JPS62144006A - Method for generating multislit light - Google Patents

Abstract

PURPOSE:To make it possible to also generate a slit light source coming to a reference value by one multislit light source, by changing over multislit light and single slit light due to a cylindrical lens and two diffraction lattices of which the diffraction directions cross at a right angle according to a time sharing system by controlling a shutter. CONSTITUTION:The light from LD being a light source is collimated and formed into multislit light sources l1-l4 by a cylindrical lens 9 and diffraction lattices A, B of which the diffraction directions are orthogonal and parallel to the axis of the lens 9. When an electronic shutter 10 is controlled, the light sources other than the light source l3 coming to a reference value are blocked and the slit light source l3 coming to the reference value can be generated according to a time sharing system by one multislit light source.

Description

[Detailed Description of the Invention] [Summary] By arranging two diffraction gratings whose diffraction directions are orthogonal to each other and a cylindrical lens whose axial direction is parallel to the diffraction direction of one diffraction grating, on the optical axis of parallel light. By providing a shutter that generates multi-slit light and blocking light other than a specific slit light, and controlling the shutter,
By time-divisionally switching between multi-slit light and single-slit light, one multi-slit light source can also generate basic slit light.

[Industrial application field]

In industrial robots, when objects are measured and controlled three-dimensionally, a multi-slip I/light source that can measure multiple points simultaneously is an effective method to shorten measurement time. sexuality is increasing. The present invention
The present invention relates to a method for generating multi-thrino I light that can be used in such applications.

(Prior Art) Fig. 4 is a perspective view showing a three-dimensional measurement method of an object using a multi-slit light source proposed by the applicant of the present invention as Japanese Patent Application No. 107675/1983. Slit light generated by multi-slit light source 2 on object 1! ! 1.122... is irradiated, and the intersection of each slit light J21, 12... and the object 1 is photographed with the camera 3. At this time, the slit light e1.22... and the projection point P1,
It is necessary to associate P2... with. For this purpose, a separate slit light source 4 is used to generate one reference slit light 5.

By arranging the reference slit light 5 of the slit light source 4 so that it exactly coincides with one slit light surface of the multi-slit light source 2, it is possible to solve the problem of correspondence when using a multi-slit light source, which has been considered difficult in the past. We are trying to solve this problem.

This is the slit light 1 generated by the multi-slit light a2.
1.12... is because the brightness is almost the same. Figures 5 and 6 are made by the applicant of the present invention
FIG. 2 is an exploded perspective view showing a conventional multi-slit light source proposed as No. 2. In FIG. 5, light l1i of parallel light 6
A cylindrical lens 9, a diffraction grating A whose diffraction direction is perpendicular to the axial direction of the cylindrical lens 9, and a diffraction grating B whose diffraction direction is parallel to the axial direction of the cylindrical lens 9 are arranged on the TII 8. The parallel light 6 is a semiconductor laser L
It is created by converting single-wavelength diverging light emitted from a light emitting diode or the like into parallel light using the collimating lens 7. The cross section of the parallel light 6 becomes a perfect circular light spot S, but when the parallel light passes through the cylindrical lens 9, it is expanded in the direction perpendicular to the axial direction of the cylindrical lens 9, and becomes an elliptical spot S like Sa. Become a spot. Then, when it passes through the diffraction grating A and is diffracted, the cylindrical lens 9
(Multiple ellipsoids in the direction perpendicular to the axis direction (X direction))
Sal, Sa2, . . . are generated in a dispersed manner, and the ends of adjacent oval spots overlap to form one slit light l. When this slit light i passes through the next diffraction grating B and is diffracted, a plurality of slit lights p1, β2, . . . are generated in the axial direction (X direction) of the cylindrical lens 9 and are multiplied. It is assumed that the area of the diffraction grating portions of the two diffraction gratings A and B is large enough to allow sufficient irradiation of incident light.

The slit lights 11, i2, . . . in FIG. 4 are generated in this manner. In FIG. 6, the positions of two diffraction gratings A and B are exchanged. Therefore, the oval light spot Sa emitted from the cylindrical lens 9
is diffracted in the axial direction (X direction) of the cylindrical lens 9, and a plurality of oval subonotations t-3xl, Sx2...
Occurs in 1. Next, these oval subbos 71・sxl
, Sx2... in the X direction by the diffraction grating A, a plurality of oval spots are generated dispersedly in the X direction as well, and the ends of the adjacent oval spots overlap, so that a plurality of oval spots are generated. Slit light p1. x2... and naro.

