JP2003005100A - Optical modulator and projection device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new optical modulator using an element to deflect light by vibrating mirrors as a galvano-mirror. SOLUTION: The optical modulator 110 has the mirrors 101 supported by torsion bars 102 and means 104 to vibrate the mirrors, and changes the amplitude of vibration of the mirrors.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light modulator having a mirror and a projection apparatus using the same, and more particularly to a projection type optical system for projecting an image on a large screen and a light modulator used therefor. .

[0002]

2. Description of the Related Art In recent years, it has become possible to electrically operate an actuator for driving a minute machine made by using a semiconductor process and a minute machine made by the same process. Is expected to be applied. Such micromachines are manufactured by MEMS (Micro Electro
Mechanical system), and has the features of high speed drive, small size and light weight. Taking advantage of such advantages, an optical modulator, an optical scanning means, etc. for modulating incident light using a micro mechanical component have been proposed.

As optical modulators, USP5497262, USP55921
A device called DMD disclosed in 88, etc., and USP5629
There is a device called GLV disclosed in 801 and USP5982553.

First, the DMD disclosed in USP54997262 and USP5592188 will be described with reference to FIG. FIG. 9 shows an outline of the structure of the micromirrors that make up the DMD. Actual DM
In D, the mirrors having the structure shown in FIG. 9 are arranged for the number of pixels of the image, and each pixel can be electrically driven individually. Reference numeral 14 in FIG. 9 is a mirror forming each pixel,
When the mirror 14 tilts, the light that illuminates the pixel is deflected. By this deflection, the light is binaryly deflected to modulate the light. FIG. 9B shows a configuration for tilting the mirror 14. FIG. 10 shows a projection device when a DMD is used. The array of micromirrors shown in FIG. 9 is 19 in the figure, and the image modulated by the DMD device 19 is projected onto the screen 21 via the optical system 20. At this time, the image on the screen 21 is modulated depending on whether the light passes through the pupil of the optical system 20 by the deflection of the mirror that constitutes the DMD device 19.

Further, the GLV disclosed in USP5629801, USP5982553 and the like will be described with reference to FIG. FIG. 11 shows one light modulation element constituting the GLV. FIG. 11A shows the configuration of one pixel, and the GLV modulates the light by diffracting the light by operating the plurality of ribbons 12 forming one pixel by static electricity. FIG. 12 shows the configuration of a projection device using GLV. The GLV is placed at 314 in the figure, and has a configuration in which the light modulated by 314 is projected on the screen via the optical system 336. With respect to the GLV optical modulator 314, the diaphragm of the projection optical system constitutes a Schlieren optical system, and is configured to modulate the light by controlling the amount of light transmitted through the diaphragm. .

On the other hand, as the optical scanning means, Japanese Patent Laid-Open No. 07-175
005 (Planar type galvanometer mirror and its manufacturing method:
Technologies such as Nippon Signal Co., Ltd. and Masayoshi Esashi) are disclosed. FIG. 13 shows a configuration example of JP-A-07-175005. To briefly explain the configuration, reference numeral 8 in FIG. 13 is a mirror, and this mirror 8 is mechanically connected to a substrate having a torsion bar 6 and can be rotated by twisting the torsion bar 6 to deflect light. It is a composition. A coil 7 is formed on the substrate to deflect the mirror 8. Also, the magnet 1 for applying a magnetic field to the coil 7
0 and 11 are set, and a Lorentz force is generated by applying a current to the coil 7, and the mirror 8 is driven by twisting the torsion bar.

FIG. 14 is a perspective view of FIG. 13, and the same numbers in FIGS. 13 and 14 indicate the same functions. The driving method will be described more clearly with reference to this figure.

The magnetic field generated by the magnets 10 and 11 shown in FIG.
If a current of i is applied to the coil 7, a force is generated in the direction of F in the figure. Due to this force, a torsion moment is generated with respect to the torsion bar 6, and the mirror 8 rotates. At this time, it is possible to vibrate the mirror by controlling the coil current, and it is also possible to obtain a large deflection angle by utilizing the mechanical resonance action.

