JP2003098447A - Optical modulator and optical modulation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve an on-off level ratio of output light, in an optical modulator which turns on and off the output light by switching a reflection direction of incident luminous flux. SOLUTION: A driving voltage is applied, a beam fixed at both ends is deformed by electrostatic force, and is abutted on a driving electrode 403. A corresponding part of a reflecting area on the beam has an angle to reflect the incident luminous flux in the target reflecting direction by slope parts of a recessed region, and the reflected light in the region is emitted as output light (output light on). When the driving voltage is not applied, the beam and its reflecting region are parallel to a substrate plane, and the incident luminous flux is reflected in the direction largely deviated from the target reflecting direction to produce little stray light or leaked light (output light off).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical modulator (optical switch device) that switches the reflection direction of an incident light beam to turn on and off output light.

[0002]

2. Description of the Related Art As an optical switch device utilizing electrostatic force, a device that bends a cantilever beam by electrostatic force to change the reflection direction of light and switches it, and an optical modulation system using the device have been proposed by KE Petersen in 1977. (Applied Physics Letters, Vol.31, No.8, pp521 ~ pp5
twenty three). In addition, DM Bloom et al. Have announced an element that drives a diffraction grating with electrostatic force to perform optical switching (Optics Lette
rs, Vol.7, No.9, pp688-690, Patent No. 2941952, Patent No.
No. 3016871, special table 10-510374).

Further, as an image device using the light modulation system, a device in which digital micromirror devices (generally referred to as DMD) are arranged one-dimensionally or two-dimensionally by Chibo et al. Is disclosed in JP-A-6-138403. Disclosed in.

Further, as an element structure of the above-mentioned digital micromirror device, LJ Hornbeck discloses a torsion beam type or cantilever beam type digital micromirror device (Proc. SPIE Vol.1150, pp.86-102 (198).
9)). In this device, the mirror part is used while being tilted.

Further, Japanese Patent Laid-Open No. 2000-2842 discloses an element for performing high-speed light modulation by flexibly deforming a beam with fixed ends at a cylindrical shape by Gelbert.

[0006] The optical switch using a cantilever announced by KE Petersen and the torsion beam type or cantilever beam type digital micromirror device announced by LJ Hornbeck are
It has drawbacks that it is difficult to secure the stability of the beam and the response speed cannot be increased. Also, DM Bloom et al. No. 29419
The optical switch elements shown in No. 52 and No. 3016871,
There is a drawback that the wavelength of incident light is limited. On the other hand, the element disclosed in Japanese Patent Laid-Open No. 2000-2842 by Gerbert, which has parallel voids between the electrodes and bends the fixed beams at both ends into a cylindrical shape by its electrostatic attraction, can deform at high speed. The advantage is that the response speed can be increased.

In the device disclosed in Japanese Patent Laid-Open No. 2000-2842,
When the beam (ribbon) is deformed, it is characterized in that it is bent in a cylindrical shape so as not to come into contact with the opposing electrodes, and the focal point of the reflected light is aligned with the slit portion of the stopper that is spatially arranged to allow the reflected light to pass. Since the beam is not deformed until it touches the opposing electrodes, the stop position of the beam becomes unstable at high speed operation of about 10 kHz or more, the reflected light cannot be focused enough, and the amount of passing light varies. ing. Also,
Even when the beam is not deformed, part of the reflected light from the flat beam's reflecting surface passes through the slit part of the stopper, so the S / N ratio of the reflected light in the target direction that passed (contrast ratio in video equipment ) Is reduced.

The inventors of the present application have separately proposed a higher speed optical modulator and an optical modulation method using the same. In brief, the light modulator has a fixed-end beam having a mirror provided on a substrate, and a voltage is applied between the fixed-end beam and a drive electrode opposed to the fixed beam. Is a configuration in which the fixed beams at both ends are driven by electrostatic force.
Then, in a state where no driving voltage is applied, that is, in a state where the beams fixed at both ends are parallel to the surface of the substrate, the output light is turned on by reflecting the incident light flux on the mirror surface in the intended light reflection direction. When the output light is turned off, a drive voltage is applied, and the beams fixed at both ends are deformed so as to contact the drive electrodes, and the light reflected from the mirror surface is diverted from the intended light reflection direction. However, as will be described in detail later with reference to the drawings, this optical modulator and the optical modulation method also have a problem that the S / N ratio and the contrast ratio are likely to be decreased due to stray light or leaked light when OFF. is there. Further, in order to reduce stray light or leaked light, it is necessary to form a light-shielding film on the surface of the substrate, which causes problems such as an increase in manufacturing steps of the optical modulator, an increase in cost, and a decrease in yield.

