to the horizontal plane.

The feature of the configuration adopted by the present invention is that the linearly moving body is arranged so as to be moved together with the linearly moving body so as to be spaced apart from each other in the horizontal direction or the vertical direction. First and second displacement prisms for displacing the light flux incident from the pair as parallel reflected light, and the linear motion body so as to move together with the linear motion body, and the first and second displacement prisms. A reflecting mirror for reflecting the light flux incident on the prism and the light flux incident from two directions, a light flux generating means for generating linearly polarized light having a vibrating surface of a predetermined angle as a light flux, and a light flux generated by the light flux generating means for generating the light flux. Correction position detecting means for detecting the displacement of the light source of the portion itself as a two-dimensional position, and the light flux generated by the light flux generating means on the side of the linear moving body.
First displacement magnifying means for magnifying the amount of displacement of the displacement prism by 2n times by reciprocating between the first and second displacement magnifying means, and the luminous flux magnified and derived from the first displacement magnifying means. Two
A first position detecting means for detecting the position as a dimensional position, and a second luminous flux generated by the luminous flux generating means on the side of the linear moving body.
Second displacement magnifying means for magnifying the amount of displacement of the displacement prism by 2n times by reciprocating between the second displacement magnifying means and the second displacement prism, and the luminous flux magnified and derived from the second displacement magnifying means. Two
A second position detecting means for detecting the position as a dimensional position, and a light beam emitted from the first or second displacement magnifying means reflected by the reflecting mirror on the moving body side and passing the reflected light through a lens. Therefore, the angle deriving means for deriving the tilt angle of the reflecting mirror, the angle detecting means with the tilt angle derived by the angle deriving means as a two-dimensional position, the correction position detecting means, and the first and second positions. A calculating means for calculating a horizontal displacement error, a vertical displacement error and a rolling error of the linear moving body based on an output signal from the detecting means, and a pitching error and a yawing error based on an output signal from the angle detecting means. It consists of and.

[Action]

With the above configuration, the correction position detecting means detects the displacement of the plateau of the light flux generating section itself as a two-dimensional position by the light flux generated by the light flux generating means.

Further, the displacement magnifying means reciprocates the light flux generated by the light flux generating means back and forth with the first displacement prism on the linear moving body side n times, thereby magnifying the displacement amount of the displacement prism by 2n times, and at the first position. The detection means expands the derived luminous flux to 2
Detect as a dimensional position.

Similarly, the second displacement magnifying means reciprocates the light flux generated by the light flux generating means with the second displacement prism on the linear moving body side n times to magnify the displacement amount of the displacement prism by 2n times. The second position detection means detects the expanded and derived light flux as a two-dimensional position.

Further, the angle deriving means reflects the light flux emitted from the first or second displacement magnifying means by the reflection curve on the moving body side,
The tilt angle of the reflecting mirror is derived by passing the reflected light through the lens, and the angle detecting means detects the tilt angle derived by the angle detecting means as a two-dimensional position.

As a result, the calculating means calculates the horizontal displacement error, the vertical displacement error of the linear moving body based on the output signals from the correction position detecting means, the first position detecting means, and the second position detecting means. The rolling error is calculated, and the pitching error and the yawing error are calculated based on the output signal from the angle detecting means.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

First, FIG. 1 shows an overall configuration diagram of the present embodiment. In FIG. 1, reference numeral 1 denotes a linear moving body such as a machine tool, and the linear moving body 1 is configured to reciprocate linearly in the left-right direction of the paper. I'm running. Reference numeral 2 denotes a detection block attached to the linear moving body 1. The detection block 2 has a first displacement detecting corner cube prism 3 and a second displacement detecting corner cube prism 4 having a predetermined dimension L. The angle detection reflecting mirror 5 is arranged at a position different from each of the corner cube prisms 3 and 4 while being arranged in the horizontal direction (vertical direction of the paper).

Here, the corner cube prisms 3 and 4 are for displacing a light beam incident from a direction orthogonal to the arrangement direction of the corner cube prisms 3 and 4 as reflected light parallel to the light. Further, the reflecting mirror 5 is adapted to reflect a light beam incident from the same direction as a light beam incident on the corner cube prisms 3 and 4 in the same optical path.

