JPS61232427A - Optical scanning and recording device - Google Patents

Abstract

PURPOSE:To improve durability and oscillation resistance and to permit easy adjustment by providing an auxiliary scanning means which moves relatively a photosensitive body and optical waveguide and a modulating means which modulates the light made incident on the optical waveguide from a light source according to an image signal. CONSTITUTION:The exit position of a focusing beam 18 from the optical waveguide 12 moves as a surface acoustic wave 30 moves and therefore the focusing spot P of the beam 18 moves in the arrow X direction parallel with the progressing direction A of the surface acoustic wave 30 so as to scan one-dimensionally the photosensitive body 21. Since the beam 18 is intensity-modulated according to the image signal S, the image of continuous mode carried by the image signal S is recorded by as much as one main scanning line. The main scanning of the beam 18 can be synchronized with the image signal S for one main scanning line simply by using a blanking signal Sb contained in the image signal S as a trigger signal and controlling the timing for applying a voltage to an electrode pair 13. The main scanning can be synchronized with the auxiliary scanning by controlling the timing for driving an endless belt device 22 by such blanking signal Sb. The durability and oscillation resistance are thereby improved and the adjustment is made easy.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of the Invention) The present invention relates to an optical scanning recording device, and more particularly to an optical scanning recording device, in which a surface acoustic wave is generated in an optical waveguide, and a coupling effect between a diffraction grating created by the surface acoustic wave and the guided light is provided. The present invention relates to an optical scanning recording device that performs optical scanning using.

(Prior Art) As is well known, various optical scanning recording apparatuses have been conventionally provided which scan a photoreceptor with light and record a continuous tone image or a black and white binary image on the photoreceptor. Conventionally, as an optical scanning device that scans the recording light one-dimensionally in such a recording device, there is a device that deflects and scans the optical beam using a mechanical optical deflector such as a galvanometer mirror or a polygon mirror (rotating polygon mirror). , ■ A device that deflects and scans a light beam using an optical deflector using an optical deflection element such as an EOD (electro-optic optical deflector) or an AOD (acousto-optical optical deflector), ■ A shutter array such as a liquid crystal element array or a PLZT array, etc. In combination with a line light source, a drive circuit is individually connected to each shutter element of the shutter array, and according to the image signal,
0N10FF are selected and opened at the same time to perform line sequential scanning.Furthermore, a large number of light emitting elements such as LEDs are arranged in parallel in a row, and a drive circuit is individually connected to each light emitting element to respond to image signals. Te0N1
There are known devices that perform line-sequential scanning by selecting 0FF and emitting light at the same time.

However, the mechanical optical deflector described in ■ above is weak against vibrations.
It also has the drawbacks of low mechanical durability and troublesome adjustment. Furthermore, since the optical system is large in order to swing and deflect the light beam, there is also the problem that the recording device and the reading device become larger.

Furthermore, even in the case of an optical scanning recording apparatus using an EOD or an AOD (2), since the light beam is swung and deflected in the same way as described above, there is a problem that the device 2 tends to be large. In particular, since the EOD and AOD mentioned above cannot have a large optical deflection angle, the optical system tends to be even larger than when using a mechanical optical deflector (2).

On the other hand, in the case of the optical scanning recording apparatus using the shutter array (2), since it is necessary to use two polarizing plates, there is a problem in that the light utilization efficiency of the light source is extremely low.

Furthermore, the optical scanning recording device using a large number of light emitting elements arranged side by side (2) has the problem that it is not suitable for precise scanning because the light emitting intensity of each light emitting element varies.

(Object of the Invention) The present invention was made in view of the above circumstances, and has excellent durability and vibration resistance, easy adjustment, high light utilization efficiency, precision scanning, and small size. It is an object of the present invention to provide an optical scanning recording device that can be formed in the following manner.

(Structure of the Invention) The optical scanning recording device of the present invention uses a surface acoustic wave (SAW: 3u
a leading waveguide formed of a material capable of propagating rface acoustic waves; a light source that enters light into the optical waveguide from the light incident end face; and a surface acoustic wave that propagates along the optical path of the light in the optical waveguide. a drive circuit that periodically applies a pulse-like voltage to the surface acoustic wave generating means, and a coupling effect between the guided light and the diffraction grating created by the surface acoustic wave to generate a wave outside the optical waveguide. sub-scanning means for relatively moving the optical waveguide and a photoreceptor placed at a position to be irradiated with the light emitted from the light source in a direction substantially perpendicular to the traveling direction of the surface acoustic wave; and a modulation means for modulating the light incident on the image signal according to the image signal.

