JPS62231227A - Optical scanner - Google Patents

Abstract

PURPOSE:To improve the efficiency of utilizing light and to permit precision scanning by providing a converging diffraction grating which makes the guided light advancing in a optical waveguide into parallel light, generates a surface acoustic wave in the optical waveguide, generates a surface acoustic wave in the optical waveguide, changes the frequency continuously, emits the deflected and guided light to the outside of the waveguide and focuses the same into an optical guide space and forming such grating of one among specific materials. CONSTITUTION:The converging diffraction grating 14 is provided on the outside of the optical waveguide 11 in order to emit the deflected and guided light 13 to the outside of the waveguide and to focus the same in the space on the outside of the waveguide. The converging diffraction grating is formed of one material among TiO2, Nb2O5, Ta2O5, Si, Ge, and a-Si. The converging diffraction grating 14 is formed by coating a positive type electron resist on the surface of the waveguide 11, depositing a thin Au film by evaporation thereon, drawing a grating pattern with electron rays, removing the thin Au film, developing the resist, depositing a Ti film thereon, lifting off Ti, and thermally oxidizing the Ti in an N2 or O2 atmosphere to form the grating of TiO2. The diffraction efficiency is thoroughly improved and the efficiency of utilizing the light of a light source is considerably improved by specifying the material of the converging diffraction grating in the above-mentioned manner.

Description

Detailed Description of the Invention (Field of the Invention) The present invention relates to an optical scanning device, and more particularly, to an optical scanning device that generates surface acoustic waves in an optical waveguide, deflects the guided light by the diffraction effect of the surface acoustic waves, and performs optical scanning. The present invention relates to an optical scanning device configured to perform the following operations.

(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. Various optical scanning reading devices are also available that scan a document with light and photoelectrically detect transmitted light, reflected light, or emitted light from the document to read images recorded on the document. ing.

In such optical scanning recording devices and optical scanning reading devices,
Conventional optical scanning devices that deflect and scan recording light or reading light two-dimensionally include: (1) A device that deflects and scans a light beam using a mechanical optical deflector such as a galvanometer mirror or a polygon mirror (rotating polygon mirror); (2) EOD (electro-optic optical deflector) and AOD (ff19
(1) A device that deflects and scans a light beam using an optical deflector using an optical deflection element, such as an optical deflector (1). A device that combines a shutter array such as a liquid crystal element array or a PLZT array with a linear light source, and Connect the drive circuit individually and depending on the image quality,
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.
Further, it has the disadvantage that mechanical durability is low and wA'MIi is troublesome. 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 device using an EOD or an AOD described in (2), there is a problem in that the device tends to be large because the light beam is waved and deflected in the same manner as described above. Especially the above EO
Since the optical deflection angle of D and AOD cannot be made large, 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 device 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, in the case of an optical scanning device using a large number of light-emitting elements arranged in parallel, there is a problem in that the light-emitting intensity of each light-emitting element varies, making it unsuitable for precision scanning.

Therefore, the guided light traveling inside the optical waveguide is converted into a surface acoustic wave (3AW:
An optical scanning system 5Ai has been considered in which the light is deflected by the angle 5LJrfaC8ACOuSt 1CWaVe) and the light is scanned by changing the angle of this deflection. This optical scanning device includes an optical waveguide formed of a material through which surface acoustic waves can propagate, an optical system that converts guided light traveling in the optical waveguide into parallel light, and a parallel light beam that travels in a direction intersecting the optical path of the guided light. means for generating a surface acoustic wave in an optical waveguide that deflects the guided light; and a drive circuit for driving the surface acoustic wave generating means to generate a surface acoustic wave whose frequency changes continuously. Such an optical scanning device has excellent durability and vibration resistance, is easy to adjust, has high light utilization efficiency, is capable of precise scanning, and can be formed in a relatively small size.