Further, 11 is a measuring device main body for measuring each error component generated in the linear moving body 1, and the measuring device main body 11 is formed as a movable bed, and each device described later is arranged as shown in the drawing. Reference numeral 12 denotes a laser generator. The laser generator 12 uses, for example, a Ne-He laser source having an output of 3 to 10 mW, and the light beam B emitted from the laser source is 45 ° with respect to the paper surface as shown in FIG. It is a linearly polarized light having an oscillating plane and can be divided into a horizontal polarization component P and a vertical polarization component S by polarization beam splitters 19 and 25 described later.

Reference numerals 13 and 14 are reflecting mirrors that reflect the light beam output from the laser generator 12 and change the optical path toward the first displacement detecting corner cube prism 3, and 15 is a light beam expander that expands the light beam reflected by the reflecting mirror 14. The luminous flux expander 15 includes a convex lens 5A, a pinhole 5B, an iris diaphragm 15C, and another convex lens 15D, and expands the luminous flux by about 6 times.

Reference numeral 16 denotes a first half mirror which is provided on the optical path at a stage subsequent to the light beam expander 15, and the light beam reflected by the half mirror-1b is a four-quadrant (two-dimensional) photosensor 17 for correction.
Is received by. Here, the photo sensor 17 detects the displacement of the laser source including thermal deformation of the laser tube itself of the laser generator 12 by the action described later, and the four-quadrant photo for the first and second position detection described later. It is used to correct the values detected by the sensors 23 and 29 and obtain the true error that has occurred in the linear motion body 1.

Next, 19 is a first polarization beam splitter provided on the optical path emitted from the beam expander 15 via a second half mirror 18 provided next to the half mirror 16.
Reference numeral 0 denotes a first quarter-wave plate provided between the polarization beam splitter 19 and the first displacement detecting corner cube prism 3 on the detection block 2 side, and 21 denotes an upper piece of the polarization beam splitter 19. These polarized beam splitters 1 are the fixed first displacement-increasing corner cube prisms.
The 9, 1/4 wavelength plate 20 and the corner cube prism 21 constitute the first displacement magnifying means 22 according to the present embodiment. Here, the polarization beam splitter 19 has a property of transmitting the horizontally polarized component P and reflecting the vertically polarized component S of the incident linearly polarized light. On the other hand, the quarter-wave plate 20 converts linearly polarized light into circularly polarized light and converts circularly polarized light into linearly polarized light.

Now, the operation of the first displacement magnifying means 22 having the above structure will be described with reference to FIG. Now, in FIG. 3, it is assumed that the first displacement detecting corner cube prism 3 is displaced from the normal position by the displacement ΔS due to the linear moving body 1 side, and the horizontal polarization component P of the linearly polarized light is The vertical polarization component is represented as ".", And the clockwise circular polarization is Counterclockwise circularly polarized light Shall be represented by. Now, the polarization beam splitter 19
The linearly polarized light with a vibration plane of 45 ° incident on the
And a vertical polarization component S, and only the horizontal polarization component P transmits this and passes through the quarter-wave plate 20. At this time, the horizontal polarization component P is converted into counterclockwise circular polarization. The circularly polarized light beam is reflected by the first displacement-detecting corner cube prism 3 displaced by ΔS, passes through the quarter-wave plate 20 again, and becomes a vertical polarization component S.
Enter 9 again. Then, this vertical polarization component S is reflected by the polarization beam splitter 19 and then reflected by the first displacement-increasing corner cube prism 21 and is then reflected by entering the polarization beam splitter 19 three times. pass. When passing through the quarter-wave plate 20, the vertically polarized component S becomes clockwise circularly polarized light, which is reflected again by the first displacement detecting corner cube prism 3 and passes through the quarter-wave plate 20 four times. , Becomes a horizontal polarization component P and enters the polarization beam splitter 19. Thus, the horizontal polarization component P is transmitted through the polarization beam splitter 19, and the polarization beam splitter 19 and the first displacement detecting corner cube prism 3 are reciprocated twice. The displacement ΔS of 3 can be expanded to a displacement of 4 times, that is, 4ΔS.

On the other hand, reference numeral 23 denotes a first position detecting four-quadrant (two-dimensional) for receiving a light beam composed of a horizontal polarization component P that has passed through the polarization beam splitter 19 which constitutes the first displacement magnifying means 22.
Outputs from the photo sensor and the photo sensor 23 are used for calculation of an X-axis displacement error e _X , a Y-axis displacement error e _Y , and a rolling error γ, as described later.

