JPS6243620A - Semiconductor laser light source device - Google Patents

Abstract

PURPOSE:To obtain a composite beam which has a sectional shape close to a circle and high light intensity by making elliptically sectioned laser beams from two projection systems consisting of plural semiconductor lasers incident on a polarization beam splitter in different directions, and multiplexing two laser beams. CONSTITUTION:Elliptically sectioned beams 23a-23c from three semiconductor lasers 20a-20c of a beam projection system 25 are projected in parallel so that their short axes are in a line; and they becomes parallel beam flux 26 through collimator lenses 21a-23c and reflecting mirrors 22a-22c and enter a polarization beam splitter (PBS)40 which transmits P polarized light and reflects S polarized light. Similarly, laser beams from three semiconductor lasers 30a-30c of the 2nd beam projection system are incident on the PBS40 through collimator lenses 31a-31c and reflecting mirrors 32a-32c. The two incident beams polarized as shown by arrows A1 and A2 are multiplexed and projected, and then converted into a spot S on a scanning surface 44 through an optical polarizer 42 and a condenser lens 43, so that the spot is scanned as shown by an arrow C.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of the Invention) The present invention relates to a semiconductor laser light source device used in a light beam scanning device, etc., and more particularly, to a semiconductor laser light source device for combining laser beams emitted from a plurality of semiconductor lasers into one laser beam. The present invention relates to a semiconductor laser light source device.

(Technical Background and Prior Art of the Invention) Conventionally, light beam scanning devices that scan a light beam by deflecting it with an optical deflector have been widely put into practical use, for example, in various scanning recording devices, scanning reading devices, and the like. One of the means for generating a light beam in such a light beam scanning device
As one example, semiconductor lasers have been conventionally used. This semiconductor laser has many advantages, such as being smaller, cheaper, and consumes less power than gas lasers, and can be directly modulated by changing the drive current.

However, on the other hand, when this semiconductor laser is continuously oscillated, the current output is only 20 to 30 mW.
Therefore, it is extremely difficult to use it in optical beam scanning devices that require energetic scanning light, such as scanning recording devices that record on recording materials with low sensitivity (such as DRAW materials such as metal films and amorphous films). be.

Also, some types of fluorophores are exposed to radiation (X-rays, α-rays, β-rays, γ-rays, etc.).
When the phosphor is irradiated with rays, electron beams, ultraviolet rays, etc., a portion of this radiation energy is accumulated in the phosphor, and when the phosphor is irradiated with excitation light such as visible light, the phosphor emits light according to the accumulated energy. It is known that light bodies exhibit stimulated luminescence, and by using such stimulable fluorescers, radiation image information of a subject such as a human body can be transferred to a stimulable phosphor (1m stimulable fluorescer). ), and this stimulable phosphor sheet is scanned with excitation light such as a laser beam to generate stimulated luminescence light. The applicant has already proposed a radiation image information recording and reproducing system that photoelectrically reads an image signal and outputs the radiation image of the subject as a visible image to a recording material such as a photographic light-sensitive material, CRT, etc. based on this image signal. (Japanese Unexamined Patent Publication No. 55-124
No. 29, No. 55-116340, No. 55-16347
No. 2, No. 56-11395, No. 56-104645, etc.). In this system, it has been considered to use a light beam scanning device using a semiconductor laser to scan the M-activated phosphor sheet on which radiation image information is stored and read the image information, but In order to cause the phosphor to stimulate luminescence, it is necessary to irradiate the phosphor with excitation light of sufficiently high energy. It is also extremely difficult to use it for reading image information in a system.

Therefore, as mentioned above, in order to obtain a sufficiently high-energy scanning beam from a semiconductor laser with low optical output, it is possible to use multiple semiconductor lasers and combine the laser beams emitted from these semiconductor lasers into one beam. . As shown in Japanese Patent Application No. 59-121089, a semiconductor laser light source device that synthesizes a plurality of laser beams in this way is constructed such that the optical axes of each laser beam are parallel to each other. It has been considered that the laser beams are arranged in parallel to each other, each made into a parallel beam by a collimator lens, and then arranged in a line parallel to each other to be combined into one beam.

However, as is well known, the laser beam emitted from a semiconductor laser has different divergence angles in the direction parallel to and perpendicular to the p-n junction of the semiconductor laser, and its cross-sectional shape is circular. As shown in FIG. 4, when a plurality of laser beams 10 are arrayed and synthesized, the cross-sectional shape of the synthesized beam 11 ends up having a chipped edge. The edge of such a composite beam 11 cannot be effectively used for optical scanning, and therefore, an optical scanning device using such a composite beam has low energy utilization efficiency.

In addition, in order to increase the intensity of the combined beam, it is possible to increase the number of laser beams to be combined, but when multiple laser beams are arranged and combined in a row, the cross-sectional shape of the combined beam becomes elongated, which can be used for actual optical scanning. The problem arises that it cannot be done.

(Object of the Invention) The present invention has been made in view of the above circumstances, and provides a semiconductor laser light source device that has a cross-sectional shape close to a perfect circle and can obtain a composite beam with extremely high C light intensity. The purpose is to provide the following.

