JPH086183A - Projector device - Google Patents

Abstract

PURPOSE: To improve picture quality on a screen, in enlargingly projecting a color image light beam through color synthesis with a dichroic mirror, by arranging the dichroic mirror for which a dichroic film is formed on the surface of a wedge-shaped glass material, for only the number corresponding to the plural color image light beams, and thereby preventing the color slurring of the dichroic mirror. CONSTITUTION: Plural light beams of a prescribed color are optically modulated by a light space modulator 2R, 2G, 2B, with the resultant plural color image light beams synthesized by a hue synthesizer 10R, 10G, 10B and projected through a projection lens 11. In this projector device 1, the hue synthesizer 10G, 10B is structured such that a dichroic mirror is arranged in the number corresponding to the plural color image light beams, a dichroic mirror with a dichroic film formed on the surface of a wedge-shaped glass material in which the incident plane and the light-emitting plane are nonparallel and in which a space narrows between the two planes in proximity to the incident light axis on the transmitting light side. As a result, the wedge shape prevents the color slurring, improving picture quality on the screen.

Description

Detailed Description of the Invention

[0001]

[Table of Contents] The present invention will be described in the following order. Field of Industrial Application Conventional Technology Problems to be Solved by the Invention (FIGS. 8 to 11) Means for Solving the Problems (FIGS. 1 and 6) Actions (FIGS. 1 and 6) Example (1) Projector Overall Configuration of Device (FIGS. 1 to 5) (2) Projector Device of Embodiment (FIGS. 6 and 7) (3) Other Embodiments Effect of the Invention

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projector device, and can be applied to, for example, a device for enlarging and projecting a color image by synthesizing three-color image light obtained through an optical spatial modulator.

[0003]

2. Description of the Related Art In recent years, due to advances in semiconductor manufacturing technology, projectors using a liquid crystal display panel as a spatial light modulator have become smaller and have higher performance. Liquid crystal projector devices are receiving attention. There are many types of liquid crystal display panels including transmissive type and reflective type, and there is also a projector device using an optical spatial modulator other than liquid crystal using semiconductor manufacturing technology.

As an optical spatial modulator other than the liquid crystal, a mirror-deflecting optical spatial modulator in which minute mirror surface elements are arranged on a two-dimensional plane according to the pixels constituting the screen and the reflection of each mirror surface element is utilized. (Hereinafter, this is called a mirror light valve)
(JP-A-60-179781, JP-A-3-40693, JP-A-3-174112). By using this mirror light valve as an image source to magnify and project a color image, the overall size of the device can be made similar to that of a liquid crystal projector device, and the efficiency of use of the light source can be improved compared to a liquid crystal display screen. A projector device capable of significantly increasing the brightness can be configured.

[0005]

In any projector device, the three-color light obtained by separating the light from the light source is modulated by the spatial light modulator, and the resulting three-color image light is combined. , Projects a color image consisting of a moving image or a still image. As a method of synthesizing the three-color image light, there are a method of arranging a projection lens for each color image light and synthesizing on the screen, and a method of synthesizing the light fluxes of the respective color image lights by hue and then projecting them on the screen through the projection lens. is there. Of these, the former usually requires three sets of projection lenses, and there is a problem that the configuration of the entire projector apparatus becomes large and the cost becomes high.

Further, as for the latter, as shown in FIG. 8 (A), a dichroic prism system having a dichroic interface DM inside a glass block GB or a method shown in FIG. As shown in, the plane mirror FM
There is a dichroic mirror system with dichroism. Of these, the dichroic prism type is
It is advantageous in terms of the distance from the optical spatial modulator to the projection lens, that is, the so-called back focus, but there are problems in terms of weight and price.