[0009]

[Patent Document 1] Japanese Patent Application Laid-Open No. 07-175
Galvano mirrors such as 005 have not been used as light modulators. An object of the present invention is to propose a novel optical modulator using an element that deflects light by vibrating a mirror such as a galvanometer mirror.

[0010]

The optical modulator of the present invention is characterized by having a mirror and a means for vibrating the mirror, and changing the amplitude of vibration of the mirror.

Further, the optical modulator has a mirror and means for vibrating the mirror to resonate, and changes the amplitude of the resonance vibration of the mirror.
The tilt angle of the mirror can be increased.

Further, a plurality of the mirrors may be arranged in a predetermined direction and the vibration amplitudes of the plurality of mirrors may be individually changed.

Further, a light source for illuminating the light modulator,
A projection optical system for projecting an image of the light modulator on a screen, an image of the light source is formed near the diaphragm of the projection optical system via the light modulator, and a Schlieren optical system is formed by the projection optical system. By using the projection device characterized by being formed, it is possible to control the amount of light projected and display an image with a gradation.

Further, in the projection apparatus, the mirror of the light modulator has a one-dimensional array structure in which a large number of mirrors are arranged in the first direction, and has scanning means, and the scanning means has the light modulation. By reflecting the light from the container and scanning the screen with the reflected light, a two-dimensional image can be displayed.

Further, the scanning means may also have a function of a diaphragm of the projection optical system.

Further, in the projection device, the first direction and the scanning direction of the scanning means may be orthogonal to each other.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION First Embodiment A first embodiment according to the present invention is shown in FIG. FIG. 1 shows an outline of an optical modulator 110 according to the first embodiment of the present invention. The first embodiment is an optical modulator including a one-dimensional array. Reference numeral 101 denotes a mirror that constitutes each pixel, and is held by a support body 102. The support 102 is mechanically connected to the base 103. The support 102 functions as a torsion bar with respect to the mirror 101, and the mirror 101 is configured to be tilted about the support 102. A drive unit 104 is connected to each mirror 101, and the size of the tilt angle of the mirror 101 changes according to a drive signal input to the drive unit 104. Mirror 101,
The structures of the support 102 and the driving means 104 are the same as those shown in FIGS.

Each mirror 101 is constructed so as to be inclined with the support 102 as an axis. The driving means 104 is the mirror 101.
And a drive signal that causes the support 102 to mechanically resonate. Furthermore, the tilt angle of the mirror is changed by changing the magnitude of the signal.

An outline of the operation of the mirror 101 will be described with reference to FIG. Each mirror 101 is resonantly oscillated by driving means corresponding to each mirror 101 (not shown). FIG. 2 shows a state at a certain moment of the mirror 101 vibrating in resonance. In the figure, 101a is added to 101b with a signal that causes resonance oscillation with a larger amplitude. For this reason, the mirror 101a is tilted more largely, and the light 105a entering the mirror is deflected more than the light 105b entering the mirror 101b.

In FIG. 2, the inclination of the mirror 101 at a certain moment is shown, but the mirror 101 is resonantly oscillating, and the deflection angle of light is changed at high speed.

Next, a method of controlling the amount of light using the optical modulator of this embodiment will be described. FIG. 3 is a diagram for explaining the outline of the modulation method of the optical modulator according to the present invention. Ten
6 indicates an incident point of light from the light source, and incident light 108 indicates an incident point 10
6, the light modulator 110 of the present invention is illuminated with substantially parallel light through the optical system 107. In the optical modulator 110, as shown in FIG. 1, the mirror 101 is supported by the support 102. The driving means 104 is individually attached to the mirror 101 that constitutes each pixel of the light modulator 110. FIG. 3A shows a state in which the deflection angle of each mirror 101 is small or the mirrors are not tilted at a certain moment. In this state, the light reflected by the mirror 101 passes through the optical system 107 and returns to the vicinity of the incident point 106 as reflected light 109. Figure 3
(b) shows a case where the driving unit 104 increases the deflection angle of the mirror 101. Reference numeral 101d in FIG. 3B shows a case where the deflection angle of the mirror is large and the incident light 108 is largely deflected. Light with a large deflection angle
It passes through 107 and the optical path 109d different from the incident point 106. As shown in FIG. 3, when the deflection angle increases, the incident point 106
Will be greatly deviated from.