(Function) The diffraction grating created by the surface acoustic waves has a periodic structure of refractive index change due to the photoelastic effect of the surface acoustic waves, a periodic structure of geometric deformation of the leading waveguide surface in contact with an air layer, a ferroelectric In the medium, this can be obtained by a periodic structure in which the refractive index changes due to an electro-optic effect (which is caused by an electric field due to a piezoelectric effect) or a combination of these. The emission position of the light emitted from this surface acoustic wave portion to the outside of the optical waveguide naturally changes as the surface acoustic wave advances, so the light emitted from the leading waveguide is scanned one-dimensionally. Become.

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

The figure shows an optical scanning recording device according to one embodiment of the present invention. As shown in the figure, the optical scanning unit 10 of this optical scanning recording device includes an elongated substrate 11, a leading waveguide 12 formed on the substrate 11, and a cross-comb shaped waveguide provided at one end of the leading waveguide 12. Electrode pair (IDT: Inter
Diaital TransdtJcer) 13 and
It consists of a drive circuit 14 that applies a voltage to this electrode pair 13, and a cylindrical lens 15 arranged above the leading waveguide 12 in the figure. In this embodiment, as an example, an LtNbO3 wafer is used as the substrate 11, and the optical waveguide 12 is formed by providing a Ti diffusion film on the surface of this wafer. Note that other crystalline substrates made of sapphire, 3i, etc. may also be used as the substrate 11. Furthermore, the guiding waveguide 12 is not limited to the above-mentioned T1 diffusion.
Other materials can also be formed on the substrate 1 by sputtering, vapor deposition, or the like. Regarding the leading wavepath, for example, T,
Tam1 rlirInterarated 0pti
csJ (Topics in Applied
Physics Volume 7) Spr i nQer
-yer I aQ (1975): Detailed descriptions can be found in published works such as ``Optical Integrated Circuits'' co-authored by Hara, Kage, and Kashiwara, published by Ohmsha (1985), and in the present invention, these known optical waveguides are used as the optical waveguide 12. Either wave path can be used. However, this guide wave path 12 must be formed of a material through which surface acoustic waves (described later) can propagate, such as the above-mentioned TiEl & film.

Further, the guiding waveguide may have a laminated structure of two or more layers.

The end face of the optical waveguide 12 on the side where the electrode pair 13 is provided is a light incidence end face 12a, and this light incidence end face 12a includes:
A semiconductor laser 16 that emits a laser beam 18' into the optical waveguide 12 is directly coupled.

A waveguide lens 1γ is provided in the leading waveguide 12 at a position close to and facing the semiconductor laser 16, and the laser beam 18' emitted from the semiconductor laser 16 is
is made into a parallel beam 18 by this waveguide lens 17. This parallel beam 18 travels in the direction of the arrow in the figure in a waveguide mode within the optical waveguide 12.

Note that the semiconductor laser 16 is connected to the light incident end face 12a as described above.
The beam may be made to enter the optical waveguide 12 through a lens, a coupler prism, a grating coupler (diffraction grating), etc., instead of being directly coupled to the optical waveguide 12 . Furthermore, the light source that generates the scanning light is not limited to the above-described semiconductor laser 16, but other sources such as a gas laser or a solid laser may also be used.

A laser drive circuit 19 that drives the semiconductor laser 16 is controlled by a modulation circuit 20, and drives the semiconductor laser 16 so as to change the optical output according to the image signal S. Further, above the cylindrical lens 15, an endless belt device 22 as a sub-scanning means is disposed, and the endless belt device 22 transports the photoreceptor 21 in the direction of the arrow Y perpendicular to the traveling direction A of the parallel beam 18. It is now possible to do so.

