JP2000275550A - Optical deflector and video display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the optical deflector of the video display device to obtain a large angle of deflection, deflect incident light fast, and increase in reliability. SOLUTION: Support beam parts 12a and 12b, and 13a and 13b are arranged in parallel symmetrically about a virtual line IL1 passing the center G of gravity, and laser light emitting elements X1 and X2, and X3 and X4 are provided at the positions corresponding to the beams of the support beam parts 12a and 12b, and 13a and 13b respectively and driven so as to irradiate alternate combinations of the support beam parts (12a and 13a) and support beam parts (12b and 13b) divided by the virtual line IL1 with laser light. Further, the size of a movable mirror part 14 and the position relation of the support beam parts 12a and 12b, and 13a and 13b are optimized and the elements are driven at a natural oscillation frequency to obtain a large angle of deflection and fast operation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical deflector having a torsion beam and a mirror suitable for use in, for example, a projection type video display, and to an image display using the optical deflector.

[0002]

2. Description of the Related Art As a conventional optical deflector, there has been proposed an optical deflector in which a torsion beam and a mirror are formed in a minute dimensional relationship on a silicon wafer or the like by using a semiconductor manufacturing technique or a micromechanics technique. For example, the Institute of Electrical Engineers of Japan 199
An example of such an optical deflector is introduced in the 16th Sensor Symposium / Technical Digest A3-2 "Electrostatic Torsion Mirror" in 1996. This optical deflector is an attempt to apply it to an optical system tracking servo of an optical recording / reproducing apparatus, and a mirror of several mm square corresponding to a laser beam diameter of 2 mm is applied for several mrad to 1 mm by electrostatic attraction.
The driving speed is about 1 kHz which is lower than the resonance frequency of the mirror. The mirror in the optical deflector has a hexagonal shape, and a predetermined set of opposing vertices of the hexagonal shape are supported by torsion beams arranged linearly.

On the other hand, as an image information imaging technique, an ILA which is a liquid crystal driven optical address type spatial modulation element is used.
(Image Light Amplifier Product Name Reference: Monthly LCD
intelligence 1997.11 p. 99 "ILA device for projector capable of high brightness and high definition") An element has been proposed. This ILA element needs to be written with laser light, and video information can be written by scanning the laser light whose intensity has been modulated from the back side of the ILA element in the horizontal and vertical directions using an optical deflector. It has been. It is assumed that the above-described optical deflector is used for this optical writing.

For example, SX of a computer display
When an image is projected at a resolution of the GA (Super Extended Graphics Array) class, an image obtained by forming 1280 × 1024 pixels of SXGA on an ILA element size of 2.51 inches (diagonal) is used. Therefore, the conditions for the ILA element having such a number of pixels on the optical deflector side are that the operating frequency is 60 kHz or more at the maximum, and the maximum tilt angle of the mirror is ± 15.18 degrees (horizontal deflection angle ± 7.6 degrees). And the size of the mirror surface is 1 mm square (from the beam radius R of the laser beam to be deflected R = 0.5 mm).

If the deflection angle is set to be large so as to satisfy the condition on the optical deflector side and the mirror is to be driven at high speed with a small mirror size as long as the condensed beam diameter permits, the above-mentioned electrostatic drive is required. In the type of optical deflector, it is necessary to generate a large Lorentz force by using a high voltage of several kV as a driving voltage. In order to obtain a large deflection angle without using a high voltage, a method of electromagnetically driving a mirror by Coulomb force can be considered. As an electromagnetically driven optical deflector, a "planar electromagnetic actuator" disclosed in Japanese Patent Application Laid-Open No. 8-32227 is known. The optical deflector displaces a mirror by Coulomb force generated between the static magnetic field generated by a pair of permanent magnets and an alternating magnetic field generated by a coil formed in a mirror movable section.

