JP2583919B2 - Optical scanning device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical scanning device that performs recording or reading by scanning light in one direction using a beam modulated according to image information.

2. Description of the Related Art Conventionally, a configuration shown in FIG. 6 is known as an example of an optical scanning device that scans light in one direction and performs recording or reading. Hereinafter, the conventional optical scanning device will be described with reference to FIG.

As shown in FIG. 6, a laser beam from a laser light source 101 is modulated by a modulator 102 in accordance with an image signal, the modulated beam is expanded by a beam expander 103, and the expanded beam is subsequently reflected by a reflecting mirror 104. The beam is expanded by the beam expander 103, and the expanded beam is given a deflection angle θ by a deflector 105 such as a rotating polyhedral mirror. An F · θ lens (constant speed scanning lens) having a focal length f with the laser beam given the deflection angle θ
Recording using a reflection mirror 107 by 106, or condensed on a surface 108 to be scanned such as a reading medium, and recording while scanning,
Or it was reading.

As another conventional optical scanning device, a configuration described in Japanese Utility Model Laid-Open No. 57-93907 and SPIEV01.498P135-139 is known. Hereinafter, the conventional optical scanning device will be described with reference to FIG. As shown in FIG. 7, the laser beam 20 from the laser light source 201
2 is imaged by the condenser lens 203 at the modulation center of the optical modulator 204. After the modulation, the laser beam 202 is converted into a parallel light again by the collimating lens 205, and the x-axis acousto-optic deflector 207 and the y-axis acousto-optic deflector 208 pass through the stop 206 to obtain x · y.
Deflected axially. After passing through the deflectors 207 and 208, the optical path and the beam shape of the laser beam 202 are shaped by the relay lens 209, and the beam spot is imaged on the surface 211 to be scanned by the objective lens 210, thereby deflecting a minute range at high speed and high accuracy. . Then, the laser beam 202 is slightly deflected in the x direction, and the Y-axis movement table 212 and the X-axis movement table 213 are operated by the operation of the Y-axis movement motor 214 and the x-axis movement motor 215, thereby increasing the area of a wide range. The laser beam 202 is completely deflected. At this time, the laser length measuring device 216 is moved to the Y-axis moving table 2.
The measuring laser beam 218,2 is attached to the length measuring mirror 217 attached to
Irradiate 19, precisely measure the position of the moving table during movement, and determine the error from the target value and the
And the amount of error is corrected by acousto-optic deflectors 207 and 208 to achieve high-speed and high-precision deflection. The desired pattern data is stored in the computer 221 and is synchronized with the deflection position through the controller 220 to operate the optical modulator 204 to obtain a desired resist latent image, electrostatic latent image and processed image.

Problems to be Solved by the Invention However, in the above-described conventional optical scanning device shown in FIG. 6, when recording or reading on a large screen is performed with a minute spot, the diameter of the incident beam becomes large. The constant-speed scanning lens 106 becomes large. Further, there is a problem that spot unevenness occurs at the center and the end in the scanning area due to the influence of the aberration generated from the constant speed scanning lens 106.

On the other hand, the conventional optical scanning device shown in FIG. 7 uses acousto-optical elements as the deflectors 207 and 208, so that blanking is small and high-speed deflection can be performed.
When scanning is performed continuously, the laser beams emitted from the deflectors 207 and 208 are diverged or converged, and a cylindrical lens must be provided to correct this. Also, when high-speed deflection is performed by the acousto-optic deflectors 207 and 208, the relationship between the voltage input to the driver of the deflectors 207 and 208 and the output frequency is not constant, and distortion occurs. The divergence and convergence angle change continuously, and the objective lens 210
As a result, there is a problem that the focal position of the laser beam condensed fluctuates, causing defocus in the scanning direction. In order to eliminate this, the driver of the deflectors 207 and 208 must be provided with a circuit for correcting distortion. Furthermore, when the deflection speed is changed, the state of the distortion changes, so that the correction circuit must be changed each time.

Therefore, the present invention solves the above-mentioned problems of the prior art, and can increase the scanning speed, can scan a large screen, and perform high-resolution drawing or reading. It is an object of the present invention to provide an optical inspection device capable of performing such operations.