When recording an image on the photoreceptor 21, the semiconductor laser 1
6 is driven to change the optical output according to the image signal S, as described above. At the same time, a predetermined pulse voltage is periodically applied to the electrode pair 13 by the drive circuit 14 . When a pulsed voltage is thus applied to the electrode pair 13, a group of surface acoustic waves 30 are generated in the optical waveguide 12, and these surface acoustic waves 30 propagate on the surface of the optical waveguide 12 in the direction of the arrow, that is, the beam 18. progresses in parallel. This J:
When such a surface acoustic wave 30 is generated, a diffraction grating is obtained by the photoelastic effect of the surface acoustic wave 30, the geometric deformation of the surface of the optical waveguide 12 in contact with the air layer, the electro-optic effect derived from the piezoelectric effect, or a combination of these. The beam 18 traveling through the optical waveguide 12 is emitted from the surface acoustic wave 30 to the outside of the optical waveguide 12 due to the coupling effect with this diffraction grating.

In this embodiment, the drive circuit 14 applies a voltage to the electrode pair 13 so that multiple waves of the surface acoustic waves 30 change their frequencies one after another and a surface acoustic wave 30 having a part of the so-called chirp period is obtained. The beam 18 emitted from the surface acoustic wave 30 having a part of the chirp period is focused on the front or rear side in the traveling direction of the surface acoustic wave 30. The beam 18 thus focused is further focused by the cylindrical lens 15 in a direction perpendicular to the direction of the above-mentioned focusing, and is finally focused on one spot P. Since the exit position of the focused beam 18 from the optical waveguide 12 naturally moves with the progress of the surface acoustic wave 30, the focused spot P of the beam 18
also moves in the direction of arrow X parallel to the traveling direction A of the surface acoustic wave 30, and scans the photoreceptor 21 one-dimensionally (main scan). Since this beam 18 is intensity-modulated according to the image signal S as described above, the continuous tone image carried by the image signal S is transmitted to the photoreceptor 21 by one main scanning line. recorded.

At the same time, the endless belt device 22 is driven in synchronization with the scanning of the beam 18, and the photoreceptor 21 is transported in the direction of arrow Y to perform sub-scanning.
1, a two-dimensional image carried by the image signal S is recorded.

In order to synchronize the image signal S for one main scanning line with the main scanning of the beam 18, the blanking signal @Sb included in this image signal S is used as a trigger signal, and the electrode pair 1
It is only necessary to shift the timing of voltage application to 3 by control j. Also, due to this blanking signal @Sb, endless belt installation @2
By controlling the drive timing of No. 2, it is possible to synchronize the main scanning and sub-scanning.

Note that in this embodiment 1A, the semiconductor laser 16 is directly modulated according to the image signal S, but the semiconductor laser 1
A laser beam of a constant intensity is emitted from the semiconductor laser 16 and the optical waveguide 12, and an external modulation device such as an AOM (acousto-optic modulator) or an EOM ('! aero-optical modulator) is inserted between the semiconductor laser 16 and the optical waveguide 12. The laser beam may be modulated by a device. Further, the modulation method is not limited to the intensity modulation of the laser beam, and the laser beam may be emitted in a pulsed manner, and the width or number of pulses may be modulated in accordance with the image signal S. Roughly speaking, in this embodiment, a continuous tone image is recorded on the photoreceptor 21, but the semiconductor laser 16 is turned on and off in accordance with the image signal. Of course, it is also possible to record 21 black and white images by doing this.

In the optical scanning section 10 of the embodiment described above, the end of the optical waveguide 12 on the side where the electrode pair 13 is provided is the light incident end surface 12a, and therefore the traveling direction of the beam 18 that travels within the optical waveguide 12 is Although the surface acoustic waves 30 are designed to travel in the same direction, the light incident end surface 12a is connected to the electrode pair 1.
3 on the end face opposite to the installation part, or set the electrode pair 13 on the end face opposite to the light incident end face 12a,
The traveling direction of the beam 18 and the traveling direction of the surface acoustic wave 30 may be opposite to each other. In short, if at least a portion of the surface acoustic wave 30 travels along the optical path of the beam 18, the beam 18 can be directed to the optical waveguide 12.
It can be emitted outside.

Furthermore, in the optical scanning unit 10 of the above embodiment, the surface acoustic wave 30 is a surface acoustic wave with a part of a chirp period; It may be made to occur. Of course, a diffraction grating effect can be obtained with such surface acoustic waves, so
It is possible to emit the light traveling within the optical waveguide 12 to the outside of the leading waveguide 12.