(Structure of the Invention) The semiconductor laser light source device of the present invention comprises collimating laser beams emitted from a plurality of semiconductor lasers and having a circular cross section, and arranging the laser beams so that the short axes of the beam cross sections lie substantially in a straight line. A first beam emitting system that emits a beam bundle whose cross-sectional lengths are approximately equal in length and width, and a second beam emitting system that is formed in the same manner as li′i1 and emits a beam bundle that has approximately the same cross-sectional shape as the beam bundle. system and a t=t beam splitter, the beam beam emitted from the first beam exit system is transmitted through the polarizing film of the beam splitter, while the beam beam emitted from the second beam exit system is transmitted through the polarizing film of the beam splitter. The beams from each beam exiting system are combined by being arranged so as to be reflected by a polarizing film, and the beams from the first beam exiting system and the second beam exiting system are combined.
The beam bundle from the beam exit system is made to enter the polarizing beam splitter so that the respective beam arrangement directions are substantially perpendicular to each other on the polarizing film and the east centers of the respective beams substantially overlap. It is something to do.

(Embodiments) Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

FIG. 1 shows one embodiment of a semiconductor laser light source device of the present invention. - As an example, three semiconductor lasers 20a
, 20b, and 20c are arranged with their beam emission axes parallel to each other, and these semiconductor lasers 20a,
20b, 20c, collimator lenses 21a121b, 21c, anti-1if122a,
22b.

22c is provided to form a first beam exit system 25. The laser beams 23a, 23b, 23C emitted from the respective semiconductor lasers 20a, 20b, 20c are made into parallel beams by the collimator lenses 21a, 21b, 21c, and these parallel beams are turned into parallel beams by the reflecting mirror 22.
a, 22b, and 22c, the beams are narrowed so that they come close to each other, become a beam bundle 26, transmit the P@ light beam, and enter a polarizing beam splitter 40 having a polarizing film 40△ that reflects the S-polarized beam. .

Here, each semiconductor ray' of the first beam emitting system 25,
F20a-G are arranged so that the pn junction plane is parallel to the X-y plane in FIG.
3a to 3C are linearly polarized light in a plane parallel to the xy plane, as shown by arrow A1. The polarized light 11Q40A of the polarizing beam splitter 40 is polarized in the above direction (
P-polarized) laser beams 23a to 23C are disposed so as not to pass therethrough.

Laser beam 23 incident on polarizing beam splitter 40
As is well known, the optical loss angle of a"C increases in the direction parallel to and perpendicular to the pn junction surface of the semiconductor lasers 20a-c, and the cross-sectional shape thereof is elliptical, but in this implementation In an embodiment, the semiconductor lasers 20a to C emit beams 23a to C with a ratio of the short axis to the long axis of the cross section of 1:3.
is used.

The laser beams 23a to 23C incident on the polarizing beam splitter 40 are arranged so that their short axes are substantially aligned, so these laser beams 23a to 23C
The cross-sectional shape of the beam bundle 26 made up of the following is approximately equal in length and width.

On the other hand, apart from the first beam emitting system 25, three semiconductor lasers 30a, 30b, and 30c are arranged with their beam emitting axes parallel to each other, and a collimator is provided for each of these semiconductor lasers 30a, 30b, and 30C. ') 731a, 31b, 31c, reflection 1i32a.

32b and 32c are provided, and the second beam injection system 35
is formed. The semiconductor lasers 30a, 30b1
Laser beams 33a, 33b, emitted from 30c,
The beams 33C are made into parallel beams by the collimator lenses 31a, 31b, and 31c, and these parallel beams are reflected by the reflecting mirrors 32a, 32b, and 32c, narrowed in distance so that they come close to each other, and become a beam bundle 36, which is sent to the polarizing beam splitter 40. incident on . Here, the semiconductor lasers 30 a - c of the second beam emitting system 35 are similar to the semiconductor lasers 20 a - C of the first beam emitting system 25 , and a laser beam 33 a that enters the polarizing beam splitter 40 is used. -c are also arranged so that their short axes are substantially aligned, so these laser beams 33a
The cross-sectional shape of the beam bundle 36 consisting of ~C is the same as the cross-sectional shape of the beam bundle 26 from the first beam injection system 25.

However, in the beam bundle 26 incident on the polarizing beam splitter 40, each of the laser beams 238 to C'If
In contrast, in the beam bundle 36 incident on the polarizing beam splitter 40, the y-axis direction is
They are arranged in two axes perpendicular to the axis. In other words, the semiconductor lasers 30a to 30C are arranged so that their pn junction surfaces are parallel to the yz plane, and the polarizing beam splitter 4
The laser beams 33a to 33c incident on the laser beam 33 are linearly polarized in a plane parallel to the yz plane, as shown by arrow A2.

In this way, the polarizing film 40A of the polarizing beam splitter 40 has an angle of 90° with respect to the polarization plane of the laser beams 23a to 23c.
The polarizing beam splitter 4 reflects the polarized (S-polarized) laser beams 33a-c within the rotated plane.
0, a beam bundle 36 made up of these laser beams 338-C and a combined beam 41 formed by combining the beam bundle 26 made up of the laser beams 23a-C are emitted.

