JPH065347B2 - Optical scanning device - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to an optical scanning device, and more particularly, to a plurality of optical switches arranged in parallel in an optical waveguide, and these optical switches control guided light extraction from the optical waveguide. The present invention relates to an optical scanning device configured to perform scanning.

(Prior Art) As is well known, various optical scanning type recording devices and reading devices have been conventionally provided. As an optical scanning device for one-dimensionally scanning recording light or reading light in such a device, conventionally, a mechanical optical deflector such as a galvanometer mirror or a polygon mirror (rotating polygon mirror) is used to deflect and scan a light beam. , Which deflects and scans a light beam by an optical deflector using a solid optical deflector such as EOD (electro-optical deflector) or AOD (acousto-optical deflector), shutter array such as liquid crystal element array or PLZT array and line In combination with a light source, a drive circuit is individually connected to each shutter element of the shutter array, and according to the image signal,
Line-sequential scanning by selecting ON / OFF and opening at the same time. Furthermore, a large number of light emitting elements such as LEDs are arranged side by side in a row, and a drive circuit is individually connected to each light emitting element to generate an image signal. ON /
It is known that line-sequential scanning is performed by selecting OFF and simultaneously emitting light.

However, the above mechanical optical deflector is weak against vibration,
In addition, it has the disadvantage that it has low mechanical durability and is troublesome to adjust. Further, since the light beam is swung and deflected, the optical system becomes large, which causes a problem that the recording device and the reading device are upsized.

Even in the optical scanning device using the EOD or AOD, in order to shake and deflect the light beam in the same manner as described above,
There is a problem that the device tends to be large. Especially the above EOD
Since AOD and AOD cannot have a large light deflection angle, the optical system tends to be larger than when a mechanical light deflector is used.

In the optical scanning device using one shutter array, since it is necessary to use two polarizing plates, there is a problem that the light utilization efficiency of the light source is very low.

Further, in an optical scanning device that uses a large number of light emitting elements arranged side by side, there is a problem that it is not suitable for precision scanning because the light emission intensity of each light emitting element varies.

Therefore, recently, an optical scanning device in which a large number of optical switches are arranged in parallel in an optical waveguide has been considered. In this optical scanning device, a large number of optical switches capable of emitting guided light traveling in the optical waveguide to the outside of the optical waveguide are arranged in parallel along the guided optical path, and one of these optical switches is sequentially selected. Specifically, the guided light is taken out. In this way, the light emission position from the optical waveguide changes continuously, so that the emission beam from the optical waveguide scans one-dimensionally.
Since this scanning device uses a single light source, there is no problem of light emission intensity variation of the light source found in the LED array or the like, precision scanning is possible, and light utilization efficiency of the light source is improved. Further, since this optical scanning device has no mechanical operation part, it is excellent in durability and vibration resistance and can be easily adjusted. Further, since the optical beam can be scanned without largely shaking, the optical scanning device Further, it is possible to avoid an increase in the size of the optical scanning system and form the optical scanning recording device or the reading device in a small size.

However, in the optical scanning device having the above configuration, there is a problem that the extinction ratio cannot be sufficiently increased due to the leaked light from the optical switch. This is referred to below as the number of pixels 10
An optical scanning device corresponding to 00, that is, an optical scanning device in which 1000 optical switches are arranged in parallel along a guided light path will be described in detail as an example. Here, the amount of light extracted from the optical waveguide when the optical switch is opened is Ion, and the amount of light emitted from the optical waveguide when the optical switch should be closed, that is, the amount of leaked light is Ioff. The extinction ratio of one optical switch itself is Ioff / Ion
However, in the optical scanning device having the above-described configuration, one optical switch is opened once per beam scanning, while leakage light is emitted while the other 999 optical switches are sequentially opened alternately. Therefore, the extinction ratio of the optical scanning device is 999 × Ioff · τ / (Ion · τ) = 999 × Ioff / Ion≈Ioff / Ion × 10 ³ , where τ is the open time of one optical switch. Become. Therefore, in order to put the optical scanning device into practical use, 1
If attempting to reserve a / 10 ³ extinction ratio, because it is ^{Ioff / Ion × 10 3 = 1} /10 3, Ioff / Ion = 1/10 6 i.e. extinction ratio of 1/10 ⁶ as the optical switch itself is determined Will be done. However, at present, it is extremely difficult to obtain an optical switch having such a high extinction ratio.

