JPH08141767A - Optical axis adjusting device - Google Patents

Abstract

PURPOSE: To automatically execute adjustment of optical axis in a direct drive laser beam machine by operating mounting error of a reflecting mirror from light spot displacement information and axis displacement information. CONSTITUTION: In assembling or adjusting after assembling of a direct drive laser beam machine, by detection the two dimensional displacement of light spot from the center of one side reflecting mirror 11 to a light receiving body through other reflecting mirror 11 by a light spot displacement detecting mechanism 18, the light spot displacement information is obtained. Further, the displacement of center axis between reflecting mirrors 11 is detected by an axis displacement detecting mechanism and the axis displacement information is obtained. The mounting error of reflecting mirror is operated from light spot displacement information and axis displacement information. Based on this mounting error, an optical axis adjusting mechanism 19 outputs an inclined angle to a reflecting mirror tilting mechanism 13 and the mounting error of reflecting mirror is automatically compensated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical axis adjusting device for automatically adjusting a mounting error of a reflecting mirror in a laser processing machine or a laser robot.

[0002]

BACKGROUND OF THE INVENTION Laser processing machine or a laser robot, for example, a material with a CO ₂ laser having KW (hereinafter, referred to as photoreceptor) welding, a device for performing fusing or the like, a laser emitted from a CO ₂ laser The light is guided to a predetermined position on the photoreceptor by using a plurality of reflecting mirrors. However, if there is a mounting error in each reflecting mirror, the laser beam cannot be irradiated to the position intended by the user, and correct welding cannot be performed. The position needs to be adjusted accurately.

Specifically, a weak laser beam of visible light is introduced from the root of the laser processing machine, and the light beam reflected by the first reflecting mirror is used instead of the flange portion for mounting the second reflecting mirror. Receive with the attached focus glass. Next, adjust the first reflecting mirror so that the light spot on the focusing glass is in the center (hereinafter referred to as the optical axis adjustment), and after this adjustment,
The second reflecting mirror is attached, and the focus glass is attached to the mounting flange portion of the third reflecting mirror to adjust the second reflecting mirror. Then, this work is repeated up to the tip.

However, this adjusting method is very complicated, and it takes half a day even if a skilled person carries out the assembly adjustment of one unit or the adjustment after the assembly. Moreover, since the optical axis adjustment is performed by visual inspection, there is a problem in its reliability and accuracy. Therefore, in recent years, an optical axis adjusting device and an optical axis adjusting method for automatically adjusting the optical axis have been disclosed.

FIG. 6 is a block diagram showing a conventional optical axis adjusting device disclosed in, for example, Japanese Patent Laid-Open No. 5-329674.
In the figure, 1 is a laser oscillator, 2a to 2e are joints mounted rotatably around an axis, an electric motor,
It consists of gears and bearings. 3a-3h
Is a reflecting mirror that is slidably and rotatably attached, and includes a slide mechanism and a gimbal mechanism. In addition,
The gimbal mechanism is one in which the reflecting mirrors 3a to 3h are attached to the inner frame so as to be rotatable in the left-right direction, and the inner frame is attached to the outer frame in a vertically rotatable manner. Is. 4 is a beam splitter for separating laser light, 5 and 6 are detectors for laser light, 7 and 8 are detectors 5,
An image processing device for performing image processing of the laser light taken in from 6, and an image display device 9 for displaying images from the image processing devices 7 and 8.

Next, the operation will be described. First, by irradiating the laser beam input port of the reflecting mirror 3a with the laser beam from the laser oscillator 1, the laser beam separated by the beam splitter 4 is passed through the two detectors 5 and 6 and the image processing devices 7 and 8 are connected. The image processing devices 7 and 8 simultaneously display the introduced laser beams on the same image display device 9. Therefore, by rotating only the joint to be measured in a predetermined direction, the locus of the light spot draws a circle. At this time, the reflecting mirrors 3a to 3h are adjusted so that the locus of the light spot passes through the center of the circle of the image display device 9. This adjustment is performed by moving the reflecting mirrors 3a to 3h in small amounts to measure the moving direction and moving amount of the light spot, and using the small amount, moving direction and moving amount of the light spot, the adjusted moving amount to the desired position. Is calculated. In the above-mentioned conventional example, the light receiving body is provided at the end of the optical system, but in an actual laser processing machine or the like, a parabolic mirror or lens for narrowing the laser light is installed.