[0006]

However, in order to obtain a large deflection angle, the above-mentioned conventional electrostatic drive type optical deflector requires a high voltage, which is not practical. When an electromagnetically driven optical deflector is used, the following problems (1) to (4) occur. (1) A permanent magnet is used to apply a static magnetic field, and it is difficult to reduce the size of the optical deflector because the magnet is large. (2) It is necessary to assemble the integrated torsion beam and mirror part with the magnet, which requires not only manual labor and labor for alignment, but also the magnetic field of the mirror part where the coil intersects, the dispersion and the driving force are constant. No longer. (3) In order to dispose the coil on the movable part, the movable surface must be composed of the mirror reflecting surface and the coil forming surface, and the movable part becomes larger and the resonance point becomes higher as the size becomes larger. Becomes difficult. (4) It is necessary to provide coil wiring on the surface of the beam supporting the mirror part, and if processing such as wiring groove or conductive film patterning is performed, the surface properties will deteriorate and the strength will decrease, and
It becomes a factor that causes a shift in operating frequency, fatigue failure, and the like.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a highly reliable optical deflector that can deflect incident light at a high speed while obtaining a large deflection angle, and a video display device using the optical deflector. Is to provide.

[0008]

In order to solve the above-mentioned problems, according to the present invention, a support beam is provided on a virtual line IL1 passing through the center of gravity.
The laser beam emitting element is provided at a position corresponding to each beam of the support beam portion in parallel and line symmetric with respect to each other, and for each combination of beams of the support beam portion divided by the virtual line IL1. The laser light emitting elements are configured to emit light alternately so as to emit laser light.

That is, according to the present invention, there is provided a movable mirror portion having one end and the other end supported by a pair of support beams formed from a semiconductor wafer and extending from an outer peripheral support portion. In the optical deflector which deflects the incident light by displacing the movable mirror, the supporting beam for supporting the movable mirror is parallel and line-symmetric with the first imaginary line passing through the center of gravity of the movable mirror. Split and arrange
And, a laser light emitting element is provided at a position corresponding to the support beam part, and the laser light of the laser light emitting element is alternately irradiated for each combination of the beams of the support beam part divided by the first virtual line, There is provided an optical deflector characterized in that the movable mirror section is tilted and driven by utilizing a minute change due to thermal stress generated by the energy of the irradiated laser light.

According to the present invention, in a video display device for projecting an image on a screen by using a laser beam modulated by a video signal, the video display device extends from the first outer peripheral support portion and supports the movable mirror portion. The first supporting beam portion is divided and arranged so as to be parallel to and symmetrical with a first virtual line passing through the center of gravity of the movable mirror portion, and the first laser is positioned at a position corresponding to the first supporting beam portion. A light emitting element is provided, a second outer peripheral support is provided on the outer periphery of the first outer peripheral support, and a second outer peripheral support extending from the second outer peripheral support and supporting the first outer peripheral support is provided. The support beam portion is divided and arranged so as to be parallel to a second virtual line orthogonal to the first virtual line passing through the center of gravity of the movable mirror portion and to be line-symmetrical, and to correspond to the second support beam portion. A light deflecting unit provided with a second laser light emitting element at a position; The first laser light emitting elements are alternately caused to emit light at a horizontal scanning frequency so as to irradiate a laser beam for each combination of beams of the first support beam portion divided by a virtual line, and the second virtual line Driving means for alternately emitting the laser light at a vertical scanning frequency so as to irradiate a laser beam for each combination of beams of the second support beam portion divided by the following. Is provided.

In the above configuration, the supporting beam supporting the movable mirror is a virtual line passing through the center of gravity G of the movable mirror.
Each of the beams is disposed at a position that is parallel and line-symmetric with respect to IL1, and each beam is at a distance L with respect to the virtual line IL1.
It is provided only with a shift. When the laser light is emitted from the laser light emitting element to the combination side of one of the beams divided by the virtual line IL1 arranged on the straight line in such a relationship,
Thermal distortion Δε is generated on the lower surface of the beam by the energy of the laser beam, the length of the beam portion is slightly extended, and the movable mirror portion is lifted from the combined side of one beam divided by the virtual line IL1. I do. Similarly, when laser light is irradiated by the laser light emitting element on the combination side of the other beam divided by the virtual line IL1 arranged on the straight line, thermal distortion Δε is generated on the lower surface of the beam by the energy of the laser beam. The length of the beam portion is slightly extended, and acts to lift the movable mirror portion from the combination side of the other beam divided by the virtual line IL1. Therefore, by irradiating the laser beam alternately for each combination of one and the other beams divided by the virtual line IL1, the virtual line IL passing through the center of gravity G
A tilt vibration can be generated around 1.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a first embodiment of the present invention.
It is a perspective view showing appearance of an embodiment. As shown in FIG. 1, the optical deflector according to the present invention includes a mirror substrate 1 and a laser substrate 2. 2 (A) and FIG.
FIG. 2B is a perspective view showing the structure of the first embodiment of the present invention. FIG. 2A shows the mirror substrate 1 and FIG.
Indicates a laser substrate. FIG. 1, FIG. 2 (A) and FIG. 2 (B)
Are assigned the same reference numerals,
First, the configuration of the first embodiment will be described with reference to FIGS. 1, 2A and 2B.