(Object of the Invention) The present invention has been made in view of the above circumstances, and provides an optical scanning device that is composed of an optical waveguide and an optical switch group and has a high extinction ratio and that is suitable for practical use. The purpose is to.

(Structure of the Invention) In the optical scanning device of the present invention, in the above-described optical waveguide, a plurality of optical path switching switches are arranged along the main optical path of the guided light traveling in the optical waveguide, and each optical path switching switch is provided. The traveling optical path of the guided light is selectively switched to one of the main optical path and the optical path branched from the main optical path, and a plurality of ON / OFF switches are provided so as to be paired with each of the optical path changeover switches. An optical switch is provided on the branched optical path so that the guided light traveling along the branched optical path can be arbitrarily emitted to the outside of the optical waveguide by these ON / OFF optical switches. One of the switches is set to a state in which the guided light is sequentially and selectively emitted to the outside of the optical waveguide, and the optical path changeover switch paired with the on / off optical switch set in this state is set as above. Toki state to advance the guided light in the optical path is an optical path changeover switch of the guided light traveling direction upstream side than those formed by providing a driving circuit for setting the state to advance the guided light in the main light path.

(Embodiment) Hereinafter, the present invention will be described in detail based on an embodiment shown in the drawings.

FIG. 1 shows an optical scanning device according to a first embodiment of the present invention. An optical waveguide 11 is provided on an elongated substrate 10, and a semiconductor laser 12 is directly coupled to one end surface 11a of the optical waveguide 11. And the semiconductor laser 12
In the position facing the optical waveguide 11, the waveguide lens
13 are formed. In the present embodiment, as an example, a LiNbO ₃ wafer is used as the substrate 10, and the optical waveguide 11 is formed by providing a Ti diffusion film on the surface of this wafer. A crystalline substrate made of sapphire, Si or the like may be used as the substrate 10. Also optical waveguide
11 is not limited to the above Ti diffusion, and can be formed on the substrate 10 by sputtering, vapor deposition, or the like. Regarding the optical waveguide, for example, Titamir (T.
Tamir) "Integrated Optics" (Topics in Applied Physics (Topics i
n Applied Physics Volume 7) Springer Fairlag (Springer-Verla)
g) published (1975); Nishihara, Haruna, and Suhara co-authored "Optical Integrated Circuits" published by Ohmsha (1985) and the like have detailed descriptions. In the present invention, any of these known optical waveguides is referred to as the optical waveguide 11. Can also be used. The optical waveguide may have a laminated structure of two or more layers.

The waveguide lens 13 in this embodiment is, for example, a proton exchange type waveguide lens. Such a waveguide lens 13 has a SiNx film deposited on the surface of the optical waveguide 11,
A positive electron beam resist is applied on the surface, a thin film for Au conduction is further vapor-deposited thereon, a lens pattern is drawn with an electron beam, and the resist pattern obtained by developing after peeling off the Au thin film is ion-etched to SiNx. It can be formed by transferring to a film, peeling the resist, and then performing known proton exchange.

The semiconductor laser 12 has one end face (light incident end face) 11 of the optical waveguide 11.
A laser beam (radiation beam) 14 'is emitted from a toward the inside of the optical waveguide 11. This radiation beam 14 'is made into a parallel beam 14 by the waveguide lens 13, and this beam 14 travels in the direction of arrow A in the waveguide mode in the waveguide mode.
It should be noted that the semiconductor laser 12 is not directly coupled to the light incident end face 11a as described above, but the beam 14 'is made incident into the optical waveguide 11 via a lens, a coupler prism, a diffraction grating (grating coupler), or the like. Good. In particular, when a diffraction grating is used here, if it is a converging diffraction grating formed on the surface of the waveguide, the beam 14 'that enters the optical waveguide 11 can be made into a parallel beam, and the waveguide lens 13 Can be replaced with However, if the semiconductor laser 12 is directly coupled to the light incident end face 11a and the waveguide lens 13 is used for collimating the radiation beam 14 'as in this embodiment, the optical scanning device is extremely small and reliable. Can be expensive. Further, the light source is not limited to the semiconductor laser 12 described above, but other gas sources such as a gas laser or a fixed laser may be used.