Next, 24 is a reflecting mirror that reflects the light flux reflected by the second half mirror 18 described above, and changes the optical path toward the second corner cube prism 4 for displacement detection, and 25 is reflected by the reflecting mirror 24. A second polarization beam splitter 26 provided on the optical path is a second 1/2 provided between the polarization beam splitter 5 and the corner cube prism 4.
The four-wavelength plates 20 and 27 are second displacement-increasing corner cube prisms fixed to the upper piece of the polarization beam splitter 25.
The fifth, quarter-wave plate 26 and the corner cube prism 27 constitute the second displacement magnifying means 28 according to this embodiment. The second displacement magnifying means 28 magnifies the displacement ΔS ′ of the second displacement detecting corner-cube prism 4 to a quadruple displacement 4ΔS ′, like the first displacement magnifying means described above. There is no change in.

On the other hand, reference numeral 29 denotes a second position detecting four-quadrant (two-dimensional) photosensor for receiving the light beam transmitted through the polarization beam splitter 25 of the second displacement magnifying means 28.
Is used to calculate the X-axis displacement error e _X , the Y-axis displacement error e _Y , and the rolling error γ in cooperation with the first photosensor 23 described above.

Further, 30 is a third polarization beam splitter into which the vertical polarization component S reflected by the first polarization beam splitter 19 is incident as another optical path, and 31 is the polarization beam splitter 3
0/3 and the third 1/4 provided between the angle detection reflecting mirror 5
Reference numeral 32 denotes a wave plate, and 32 denotes a collimator lens having a focal length f for converging the light beam transmitted through the polarization beam splitter 30 toward an angle detecting four-quadrant photo sensor 34, which will be described later. The collimator lens 32 constitutes the angle deriving means 33 according to the present embodiment, and these are provided on the optical path including the reflecting mirror 5 unlike the optical path of the first displacement magnifying means 22.

Here, the operation of the angle deriving means 33 having the above-mentioned configuration will be described with reference to FIG. When the vertical polarization component S reflected by the linearly polarized light that has entered the first polarization beam splitter 19 is incident on the third polarization beam splitter 30, the vertical polarization component S is reflected and It passes through the wave plate 31 and becomes clockwise circularly polarized light. And
This circularly polarized light is reflected by the angle detection reflecting mirror 5, again transmitted through the quarter-wave plate 31, becomes a horizontal polarization component P, passes through the polarization beam splitter 30, is refracted by the collimator lens 32, and is then detected by the angle detection photo. It is incident on the sensor 34. Now, assuming that there is an inclination angle θ in the angle detecting mirror 5, the displacement d in the angle detecting photosensor 34 is d≈2θf ………… (1 ), The inclination angle θ can be converted into the displacement d and derived.

On the other hand, 34 is a four-quadrant (two-dimensional) photosensor for angle detection which receives the light flux from the angle deriving means 33. The photosensor 34 is arranged at the focal length f of the collimator lens 32 and has a pitching error α, It is used to calculate the yawing error β.

Next, the four-quadrant photosensors 17, 23, 2 described above are used.
The general configuration and operation of 9, 34 will be described with reference to FIG.

Now, when this photosensor is typically represented by reference numeral 100, the photosensor 100 is composed of a silicon photodiode having a light receiving surface 101, and has electrodes a, b, c, and d at each corner. Then, when an optical spot 102 is applied to a position on the light receiving surface 101, an electric charge is generated, and the electric charge flows through the low resistance layer toward each of the electrodes a to d. Since the current is inversely proportional to the distance to each of the electrodes a to d, the position of the light spot 102 can be obtained by the ratio of the individual current to the total current.

That is, the sum of the photocurrents is IΣ, and the photocurrents of the electrodes a to d are I
_{Let a} , I _b , I _c , and I _d be I _Σ = I _a + I _b + I _c + I _d (2) If the photocurrent in the X-axis + direction is I _{X +} and the one direction is I _X- , Therefore, the deviation of the photocurrent on the X axis with respect to the sum IΣ is Then, if the distance from the center of the X-axis and Y-axis of the photosensor 100 to the electrode is l and the X-axis distance to the optical spot 102 is X, then X is given by equation (6).

Similarly, if the photocurrent in the + direction of the Y axis is I _{Y +} and the photocurrent in the one direction is I _Y− , If the Y-axis distance from the center of the photo sensor 100 to the optical spot 102 is Y, Then, the barycentric positions X and Y of the optical spot 102 on the photosensor 100 are obtained.

