JPH0210310A - Multibeam light source - Google Patents

Abstract

PURPOSE:To reduce the size and weight of the multibeam light source by providing a collimator lens part and a plane microlens array part which further converts collimated light into multibeam light. CONSTITUTION:Divergent light emitted by an LD chip 1 is collimated by collimator lenses 3 (3A and 3B) into the collimated light, which is emitted out through microlens arrays 4 (4A-4C). Then the light which is emitted out through the microlens arrays 4 is diffracted to form may light spots at a distance. When projection light from a sensor head 20 is projected on a body 33 to be detected which passes in front of the head, the surface of the body 33 to be detected is irradiated with many light spots. Reflected light from the body 33 to be detected is photodetected by a position sensitive device for two-dimensional measurement provided in the sensor head 30 and specific arithmetic operation is carried out to recognize the shape of the body 33 to be detected.

Description

[Detailed Description of the Invention] Summary of the Invention A semiconductor laser is used as a light source, and a collimator lens portion that collimates the diverging light from the semiconductor laser and a flat micro lens array portion that further converts the collimated light into multiple beams are used. Prepared! Place the combined lens inside the cap. This makes the multi-beam light source smaller and lighter.

Aim for thermal stabilization.

TECHNICAL FIELD This invention relates to a multi-beam light source capable of projecting multiple spot lights.

Prior Art and its Problems In order to obtain a large number of light spots, at least a light emitting element and a lens array that creates a large number of light spots from the light emitted from the light source are required. Conventional multi-beam light sources use gas lasers as light-emitting elements, but the large size of the gas laser itself increases the size of the multi-beam light source, and there are also problems in that power consumption is large. When using a semiconductor laser as the light emitting element of a multi-beam light source, the light emitted from the semiconductor laser is diverging light, so a collimator lens is required.
Beam light sources become larger.

Summary of the Invention Object of the Invention The present invention aims to reduce the size and weight of a multi-beam light source.

Structure and effect of the invention A multi-beam light source according to the invention includes a semiconductor laser,
and a compound lens equipped with a collimator lens portion that converts the diverging light from the semiconductor laser into collimated light, and a flat micro lens array portion that further converts the collimated light into multiple beams; It is characterized by

Preferably, in the combination lens, the collimator middle lens part and the flat micro lens array part are integrated,
・A single plate-shaped compound lens.

The multi-beam light source according to the present invention uses semiconductor lasers as two light-emitting elements, and is constructed by housing a compound lens, which converts the diverging light from the semiconductor laser into collimated light and further converts it into multiple beams, into a cap together with the semiconductor laser. .

Therefore, the multi-beam light source can be made smaller and lighter. Furthermore, since a compound lens is used, the number of optical parts can be reduced, and optical axis adjustment becomes easy. Furthermore, since a semiconductor laser is used as a light emitting element, power consumption can be reduced. This reduces the amount of heat generated and can be expected to provide thermally stable operation.

DESCRIPTION OF THE EMBODIMENTS FIG. 1 is a partially cutaway perspective view showing an embodiment of a multi-beam light source according to the present invention.

Referring to this figure, a heat sink is fixed at approximately the center of the stem 8. This heat synchronizer may be formed integrally with the stem 8. Heat Synchro"
A semiconductor laser diode chip (LD chip) 1 is fixed to the second part. This LD chip 1 is provided so as to be located on the central axis Z of the stem 8 (this becomes the optical axis of the emitted light).

A compound lens 2 including a collimator lens 3 and a micro lens array 4 is arranged in front of the LD chip 1. The compound lens 2 is fixed at its ends to two support blocks 5, which are fixed to the stem 8 on either side of the heat synchronizer. Considering the X and Y axes in two directions orthogonal to the Z axis above.

The width of the support block 5 is long in the Y direction, and the center of this width is
It's on the axis. Further, the two support blocks 5 are located at equal distances from the Z-axis center in the X-axis direction.

Then, the 1u combination lens 2 is fixed to the block 5 at a position where the Z axis passes through the center of the collimator lens 3 and the center of the micro lens array 4.

Photo-de-chiktuff stem 6 is behind LD chip 1.
is fixed. The photodetector 7 receives the light emitted from the LD chip 1 and feeds it back to the drive circuit of the LD chip 1 to keep the emitted light layer of the LD chip 1 constant.

Heat synchronizer with LD chip 1 fixed.

Composite lens 2. A cap 9 is provided to cover the entire block 5 to which the compound lens 2 is fixed, and is fixed to the stem 8 by can sealing, adhesion, or other methods. A hole IO is formed in the top of the cap 9, and a transparent plate (plastic, glass, etc.; not shown) is provided in the hole IO to form a window. Open the entire front of cap 9.

The entire front surface may be covered with a transparent plate. The laser beam that has passed through the compound lens 2 is emitted to the outside through this hole IO.

LD chip 1. It goes without saying that the photodetector 7 is connected to a terminal 11 provided insulated on the stem 8 by wire bonding or the like.

Since the LD chip 1 and the compound lens 2 are housed within the cap 9, the influence of the external environment is extremely reduced. It is especially protected from dust adhesion.

Further, the LD chip 1 is located on the central axis Z of the stem 8, and the compound lens 2 and the support block 5 have a symmetrical shape with respect to the X-axis and the Y-axis and are arranged in such a manner.

