JPH0814818A - Measurement method and device for installation state of parts using bidirectional optical beam - Google Patents

Abstract

PURPOSE:To discriminate an error cause by measuring a distance from an optical beam advancing unidirectionally after transmission through a measurement object part and an optical beam advancing in an opposite direction as a component of a bidirectional beam before the transmission. CONSTITUTION:An optical beam 2A straight advances from the center of a lens 3A to the center of a lens 3B. This beam 2A, however, turns into an optical beam 2AT diffracted by such an angle alpha as corresponding to the inclination angle DELTAtheta of the lens 3B, and advances in a rightward direction without being superposed on an optical beam 2B. Furthermore, the beam 2B incident on the center of the lens 3B from the right side turns into an optical beam 2BT inclined in the opposite direction of the beam 2AT by an angle alpha and comes to be incident on the lens 3A at a position of the off center thereof. Thus, the beam 2B is not superposed on the beam 2A. Regarding judgement about whether the dislocation of the two optical beams is attributable to the deviation of a lens angle or to the deviation of a lens position, the appearance of the beams 2AT and 2BT at opposite sides relative to a bidirectional optical beam reference position is judged as an angular deviation, while the appearance of the beams 2AT and 2BT at the same side is judged as a positional deviation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring the position and angle of optical parts, mechanical parts, etc., that is, the installation state, and a measuring apparatus therefor.

[0002]

2. Description of the Related Art Many methods based on various principles have been put to practical use in the measurement of the installation state such as the position and angle of optical parts and mechanical parts. It is used properly according to the purpose. As one of them, there is a measuring method using one light beam. FIG. 4 shows a method of measuring the relative accuracy of two lenses with one light beam. When the two lenses 3A and 3B are arranged ideally (without error) with respect to the reference line 1, the direction of the light beam 2 traveling from left to right is the same even if it passes through the lenses 3A and 3B. Continue straight on the reference line 1,
The reference line 1 reaches the same position as the point O intersecting the screen 4.

Now, as shown in FIG. 4A, the lenses 3A and 3
If the center of B is on the reference line 1 and the lens 3B is inclined by Δθ, the light beam 2 travels straight on the reference line 1 until it enters the lens 3B, but exits the lens 3B. The emitted light beam 2 deviates from the reference line 1 and reaches the position of the point P ₁ on the screen 4 which is different from the point O.

On the other hand, as shown in FIG. 4B, the lenses 3A and 3
Both B are orthogonal to the reference line 1, but if the center of the lens 3B is separated from the reference line 1 by a distance d, the light beam 2 emitted from the lens 3A is located at a position different from the optical axis of the lens 3B. In order to enter, the traveling direction is changed here and the point P ₂ on the screen 4 is reached. In this method, the lens tilt angle Δθ or the position shift amount d can be obtained by measuring the position shift distances OP ₁ and OP ₂ of the light beam on the screen. It is impossible to distinguish which is the cause of the shift.

FIG. 5 shows a method for measuring the inclination angle of a mechanical component having an inclined surface. When the flat surface B of the mechanical component 5 is orthogonal to the reference line 1, when the light beam 2 coming from the left is reflected by the inclined surface A, the angle between the incident light and the reflected light is measured as θ _A, and the angle is flat. The angle θ ₀ of the inclined surface A with respect to the surface B is obtained as half of the angle θ _A. If the flat surface B are inclined by Δθ is measured angle theta _A in the method of FIG. 5 theta _A
= 2 (θ ₀ + Δθ), and Δθ is included in the measured value as an error. Here, in order to eliminate the influence of Δθ, it is indispensable to install the parts such that the flat surface B of the mechanical part is orthogonal to the reference line 1, and in this case, there is a problem that the operation takes time.

As described above, in the conventional measurement using one light beam, it is impossible to distinguish the cause of the relative error between the two lenses, for example, the positional deviation of the lenses or the angular deviation, or the inclination of the component. In the angle measurement, the influence of the tilt angle when the measurement component is installed cannot be eliminated, and thus there is a problem that the measurement accuracy decreases.