The mirror substrate 1 is formed by subjecting a single crystal silicon wafer to fine processing by a semiconductor manufacturing technique, for example, a lithography step and an etching step. As shown in FIGS. 1 and 2A, the mirror substrate 1 has a movable mirror portion 14 and a support beam portion 1 composed of four beams.
2a, 12b, 13a, 13b and the outer peripheral support 11 are integrally provided on the same plane. Movable mirror unit 14
Are support beam portions 12a, 1 extending from the outer peripheral support portion 11.
2b, 13a, 13b, and the movable mirror unit 1
On the surface of 4, a thin film 15 for reflecting a laser beam to be deflected is formed in a mirror state.

[0014] A support beam portion 12 for supporting the movable mirror portion 14
a, 12b, 13a, and 13b are respectively disposed at positions that are parallel and line-symmetric with respect to the virtual line IL1 that passes through the center of gravity G of the movable mirror unit 14. That is, the support beam portion 12b is disposed around the imaginary line IL1 with respect to the support beam portion 12a, and the support beam portion 13b is provided with respect to the support beam portion 13a.
Are arranged, and the distances to the virtual line IL1 are all equal.

A concave portion 21 is formed in the laser substrate 2, and four laser light emitting elements X 1, X 2, X 3 and X 4, for example, of a surface emitting type are formed in the concave portion 21. 4
The formation positions of the laser light emitting elements X1, X2, X3, and X4 are determined by the support beam portions 12a, 12b,
13a and 13b. Specifically, the laser light emitting element X1 is formed directly below the support beam 12a, and the laser light emitting element X2 is formed directly below the support beam 13a. Similarly, a laser light emitting element X3 is formed directly below the support beam 12b, and a laser light emitting element X4 is formed directly below the support beam 13b. Therefore, when the semiconductor laser light emitting elements X1, X2, X3, and X4 are irradiated with laser light, as shown by broken arrows in FIGS. , 13a, 1
The laser beam reaches each lower surface side of 3b. The laser substrate 2 thus configured and the mirror substrate 1 described above
Are bonded together, for example, with an adhesive or the like, and integrated as shown in FIG. At this time, the concave portion 2 of the laser substrate 2
1 secures a space on the lower surface side of the movable mirror section 14 that does not hinder the movable mirror section 14 even when the movable mirror section 14 is tilted and displaced about a virtual line IL1 passing through the center of gravity G.

Next, the operation of the first embodiment of the present invention will be described. FIG. 3A is a front view of the mirror substrate 1 according to the first embodiment. FIG. 3B is a partially enlarged view showing an operation state of the first embodiment.
(C) and FIG. 3 (D) are side views of the mirror substrate showing an operation state of the first embodiment. In addition, FIG.
2A and 2B are denoted by the same reference numerals. As described above, the support beams 12a, 12b, 1 for supporting the movable mirror 14 are provided.
3a and 13b are arranged at positions that are parallel and symmetric with respect to the virtual line IL1 passing through the center of gravity G of the movable mirror section 14, and as shown in FIG. Each beam is provided shifted by a distance L.

