JP2002323674A - Projection video device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a projection video device which does not require provision of motors for both of a 3 color rotary filter and a polygon mirror and is constituted of one single motor, and in which system design is easy, equipment is made small-sized and light-weighted, noise and vibration can be decreased, and cost can be reduced with a simple structure. SOLUTION: The projection video device is provided with a light source 2, an optical modulation means 5 which has a piezoelectric body provided with a reflective surface 17 for reflecting the light, reflects the light from the light source 2 by the reflective surface 17 with the inverse piezoelectric effect of this piezoelectric body, and modulate the light, and a rotating polygon mirror 10 which has a plurality of reflective surfaces 11 in the circumferential surface, reflects the lights respectively made incident on the reflective surfaces 11 from the optical modulation means 5 by rotating reflective surfaces 11, and scans the lights on the predetermined surface. In the projection video device 1, the reflective surfaces 11 of the rotating polygon mirror 10 selectively reflect only one color among three primary colors of lights, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention selectively includes an RGB color filter having a light modulation means and a rotating polygon mirror, and having a plurality of reflecting surfaces of the rotating polygon mirror having predetermined transmission spectra corresponding to three primary colors of light. By eliminating the need for synchronous control of the three-color rotating filter, its driving motor, drive circuit, and rotating polygon mirror, the device has a simple structure, can be made smaller and lighter, and is easier to manufacture and more productive. The present invention relates to a projection video apparatus which can be improved and cost can be reduced.

[0002]

2. Description of the Related Art In a projection image apparatus, light from a light source is incident on a deflecting / reflecting surface of a rotating polygon mirror (polygon mirror) via a three-color rotating filter and light modulating means. And a method in which the deflected light is projected onto a predetermined surface by a projection lens.

FIG. 8 is a schematic configuration diagram showing a projection video apparatus for performing color synthesis using such a three-color rotation filter. The light from the light source 32 of the projection video device 31
3, the light is modulated by the light modulation element 35, passes through the slits 38 of the thin plate member 37, is reflected by the reflection surface of the polygon mirror 39, and then passes through the fθ lens 40 and the projection lens 41. Is scanned on the screen 42.

[0004]

However, in the projection image apparatus 31 as described above, it is necessary to precisely rotate the three-color rotation filter 33 and the polygon mirror 39 with respect to the light from the light source. It is difficult to perform such synchronization control precisely, and there is a possibility that a good image cannot be formed due to a synchronization deviation or the like.

Further, in the projection image apparatus 31 as described above, the three-color rotation filter 33 and the polygon mirror 39 are provided with motors as rotation means, respectively.
It is necessary to rotate two motors synchronously. As a result, equipment costs increase, system design becomes complicated, and space for two motors is required. There was a problem of doing.

Accordingly, the present invention does not require the motor to be provided in both the three-color rotating filter and the polygon mirror, and is configured so that only a single motor is required. Therefore, the device can be reduced in size and weight with a simple structure. It is another object of the present invention to provide a projection video apparatus capable of reducing noise and vibration and reducing cost.

[0007]

A projection image apparatus according to the present invention has a light source and a piezoelectric body provided with a reflection surface for reflecting light, and the reflection surface is formed by the inverse piezoelectric effect of the piezoelectric body. A light modulation unit that reflects and modulates light from the light source, and has a plurality of reflection surfaces on a peripheral surface, and by rotating the plurality of reflection surfaces, each of the plurality of reflection surfaces is converted from the light modulation unit to the plurality of reflection surfaces. A rotating polygon mirror for reflecting incident light and scanning on a predetermined surface, wherein a plurality of reflecting surfaces of the rotating polygon mirror selectively reflect only one of three primary colors of light. It is assumed that.