[0009]

In view of the above points, the present invention intends to provide an improved optical modulation method for obtaining a high S / N ratio and a high contrast ratio, and an improved optical modulation device therefor. To do.

[0010]

The optical modulator of the present invention comprises:
An optical modulator for switching on / off output light by switching the reflection direction of an incident light beam as described in claim 1, and having a light reflection region on the substrate facing a recessed portion formed on the substrate. Both ends fixed beams are provided, and drive electrodes are provided in the recessed portions so as to face the both ends fixed beams, and the recessed portions of the substrate for determining a specific light reflection direction for turning on the output light. It has a slope part that makes a predetermined angle to the surface,
At least a part of the drive electrode is disposed on the slope portion, and when a voltage is applied between the drive electrode and the both ends fixed beam, the both ends fixed beam is deformed by electrostatic force and the driving is performed. The output light is turned on by abutting the electrode and reflecting the incident light beam in the specific light reflection direction at the portion of the light reflection area corresponding to the inclined surface portion, and when the voltage is not applied, the light reflection area The output light is turned off by reflecting the incident light flux in a direction different from the specific light reflection direction.

Another feature of the optical modulator of the present invention is that
According to a second aspect of the present invention, a light-shielding region is formed at least in a portion of the recessed portion that does not face the fixed beam ends.

Another feature of the optical modulator of the present invention is that
The same element structure composed of the both-end fixed beams and the driving electrodes is formed in an array on the substrate, and is formed between the free ends of adjacent both-end fixed beams. That is, a film having a light-shielding property is formed on the slope portion of the recessed portion facing the gap area.

Another feature of the optical modulator of the present invention is that
The same element structure composed of the both end fixing beams and the driving electrodes is arranged in an array on the substrate, and has a light shielding property in the same region on the driving electrodes. The formation of a film.

Another feature of the optical modulator of the present invention is that
The same element structure composed of the both ends fixed beams and the driving electrodes is formed in an array on the substrate, and is formed between the free ends of the adjacent both ends fixed beams. The width of the gap region is smaller than the wavelength of the light flux having the main intensity of the incident light flux.

Further, according to a sixth aspect of the present invention, there is provided an optical modulation device according to any one of the first to fifth aspects, wherein the both ends of the optical modulation device are subjected to light reflection. It is characterized in that a light beam is made incident on a region, and the reflected light of the incident light beam in a specific reflection direction determined by the angle of the inclined surface of the recessed portion of the light modulation device is emitted as output light.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings. In addition, in order to avoid duplication of description, the same reference numerals are used for corresponding parts in each drawing.

A first embodiment of an optical modulator of the present invention and an optical modulation method using the same will be described with reference to FIGS. 1 to 4.

FIGS. 1A and 1B are views for explaining the structure of the optical modulator. FIG. 1A is a sectional view taken along the line AB, and FIG. 1B is a top view. In the figure, 401 is a substrate of silicon, optical glass, or the like, and here, a silicon substrate having a (100) plane on its surface is used. An insulating film 402 such as a silicon oxide film is formed on the substrate 401. The insulating film 402 is formed with a recessed portion (slope shape) that is non-parallel to the substrate surface and forms a non-parallel void 407 for easily causing beam deformation by making full use of lithography technology and etching technology. There is. Such a recessed portion can be formed by a lithography technique using an area gradation photomask and a dry etching technique. One slope portion A of the depressed portion (see FIG.
The right slope portion in (a) is formed at a predetermined inclination angle with respect to the plane of the substrate in order to determine a desired light reflection direction (light output direction when the optical switch is ON). The inclination angles of the other slope portion may be the same, but different angles are also allowed.

The electrode 4 is formed on the insulating film 402 in the region including the recessed portion.
03 is formed. In this example, non-parallel voids 407
The driving electrode 403 is formed on almost the entire inclined surface of the hollow portion constituting the
Are formed. The material of this electrode 403 is Al, A
Metals such as u, Ti, TiN, and Cr, conductive thin films such as ITO, and polycrystalline silicon with reduced resistance by implantation of impurities can be used, but in this embodiment, they have a relatively high melting point. It is a metal that has tolerance in the manufacturing process and has good chemical resistance.
It uses TiN.