However, in the above-mentioned optical scanning device, an optical element such as a prism coupler is provided in order to emit the polarized guided light out of the optical waveguide, and furthermore, an optical element such as a prism coupler is provided to emit the deflected guided light out of the optical waveguide. Since a focusing lens is provided for focusing on the body or the document to be read, there is a problem in that sufficient miniaturization cannot be achieved. Furthermore, when using the above prism coupler, it is necessary to precisely adjust the gap between the prism bottom and the optical waveguide.
An expensive fine adjustment mechanism is required for this purpose, and the prism coupler is also expensive, so the optical scanning position of 5A is 1! ! 1
It turns out to be 11I.

Furthermore, in addition to the above-mentioned adjustment work, it is also necessary to precisely adjust the relative positions of the optical waveguide and the focusing lens, making the adjustment of the optical scanning device extremely troublesome. Since such a large amount of adjustment work is required, this type of optical scanning device has low reliability.

Furthermore, when the guided light is emitted out of the optical waveguide using the prism coupler mentioned above, the shape of the emitted light becomes a parallel light beam in the direction parallel to the prism base and a diverging light beam in the perpendicular direction. Another problem is that a special focusing lens other than a normal spherical lens is required to focus the light into a circular spot.

In general, when using the prism coupler, focusing lens, etc. mentioned above, if defects occur in these optical elements or the end face of the optical waveguide, the shape of the scanning beam spot will be affected (particularly when emitting light from the end face of the optical waveguide, this There is also the problem that a defect in the end face directly leads to a chip in the scanning beam spot), making precise scanning impossible.

(Objective of the Invention) Therefore, an object of the present invention is to provide an optical scanning device that can solve the various problems described above.

(Configuration of 51 Light) The optical scanning device of the present invention includes the above-described optical waveguide, an optical system that converts the guided light into parallel light, a surface acoustic wave generating means, and a drive circuit. A focusing diffraction grating (FGC) is installed on the surface of the optical waveguide in order to emit the polarized waveguide light outside the optical waveguide and focus it in the space outside the waveguide.
A grating coupler) is provided, and this light-collecting diffraction grating is made of TiO2, NbzOs, Taz
Os, ZrO2, CeO2, ZnS, Biz
03, Zn5e, CdS%AS2 33, AS
z Ses , As445ets 54oGea
, Sbz 83 , CdTe, 3i, Ge,
It is characterized by being formed from one of the following materials: a-Si.

(Function) The deflection of guided light by surface acoustic waves has been known for some time, but will be briefly explained here. As shown in FIG. 1, for example, interdigitated electrode pairs (IDT: Tnter
The angle (Bra
aa angle) is θ, the deflection angle δ of the guided light 13 due to the acousto-optic interaction described above becomes δ−2θ. If the wavelength and effective refractive index of the guided light 13 are λ and Ne, and the wavelength, frequency, and velocity of the surface acoustic wave 12 are A, f, and V, respectively, then 2θ−2Sin' (λ/2Ne−△)soλ /Ne·81λ·f/Ne−v, and 20, that is, δ is approximately proportional to the frequency f of the surface acoustic wave. Therefore, if the frequency of the alternating voltage applied to the electrode pair 15 is continuously changed to continuously change the frequency of the surface acoustic wave 12, the deflection angle δ will be continuously changed. Therefore, if this guided light 13 is taken out of the optical waveguide 11, the light will scan one-dimensionally.

On the other hand, the condensing diffraction grating (FGC) 14 is a diffraction grating that has bends and chirps, and is a diffraction grating that has a curve and a chirp, and is a diffraction grating that combines a plane wave in the optical waveguide 11 with a
A spherical wave having a focal point at a point in space outside the optical waveguide 11 is directly coupled. Therefore, if this condensing diffraction grating 14 is provided on the surface of the optical waveguide in the optical path of the guided wave 13 deflected as described above, the deflected light will pass through the optical waveguide 1.
1 and is focused in a space outside the optical waveguide 11.

Therefore, if the photoreceptor 31 is placed at a position where this light is focused, the photoreceptor 31 will be one-dimensionally scanned by the focused circular beam spot. Note that such a condensing diffraction grating is described in detail in, for example, IEICE technical research report MW83-88, pages 47 to 54.