The cylindrical lens 9 has two diffraction gratings A and I.
The same effect can be obtained even if it is placed after or before 3, or in the middle.

[Problem that the invention seeks to solve]

In such a conventional method, the brightness of the slit lights 11, 12... is highest at the part on the optical axis 8 and gradually becomes darker toward the periphery, so that the brightness of the slit lights 11, 12... To distinguish only slit light, two slit light sources 2.
Requires 4. Moreover, it is difficult to align the slit beams to overlap each other.

The technical problem of the present invention is to solve such problems when performing three-dimensional measurement using a conventional multi-slit light source.
- It is also possible to generate light.

[Means for solving problems]

FIG. 1 is an exploded perspective view illustrating the basic principle of the method for generating multi-slit light according to the present invention. The means for obtaining the slit beams 7!1, p2, etc. is the same as the conventional one.Therefore, on the optical axis 8 of the parallel beam 6 of a single wavelength, there are two diffraction gratings A and B whose diffraction directions are orthogonal to each other, and the axis By arranging the cylindrical lens 9 whose direction is parallel to the diffraction direction of one diffraction grating B, a plurality of slit lights 11, 12...
The configuration is such that this occurs.

In the present invention, a shutter means 10 is provided in front of each of these slit lights 11, 12, . . . to block out lights other than one specific slit light. As shown in FIG. 6, a diffraction grating B whose diffraction direction is parallel to the axial direction of the cylindrical lens 9, and an elliptical spot light Sxl dispersed in the axial direction,
The shutter means 10 may be placed immediately before Sx2....

By controlling this shutter means 10, it is time-divisionally switched between single slit light and multi-slit light.

[Effect]

As explained in FIG. 5, the cylindrical lens 9 and the two diffraction gratings A arranged on the optical axis 8 of the parallel light 6
, B, a plurality of slit lights a1, 12, . . . are obtained by the parallel light 6 passing through them.

In the present invention, the shutter means 10 is arranged in front of this slit light ρ1, 12..., but since there is no shutter means 10 in front of one specific slit light, for example 13, this slit light 13 is Means 10 on/off
It always occurs regardless of off operation. However, (b
1, when the shutter means 10 operates and enters the shielding state, all but the specific slit light 13 are blocked,
Only one slit beam β3 is obtained. fa), when the shutter means 10 is turned off and enters the non-shielding state, the shutter means 10 enters the transmittable state, so that all the slit lights 21, β2, . . . are obtained and become multi-slit light. Therefore, when the shack means 10 is controlled on and off, only one slit beam 13 is generated in the on state, and multi-slit beams 11, β2, . . . are generated in the off state.

〔Example〕

Next, how the method for generating multi-slit light according to the present invention is actually implemented will be explained using examples. FIG. 2 is an exploded perspective view showing an embodiment of the present invention. On the optical axis 8, there is a semiconductor laser LD that generates a single wavelength laser beam, a collimating lens 7, a cylindrical lens 9, and the diffraction direction is the same as that of the cylindrical lens. A diffraction grating B parallel to the axial direction of the diffraction grating 9, a shutter 10, and a diffraction grating A having a diffraction direction perpendicular to the diffraction grating B are arranged in this order. Therefore, the sixth
As in the case shown in the figure, the diverging light emitted from the semiconductor laser LD is converted into parallel light 6 by the collimating lens 7, and then is expanded in the y-axis direction by passing through the cylindrical lens 9, resulting in an elliptical light spot. It becomes Sa. When this light having an elliptical cross section is transmitted through the diffraction grating B and diffracted in the X-axis direction, dispersed lights Sxl, Sx2, etc. having an elliptical cross section are generated.

and distributed spots Sxl, Sx2 and Sx4, Sx
Since there is a shutter 10 in front of 5, the shutter 10
is turned on and enters the shielding state, the spot Sx on the optical axis 8
Only 3 can pass through the shutter 10. Since only the spora h Sx3 is diffracted and dispersed in the y-axis direction by the next diffraction grating A, one slit beam 13 is finally obtained.

When the shutter 10 is turned off and the shielding becomes impossible,
Spot Sxl separated by 11 minutes in the X-axis direction on diffraction grating B
, Sx2, .

In FIGS. 5 and 6, the brightness of the slit lights 11, 12... is the light 11i! The area above IIB is the highest, and it gradually becomes darker toward the periphery, but in the present invention, when the shutter 10 is turned on and the rg qffi state is reached, the light Φ'
Since only one slit light 23 on 118 is generated, one multi-slit light source can also simultaneously generate the slit light 5, which is the reference in FIG.