In the optical path of the parallel beam 14 (that is, the main optical path of the guided light) indicated by the arrow A, a large number of optical path change-over switches R ₁ , R ₂ , R ₃ ... R _n are arranged at predetermined intervals.
Examples of the optical path changeover switches R ₁ , R ₂ , R ₃ ... R _n include, for example, a total reflection switch that transmits or totally reflects the guided light (parallel beam) 14 according to the presence or absence of an applied voltage or a value, or the like. An electro-optical branching switch for changing the branching direction of the wave light 14, and an electro-optical grating switch for similarly non-diffracting or diffracting the guided light 14 (Bragg diffraction) are used. Thus, the traveling optical path of the guided light 14 is either the main optical path L in the direction of the arrow A or the branched optical path D ₁ branched from the main optical path L in each of the optical path changeover switches R ₁ , R ₂ , R ₃ ... R _n . , D ₂ , D ₃ ... D _n .

On / off optical switches S ₁ , S ₂ , S ₃ ... S _n are provided one by one in the middle of each of the branched optical paths D ₁ , D ₂ , D ₃ ... D _n. There is. As these on / off optical switches S _{1 to} S _n , so-called cut-off type optical switches which have been conventionally known can be used. On the surface of the optical waveguide 11, branch optical paths D ₁ , D ₂ , D ₃ ... D _n on the downstream side of the ON / OFF optical switches S _{1 to} S _{n in the} traveling direction of the guided light are respectively faced from above. , Condensing diffraction gratings G ₁ , G ₂ , G ₃ ... G _n
Is provided. These condensing diffraction gratings G _{1 to} G
_n is formed by arranging a quadratic curved grid pattern (grid pattern) in parallel in the traveling direction of the guided light 14 on the surface of the optical waveguide 11, and changing the curvature of each pattern and the pitch between patterns. Thereby, the condensing diffraction grating G ₁ ~
The light emitted from G _n is focused in the space outside the optical waveguide 11. Regarding such a converging diffraction grating, for example, the Institute of Electronics and Communication Engineers Technical Report OQC
83-84, pages 47-54. When it is not necessary to narrow the light spot due to the characteristics of the target image (when recording a continuous tone image, etc.), instead of such a condensing diffraction grating, a diffracted beam that emits a beam that is parallel or slightly diffused is emitted. A grid may be used.

