JPH0685399A - Laser light source - Google Patents

Abstract

PURPOSE:To obtain a small and cheap laser light source requiring no collimator lend. CONSTITUTION:First and second cylindrical lenses 4, 5 are arranged such that the refracting directions of cylindrical faces thereof cross perpendicularly each other and focal lines thereof cross each other. Light emitting point of semiconductor laser 1 is set at the cross point. This simple structure can convert an elliptical emitted light into a circular parallel luminous flux.

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 used in an optical pickup device or the like.

[0002]

2. Description of the Related Art FIG. 5 shows a conventional laser light source device. In FIG. 5, 1 is a semiconductor laser, 2 is a light emitted from the semiconductor laser 1, 3 is a collimator lens for converting the emitted light 2 into parallel light, 4 is a first cylindrical lens, and 5 is a second.
It is a cylindrical lens of.

Next, the operation will be described. The emitted light 2 from the semiconductor laser 1 is converted into parallel light by the collimator lens 3. The emitted light 2 from the semiconductor laser 1 is not circular, but has an elliptical shape with an aspect ratio of about 1: 3. Therefore, the emitted light 2 after passing through the collimator lens 3
The shape of is also elliptical. Therefore, the first cylindrical lens 4 and the second cylindrical lens 5 are used to convert the cross-sectional shape of the emitted light 2 into a circular shape.

Generally, the minor axis direction of the elliptical cross section of the emitted light 2 is called the horizontal direction, and the direction perpendicular to this is called the vertical direction. That is, the radiated light 2 is diverged only in the horizontal direction by the first cylindrical lens 4 to increase the horizontal beam diameter, and then the radiated light 2 diverged in the horizontal direction is collimated by the second cylindrical lens 5. In addition, the horizontal beam diameter of the radiated light 2 is enlarged to obtain the radiated light 2 having a circular cross-sectional shape.

[0005]

The conventional laser light source device has a problem that the collimator lens 3 is required and it is difficult to construct the device in a small size and at a low cost.

The present invention has been made to solve the above problems and does not require a collimator lens.
The objective is to obtain a small and inexpensive laser light source device, and to obtain a laser light source device that can reduce the number of assembly steps associated with the simplification of the configuration. Furthermore, the astigmatism of emitted light is corrected. It is an object of the present invention to provide a laser light source device that can be manufactured.

[0007]

In the laser light source device according to the present invention, the refraction directions of the two cylindrical surfaces are orthogonal to each other, and the focal lines of the two cylindrical surfaces intersect each other. An optical element and a semiconductor laser light source having a light emitting point at the intersection of the focal lines on the optical surface of the optical element are provided.

Further, the two optical surfaces are composed of one optical element.

Further, a position adjusting mechanism is provided in the optical axis direction of the semiconductor laser light source.

In addition, a position adjusting mechanism is provided in the optical axis direction of the two optical surfaces of the optical element.

[0011]

In the laser light source device configured as described above, the optical elements are arranged so that the refraction directions of the two cylindrical surfaces are orthogonal to each other and the focal lines of the two cylindrical surfaces intersect each other, By arranging the emission point of the semiconductor laser at the intersection, both horizontal and vertical radiated light become parallel light beams, but the perspective angles of the laser light sources on the respective cylindrical surfaces are different, and the elliptical radiated light is changed. It is converted into a circular parallel light flux.

Further, the two optical surfaces whose optical axes are orthogonal to each other are constituted by one optical element, thereby simplifying the constitution.

Further, the position adjusting mechanism corrects the astigmatism of the emitted light by generating astigmatism in the opposite direction with the same amount as the astigmatism of the optical system of the emitted light.

In addition, by displacing the position adjusting mechanism provided on the first or second optical surface together with the optical surface, an astigmatism opposite to the astigmatism of the radiated light is generated and the radiated light is emitted. Corrects astigmatism of light.

[0015]

EXAMPLES Example 1. An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, the semiconductor laser 1, the emitted light 2, the first cylindrical lens 4, and the second cylindrical lens 5 are the same as those in the conventional example of FIG. 5, the collimator lens is omitted, and 6 is the first cylindrical lens. The focal line of the lens 4 and the focal line 7 of the second cylindrical lens 5 are shown. The focal line 6 of the first cylindrical lens 4
The emission point of the semiconductor laser 1 is located on the intersection of the focal line 7 of the second cylindrical lens 5 and.

Next, the operation will be described. First cylindrical lens 4 and second cylindrical lens 5
Both have a positive refracting power, and their focal lines, that is, the straight lines on which the parallel light beams are focused when they enter the cylindrical lenses 4 and 5 are orthogonal to each other, and the optical axis of the semiconductor laser 1 is On the same plane perpendicular to.

In the optical system, the semiconductor laser 1, the first cylindrical lens 4, and the second cylindrical lens 5 are arranged in this order, and the first cylindrical lens 4 is arranged to refract the emitted light in the vertical direction. There is a lens action, and the second cylindrical lens 5 has a lens action in a direction in which light rays are refracted in a direction orthogonal to the refraction direction of the first cylindrical lens 4.

The emitted light 2 from the laser light source 1 is incident on the first cylindrical lens 4. The first cylindrical lens 4 has a function of refracting light rays in the vertical direction, and since the focal line of the first cylindrical lens 4 is on the semiconductor laser light source 1, the emitted light 2 is converted into a parallel light flux only in the vertical direction. To be done.