By the way, when guided light is emitted out of the optical waveguide using the above-mentioned condensing diffraction grating, it is desirable to sufficiently increase the diffraction efficiency in order to increase the light utilization efficiency of the light source. The diffraction efficiency PQ from the guided light to the emitted light over the length of the diffraction grating is Pq (L)-Pq ('')[1-exp(-2α
L)]. Here, Pq (oo) is l-
+oo, the power distribution ratio to the radiation light of order q of interest (used for optical scanning), α is the radiation loss coefficient. And regarding the power distribution ratio, ΣPQ('')
-1 holds true.

As is clear from the above, in order to increase the diffraction efficiency in a diffraction grating of a certain limited length, α can be increased. However, when using a substrate made of a high refractive index material such as LiNbO3, which has traditionally been suitably used for this type of optical waveguide, it is extremely difficult to increase the above α. Therefore, the present inventors investigated how the diffraction efficiency depends on the refractive index of the grating material, and obtained the results shown in FIG. 7. The characteristics shown in FIG. 7 are the characteristics of a condensing diffraction grating formed on a Ti-diffused LiNbO3 optical waveguide with a length of 21 m in the waveguide direction. As is clear from FIG. 7, the diffraction efficiency rapidly improves as the refractive index of the diffraction grating material increases. 5i, which has been widely used as a material for this type of diffraction grating,
When using NX (refractive index 2.0), the diffraction efficiency is 20%
However, if a light-collecting diffraction grating is formed using a material with a refractive index of around 2.5, a high diffraction efficiency of about 50 to 70% can be obtained.

Therefore, in the device of the present invention, the above-mentioned high refractive index (2
, 1 or more). As a result, the diffraction efficiency is increased as described above, and the light utilization efficiency of the light source is improved. The refractive index of each of the above materials is not shown below.

Material〉 Refractive index〉 Measurement wavelength〉 Ti
O22,2~2.7 550nmTa20s
2.1~2.2 633〃Nb
205 2.1-2.3 6
33 rtZ r Oz 2
．． 1 550〃Ce 02
2.2 550〃Z
nS 2.35
550/FB i2 03
2.45 550nZ n S e
2,58
633++CdS 2.
6 600°ΔS2 S3
2,61 633#AS
2 8G3 2.89
1153#△S 4QS e ta 340 G e
1@2,28 1060Iy3 b2
S3 3,0 58
9〃CdTe 3. O5IR8i
3.5
1 RGe 4.0
1Ra-8i 3.
43 1R (Embodiments) Hereinafter, the present invention will be described in detail based on the embodiments shown in the drawings.

1 and 2 show an optical scanning v4 arrangement 10 according to a first embodiment of the invention. This optical scanning device W11
0 is applied to an optical scanning recording device as an example, and this recording device includes the optical scanning device 10, an endless belt device 30 as a sub-scanning means, and a modulation circuit 40. First, the optical scanning device 10 will be explained in detail. This optical scanning device V! Reference numeral 410 includes an optical waveguide 11 formed on an elongated substrate 16, a pair of crossed comb-shaped electrodes 15 provided at the side ends of the optical waveguide 11, and a drive circuit 17 that applies an alternating voltage to the pair of electrodes 15. , has a semiconductor laser 1B directly coupled to one end surface 11a (end surface opposite to the endless belt device 30) of the optical waveguide 11, and a laser drive circuit 20 for driving the semiconductor laser 18. A waveguide lens 19 is formed on the optical waveguide 11 at a position close to the one end surface 11a, and a curve and chirp are formed on the surface of the optical waveguide 11 at a position near the end surface 1N opposite to the one end surface 11a. A light-collecting diffraction grating 14 is formed.

In this embodiment, as an example, LtNb is used on the substrate 16.
The optical waveguide 11 is formed by using an o3 wafer and providing a Ti diffusion film on the surface of this wafer. Note that other crystalline substrates made of LiTaO3, Naphire, Si, etc. may also be used as the substrate 1G. Furthermore, the optical waveguide 11 is not limited to the Ti diffusion described above, but may also be formed by sputtering or vapor depositing other materials on the closing plate 16. Regarding optical waveguides, for example, T. Tamir (
T, Tam1r) [Integrated Optics] Jb (
Topics in Applied Physics (Top
ics in Applied Physics
) Volume 7) Springer Verlag (Spri
nger-1/'er I ag) (1975); Nishihara, Haruna, and Suhara co-authored "Optical Integrated Circuits" published by Ohmsha (1988)
5), etc., and any of these known optical waveguides can be used as the optical waveguide 11 in the present invention. However, this optical waveguide 11 is made of the above-mentioned Ti diffusion film, etc.
It must be made of a material through which surface acoustic waves (described later) can propagate.