FIG. 2 shows the drive circuit 21 of the optical scanning device. The operation of the optical scanning device will be described below with reference to FIG. First, the semiconductor laser 12 described above is driven, and a laser beam 14 'is emitted into the optical waveguide layer 11. The light beam 14 converted into parallel light by the waveguide lens 13 is
A main optical path L travels in the waveguide 11 in the guided mode. The voltage V from the voltage generating circuit 22 is applied to the optical path changeover switches R _{1 to} R _n.
1 , and the voltage V ₂ from the voltage generating circuit 23 is applied to the ON / OFF optical switches S _{1 to} S _n via the driver 25. The driver 25 is operated by receiving the output of the shift register 24 which operates in synchronization with a clock signal CLK, sequentially selected one by one optical path changeover switch R ₁ to R _n for applying a voltage V _1, also is the selected Optical path selector switch R ₁
~ R _n paired on / off optical switches S ₁ -S
_The voltage V ₂ is applied to _n at the same time. That is, n optical path changeover switches R _{1 to} R _n and on / off optical switches S ₁ to
S First of _n is 1 th optical path changeover switch R ₁ and ON / OFF optical switches S ₁ only each voltage V _1, V ₂ is applied, following the second optical path changeover switch R ₂ and on /
The voltages V ₁ and V ₂ are applied to only the off optical switch S ₂ , respectively. When this voltage is not applied, the optical path selector switches R _{1 to} R _n are in a state of propagating the guided light 14 to the main optical path L, but when the voltage V ₁ is applied, the branched optical paths D ₁ to R ₁ respectively. The state is switched to a state in which the guided light 14 advances to D _n . On the other hand, the on / off optical switches S _{1 to} S _n are
When no voltage is applied, the guided light 14 traveling in each of the branched optical paths D _{1 to} D _n is blocked, but when the voltage V ₂ is applied, the guided light 14 is passed. In this way, the guided light 14 that has passed through the on / off optical switches S _{1 to} S _n is emitted to the outside of the optical waveguide 11 by the diffraction action of the diffraction gratings G _{1 to} G _n , respectively. Therefore, the optical path changeover switches R _{1 to} R _n and the ON / OFF optical switches S _{1 to} S _{n to} which a voltage is applied are sequentially and selectively selected as described above, so that the first diffraction grating G is initially selected. _{From 1} to the next, from the diffraction grating G ₂ , ... After the diffraction grating G _n returns to the original and the emission position of the light 14 sequentially changes from the diffraction grating G ₁ , so that the light 14 is emitted from the optical waveguide 11. External scanning is performed in the direction of arrow X in FIG. Therefore, at the irradiation position of the light 14, for example, a photoconductor or a scanned object such as a read document
If 15 is arranged, the object to be scanned 15 receives the one-dimensional scanning of the light 14. When the scanning of the light 14 (main scanning) is performed in this manner, and the scanned object 15 is moved in the direction of the arrow Y in FIG. 1 in synchronization with the main scanning by the clock signal CLK, the sub scanning is performed. The scanned object 15 is two-dimensionally scanned by the light 14. Here, in the present embodiment, since the diffraction gratings G _{1 to} G _n are condensing diffraction gratings, the scanned object 15 is scanned by a small beam spot focused by these diffraction gratings G _{1 to} G _n . Like

In addition, the light emitting position is the diffraction grating Gn → G _n-1 → …… G ₂ → G
₁ or the diffraction grating G ₁ → G ₂ → ...
… → G _n → G _n-1 …… The optical path switching switches R _{1 to} R _n and the on / off optical switches S _{1 to} S _n are changed so as to change to G _1.
You may control the voltage application to.

When this optical scanning device is applied to an optical scanning recording device,
Directly modulate the semiconductor laser 12 based on the image signal,
Alternatively, as described above, when the light beam is made to enter the optical waveguide 11 by using the coupler prism or the like, the light beam before being made to enter the optical waveguide 11 is EOM (electro-optical light modulator) or AOM (acousto-optical light). An image can be recorded on the scanned object (photoreceptor) 15 by performing modulation based on the image signal by a modulator or the like. On the other hand, when this optical scanning device is applied to an optical scanning reading device, it is necessary to detect the emitted light, the reflected light or the transmitted light emitted from the scanned object (reading manuscript) 15 by the scanning of the light 14 by the photodetector. The image recorded on the scan object 15 can be read.