[0007]

Since the conventional optical axis adjusting device is constructed as described above, in order to correct the mounting error of the reflecting mirrors 3a to 3h,
Since the reflector was manually moved in advance in small amounts, the trajectory of the light spot was measured, the amount of movement to the desired position was calculated, and the reflector was manually adjusted again, so the adjustment work was complicated and many adjustment times were required. There was a problem that time was spent. Further, the detectors 5 and 6 for detecting the position of the light spot, the image processing device 7,
8 and the optical system such as the beam splitter 4, it is necessary to manufacture the optical system.
Furthermore, although the locus of the light spot draws a circle,
In the direct-acting laser processing machine, the locus of the light spot does not draw a circle (it draws a straight line as will be described later), so there is a problem that it cannot be applied to the direct-acting laser processing machine.

The present invention has been made to solve the above-mentioned problems, and the optical axis is automatically adjusted at the time of assembling the laser robot and the direct-acting laser processing machine or at the time of adjustment after the assembly. It is an object of the present invention to obtain an optical axis adjusting device that can be manufactured at low cost and can be applied to a direct-acting laser processing machine.

[0009]

According to a first aspect of the present invention, there is provided an optical axis adjusting device which uses a light spot displacement information read by a light spot displacement detection mechanism and axial displacement information read by a shaft displacement detection mechanism to determine a reflector. The mounting error is calculated, and the tilt angle of the reflecting mirror is output to the reflecting mirror tilting mechanism based on this mounting error.

In the optical axis adjusting device according to the second aspect of the present invention, the light spot displacement information is read from the light spot displacement detection mechanism, and an error occurs in the light spot displacement only due to the mounting error of one reflecting mirror. Assumed, calculate the approximate mounting error of the reflector,
Based on this mounting error, the tilt angle of the reflecting mirror is output to the reflecting mirror tilting mechanism.

[0011]

In the optical axis adjusting device according to the first aspect of the present invention, the light spot displacement detecting mechanism for detecting the two-dimensional displacement of the light spot from the center of one reflecting mirror to the photoreceptor through the other reflecting mirror is read. The mounting error of the reflecting mirror is calculated from the light spot displacement information and the axial displacement information indicating the displacement of the central axis between the reflecting mirrors read from the axial displacement detecting mechanism, and the tilt angle of the reflecting mirror is calculated based on this mounting error. By providing the optical axis adjusting mechanism for outputting to the tilting mechanism, it becomes possible to automatically correct the mounting error of the reflecting mirror.

The optical axis adjusting device according to the invention of claim 2 is
Light spot displacement information is read from a light spot displacement detection mechanism that detects the two-dimensional displacement of the light spot on the light receiver on the light receiver from the center of one reflector to the light receiver through the other reflector, and one of the reflections is read. It is considered that there is an error in the light spot displacement due to the mirror mounting error only, and an approximate mounting error of the reflecting mirror is calculated, and the tilt angle of the reflecting mirror is output to the reflecting mirror tilting mechanism based on this mounting error. By providing the optical axis adjustment mechanism to
It becomes possible to automatically correct the approximate mounting error of the reflecting mirror.

[0013]

【Example】

Example 1. An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram showing an optical axis adjusting device according to an embodiment of the present invention. In the figure, the same reference numerals as those of the conventional one indicate the same or corresponding portions, and therefore the description thereof will be omitted. The part surrounded by the one-dot chain line is a constituent element of the conventional optical axis adjusting device, and the part outside the one-dot chain line is a constituent element relating to the optical axis adjusting device of the present invention.