FIG. 4 shows a temporal characteristic of a certain mirror 101. The horizontal axis represents time, and the vertical axis represents the amplitude of the tilt angle of the mirror.

Since each mirror 101 is resonantly oscillating, it is operating at A (t) = Aosin (wt). A ₀ is the amplitude input by the driving means, w is the angular velocity at the time of resonance, and t is the time.

As shown in FIG. 3 (b), when the deflection angle of the mirror 101 becomes large, the reflected light path from the optical modulator 101 changes. Therefore, if a diaphragm 112 is provided in the vicinity of the incident point 106, the deflection angle will be different. Can change the light amount.

Specifically, when the amplitude of the mirror is larger than the threshold amplitude Ax, that is, in FIG. 4, the absolute value of the amplitude A (t) is larger than Ax ABS (A (t))> Ax When (ABS represents absolute value), the light is the aperture of the diaphragm.
When the amplitude is set to be deviated from 111 and the amplitude is changed by the driving means, the amplitude A (t) is changed as shown in FIG.
However, the time over the threshold amplitude Ax increases, and the light can be modulated.

The above is the light modulation method in this embodiment. With respect to the modulator 110, the diaphragm 112 is a diaphragm of a Schlieren optical system.

In this embodiment, since each mirror 101 is resonantly vibrated, a large deflection angle can be obtained.

For the driving means 104, static electricity, electromagnetic force or the like can be used.

In the present embodiment, the optical modulator 110 has a one-dimensional array structure, but the present invention is not limited to this and may be a two-dimensional array. The two-dimensional array can be formed by arranging the one-dimensional array in a direction substantially perpendicular to the direction in which the mirrors forming the one-dimensional array are arranged. When the two-dimensional array is used in the projection device, the scanning may be performed in the same manner as in the present embodiment, or when the mirrors are arranged in the same number as the number of pixels, the scanning means is not used. You can also Further, even in the case of a two-dimensional array, gradation can be produced by forming a schlieren system.

Further, as described in the present embodiment, the present optical modulator has a simple structure in which the mirror is supported by the supporting body functioning as a torsion bar and is driven by the driving means.

-Second Embodiment- A second embodiment according to the present invention will be described below. Figure 5
2A and 2B describe an optical modulator according to a second embodiment of the present invention and an optical projection device using the same.

FIG. 5A shows an outline of the scanning system 213 which is also a diaphragm. FIG. 5B shows an optical modulator 2 similar to that of the first embodiment.
10 is a schematic view of the configuration of 10, and a light modulator 210 is a one-dimensional light modulator having a pixel array including a mirror 201 in the plane of the drawing. The optical mirror is supported by a support 202 that functions as a torsion bar, and has a function of causing resonant vibration with respect to a direction perpendicular to the paper surface and deflecting light. Driving means 204 is arranged in each pixel, and this driving means resonates and vibrates the mirror 201 by a signal from a control means (not shown), and modulates light by changing the amplitude of its deflection angle by an input signal. To do.

FIG. 5 (c) is a diagram for explaining the outline of the optical system of the optical projection system of the second embodiment according to the present invention. In FIG. 5 (c), FIG. One-dimensional light modulator 210
FIG. 3 is a cross-sectional view from the viewpoint of the array direction being aligned in the direction perpendicular to the paper surface.

In FIG. 5B, a light source image 2 from a light source (not shown)
Incident light 208 from 06 to the light modulator 210 becomes substantially parallel light via the optical system 207 and illuminates the light modulator 210. The reflected light 209 from the optical modulator 210 passes through optical paths such as 209a and 209b according to the deflection angle of the mirror 201 of the optical modulator 210, and is emitted to the incident side via 207. As shown by 209a and 209b in the figure, the light source image is changed by the deflection angle of the mirror 201 of the optical modulator 210.
The optical path near 206 is very different. In the vicinity of the light source image 206, there is a scanning system 213, and when the deflection angle of the mirror 201 is a certain value or less like the optical path 209a, it is configured not to be scanned by the scanning system 213 and the reflection optical path 209b. When the deflection angle is large as described above, the scanning system 213 is configured to perform reflection scanning. FIG. 5A shows the configuration of the scanning system 213. The scanning system 213 includes a region 211 where reflection scanning is not performed.
And a region 212 for reflection scanning are formed by a mirror surface or the like.