Here, the extinction ratio of the optical scanning device having the above configuration will be described. As an example, consider a device corresponding to 1000 pixels, that is, a device including 1000 optical path switching switches R and 1000 ON / OFF optical switches S. The extinction ratio of the optical path changeover switch R as a single unit is set to 1/10 ³ . When the m-th optical path switching switch Rm from the side closer to the semiconductor laser 12 is in a state of propagating the guided light 14 to the branch optical path Dm side, the branch optical path in the (m + 1) th optical path switching switch R _{m + 1} The generation of leakage light to the D _{m + 1} side is double prevented by the two optical path switching switches Rm and R _{m + 1} each having an extinction ratio of 1/10 ³ (extinction ratio 1/10).
⁶ ). Hereinafter, the generation of leakage light toward the branch optical path D side in the optical path changeover switch R is prevented in triple or quadruple direction toward the downstream side of the main optical path L in the guided light traveling direction, and the generation of leakage light from the optical waveguide 11 is further prevented. Each ON / OFF optical switch S _{m + 1} ~
Since it is prevented by S _n , it can be considered that there is substantially no leakage light in the (m + 1) th ON / OFF optical switches S _{m + 1 to} S _n . On the other hand, in the above-mentioned state, in the optical path switching switches R _{1 to} R _m-1 , which are closer to the semiconductor laser 12 than the m-th optical path switching switch Rm, the leakage light to the branched optical paths D _{1 to} D _m-1 side respectively. Occurs.
Amount of this leaked light (integrated amount) during one optical scanning
Of course is the maximum in the _first optical path changeover switch R ₁ . Therefore, it goes without saying that the on / off optical switch S ₁ ~
The leakage light amount in each of S _n is also the first ON /
It is the maximum in the off optical switch S ₁ . Leakage amount Ioff in the on / off light switch S ₁ is the amount of guided light 14 entering the optical path changeover switch R ₁ Q, the opening time of the ON / OFF optical switches S ₁ to S _n tau, ON / OFF If the extinction ratio of the optical switch S ₁ is K, then Ioff = Q × 10 ⁻³ × 999 × π · K. On the other hand, the amount of emitted light Ion when the on / off optical switch S ₁ is opened is Ion = Q × (1-10 ⁻³ ) × τ. Therefore, to achieve an extinction ratio 1/10 ³ as an optical scanning apparatus as described above, Ioff / Ion = 1/10 because it is ^3, after all the on / off light switch _{S 1} of the extinction ratio 1/10 ³ It will be sufficient if it is secured.

Each ON / OFF optical switch S ₁ during one optical scanning
Leakage amount in to S _n, since gradually reduced toward the guided light traveling direction downstream side, in order to align the extinction ratio regardless of the scanning light emitting position substantially constant, for example on / off optical switches S ₁ to S Extinction ratio of _n alone K ₁ , K ₂ , K ₃ ... K
_It suffices to set _n such that K ₁ = 1/10 ³ K ₂ = 1 / (10 ³ −1) K ₃ = 1 / (10 ³ −2): K _n = 1.

In the above embodiment, when the m-th optical path change-over switch Rm is in a state of advancing the guided light 14 to the branch optical path Dm side, the (m + 1) -th and subsequent optical path change-over switches Rm _{+ 1 to} Rm. _Although all _n are set to a state in which the guided light 14 advances to the main optical path L, at this time, the optical path changeover switches R _{m + 1 to} R _n move the guided light 14 to the branch optical paths D _{m + 1 to} D _n side. It may be set to a state where it is allowed.

Next, a second embodiment device of the present invention shown in FIG. 3 will be described. In FIG. 3, elements that are the same as those shown in FIG. 1 are given the same numbers, and explanations thereof are omitted unless otherwise necessary (the same applies below). In this second embodiment device, the condensing diffraction gratings G ₁ , G ₂ , G ₃ ... G _n provided in the device of FIG. ₁ are removed, and the respective ON / OFF optical switches S _{1 to} S _n are replaced. The guided light 14 that has passed through is emitted from the side end surface of the optical waveguide 11. In this way, the light 14 emitted from the optical waveguide 11 is focused on one point by a lens array 30 such as a photorefractive index distribution type lens array. The device of the second embodiment is different from the device of the first embodiment only in the mechanism for emitting the light 14 from the optical waveguide 11, and the extinction ratio and the like are the same as those of the device of the first embodiment.

Even in the apparatus shown in FIG. 1 described above, the condensing diffraction gratings G ₁ , G ₂ , G ₃ ... G _n are not particularly condensing diffraction gratings,
The light 14 emitted from the optical waveguide 11 may be focused by the lens array 30 as described above. Furthermore, instead of providing the lens array 30 as described above, an optical waveguide
A lens array layer may be formed on the surface or the side end surface of 11 to focus the light 14. However, if a focusing diffraction grating is used as in the device of FIG.
This is preferable because the lens array 30 and the lens array layer are not required and the structure of the optical scanning device is simplified. Further, it is not always necessary to focus the light 14 emitted from the optical waveguide 11 as described above, and in some cases, the scanned object 15 may be scanned by parallel light or diffused light.