Reference numeral 11 denotes a reflecting mirror which is tiltably supported by a reflecting mirror support mechanism (eg, gimbal mechanism) 12.
Reference numeral 3 denotes a reflecting mirror tilting mechanism capable of tilting the reflecting mirror 11 in the left-right direction with respect to the inner frame and in the up-down direction (hereinafter, referred to as 2 degrees of freedom) with respect to the outer frame. It is composed of a micrometer (not shown) for tilting by pushing from the back side, a motor (not shown) for driving it, an encoder (not shown) for detecting its rotation, and the like. A mechanical axis 14 indicates a central axis between the reflecting mirrors 11 in the laser robot or the direct-acting laser beam machine, and includes a rotary axis or a direct-acting axis. Reference numeral 15 denotes a shaft drive mechanism that drives the mechanical shaft 14, and is composed of, for example, a motor, a speed reducer, and a ball screw. Note that these components are not shown.

Reference numeral 16 denotes a shaft displacement detecting mechanism for detecting the displacement of the mechanical shaft 14, which is composed of, for example, an encoder for detecting the rotation angle of the motor of the mechanical shaft 14. Reference numeral 17 denotes an axis control mechanism that controls the machine axis 14 in accordance with a command from a controller (not shown) of the laser processing machine. Reference numeral 18 denotes a light spot displacement detection mechanism that detects the two-dimensional displacement of the light spot irradiated on the light receiving body. For example, a PS that converts the position of the light spot into a voltage
D (amplifier, A / D converter, etc.).
Reference numeral 19 denotes an optical axis adjusting mechanism, which uses the information on the axial displacement obtained from the axis control mechanism 17 and the information on the optical point displacement obtained from the optical point displacement detecting mechanism 18 to perform coordinate conversion calculation to tilt the reflecting mirror 11. The displacement is calculated and information on the tilt displacement is transmitted to the reflecting mirror tilt mechanism 13. Although the reflecting mirror tilting mechanism 13 is driven by the motor, it may be manually driven according to the tilting displacement of the optical axis adjusting mechanism 19.

Next, a detailed adjustment procedure of the optical axis adjusting mechanism 19 will be described. FIG. 2 is a block diagram showing an optical system model of an optical axis adjusting device according to an embodiment of the present invention.
Reference numerals 11a and 11b are the reflecting mirrors shown in FIG. 1, and 20 is a light receiving body of the light spot displacement detecting mechanism 18.

Main vectors will be described with reference to FIG. M _j : a unit normal vector (j = 1, 2) standing on the entrance / reflection side of the reflecting mirrors 11a and 11b. C _j : Position vector of the center of the reflecting mirrors 11a and 11b or the light receiver 20 (j = 1, 2, 3). L _j : unit optical axis vector (j
= 0), or the unit optical axis vector (j = 1, 2) reflected from the reflecting mirrors 11a and 11b. Gθp: Two-dimensional coordinates of the light spot detected on the photoconductor 20. N ₁ : A unit vector between the reflecting mirrors 11a and 11b in the optical axis from the center of the reflecting mirror 11a to the center of the approximate circle on the photoreceptor when θ = 0. N _2: via the reflector 11b from the center of the reflecting mirror 11a when theta = 0, among the light axis extending in the center of the approximate circle on the photoreceptor 20, the reflecting mirror 11b, unit vectors between the photoreceptor 20. Op: Two-dimensional coordinates (x
₀ , y ₀ ) ^T. O: Three-dimensional coordinates of the center of the approximate circle on the photoreceptor 20.

A coordinate transformation matrix that rotates the vector v about the ω axis by θ is expressed as E (ωθ) v. The component of the vector v is expressed as (vx, vy, vz) ^T. Here, T represents the transposition of the vector. Two 3D coordinates "v"
The one expressed in the dimensional coordinate is added with p to be “vp”.

