JPH04216514A - Laser beam generator - Google Patents

Abstract

PURPOSE:To prevent the spot system on a photosensitive body from having the value higher than a desired value by adjusting the mounting angle of a semiconductor laser element with the optical axis of a collimating lens. CONSTITUTION:An element holder 16, screws 101, 102 and a spring 103 are provided as a means for adjusting the mounting angle of the semiconductor laser element 12 with the optical axis of the collimating lens 11. The element holder 16 is fastened by two pieces of the screws 101 and one piece of the screw 102. Three pieces of these screws correspond to the positions corresponding to the vertexes of a triangular shape. The screw 101 exists in the bottom and the screw 102 exists in the peak part. In addition, one end 16b side is put into a flow state by the elasticity of the spring 103. The element holder 16 is, therefore, rotated and adjusted together with the element 12 around the one end 16b as a fulcrum according to a screwing-down quantity if the screwing state of the screw 102 is changed. Then, the central axis of the exit light is aligned to the mounting reference plane of the laser element 12 by changing the screwing-down quantity of the screw 102 even if the above-mentioned central axis inclines with the axis perpendicular to the above-mentioned reference plane.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser light generating device that can be used as a scanning light source for laser printers, laser copying machines, laser facsimiles, and the like.

0002

2. Description of the Related Art There is a laser light generating device that includes a semiconductor laser element and a collimator lens that converts the light beam emitted from the semiconductor laser element into a parallel light beam. In FIG. 4, reference numeral 1 indicates a semiconductor laser element. This semiconductor laser element has a mounting reference surface 1A. In the laser beam generator, the arrangement of each member is determined so that when the reference surface 1A is attached in close contact with the mounting surface of the laser beam generator, the positional relationship of the emitted light beam with respect to the optical system is appropriate. There is.

[0003] This means that when the central axis of the light beam emitted from this semiconductor laser element is O1-O1, this central axis O
This is based on the assumption that 1-O1 is perpendicular to the reference plane 1A, that is, θ=90°. Conventionally, there are techniques disclosed in JP-A No. 63-287976, JP-A-63-84056, JP-A-64-6917, etc. as laser light generators. Among the adjustment elements between the laser element and the collimating lens, which is one of the optical systems, there is a disclosure regarding each position adjustment mechanism in the vertical, horizontal, and optical axis directions.

0004

[Problem to be solved by the invention] However, in reality,
There are variations in the angle of the central axis O1-O1 of the emitted light with respect to the reference surface 1A, and when the ideal axis perpendicular to the reference surface 1A is O-O, the product is manufactured with an inclination to this axis O-O. There are things that can happen. When such a semiconductor laser element is used in a conventional laser beam generator, the axis O-O
A deviation occurs in the central axis O1-O1 of the emitted light. In other words, the emitted light is tilted with respect to the collimating lens and other lenses whose optical axis is set to align with the axis OO.

When such a laser beam generator is used for optical scanning, the light intensity distribution of the spot on the photoreceptor, which is the medium to be scanned, does not have a normal symmetrical Gaussian distribution. In other words, as shown in FIG. 5, the spot diameter D becomes larger than the desired value, and the light intensity distribution also becomes biased.

The present invention provides a laser beam generation method that can prevent the spot diameter on a photoreceptor from becoming larger than a desired value due to the inclination of the central axis of the emitted light beam with respect to the reference plane of the semiconductor laser element. The device is intended to provide optical scanning.

[0007]

[Means for Solving the Problems] In order to achieve the above object, the laser beam generating device according to the present invention includes an angle adjusting means for adjusting the mounting angle of the semiconductor laser element with respect to the optical axis of the collimating lens. did.