Then, in order to execute the operations of the above equations (2) to (8), the sixth
The arithmetic unit 200 shown in the figure is used. That is, adders 201, 202, 203 and ₂₀₄ for calculating I _{X +} , I _X− , I _{Y +} and I _Y− shown in the equations (3) and (7), and I _{X +}
Subtractor 2 for calculating −I _X− and I _{Y +} −I _Y− respectively
05 and 206, an adder 207 that calculates the total sum IΣ shown in equation (2), and an optical spot 10 shown in equations (6) and (8), respectively.
2's It is composed of dividers 208 and 209 that calculate

In addition, the photo sensor 100 as shown in FIG. 5 and FIG.
The arithmetic unit 200 is known as a semiconductor position detecting element manufactured by Hamamatsu Photonics KK, for example.

Now, next, the photosensor shown in FIG. 5, that is, the correction photosensor 17, the first position detection photosensor 23,
A circuit configuration and an operating principle for calculating 5 components out of 6 components using the second position detecting photosensor 29 and the angle detecting photosensor 34 will be described with reference to FIGS. 7 and 8.

In FIG. 7, reference numeral 41 denotes an arithmetic unit, and the arithmetic unit 41 has arithmetic units 42, 43, 44, 45 having the same configuration as the arithmetic unit 200 representatively shown in FIG. Subtractors 46, 47, 48, 49 provided at the next stage of 44 and adders 50, 5 provided at the next stage of the subtractors 46 to 49.
1 and subtractor 52, and the adders 50 and 51 and subtractor 5
Dividers 53, 54, 55 provided in the next stage of 2 respectively
It consists of and. Then, the correction photo sensor 1
The detection signal from 7 is input to the arithmetic unit 44 and received at the positions X ₀ and Y _{0 of} the optical spot (this is the position of the optical spot output from the arithmetic unit 200). Corresponding to each of the detection signals from the first and second position detecting photosensors 23 and 29 and the angle detecting photosensor 34, respectively. The position of the light spot is X ₁ , Y ₁ ,
Output as X ₂ , Y ₂ , X ₃ , Y ₃ . On the other hand, the X axis displacement error e _X from the divider 53 and Y from the divider 54.
The axial displacement error e _Y is transferred from the divider 55 to the rolling error γ.
From the calculator 45, a pitching error α and a yawing error β are output.

By the way, each error component e _X ,
The principle of calculation of e _Y and γ will be described with reference to FIG.

In FIG. 8, the position of the light spot by the correction photosensor 17 is P ₀ (X ₀ , Y ₀ ), and the position of the light spot by the first and second position detection photosensors 23 and 29 is P ₁ ( X ₁ , Y ₁ ) and P ₂ (X ₂ , Y ₂ ), and the distance between the photosensors 23 and 29 is L.
X-axis between the light spot _{P 0} and _{P 1,} the difference between the measured position in the Y-axis direction (displacement amount) ΔX _1, ΔY ₁ is Next, likewise the difference between the measured position between the optical pot _{P 0} and _{P 2} (displacement amount) ΔX _2, ΔY ₂ is Becomes

Therefore, the calculation by the equation (9) is performed by the subtractor 4 of the calculation device 41.
8 and 49, and the calculation by the equation (10) is executed by subtractors 46 and 47.

Here, ΔX ₁ and ΔX ₂ are displacements in the horizontal direction (X-axis direction). Therefore, if the error component Δe _{X ′ of the} linear moving body 1 in the X-axis direction is approximated, Δe _X ′ ≈ΔX ₁ ≈ΔX ₂ (11), but in the present embodiment, in order to further improve the measurement accuracy, after these values are added by the adder 50,
By dividing by the divider 53 into 1/2, the average error component Δe _X at two points in the X-axis direction is Can be calculated as

Similarly, since ΔY ₁ and ΔY ₂ are displacements in the vertical direction (Y-axis direction), assuming that the error component Δe _Y ′ of the linear moving body 1 in the Y-axis direction is Δe _Y ′ ≈ΔY ₁ ≈ ΔY ₂ (13) is obtained, but the average error component Δe _Y in the Y-axis direction is calculated by the adder 51 and the divider 54 as described above. Can be calculated as

Further, the rolling error γ is an error due to rolling around the Z axis with the Z axis as the center, and therefore, with respect to the distance L between the first and second position detecting photosensors 23 and 29, If the error component Δe _{X in the} X-axis direction is sufficiently small, the rolling error γ is Is required as. Therefore, the calculation by the equation (13), the subtracter 52 executes the subtraction of ΔY ₂ −ΔY ₁ , and the divider 55 executes the division by the distance L.