Means for Solving the Problems And the technique of the present invention for solving the above problems, a light source, a collimating optical system for collimating a light beam from the light source, and collimated by the collimating optical system A deflecting optical system that deflects a light beam in a main scanning direction to perform main scanning; a reflecting optical system that propagates a light beam deflected by the deflecting optical system in a sub-scanning direction orthogonal to the main scanning direction; Having an imaging optical system that forms an image of the light beam propagated in the sub-scanning direction on the original surface by the system.
An optical scanning device that performs sub-scanning in a direction orthogonal to the main scanning direction by moving the imaging optical system in an optical axis direction.

Operation The operation of the above technical means is as follows.

That is, by scanning the laser beam deflected by the polyhedral mirror by the imaging lens moving in the optical axis direction, it is possible to perform drawing accompanied by feeding in the sub-scanning direction. Also, since only the lightweight lens is moved, the moving speed can be increased. Further, since the imaging lens is used, almost no change in off-axis aberration due to the movement of the pupil position is observed, and therefore, almost no change in the spot shape accompanying the movement of the imaging lens is observed.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

First, a first embodiment of the present invention will be described. First
1 to 3 show an optical scanning device according to a first embodiment of the present invention. FIG. 1 is a perspective view, FIG. 2 is a sectional view, and FIG. 3 is a right side view of FIG.

1 to 3, reference numeral 1 denotes a laser, 2 denotes a condenser lens for condensing a laser beam from the laser 1, 3 denotes a modulator that modulates the laser beam according to image information, and 4 denotes a modulator. A collimating lens for converting the emitted laser beam into a parallel beam of a certain size, 5 is a polyhedral mirror (polygon mirror) for deflecting the parallel beam emitted from the collimating lens 4, and 6 is a laser beam emitted from the polyhedral mirror 5 having a certain size. A Kepler-type relay lens for converting the parallel beam into a parallel beam, 7 is a reflection mirror for turning the parallel beam back, 8 is moved in the direction of the optical axis, and condenses the deflected parallel beam onto the document surface 10 for scanning. The image lens 9 is a reflection mirror that moves in the optical axis direction and turns the laser beam condensed by the imaging lens 8 back to the document surface 10.

 Next, the operation of the above embodiment will be described.

The laser beam diverged from the laser 1 forms a beam waist inside the modulator 3 and is condensed by the condenser lens 2 in order to increase the modulation speed of the laser beam, and the modulator 3 is installed at this beam waist position. Modulates the laser beam. The exit beam diverged again from the modulator 3 becomes a parallel beam of a certain size by the collimator lens 4 and exits. This exit beam is deflected by the polyhedral mirror 5,
A parallel beam of a certain size passes through the relay lens 6 and is reflected by the reflection mirror 7. The parallel beam is condensed on the original surface 10 by the image forming lens 8 using the reflection mirror 9, and recording or reading is performed while scanning. At this time, the imaging lens 8 and the reflection mirror 9 move in the optical axis direction, and feed in the sub-scanning direction.

According to the above embodiment, the scanning direction is the polyhedral mirror 5.
The recording is performed while moving the imaging lens 8 and the reflection mirror 9 in the optical axis direction, thereby eliminating the need to feed the table of the document surface 10 in the sub-scanning direction. The imaging lens 8
The reflection mirror 9 is much lighter than the table on the document surface 10, so that the moving speed can be increased. Further, since the beam incident on the modulator 3 forms a beam waist inside the modulator 3, the modulation speed can be increased. Therefore, the recording and reading speed can be increased, and a large screen can be scanned. Further, if the imaging lens 8 is only a lens group having a positive power, the change in off-axis aberration due to the movement of the pupil position is hardly observed, and therefore, the change in the spot shape due to the movement of the imaging lens 8 is hardly observed. It becomes impossible to see, and high-resolution drawing or reading can be performed.

 Next, a second embodiment of the present invention will be described.

 FIG. 4 is a sectional view showing a second embodiment of the present invention.

In the present embodiment, the same members as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted, and different points will be mainly described.

As shown in FIG. 4, a beam splitter 11 is provided between the condenser lens 2 and the modulator 3, and a multi-channel modulator 3 is used.

 Next, the operation of the above embodiment will be described.

