JPS61149919A - slit light source - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a slit light source used as a structural illumination device in three-dimensional measurement, distance image generation, etc. using a light cutting method.

[Prior art]

FIG. 2 is a diagram for explaining the first conventional slit light source.

In Fig. 2, ■ is a high-intensity lamp, 2 is a slit plate with a slit 2a in the center, and 3 is a lens for converting the slit light obtained by the slit plate 2 into slit light 3 with a predetermined length l. be.

Note that the high-intensity lamp 1, slit plate 2, and lens 3 are arranged so that their respective centers coincide with the Z-axis direction.

FIG. 3 is a diagram for explaining a second conventional slit light source.

In FIG. 3, 4 is a laser diode, 5 is a collimating lens for converting the diverging light emitted from the laser diode 4 into circular parallel light, and 6 is a collimating lens 5.
This is a cylindrical lens for converting parallel light made into parallel light into an elongated elliptical spot light 6a.

Note that, similarly to FIG. 2, each member is arranged so that its center coincides with the Z-axis direction.

[Problem that the invention seeks to solve]

In general, three-dimensional measurement or distance image generation using a light cutting method requires a slit light with a sufficient length to traverse the screen.

However, in the conventional slit light source explained using FIGS. 2 and 3, the length of the slit light is determined by the focal length of the lens 3 and the cylindrical lens 6. In order to obtain this, it is necessary to construct a lens system with a short focal length, which poses a problem in that the cost of the device becomes significantly high.

In addition, the slit light emitted from a lens system with a short focal length has the problem that the brightness distribution of the light source is directly reflected in the slit light, so the brightness is extremely high near the optical axis, and the brightness decreases rapidly toward the periphery. was there.

[Means for solving problems]

In view of the above-mentioned conventional drawbacks, the present invention provides a slit light source that can obtain a sufficiently long slit light with a simple and inexpensive configuration without reducing brightness in the peripheral area. a light emitting source that emits light of a certain wavelength; a collimating lens that converts the light from the light emitting source into parallel light;
A cylindrical lens-shaped diffraction grating is provided for converting the parallel light into an elliptical spot light, and the diffraction grating is configured to diffract the parallel light incident on the cylindrical lens or the elliptical spot light emitted from the lens. This is a slit light source characterized in that it is provided in a slit light source.

[Effect]

In other words, the slit light source utilizes the fact that when a diffraction grating emitted from a light emitting source is irradiated, the light diffracted by each grating interferes and is obtained as a plurality of spot lights on a straight line on the image plane. The light irradiated onto the diffraction grating is made into an elliptical spot light by a cylindrical lens, this is passed through the diffraction grating, and the tips of the plurality of obtained elliptical spot lights are superimposed (the focal length of the cylindrical lens (by setting the degree of overlap as appropriate), each long spot light may be made into an elliptical shape using a cylindrical lens, and then may be made into a single slit light beam.

〔Example〕

FIG. 1 is a diagram for explaining an embodiment of a slit light source according to the present invention.

- A collimating lens that converts the single wavelength diverging light from the diode 7 into parallel light, 9 a cylindrical lens that converts the parallel light into an elongated elliptical spot light 9a, 10 a plurality of optical fibers 10 to 10- A fiber array is arranged one-dimensionally in the X direction, and constitutes a diffraction grating. Each member is arranged so that its center coincides with the Z-axis direction. The arrangement direction of each optical fiber in the fiber array 10 is the axial direction of the cylindrical lens 9 (X in the figure).
direction).

The fiber array 10 is a fiber grating (
Product name: Machida Seisakusho).

Further, the fiber array 10 is arranged at any position other than the focal length f of the cylindrical lens 9 such that the elliptical spot light 9a is irradiated onto each of the fibers 10-1 to 10-.

In the configuration described above, the single wavelength light from the laser diode 7 is converted into parallel light by the collimating lens 8 and then enters the cylindrical lens 9.

The cylindrical lens 9 into which the parallel light is incident is parallel in the X-axis direction! 3 (same width) and elongated elliptical spot light 9a extending only in the y-axis direction, and makes it incident on the fiber array 10. As mentioned above, fiber array 1
0 is provided so that the arrangement direction of each fiber 10-1 to 10-claw is perpendicular to the axial direction (x direction) of the cylindrical lens 9, so the length direction (X direction) of the spot light 9a is
direction) is diffracted by each of the fibers 10-1 to 10-^, and becomes a plurality of spot lights 91 to 9a that are straight in the y-axis direction, and an elongated slit light 10a can be obtained.

Also, the degree of overlap of this slit light 10a in the y-axis direction (
By adjusting the area), the slit light 10a can have uniform brightness in the length direction. Although the embodiment has been described using the fiber array 10, a diffraction grating in which a plurality of slits (gratings) are formed in one plate may also be used.

In the embodiment described above, the fiber array 10 is arranged after the cylindrical lens 9, but even if the fiber array 10 is arranged in the opposite direction, similar slit light can be obtained. However, if the distance between them is increased, the top and bottom of the slit will be cut off depending on the size of the cylindrical lens 9, so it is necessary to arrange them sufficiently close to each other.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to generate slit light having a sufficient length without being out of focus in the depth direction with a very simple and inexpensive configuration.

[Brief explanation of the drawing]

FIG. 1 is a diagram for explaining an embodiment of a slit light source according to the present invention, and FIGS. 2 and 3 are diagrams for explaining a conventional slit light source. In the figure, 7 is a laser diode, 8 is a collimating lens, 9 is a cylindrical lens, and 9a. 91~9 nails are spot lights, 10 is a fiber array, 10
a is a slit light.

Claims (1)

[Claims] A light emitting source that emits light of a single wavelength, a collimating lens that converts the light from the light emitting source into parallel light, a cylindrical lens that converts the parallel light into elliptical spot light, and an arrangement direction of the plurality of gratings. the cylindrical lens is perpendicular to the axial direction of the cylindrical lens, and the diffraction grating diffracts parallel light incident on the cylindrical lens or elliptical spot light emitted from the lens. A slit light source characterized in that it is provided to do so.