JPS60238811A - Optical beam scanner - Google Patents

Abstract

PURPOSE:To execute a scan in a constant state in the scanning direction by switching selectively an optical path of an optical beam by an optical path switching device, reflecting it by each mirror surface of the surface and the rear side of a reflection mirror, executing a scan, and utilizing both going and returning rotations of a galvanometer mirror. CONSTITUTION:As for an optical beam 2 emitted from an optical beam generating means 1, its optical path is switched selectively by an optical path switching device 3. Optical beams 2a, 2b are reflected by reflection mirrors 4, 5, respectively, and made incident on a galvanometer mirror 6. As for a reciprocating rotating mirror 7 of the galvanometer mirror 6, both the surface 7a and the rear side 7b are mirror surfaces, and the optical beams are made incident on 7a, 7b, respectively. Switching of the optical path and driving of the galvanometer mirror 6 are synchronized, and when the optical beam 2a is emitted, the mirror 7 executes a going rotation, and when the optical beam 2b is emitted, the mirror 7 executes a returning rotation. The optical beams 2a, 2b are reflected by reflection mirrors 9, 10, and focused onto a surface to be scanned 12 by a condensing lens 11.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to deflecting a light beam by a galvanometer mirror.
The present invention relates to a light beam scanning device for scanning, and more particularly to a light beam scanning device that utilizes both forward and backward rotation of a galvanometer mirror for optical deflection to enable high-speed scanning.

(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. In such a light beam scanning device, one of the above-mentioned optical deflectors includes:
Galvanometer mirrors have been widely used in the past. When using this galvanometer mirror as a light deflector, attempts have been made to utilize both the forward rotation of the mirror and the backward rotation for scanning the light beam in order to increase the scanning speed (scanning period).

However, in this type of conventional optical beam scanning device, the optical beam is deflected using the same mirror surface of the galvanometer mirror.
Since the mirror is scanned, the scanning direction of the light beam is naturally opposite to each other when the mirror rotates forward and backward. Therefore, in this case, the data order for each scanning line (i.e., in a scanning recording device, the recording data that modulates the light beam,
In scanning reading devices, it was necessary to alternately rearrange the order of read data.

Also, when certain types of phosphors are irradiated with radiation (X-rays, alpha rays, beta rays, gamma rays, ultraviolet rays, etc.), a portion of this radiation energy is accumulated in the phosphors, causing them to become visible. It is known that when irradiated with excitation light such as light, a phosphor exhibits stimulated luminescence depending on the accumulated energy.Using such a stimulable phosphor, radiographic images of the human body, etc. Information is once recorded on a stimulable phosphor sheet having a layer made of a stimulable phosphor, and this stimulable phosphor sheet is scanned with excitation light such as a laser beam to generate stimulated luminescence light. The present applicant has developed a radiation image information recording and reproducing system that photoelectrically reads out the stimulated emitted light to obtain an image signal, and outputs it as a visible image to a recording material such as a photographic light-sensitive material, a CRT, etc. based on this image signal. has already been proposed by. (Unexamined Japanese Patent Publication No. 55
-12429, 55-116340, 55-1
No. 63472, No. 56-11395, No. 56-104
645 etc.). When the above-mentioned light beam scanning device, which uses the same mirror surface of the galvanometer mirror and performs light beam scanning in both forward and backward rotations, is used for image reading in this system, the stimulated luminescence light is excited. Since this occurs with a certain degree of response delay in response to light irradiation, the trailing direction of the read signal due to the response delay of the stimulated luminescence light is alternately reversed for each scanning line, leading to deterioration in the quality of the read image.

(Objective of the Invention) The present invention has been made in view of the above circumstances, and it is possible to deflect and scan a light beam by using both forward and backward rotations of a galvanometer mirror. An object of the present invention is to provide a light beam scanning device that can always keep the scanning direction constant.

(Structure of the Invention) The light beam scanning device of the present invention uses a galvanometer mirror whose front and back surfaces are mirror surfaces as a galvanometer mirror that deflects and scans the light beam, and uses a galvanometer mirror that deflects and scans the light beam. The optical path is selectively switched in two directions by an optical path switcher, and the light beams traveling in each optical path are made incident on each mirror surface of the galvanometer mirror by a reflecting mirror, respectively.
As a result, each light beam deflected by each mirror surface is scanned by a scanning optical system consisting of a reflecting mirror and a focusing lens.
Scanning is performed in the same direction at the same scanning position.

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

The figure shows a light beam scanning device according to one embodiment of the present invention. For example, a light beam 2 emitted from a light beam generating means 1 such as a laser is emitted from an ultrasonic light deflector (for example,
The optical path is selectively switched by an optical path switching device 3 consisting of an acousto-optic optical deflector (AOD), and the light beams travel as light beams 2a and 2b, respectively. That is, when an optical path switch drive signal S1 synchronized with a drive signal for a galvanometer mirror 6, which will be described later, is input to the optical path switch 3, the primary light is emitted as a light beam 2a, and the optical path switch drive signal S1 is When the input is stopped, the zero-order light is emitted as a light beam 2b.