In FIG. 2, the reflecting mirrors 11a and 11b are vertically installed from the correct mounting posture by δ _a1 and δ _a2 , and left and right by δ _b1 and δ.
_With an angular error of _b2 , the center is the machine axis (l ₀ , l ₁ , l
_It should coincide with the intersection of ₂ ). The incident optical axis is parallel to the mechanical axis l ₀ and strikes the center of the reflecting mirror 11a. The normal line standing at the tip of the emission side coincides with the mechanical axis l ₂ . Further, in the base coordinate system Σ0, the rotation axis direction is x and the upper side is z. The rotation axis displacement is represented by θ. The base coordinate system Σ0 is an absolute coordinate system, in which the rotation axis of the modeled optical system is parallel to the X axis of the absolute coordinate system and the upper side of the optical system is aligned with the Z axis.

When the rotation axis rotates about the mechanical axis l ₀ , the locus of the light spot draws a circle, so the coordinates and radius of the center of this circle are obtained. If the three points passing through the circle are known, the coordinates and radius of the center of the circle can be known. 2 of the light spots detected on the photoreceptor 20
The three-dimensional coordinates are set to G0p, G1p, and G2p (these are, for example, θ = 0, −π / 2, π for the angles θ of the rotation axes, respectively).
/ 2, etc.), the coordinates of the center of the approximate circle on the photoconductor 20 are Op (x ₀ , y ₀ ) ^T , and the radius is r, the following formula is established. (G0p-Op) · (G0p -Op) = r 2 (G1p-Op) · (G1p-Op) = r 2 (G2p-Op) · (G2p-Op) = r 2 (1) It should be noted that, "-" Represents the dot product of the vector, which is Op (x
₀ , y ₀ ) and r.

Next, the method of obtaining the vector of the reflecting mirror 11a and the mounting error will be described in four steps in order. In this case, it is necessary to classify the light spots according to the phase on the approximate circle of the coordinates.

Step 1 First, it is checked whether the coordinate G0p of the light spot on the photoconductor 20 when the angle θ of the rotation axis is 0 is in the quadrant of the approximate circle in the xy coordinate system on the photoconductor 20. . Therefore, the coordinate of the light spot when θ slightly increases from G0p is Gdp. G0
The x and y coordinates of p and Gdp are (x _g0 , y _g0 ) ^T , respectively.
_Given (x _gd , y _gd ) ^T , the following cases can be classified based on their magnitude relations. 1st quadrant x _g0 > x _gd & y _g0 <y _gd 2nd quadrant x _g0 > x _gd & y _g0 > y _gd 3rd quadrant x _g0 <x _gd & y _g0 > y _gd 4th quadrant x _g0 <x _gd & Y _g0 <y _gd

Step 2 Next, the rotation axis is rotated in the positive direction from G0p, and the angle θ _a when the light spot first comes on the x-axis or the y-axis of the photoreceptor 20.
To measure. The coordinates of the light spot when G0p comes on the axis from the quadrant examined in step 1 are the coordinates Op of the center of the approximate circle.
Using (x ₀ , y ₀ ) ^T and the radius r, the following is obtained for each quadrant case. The first quadrant _{(x 0, y 0 + r} ) T second quadrant _{(x 0 -r, y 0)} T third quadrant _{(x 0, y 0 -r)} T the fourth quadrant _{(x 0 + r, y 0} ) T However, these coordinates are approximate values. Therefore, to determine that the light spot is on the axis, for example, a change in the extreme value of the coordinates of the light spot when the rotation shaft is rotated may be detected as follows. First quadrant y coordinate is maximum Second quadrant x coordinate is minimum Third quadrant y coordinate is minimum Fourth quadrant x coordinate is maximum

Step 3 When θ = 0, from the center of the reflecting mirror 11a to the reflecting mirror 11
The mechanical axis l _{1 of the} optical axis reaching the light spot on the photoreceptor 20 via b
The angles δ _y and δ _z with respect to are obtained. The radius r of the approximate circle obtained in step 1 and the angle θ _a when the light spot obtained in step 2 comes on the axis are used. δ _y and δ _z are angles around the y axis and the z axis of the base coordinate system Σ ₀ , respectively. These are as follows for each quadrant of the approximate circle. First quadrant δ _y = -r sin θ _a / (l ₁ + l ₂ ) δ _z = r cos θ _a / (l ₁ + l ₂ ) Second quadrant δ _y = r cos θ _a / (l ₁ + l ₂ ) δ _z = r sin θ _a / (l ₁ + l ₂ ) 3rd quadrant δ _y = r sin θ _a / (l ₁ + l ₂ ) δ _z = −r cos θ _a / (l ₁ + l ₂ ) 4th quadrant δ _y = −r cos θ _a / (L ₁ + l ₂ ) δ _z = −r sin θ _a / (l ₁ + l ₂ ) (2)

Step 4 The vectors of the reflecting mirrors 11a and 11b are obtained from the vectors of the reflecting mirrors 11a and 11b and the incident / reflected light. Using δ _y and δ _z obtained in step 3, θ = 0
At this time, the vector L _{1 of the} optical axis from the center of the reflecting mirror 11a to the reflecting mirror 11b is as follows. L ₁ = E (k (dz)) E (j (dy)) i (3) where i is a unit vector in the x-axis direction. The relationship between L ₁ and the vector L _{0 of} light incident on the reflecting mirror 11a and the vector M ₁ of the reflecting mirror 11a is as follows. _{L 1 = L 0 -2 (L} 0 · M 1) M 1 (4) (3) by substituting equation in (4), solving for M _1. Next, in order to convert M ₁ into a mounting error of the reflecting mirror, M ₁ is rotated around the y-axis of the base coordinate system Σ ₀ to match the x-axis. M _1a = E (j (−π / 4)) M ₁ (5) The y and z coordinates of M _{1a in} the equation (5) are m _1ay and m _1az , respectively.
In other words, the mounting error (δ _a1 , δ _b1 ) ^T of the reflecting mirror 11a is as follows. δ _a1 = -m _1az δ _b1 = m _1ay (6)

Next, a method of obtaining the vector of the reflecting mirror 11b and the mounting error will be described. A three-dimensional vector O in which the two-dimensional coordinate Op (x ₀ , y ₀ ) ^T of the center of the approximate circle on the photoreceptor is viewed from the base coordinate system Σ0 is O = C ₃ + (x ₀ , y ₀ , 0) ^T ( 7)

The vector N ₁ from the center of the reflecting mirror 11a to the center of the reflecting mirror 11b and the vector N ₂ from the center of the reflecting mirror 11b to the center of the approximate circle are N ₁ = C ₂ -C ₁ (8) N ₂ = the O-C ₂ (9). The relationship between N ₁ and N ₂ and the vector M ₂ of the reflecting mirror 11b is N ₂ = N ₁ -2 (N ₁ · M ₂ ) M ₂ (10). The equations (7), (8) and (9) are substituted into the equation (10) to solve for M ₂ .

[0028] M ₂ reflectors 11a, for converting the mounting error of 11b, by rotating the M ₂ about the y-axis of the base coordinate system sigma ₀ match the z-axis. M _2a = E (j (π / 4)) M ₂ (11) If the x and y coordinates of M _2a are m _2ax and m _2ay , respectively,
The mounting errors (δ _a2 , δ _b2 ) of the reflecting mirror 11b are as follows. δ _a2 = m _2ax δ _b2 = −m _2ay (12)

As described above, according to the first embodiment, the optical axis can be automatically adjusted when the laser robot is assembled or adjusted after the assembly. Moreover, since it is not necessary to manufacture an optical system such as an image processing device and a beam splitter, the cost can be reduced.

Example 2. Next, the case of the direct drive shaft will be described with reference to FIGS. FIG. 3 is a configuration diagram showing a model of an optical axis adjusting device for a linear axis according to an embodiment of the present invention. In the figure, the same reference numerals as those of the conventional one indicate the same or corresponding portions, and thus the description thereof will be omitted. 21a,
Reference numeral 21b is a reflecting mirror which is linearly driven along the mechanical axis l ₁ . Since the configuration of the optical axis adjusting device is the same as that of the first embodiment, its description is omitted.