Reference numeral 404 is a protective film having a high insulating property such as a silicon nitride film or a silicon oxide film, and plays a role of preventing the electrode 403 from coming into contact with the beam 405 and the light reflection region 406 to cause a short circuit. A pad 409 for externally applying an arbitrary potential to the electrode 403 is opened in the protective film 404. A beam 405 is formed above the plane of the substrate, which faces the recessed portion via a gap 407. One end of the beam 405 is fixed, and the other end of the beam 405 is a free end that is not fixed. Beam
405 has a light reflection area 406 on the surface. Further, a pad 408 for externally applying a potential to the beam 405 and the light reflection region 406 is provided. In addition, including the examples described below,
The light reflection region 406 on the beam 405 is not necessarily limited to a film deposited separately from the beam, and the light reflection region 406 may be integrally formed of the same material as the beam 405. Here, the beam 405
A silicon nitride film having a residual tensile stress and having a good responsiveness to deformation was used as the material of. Since the silicon nitride film has a high insulating property, an aluminum (Al) -based metal film having a high conductivity and a high light reflectivity is formed here as the light reflecting region 406.

As is apparent from FIG. 1B, the optical modulator of the present embodiment is formed by arranging the element structures (optical modulators) shown in FIG. 1A adjacent to each other on the same substrate. The recessed portion is common to each element. In other words, it is a one-dimensional light modulation element array (only two adjacent light modulation elements are shown in FIG. 1B). A light modulation array in which light modulation elements are two-dimensionally arranged can be realized by the same structure, and this is also included in the present invention.

In the optical modulator of this embodiment, the light-shielding region 501, which is one of the features of the present invention, is formed on the insulating film 402 at a position corresponding to the free end of the beam 405 of the adjacent optical modulator. Is provided. The light-shielding region 501 is formed by depositing a light-shielding film on the slope of the recessed portion facing the gap region at the free end of the beam 405 of the adjacent light modulation element and patterning it. A metal oxide film, preferably a chromium oxide film, is used as a material for forming the light shielding region 501. The metal oxide film is a thin film, has high heat resistance and good chemical resistance, and has a high light-shielding property. Therefore, it is used as a light-shielding region material formed in a relatively narrow space in a liquid crystal device or the like. Of the organic films provided. In particular, the chromium oxide film is more advantageous in that it is a thinner film and has a high light-shielding property. Since the light-shielding region 501 does not exist in the gap 407 between the electrode 403 and the beam 405, even if the light-shielding region 501 has an insulating property and a capacitance, the driving voltage for deforming the beam 405 is increased. There is no such thing.

The operation of the optical modulator of the present invention described above and the optical modulation method of the present invention using the same will be described with reference to FIG. It is obvious that the optical modulator of the second embodiment described later can be used for the optical modulation method of the present invention as well.

A light beam is incident only on the vicinity of the beam 406 as shown in the drawing through a condenser lens (not shown) and a slit. When a driving voltage is applied from the outside through the pads 408 and 409, electrostatic attraction acts between the beam 405 and the electrode 403, and
As shown in (a), the beam 405 is deformed and comes into contact with the insulating film 404 in the recessed portion, and the slope portion A for defining the intended light reflection direction of the recessed portion and the corresponding beam 405 on the beam 405. The light reflection region 406 is parallel to the portion, and the incident light flux is reflected in the target light reflection direction at that portion. The reflected light flux in the intended light reflection direction is emitted as output light directly or through the optical system 100 such as a slit or a lens. At this time, the output light is turned on (ON operation state as an optical switch).

When the drive voltage is not applied, the beam 405 is not subjected to electrostatic attraction, so that the beam 405 and the light reflection region 406 are parallel to the substrate surface as shown in FIG. 2B.
In this state, the incident light flux is reflected in the light reflection area 406 and its vicinity in a direction largely deviated from the intended light reflection direction as shown in the figure, so that the output light is turned off (OFF operation as an optical switch. Status). Since the reflection direction at this time is significantly different from the target light reflection direction, the reflection component (stray light or leakage light) in the target light reflection direction is extremely small. Thus, the level ratio (S / N ratio in the image device, contrast ratio in the video device) when the output light is ON and when the output light is OFF is significantly improved.