As shown in FIG. 5 (c), the scanning system 213 is a plane mirror having a rotation axis 214 and rotatable about the direction perpendicular to the plane of the drawing. In the reflected light 209 of FIG. 5C, when the deflection angle in the optical modulator 210 is small, the scanning system 213
Since it is not reflected by, it exits the scanning system 213 like 217a. On the other hand, a light beam having a large deflection angle, such as 209b in FIG. 5B, is reflected by the scanning system 213, so the optical path is changed as 209d in the drawing. The light beam whose optical path has been changed is the optical system 21.
Reach on screen 218 via 6. Screen 218
And the optical modulator 210 have a conjugate relationship with the optical system 207, 21.
Since 6 is set, the image of the light modulator 210 is formed on the screen.

The scanning system 213 rotates about a rotary shaft 214,
Light 217d scans over screen 218. As a result, a two-dimensional image is formed on the screen 218.

In this embodiment, the reflection optical system 213 is arranged at the pupil position of the projection optical system 219 including the optical system 207 and the optical system 216 which make the screen 218 and the optical modulator 210 conjugate with each other. ), The reflective optical system 213 has a region 211 that does not reflect light and a region 212 that reflects light, and constitutes a Schlieren optical system for the optical modulator 210. In this case, the optical path of the reflecting optical system reaches the screen. The optical modulator 210 in this embodiment controls the amount of light per unit time by changing the amplitude of the tilt angle of the mirror, and displays an image with gradation, as in the case of the first embodiment.

FIG. 6 shows an illumination optical system 220 according to this embodiment.
Shows the configuration outline of. FIG. 6A illustrates the configuration of the illumination optical system in the direction corresponding to FIG. 5B, and FIG. 6B illustrates the configuration of the illumination optical system 220 corresponding to FIG. 5C.

In FIG. 6A, the luminous flux emitted from the light source 222 passes through the optical system 221 to form a light source image 206. The light source image 206 is in the vicinity of the diaphragm of the projection optical system shown in FIG.
A scanning system 213 is arranged. The light from the light source image 206 is the optical system.
The light modulator 210 is illuminated with substantially parallel light via 207.

On the other hand, as shown in FIG. 6B, the light from the light source 222 illuminates the optical modulator 210 via the optical system 221.
As shown in FIG. 5A, a region of the scanning system 213 that transmits light.
211 has a flat shape. The optical system 221 is configured by an anamorphic optical system so that the one-dimensional light modulator 210 can be linearly illuminated by transmitting through this region.

With the configuration as described above, it is possible to realize the projection device using the optical modulator according to the present invention.

-Third Embodiment- A third embodiment according to the present invention will be described below. In the second embodiment, the case where there is one light source has been described. Figure 7
In the configuration of the optical system corresponding to FIG. 5 (c), three light sources 222a, 2
It is a figure for demonstrating the illumination optical system at the time of using 22b and 222c together. The light sources 222a, 222b, 222c are connected to a control means (not shown) to control light emission. The emitted light has its optical path synthesized by the color synthesis system 224, and is configured to illuminate the light modulator 210. The projection optical system and the light modulation method are the same as those in the first and second embodiments, and the description thereof is omitted.

In this embodiment, since there is one light modulator 210, in order to display a color two-dimensional image on the screen 218, the light sources 222a, 222b, 222c are driven in a time-division sequential manner. A color image is displayed by an image.

The light sources 222a, 222b, 222c are, for example, red,
It is a light source having green and blue colors.

In the present embodiment, a method of displaying a color image by using three light sources and displaying images sequentially has been described.
The same effect can be obtained by disposing a wavelength selecting means such as a color filter between the optical modulator 210 and the optical modulator 210.

