JPS6291912A - Optical beam scanner - Google Patents

Abstract

PURPOSE:To make a synchronizing signal generating part small-sized to build it easily and solidly in a picture information read-write device by arranging a rotating polygonal mirror, a synchronizing signal generating light source part, and a light receiving part in the same housing. CONSTITUTION:A polygonal mirror 2 formed to a regular octahedron is provided which is fixed to a continuously rotating revolving shaft 1 and is enclosed with a mirror housing 4. A light source 10 for synchronizing signal and a condenser lens 12 are arranged on the inside under the center of a window 8 of the mirror housing 4, and an optical beam 22 for synchronizing signal is made incident on the face of the polygonal mirror 2 on which a picture information optical beam 6 is made incident. A grid 14 where transparent parts and opaque parts are formed alternately in the scanning direction and a light receiving part 16 are arranged on the inside above the center part of the window 8. The light receiving part 16 consists of a condensing bar 18 formed with a transparent material and a photodetector 20. The output of the photodetector 20 is inputted to a control circuit 22 which controls the read or write timing of picture information.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a light beam scanning device, and more particularly to a light beam scanning device for reading and recording image information.

[Technical background]

2. Description of the Related Art A light beam scanning device is known in which a light beam emitted from a light source such as a laser oscillator is reflected and deflected by a galvanometer mirror, a rotating polygon mirror, or the like for scanning. When applied to an image information recording device, this device modulates a light beam in accordance with an image information signal using, for example, an acousto-optic modulator (AOM), and scans a recording medium containing a photosensitive material with the modulated light to create an image. Information can be recorded. In addition, when applied to image information reading devices,
The image information carried by the recording medium can be read by scanning the recording medium on which image information is recorded with a light beam and detecting the transmitted light, reflected light, or emitted light. In particular, when reading a radiation image recorded on a stimulable phosphor that exhibits so-called photostimulability, it is necessary to irradiate the phosphor with a laser beam as excitation light and scan it, and then read the stimulated luminescence light. , the stored images can be played back.

In such a light beam scanning device, a scanning synchronization signal is required whether it is applied to recording or reading image information. A conventional device for generating a synchronization signal for a light beam scanning device is, for example, in a light beam recording device such as a laser printer, the light beam for the synchronization signal is deflected together with the light beam for image information by a rotating polygon mirror, and the light beam for the synchronization signal is deflected by a scanning lens. After passing through an Fθ lens, the light beam is separated into an image information light beam and a synchronization signal light beam by a splitting means, and the synchronization signal light beam is projected onto a synchronization signal generation grid. The grid is arranged at a position where the light beam is focused by the Fθ lens, and behind the grid there is a long cylindrical light guide member made of acrylic resin and a photodetector such as a photomultiplier tube at the end thereof. A photodetecting means is arranged. This photodetector generates a synchronization signal by receiving a portion of the grid-transmitted light of the synchronization signal light beam scanning the grid with a photomultiplier tube.

[Problems solved by the present invention]

By the way, in the above-described light beam scanning device, since the grid is arranged at the position where the light beam is focused by the scanning lens, the length of the grid must be equal to the width of the recording medium in the scanning direction. Therefore, the grid and the photoreceptor become large, and the length of the optical path to the grid and the photoreceptor must be made long, so that there is a problem that the device becomes large and the cost also increases.

The present invention has been made in view of the above-mentioned problems of conventional light beam scanning devices, and is compact, substantially integrated with a rotating polygon mirror, and easily and robustly used as a device for writing and reading image information. An object of the present invention is to provide a light beam scanning device that can be incorporated into a system.

[Structure of the invention]

A structural feature of the present invention that achieves the above object is that in a light beam scanning device that projects an image information light beam emitted from an image information light source onto a rotating polygon mirror for scanning, the polygon mirror is rotated. Possible to support polygonal mirror housing,
A light source device for projecting a synchronizing signal light beam onto a polygon mirror and a light receiving device for receiving the reflected beam of the synchronizing signal light beam by the polygon mirror are provided. This can be suitably applied to devices that read recorded radiation images.

〔Example〕

Examples of the present invention will be described below. As shown in FIGS. 1 and 2, the light beam scanning device of the embodiment includes a regular octahedral polygon mirror 2 fixed to a rotating shaft 1 that rotates continuously and surrounded by a mirror housing 4. As shown in FIGS. The mirror housing 4 is provided with a window 8 through which a light source 24 is provided.
An image information light beam 6 emitted from the polygon mirror 2 is incident on the polygon mirror 2, and a reflected and deflected image information light beam 6 is emitted.

A synchronizing signal light source 10 and a condensing lens 12 are arranged below and inside the center of the window 8, and the synchronizing signal light beam 22 is made to be incident on the same surface as the polygon mirror 2 on which the image information light beam 6 is incident. On the other hand, above and inside the center of the window 8, a grid 14 in which transparent parts and opaque parts are alternately formed in the scanning direction and a light receiving part 16 are arranged. The light receiving section 16 includes a light collecting bar 18 made of a transparent material and a photodetector 20. Photodetector 2
The output of 0 is input to a control circuit 22 that controls the timing of reading or recording image information.

In the above configuration, the synchronizing signal light beam 22 emitted from the synchronizing signal light source 10 enters the rotating polygon mirror 2 via the condensing lens 12. The light beam 22 deflected by the rotation of the polygon mirror 2 reaches the grid 14, and the light receiving section 16 forms a synchronization signal from the light transmitted through the grid 14 of the light beam and supplies it to the control circuit 22 for control. circuit 2
2, a recording or reading timing control signal is formed and output.

On the other hand, the image information light beam 6 generated from the light source 24 is
The image information light beam 7 that is incident on the polygon mirror 2, reflected and deflected by the polygon mirror 2, reaches a recording medium (not shown), scans it, and is converted into a timing control signal output from the control circuit 22. Recording or reading of image information is performed under retiming control.

In the above embodiment, the light receiving section 16 that receives the synchronizing signal light beam is composed of a grib and a photodetector 20,
Although the synchronizing signal is generated during all scanning of the image information light beam 6, the light receiving section may be simply constituted by a photodetector, and only the starting point signal of the image information light beam may be generated.

Further, as another embodiment, it is also possible to use different surfaces of the rotating polygon mirror as the reflection surface of the synchronization signal light beam and the reflection surface of the image information light beam.

〔Effect of the invention〕

The present invention is constructed by arranging the rotating polygon mirror, the light source section for generating a synchronizing signal, and the light receiving section in the same housing as described above. Therefore, the synchronization signal generating section is compact and can be easily and robustly incorporated into a device for writing and reading image information.

[Brief explanation of drawings]

FIG. 1 is a perspective view of the main parts of a light beam scanning device according to an embodiment of the present invention, and FIG. 2 is a sectional view taken along the line 1--H shown in FIG. 1...Rotation axis, 2...Polygon mirror, 4...Mirror housing, 6...Image information light beam, 8...Window , 10...Light source for synchronization signal, 14...Grid, 16...
Light receiving section, 18... Focusing bar, 20...
...Photodetector, 22...Control circuit.

Claims (2)

[Claims] (1) In a light beam scanning device that projects an image information light beam emitted from an image information light source onto a rotating polygon mirror for scanning, a polygon housing that rotatably supports the polygon mirror is synchronized with the polygon mirror. A light beam scanning device comprising: a light source device for projecting a signal light beam; and a light receiving device for receiving a beam reflected from the synchronization signal light beam by the polygon mirror. (2) The light beam scanning device according to claim 1, wherein the image information light beam and the synchronization signal light beam are arranged so as to be incident on the same surface of the polygon mirror.