In order to compare with the optical modulation method according to the present invention as described above, an optical modulation method using an optical modulation device having a similar structure, which has been separately proposed by the inventors of the present application, will be described with reference to FIG. Note that FIG. 3 is simplified. In the proposed method, as shown in FIG. 3 (a), the target light reflection direction is the reflection direction when the beam 405 is parallel to the substrate surface without applying a drive voltage, and the reflected light flux in that direction is output. Used as light. This is the ON operation state. As shown in FIG. 3B, the state in which the beam 405 is deformed by applying the drive voltage is the OFF operation state. At this time, as shown by the dotted line in FIG. A considerable amount of reflected light in the intended light reflection direction due to a part of 406 or the substrate surface in the vicinity thereof is also generated, and this is output as stray light or leaked light.
There is a problem in that the level ratio of the output light when it is turned on and when it is turned off is lowered, and the S / N ratio of the image equipment and the contrast ratio of the video equipment are lowered.

As a countermeasure against this problem, as shown in a simplified form in FIG.
There is a way to set 1. However, such a light-shielding film 301
It is necessary to newly add a film forming step, a lithography step, and a microfabrication step in order to form the film, which causes an increase in manufacturing cost and a decrease in yield due to a large increase in steps. According to the present invention, the S / N ratio and the contrast ratio can be significantly improved without forming such a light-shielding film.

Up to this point, the effect of providing the light shielding region 501 has not been mentioned. Here, the effect will be described with reference to FIG. 5 (a) and 5 (b) are each a diagram schematically showing a cross section of the CD line (FIG. 1 (b)) in the OFF operation state. However, FIG. 5B shows a case where the light shielding region 501 is not provided.

When the light shielding area 601 is not arranged, as shown in FIG. 6 (b), the light beam incident on the gap area 601 of the beam 405 of the adjacent element passes through the insulating films 404 and 402 and reaches the substrate 401. Therefore, a considerable amount of unwanted reflected light flux in the gap area 601 may be generated.

On the other hand, when the light shielding area 601 is arranged, as shown in FIG. 5 (a), the light beam incident on the gap area 601 is absorbed by the light shielding area 501 and does not reach the substrate 401. The unwanted reflected light flux (stray light or leaked light) in the intended light reflection direction in the gap region 601 is greatly reduced.

By providing the light shielding region 501 in this way, stray light from the gap region between adjacent elements can also be suppressed, so that the S / N ratio in the image device and the contrast ratio in the video device can be further improved. . Further, even during the ON operation, the reflection in the intended light reflection direction from the area other than the light reflection area having the predetermined inclination angle is reduced, and the unnecessary spread of the reflected light in the intended light reflection direction is suppressed. Therefore, the effect of improving the sharpness of the image of the image device or the video device can be obtained.

A second embodiment of the optical modulator of the present invention will be described with reference to FIGS. 6 and 7. FIG. 6A is a cross-sectional view (cross section taken along the line AB) of the optical modulator, and FIG. 6B is a top view thereof. In FIG. 6, reference numerals 401 to 409 are the same as those in the above-described embodiment, and thus the description thereof is omitted. As is apparent from FIG. 6B, the light modulation device of this embodiment is also a light modulation array in which light modulation elements having the same structure are arranged one-dimensionally.

The structural feature of this embodiment is that all the driving electrodes 403 are formed as a continuous film and have a common potential. The present invention also includes a configuration in which the driving electrode 403 is independent for each element, but by integrating the electrodes 403 of all elements to a common potential as in the present embodiment, the electrode 4
It is possible to form 03 so as to entirely cover the recessed portion (that is, to cover the vicinity of the beam portion), and there is an advantage that the light shielding effect described later can be further obtained.

Another feature of the structure of this embodiment is that the electrode
That is, the film 501 having a light-blocking property is formed in the same region as 403. In this embodiment, a TiN film is used as the electrode 403, which is usually formed by the sputtering method.
Subsequent to TiN sputtering, a film 501 having a light shielding property
The Cr film that becomes the base of is formed by sputtering, and a chromium oxide film (CrO) is formed by heat treatment in an oxygen atmosphere.
Then, by patterning the electrodes at the same time, the film 501 having a light shielding property can be formed without increasing the number of steps. By doing so, the optical modulator can be manufactured at a lower cost and a higher yield.

The optical modulator of the third embodiment is an optical modulation array in which the optical modulators having the same structure are one-dimensionally arranged as described above, but the optical modulators can be arranged two-dimensionally. Such a two-dimensional light modulation array is also included in the present invention. By using such an optical modulation array, it is possible to realize an image device and a video device having a high S / N ratio (high contrast).

