JPH0260162B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of the Invention) The present invention relates to a semiconductor laser beam synthesis method for synthesizing laser beams emitted from a plurality of semiconductor lasers so that they overlap at a common spot;
In particular, the present invention relates to a semiconductor laser beam combining method that allows a combined beam with a cross-sectional shape close to a circle to be obtained.

(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. A semiconductor laser has conventionally been used as one of the means for generating a light beam in such a light beam scanning device. 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, this semiconductor laser
Currently, the output is at most when generating continuous oscillation.
Light beam scanning devices that require small, high-energy scanning light of 20 to 30 mW, such as recording materials with low sensitivity (metal films, amorphous films, etc.)
It is extremely difficult to use it in scanning recording devices that record on DRAW materials, etc.).

Also, some types of fluorophores are exposed to radiation (X-rays, alpha rays,
When irradiated with beta rays, gamma rays, ultraviolet rays, etc., some of this radiation energy is accumulated in the phosphor, and when this phosphor is irradiated with excitation light such as visible light, it It is known that phosphors exhibit stimulated luminescence, and by using such stimulable phosphors, radiation image information of a subject such as a human body can be stored in a storage layer containing a layer of stimulable phosphors. This stimulable phosphor sheet is scanned with excitation light such as a laser beam to generate stimulated luminescent light, and the resulting stimulated luminescent light is read out photoelectrically to produce an image signal. The applicant has already proposed a radiation image information recording and reproducing system that 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 Patent Application Laid-Open No. No. 55-12429, No. 55-116340, No. 55-
(No. 163472, No. 56-11395, No. 56-104645, etc.) In this system, the use of a light beam scanning device using a semiconductor laser is considered to scan the stimulable phosphor sheet on which radiation image information is stored and read the image information.
In order to stimulate a stimulable phosphor to emit light, it is necessary to irradiate the phosphor with excitation light of sufficiently high energy. It is extremely difficult to use it for reading image information in an information recording and reproducing system.

Therefore, when using a semiconductor laser in an optical beam scanning device, in order to obtain a sufficiently high-energy scanning beam from a semiconductor laser with a low optical output as described above, multiple semiconductor lasers are used, and the laser emitted from these semiconductor lasers is It is conceivable to combine the beams so that they overlap at the scanning point.

On the other hand, in the above-mentioned light beam scanning device, it is desirable that the cross-sectional shape of the scanning beam be a perfect circle in order to substantially match the resolution in the main scanning direction and the sub-scanning direction. However, as is well known, a laser beam emitted from a semiconductor laser has different divergence angles in a direction parallel to and perpendicular to the pn junction surface of the semiconductor laser, and its cross-sectional shape is circular. Conventionally, when using a semiconductor laser, when a light beam with a circular cross-sectional shape is required as described above, the laser beam emitted from the semiconductor laser is processed using an optical system such as a prism. The cross section was shaped into a perfect circle.

However, when multiple semiconductor lasers are used to obtain a high-energy scanning beam as described above, it is necessary to use optical systems such as the prisms for the number of semiconductor lasers, which increases the size of the scanning device. This also increases the cost of the scanning device.

(Objective of the Invention) Therefore, an object of the present invention is to provide a method for synthesizing a plurality of semiconductor laser beams, which can obtain a light beam having a substantially circular cross section without using an optical system such as the above-mentioned prism. The purpose is to

(Structure of the Invention) As described above, the semiconductor laser beam combining method of the present invention allows each laser beam to be individually It is characterized in that the inertial circular axes of the beam cross sections are combined so that they intersect with each other at substantially equal angular intervals on the common spot.

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

FIG. 1 shows an apparatus for implementing the first embodiment method of the present invention. As an example, four semiconductor lasers 11, 12, 13, 14 are arranged with their beam emission axes parallel to each other, and collimator lenses 21, 22, 23, 24, and reflecting mirrors 31, 32, 33, and 34 are provided. The light beams emitted from each semiconductor laser 11, 12, 13, 14 are directed to the collimator lens 2.
Parallel beam 41 by 1, 22, 23, 24,
42, 43, 44, and these parallel beams 41,
42, 43, 44 are the reflecting mirrors 31, 32,
It is reflected by 33 and 34 and enters a common galvanometer mirror 5.