First, similarly to the case of the rotation axis, the length s of the line segment drawn by the light spot on the light receiving body 20 and the angle φ are obtained. The two-dimensional coordinates of the light spot detected on the photoreceptor when the displacement of the linear axis is x _min and x _max are G0p and G1p, respectively. At this time, the length s of the line segment and the angle φ are as follows. s = ((G0p-G1p) ・ (G0p-G1p)) ^1/2 (13) cos φ = (G0x-G1x) / s sin φ = (G0y-G1y) / s (14) where “·” is a vector Indicates the dot product.

Next, the method of obtaining the vector of the reflecting mirror 21a and the mounting error will be described. The angle of the vector L ₁ of the reflected light from the reflecting mirror 21a with respect to the mechanical axis l ₁ can be calculated by using equations (13) and (14) as follows: dx = −tan ⁻¹ (s / x _st sinφ) dy = tan ⁻¹ (s / x _st cosφ) (15) Here are the stroke x _st direct drive shafts and _{x st = x max -x min (} 16).

Using dx and dy in the equation (15) and the unit vector i on the x-axis, L ₁ is L ₁ = E (k (-dz)) E (j (-dy)) i (17) Become.

As in the first embodiment, L ₀ and (1
By substituting the equation 7) and solving for M ₁ , the vector of the reflecting mirror 21a can be obtained. However, sin φ ≠ 0.

When sin φ = 0, the y component is 0, so
If two-dimensional vectors corresponding to M ₁ , L ₀ , and L ₁ are represented with p respectively, the following is obtained. M ₁ p = (m _1x , m _1z ) ^T (18) L ₀ p = (0,1) ^T (19) L ₁ p = (L _1x , L _1z ) ^T (20) Using these (17) The formula is as follows. L ₁ p = L ₀ p−2 (L ₀ p · M ₁ p) M ₁ p (21) If this equation (21) is solved for M ₁ p, the reflecting mirror 11 a
M ₁ = (m _1X , 0, m _1Z ) ^T (22) is obtained by using the vector M ₁ of M ₁ p.

The solution of equation (4) obtained above or (22)
Substituting M ₁ of the equation into the equation (5) of the first embodiment, the first embodiment
From equation (6), the mounting errors δ _a1 and δ _{b1 of the} reflecting mirror 21a can be obtained.

Next, a method of obtaining the vector of the reflecting mirror 21b and the mounting error will be described. If the radius x of the approximate circle on the photoconductor 20 is r when the displacement of the linear axis is x = x _max , then r = (l ₁ + l ₂ ) s / x _st (23). The two-dimensional coordinate Op of the center of the approximate circle is Op = G0p− (r cos φ, r sin φ) ^T (24) when r is used.

The position vectors of the centers of the reflecting mirror 21b and the photoreceptor 20 are as follows. _{C 1 = (0,0, l 0} ) T (25) C 2 = C 1 + (l 1, 0,0) T (26) C 3 = C 2 + (0,0, l 2) T (27 )

Using the x and y elements of the equation (24) and the equation (27), the three-dimensional coordinate O of the center of the approximate circle is O = C ₃ + (Opx, Opy, 0) ^T (28) .

Similar to the first embodiment, by substituting the equations (25) to (28) into the equations (8) and (9), the vectors N ₁ and N ₂ can be obtained. By substituting these into the equation (10) and solving for M ₂ , the vector of the reflecting mirror 21b is obtained. By substituting M ₂ into the equation (11), the mounting errors δ _a2 and δ _{b2 of the} reflecting mirror 21b can be obtained from the equation (12).

As described above, according to the second embodiment, the same effect as that of the first embodiment can be obtained, and it can be applied to the direct-acting laser processing machine.