The dichroic mirror type has an advantage in weight and price, but when light beams containing different wavelengths are color-synthesized, there is a problem that the optical axis shifts due to the thickness of the mirror. In practice, there is no problem if the wavelength is a single wavelength, but normally, as shown in FIGS. 9 and 10, the shift amount changes depending on the wavelength. In the figure, the dichroic mirror 3 has a thickness of 1.5.
[Mm], the amount of deviation when the incident angle θ is 45 [°] using optical glass made of a parallel plate such as BK7 as the material is shown. Actually, the difference due to the wavelength within the same color becomes a problem rather than the shift amount itself. Naturally, the thinner the thickness, the smaller the amount of displacement, but the mirror is likely to be distorted, and the thickness cannot be made unlimitedly.

For example, as shown in FIG. 11, when the image h1 of the spatial light modulator is enlarged and projected on the screen through the projection lens L as an image h2 (= h1 xM) of M times (= L2 / L1). , The amount of deviation Δd caused by the dichroic mirror inserted between the spatial light modulator and the projection lens is also magnified M times on the screen, and the color deviation Δh2 (= M × Δd)
Becomes Therefore, since the amount of deviation Δd is about 2 to 3 μm, when the pixel size becomes 20 μm or less, the spread on the screen screen due to this becomes a problem, and the color bleeding within one color spot occurs. Occurs, and the display image deteriorates.

The present invention has been made in consideration of the above points, and when color image light is combined with a dichroic mirror for hue combination and enlarged and projected, a color shift due to the dichroic mirror is prevented to prevent an on-screen display. The present invention intends to propose a projector device capable of improving the image quality of.

[0010]

In order to solve such a problem, in the present invention, an optical spatial modulator (2R) in which lights of a plurality of predetermined colors are respectively modulated by a plurality of color image signals corresponding to the predetermined colors. , 2G, 2B), and a plurality of color image lights obtained as a result of the modulation are modulated by the hue combining units (10R, 10G,
In the projector device (1) that synthesizes the image with the projector lens (11) and projects through the projection lens (11),
G, 10B) is a dichroic film on the surface of a wedge-shaped glass material in which the entrance surface and the exit surface are non-parallel and the distance between the entrance surface and the exit surface close to the entrance optical axis on the transmitted light side is narrowed. The number of dichroic mirrors having the above-mentioned structure are arranged according to a plurality of color image lights.

[0011]

[Function] A hue combining section (10) for combining a plurality of color image lights
G and 10B), a dichroic film is formed on the surface of a wedge-shaped glass material in which the entrance surface and the exit surface are non-parallel and the distance between the entrance surface and the exit surface close to the incident light axis on the transmitted light side is narrowed. By disposing the number of dichroic mirrors formed according to the number of color image lights, color shift is prevented with a wedge plate shape, and when color image lights are combined with the dichroic mirrors and enlarged and projected, It can improve the image quality on the screen.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

(1) Overall Structure of Projector Device In FIG. 1, reference numeral 1 indicates three mirror light valves 2 corresponding to red, green and blue image data as a whole.
1 shows a projector device using R, 2G, 2B. 2 and 3 in which parts corresponding to those in FIG.
As shown in FIG. 3, the projection light L1 emitted from the high-intensity white light source 3 such as a metal halide lamp is U
Unnecessary ultraviolet rays are removed by a V filter (not shown), converted into parallel light through the condenser lens 4, bent by the first reflection mirror 5, and incident on the separation dichroic mirrors 6R, 6G, 6B. To do.

Separation dichroic mirrors 6R, 6G,
6B is a procession light L2 consisting of white light in red,
The green and blue lights LR, LG and LB are separated. This red,
The green and blue lights LR, LG, LB are obliquely bent upward by the second reflecting mirrors 8R, 8G, 8B through the beam shaping cylindrical lenses 7R, 7G, 7B, respectively, and reflected by the mirror light valves 2R, 2G, 2B. The surface is illuminated.