In view of the above-mentioned problems, the present invention is capable of distinguishing between an error of a positional deviation and an angular deviation, and also improves the measurement accuracy in tilt angle measurement. The purpose is to provide a measuring method and an apparatus.

[0008]

A book that achieves the above-mentioned object
The invention provides (1) two light beams traveling in opposite directions.
The two bidirectional light beams are combined to form a bidirectional light beam.
The above bidirectional light transmitted through the part to be measured placed in the beam
A light beam that travels in one direction of the beam and the measurement target
The other of the above bidirectional light beams before passing through the component
The feature is to measure the mutual distance between the light beam traveling in the opposite direction.
(2) One along the bidirectional light beam of the part to be measured
On the side of the light beam after transmission and the light beam before transmission
Angle θ corresponding to the distance_AAnd the light beam after passing through on the other side
Angle θ corresponding to the mutual distance with the light beam before transmission_BAnd
The deflection angle due to the angular deviation and the deflection angle due to the positional deviation.
Is (θ_A+ Θ_B) / 2 and (θ_A−θ_B) / 2 and
Characteristic of seeking, (3) proceeding in opposite directions 2
The two light beams are overlapped to form one bidirectional light beam.
One of the parts to be measured placed in this bidirectional light beam
A single point on the surface of the
Reflects the light beam and supports one of the above surfaces
The other side of the bidirectional light beam at one point on the other side
Reflects the light beam traveling in the direction,
Characterized by measuring the mutual distance between the incident light and the reflected light
(4) On one side of the part to be measured along the bidirectional light beam
Angle θ corresponding to the mutual distance between the incident light and the reflected light_AWhen,
The angle θ corresponding to the mutual distance between the incident light and the reflected light on the other side
_BAnd one side above the reference line of the bidirectional light beam
Inclination angle of₀Is θ ₀= Θ_A/ 2 + θ_BAsk by
And (5) optical beam emitted from a visible light laser oscillator.
The collimating lens and the reverse
Equipped with a part that forms a small-diameter collimated beam with a spanner
Eh, two beams of this collimated beam with a beam splitter
Optical beams are split into
The opposite side of the mirror through a reflection mirror and a half mirror
Two beams traveling in the same direction, and a reflection mirror and half
Two optical beads by adding a position and angle adjustment mechanism to the mirror
Mach that overlaps the beams to form a single bidirectional light beam
Equipped with a measurement part of a Zender type optical system and compatible with a half mirror
And installed on the side opposite to the direction of travel of the optical collimated beam.
It is equipped with an imaging camera and a TV monitor for observation and evaluation.
And are characterized.

[0009]

When a light-transmitting component such as a lens is used as the measurement target component, the transmitted light of the bidirectional light beam is refracted to the same side with respect to the reference line of the bidirectional light beam due to the difference between the center position deviation and the angular deviation. It is possible to distinguish and measure by the difference of refraction to the opposite side, and when measuring the inclination angle, the reflection angle is measured by adding the inclination of the other surface to the one surface by the reflected light of the bidirectional light beam. be able to.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will now be described with reference to FIGS. FIG. 1 is a measurement diagram of a two-lens installation state using a bidirectional light beam. 2A is a light beam traveling from left to right, 2B is a light beam traveling in the opposite direction to 2A, and light beams 2A and 2B are Spatial overlapping results in one bidirectional light beam, 3A and 3B are lenses, and lens 3B is inclined by Δθ with respect to lens 3A (see FIG. 1).
(A)), the position is displaced by the distance d (Fig. 1).
(B)). 2A of the light beam 2A transmitted through the lens 3B
The light beam 2B that has passed through T and the lens 3A is referred to as 2BT. In FIG. 1A, the light beam 2A goes straight through the center of the lens 3A toward the center of the lens 3B.
When passing through the lens 3B, the light beam 2AT is deflected by the angle α corresponding to the inclination Δθ of the lens 3B (lower side of the light beam 2B in the figure), and goes to the right without overlapping the light beam 2B. Also, the light beam 2B that has traveled from the right and entered the center of the lens 3B is in the opposite direction to the light beam 2AT by the angle α due to the inclination of the lens 3B (in the figure,
The light beam 2BT tilted to the upper side of A) becomes a lens 3B
Get out of. The light beam 2BT emitted from the lens 3B is moved away from the center of the lens 3A with respect to the lens 3A.
Since the light beam 2BT exits the lens 3A, the light beam 2BT does not overlap the light beam 2A.