When using such surface acoustic waves that are part of a single period, the above-mentioned focusing effect cannot be obtained, so instead of the cylindrical lens 15, a lens array such as a selfoc lens array or the like may be used. , a focusing optical system in which small convex lenses are arranged in a row in the optical scanning direction;
Alternatively, a focusing optical system in which graded refractive index lenses are arranged in a row may be used. Note that when the substrate 11 and the optical waveguide 12 are made of a piezoelectric material, the electrode pair 13 can generate the surface acoustic wave 30 even if it is installed directly inside the leading waveguide 12 or on the substrate 11. If this is not the case, a piezoelectric thin film made of, for example, ZnO may be formed on a part of the substrate 11 or the guiding waveguide 12 by vapor deposition, sputtering, etc., and the electrode pair 13 may be placed there.

Further, the endless belt device 22 serves as a sub-scanning means.
However, the present invention is not limited to this, and a known device such as a rotating drum may be used. Of course, although this sub-scanning means moves the photoreceptor, it may also move the optical scanning section 10 along the surface of the document placed still. In particular, in the device of the present invention, a simple optical scanning section without mechanically operating parts is used, so that the optical scanning section can be easily moved.

In general, the optical scanning recording device of the present invention may be formed by arranging a plurality of optical scanning sections in parallel to simultaneously scan a plurality of beams of light. For example, if three optical scanning units are arranged side by side, each one has R,
It is also possible to use a combination of different color filters such as G and B or light sources of different emission colors to record a color image.

(Effects of the Invention) As explained in detail above, the optical scanning recording device of the present invention performs optical scanning using a single light source, so it is possible to reduce the variation in the light emission intensity of the light source seen in the LED array, etc. There is no problem, precise scanning becomes possible, and the light utilization efficiency of the light source is also increased. Furthermore, since the optical scanning recording device of the present invention performs optical scanning using a simple optical scanning unit that does not include mechanically operating parts, it has excellent durability and vibration resistance, and is easy to adjust. Since scanning can be performed without shaking the optical system significantly, the optical scanning system can be made smaller without increasing its size.

[Brief explanation of the drawing]

The figure is a schematic diagram showing an optical scanning recording device according to an embodiment of the present invention. 10... Optical scanning section 11... Substrate 12
... Optical waveguide 12a ... Light incidence end face 13 ... Electrode pair 14 ... Drive circuit 16 ... Semiconductor laser f18 ... Light beam 20 ...
Modulation circuit 21...Photoreceptor 22...Endless belt device 30...Surface acoustic wave and fee amendment at the same time (voluntary) Procedural amendment Commissioner of the Patent Office May 1985
Month 981, incident display
-Patent Patent Application No. 60-74066 2, Name of the invention Optical scanning recording device 3, Relationship with the case of the person making the amendment Patent applicant Location 210 Nakanuma, Minamiashigara City, Kanagawa Prefecture Name Name
Fuji Photo Film Co., Ltd. 4, Agent: 7th floor, Uraya Building, 5-2-1 Roppongi, Minato-ku, Tokyo (7318) Patent attorney: Yanagi 1) Seishi (and 1 other person) 5
(No date of amendment order, no change in content) 9. Attached documents

Claims (6)

[Claims] (1) an optical waveguide formed of a material through which surface acoustic waves can propagate; a light source that allows light to enter the optical waveguide; A driving circuit that periodically applies a pulse-like voltage to the surface acoustic wave generating means; and a coupling effect between the guided light and the diffraction grating formed by the surface acoustic wave to emit the wave out of the optical waveguide. sub-scanning means for relatively moving the optical waveguide and a photoreceptor placed at a position where the light is irradiated in a direction substantially perpendicular to the traveling direction of the surface acoustic wave; An optical scanning recording device comprising modulation means that modulates incident light according to an image signal. (2) The optical scanning recording apparatus according to claim 1, wherein the drive circuit is formed to generate a group of surface acoustic waves with a chirp period. (3) The optical scanning recording device according to claim 1, wherein the drive circuit is formed to generate a group of surface acoustic waves with a single period. (4) Optical scanning according to any one of claims 1 to 3, characterized in that the surface acoustic wave travels in the same direction as the light in the optical waveguide. Recording device. (5) Optical scanning recording according to any one of claims 1 to 3, wherein the surface acoustic wave is configured to travel in a direction opposite to the light in the optical waveguide. Device. (6) The optical scanning recording device according to any one of claims 1 to 5, further comprising a focusing optical system that focuses the light emitted from the optical waveguide.