In such a relationship, the laser beam emitting device (X) is provided on the side of the support beam portion 12b and the support beam portion 13b which are linearly arranged.
(3, X4), when the laser beam is irradiated,
As shown in FIG. 3B, thermal distortion Δε is generated by the energy of the laser beam on the lower surface of the support beam portion 13b and the support beam portion 13b, and the length of the beam portion is slightly extended. It acts so as to lift from the side of 12b and the support beam 13b. Thereafter, when the laser light from the laser light emitting elements (X3, X4) is turned off, the thermal distortion Δε becomes zero, and the movable mirror section 14 immediately returns to the original state. next,
Similarly to the above, when the laser beam is emitted from the laser light emitting element (X1, X2) to the support beam portion 12a and the support beam portion 13a arranged on a straight line, the support beam portion 12a and the support beam portion 1 are irradiated.
Thermal distortion occurs on the lower surface of 3a due to the energy of the laser beam, so that the length of the beam portion slightly extends, and the movable mirror portion 1
4 is lifted from the support beam portions 12a and the support beam portions 13a. When the laser light from the laser light emitting elements (X1, X2) is turned off in the same manner as described above, the movable mirror section 14 immediately returns to the original state.

Therefore, by irradiating the supporting beam portions 12b and 13b side and the supporting beam portions 12a and 13a side alternately with a laser beam, an inclination is made about the imaginary line IL1 passing through the center of gravity G. Vibration can be generated. Specifically, the movable mirror section 14 is provided with a laser light emitting element (X
(C) when the laser beam is irradiated by (3, X4).
As shown in FIG. 3 (D), when the support beam 12b and the support beam 13b are lifted up and irradiated with laser light by the laser light emitting elements (X1, X2), as shown in FIG.
It vibrates so that 2a and the support beam part 13a side may lift.

The beam portion thermally excited by the laser beam has a very small heat capacity with respect to the surface area since it has a very small size. For this reason, the cycle of the drive pulse of the laser light emitting element that irradiates the support beam portion 12b and the support beam portion 13b side and the support beam portion 12a and the support beam portion 13a side alternately is several tens of kHz.
It responds satisfactorily even at a relatively high cycle of z. Even if the dimensional change of the beam portion is minute, if the distance L from the imaginary line IL1 passing through the center of gravity G of the movable mirror portion 14 to each beam is reduced as much as possible, the relationship between the fulcrum and the working point can be obtained. Therefore, the mirror inclination angle θ (see FIGS. 3C and 3D) can be increased. Further, the cycle of the driving pulse of the laser light emitting element that irradiates the support beam portions 12b and 13b side and the support beam portion 12a and support beam portion 13a side alternately is made to coincide with the natural frequency of the movable mirror portion 14. Thereby, it is possible to more effectively vibrate. For this reason, in the actual design, the size and the natural frequency of the movable mirror section 14 and the distance L for defining the position of the beam are optimized in accordance with the driving cycle required as the optical deflector.

In the above-described first embodiment, the case where the thin film 15 for reflecting the laser light is formed on the movable mirror portion 14 has been described. May be reflected directly. In the first embodiment described above, the four laser light emitting elements X1, X2, X3, X4
Has been described just below the support beams 12a, 12b, 13a, 13b. However, an opening corresponding to the size of the movable mirror 14 is provided on the laser substrate 2 side, and the laser beam is applied to each beam from directly above. A laser light emitting element may be arranged so as to irradiate, or a laser light emitting element may be arranged so as to irradiate laser light from the side of each beam.

FIGS. 4A and 4B are perspective views showing the structure of the second embodiment of the present invention. FIG. 4A shows the mirror substrate 3, and FIG. Indicates the laser substrate 4. Note that the second embodiment is different from the first embodiment in that the second support beam portion 3 including four beams is further provided.
2a, 32b, 33a, 33b and the second outer peripheral support 3
1 and the corresponding laser light emitting elements Y1, Y2, Y3
Y4 is provided to enable biaxial deflection in the X and Y directions. Parts corresponding to those in the first embodiment described above are denoted by the same reference numerals, and description of common parts is simplified. Omitted.

As in the first embodiment, the mirror substrate 3 is formed by subjecting a single crystal silicon wafer to a semiconductor manufacturing technique, for example, a fine processing by a lithography step and an etching step. As shown in FIG. 4A, the mirror substrate 3 includes a movable mirror portion 14, first support beam portions 12a, 12b, 13a, and 13b formed of four beams.
The first outer peripheral support portion 11, the second support beam portions 32a, 32b, 33a, 33b composed of four beams, and the second outer peripheral support portion 31 are integrally provided on the same plane. First
Is supported by second support beams 32a, 32b, 33a, 33b extending from the second outer support 31.