The galvanometer mirror 5 rotates back and forth in the direction of arrow A in the figure, and the parallel beams 41, 42, 43, 4
Deflect 4. Deflected parallel beam 41,4
2, 43, 44 are focused into one spot S by a common focusing lens 6, and each is focused at this spot S. Therefore, if the surface to be scanned 7 is placed at a position where the spot S is irradiated, the surface to be scanned 7 will be exposed to high energy light beams emitted by the respective semiconductor lasers 11, 12, 13, and 14. The scanning beam is scanned in the direction of arrow B. Note that the surface to be scanned 7 is usually a flat surface, and therefore an fθ lens is used as the focusing lens 6.

FIG. 2 shows in detail how the four parallel beams 41, 42, 43, and 44 are combined at the spot S. As shown in FIG. 2, the parallel beams 41, 42, 43, and 44 emitted from the semiconductor lasers 11, 12, 13, and 14 each have a circular cross section; 42, 43, and 44 are combined so that their respective inertia circle axes P1, P2, P3, and P4 intersect at equal angular intervals (that is, in this case, at 45° intervals). Therefore, the cross-sectional shape of the combined light beam is approximately a perfect circle, although there are some irregularities at the periphery.

In the above embodiment, the parallel beams 41, 42, 4 emitted from the galvanometer mirror 5
3 and 44 are arranged in a direction perpendicular to the beam deflection direction, but these parallel beams 41, 42, 43, and 44 are of course parallel to each other and arranged in a direction other than the above. Good too.

FIG. 3 shows an apparatus for implementing the second embodiment method of the present invention. In this device, three semiconductor lasers 11, 12, 13 and a reflection mirror 31,
32 and 33 are arranged so that their respective beam axes are concentrated at one spot S.
Furthermore, for each of the semiconductor lasers 11, 12, 13, focusing lenses 61, 62, 63 are provided which turn the emitted light beams into convergent beams 51, 52, 53 which are focused on the spot S mentioned above. The focused beams 51, 52, 53 are deflected by the galvanometer mirror 5, and the spot S scans in a circular arc R. Therefore, in this case as well, the scanned surface 7 arranged along the arc P
The light beams emitted by the semiconductor lasers 11, 12, and 13 are combined and scanned by a high-energy scanning beam.

In this case as well, as shown in FIG. ), the cross-sectional shape of the combined light beam can be made approximately circular.

The embodiment in which a light beam obtained by combining a plurality of semiconductor laser beams is scanned has been described above, but the present invention also provides a method for making the cross-sectional shape of the combined beam approximately circular even when the combined beam is not specifically scanned. applicable. Further, the number of semiconductor laser beams to be combined is not limited to four or three, and the larger the number of beams to be combined, the closer the cross-sectional shape of the combined beam becomes to a perfect circle.

(Effects of the Invention) As explained in detail above, according to the semiconductor laser beam combining method of the present invention, semiconductor laser beams with low optical output can be combined to obtain a high-energy optical beam, and optical Since the light beam can be made to have a substantially circular cross section without using a system, the device that uses the composite beam can be miniaturized.
Furthermore, it can be formed at low cost.

[Brief explanation of drawings]

FIG. 1 is a schematic perspective view showing an apparatus for carrying out the semiconductor laser beam combining method according to the first embodiment of the present invention, FIG. 2 is an explanatory diagram showing the cross-sectional shape of the light beam combined by the above method, and FIG. 4 is a schematic perspective view showing an apparatus for carrying out the semiconductor laser beam combining method according to the second embodiment of the present invention, and FIG. 4 is an explanatory diagram showing the cross-sectional shape of the light beam combined by the method of the second embodiment. 6...Focusing lens, 11, 12, 13, 14...
...Semiconductor laser, 21,22,23,24...Collimator lens, 41,42,43,44...Parallel beam, 51,52,53...Convergent beam,
61, 62, 63...Focusing lens, P1, P2,
P3, P4...beam inertia circle axis.

Claims (1)

[Claims] 1. In a semiconductor laser beam combining method in which laser beams each having a circular cross section emitted from a plurality of semiconductor lasers are superimposed at a common spot, the laser beams are combined so that the circular axis of each beam cross section is on the common spot. A semiconductor laser beam combining method characterized in that the semiconductor laser beams are combined so that they intersect with each other at approximately equal angular intervals.