[0008]

[Operation] Even if the luminous flux of the semiconductor laser element with respect to the reference plane is tilted, it is adjusted to the same state as if there was substantially no tilt.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a laser beam generator according to the present invention will be described with reference to FIGS. 1 to 3. 1 to 3, the semiconductor laser device 12 is fitted into a hole formed in the center of a device holder 16 having a substantially disk shape. Further, the flange of the semiconductor laser element 12 is fixed to the element holder 16 by being pressed by a pressing plate 18 screwed to the element holder 16.

One end 16a of the element holder 16 located at the lower side in FIG. 1 is screwed to the base member 15 with two screws 101. Also, the other end 16 of the element holder 16 located above in FIG.
b and the base member 15 are fastened together with one screw 102. This one end 16b is stepped, and an extensible spring 103 is inserted into the step by a screw 102. Furthermore, element holder 1
6 is formed into a shallow step shape with one end 16a remaining.

In other words, the element holder 16 has two screws 1
It is fastened by a total of three screws: 01 and one screw 102, and these three screws correspond to the positions corresponding to the vertices of the triangle, with screw 101 located at the bottom and screw 102 at the top. . Moreover, one end 16b side has a spring 103
It has a float-like shape due to its elasticity.

Therefore, if the screwing state of the screw 102 is changed, the element holder 16 can be adjusted depending on the screwing amount.
is rotated and adjusted together with the semiconductor laser element 12 using one end 16b as a fulcrum. In addition, at that time, the tightening state of the screw 101 is also adjusted as necessary. In this way,
Even if the central axis O1-O1 of the emitted light of the semiconductor laser element 1 is tilted with respect to the axis O-O as shown in FIG.
By changing the amount of screwing in of the screw 102, it is possible to match the axis O-O.

For this reason, the element holder 16,
The screws 101, 102, spring 103, etc. are referred to as angle adjusting means.

A cylindrical portion 15a is formed at the center of the base member 15 and protrudes forward, corresponding to the right side in FIG. A cylindrical inner periphery 15b having a smooth surface is formed on the inner periphery of the cylindrical portion 15a, and a female thread 15c with a larger diameter than the inner periphery 15b is formed on the front side of the inner periphery 15b. is formed.

A lens cell 13 having a collimating lens 11 adhesively held on the inner peripheral side thereof is fitted into the inner peripheral portion 15b. As shown in an enlarged view in FIG. 3, this lens cell 13 has a guide groove 13a in the axial direction of its central axis. The outer circumferential surface of the lens cell 13 is processed to be smooth and is fitted to the inner circumferential portion 15b without wobbling. Furthermore, this guide 13a has a cylindrical portion 1.
The tip of the guide pin 22 screwed in from the outer circumferential side of 5a is fitted. Thereby, the lens cell 13 is fitted into the inner peripheral portion 15b so that it can move in the direction of the optical axis of the collimating lens 11, but cannot rotate around the optical axis.

A ring-shaped leaf spring 20 is interposed between the lens cell 13 and the flange portion 15d of the cylindrical portion 15a, and the leaf spring 20 pushes the lens cell 13 forward from the base member 15. is energized by

A ring-shaped cell retainer 21 is screwed into the female thread 15c to restrict movement of the lens cell 13 due to the biasing force. A slot 21a is formed at the front end of the cell presser 21.

A flange member 14 is screwed to the entire surface of the base member 15, and serves as a reference for attachment to equipment.A cylindrical portion 14a formed on the flange member 14 surrounds the outer periphery of the cylindrical portion 15a. There is.

A holder 17 is provided on the back side of the base member 15.
is fixed, and the electrical equipment board 1 is held by this holder 17.
9 is fixed. Furthermore, the joint surface between the holder 17 and the base member is finished to be smooth so that both can slide smoothly.

Then, using an appropriate jig, while relatively moving the element holder 16 and the base member 15 in all directions in a plane perpendicular to the lens optical axis, the semiconductor laser element 12 and the collimating lens 11 are optimally aligned. The relative position can be determined and the optical axis can be adjusted.