Example 3. The third embodiment is the same as the first and second embodiments except that it does not have a rotary shaft or a linear motion shaft. FIG. 4 is a configuration diagram showing an optical axis adjusting device according to another embodiment of the present invention, and FIG. 5 is a configuration diagram showing an optical system model of the optical axis adjusting device according to another embodiment of the present invention. In the figure, the same reference numerals as those of the conventional one indicate the same or corresponding portions, and thus the description thereof will be omitted. Reference numeral 22 denotes an optical axis adjusting mechanism, which uses the information on the light spot displacement obtained from the light spot displacement detecting mechanism 18 to perform a coordinate conversion operation to reflect the light from the reflecting mirror 1 on the base side.
An approximate value of the tilting displacement of 1 is calculated, and information on the tilting displacement is transmitted to the reflecting mirror tilting mechanism 13.

Next, the procedure for adjusting the optical axis adjusting mechanism 22 will be described with reference to FIG. First, let the coordinates of the light spot on the photoreceptor be (x,
y), if an approximate circle of the light spot is considered in the same manner as in Example 1,
The phase θ _a of the light spot is represented by the following equation using the radius r of the approximate circle. cos θ _a = x / r sin θ _a = y / r (29)

Considering the mounting error of the reflecting mirror 11b as 0,
From the center of the reflecting mirror 11a, through the reflecting mirror 11b, to the photoreceptor 2
The angle δ of the optical axis reaching the light spot on 0 with respect to the mechanical axis l ₁ .
_{Find y} and δ _z . At this time, the radius r of the approximate circle and the phase θ _a of the light spot are used. δ _y and δ _z are angles around the y axis and the z axis of the base coordinate system Σ0, respectively. δ _y = -r cos θ _a / (l ₁ + l ₂ ) δ _z = r sin θ _a / (l ₁ + l ₂ ) (30)

Using δy and δz, the vector L _{1 of the} optical axis from the center of the reflecting mirror 11a to the reflecting mirror 11b is as follows. L ₁ = E (k (dz)) E (j (dy)) i (31) where i is a unit vector in the x-axis direction.

Next, the vector of the reflecting mirrors is obtained from the reflecting mirrors 11a and 11b and the vector of the incident / reflected light. The relationship between L ₁ and the vector L _{0 of} light incident on the reflecting mirror 11a and the vector M ₁ of the reflecting mirror 11a is as follows. _{L 1 = L 0 -2 (L} 0 · M 1) M 1 (32) (32) Equation solving for M _1.

In order to convert M ₁ into the mounting error of the reflecting mirror,
Rotate M ₁ around the y-axis of the base coordinate system Σ0 to match the x-axis. M _1a = E (j (−π / 4)) M ₁ (33) The y and z coordinates of M _{1a in} the equation (33) are m _1ay and m, respectively.
If you _{say 1az} , the mounting error of the reflector 11a (δ _a1 , δ _b1 )
Each ^T is as follows. δ _a1 = -m _1az δ _b1 = m _1ay (34)

The optical path length from the reflecting mirror 11a to the light receiving body 20 is l ₁ + l ₂ , while the light path from the reflecting mirror 11b to the light receiving body 2 is 1.
The optical path length to 0 is l ₂ . Therefore, when the mounting errors of the reflecting mirror 11a and the reflecting mirror 11b are of the same order of magnitude, the mounting error has a greater effect on the error of the light spot viewed from the light receiving body 20 in the reflecting mirror 11a. Therefore, the mounting error of the entire optical system can be represented by δ _a1 and δ _b1 in the equation (6).

As described above, according to the third embodiment, the optical axis can be automatically adjusted at the time of assembling the laser robot and the direct-acting laser processing machine or at the time of adjusting after the assembly. Moreover, since it is not necessary to manufacture an optical system such as an image processing device and a beam splitter, the cost can be reduced.

The above effect becomes more remarkable as l ₁ is larger than l ₂ . Therefore, when designing the laser processing machine, it is preferable to design l ₁ to be larger than l ₂ . Further, although the above embodiments have been described with respect to one axis, respectively, by combining the above methods and independently operating each axis, it is possible to apply to a laser processing machine having a plurality of axes. Further, it is also possible to apply to a laser processing machine in which a rotary shaft and a linear motion shaft are mixed.