On the other hand, in FIG. 1B, the light beam 2A that has passed through the lens 3A and travels straight is incident at a position away from the center by a distance d due to the displacement of the lens 3B.
Then, when the light beam 2A leaves the lens 3B, it becomes a light beam 2AT that is inclined by an angle β (to the lower side of the light beam 2B in the figure) with respect to the light beam 2A corresponding to the positional deviation d, and is emitted as the light beam 2B. Does not overlap with. Also the light beam 2B
The incident condition of the light beam 2A on the lens 3B is the same as the incident condition of the light beam 2A on the lens 3B, but the traveling direction is opposite. Therefore, the direction and angle of deflection of the transmitted light beam 2BT are the same as those of the light beam 2AT. Only the direction to go is opposite. Since this light beam 2BT passes through the lens 3A at a position deviated from the lens center (the lower side of the light beam 2A in the figure), the light beam 2BT exiting the lens 3A is displaced from the center of the lens. It exits the lens 3A at a dependent angle and does not overlap the light beam 2A.

As a result, the lens 3B is different from the lens 3A.
The angular shift amount or the positional shift amount of can be obtained from the distance between the light beam 2B and the transmitted light beam 2AT at a position separated from the lens 3B by a certain distance in the space on the right side of the lens 3B. Then, whether the displacement of the two light beams is caused by the angular displacement or the positional displacement of the lens can be distinguished by the position where the transmitted light beam appears with respect to the bidirectional light beam. That is, the transmitted light beams 2AT and 2BT appear on the opposite sides of the reference position of the bidirectional light beam (in FIG. 1A, the transmitted light beam 2BT with respect to the light beam 2A is on the upper side in the left space of the lens 3A). In this case, the positional deviation is caused by the angular displacement. When the transmitted light beams 2AT and 2BT appear on the same side with respect to the reference position of the bidirectional light beam (in FIG. 1B, the transmitted light beam 2BT is on the lower side), the positional displacement occurs. It can be determined that

When both the angle and the position are deviated,
There are four possible cases depending on the combination of the left and right angular displacement and the vertical positional displacement. In any case, the angular displacement and the positional displacement are distinguished based on FIGS. 1A and 1B. Each size can be calculated. As an example, using FIG. 1C, the angular deviation of FIG.
A case where both of the positional shifts of 1 occur will be described.
Since the deflection of the transmitted light beam 2AT with respect to the light beam 2B is in the same direction, the deflection angle θ _A is obtained by adding the deflection angle α due to the positional deviation and the deflection angle β due to the angular deviation (α +
β). On the other hand, the deflection direction of the transmitted light beam 2BT with respect to the light beam 2A is on the opposite side with respect to the light beam 2A because of the angular deviation and the positional deviation, and therefore the deflection angle θ _B is equal to the difference between them. If the deflection angle α due to the angular displacement is larger than the deflection angle β due to the positional displacement, the transmitted light 2BT emitted from the lens 3B is the light beam 2
It exists above A and its deflection angle θ _B is (α-β).
The deflection angle θ _A can be obtained on the right side of the lens 3B from the distance between the two light beams and the distance from the lens 3B to a position (not shown) for measuring the distance between the light beams.
On the other hand, the transmitted light beam 2BT having the deflection angle θ _B, which has exited the lens 3B, is incident on the lens 2A at the angle as it is, and exits from the lens 2A at the deflection angle γ. The deflection angle γ is obtained from the distance measurement of two light beams at two different places (not shown) on the left side of the lens 2A, and the deflection angle γ is obtained by using a well-known ray determinant. θ _B is obtained. From the two measured deflection angles θ _A and θ _B thus obtained, the deflection angle α due to the angular deviation and the deflection angle β due to the positional deviation can be obtained from the following equations. α = (θ _A + θ _B ) / 2 β = (θ _A −θ _B ) / 2