Another feature of the structure of this embodiment is that the width d of the gap region 601 between the free ends of the beams 405 of the adjacent elements is
That is, it is narrower than the wavelength λ of the light flux having the main intensity of the incident light flux. This will be described with reference to FIG.
FIG. 7A schematically shows how the light flux enters the clearance region 601 when the width d of the clearance region is wider than the wavelength λ of the light flux having the main intensity of the incident light flux. FIG. 7B schematically shows how the light flux enters the clearance region 601 when the width d of the clearance region is narrower than the wavelength λ of the light flux having the main intensity of the incident light flux.

Generally, light has a property that it is difficult for light to pass through a region narrower than its wavelength. Due to this property, in the case of d <λ shown in FIG. 8B, the incident light flux passing through the gap region 601 is reduced as compared with the case of d <λ shown in FIG. 8A. For example, when a semiconductor laser whose main intensity is 650 nm is used as the incident light source, by setting the gap region width d to be narrower than 650 nm, it is difficult for the incident light to pass through the gap region 601. Incident light is reduced, and unwanted reflection in the intended light reflection direction in the gap region 601 is further reduced, so that it is possible to realize an image device or a video device having a higher S / N ratio (high contrast ratio).

A method of manufacturing the light modulator of this embodiment will be described. This manufacturing method is also included in the present invention. 8A to 8G are explanatory views of a typical process, in which the right side view is a schematic top view and the left side view is a schematic cross-sectional view taken along the line AB.

FIG. 8A: Plasma CV on the silicon substrate 401
A silicon oxide film 402 is deposited by the D method, and thereafter, a photoengraving method using a photomask on which a pattern having an area gradation is formed, or a photoengraving method of thermally deforming after forming a resist pattern is used to correspond to the recessed portion 901 A resist pattern having an arbitrary film thickness is formed at the location, and then a non-parallel recessed portion 901 is formed by a dry etching method. Although the non-parallel void 407 is formed by the recessed portion 901, the inclination angle of one of the slopes is set to a predetermined inclination angle in order to define the intended light reflection direction.

FIG. 8B: Titanium nitride (TiN) film and chromium oxide (CrO) so as to cover the respective slopes of the recessed portion 901.
Form a thin film of the film. The TiN thin film is formed to a thickness of 0.1 μm by a sputtering method using Ti as a target, and a Cr film is successively formed to a thickness of 0.05 μm from the TiN film by continuous treatment in the same apparatus. After that, by heat treatment in an oxygen atmosphere,
The Cr film is a chromium oxide film (CrO), and thereafter, the electrode 403 and the light-shielding film 501 are formed by photolithography and dry etching using the same mask.
After that, as the protective film 404 of the electrode 403, a silicon nitride film is formed to a thickness of 0.2 μm by the plasma CVD method.

FIG. 8C: As a sacrificial layer for forming non-parallel voids, an organic film 902 having a thickness of 2 μm is deposited by spin coating. As the sacrificial layer, a photosensitive organic film, a non-photosensitive organic film such as a polyimide film, or an amorphous silicon film formed at a low temperature can be used.

FIG. 8D: The organic film 902 is formed by CMP (chemical mec
It is flattened by a hanical polishing technique.

FIG. 8E: A silicon nitride film is deposited to a thickness of 0.03 μm by the plasma CVD method, and patterned by photolithography and dry etching to form the beam 405.

FIG. 8 (f): An aluminum film having a thickness of 0.03 μm is deposited by a sputtering technique and patterned by photolithography and dry etching to form a light reflecting region 406 having conductivity. At this time, the light reflection area 406 also forms the area of the pad 408 outside the beam 405. After that, the pad 409 of the electrode 403 is opened by the photolithography method and the dry etching method, and at the same time, the chromium oxide film on the pad 409 is also removed by etching.

FIG. 8G: The sacrificial layer 902 formed so as to cover the recessed portion is removed from the gap region by the dry etching technique to form the non-parallel void 407. Thus, the optical modulator of the present invention is completed.

The optical modulators of the respective embodiments described above all have the same element structure arranged in an array, but a single-element optical modulator is also included in the present invention. Needless to say.

