JPH06110009A - Laser light source unit - Google Patents

Abstract

PURPOSE:To provide the laser light source unit which has simple constitution and can easily adjust the astigmatism of a semiconductor laser by an optional quantity with respect to a laser light source unit which can adjusts the astigmatism of a semiconductor laser. CONSTITUTION:The laser light source unit is constituted by providing the semiconductor laser 11 which emits a laser beam, a converging lens 12 which is arranged nearby the laser beam emission end of the semiconductor laser 11 so as to converge the laser beam, and a couple of wedgelike sectioned transparent plates 14 and 14 which have their slanting surfaces put together to form one parallel plane plate and are arranged in the optical path of the laser beam relatively movably along the slanting surfaces and slantingly to the optical axis.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser light source device capable of adjusting the astigmatic difference of a semiconductor laser.

Laser light source devices are widely used as light sources for bar code readers and laser printers.

[0003]

2. Description of the Related Art In recent years, laser light source devices used for various purposes include He--Ne laser devices and semiconductor lasers (L
D) has been replaced, and miniaturization and cost reduction are advancing.

However, as shown in FIG. 8, in the semiconductor laser 11, the light emitting point differs between the vertical light wave and the horizontal light wave, and in general, the vertical light emitting point P emits the horizontal light. There is an astigmatic difference that is located 5 μm to 10 μm ahead of the point Q.

Therefore, conventionally, a plurality of cylindrical lenses or prisms for arranging the beam emitted from the semiconductor laser 11 by a collimator lens and changing the beam waist positions in the vertical direction and the horizontal direction to correct the astigmatic difference are arranged. Was.

Further, instead of the cylindrical lens or the prism, a transparent plane parallel plate is arranged between the semiconductor laser and the collimator lens so as to be inclined with respect to the optical axis to adjust the astigmatic difference. Etc.
0-241013).

[0007]

However, if a plurality of cylindrical lenses and prisms are provided at the exit end of the semiconductor laser in addition to the collimator lens, the number of parts becomes large and the apparatus becomes complicated, and astigmatism adjustment work is performed. Is not easy,
Parts cost and assembly adjustment cost are required.

Further, in the case where the plane parallel plates are arranged so as to be inclined with respect to the optical axis, the astigmatic difference can be changed by a fixed amount, but it is difficult to arbitrarily adjust the astigmatic difference. Therefore, an object of the present invention is to provide a laser light source device that can easily adjust an astigmatic difference of a semiconductor laser by an arbitrary amount with a simple configuration.

[0009]

In order to achieve the above object, a laser light source device of the present invention includes a semiconductor laser 11 for emitting a laser beam, as shown in FIG. 1 for explaining an embodiment. A converging lens 12 arranged in the vicinity of the laser beam emitting end of the semiconductor laser 11 for converging the laser beam and the slopes are superposed to form one parallel plane plate, and the parallel planes are relatively arranged along the slope. A pair of transparent plates 14 having a substantially wedge-shaped cross section, which are arranged so as to be movable in the optical path of the laser beam while being inclined with respect to the optical axis.

A transparent plate moving means 15 may be provided for moving the pair of transparent plates 14, 14 relative to each other to change the thickness of the stacked transparent plates.

[0011]

Since the plane parallel plates formed by the pair of transparent plates 14 and 14 are arranged so as to be inclined with respect to the optical axis of the laser beam, the astigmatic difference between the vertical direction and the horizontal direction is corrected by this, Further, by moving the pair of transparent plates 14 and 14 relatively along the slope, the correction amount of the astigmatic difference can be changed.

[0012]

Embodiments will be described with reference to the drawings. Figure 2
An example in which the present invention is applied to a barcode scanner is shown.

In the figure, reference numeral 10 denotes a semiconductor laser module containing a semiconductor laser 11 for emitting a laser beam and a converging lens 12 for converging the laser beam emitted from the semiconductor laser 11.

A spherical or aspherical convex lens is used as the converging lens 12, and is arranged in the vicinity of the laser beam emitting end of the semiconductor laser 11 so as to face the laser beam emitting end.
A pinhole aperture 13 is formed in the laser beam emitting portion of the semiconductor laser module 10, and the outer diameter of the laser beam is regulated here.

The laser beam emitted from the semiconductor laser module 10 is reflected by the plane mirror 19 and enters the scanning optical system 20. Then, the light is reflected by a small plane mirror portion 22 formed in the center of the concave mirror 21 and goes toward the reflecting surface of the polygon mirror 23.

The polygon mirror 23 is rotationally driven at a constant speed. Therefore, the laser beam is reflected by the reflecting surface of the polygon mirror 23 while continuously changing its direction. Then, one of the three plane mirrors forming the three-sided mirror 24 is reflected toward the bottom surface mirror 25.

On the surface of the scanning optical system 20, a hologram window 26 of a gradient index type in which a hologram material having a refractive index different depending on a place is formed on a transparent plate, or a relief type in which a diffraction grating by unevenness is formed on the transparent plate. A hologram window is arranged, and the laser beam reflected by the bottom surface mirror 25 passes through the hologram window 26 to be refracted and converged.