Next, the device of the third embodiment of the present invention will be described with reference to FIGS. In this optical scanning device,
An adjacent layer 26 made of a thermo-optical material is further formed on the surface of the optical waveguide 11.
Are closely arranged. The adjacent layer 26 is formed of a transparent temperature optical material that changes the optical refractive index by heating. It should be noted that the optical waveguide is arranged so that light can travel inside the optical waveguide 11.
11, the adjacent layer 26, and the substrate 10 are each formed of a material that satisfies the relationships n ₂ > n ₁ and n ₃ of the photorefractive indexes. n ₂ and n ₃ are the optical refractive indices of the optical waveguide 11 and the substrate 10, respectively, and n ₁ is the optical refractive index of the adjacent layer 26 when it is not heated. The combination of the materials of the optical waveguide 11, the adjacent layer 26, and the substrate 10 is [Nb ₂ O ₅ : K
₃ Li ₂ Nb ₅ O ₁ : glass], (Nb ₂ O ₅ : LiN
bO ₃ : glass) and the like. The optical waveguide 11, the adjacent layer 26, and the substrate 10 each have a thickness of 0.5 to 10 as an example.
The thickness is 1 μm, 1 to 50 μm, 1 μm or more, but is not limited thereto.

Each branch optical path D ₁ , D ₂ , D ₃ ... D on the surface of the adjacent layer 26
Condensing diffraction gratings G ₁ , G ₂ , G ₃ ... G _n made of a transparent electrothermal material are provided at positions facing _n . Examples of the transparent electrothermal material include a material composed of In ₂ O ₃ and SnO ₂ . The size of the diffraction gratings G _{1 to} G _n is, for example, about 10 × 10 μm to 0.2 × 5 mm, and the distance between the diffraction gratings G _{1 to} G _n is 100 to 200 μm.
It is set to a degree. The plurality of grating elements forming each of the diffraction gratings G _{1 to} G _n are electrically connected to each other at both ends, and each of the diffraction gratings G _{1 to} G _n corresponds to the driver 25 ′ shown in FIG. It is connected.

When performing optical scanning, a current I is applied to the diffraction gratings G _{1 to} G _n from the heating power source 27 of the drive circuit 21 ′ shown in FIG. 5 to the driver 25 ′.
Shed through. The driver 25 'is similar to the driver 25 of the driver circuit 21 shown in FIG. 2, the diffraction grating G ₁ ~G _n to be alternatively voltage optical path changeover switch R ₁ to R _n paired with V ₁ is applied The heating current I is supplied only to the above. Thus, when the current I is sequentially applied to the diffraction gratings G _{1 to} G _n , the diffraction gratings G _{1 to} G _n sequentially generate heat, and the adjacent layer 26 in the portion in contact with the heat generating diffraction grating is heated, and its optical refractive index. Becomes higher. Then, the relationship between the optical index of refraction n ₂ of the optical waveguide 11 and the optical index of refraction n ₁ of the adjacent layer 26 is n in the normal state (when not heated) described above.
_From the relationship of ₂ > n ₁ , the difference (n ₂ −n ₁ ) is changed to be small, or n ₂ ≦ n ₁ is changed, and the guided light is changed.
14 so as to sufficiently interact with the diffraction grating G ₁ ~G _n, will be emitted to the outside from the diffraction grating G ₁ ~G _n. That is, in this embodiment, the diffraction grating G
₁ , G ₂ , G ₃ ... G _n also function as ON / OFF optical switches.