Further, the pitching error α is an error due to the pitching around the X axis with the X axis as the center, and the yawing error β is Y.
This is an error due to yawing around the axis, and the calculation of each of these error components will be described.

First, as can be understood from FIG. 5, when the light spot of the photosensor 100 is considered by a general concept, pitching α ′ and yawing β ′ are It is represented by.

However, when the position of the light spot of the angle detecting photosensor 34 is seen, it is the position of the displacement d depending on the tilt angle θ of the angle detecting reflecting mirror 5 as is clear from the equation (1),
The output from the calculator 45, i.e., X-axis direction displacement amount _X 3, Y-axis direction displacement amount _{Y 3} are Will be immediately represented as, and can be directly derived from the arithmetic unit 45.

Thus, according to the linear motion measuring device according to the present embodiment,
Using the linearly polarized light from the laser generator 11, among the six component error factors generated in the linear motion body 1, an error e of five components
_{Since X 1} , e _Y , α, β and γ can be simultaneously measured, the linear moving body 1 can be positioned with extremely high accuracy. Therefore, the linear motion accuracy of the machine tool, the measuring machine, etc. can be improved, and the man-hour for accuracy inspection can be reduced.

In addition to the laser generator 12, the measuring apparatus main body 11 is fixedly provided with an optical system including the photosensors 17, 23, 29, and 34. Therefore, correction is performed according to the cause on the laser generator 12 side. If the position of the light spot P ₀ of the photo sensor 17 for use moves, the positions of the light spots P ₁ and P ₂ of the first and second position detecting photo sensors 23 and 29 also move by the same variable position. Therefore, the displacements shown in the equations (9) and (10) are not affected by the laser light source of the laser generator 12,
It is possible to derive only the X-axis direction displacement error e _X , the Y-axis direction displacement error e _Y , and the rolling error γ that are actually occurring in the linear moving body 1.

Further, the optical path system including the first and second displacement magnifying means 22 and 28 and the optical path system including the angle deriving means 33 are different optical paths, and the collimator lens 3 constituting the angle deriving means 33.
Since 2 does not obstruct the optical path to the first and second displacement magnifying means 22 and 28, the position detecting photosensors 23 and 29 are arranged in the first and second displacement detecting corner cube prisms 3 and 4, respectively. The light can be received while the displacement of 4 is magnified four times, and the resolution can be improved.

Furthermore, the X-axis direction displacement error e _X and the Y-axis direction displacement error e _Y output from the dividers 53 and 54 can be derived as an average error at two points in the X-axis direction and the Y-axis direction. The measurement accuracy of the displacement errors e _X and e _Y can be made extremely high.

In the embodiment, the first and second displacement magnifying means 22, 28 are used.
Is the first and second displacement detecting corner cube prisms 3,
2 round trips to and from the corner cube prism 3,
Although it has been described that the displacement of No. 4 is magnified four times, it can be magnified by 2n times corresponding to the number of round trips n between these, and this can be appropriately changed by the configuration of the displacement magnifying means 22, 28. Can be set to.

In addition, in the arithmetic unit 41 of the embodiment, in order to calculate the X-axis direction displacement error e _X and the Y-axis direction displacement error e _Y with high accuracy, the adders 50 and 51 and the dividers 53 and 54 are used respectively and averaged. Although it has been described that the value is obtained, equation (11), (13)
As in the formula, either _{one of} the X-axis direction displacements ΔX ₁ and ΔX ₂ or one of the Y-axis direction displacements ΔY ₁ and ΔY ₂ may be used as the displacement errors e _X and e _Y.

Further, right-angle prisms may be used as the first and second corner cube prisms 3 and 4 for detecting displacement.
4, the light flux expander 15 and the like may be appropriately adopted.