The beam splitter 11 splits the beam condensed by the condensing lens 2 into two beams and enters the multi-channel modulators 3 respectively. Therefore, the number of spots condensed by the imaging lens 8 becomes two. By changing the focal length of the collimating lens 4, the two spots can be scanned adjacent to each other, and the scanning time can be reduced to about half. Can be shortened. At this time, if the beam splitter 11 divides the beam into more beams and makes the number of channels of the modulator 3 equal to the number of divisions, the scanning time can be further reduced.

Next, a third embodiment of the present invention will be described. FIG. 5 is a sectional view of a main part showing the embodiment of FIG. 3 of the present invention.
This embodiment shows an example of a synchronization system relating to modulation of a beam spot.

When the polyhedral mirror 5 is used for the deflector, a division error occurs, so that an error occurs at the head position of the beam spot. Therefore, in this embodiment, as shown in FIG. 4, a reflecting mirror 12 is installed at the spectral position of the Kepler-type relay lens 6, and the beam turned back by the reflecting mirror 12 enters the photodetector 14 through the lens 13. Then, a signal is generated, and this signal is used as a synchronization signal so that the cueing position of the modulator 3 can be constantly kept at a constant position. When a line sensor is used for the photodetector 14 and the line direction is set to a direction perpendicular to the deflection direction, the tilt of the polyhedral mirror 5 can be detected, and the modulator 3 can correct the tilt. Can be.

Effects of the Invention As described above, according to the present invention, a polyhedral mirror is used as a scanning method, an imaging lens is used, and drawing and reading are performed while moving the imaging lens in the optical axis direction. Therefore, the scanning speed can be increased, a large screen can be scanned, and high-quality drawing or reading can be performed.

[Brief description of the drawings]

1 to 3 show an optical scanning device according to a first embodiment of the present invention. FIG. 1 is a perspective view, FIG. 2 is a sectional view, FIG. 3 is a right side view of FIG. FIG. 4 is a cross-sectional view illustrating an optical scanning device according to a second embodiment of the present invention, FIG. 5 is a cross-sectional view of a main part illustrating the optical scanning device according to the third embodiment of the present invention,
6 and 7 are explanatory views of a conventional optical scanning device. 1 ... laser, 2 ... condenser lens, 3 ... modulator, 4 ...
... Collimate lens, 5 ... Polyhedral mirror, 6 ... Relay lens, 7 ... Reflection mirror, 8 ... Image forming lens, 9 ...
… Reflection mirror, 10… Document surface, 11… Beam splitter, 12… Reflection mirror, 13… Lens, 14… Photodetector.

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Takeo Sato 3-10-1, Higashi-Mita, Tama-ku, Kawasaki-shi, Kanagawa Prefecture Inside Matsushita Giken Co., Ltd. (72) Inventor Koichi Kawata 3-chome, Higashi-Mita, Tama-ku, Kawasaki-shi, Kanagawa No. 10 No. 1 Matsushita Giken Co., Ltd. (72) Inventor Hideharu Fukazawa 2-3-8 Shimomeguro, Meguro-ku, Tokyo Inside Matsushita Electric Transmission Co., Ltd. (72) Hiroyuki Takenouchi 2-chome, Shimomeguro, Meguro-ku, Tokyo No. 8 Inside Matsushita Electric Transmission Co., Ltd. (56) References Japanese Utility Model Sho 57-118881 (JP, U)

Claims (2)

(57) [Claims] 1. A light source, a collimating optical system for collimating a light beam from the light source, a deflecting optical system for performing main scanning by deflecting the light beam collimated by the collimating optical system in a main scanning direction, and the deflection A reflection optical system for propagating a light beam deflected by the optical system in a sub-scanning direction orthogonal to the main scanning direction, and forming an image of the light beam propagated in the sub-scanning direction on the document surface by the reflection optical system An optical scanning device, comprising: an imaging optical system; and performing sub-scanning in a direction orthogonal to the main scanning direction by moving the imaging optical system in an optical axis direction. 2. A condensing optical system for condensing a light beam from the light source between a light source and a deflecting optical system, and a modulator for modulating the light beam condensed by the condensing optical system. Has,
2. The optical scanning device according to claim 1, further comprising a relay optical system between the deflection optical system and the reflection optical system.