In the projection image apparatus according to the present invention, instead of the three-color rotating filter, the plurality of reflecting surfaces of the rotary polygon mirror selectively reflect only one of the three primary colors of light. Therefore, there is no need to perform synchronous control with the three-color rotating filter, its driving motor, drive circuit, and polygon mirror. This makes it possible to reduce the size and weight of the device with a simple structure, facilitate manufacture, improve productivity, and reduce costs. Furthermore, since a three-color rotation filter and a driving motor are not required, noise and vibration such as motor noise and wind noise can be reduced.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a projection video apparatus according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view showing a schematic configuration of a projection video apparatus according to the present invention. White lamp light source 2 of projection video device 1
Light is converged in parallel by the collimation lens 3 and is a light modulation element (PLV: Piezoele
ctric Light Valve) 5. A mirror surface 17 described later, which is a reflection surface of the light modulation element 5, is controlled and driven by the controller 7, and is set so that the reflection direction can be changed by, for example, an applied voltage of about 0.5 degrees at maximum. When no voltage is applied, the reflected light from the mirror surface 17 is totally reflected by the mirror 8 and absorbed by the light absorber 9. When the voltage is applied to a maximum, the reflected light from the mirror surface 17 is barely reflected by the mirror 8, and is projected onto the polygon mirror 10, which is a rotating polygon mirror. The light reflected by the polygon mirror 10 is scanned on a screen 15 via an fθ lens 13 and a projection lens 14. The light modulation element 5 and the polygon mirror 10 will be described later in detail.

The present invention relates to a projection video apparatus using a light modulating element 5 and a polygon mirror 10, wherein the polygon mirror 1
By selectively attaching an RGB color filter 12 having a predetermined transmission spectrum corresponding to the three primary colors of light to the reflection surface 11 of the 0, the three-color rotation filter, its driving motor, drive circuit, and a polygon mirror. Synchronous control is not required, the structure is simple, the size and weight of the device can be reduced, manufacturing is easy, productivity is improved, and cost can be reduced.

First, the light modulation element 5 will be described. The light modulating element 5 moves the mirror surface 17 with an analog amount, turns on / off or adjusts the amount of single-wavelength light (including infrared rays and ultraviolet rays) and visible light, and is mainly used for a projection or projection image device such as a projector. used. The base of the light modulation element 5 utilizes the inverse piezoelectric effect of converting electric energy into mechanical energy, and arranges the mirror surface 17 for reflecting light in a single in-line, and controls the reflection direction in an analog manner by expansion and contraction by the inverse piezoelectric effect. .

FIGS. 2A and 2B are schematic views showing the basic structure of the light modulation element, wherein FIG. 2A is a plan view, and FIG. 2B is a sectional view taken along line XX of FIG. As shown in FIG. 2B, for example, the light modulation element 5 includes a laminated piezoelectric body 16A on a ceramic substrate (not shown).
Is formed in a laminated structure in which an aluminum (or gold) film is provided as a mirror surface 17 on the upper surface of the piezoelectric element 16. One or more stages are possible.
As described above, by using an inexpensive ceramic material for the substrate, the substrate is inexpensive, has good shock resistance, vibration resistance, heat resistance, and high reliability.

As shown in FIG. 2A, this planar structure is formed by cutting a single in-line laminated piezoelectric body 16A provided with electrodes at regular intervals.
By dividing into _{1 to} 16 _n , for example, the length L: 35
Pixel groups 16 _{1 to} 16 _{n of} 0 μm and width W: 150 μm
Are formed in a total of 1024 rows with a gap l = 50 μm, and are provided with 750 lines, all of which are formed in the same structure using the same material.

These pixel groups 16 _{1 to} 16 _1
As described later, _n reflects the reflected light with an optical path difference due to the inclination of the mirror surface 17, and controls the reflected light in an analog manner to project it on the screen.

Accordingly, the mirror surface 17 when no voltage is applied changes relatively due to its structure, even if there is a temperature change or a change with time, so that the influence is canceled and the relative position is kept constant and the quality deteriorates. Absent. Further, even when a voltage is applied, the relative position is stable and a good reflection angle can be obtained.

The second feature is that, as shown in FIG.
Since the number of pixels can be reduced and the structure can be simplified as compared with a surface device such as a D (Digital Mirror Device) or a liquid crystal, the manufacturing is easy and the yield is improved.

A third feature is that the voltage applied to the movable portion can be used in an analog amount or a digital amount. Normally, in the movable method by electrostatic attraction, even if driven by an analog amount, there is a variation and cannot be used.However, the piezoelectric element is a solid-state element, and the movable amount and the applied voltage are almost proportional to each other. Accordingly, a piezoelectric element having a lower speed can be used, and the cost can be reduced.