Collimation adjustment is performed by fitting the tip of a screwdriver or the like into the slot 21a of the cell holder 21 and rotating the cell holder 21 around the optical axis. Cell holder 2
When the lens cell 1 is rotated, the cell retainer 21 moves back and forth in the optical axis direction along the female thread 15c of the base member 15, and along with this movement, the lens cell 13 moves back and forth in the optical axis direction.

The movement of the lens cell 13 is controlled by the base member 1.
This is done by using the smooth inner circumferential surface 15b of No. 5 as a guide and using the guide pin 22 to prevent rotation. The movement accuracy of this lens cell 13 is as follows:
Although it depends on the accuracy of the fit with the inner circumferential portion 15b, it is much easier to achieve high accuracy when fitting smooth surfaces together, as in this example, than when fitting screws together. can.

Therefore, as is well known, if the collimation is adjusted so that the distance from the surface of the active layer, which is the light emitting point of the semiconductor laser element 12, to the principal point of the collimating lens 11 matches the focal length of the lens 11, the semiconductor laser element 1
The laser beam from 2 can be made into a parallel beam.

Furthermore, since the lens cell 13 is prevented from rotating, even after the collimation adjustment, the lens cell 1
3 does not rotate and can prevent optical axis deviation due to collimation adjustment. Therefore, collimation adjustment and optical axis adjustment can be performed independently without interfering with each other, making adjustment extremely easy. . Furthermore, since collimation adjustment can be performed by rotating the cell holder 21 from the front side, there is no need to provide an adjustment mechanism on the side surface of the lens cell 13 and the cylindrical portion 15a of the base member 15 into which it is fitted. , it is possible to obtain a miniaturized laser light generating device with a short dimension in the optical axis direction.

[0025] In addition to the above example, a spline structure in general can be applied as a means for fitting the lens cell to the base member so that it can move in the optical axis direction but cannot rotate around the optical axis. . For example, the fitting part between the lens cell and the base member may be square, D-shaped, or oval-shaped, and in this case, the base member side is a square hole with a precise fit or a square hole with guide surfaces on at least two sides. It is possible to make modifications such as pressing the lens cell against the guide surface using an elastic body inserted in the gap.

[0026] This has the advantage that there is no need to specially provide a rotation stopper. In addition, while the outer shape of the lens cell is cylindrical, a V-shaped receiver is formed on the base member,
The outer periphery of the lens cell may be pressed against this receiver to provide a suitable rotation stopper.

As the biasing means for the lens cell, an appropriate elastic material having a similar function may be used instead of the leaf spring. Alternatively, the lens cell may be provided with a flange, and an elastic material may be interposed between the flange and the base member to urge the lens cell.

As described above, in this example, even if there are variations in the direction of the central axis of the emitted light from the semiconductor laser element, by using the angle adjustment means, it is possible to correctly align the optical axis of the optical system such as the collimating lens. be able to.

[0029]

[Effects of the Invention] According to the present invention, even if there is variation in the amount of inclination of the central axis of the emitted light beam of the semiconductor laser element, it is possible to prevent the spot diameter on the photoreceptor from becoming larger than the desired value due to this variation. It can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a laser beam generator according to the present invention.

FIG. 2 is a cross-sectional view of a laser light generating device according to the present invention.

FIG. 3 is a perspective view of a lens cell, which is a component of the laser beam generator according to the present invention.

FIG. 4 is an explanatory diagram of the state of a luminous flux emitted from a semiconductor laser element.

FIG. 5 is an explanatory diagram of a light intensity distribution of a spot on a photoreceptor by a laser light generating device according to the prior art.

[Explanation of symbols]

Claims (1)

[Claims] 1. A laser light generating device having a semiconductor laser element and a collimating lens that converts a light beam emitted from the semiconductor laser element into a parallel light beam, in which an attachment angle of the semiconductor laser element with respect to an optical axis of the collimator lens is adjusted. A laser beam generating device characterized by comprising an angle adjusting means for adjusting the angle.