[0047]

As described above, (1) Claim 1
According to the inventions described in (1) to (6), the stray light or the leak light in the OFF state of the optical output can be reduced without forming a light shielding film for reducing the stray light or the leak light on the substrate plane of the optical modulator. In addition, it is possible to improve the ON / OFF level ratio of the output light, and thus to improve the S / N ratio in the image equipment and the contrast ratio in the video equipment, and to form such a light-shielding film. It is possible to avoid an increase in the manufacturing cost of the optical modulator and a decrease in the yield due to the increase in the number of steps. (2) In particular, according to the invention described in claims 2 to 5, stray light or leakage light when the output light is turned off is further reduced, and the output light is turned on,
It is possible to further improve the OFF level ratio, and reduce the reflection in the intended light reflection direction in areas other than the light reflection area on the slope even when it is ON, thereby suppressing unnecessary spread of the output light. The sharpness of images on devices and video equipment is improved. (3) Further, according to the invention of claim 3, even if the light-shielding region is insulative and has a capacitance, an increase in drive voltage can be avoided. (4) Further, according to the invention of claim 4, it is possible to form the light-shielding region with almost no increase in the number of manufacturing steps, and it is possible to obtain effects such as being advantageous in terms of manufacturing cost and yield of the optical modulator. .

[Brief description of drawings]

FIG. 1 is a sectional view and a top view for explaining a first embodiment of an optical modulator according to the present invention.

FIG. 2 is an explanatory diagram of the operation of the optical modulation device of the present invention and the optical modulation method of the present invention.

FIG. 3 is an explanatory diagram of an optical modulation method according to the present invention.

4A and 4B are a cross-sectional view and a top view for explaining a light-shielding film on a substrate surface for reducing stray light or leaked light.

FIG. 5 is a cross-sectional view for explaining the effect of the light shielding area.

6A and 6B are a cross-sectional view and a top view for explaining a second embodiment of the light modulation device according to the present invention.

FIG. 7 is a cross-sectional view for explaining the relationship between the width of a gap region between the free ends of adjacent fixed beam ends and the wavelength of a light beam having a main intensity of an incident light beam.

FIG. 8 is a process explanatory view for explaining an example of the method of manufacturing the optical modulation device according to the second embodiment.

[Explanation of symbols]

401 substrate 402 insulating film 403 Driving electrode 404 protective film 405 Fixed beam at both ends 406 Light reflection area 407 void 501 shaded area

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Goichi Otaka             1-3-3 Nakamagome, Ota-ku, Tokyo Stocks             Company Ricoh F-term (reference) 2H041 AA16 AB14 AC06 AZ02 AZ05

Claims (6)

[Claims] 1. A light modulator for switching on / off output light by switching a reflection direction of an incident light beam, wherein both ends fixed beam having a light reflection region on the substrate facing a recessed portion formed on the substrate. Is provided, and a drive electrode is provided in the recessed portion so as to face the both end fixing beams, and the recessed portion is provided with respect to the surface of the substrate for determining a specific light reflection direction for turning on the output light. The driving electrode has at least a part of the drive electrode disposed on the slope, and both ends of the drive electrode when the voltage is applied between the drive electrode and the fixed beam at both ends. The fixed beam is deformed by electrostatic force and comes into contact with the drive electrode, and the output light is turned on by reflecting an incident light beam in the specific light reflection direction at a portion of the light reflection region corresponding to the slope portion, When the voltage is not applied, the incident light beam is transmitted to the specific area in the light reflection area. Optical modulator, wherein turning off the output light by reflecting the different from the direction of reflection direction. 2. The light modulation device according to claim 1, wherein a light-shielding region is formed in at least a portion of the sloped portion of the recessed portion that does not face the both-end fixing beams. 3. A gap region formed between the free ends of the adjacent fixed-beams, in which the same element structure including the fixed-fixed beams and the driving electrodes is formed in an array on the substrate. 2. A film having a light-shielding property is formed on the sloped portion of the recessed portion facing to each other.
The light modulator described. 4. The same element structure composed of the both-end fixed beams and the driving electrodes is formed in an array on the substrate, and a film having a light blocking property is formed on the driving electrodes in the same region. The optical modulation device according to claim 1, wherein the optical modulation device is provided. 5. A gap region formed between the free ends of the adjacent fixed beams, wherein the same element structures including the fixed beams and the driving electrodes are arranged in an array on the substrate. 2. The optical modulator according to claim 1, wherein the width of is smaller than the wavelength of the light flux having the main intensity of the incident light flux. 6. The optical modulator according to any one of claims 1 to 5, wherein a light beam is made incident on the light reflection regions of the beam fixed at both ends of the optical modulator, and a recessed portion of the optical modulator is provided. An optical modulation method, characterized in that reflected light of the incident light flux in a specific reflection direction determined by the angle of the inclined surface is emitted as output light.