FIG. 2 shows an example of measuring the angle of a component. 2A and 2B are light beams forming a bidirectional light beam, 2AR and 2BR are reflected lights, 5 is a component to be measured, B is a reference plane of the component, and A is a plane. Is inclined with respect to the B plane by an angle θ ₀ . When the light beam 2A is applied to the A surface of the component 5 in which the B surface is inclined by the angle Δθ with respect to the bidirectional light beam, the angle between the reflected light 2AR and the light beam 2A is θ _A , The inclination angle (θ ₀ + Δθ) of the surface A with respect to the light beam 2A has the following relationship. θ _A = 2 (θ ₀ + Δθ) Similarly, if the angle formed by the light beam 2B and its reflected light 2BR is θ _B , the relationship between the tilt angle Δθ of the B surface also has the following expression. θ _B = 2Δθ From the above two equations, the value of the angle θ ₀ can be obtained by the following equation. θ ₀ = θ _A / 2 + θ _B

FIG. 3 shows an apparatus configuration in which the above-mentioned measurement is carried out. A He-Ne laser 6; a pinhole 7; a collimating lens 8; and an inverse expander for reducing the light beam diameter 9 to 1/20. A small-diameter parallel light beam forming unit and 1
0 total reflection mirror, 11 beam splitter, 12 half mirror, 13 XYZ parallel axis and 6 stages of αβγ rotation axis adjustable, Mach-Zehnder type measurement optical system consisting of 14 DUT, and 15A , 15B coaxial illumination and a CCD camera having a zoom magnifying optical system, and 16A and 16B television monitors having an image processing function.

The light emitted from the laser 6 is converted into a light beam having a diameter of 2 mm by the pinhole 7 and the collimator lens 8 and further converted into a parallel light beam having a diameter of 0.1 mm through the inverse expander 9. This parallel light beam is bent at a right angle by the total reflection mirror 10A, split into two light beams by the beam splitter 11, and one is bent at a right angle by the half mirror 12B, and the measured object 14 is moved from the right direction. The light beam 2B that hits the object 14 is bent at a right angle by the total reflection mirror 10B, and then enters the half mirror 12A. . When the two light beams 2A and 2B thus formed are spatially overlapped to form one beam, a bidirectional light beam is obtained. For this purpose, a semi-transmissive screen (not shown) is placed at the position of the object to be measured 14, and no matter where this screen is located between the half mirrors 12A and 12B, two light beams 2A are projected on the screen. Adjust two 6-axis stages with half mirrors so that 2B becomes one spot. Whether or not the two light beam spots become one on the screen is determined by CCD cameras 15A and 15B.
And confirm through the television monitors 16A and 16B. In the actual measurement, the DUT 14 and the DUT 1 are placed at predetermined positions in FIG.
By installing a semi-transmissive screen (not shown) at a certain distance from the object to be measured 14 at two positions between the 4 and the half mirrors 12A and 12B, and measuring the distance between the spots appearing on the screen. is there. The arrangement of each optical component of the measuring apparatus of the present invention is not limited to that shown in FIG. 5 and may be changed within the scope of the invention.

[0017]

As described above, according to the present invention, it is possible to perform measurement that is difficult with a single light beam, such as determination of factors of positional error between components and high-accuracy measurement of tilt angles that are easily influenced by the postures of components. This can be easily done by simply measuring the distance between two light beams in the space on both sides of the object to be measured using a bidirectional light beam, and the device for this measurement is a laser, expander, CCD. It can be realized with a simple configuration using only general commercial products such as a camera, a beam splitter, and other optical components and a 6-axis adjustment stage. In the embodiment of FIG. 1, when the position adjustment of one lens with respect to the other lens is performed so that the two light beams, the light beam that has passed through the lens and the light beam that has not passed through the lens, overlap each other. In the example of FIG. 2, it is apparent that the present invention can be applied as a component position adjusting method and its device by adjusting the posture of the component so that the incident light and the reflected light with respect to the B surface are matched.