The second support beams 32a, 32b, 33a, 33b supporting the first outer peripheral support 11 are connected to a virtual line IL2 orthogonal to a virtual line IL1 passing through the center of gravity G of the movable mirror section 14. They are arranged at positions that are parallel and line-symmetric. That is, the support beam 32a is centered on the virtual line IL2.
The support beam portion 32b is provided for the support beam portion 33a, and the support beam portion 33b is provided for the support beam portion 33a.
The distances to the virtual line IL2 are all equal.

A concave portion 41 is formed in the laser substrate 4, and eight concave portions 41, for example, surface-emitting type laser light emitting elements X1, X2, X3, X4, Y1, Y2, Y3, are formed in the concave portion 41.
Y4 is formed. Laser light emitting elements X1, X2, X
The positions where 3 and X4 are formed are positions corresponding to the first support beams 12a, 12b, 13a and 13b of the mirror substrate 3. Further, the laser light emitting elements Y1, Y2, Y3, Y4
Are formed at the second support beam portions 32a, 32b, 33
a, 33b. In particular,
A laser light emitting element Y1 is formed directly below the support beam 32a, and a laser light emitting element Y2 is formed directly below the support beam 33a. Similarly, the support beam 3
A laser light emitting element Y3 is formed immediately below 2b, and a laser light emitting element Y4 is formed immediately below the support beam 33b.
Are formed. Therefore, the laser light emitting elements X1,
When a laser beam is emitted from each of X2, X3, X4, Y1, Y2, Y3, and Y4, the first support beam portion is indicated by a broken arrow in FIGS. 4A and 4B. 12
a, 12b, 13a, 13b and second support beam 32
The laser beam reaches the lower surface of each of a, 32b, 33a, and 33b. Laser substrate 4 configured as above
And the above-mentioned mirror substrate 3 are bonded together with, for example, an adhesive or the like to be integrated to form the optical deflectors (3, 4). At this time, even when the movable mirror portion 14 is inclined and displaced around the imaginary line IL1 passing through the center of gravity G on the lower surface side of the movable mirror portion 14 and the first outer peripheral support portion 11 due to the concave portion 41 of the laser substrate 4. And the first outer peripheral support 1
Even if 1 is tilted and displaced about the imaginary line IL2 passing through the center of gravity G, a space free from any trouble is secured.

As described above, the laser beam emitting element (X3,
When the laser beam is radiated by X4), the length of the beam portion is slightly extended, and acts to lift the movable mirror portion 14 from the support beam portion 12b and the support beam portion 13b side, and the linearly arranged support is provided. Beam 12a and support beam 13
When the laser light is irradiated on the a side by the laser light emitting elements (X1, X2), the length of the beam portion is slightly elongated, and acts to lift the movable mirror portion 14 from the support beam portion 12a and the support beam portion 13a side. . Similarly, when the laser beam is emitted from the laser light emitting elements (Y3, Y4) to the support beam 32b and the support beam 33b, which are similarly arranged on a straight line, the length of the beam slightly increases, and the first beam is extended. The outer peripheral support portion 11 acts to lift the support beam portion 32b and the support beam portion 33b from the side, and the laser light emitting elements (Y1, Y2) are provided on the support beam portion 32a and the support beam portion 33a arranged linearly. When light is irradiated, the length of the beam portion is slightly elongated, and acts to lift the first outer peripheral support portion 11 from the support beam portion 32a and the support beam portion 33a.

Therefore, by irradiating the support beam portions 12b and 13b side and the support beam portion 12a and support beam portion 13a side by side with laser light alternately, vibration is caused around the virtual line IL1 passing through the center of gravity G. (See the arrow in FIG. 4A), and the laser beams are alternately applied to the support beam portions 32b and 33b side and the support beam portions 32a and 33a side. Thus, vibration (see the arrow in FIG. 4A) can be generated around the virtual line IL2 passing through the center of gravity G.

FIG. 5 is a schematic diagram showing a first application example in which the present invention is applied to a video display device. As shown in FIG. 5, a video display device as a first application example includes a video signal processing circuit 51, a laser light source 52 for projection, and the optical deflectors (3, 4) described in the second embodiment. , Screen 5
3 and a drive pulse generation circuit 54.