Therefore, even if t(combined lens 2, support block 5, etc.) expands and contracts due to temperature changes, the ・IL(XY
In the plane, they thermally expand and contract in the same direction. Therefore, the LD chip 1 is always on two axes, and the optical axis is never deflected from the Z axis. Since the power lens 2 is firmly fixed by the two support blocks 5, it is resistant to vibrations and shocks.

Before explaining the compound lens 2, the collimator lens 3 and micro lens array 4 that make up the compound lens 2 will be individually explained.

The collimator φ lens 3 converts the diverging light emitted from the laser diode 1 into collimated light, and can use, for example, a Fresnel lens, an aspherical lens, or the like.

Some examples of micro lens arrays 4 are shown in FIG.
As shown in FIGS. 3 and 4. FIG. 2 shows a flat plate micro lens array 4A constructed by regularly arranging aspherical micro lenses 4a on one flat plate. Figure 3 shows a flat plate micro lens array 4B in which distributed index micro lenses 4b created by ion exchange method etc. are regularly arranged, and Figure 4 shows a flat plate with micro Fresnel lenses 4C. Each of the micro lens arrays 4C is shown as being regularly arranged.

FIGS. 5(A), (B), (C), and (D) show the above collimator lens 3. Examples of compound lenses constructed by combining micro lens arrays 4A to 4C are shown.

The compound lens 2A shown in FIG. 5(A) is composed of a combination of a flat micro φ Fresnel φ lens 3A as a collimator φ lens and a micro lens array 4B created by an ion exchange method. The flat micro φ Fresnel lens 3A is located at a position where it collimates the diverging light from the LD chip 1, and the micro lens array 4B
are respectively arranged at positions where the laser beam collimated by the flat plate micro Fresnel lens 3A is incident, and are fixed to each other by suitable coupling means.

A power lens 2B shown in FIG. 5(B) has a micro Fresnel collimator lens 3 and a micro lens array 4B formed on one substrate. For example, the micro lens array 4B is fabricated on one surface of a glass substrate -F by an ion exchange method, and the micro Fresnel collimator lens 3 is formed on the other surface of the same substrate by a molding method. A compound lens 2B integrated on the substrate can be made.

The compound lens 2C shown in FIG. 5(C) includes a micro Fresnel collimator lens 3 and a plurality of aspherical micro lenses.
Aspherical micro lens array 4 with lenses formed
It is composed of A.

On a single plastic or glass substrate, L
A compound lens 2C is constructed by molding a micro Fresnel 6 collimator ◆lens 3 on the surface from which the laser beam from the D-chip 1 is emitted, and an aspherical micro lens array 4A on the other surface.

The power lens 2D shown in FIG. 5(D) is a flat lens 3B.
and an aspherical micro lens array 4A. The flat lens 3B is a distributed index flat lens manufactured by an ion exchange method. A composite lens 2D is constructed by pasting this flat lens 3B and an aspherical micro lens array 4A with adhesive.

In FIG. 1, diverging light emitted from an LD chip 1 is collimated by a collimator lens 3 (3A, 3B), and then collimated by a micro lens array 4 (4
A, 4B, 4C) and exits to the outside. micro·
The light emitted through the lens array 4 is diffracted, and many light spots are generated in the distance due to concave refraction (for example, the patent application ``Multi Beam Projector'' filed on June 20, 1986 by the same applicant and the same agent) ).

FIG. 6 shows an application example in which a multi-beam light source is used in a multi-beam projector.

The multi-beam light source is housed within the sensor head 3o. The sensor head 3o is connected to a drive power source and a processing device 31. The sensor head 30 is for recognizing an object 33 to be detected which is transported by a transport device in front of the sensor head 30 .

When the light emitted from the sensor head 20 is projected onto an object to be detected 33 passing in front of it, the surface of the object to be detected 33 is illuminated by a large number of light spots.

The reflected light from the object to be detected 33 is reflected by a position sensitive sensor for two-dimensional measurement provided in the sensor head 30.
Device (Position 5 sensitiveD)
The detected object 3 is detected by a predetermined calculation from each light receiving position.
3 shapes can be recognized. The detected object 33 that has moved from the direction shown by arrow A is moved from arrow B to arrow C by the direction switching device (path shown) depending on the result of shape recognition.
The signal is sent in the direction shown in .

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway perspective view showing an embodiment of a multi-beam light source according to the present invention. Figure 2 is a perspective view of an aspherical micro-lens array, Figure 3 is a perspective view of a distributed index micro-lens array, and Figure 4 is a perspective view of a micro-lens array.
FIG. 2 is a perspective view of a Fresnel lens array. Figure 5 (A
), (B), (C). (D) each shows an example of a compound lens. FIG. 6 is a perspective view showing an example of application of the multi-beam light source. 1...LD chip. 2.2A, 2B, 2C, 2D... compound lenses. 3.3A, 3B...Collimator lens. 4.4A, 4B, 4C...Micro lens φ array. 9... Cap. Patent applicant Tateishi Electric Co., Ltd. Agent Patent attorney Kenji Ushiku (1 other person) Figure 2 Figure 1

Claims (1)

[Claims] A compound lens comprising a semiconductor laser, a collimator lens section that converts the diverging light from the semiconductor laser into collimated light, and a flat micro lens array section that further converts the collimated light into multiple beams is contained in one cap. A multi-beam light source characterized by being built into.