Further, in the case of mounting, due to dust and external force, PL
In order to protect V, sealing measures such as covering the surface with glass or the like are naturally necessary. In addition to the above-mentioned reasons, a ceramic substrate having excellent thermal conductivity for heat radiation should be selected.

Although the mirror angle of the mirror surface 17 can be made constant by applying a bias voltage to each pixel group 16 even if the mirror angle varies during manufacturing, it is usually necessary to apply a bias voltage to the element because of a small hysteresis. Absent.
Then, analog and digital signals can be used for input and output signals. Since the PLV is a mirror reflection, it can be used for laser light and visible light, and is a highly developable device that matches at the time of the prosperity of laser light as well as now and in the future.

As shown in FIG. 3, the light modulating element 5 has a piezoelectric body in which an active portion 20 made of, for example, lead titanate / zirconate (PbTiO ₃ .PbZrO ₃ ) is built in a main body 19 made of, for example, ordinary ceramic. Driver (piezoelectric) 18
May be formed on the substrate 21. In this case, the positional relationship of the active part 20 in the main body 19 is such that the distances l ₁ and l ₂ from the main body outside in the L direction are equal, the distance w _{1 from} the main body outside in the width W direction is large, and w ₂ is small. by the difference in stress occurs between the w ₁ and w ₂ when the voltage applied to the piezoelectric body 18, as shown, the piezoelectric body 18 is bent as indicated by a broken line, the upper surface 23 is bent before And after bending
Displace by an angle, for example, 0.5 degrees. On this upper surface 23, the mirror surface 1
7 is formed.

FIG. 4 is a view for explaining a change in the mirror angle of the mirror surface 17 due to the bending of the piezoelectric body 18 due to the application of a voltage to the piezoelectric body 18. As shown in FIG. 4A, when no voltage is applied to the piezoelectric body 18, the mirror angle of the mirror surface 17 is 0 degrees, and the mirror 8 is totally reflected. Further, as shown in FIG. 4B, when the maximum voltage is applied to the piezoelectric body 18, the mirror surface 1
Mirror angle theta ₁ of 7 becomes, for example, 0.5 degrees, the incident light to the mirror 17 is emitted at a large angle, barely a state which is not reflected by the mirror 8, all the reflected light polygon mirror 1
Projected to 0. Further, as shown in FIG. 4 (c), when applied about 1/2 voltage than the maximum piezoelectric body 18, the mirror angle theta ₂ of the mirror 17 is, for example, 0.3 degrees, the incident light to the mirror surface 17 Are emitted at a relatively small angle, a part is reflected by the mirror 8, and the remaining part is projected to the polygon mirror 10. As described above, by adjusting the mirror angle (inclination angle) of the mirror surface 17, the reflected light can be reflected with an optical path difference, and the reflected light can be controlled in an analog manner and projected on the screen.

Next, the polygon mirror 10 will be described. FIG. 5 is a perspective view of the polygon mirror 10. The polygon mirror 10 has six reflecting surfaces 11R, 11G,
11B, 11R, 11G, and 11B (hereinafter, collectively referred to as reflection surfaces 11) are members of a regular hexagonal prism, and are rotated at a constant angular velocity in the direction of arrow A about the axis 10a, so that each reflection surface 11 The horizontal scanning is performed by reflecting the received light within a certain angle range. The axis 10 a of the polygon mirror 10 has a DC micromotor 25
Are directly connected, and are rotationally driven by the DC micromotor 25.

The reflecting surface 11 is configured such that a pair of parallel surfaces reflect only red, green, and blue, respectively.
That is, as each reflecting surface 11, a reflecting surface 11R that reflects only red, a reflecting surface 11G that reflects only green, and a reflecting surface 11B that reflects only blue are sequentially provided on the side surface of the polygon mirror 10. .

FIG. 6 is a side sectional view of the reflection surface 11 of the polygon mirror 10. As shown in FIG. A mirror surface 10b made of an aluminum film or the like is provided on the surface of the polygon mirror 10. For example, red, green, and blue pigment-based paints are applied, printed, or coated on the mirror surface 10b, and red and green with high transmittance are provided. , Blue color filters 12R, 12G, 12
B is formed. Reflecting surfaces 11R, 11G, and 11B are formed by the mirror surfaces 10b and the red, green, and blue color filters 12R, 12G, and 12B, respectively.