The video signal processing circuit 51 generates, for example, a drive output for driving a laser light source based on a luminance signal. This drive output is supplied to the laser light source 52. The laser light source 52 generates a laser output according to the drive output from the video signal processing circuit 51. Therefore, a laser light whose luminance has been modulated is output from the laser light source, and this laser light is incident on the optical deflectors (3, 4).

On the other hand, the drive pulse generation circuit 54 generates a drive pulse H oscillating at the horizontal scanning frequency,
A drive pulse / H (“/” indicates inversion of H) having a phase difference of 180 degrees with respect to the drive pulse H is generated. The drive pulse generation circuit 54 generates a drive pulse V oscillating at the vertical scanning frequency, and also outputs a drive pulse / V having a phase shifted by 180 degrees with respect to the drive pulse V.
("/" Indicates the inversion of V). The four types of driving pulses (H, / H, V, / V) generated in the driving pulse generating circuit 54 are supplied to the optical deflectors (3, 4).

The light deflectors (3, 4) are connected to the 8
Laser light emitting elements X1, X2, X3, X4, Y1, Y
2, Y3, Y4, and a laser light emitting element (X1,
X2) is supplied with the driving pulse H, and the laser light emitting elements (X3, X4) are supplied with the driving pulse / H. Further, the driving pulse V is supplied to each of the laser light emitting elements (Y1, Y2), and the driving pulse / V is supplied to the laser light emitting elements (Y3, Y4).
As a result, the movable mirror section 14 oscillates at the horizontal scanning frequency and the first outer peripheral support section 11 oscillates at the vertical scanning frequency. Therefore, the optical deflector (3,
The laser light incident on 4) is deflected at a predetermined horizontal scanning frequency and vertical scanning frequency, and is projected on a screen 53.

In the first application example described above,
Although the case where the projected image is formed in a single color has been described,
Video signal processing circuit 51 and laser light source 52 for projection
And three optical deflectors (3, 4) for signal processing corresponding to each of the RGB colors, and for deflecting the laser light of the laser light source for each of the RGB colors at a predetermined horizontal scanning frequency and vertical scanning frequency. You may make it project.

FIG. 6 is a schematic diagram showing a second application example in which the present invention is applied to a video display device. Note that FIG.
The same reference numerals are given to portions corresponding to the first application example shown in FIG. 1, and common portions are omitted for simplification of description. As shown in FIG. 6, the image display device as the second applied example is the optical deflector (3, 3) of the first applied example described above.
4) and the screen 53, the imaging lens 61 and the IL
A element 62, beam splitter 63, projection lens 6
4, a projection light lamp 65 and the like. Note that the video signal processing circuit 51, the laser light source 52, the optical deflectors (3, 4) corresponding to the first application example described above,
A drive light source unit for the ILA element 62 is constituted by the drive pulse generation circuit 54.

First, conditions for writing light to the ILA element 62 will be described. For example, the ILA element 62 is a SXGA (Super Extended Graph) of a computer display.
icsArray) class image can be projected.
It is assumed that writing is performed on the A element 62 using the optical deflectors (3, 4). SXGA resolution is 1280x
There are 1024 lines, and it is necessary to scan the luminance-modulated laser light at a frequency of 60 kHz in the horizontal direction and 60 Hz in the vertical direction.

On the other hand, the horizontal deflection angle of the writing light is as follows.
It can be obtained by equation (1). φ = N × λ / {π (D / 2)} (1) where φ: horizontal deflection angle, λ: laser wavelength, N: horizontal resolution, and D: laser beam diameter. Here, the wavelength of the substantially parallel laser light is 650 nm, the laser beam diameter is 1 mm, and (λ = 650 nm), (N = 1
(280) and (D / 2 = 0.5 mm) are substituted into the above (1), (φ = 0.53 rad = 30.35 deg) is calculated. Therefore, the deflection angle θ of the mirror is 15.18.
deg (± 7.6 °).

The distance d between the imaging lens 61 and the element imaging surface can be obtained by the following equation (2). D0 = (4 / π) × (d × λ / D) (2) where D0 is an imaging beam diameter. For an ILA element size of 2.51 inches (diagonal), it is necessary to form an image with a diameter of 40 μm, so that (D0 = 40 μm), (λ = 650 n)
By substituting m) and (D = 1 mm) into the above (2) and solving with d, (d = 48.33 mm) is calculated.

