JPH01262520A - Laser beam scanner - Google Patents

Abstract

PURPOSE:To increase a scanning speed of a laser beam by a simple constitution by radiating the laser beam so that a part overlapped on a scanning area of a reflected light is generated. CONSTITUTION:The title laser beam scanner is provided with a scanner mirror 13, an incident optical system for allowing plural laser beams L1, L2 and L3 to be made incident on a reflecting surface 15 of the scanner mirror 13 from different angles with respect to this scanner mirror 13, and a driving control means for bringing the scanner mirror 13 to driving control, and constituted so that the laser beam is radiated so that a part overlapped on a scanning area of a reflected light is generated, or so that the scanning area is different. That is, plural laser beams which are made incident on the scanner mirror from different directions are reflected at different angles, respectively and scan the scanning area. Accordingly, the number of times of the scan by the laser beam can be increased, and by overlapping reflected light beams of each laser beam which is made incident on the scanner mirror from different angles, on the same scanning area and radiating them, a scanning speed of the same scanning area is increased, and the resolution can be raised.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention J (Field of Industrial Application) The present invention relates to a laser beam scanner that scans a laser beam.

(Prior Art) A conventional laser beam scanner that scans a laser beam is configured as shown in FIG. 2 or 3.

The method shown in FIG. 2 is provided with a polygon mirror 2 that is rotationally driven by a motor or a turbine 1, and the laser beam L incident on the rotating polygon mirror 2 is reflected while changing the emission direction. In the method shown in FIG. 2, if it is necessary to increase the scanning speed, either increase the rotational speed of the driving motor or turbine 1 to shorten the scanning time per time, or The only option is to increase the number of scans per rotation.

In addition, in the method shown in FIG. 3, a mirror 4 is vibrated by a mirror drive device 3 consisting of an electromagnet, a pressure N element, etc., and the laser beam L incident on the vibrating mirror 4 is reflected while changing the emission direction. This is what I did. In this system, if it is necessary to increase the scanning speed, there is no choice but to increase the vibration frequency of the mirror 4 vibrated by the mirror drive device 3.

(Problems to be Solved by the Invention) However, there is a limit to increasing the rotational speed of the drive source of the polygon mirror 2 or increasing the vibration frequency of the mirror 4 in order to increase the scanning speed. The rotation speed of polygon mirror 2 is approximately 100,000 to 200,000 rpm, [! + The limit of the frequency of the mirror 4 is 10k)lz from the viewpoint of mechanical strength.

Furthermore, even if the number of surfaces of the polygon mirror 2 is increased, the scanning angle that can be scanned rapidly decreases because the laser beam has a certain thickness, and there is a limit to increasing the number of surfaces. Furthermore, increasing the diameter of the polygon mirror 2 in order to avoid this will significantly reduce the high-speed rotation resistance, so there is a limit from this point of view.

As described above, each of the conventional methods has a limit in increasing the scanning speed of one laser beam, and various problems have arisen in application to laser printers, high-speed inspection equipment, etc.

The present invention has been made in view of the above problems, and its purpose is to provide a laser beam scanner that has a relatively simple configuration and can increase the scanning speed of its laser beam. be.

[Structure of the Invention] (Measures f!j and operations for solving the problems) In order to solve the above problems, the present invention provides a laser beam scanner using a scanner mirror. an incident optical system that makes a plurality of laser beams enter a reflective surface of a scanner mirror from different angles, and a drive control means that drives and controls the scanner mirror, so that a portion overlaps with the scanning area of the reflected light, or The configuration is such that the laser beam is irradiated to different scanning areas.

According to this type of laser scanner, a plurality of laser beams incident on the scanner mirror from different directions are reflected at different angles to scan a scanning area. Therefore, the number of scans performed by the laser beam can be increased.

In this configuration, if the same scanning area is irradiated with the reflected light of each laser beam that is incident on the scanner mirror from different angles, the scanning speed of the same scanning area may be increased, for example, (If can be increased.

In addition, in the above configuration, where the laser beams incident on the scanner mirror from different angles are separately irradiated to different scanning area parts, the different scanning area parts can be scanned simultaneously, so that the entire scanning area can be scanned. The scanning speed can be increased and the optical system etc. can be made smaller.

(Embodiment) FIG. 1 shows a first embodiment of the present invention. In the figure, 10 is a laser generator, and a half mirror 11 and a total reflection mirror 12 are installed on the output optical path of this laser generator 10, and the half mirror 11 is a part of the laser beam L emitted from the laser generator 10. At the same time, a portion of the remaining laser beam L is transmitted. The total reflection mirror 12 is configured to completely reflect the transmitted laser beam L. And this half mirror 11 and total reflection mirror 12
constitutes an input optical system 14 that causes each of the reflected laser beams L to be incident on a polygon mirror 13 serving as a single scanner mirror from different directions.