The emitted light after passing through the first cylindrical lens 4 is diffused only in the horizontal direction, and the emitted light spreads only in the horizontal direction. Therefore, when the incident light enters the second cylindrical lens 5, the emitted light is an ellipse. The cross section of the radiated light 2 which has been present is converted into a substantially circular shape. Second cylindrical lens 5
Then, the radiated light 2 that is also converted into parallel light in the horizontal direction and that has passed through the second cylindrical lens 5 is converted into a circular parallel light flux.

Through the above process, the emitted light 2 from the laser light source 1 is divided into the first and second cylindrical lenses 4 and 5 by two.
The collimator lens 3 is made up of a simple optical system consisting of surfaces.
Is converted into a circular parallel light beam without using.

Example 2. A second embodiment of the present invention will be described with reference to the drawings. In FIG. 2, reference numeral 8 denotes one optical element 8 having two cylindrical surfaces whose optical axes are orthogonal to each other. In the first embodiment, the first and second cylindrical surfaces are composed of independent cylindrical lenses 4 and 5, respectively. However, as shown in FIG. 2, one optical surface composed of two cylindrical surfaces whose optical axes are orthogonal to each other is used. It may be composed of the element 8.

Example 3. Next, a third embodiment will be described with reference to the drawings. In FIG. 3, 9 is a position adjusting mechanism of the semiconductor laser 1. In the first embodiment, the emitted light 2 from the semiconductor laser 1 is assumed to be an astigmatic light beam, but the emitted light 2 from the semiconductor laser 1 generally has astigmatism. The astigmatism of the synchrotron radiation 2 differs depending on the element of the semiconductor laser 1,
It is desirable to adjust the laser light source device here.

The amount of refraction of light rays by the lens is proportional to the distance between the light source and the lens surface. That is, if the lens is located farther from the light source, the refractive power of the lens increases as the lens is placed. This also applies to the cylindrical lens.

When the position of the light source of the semiconductor laser 1 shifts from the plane including the focal line 6 of the first cylindrical lens 4 and the focal line 7 of the second cylindrical lens 5 toward the cylindrical lens, the first cylindrical lens is moved. Lens 4
Although the amount of refraction of the light beam by and the amount of refraction by the second cylindrical lens 5 are also reduced, the change in the amount of refraction of the second cylindrical lens 5 is small and astigmatism occurs.

When the semiconductor laser 1 is displaced in the reverse direction, astigmatism occurs in the reverse direction due to the same principle. That is, by adjusting the position of the semiconductor laser 1, the first cylindrical lens 4 and the second cylindrical lens 5 produce an astigmatism in the opposite direction with the same amount as the astigmatism of the emitted light 2 by the optical system. It is possible to generate and correct the astigmatism of the emitted light.

Example 4. Although the position adjusting mechanism 9 is attached to the semiconductor laser 1 in the above embodiment, the position adjusting mechanism 10 may be attached to the first and / or the second cylindrical lenses 4 and 5 as shown in FIG.

[0027]

Since the present invention is constructed as described above, it has the following effects.

That is, the first and second cylindrical lenses are arranged so that the refraction directions of the two cylindrical surfaces are orthogonal to each other and the focal lines of the two cylindrical surfaces intersect each other, and at the intersections thereof. By arranging the emission points of the semiconductor laser, both horizontal and vertical radiated light become parallel light beams, but the perspective angles of the laser light sources on the respective cylindrical surfaces are different, and even if a collimating lens is not used, an ellipse is obtained. Radiant light can be converted into a circular parallel light flux, and the device can be made small and inexpensive.

Further, since the two optical surfaces are composed of one optical element, the structure can be simplified and the assembling process can be simplified, and the cost can be reduced.

Further, a position adjusting mechanism is provided in the optical axis direction of the semiconductor laser, and by displacing this position adjusting mechanism, astigmatism opposite to that of the emitted light is generated, whereby the emitted light is emitted. Astigmatism can be corrected.

In addition, by providing the position adjusting mechanism on at least one of the two optical surfaces, the astigmatism of the emitted light can be corrected by displacing the position adjusting mechanism together with the optical surface.

[Brief description of drawings]

FIG. 1 is a structural explanatory view of a laser light source device according to an embodiment of the present invention.

FIG. 2 is a structural explanatory view of a laser light source device according to Embodiment 2 of the present invention.

FIG. 3 is a structural explanatory view of a laser light source device according to Embodiment 3 of the present invention.

FIG. 4 is a structural explanatory view of a laser light source device according to Embodiment 4 of the present invention.

FIG. 5 is a structural explanatory view showing a conventional laser light source device.

[Explanation of symbols]

 1 Semiconductor Laser 2 Radiation Light 4 First Cylindrical Lens 5 Second Cylindrical Lens 8 Optical Element Comprising Two Cylindrical Surfaces with Axis Across Each Other 9 Position Adjusting Mechanism 10 Position Adjusting Mechanism

Claims (4)

[Claims] 1. A semiconductor laser light source and an optical surface having at least two unidirectional lens functions, the refraction directions of light rays are orthogonal to each other, and the laser light source is located on an intersection of focal lines of the optical surface. A laser light source device comprising an optical element in which a light emitting point is located. 2. The laser light source device according to claim 1, wherein the two optical surfaces are composed of one optical element. 3. The laser light source device according to claim 1, further comprising a position adjusting mechanism in the optical axis direction of the semiconductor laser light source. 4. The laser light source device according to claim 1, wherein the position adjusting mechanism is provided in the optical axis direction of the two optical surfaces.