The mirror light valves 2R, 2G and 2B are
According to the pixel array of video data (for example, 768 x 576 pixels), a plurality of minute mirror surface elements each having a size of, for example, 17 [μm] square are arrayed, and thereby, a half
A reflective surface having a size similar to that of an inch CCD (solid-state image sensor) is formed. The micro mirror surface element is arranged corresponding to each memory cell of the frame memory according to the array of pixels of the video data, and the tilt state of the corresponding micro mirror surface element is changed individually according to the state of each memory cell. Has been done.

Practically, each micro mirror element is +10 [°] as shown in FIG. 4A when the memory cell is in the ON state, that is, effective as a pixel, with respect to the neutral state.
On the contrary, when the memory cell is in the OFF state, that is, when the memory cell is invalid as a pixel, for example, as shown in FIG.
It is designed to lean. As a result, the reflected light reflected by the mirror surface with respect to the incident light is switched so as to have an optical path difference of 20 [°] between the effective reflected light necessary for forming an image and the invalid reflected light that is ineffective.

In the case of the projector device 1, the image data for one frame of red, green, and blue is set in the frame memories corresponding to the respective mirror light valves 2R, 2G, and 2B, so that the effective reflected light is obtained. Red,
Green and blue image lights are formed. The red, green and blue image lights are respectively associated with relay lenses 9R, 9G and 9B.
Through dichroic mirrors for synthesis 10R, 10G,
It is guided to 10B and is combined as color image light, which is once imaged immediately before the projection lens 11 of the zoom lens structure, and then a screen (not shown) arranged outside the projection device 1 at a distance. Projected on top.

In the case of this projector device 1, the high-brightness white light source 3, the condenser lens 4, the first reflecting mirror 5, the separating dichroic mirrors 6R to 6B, and the cylindrical lenses 7R to 7B, and then the second reflecting mirror 8R. ~
The optical axis of the optical system of the projection lights L1 and L2 reaching 8B, the relay lenses 9R to 9B reflected by the mirror light valves 2R to 2B, and the dichroic mirror for synthesis 10R.
˜10B, the optical axis of the effective reflected light reaching the projection lens 11 is displaced by a predetermined height, thereby preventing interference between the projection light and the effective reflected light and the invalid reflected light. It is designed to get you.

Further, in the projector device 1, the beam shape of the projection light is shaped by the cylindrical lenses 7R to 7B, whereby the second reflecting mirror 8 is formed.
Even if the light is reflected obliquely upward by R to 8B, the reflecting surfaces of the mirror light valves 2R to 2B can be illuminated with a uniform illuminance.

Here, in this projector device 1, the optical device shown in FIG.
The circuit portion shown in FIG. 5 in which the same reference numerals are assigned to the corresponding portions is provided. In this projector device 1, as a video signal to be displayed, a video signal S1 input as an RGB signal from a video device or a V signal from a personal computer or the like is used.
The video signal S2 sent corresponding to GA (video graphics arrey) and the video signal S3 of VGA pattern can be selected.

These video signals S1, S2, S3 are
Each of them is input to the video select circuit 21 and selected, and the resulting video signal S4 is converted into a digital video signal S5 by the analog-digital conversion circuit 22,
It is input to the gamma correction circuit 23. The test pattern signal S6 generated by the test pattern generation circuit 24 is input to the gamma correction circuit 23 as needed. As a result, the gamma correction circuit 23 performs gamma correction on the digital video signal S5 or the test pattern signal S6 according to the set gamma correction parameter S7, and sends the resulting digital video signal S8 to the reformatting circuit 25.

The reformatting circuit 25 inputs the video signals S1 and RGB video signals S2 and S input as RGB signals.
The digital video signal S8 corresponding to 3 is, for example, mirror light valves 2R to 2B composed of 768 pixels × 576 lines.
The digital video signal S9 of red, green, and blue components obtained by performing re-formatting according to the arrangement of the mirror surface elements
R, S9B and S9G are sent to the corresponding frame memories 26R, 26G and 26B, respectively.