The polygon mirror 13 has six reflecting surfaces 15 and is formed into a regular polygon. Further, this polygon mirror 13 is configured to be rotated at high speed in the direction of the arrow by a driving means such as a motor or a turbine (not shown).

An input optical system 14 consisting of a half mirror 11 and a total reflection mirror 12 is configured to make the plurality of laser beams L enter one point P on one reflective surface 15 of a single polygon mirror 13.

Thus, each laser beam Ll is reflected by the half mirror 11 and the total reflection mirror 12, respectively.

L2 forms an angle θ with one point P of the reflective surface 15 as the intersection,
Does it reflect on the reflective surface 15 of the polygon mirror 13? ! number of laser beams L1. L2 also forms the same angle θ. Here, when the polygon mirror 13 is rotated, scanning is performed at an angular velocity twice that of the polygon mirror 13 while maintaining the angle θ.

Moreover, as shown in FIG. 1, each laser beam L+, L
The scanning ranges S, S of 2 overlap by -IN1, and each laser beam L+, 12 scans its scanning object in this overlapping range sg. Furthermore, since the same scanning target surface portion is scanned by two laser beams L1.12, the scanning speed is substantially doubled. Since the scanning speed at which the scanning target is scanned is increased, the resolution of the apparatus using this can be improved.

Note that if the deflection angles of the laser beams L+ and L2 are set to be 2θ, the scanning angles of the laser beams Ls and L2 on the surface to be scanned will be equal. In addition, for example, an rθ lens or the like is provided in front of the irradiation of each laser beam Ll and L2 reflected by the reflective surface 15 of the polygon mirror 13, thereby creating laser beam spots at equal intervals and at a constant speed to scan the irradiation area. You may also do so.

Further, the present invention is not limited to the above embodiments. In the above embodiment, the reflective surface 15 of the polygon mirror 13
Each laser beam L+ reflects at.

Although the scanning image is scanned in the overlapping scanning range 811 of L2, the range scanned by each of the laser beams 11.degree. 12 may be different. In this way, the scanning if can be divided and each scanning range portion can be simultaneously scanned, so that the scanning speed of the entire scanning target range can be increased.

Moreover, in this case, each laser beam L1. Since the deflection angle (scanning angle) due to L2 can be reduced, the device can be made smaller.

Alternatively, the laser beam emitted from one laser generator may not be divided, but the laser beams emitted from a plurality of laser generators may be made incident on the polygon mirror 13.

Further, instead of the polygon mirror 13, a vibrating mirror such as a galvanometer mirror may be used.

Furthermore, if the number of laser beams that are incident on the scanner mirror from different directions is further increased, the number of scans can be increased and the scanning speed can be increased.

[Effect of the invention 1 As explained above, according to the laser scanner of the present invention,
Is it incident on the scanner mirror from different angles? ! Each of the several laser beams is reflected and scans the scanning area. Therefore, the number of times the laser beam is scanned and the scanning speed can be increased.

Further, in a system in which the same scanning area is irradiated with laser beams that are incident on the scanner mirror from different angles, the scanning speed of the same scanning area can be increased, and resolution can be increased, for example.

Furthermore, in a system that separately irradiates different scanning areas with laser beams that enter the scanner mirror at different angles, each of the different scanning areas can be scanned simultaneously, increasing the scanning speed of the entire scanning area. Furthermore, it is possible to downsize the optical system and the like.

[Brief explanation of the drawing]

FIG. 1 is a schematic structural explanatory diagram showing a first embodiment of the present invention, and FIGS. 2 and 3 are perspective views of different conventional devices. 10... Laser generator, 11... Half mirror 11
2... Total reflection mirror, 13... Polygon mirror, 1
4...Incidence optical system, 15...Reflection surface, L, Ll. L2...Laser beam. Applicant's representative Patent attorney Takehiko Suzue Figure 1 Figure 2 Figure 3

Claims (2)

[Claims] (1) In a laser beam scanner using a scanner mirror, the scanner mirror, an incidence optical system that makes a plurality of laser beams enter the reflective surface of the scanner mirror from different angles, and drive control of the scanner mirror. 1. A laser beam scanner, comprising: a drive control means, and irradiates a laser beam so that a portion overlaps with a scanning area of reflected light. (2) In a laser beam scanner using a scanner mirror, the scanner mirror, an input optical system that makes a plurality of laser beams enter the reflective surface of the scanner mirror from different angles, and drive control of the scanner mirror. 1. A laser beam scanner, comprising a drive control means, and irradiating a laser beam so that reflected light scans different areas.