Moreover, the slit light of Ki4jin is 7!3, and the slit light is 11.4.
Since it is one of the backs of 2..., there is no need for positioning operations.

In this embodiment, the shutter 10 is placed between the diffraction grating B, but it may be placed before the last diffraction grating A. As is clear from FIGS. 1 and 2, the diffraction gratings A and B may be reversed in position. Further, the cylindrical lens 9 may also be arranged between both the diffraction gratings A and B, or at the very front.

When disposed at the forefront, if the distance between them is increased, the upper and lower ends of the slit light may be cut off depending on the size of the cylindrical lens 9, so it is necessary to arrange them as close as possible.

(Example of one shank means) Examples of the shutter means 10 include an electronic shutter without mechanical movement and a movable shutter that opens and closes mechanically. Electronic shutters include those that use liquid crystal that utilizes polarized light, and those that use a piezoelectric material made from four components of titanium, zircon, lead, and lanthanum between two polarizing plates, and change the polarization plane by turning on and off the voltage. It is possible to use a material sandwiched with a material called PLZT, which has a variable temperature. Electronic shutters have a configuration in which two electronic shutters are arranged at a distance as shown in Figures 1 and 2, as well as a configuration in which one electronic shutter has a reference slit as shown in Figure 3 (al). It is also possible to have a configuration in which the gap 11 is opened only at the light area.

In addition, in the case of a mechanical shutter, using the A shielding plate 13 shown in FIG. 3 (as shown in BL, the aperture 12 that allows only the reference slit light to pass through) is used, and the multi-slit light 11, β2...
To obtain this, the shielding plate 13 is retracted, and to obtain only one reference slit beam, the shielding plate 13 is moved onto the optical axis 8, so that only one slit beam can pass through the aperture 12. shall be.

〔others〕

Although a semi-cylindrical lens is shown as an example of the cylindrical lens 9, any anisotropic lens that has an oval or long cross section and can generate light in the same way as the cylindrical lens 9 can be used under the concept of a cylindrical lens. shall be included. For example, the same effect can be obtained by creating a hologram by irradiating a hologram recording medium with parallel light from one side and convergent light with a long cross section from the other side.

As the diffraction gratings A and B, a fiber array made up of several dozen optical fibers arranged in parallel is suitable, but other diffraction gratings may be used.

[Effects of the Invention] As described above, according to the present invention, single slit light and multi-slit light can be obtained by time-divisionally switching with one multi-slit light source. Therefore, there is no need to provide a light source exclusively for the reference slit light as in the past, and there is no need to align the slit lights so that they overlap each other, which simplifies mounting.

[Brief explanation of drawings]

Fig. 1 is an exploded perspective view illustrating the basic principle of the multi-slit light generation method according to the present invention, Fig. 2 is an exploded perspective view showing an embodiment of the method of the present invention, and Fig. 3 is an embodiment of a shack unit. FIG. 4 is a perspective view showing a three-dimensional measurement method using multi-slit light, and FIGS. 5 and 6 are exploded perspective views showing a conventional method for generating multi-slit light. In the figure, 6 is parallel light, 7 is a collimating lens, 8 is an optical axis, 9 is a cylindrical lens, A is a diffraction grating whose diffraction direction is at an angle M with the axial direction of the cylindrical lens, and B is a diffraction direction whose diffraction direction is along the axial direction of the cylindrical lens. 10 is a shutter (means), 11 is a slit, 12 is an aperture, LD is a semiconductor laser, Sxl, Sx2... are light spots, and 11, β2... are slit lights, respectively.

Claims (1)

[Claims] Two diffraction gratings (A) and (B) whose diffraction directions are orthogonal to each other and one diffraction grating ( A cylindrical lens (9) parallel to the diffraction direction of B) is arranged, and the parallel light (6) passes through each of these elements to form a plurality of slit lights (11),
(12) A plurality of slit lights (l1) dispersed in the axial direction of the cylindrical lens (9), with the diffraction direction in front of the diffraction grating (B) in the axial direction of the cylindrical lens (9), (l2
)... or spot light (Sx1) (Sx2)... by providing a shutter means for blocking all but a specific one of them, and controlling the shutter means to time-share the single slit light and the multi-slit light. A method for generating multi-slit light characterized by switching between the two.