The frame memories 26R to 26B correspond to the mirror light valves 2R to 2B, respectively. The frame memories 26R to 2B are sequentially frame by frame in accordance with the control signal S10 input from the timing control circuit 27.
The contents of 6B are written in the mirror light valves 2R to 2B, whereby red, green and blue image lights are formed as effective reflected lights.

In the case of the projector device 1, the timing control circuit 27 uses the input video signals S1 to S3.
Using the system clock S12 generated by the clock generation circuit 28 in accordance with the phase control signal S11 based on the above, the frame memories 26R to 26B and the mirror light valve 2R are used.
The control signal S10 for controlling .about.2B is generated.

In the projector device 1, when a power switch (not shown) is turned on, the AC power S13 is supplied to the power supply circuit 30 and the lamp drive circuit 31. Of these, the power supply circuit 30 supplies a predetermined DC power S14 to each circuit section to start the operation of the projector device 1. Further, the lamp drive circuit 31 drives the high-intensity white light source 3 to be turned on, so that the white light source 3 emits the projection light L1.

According to the configuration of the projector device 1,
Mirror light valves 2R, 2G, and 2B corresponding to red, green, and blue are used as image sources, and the mirror light valves 2R to 2B are driven by red, green, and blue video signals, respectively, and white light is emitted. By irradiating red, green, and blue projection lights separated by color, and synthesizing the effective reflected light, and enlarging and projecting, compared with the conventional projector using a CRT. Projector device 1 with significantly smaller size, lighter weight and simple structure
Can be realized.

Further, since the mirror light valves 2R to 2B are designed to reflect the projection light,
As compared with the liquid crystal projector device, the utilization efficiency of light can be remarkably improved, and thus it is possible to realize the projector device which can be reduced in size and weight and which can increase the brightness of the displayed image.

(2) Projector device of embodiment Here, in the projector device 1 of this embodiment, of the dichroic mirrors for synthesis 10R, 10G, and 10B, the dichroic for synthesis that synthesizes the transmitted light and the reflected light on the emission side. The thickness of the mirrors 10B and 10G is as shown in FIG.
It is made of a glass material such as BK7 of 1.5 [mm], and is formed in a wedge plate shape in which the incident surface and the exit surface are inclined by 0.1 [°] from the parallel state. This inclination is selected in such a shape that the distance between the incident surface and the outgoing surface close to the incident optical axis of the transmitted light is narrowed.

The angle of this wedge plate (= 0.1 [°])
Is the relay lens 9R, 9
The focal positions of G and 9B are selected so that they are focused at positions 100 [mm] apart, for example. In practice, as shown in FIG. 7, a dichroic lens for synthesis having a shape such that the deviation of the optical axis is concentrated at the focal positions between the relay lenses 9R, 9G, 9B and the focal positions of these relay lenses 9R, 9G, 9B. By disposing the mirrors 10R, 10G, and 10B, color misregistration can be prevented in the virtual image formed at the focal position, and by enlarging and projecting this with the projection lens 11, the combining dichroic mirrors 10R and 10G. 1
The color shift due to 0B can be effectively prevented, and the image quality on the screen can be improved.

According to the above construction, as the dichroic mirrors 10G, 10B for synthesis, the incident surface and the outgoing surface are inclined by 0.1 [°] with respect to the parallel state, and the incident surface and the incident optical axis on the transmitted light side are close to each other. By forming a dichroic film on the surface of a wedge plate glass material where the distance between the emission surfaces becomes narrow, color shift is prevented with the wedge plate shape and it is combined with a dichroic mirror for composition and enlarged projection is performed. When
It is possible to realize a projector device capable of improving the image quality on the screen.

(3) Other Embodiments In the above-described embodiments, the mirror-deflecting optical modulator is used as a mirror-deflecting optical modulator depending on the arrangement of the pixels of the video data.
The case of using an array of 768 × 576 microscopic mirror elements has been described, but the array of microscopic mirror elements is not limited to this, and various selections such as those corresponding to NTSC or PAL television signals can be selected. Further, the arrangement is not limited to the two-dimensional arrangement, and the minute mirror surface elements may be arranged one-dimensionally and the projection light may be scanned to form an image.