Fourth Embodiment The fourth embodiment according to the present invention will be described below. Although the case where three light sources are used has been described in the third embodiment,
In this embodiment, display of a color image when the white light source 222d is used will be described.

Also in this embodiment, the configurations of the illumination optical system, the projection optical system, and the light modulator are the same as those in the first and second embodiments, and the description thereof will be omitted. In FIG. 8, the optical system 207 and the optical modulator 210 are shown.
A color separation / synthesis system 225 is placed between the
Separate into 26a, 226b, and 226c. Three optical modulators 210a, 210b, 210c are arranged for each optical path. Light modulator
By driving 210a, b, c by a drive circuit (not shown) so as to correspond to the color of each optical path, a color image can be obtained on the screen.

In the above embodiment, the number of mirrors is small for simplicity, but the number is not limited to this.

Although each mirror is resonated and oscillated,
The present invention is not limited to this, as long as it is vibrating.

The method of driving the mirror is not particularly limited as long as it can control the amplitude of the vibrating mirror.

Further, in the above embodiments, the scanning system also has the function of the diaphragm, but the scanning system and the diaphragm may be separately provided.

[Brief description of drawings]

FIG. 1 is a configuration of an optical modulator according to a first embodiment.

FIG. 2 is an explanation of the operation of the optical modulator.

FIG. 3 is an explanation of an optical modulation method.

FIG. 4 is a description of an optical modulation method.

FIG. 5 is a schematic configuration diagram of the second embodiment.

FIG. 6 Description of illumination optical system

FIG. 7 is a schematic configuration diagram of the third embodiment.

FIG. 8 is a schematic configuration diagram of the fourth embodiment.

FIG. 9 is a conventional optical modulator.

FIG. 10: Projection device of conventional example

FIG. 11 is a conventional optical modulator.

FIG. 12: Projection device of conventional example

FIG. 13 is a conventional optical deflector.

FIG. 14 is a conventional optical deflector.

[Explanation of symbols]

101 mirror 102 support 103 base 104 driving means 105 rays 106 Light source image (condensed light) 107 Optical system 108 incident light 109 reflected light 110 Light modulation means 111 Aperture opening 112 aperture 113 Change in deflection angle over time 201 mirror 202 support 206 Light source image, light source focusing position 207 Optical system 208 incident light 209 reflected light 210 Light modulator 211 Non-reflection area (transmission area) 212 reflection area 213 Scanning system, diaphragm 214 rotation axis 217 Transmitted light, reflected light 218 screen 219 Projection optical system 220 Illumination optical system 221 optical system 222 light source 224 color composition system 225 color separation synthesis system

Claims (7)

[Claims] 1. An optical modulator comprising a mirror and means for vibrating the mirror, wherein the amplitude of vibration of the mirror is changed. 2. An optical modulator comprising a mirror and a means for causing the mirror to vibrate in resonance, wherein the amplitude of the resonance vibration of the mirror is changed. 3. The optical modulator according to claim 1, wherein a plurality of the mirrors are arranged in a predetermined direction, and the vibration amplitude of each of the plurality of mirrors is individually changed. 4. A light source for illuminating the light modulator according to claim 3, a projection optical system for projecting an image of the light modulator on a screen, and the light modulator in the vicinity of a diaphragm of the projection optical system. A projection device to form an image of the light source and a Schlieren optical system formed by the projection optical system. 5. The projection device according to claim 4, wherein the mirror of the light modulator has a one-dimensional array structure in which a large number of the mirrors are arranged in the first direction, and the scanning device has a scanning unit. Is a projection device that reflects light from the light modulator and scans the screen with the reflected light. 6. The projection device according to claim 5, wherein the mirror of the optical modulator has a one-dimensional array structure in which a large number of the mirrors are arranged in the first direction, and the scanning device has a scanning unit. Is a device for reflecting light from the light modulator, scanning the screen with the reflected light, and the scanning means being arranged in the vicinity of a diaphragm of the projection optical system. 7. The projection device according to claim 5, wherein the first direction and the scanning direction of the scanning unit are orthogonal to each other.