[Brief description of drawings]

FIG. 1 is an explanatory view of a method for measuring relative accuracy of two lenses according to the present invention.

FIG. 2 is an explanatory diagram of a method for measuring a tilt angle of a mechanical component.

FIG. 3 is a block diagram of the apparatus.

FIG. 4 is an explanatory view of a conventional method for measuring relative accuracy of two lenses of one light beam.

FIG. 5 is an explanatory view of a conventional method for measuring a tilt angle of a mechanical component.

[Explanation of symbols]

1 Reference line 2, 2A, 2B, 2AT, 2BT, 2AR, 2BR Light beam 3A, 3B Lens 4 Screen 5 Object to be measured 6 He-Ne laser 7 Pinhole 8 Collimating lens 9 Reverse expander 10A, 10B Total reflection mirror 11 Beam splitter 12A, 12B Half mirror 13A, 13B 6-axis stage 14 DUT 15A, 15B CCD camera 16A, 16B TV monitor

Claims (5)

[Claims] 1. A bidirectional light beam is formed by superposing two light beams traveling in opposite directions to each other, and the bidirectional light beam is transmitted through a component to be measured placed in the bidirectional light beam. A light beam traveling in one direction,
A method for measuring the installation state of a component using a bidirectional light beam, which comprises measuring a mutual distance between the bidirectional light beam that has not passed through the component to be measured and a light beam that travels in the other direction. 2. One of the parts to be measured along the bidirectional light beam.
On the side of the light beam after transmission and the light beam before transmission
Angle θ corresponding to the distance_AAnd the light beam after passing through on the other side
Angle θ corresponding to the mutual distance with the light beam before transmission_BAnd
The deflection angle due to the angular deviation and the deflection angle due to the positional deviation.
Is (θ_A+ Θ_B) / 2 and (θ_A−θ _B) / 2 and
2. The bidirectional light beam according to claim 1, which is obtained.
How to measure the installation status of parts. 3. Two bidirectional light beams advancing in mutually opposite directions are superposed to form one bidirectional light beam, and the bidirectional light beam is placed at one point on one surface of a component to be measured placed in the bidirectional light beam. The light beam that travels in one direction of the light beam is reflected, and the light beam that travels in the other direction of the bidirectional light beam is reflected at one point on the other surface corresponding to the one surface. A method for measuring the installation state of a component using a bidirectional light beam, characterized in that the mutual distance between the incident light and the reflected light of the beam is measured. 4. An angle θ _A corresponding to the mutual distance between incident light and reflected light on one side of the component to be measured along the bidirectional light beam.
And an angle θ _B corresponding to the mutual distance between the incident light and the reflected light on the other side, and the inclination angle θ ₀ of the one side with respect to the reference line of the bidirectional light beam is θ ₀ = θ _A / The method for measuring the installation state of a component by means of a bidirectional light beam according to claim 3, wherein the method is determined by 2 + θ _B. 5. A light beam emitted from a visible light laser oscillator is provided with a collimating lens and a portion for forming a small-diameter light collimated beam by an inverse expander for reducing the light beam diameter, and two light collimated beams are provided by a beam splitter. The light beams are split into two light beams, and each split light collimated beam is made into two beams that travel in opposite directions through the reflection mirror and the half mirror. Furthermore, a mechanism for adjusting the position and angle is added to the reflection mirror and the half mirror. An imaging camera and a TV that are provided with a measurement unit of a Mach-Zehnder type optical system that forms two bidirectional light beams by superimposing two light beams, and is installed on the side opposite to the traveling direction of the optical collimated beam with respect to the half mirror. A device installation state measuring device using a bidirectional light beam, which is provided with an observation and evaluation part of a monitor.