Furthermore, in the above-mentioned embodiments, the case where the present invention is applied to the adjustment of the optical axis of the laser beam machine is described, but it is also possible to apply to other optical systems having a reflecting mirror and a driven axis, for example, a periscope. Has a great effect.

[0052]

As described above, according to the first aspect of the invention, the mounting error of the reflecting mirror is calculated from the light spot displacement information read by the light spot displacement detecting mechanism, and the reflecting mirror mounting error is calculated based on this mounting error. Since the tilt angle is output to the tilting mechanism of the reflecting mirror, the optical axis can be automatically adjusted at the time of assembling the laser robot and the direct-acting laser processing machine or at the time of adjustment after the assembly. There is an effect that the cost can be reduced and the invention can be applied to a direct-acting laser processing machine.

According to the second aspect of the present invention, the light spot displacement information is read from the light spot displacement detection mechanism, and it is considered that an error has occurred in the light spot displacement only due to the mounting error of one of the reflecting mirrors. Is calculated, and the tilt angle of the reflecting mirror is output to the reflecting mirror tilting mechanism based on this mounting error, so that the laser robot and the direct-acting laser processing machine are assembled or assembled. The optical axis can be automatically adjusted at the time of the subsequent adjustment, and the cost can be reduced, and it can be applied to the direct-acting laser processing machine.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an optical axis adjusting device according to an embodiment of the present invention.

FIG. 2 is a configuration diagram showing an optical system model of an optical axis adjusting device according to an embodiment of the present invention.

FIG. 3 is a configuration diagram showing a model of an optical axis adjusting device for a linear axis according to an embodiment of the present invention.

FIG. 4 is a configuration diagram showing an optical axis adjusting device according to another embodiment of the present invention.

FIG. 5 is a configuration diagram showing an optical system model of an optical axis adjusting device according to another embodiment of the present invention.

FIG. 6 is a configuration diagram showing a conventional optical axis adjusting device disclosed in, for example, Japanese Patent Laid-Open No. 5-329674.

[Explanation of symbols]

11a, 11b, 21a, 21b Reflecting mirror, 13 Reflecting mirror tilting mechanism, 16 Axis displacement detecting mechanism, 18 Light spot displacement detecting mechanism, 19, 22 Optical axis adjusting mechanism, 20 Photoreceptor.

Claims (2)

[Claims] 1. An optical axis adjusting device having a reflecting mirror tilting mechanism for changing the tilting angle of a pair of reflecting mirrors for changing the optical path of a laser beam emitted from a laser oscillator. Displacement detection mechanism for detecting the displacement of the laser beam, and a light spot displacement detection mechanism for detecting the two-dimensional displacement of the light spot on the photoconductor of the laser light from the center of one reflecting mirror to the photoconductor via the other reflecting mirror. Then, the mounting error of the reflecting mirror is calculated from the light spot displacement information read by the light spot displacement detecting mechanism and the axial displacement information read by the axial displacement detecting mechanism, and the inclination of the reflecting mirror is calculated based on the mounting error. An optical axis adjusting device comprising an optical axis adjusting mechanism for outputting an angle to the reflecting mirror tilting mechanism. 2. An optical axis adjusting device having a reflecting mirror tilting mechanism for changing a tilting angle of a pair of reflecting mirrors for changing an optical path of a laser beam emitted from a laser oscillator. A light spot displacement detection mechanism for detecting a two-dimensional displacement of a light spot on the light receiver on the light receiver passing through the other reflecting mirror and a light spot, and reading the light spot displacement information from the light spot displacement detection mechanism. It is considered that there is an error in the displacement of the light point only due to the mounting error of the reflecting mirror, an approximate mounting error of the reflecting mirror is calculated, and the tilt angle of the reflecting mirror is calculated based on the mounting error. An optical axis adjusting device, comprising: an optical axis adjusting mechanism for outputting to a reflecting mirror tilting mechanism.