Since the polygon mirror 23 is rotating, the laser beam is scanned in one direction at high speed with the vertical oscillation direction of the light wave as the scanning direction, and the barcode 1
It hits 00 and is reflected.

FIG. 3 is a side view of the scanning optical system 20,
The laser beam that hits the barcode 100 outside the hologram window 26 passes through the hologram window 26 and is sequentially reflected by the bottom mirror 25, the three-sided mirror 24, and the polygon mirror 23, and then the concave mirror 2.
After being reflected by 1 and converged, and reflected by a small plane mirror 27, it is incident on a photodetector 28 arranged at the converging point of the laser beam by the concave mirror 21 and converted into an electric signal.

In this way, in the scanning optical system 20, the laser beam is scanned by the rotation of the polygon mirror 23, and the bar code 100 can be read by the output signal from the photodetector 28.

FIG. 1 shows the internal structure of the semiconductor laser module 10. Between the semiconductor laser 11 and the converging lens 12, a pair of transparent plates 14, 1 having a wedge-shaped cross section is formed.
4 are arranged in the form of one parallel plane plate by stacking the slopes.

The pair of transparent plates 14 and 14 are arranged to be inclined with respect to the optical axis of the laser beam within a horizontal plane. Therefore, as shown in FIG. 4, the emission point P in the vertical direction of the semiconductor laser 11 apparently moves to p and the emission point Q in the horizontal direction to q, respectively, and the amount of movement of the emission point Q in the horizontal direction is Is large, the apparent light emitting point p in the vertical direction and the apparent light emitting point q in the horizontal direction come close to each other, and astigmatism can be corrected.

Further, as shown in FIG. 1, one transparent plate 14 is fixed to the semiconductor laser module 10, while the other transparent plate 14 is driven forward and backward in the direction of arrow A by a voice coil motor 15. It is attached to a holder 16 which can be. Reference numeral 15a is a permanent magnet, and 15b is an electromagnetic coil.

As a result, the pair of transparent plates 14, 14 are moved relative to each other along the slope in the direction of inclination thereof, and the thickness t of the plane-parallel plate formed by the pair of transparent plates 14, 14 is freely set. Can be changed to.

When the thickness t of the plane-parallel plate is changed in this way, as shown in FIG. 5, the light emitting point P in the vertical direction and the light emitting point Q in the horizontal direction are further moved. Since the vertical direction and the horizontal direction are different, the correction amount of the astigmatic difference changes. Note that L _P , L _Q, and Δ in FIG.
, L _P is the distance between the light emitting point P in the vertical direction and the converging lens 12, L _Q is the distance between the light emitting point Q in the horizontal direction and the converging lens 12, and Δ is the astigmatic difference. Is.

Therefore, by moving the pair of transparent plates 14, 14 relative to each other along the slope by the voice coil motor 15 to change the thickness t of the plane-parallel plate, the light emitting point P in the vertical direction and the horizontal direction. The astigmatic difference of the light emitting point Q can be easily corrected by an arbitrary amount according to the variation of each product.

Specifically, when the astigmatic difference is large,
As shown in FIG. 6, a pair of transparent plates 1 that are overlapped with each other.
When the astigmatic difference is small, the thickness t of the plane-parallel plates formed by 4 and 14 may be increased, and the thickness t of the plane-parallel plates may be decreased as shown in FIG. .

[0028]

According to the laser light source device of the present invention, it is possible to easily adjust the astigmatic difference of the semiconductor lasers by an arbitrary amount and easily correct the astigmatic difference which varies among the semiconductor lasers. Have an effect.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment.

FIG. 2 is a perspective view of a laser beam scanning device according to an embodiment.

FIG. 3 is a side view of the scanning optical system according to the embodiment.

FIG. 4 is an operation explanatory diagram of the embodiment.

FIG. 5 is a diagram showing characteristics of an example.

FIG. 6 is an operation explanatory diagram of the embodiment.

FIG. 7 is an operation explanatory diagram of the embodiment.

FIG. 8 is a characteristic explanatory view of a semiconductor laser.

[Explanation of symbols]

 11 semiconductor laser 12 converging lens 14, 14 transparent plate

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Yuichiro Takashima, 1015 Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Fujitsu Limited

Claims (2)

[Claims] 1. A semiconductor laser (1) for emitting a laser beam.
1), a converging lens (12) arranged in the vicinity of the laser beam emitting end of the semiconductor laser (11) for converging the laser beam, and the slopes are superposed to form one parallel plane plate. Then, a pair of transparent plates (14, 14) having a substantially wedge-shaped cross-section are provided in the optical path of the laser beam so as to be relatively movable along the slope, and are arranged to be inclined with respect to the optical axis. A laser light source device characterized by the above. 2. A transparent plate moving means (15) for moving the pair of transparent plates (14, 14) relative to each other to change the thickness of the laminated plates.
The laser light source device described.