As described above, as the writing conditions by the optical deflectors (3, 4), the distance d between the imaging lens 61 and the ILA element 62 is 48.33 mm, and the operating frequency is 6 at the maximum.
0 kHz or more, and the maximum mirror tilt angle is 15.1
8deg (± 7.6 °), mirror surface size 1mm
Angle (from beam radius D / 2 = 0.5 mm). The optical deflectors (3,
4) The movable mirror section 14 and the first support beam sections 12a, 1
2b, 13a and 13b are optimized and the driving frequency 6
With the same natural frequency as 0 kHz, the eight laser light emitting elements (X1,
(X2, X3, X4, Y1, Y2, Y3, Y4), a large deflection angle can be obtained. In the above description, the horizontal scanning direction that requires high-speed driving has been described. However, optimization is similarly performed in the vertical scanning direction.

It should be noted that the driving pulse generation circuit 54
A driving pulse H oscillating at a horizontal scanning frequency of Hz is generated, and a driving pulse / H having a phase shifted by 180 degrees from the driving pulse H is generated. Further, the drive pulse generation circuit 54 generates a drive pulse V oscillating at a vertical scanning frequency of 60 Hz and generates a drive pulse / V having a phase shifted by 180 degrees with respect to the drive pulse V. The four types of driving pulses (H, / H, V, / V) generated in the driving pulse generating circuit 54 are used for the optical deflectors (3, 3).
4).

The optical deflectors (3, 4) optimized as described above are provided with eight laser light emitting elements X as described above.
1, X2, X3, X4, Y1, Y2, Y3, and Y4. A driving pulse H is supplied to each of the laser light emitting elements (X1, X2), and the laser light emitting elements (X
3, X4) is supplied with the drive pulse / H. Further, the driving pulse V is supplied to each of the laser light emitting elements (Y1, Y2), and the driving pulse / V is supplied to the laser light emitting elements (Y3, Y4). As a result, the movable mirror section 14 tilts and vibrates at a horizontal scanning frequency of 60 kHz, and the first outer peripheral support section 11 tilts and vibrates at a vertical scanning frequency of 60 Hz. Therefore, the laser light from the laser light source 52 whose luminance has been modulated is incident on the optical deflectors (3, 4) and is raster-scanned by being deflected at a horizontal scanning frequency of 60 kHz and a vertical scanning frequency of 60 Hz to form an image. Light is incident from the back side of the ILA element 62 via the lens 61. A drive voltage source 67 is connected to the ILA element 62, and video information is written by forming an image of a laser beam with a predetermined beam diameter on the photoconductive layer of the ILA element 62.

On the other hand, the projection light from the lamp 65 is incident from the front side of the ILA element 62 via the optical system 66 including a collimator lens and a filter and the beam splitter 63, and the reflected light is again reflected on the beam splitter 63 and the projection lens. The image is projected onto the screen 53 via the screen 64.

In the second application example described above,
Although the case of performing optical writing with a single color has been described, a video signal processing circuit 51, a laser light source 52 for projection,
The optical deflectors (3, 4) are provided in three systems to process signals corresponding to each of the RGB colors, and to deflect the laser light of the laser light source of each of the RGB colors at a predetermined horizontal scanning frequency and a vertical scanning frequency to produce an ILA element. The light may be incident on the screen 62, or all three systems may be provided to process each of the RGB colors, and the RGB colors may be combined on the screen 53.

In the first and second applied examples described above, the case where the optical deflectors (3, 4) capable of biaxial deflection in the XY directions described in the second embodiment are used. However, the configuration may be such that the X direction and the Y direction are respectively deflected by using two optical deflectors provided separately.

[0042]

According to the present invention, the support beam is divided and arranged at a position which is parallel and symmetric with respect to the virtual line IL1 passing through the center of gravity, and the laser beam is emitted at a position corresponding to each beam of the support beam. An element is provided. Since the laser light emitting elements emit light alternately so as to irradiate laser light for each combination of beams of the support beam section divided by the virtual line IL1, a large deflection angle can be obtained and incident light can be rapidly deflected. And reliability can be improved. Further, according to the present invention, since a mirror substrate and a laser substrate formed by a semiconductor manufacturing technique without a coil are provided, the size and weight can be dramatically reduced, and the dimensions and positional accuracy are excellent. In addition, an inexpensive optical deflector can be provided. Furthermore, in the present invention, the movable mirror portion and the support beam portion are optimized and driven at the natural frequency, so that a large deflection angle can be obtained with less power, and power saving is achieved. Becomes possible.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an appearance of a first embodiment of the present invention.