The light beams 2a, 2b are each reflected by a reflecting mirror 4.5 and incident on a galvanometer mirror 6. This galvanometer mirror 6 is a mirror 7 that rotates back and forth.
Both the front surface 7a and the back surface 7b of the mirror 7 are mirror surfaces, and the light beam 2a12b is incident on the front surface 7a1 and the back surface 7b of the mirror 7, respectively. Galvanometer mirror drive device 8 that drives the galvanometer mirror 6
A galvanometer mirror drive signal S2 synchronized with the optical path switching device drive signal S1 described above is input to the galvanometer mirror drive signal S2, and the mirror 7 of the galvanometer mirror 6 is rotated back and forth in the directions of arrows A and B in the figure. be moved. That is, the optical path switching device drive signal S1 is input to the optical path switching device 3, and the optical path switching device 3 outputs the optical beam 2.
As soon as a is emitted, the mirror 7 rotates forward (rotates in the six directions of arrows in the figure), and the input of the optical path switching device drive signal S1 to the optical path switching device 3 is stopped, and the input from the optical path switching device 3 to the optical path switching device 3 is stopped. When the light beam 2b is emitted, the mirror 7 rotates backward (as indicated by the arrow B in the figure).
direction). The light beam 2a reflected on the front surface 7a of the mirror 7 is deflected by the forward rotation of the mirror 7, and the light beam 2b reflected on the back surface 7b of the mirror 7 is deflected by the backward rotation of the mirror 7. .

A reflecting mirror 9.10 is disposed in each optical path of the deflected light beam 2a12b, and the deflected light beam 2a1
2b are reflected in the same direction by these reflecting mirrors 9.10. A focusing lens 11 (usually an fθ lens) is disposed at a position where both of the light beams 2a and 12b reflected by the reflecting mirror 9.10 are incident, and the light beams 2a and 2b that have passed through the focusing lens 11 are is focused onto the scanned surface 12 (normally, the scanned surface 12 is a flat surface, so an fθ lens is used as the focusing lens 11). Here, the reflecting mirrors 9.10 reflect light beams 2a, 2 reflected at each mirror 9.10.
The deflection plane b makes the same angle with respect to the focusing lens 11,
Further, the respective light beams 2a and 2b are arranged so that their deflection directions are parallel to each other, so that the light beams 2a and 2b are
are respectively focused on the scanned surface 12 and scanned on a common scanning line C. The light beam 2a is reflected by the front surface 7a of the mirror 7 and is deflected by the forward rotation of the mirror 7, and the light beam 2b is reflected by the back surface 7b of the mirror 7 and deflected by the backward rotation of the mirror 7. These light beams 2
a and 2b scan the common scanning line C in the same direction.

In this way, according to this device, the light beam 2 is deflected and scanned using both the forward and backward rotations of the galvanometer mirror 6, so the scanning period becomes sufficiently short and high-speed scanning becomes possible. .

Note that as the light beam generating means 1, a semiconductor laser, a gas laser, a light emitting diode, etc. are used.

In addition to the above-mentioned AOD, an electro-optical optical deflector (EOD) or a type that mechanically drives a reflecting mirror can be used as the optical path switch 3;
Since the optical path switching angle of the light beam can be set sufficiently large,
It is more preferable because the reflective mirror 4.5, galvanometer mirror 〇, or reflective mirror 9.10 can be easily installed, and the response speed is sufficiently fast. Furthermore, in the embodiment described above, the common focusing lens 11 is used for the two light beams 2a12b, but the respective light beams 2a,
A dedicated focusing lens may be provided for the focusing lens 2b, and a reflecting mirror 9.10 may be set so that the light beams 2a and 2b passing through each focusing lens scan on the same scanning line. The optical paths of the passed light beams 2a and 2b may be bent by a prism, a reflecting mirror, or the like so that the light beams 2a and 2b scan on the same scanning line. Furthermore, by making the shape of the light beam 2a12b on the mirror 7 an SI image parallel to its deflection surface, and by arranging a pair of cylindrical lenses before and after the beam optical path with the mirror 7 in between,
Scanning line C due to wobbling of galvanometer mirror 6
It is more preferable to eliminate the distortion.

(Effects of the Invention) As explained in detail above, according to the light beam scanning device of the present invention, high-speed scanning is possible using both the forward and backward rotations of the galvanometer mirror, and the scanning direction is always constant. This eliminates the need to provide a complicated circuit for converting the order of recorded data and read data for each scan as described above, and furthermore, when used as a scanning reader in the radiation image information recording and reproducing system described above, Since the trailing direction of the read signal due to the response delay of the exhaustion light becomes the same, it is possible to reduce the deterioration in image quality of the read image due to this trailing.

[Brief explanation of drawings]

The figure is a schematic perspective view showing one embodiment of the light beam scanning device of the present invention. 1... Light beam generating means 2.2a12b... Light beam 3... Optical path switching device 4
．． 5.9.10... Reflection mirror 6... Galvanometer mirror 7... Mirror 7a... Mirror surface 7b... Back side of mirror 11 River focusing lens C... Scanning line

Claims (1)

[Claims] A galvanometer mirror having a light beam generating means, an optical path switching device that selectively switches the optical path of the light beam emitted from the light beam generating means in two directions, and a mirror whose front and back surfaces are mirror surfaces; a reflecting mirror that causes the light beams traveling along optical paths in two directions to be incident on each mirror surface of the galvanometer mirror; a reflecting mirror that causes each of the light beams deflected by the galvanometer mirror to scan in the same direction at the same scanning position; and a focusing mirror. A light beam scanning device consisting of a scanning optical system made up of lenses.