Further, in the above-mentioned embodiment, the case where the present invention is applied to the projector device using the mirror-deflecting optical modulator as the image source is described, but the image source is not limited to the mirror-deflecting optical modulator. A projector device using a CRT or LCD may be used, and the point is that it is suitable for wide application to a device using a dichroic mirror for hue synthesis.

[0033]

As described above, according to the present invention, as a hue synthesizing unit for synthesizing a plurality of color image lights, the incident surface and the outgoing surface are non-parallel and the incident light is close to the incident light axis on the transmitted light side. The number of dichroic mirrors that have a dichroic film formed on the surface of a wedge-shaped glass material that reduces the distance between the output surface and the exit surface is achieved by arranging the number of dichroic mirrors according to the color image light. It is possible to realize a projector device capable of preventing the shift and improving the image quality on the screen when the color image lights are combined by the dichroic mirror and enlarged and projected.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing the overall configuration of a projector device using a mirror-polarized light modulator.

FIG. 2 is a schematic plan view for explaining an optical system of the projector device of FIG.

3 is a schematic rear view for explaining an optical system of the projector device of FIG. 1. FIG.

FIG. 4 is a schematic diagram for explaining the operation of the mirror surface element of the mirror surface deflection type optical modulator.

5 is a block diagram showing a circuit configuration of the projector device of FIG. 1. FIG.

FIG. 6 is a schematic diagram showing a dichroic mirror for synthesis in the projector device of the example.

FIG. 7 is a schematic diagram for explaining the arrangement of the dichroic mirror for synthesis.

FIG. 8 is a schematic diagram for explaining various hue combining methods.

FIG. 9 is a schematic diagram for explaining the deviation of the optical axis depending on the wavelength.

FIG. 10 is a characteristic curve diagram for explaining the shift of the optical axis depending on the wavelength.

FIG. 11 is a schematic diagram for explaining the influence of the deviation of the optical axis depending on the wavelength.

[Explanation of symbols]

1 ... Projector device, 2 ... Mirror light valve,
3 ... High brightness white light source, 4 ... Condenser lens, 5 ...
... 1st reflection mirror, 6 ... separation dichroic mirror, 7 ... beam shaping cylindrical lens, 8 ...
Second reflection mirror, 9 ... Relay lens, 10 ... Synthetic dichroic mirror, 11 ... Projection lens.

Claims (4)

[Claims] 1. A plurality of light beams of a predetermined color are optically modulated by an optical spatial modulator that is respectively modulated by a plurality of color image signals corresponding to the predetermined color, and a plurality of color image light beams resulting from the modulation are hues. In the projector device that synthesizes by a synthesizing unit and projects through a projection lens, the hue synthesizing unit is configured such that the incident surface and the outgoing surface are non-parallel and the distance between the incident surface and the outgoing surface is close to the incident optical axis on the transmitted light side. A projector device, wherein a number of dichroic mirrors, each having a dichroic film formed on a surface of a wedge-shaped glass material having a narrow interval, are arranged according to the plurality of color image lights. 2. When the plurality of color image lights obtained from the plurality of optical spatial modulators are imaged through a relay lens immediately before the projection lens, the dichroic mirror has an incident surface and an outgoing surface. The wedge-shaped glass material is selected in such a shape that the optical axis of the transmitted light of the dichroic mirror deviates depending on the wavelength is concentrated on the image forming position immediately before the projection lens. 1. The projector device according to 1. 3. The dichroic mirror has a thickness of
At 1.5 mm, the incident surface and the output surface should be
The projector device according to claim 2, wherein the projector device is formed of a wedge-shaped glass material inclined by 0.1 [°]. 4. The plurality of predetermined color lights are of three primary colors, and the color image lights of the three primary colors obtained by the spatial light modulator are combined by two dichroic mirrors. Item 1. The projector device according to item 1.