FIG. 2 is a perspective view showing the structure of the first embodiment of the present invention.

FIG. 3 is an explanatory diagram used to explain the operation of the first embodiment of the present invention.

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

FIG. 5 is a conceptual diagram showing a first application example of the present invention.

FIG. 6 is a conceptual diagram showing a second application example of the present invention.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 mirror substrate 2 laser substrate 3 mirror substrate 4 laser substrate (constituting an optical deflector together with mirror substrate) 11, 31 outer peripheral support portions 12a, 12b, 13a, 13b, 32a, 32b, 32b
3a, 33b Support beam part 14 Movable mirror part 21, 41 Concave part X1, X2, X3, X4, Y1, Y2, Y3, Y4 Laser light emitting element 51 Video signal processing circuit 52 Laser light source 53 Screen 54 Drive pulse generation circuit 61 Imaging Lens 62 ILA element 63 Beam splitter 64 Projection lens 65 Lamp

Claims (4)

[Claims] A movable mirror portion formed of a semiconductor wafer and having one end and the other end supported by a pair of support beams extending from an outer peripheral support portion, and receiving the light by displacing the movable mirror portion. In an optical deflector for deflecting light, a support beam portion for supporting the movable mirror portion is divided and arranged so as to be parallel and line-symmetric with a first virtual line passing through the center of gravity of the movable mirror portion, and A laser light-emitting element is provided at a position corresponding to the support beam, and the laser beam of the laser light-emitting element is alternately irradiated for each combination of the beams of the support beam divided by the first imaginary line. An optical deflector characterized in that the movable mirror section is tilt-driven by utilizing a minute change due to thermal stress generated by energy of laser light. 2. The method according to claim 1, further comprising: providing a second outer peripheral support on the outer periphery of the outer peripheral support, and extending from the second outer peripheral support to support the outer peripheral support. The support beam portion is divided and arranged so as to be parallel to a second virtual line orthogonal to the first virtual line passing through the center of gravity of the movable mirror portion and to be line-symmetrical, and to correspond to the second support beam portion. Providing a second laser light emitting element at a position, and irradiating the laser light of the second laser light emitting element alternately for each combination of beams of the second support beam portion divided by the second virtual line, An optical deflector configured to tilt-drive the outer peripheral supporting portion using a minute change due to thermal stress generated by the energy of irradiated laser light. 3. A video display device for projecting an image on a screen using a laser beam modulated by a video signal, wherein the first support beam extends from the first outer peripheral support portion and supports the movable mirror portion. First passing through the center of gravity of the movable mirror part
The first laser light emitting element is provided at a position corresponding to the first support beam portion, and the second laser light emitting element is provided on the outer periphery of the first outer peripheral support portion.
And a second support beam portion extending from the second outer peripheral support portion and supporting the first outer peripheral support portion is connected to a first virtual line passing through the center of gravity of the movable mirror portion. A light deflecting unit that is divided and arranged so as to be parallel to and symmetrical with a second virtual line orthogonal to the second virtual beam, and that a second laser light emitting element is provided at a position corresponding to the second support beam; The first laser light emitting elements are alternately caused to emit light at a horizontal scanning frequency so as to irradiate a laser beam for each combination of the beams of the first support beam portion divided by one virtual line; Driving means for alternately emitting the second laser light emitting element at a vertical scanning frequency so as to irradiate a laser beam for each combination of the beams of the second support beam portion divided by a virtual line. An image display device characterized by the above-mentioned. 4. The optical addressing spatial modulation element according to claim 3, further comprising an optical addressing spatial modulation element, wherein the laser beam modulated by the video signal is deflected by the optical deflecting means and connected from one side of the optical addressing spatial modulation element. An image display device, wherein image information is written by image formation, and projection light is emitted from the other side of the address type spatial modulation element to obtain a projection image from the reflected light.