That is, the light incident on the red reflecting surface 11R of the polygon mirror 10
The light passes through 2R, is reflected by the mirror surface 10b, passes through the red color filter 12R again, and is emitted toward the fθ lens 13. Accordingly, since the light incident on the reflection surface 11 of the polygon mirror 10 passes through the color filter 12 twice, a color filter having a high transmittance is desirable.

A light beam deflected at a constant angular velocity by a polygon mirror 10 having a plurality of reflecting surfaces 11 on its peripheral surface is imaged on a screen 15 and a large-diameter fθ is used to enable constant-speed scanning. A lens 13 is used.

For example, spots formed on the screen 15 by the optical system must be correctly scanned at equal intervals. That is, since the polygon mirror 10 rotates at a constant angular velocity, the spot on the screen 15 needs to move in proportion to the rotation angle.

FIG. 7 is a view for explaining the relationship between the image height and the incident angle of the fθ lens as a scanning lens. Assuming that the focal length of the fθ lens is f, the relationship between the image height y on the scanning plane and the angle θ deflected from the optical axis by the polygon mirror 10 is y = f · θ, which is called fθ characteristic showing uniform velocity. The equation holds. In a camera lens, the increase in y increases as θ increases. Therefore, if such a camera lens is used as a scanning lens, the shape of the camera lens becomes wider as it goes to the periphery. In this case, the spot on the screen 15 can be moved exactly in proportion to the rotation angle of the polygon mirror 10, and the scanning can be performed at regular intervals.

Next, the operation of the projection video apparatus 1 according to the present embodiment will be described. As shown in FIG. 1, light from the white lamp light source 2 is converged in parallel by the collimation lens 3 and is introduced into the light modulation element 5. The light modulation element 5 is controlled and driven by the controller 7, and the light modulation element 5
Is set so that the reflection direction can be changed by an applied voltage of about 0.5 degree at the maximum, and when no voltage is applied, the reflected light of the mirror surface 17 of the light modulation element 5 is totally reflected by the mirror 8, The light is absorbed by the light absorber 9. When the voltage is applied to the maximum, the mirror angle of the mirror surface 17 of the light modulation element 5 is changed by about 0.5 degrees, and the light reflected by the mirror surface 17 is not reflected by the mirror 8 but is projected on the polygon mirror 10.

Since the polygon mirror 10 rotates in the direction of arrow A, the rotation of the polygon mirror 10 causes, for example, the color light rays that have been reflected on the reflecting surface 11R and reached the screen 15 to be horizontally inserted into the red monochromatic light. Is displayed for one frame. Next, as the rotation of the polygon mirror 10 proceeds, the next reflection surface 11G appears, and the color light rays reflected by the reflection surface 11G and reaching the screen 15 are horizontally subtracted, so that an image of green monochromatic light is converted to one. Frames are projected. Then, when the rotation of the polygon mirror 10 further proceeds, the next reflection surface 11B appears, and the color light rays reflected on the reflection surface 11B and reaching the screen 15 are horizontally subtracted, and an image of blue monochromatic light is formed. One frame is displayed. By rotating the polygon mirror 10 by three surfaces in this manner, a color image by additive color mixture can be recognized.

The rotation of the polygon mirror 10 is, for example, 72
0 min ^-1 (rotation / minute), that is, 72 frames / minute
Seconds, 24 frames / second. Each color (red, green, blue). It is desirable that the insertion on the screen 15 be 60 Hz or more. When a light beam is reflected by the polygon mirror 10, the light passes through the color filter 12 having a high transmittance twice and at the time of reflection and is colored. This colored light beam is applied to the fθ lens 1
3 enables scanning at a constant speed, and the projection lens 14
And reaches the screen 15. It should be noted that there is no practical problem if the polygon mirror 10 is rotated so that flicker cannot be seen.

Therefore, the reflection surface 11 of the polygon mirror 10
Has a predetermined transmission spectrum corresponding to the three primary colors of light.
Since the GB color filter 12 was selectively attached,
The three-color rotating filter can be omitted, and the synchronous control with the driving motor, the drive circuit, and the polygon mirror of the three-color rotating filter is not required. The simple structure, the system design is easy, and the size and weight of the device can be reduced. In addition, manufacturing is easy, productivity is improved, and cost can be reduced. Furthermore, since a three-color rotation filter and a driving motor are not required, noise and vibration such as motor noise and wind noise can be reduced.