〔The invention's effect〕

The linear motion measuring device according to the present invention is as described in detail above, and is capable of simultaneously measuring the error of 5 components out of the error of 6 components generated when the linear moving body makes a linear motion. It is possible to eliminate the measurement error factor due to the means, and since the optical path system of the angle detection means is different from the optical path system of the displacement magnifying means, it is possible to increase the resolution and to perform highly accurate linear motion inspection. It will be possible.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an overall configuration diagram of the present embodiment, and FIG. 2 is a schematic diagram showing a relationship between a light beam output from a laser generator and a horizontal polarization component and a vertical polarization component. FIG. 4 is an explanatory diagram showing a displacement magnifying detection operation by the first displacement magnifying means, FIG. 4 is an explanatory diagram showing an angle deriving operation by the angle deriving means, and FIG. 5 is an explanatory diagram showing a general configuration of a 4-quadrant photosensor. FIG. 6 is a general circuit configuration diagram of an arithmetic unit for calculating the light spot position by the photosensor shown in FIG. 5, and FIG. 7 is a circuit configuration diagram of the arithmetic unit of this embodiment for calculating each error component, and FIG. FIG. 9 is an explanatory diagram showing the principle of calculation of the error component, and FIG. 9 is an explanatory diagram showing the error component in the X-, Y-, and Z-axis directions. 1 ... Linear moving body, 2 ... Detection block, 3 ... First displacement detecting corner cube prism, 4 ... Second displacement detecting corner cube prism, 5 ... Angle detecting reflecting mirror, 11 ... … Measuring device body, 12 …… Laser generator, 1
5 ... Luminous flux expander, 17 ... 4-quadrant photosensor for correction, 19 ... First polarization beam splitter, 20 ... First quarter-wave plate, 21 First displacement-increasing corner cube prism, 22 ... first displacement magnifying means, 23 ... first
4-quadrant photosensor for position detection, 25 ... second polarization beam splitter, 26 ... second quarter-wave plate, 27 ...
… Second displacement-increasing corner cube prism, 28 ……
Second displacement magnifying means, 29 ... second four-quadrant photosensor for position detection, 30 ... third polarization beam splitter,
31 ... Third quarter-wave plate, 32 ... Collimator lens, 33 ... Angle deriving means, 34 ... 4-quadrant photosensor for angle detection, 41 ... Arithmetic unit, 42-45 ... Arithmetic unit, 46-49, 52 ... Subtractor, 50, 51 ... Adder, 53-55 ... Divider

Claims (1)

[Claims] 1. A linear motion measuring device for measuring an error generated when a linear motion body makes a linear motion on a horizontal plane or on a vertical plane orthogonal to the horizontal plane, wherein the linear motion body is configured to move together with the linear motion body. First and second displacement prisms which are arranged separately from each other in a horizontal direction or a vertical direction of the linear moving body and which displaces a light beam incident from a direction orthogonal to the disposing direction as parallel reflected light; A reflecting mirror which is provided on the linear moving body so as to move together with the body and which reflects a light beam incident from the same direction as the light beam incident on the first and second displacement prisms, and a vibrating surface having a predetermined angle. A light flux generating means for generating linearly polarized light as a light flux, a correction position detecting means for detecting the displacement of the light source of the light flux generating portion itself as a two-dimensional position by the light flux generated by the light flux generating means; The first light flux with live means of the linear motion-side
First displacement magnifying means for magnifying the amount of displacement of the displacement prism by 2n times by reciprocating between the first and second displacement magnifying means, and the luminous flux magnified and derived from the first displacement magnifying means. Two
A first position detecting means for detecting the position as a dimensional position, and a second luminous flux generated by the luminous flux generating means on the side of the linear moving body.
Second displacement magnifying means for magnifying the amount of displacement of the displacement prism by 2n times by reciprocating between the second displacement magnifying means and the second displacement prism, and the luminous flux magnified and derived from the second displacement magnifying means. Two
A second position detecting means for detecting the position as a dimensional position, and a light beam emitted from the first or second displacement magnifying means reflected by the reflecting mirror on the moving body side and passing the reflected light through a lens. Therefore, an angle deriving means for deriving the tilt angle of the reflecting mirror, an angle detecting means for detecting the tilt angle derived by the angle deriving means as a two-dimensional position, the correction position detecting means, the first and second The horizontal displacement error, the vertical displacement error and the rolling error of the linear moving body are calculated based on the output signal from the position detecting means, and the pitching error and the yawing error are calculated based on the output signal from the angle detecting means. A linear motion measuring device comprising: a calculating means.