Further, the optical waveguide may have a laminated structure of two or more layers. 1 as a particularly preferable optical waveguide in the Kinoe interlayer U.
-iNbo3-based optical waveguide; iTaO5-based optical waveguide. Here, rLiNb03-based optical waveguide" or rLiTao3LiTaO5-based optical waveguide iNbO3
Or an optical wave path consisting of L r TaO3 itself,
It means both an optical waveguide made of LfN 03 or L + TaO3 which has been subjected to appropriate treatment to increase its refractive index.

As a specific example of the latter, for example, the above Ti-diffused LtNbO3
, L I N b Q 3 in which part of li is replaced by Ti-diffused L i TaO3 protons.

The waveguide lens 19 in this embodiment is, for example, a proton exchange waveguide Fresnel lens, but such a waveguide lens 19 has a surface of the optical waveguide 11 with a 5iN
A resist obtained by depositing an X film, applying a positive electron beam resist on its surface, further depositing an Au conductive thin film on top of it, drawing a Fresnel lens pattern with an electron beam, and developing the AU thin film for peeling. Ion-etch the pattern 5
It can be formed by transferring it to an iNX film, peeling off the resist, and then performing a known proton exchange.

The condensing diffraction grating 14 is made by applying a positive electron beam resist to the surface of the optical waveguide 11, and applying Au1ll! on top of the positive electron beam resist. After depositing J and electron beam drawing of the grating pattern, AuR
1 film is removed, a Ti film is deposited after resist development, and then Ti is removed in a NzW atmosphere, a 02 atmosphere, etc. after Ti lift-off.
By thermally oxidizing T i O2, a lattice of T i O2 can be formed.

The interdigitated electrode pair 15 is formed by, for example, applying a positive electron beam resist to the surface of the optical waveguide 11, further depositing an Au conductive thin film thereon, and drawing an electrode pattern with an electron beam.
After peeling off the J thin film, development was performed, and then the Cr1il film and A
It can be formed by performing lift-off in an organic solvent after depositing the 111 film.

Note that when the substrate 16 and the optical waveguide 11 are made of a piezoelectric material, the electrode pair 15 is directly attached to the inside of the optical waveguide 11 or on the substrate 16. L, it is possible to generate the surface acoustic wave 12, but if this is not the case or if the piezoelectricity is weak, the substrate 16 or a part of the optical waveguide 11 is made of piezoelectric i! ! A film may be formed by vapor deposition, sputtering, etc., and the electrode pair 15 may be placed there.

The aforementioned semiconductor laser 18 emits a laser beam (radiation beam) 13' from one end surface (light incident end surface) 11a of the optical waveguide 11 into the optical waveguide 11. This radiation beam 13' is converted into a parallel beam 13 by a waveguide lens 19, and this beam 13 travels in the direction of the arrow in the waveguide mode within the optical waveguide 11. Note that the beam 13' is made to enter the optical waveguide 11 via a lens, coupler prism, diffraction grating (grating coupler), etc., instead of directly coupling the semiconductor laser 18 to the light incident end face 11a as described above. Good too. In particular, when a diffraction grating is used here, if it is a condensing diffraction grating formed on the surface of the waveguide, the beam 13' entering the optical waveguide 11 can be made into a parallel beam, and the waveguide lens 19 It can be replaced by However, in this embodiment, the semiconductor laser 1B is directly coupled to the light incident end face 11a, and the waveguide lens 19 is used to convert the radiation beam 13° into a parallel beam.
If this is used, the optical scanning section 10 can be extremely small and highly reliable. Furthermore, the light source that generates the scanning light is not limited to the above-described semiconductor laser 18, and other sources such as a gas laser or a solid-state laser may also be used.

When recording an image using the optical scanning recording device having the above structure, the photoreceptor 31 is moved to the first position by the endless belt device 30.
It is transported in the direction of arrow Y in the figure. and semiconductor laser 18
is driven by a laser drive circuit 20 to emit a laser beam 13', and at the same time, an alternating voltage whose frequency changes continuously is applied to the electrode pair 15 from a drive circuit 17. The laser drive circuit 20 is controlled by a modulation circuit 40 so as to change the optical output according to the image signal q3 (1, that is, the intensity of the beam 13', or the number of pulses when emitting the beam 13' in a pulsed manner). The semiconductor laser 18 is driven so as to change the pulse width and pulse width.

By applying the voltage as described above to the electrode pair 15, the surface acoustic wave 12 travels on the surface of the optical waveguide 11 in the direction of arrow B in FIG. The electrode pair 15 is connected to the surface acoustic wave 1.
2 is arranged so as to travel in a direction intersecting the optical path of the guided light (parallel beam) 13.

Therefore, the guided light 13 travels across the surface acoustic wave 12, but the guided light 13 is deflected by the surface acoustic wave 12 as described above. Since the above voltage is applied to the electrode pair 15, the surface acoustic wave 12
The frequency of the waveguide light 13 changes continuously, and as a result, the deflection angle of the guided light 13 changes continuously. The guided light 13 deflected in this way is diffracted toward the substrate 16 by the condensing diffraction grating 14 having bends and chirps, exits the optical waveguide 11, passes through the substrate 16, and passes through the obliquely cut end surface. The light is emitted to the outside of the substrate 16 from 16c (see FIG. 2). At the same time, the guided light 13 is focused to a circular spot P in the space outside the optical waveguide 11 by the action of the condensing diffraction grating 14 . As described above, since the deflection angle of the guided light 13 changes continuously, this beam spot P scans one-dimensionally in the direction of the arrow X in FIG. As mentioned earlier, the guided light 13 focused on the spot P, that is, the laser beam 1
3' is modulated according to the image signal S, so that the continuous tone image carried by the image signal S is recorded on the photoreceptor 31 by this beam spot P for one main scanning line. At the same time, the endless belt device 30 moves to the beam spot P.
The photoreceptor 31 is driven in synchronization with the scanning, and the photoreceptor 31 is moved in the direction of the arrow Y to perform sub-scanning, so that a two-dimensional image carried by the image signal S is recorded on the photoreceptor 31.

In order to synchronize the image signal S for one main scanning line with the main scanning of the beam spot P, the blanking signal sb included in this image signal @S is used as a trigger signal to control the voltage applied to the electrode pair 15. The application timing can be controlled by fIlI. Furthermore, by controlling the drive timing of the endless belt device jff30 using this planning signal sb, the main scanning and sub-scanning can be synchronized.

Here, in order to increase the light utilization efficiency of the light source such as the semiconductor laser 18, it is desired that the diffraction efficiency of the condensing diffraction grating 14 is high. Therefore, in the device of the present invention, the condensing diffraction grating 14 is formed from one of the above-mentioned refractive index materials, including T i Q2.

As mentioned above, these materials can be used to form the light-collecting diffraction grating 14.
If formed, the diffraction efficiency will be increased, and the light utilization efficiency of the light source will be improved. For example, the optical scanning device 1 having the configuration described above
0, the converging diffraction grating 14 is adjusted as described above to
When formed from iOz, a diffraction efficiency of about 50 to 70% can be obtained.

In the embodiment described above, the semiconductor laser 18 is directly modulated according to the image signal S, but the semiconductor laser #F1
A Radhe beam of a constant intensity is emitted from the semiconductor laser 18 and the optical waveguide 11 by an external modulator such as an AOM (acousto-optic optical modulator) or an EOM (electro-optic optical modulator). The laser beam may also be modulated. Furthermore, by changing the magnitude of the voltage applied to the electrode pair 15, the intensity of the light diffracted by the surface acoustic wave 12 can be changed, so the magnitude of the applied voltage is controlled according to the image signal S. By this, the guided light 1
3 can also be intensity modulated. 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 of the pulse or the number of pulses may be modulated in accordance with the image signal S.

Further, in this embodiment, a continuous tone image is recorded on the photoreceptor 31, but a black and white binary image can also be recorded by controlling the semiconductor laser 18 on and off according to the image signal. Of course it is possible.

Implementation as explained above! 11, the guided light 13 is diffracted toward the substrate 16 by the condensing diffraction grating 14, but as in the optical scanning device 50 of the second embodiment shown in FIG. The condensing diffraction grating 14 may be formed so that the light beam 13 is diffracted to the side opposite to the substrate 16 and directly emitted into the air. In addition, when a long main scanning width is required, multiple optical scanning mechanisms having the structure described above are installed in parallel on the same substrate, and each scanning line from several scanning beams is combined to form a single main scanning line. may be configured.

Next, a third embodiment of the present invention will be described with reference to FIG. 4.5. In addition, in this Figure 4.5, the first
．． Elements that are equivalent to those in Figure 2 are given the same numbers, and their explanations are omitted unless particularly necessary (hereinafter,
similar). In the optical scanning device 70 of this third embodiment,
A glass block 60 is bonded to the bottom surface 16a of the substrate 16. This glass block 60 has light reflecting layers 61a and 61b on a surface 60a on the side to be joined to the substrate 1G and on a surface 6Qb opposite to this surface 6Qa, respectively. These light reflections 1i61a, 61b are made of, for example, vapor-deposited mirrors. The condensing diffraction grating 14 made of the high refractive index material mentioned above is
It is formed so that the first-order diffracted light of the guided light 13 is diffracted toward the substrate 16 side, and the end surface 1GG of the substrate 16 opposite to the end surface 16b on the side where the semiconductor laser 18 is attached is formed obliquely so as to face upward in the figure. There is. Therefore, the diffracted light 1
3 is totally reflected at the end surface 16c and enters the glass block 60. Naturally, the oblique cut angle of the end face 16c is set to an angle that causes the above-mentioned total reflection, and a light reflecting layer 61a is formed in the area on the surface 60a of the glass block 60 where the light 13 is incident. do not have.

Light 1 entering the glass block 60 as described above
Q4wJ61b is repeatedly reflected in the darkness with the two opposing light reflections 1161a and 61b, and is emitted to the outside of the glass block 60 from the surface 60b from which the light reflection Q4wJ61b is partially removed. Therefore, in this case as well, if the photoreceptor 31 is placed at a position irradiated by the focused spot P of the light 13 emitted from the glass block 60 and the above-mentioned sub-scanning is performed, the photoreceptor 31 will be moved two-dimensionally by the spot P. The image carried by the image signal S is recorded on the photoreceptor 31. In this optical scanning device 70, since the optical path of the scanning light is folded within the glass block 60 as described above, even if the entire device including the glass block 60 is made compact, the surface acoustic waves 12 can deflect the scanning light. The optical path length from the portion to the photoreceptor 31 can be set sufficiently long, and a long main scanning width can be ensured.

Note that in order to make the length of the reflected optical path within the glass block 60 longer, and the light 1 reflected at the end surface 16c.
In order to make the light 13 enter the glass block 60 more efficiently, it is of course preferable to set the oblique cut angle of the end surface 16c so that the light 13 enters the glass block 60 at the smallest possible incident angle. Also, of course, the optical path length of the above-mentioned folded optical path needs to be set so that the light 13 exits from the glass block 60 before being focused on the spot P.

Next, a fourth embodiment of the present invention will be described with reference to FIG. In the optical scanning device 80 according to the fourth actual IM mode, the end surface 16c of the substrate 16 is cut obliquely in the opposite direction to that in the device shown in FIG. 4.5, and the glass block 60 is bonded thereto. In this case, end face 1
The diagonal angle 6c is set so that the light 13 enters the glass block 60 at the smallest possible angle of incidence. By doing so, the light (first-order diffracted light) 13 diffracted by the condensing diffraction grating 14 efficiently enters the glass block 6o, and the optical path length of the reflected optical path within the glass block 60 is set to be sufficiently long. sell.

In the optical scanning device @80 configured as above, a folded optical path is also formed within the glass block 60, and the same effect as in the device shown in FIG. 4.5 can be obtained.
You can get rid of it.

Note that the endless belt device 30 serves as the sub-scanning means.
For example, other known devices such as a rotating drum may be used. Of course, this sub-scanning means may be one that moves the photoreceptor, or one that moves the optical scanning unit 5A along the surface of the photoreceptor that is placed still. In particular, the optical scanning device of the present invention has a simple structure without any mechanically operating parts, so it can be easily moved.

The embodiment device applied to the optical scanning recording device 5A has been described above, but the optical scanning device of the present invention is not limited to such a recording device, but can also be used in the optical scanning reading device as described above. Of course, it is also possible to use the beam for two-dimensional deflection scanning.

(Effects of the Invention) As explained in detail above, the optical scanning device of the present invention performs optical scanning using a single light source.
There is no problem of variations in the emission intensity of the light source, which is seen in ED arrays, etc., and precise scanning is possible, and the light utilization efficiency of the light source is also improved. Furthermore, since the optical scanning device of the present invention performs optical scanning without using mechanical operating elements, it has excellent durability and vibration resistance. Moreover, the device of the present invention does not require a prism coupler for emitting the guided light out of the optical waveguide or a focusing lens for focusing the scanning light, so it is extremely compact, easy to adjust, and inexpensive. It becomes what is formed.

Furthermore, since the optical scanning device of the present invention uses a redundant focusing diffraction grating in order to emit the guided light out of the optical waveguide and focus it, there may be some defects in this diffraction grating. This does not affect the shape of the focused spot, making it possible to always perform precise optical scanning with a beam spot of a predetermined shape. Moreover, in the device of the present invention, by specifying the material of the light-concentrating diffraction grating, its diffraction efficiency can be sufficiently increased, and therefore the light utilization efficiency of the light source can be greatly improved.

[Brief explanation of drawings]

1 and 2 are respectively a schematic perspective view and a side view showing a first embodiment of the device of the present invention, and FIG. 3 is a schematic perspective view and a side view of a device according to a first embodiment of the present invention
4 and 5 are respectively a schematic perspective view and a side view showing a third embodiment device of the present invention, and FIG. 6 is a schematic side view showing a fourth embodiment device of the present invention.
Figure WS7 is a side view showing the embodiment device. Figure WS7 is a graph showing the relationship between the refractive index and diffraction efficiency of the material of the light-concentrating diffraction grating according to the present invention. 10.50.70.80... Optical scanning device 11...
Optical waveguide 12... Surface acoustic wave 13... Guided light 14... Focusing diffraction grating 15... Cross-comb electrode pair 16... Substrate 16a... Bottom surface of substrate 16b1c... Substrate End face of 17... Drive circuit 18... Semiconductor laser 19... Waveguide lens 20... Radical drive circuit 60... Glass block 60a, b... Glass block surface 61a, b
...Light anti-rJ4 layer P...Beam spot fart f/
T Lee

Claims (3)

[Claims] (1) an optical waveguide formed of a material through which surface acoustic waves can propagate; an optical system that converts guided light traveling in the optical waveguide into parallel light; means for generating a surface acoustic wave that deflects wave light in the optical waveguide; a drive circuit that drives the surface acoustic wave generating means to generate a surface acoustic wave whose frequency changes continuously; It consists of a light focusing diffraction grating that is formed on the surface and makes the polarized guided light exit the optical waveguide and focuses it in the space outside the optical waveguide, and the light focusing diffraction grating is composed of TiO_2, Nb_2O_5,
Ta_2O_5, ZrO_2, CeO_2, ZnS, B
i_2O_3, ZnSe, CdS, As_2S_3, A
S_2Se3, As_4_0Se_■S_4_0Ge_
■, Sb_2S_3, CdTe, Si, Ge, a-Si
An optical scanning device characterized in that it is formed from one of the following. (2) The optical scanning device according to claim 1, wherein the optical system comprises a waveguide lens or a condensing diffraction grating formed in the optical waveguide. (3) The optical scanning device according to claim 1 or 2, wherein the optical waveguide is a LiNbO_3-based optical waveguide or a LiTaO_3-based optical waveguide.