In the above-described embodiment, the polygon mirror 10 is hexagonal. However, the present invention is not limited to this, and it is a matter of course that other even or odd reflecting surfaces 11 may be provided. On the mirror surface 10b of the polygon mirror 10, for example, red, green, and blue pigment-based paints are applied, printed, or coated to form red, green, and blue color filters 12R, 12G, and 12B with high transmittance. But
The present invention is not limited to this, and the color filters 12R, 12G, and 12B having high transmittance may be formed by other methods.

[0034]

As described above, according to the present invention,
Instead of the three-color rotating filter, the plurality of reflecting surfaces of the rotating polygon mirror are configured to selectively reflect only one of the three primary colors of light. And synchronization control with a drive circuit and a rotating polygon mirror is not required. As a result, the system can be designed with a simple structure, the system can be easily designed, the size and weight of the device can be reduced, the manufacturing is easy, the productivity is improved, and the cost can be reduced.

Since it is not necessary to rotate the three-color rotation filter and the rotary polygon mirror synchronously with high precision as in the prior art,
An image can be satisfactorily formed on a predetermined surface without occurrence of synchronization shift or the like. Furthermore, since a three-color rotation filter and a driving motor are not required, noise and vibration such as motor noise and wind noise can be significantly reduced.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a projection video apparatus according to the present invention.

FIG. 2 shows a schematic diagram of a basic configuration of a light modulation element,
(A) is a plan view, and (b) is a cross-sectional view taken along line XX of (a).

FIG. 3 is a schematic side view of a light modulation element.

FIG. 4 is a diagram illustrating a change in a mirror angle of a mirror surface due to application of a voltage to a piezoelectric body.

FIG. 5 is a perspective view showing a polygon mirror.

FIG. 6 is a side sectional view of a reflection surface portion of a polygon mirror.

FIG. 7 is a diagram illustrating the relationship between the image height of the fθ lens and the angle of incidence.

FIG. 8 is a schematic configuration diagram illustrating an example of a projection video device that performs color synthesis using a three-color rotation filter.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Projection imaging device, 2 ... White lamp light source (light source), 3 ... Collimation lens, 5 ... Light modulation element (light modulation means), 7 ... Controller, 8 ...
Mirror, 9: light absorber, 10: polygon mirror (rotating polygon mirror), 10a: axis, 11R, 11G, 1
1B: reflective surface, 12R, 12G, 12B: color filter, 13: fθ lens, 14: projection lens, 15: screen (predetermined surface), 16A:
Laminated piezoelectric body, 16 _{1 to} 16 _n ... Pixel group, 17
... mirror surface (reflection surface), 18 ... piezoelectric driver (piezoelectric)

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) H04N 5/74 H04N 5/74 B

Claims (5)

[Claims] 1. A light modulator, comprising: a light source; and a piezoelectric body provided with a reflection surface for reflecting light, wherein the light from the light source is reflected and modulated on the reflection surface by an inverse piezoelectric effect of the piezoelectric body. Means for rotating a plurality of reflecting surfaces on a peripheral surface, and rotating the plurality of reflecting surfaces to reflect light respectively incident on the plurality of reflecting surfaces from the light modulation means and scan on a predetermined surface. A projection video apparatus, comprising: a polygon mirror, wherein the plurality of reflection surfaces of the rotary polygon mirror selectively reflect only one of three primary colors of light. 2. An RGB color filter having a predetermined transmission spectrum corresponding to each of three primary colors of light is selectively attached to a plurality of reflection surfaces of the rotary polygon mirror. 3. The projection imaging apparatus according to claim 1. 3. The projection video apparatus according to claim 1, wherein the reflection of the incident light of the light modulation unit is controlled in an analog manner by an applied voltage. 4. The method according to claim 1, wherein an amount of expansion and contraction of the piezoelectric body and a reflection angle of the incident light are proportional to each other, and a light amount is quantitatively controlled by controlling a voltage applied to the piezoelectric body. Projection imaging device. 5. The projection video apparatus according to claim 1, wherein the piezoelectric bodies are provided in common or divided in an inline direction.