Regarding the fact that the guided light 14 is extracted outside the optical waveguide 11 and the adjacent layer 26 by changing the optical refractive index of the adjacent layer 26 as described above, see, for example, Japanese Patent Application No. 60-74061 by the present applicant. It is described in detail in books and the like.
Further, as shown in the specification etc., not only changing the optical refractive index of the adjacent layer 26, but also changing the optical refractive index of the optical waveguide 11, or both the optical waveguide 11 and the adjacent layer 26, The guided light 14 can be extracted from the optical waveguide 11 and the adjacent layer 26 to the outside. Further, as the material for changing the light refractive index as described above, in addition to the above-mentioned temperature optical material, an electro-optical material changing the light refractive index by an electric field, an acousto-optical material changing the light refractive index by ultrasonic waves, and a light magnetic index changing by a magnetic field. A magneto-optical material or the like can be used.

Further, as described above, in order to change the optical refractive index of the optical waveguide 11 or the adjacent layer 26, means for applying energy (diffraction gratings G _{1 to} G _{n in} the example of FIG. 4) is the branch optical path D ₁ ,
In addition to arranging so as to face D ₂ , D ₃ ... D _n from above,
For example, in a pair of electric field applying electrodes, the branched optical paths D ₁ , D ₂ , D ₃ ... D _n are arranged so as to be sandwiched from the left and right sides, or the branched optical paths D ₁ , D ₂ , D ₃ ... D _n are arranged. The portion of the adjoining layer 26 facing to can be arranged so as to be sandwiched from the left and right sides. Further, the means for applying such energy does not need to be used also as a diffraction grating for extracting guided light, and may be provided as an independent ON / OFF optical switch separately from the diffraction grating.

(Effects of the invention) As described in detail above, the optical scanning device of the present invention performs optical scanning by the optical waveguide and the optical switch group, and therefore, as described above, the precision scanning is possible and the light utilization efficiency is high,
It has excellent durability and vibration resistance, is easy to adjust, and can be further miniaturized.

In the optical scanning device of the present invention, the guided light is advanced from the main optical path of the guided light to the branch optical path through the optical path changeover switch, and an on / off optical switch for controlling the scanning light extraction is arranged in each of the branch optical paths. Therefore, so to speak, the measures to prevent the generation of leaked light are doubled by both switches, and even if a switch with a relatively small extinction ratio is used as these switches, it achieves a high extinction ratio as an optical scanning device and is practically used. It can be offered.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing a first embodiment device of the present invention, FIG. 2 is a block diagram showing an electric circuit of the above embodiment device, and FIGS. 3 and 4 are second embodiment of the present invention, respectively. Apparatus, third embodiment apparatus schematic perspective view, FIG. 5 is a block diagram showing an electric circuit of the third embodiment apparatus. 10 ... substrate, 11 ... optical waveguide 13 ... semiconductor laser, 13 ... waveguide lens 14 ... guided light, 15 ... scanning target 21, 21 '... drive circuit, 26 ... adjacent layer 30 ... lens array R ₁ to R _n ... Optical path changeover switch S _{1 to} S _n ... ON / OFF optical switch G _{1 to} G _n ... Diffraction grating, L ... Main optical path D _{1 to} D _n ... Branch optical path

Claims (2)

[Claims] 1. An optical waveguide and a main optical path of guided light that travels in the optical waveguide in parallel. The traveling optical path of the guided light is either the main optical path or an optical path branched from the main optical path. A plurality of optical path switching switches for selectively switching to, and a plurality of on / off optical switches that are paired with each of these optical path switching switches to arbitrarily emit the guided light traveling along the branched optical path to the outside of the optical waveguide, One of the plurality of on / off optical switches is sequentially and selectively set to a state in which the guided light is emitted to the outside of the optical waveguide, and the on / off optical switch set in this state is paired with the on / off optical switch. A light comprising a drive circuit that sets an optical path selector switch to allow guided light to travel to the branched optical path, and a drive circuit that sets an optical path selector switch upstream of the optical path selector in the guided light travel direction to a state in which guided light travels to the main optical path.査 apparatus. 2. An optical path change-over switch downstream of a light-path change-over switch set in a state in which the drive circuit is set to allow guided light to travel to the branched optical path, and guide light to the main optical path. The optical scanning device according to claim 1, wherein the optical scanning device is set to a state in which the optical scanning is performed.