As shown in FIG. 2, the beam bundle 26 and the beam bundle 3
6, the beams are incident on the polarizing beam splitter 40 in such a way that the centers of the respective beams coincide with each other on the polarized light 414°A of the polarizing beam splitter 40. Therefore, the combined beam 41 is composed of the six laser beams 2
3a to 3c and 33a to C are synthesized with high density, and has a cross-sectional shape close to a perfect circle without chipping at the edges.

This composite beam 41 is deflected, for example, by an optical deflector 42 that rotates back and forth in the direction of arrow B in FIG. The beams are concentrated into one combined beam spot S, and each beam is focused at this spot S. Therefore, if the surface to be scanned 44 is placed at a position where the spot S is irradiated, the surface to be scanned 44 will be 6
The tree laser beams 23a to 33a to 33a are combined into an extremely high-energy scanning beam to produce an arrow C.
Normally, the scanned surface 44 is a flat surface, and therefore an fθ lens is used as the focusing lens 43.

In the bag opening of the semiconductor laser light source, as mentioned above, the combined beam 41 has a cross-sectional shape close to a perfect circle with no chipped edges, and the intensity distribution is approximately uniform, so that the six The energy of the laser beams 23a-C133a-C can be effectively used for optical scanning.

Note that in the embodiment described above, the first and second
Laser beams 23a-c and 33a, which are the same in number and have the same cross-sectional shape, are emitted from the beam exit system 25.35.
For example, as shown in FIG. Laser beams 51a, 5 with different numbers and different cross-sectional shapes
1b, 51c and 61a161b. Even in this case, as long as the cross-sectional shapes of the beam bundles 50 and 60 have substantially equal vertical and horizontal lengths and are substantially equal to each other, the effects described above can be obtained.

Further, the number of laser beams emitted from the first and second beam emitting systems is, of course, not limited to the number described above, and may be any number as long as it is two or more. When laser beams emitted from li number of semiconductor radars are arranged as they are to form a beam bundle, the number of arranged beams is naturally determined by the cross-sectional shape (ratio of short axis to long axis) of the laser beams. If the laser beam emitted from the semiconductor laser is shaped using a beam shaper to make it more flat, a beam bundle can be made up of a larger number of laser beams. It becomes possible to synthesize at high density.

(Effects of the Invention) As explained in detail above, the semiconductor laser light source device of the present invention can combine laser beams emitted from a large number of semiconductor lasers to an IQ density to obtain an extremely high energy beam, for example. As mentioned above, a scanning beam with high energy is required, and it can be used for recording on RAW materials or reading radiation image information from stimulable phosphor sheets, and it can be used for a number of semiconductor lasers that have already been used. Taking advantage of its characteristics, it is used in a wide range of fields.

Moreover, according to the device of the present invention, it is possible to obtain a composite beam with a cross-sectional shape close to a perfect circle and an approximately uniform intensity distribution.
The energy of the laser beam can be used extremely effectively for optical scanning and the like.

[Brief explanation of the drawing]

FIG. 1 shows an example of the semiconductor laser light source device of the present invention IIl!
Figure 2 is a perspective view showing the 1 mode, and Figure 2 is a perspective view showing how the laser beams are combined in the above embodiment system δ. Fig. 3 is a schematic diagram showing another example of laser beam synthesis by the device of the present invention, and Fig. 4 is a schematic diagram showing an example of how laser beams are synthesized by the conventional device. be. 20a, 20b, 20c, 30a, 30b, 3
0c... Semiconductor lasers 21a, 21b, 21c, 31a, 31b,
31c...] remeter lenses 23a, 23b, 23c, 33a, 33b, 33c. 5+a, 51b, 51c, 61a, 61
b...Laser beam 25...First beam injection system 26.36.50.60...Beam bundle 35...Second
Beam emission system 40...Polarizing beam splitter 40A...Polarizing film 41...Combined beam 101 Fig. 2 Fig. 3 0A Fig. 4 Unit

Claims (1)

[Claims] Laser beams emitted from a plurality of semiconductor lasers with circular cross-sections are collimated and arranged so that the short axes of the beam cross-sections are aligned substantially in a line, so that the vertical and horizontal lengths of the cross-sections are approximately equal. a first beam emitting system that emits a beam as a beam; a polarizing beam splitter having a polarizing film arranged to transmit the beam emitted from the first beam emitting system; A laser beam having a circular cross-section is collimated, and then arranged so that the short axes of the beam cross-section are aligned substantially in a line, and emitted as a beam bundle having approximately the same cross-sectional shape as the beam bundle, and this beam bundle becomes the polarized beam. a second beam emitting system arranged so as to be reflected by the polarizing film of the splitter and combined with the beam beam from the first beam emitting system, the beam emitting from the first beam emitting system; and the beam flux from the second beam exit system are incident on the polarizing beam splitter such that their respective beam arrangement directions are substantially perpendicular to each other on the polarizing film, and their respective beam flux centers substantially overlap. A semiconductor laser light source device characterized by: