JP2004037702A - Projector apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projector apparatus with an optical system of simple configuration. <P>SOLUTION: The projector apparatus has a first liquid crystal plate 20 which modulates light with color signals by specified units of pixels constituting an image to be projected on a screen 26, a color filter 21 which is constituted by arranging RGB filters transmitting primary color light of R, G, and B respectively in specified pattern and converts light into the primary color light of R, G, and B through the RGB filters, and a second liquid crystal plate 23 which modulates the light with luminance signals by the pixels. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a projector device that projects an image on a screen.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, as a projector device that projects and displays an image on a screen, a three-plate type projector device that uses three liquid crystal display elements corresponding to three primary colors has been provided.
[0003]
The technology of the three-plate type projector device is described in detail in, for example, "Optical Technology Contact", September 1999, published by Japan Opto-Mechatronics Association.
[0004]
FIG. 9 is a cross-sectional view showing a schematic configuration of a conventional three-plate type projector device.
[0005]
The projector device 100 includes a light source 101, a fan 102 for cooling the light source 101, a first integrator 103, a second integrator 104, a polarization conversion element 105, a field lens 106, a first mirror 107, a first dichroic mirror 108, It has a second dichroic mirror 109, a first relay lens 110, a second mirror 111, a second relay lens 123, an AR 124, and a third mirror 125.
[0006]
The projector device 100 includes a fourth mirror 112, a first condenser lens 113, a first phase plate 114, a first trimming filter 115, a first liquid crystal plate 116, and a second phase plate 117. I have.
[0007]
The projector device 100 includes a second condenser lens 118, a third phase plate 119, a second trimming filter 120, a second liquid crystal plate 121, and a fourth phase plate 122.
[0008]
The projector device 100 includes a third condenser lens 126, a fifth phase plate 127, a third trimming filter 128, a third liquid crystal plate 129, and a sixth phase plate 130.
[0009]
The projector device 100 includes a cross dichroic prism 131 and a projection lens 132.
[0010]
Light emitted from the light source 101 is reflected by the first mirror 107 and enters the first dichroic mirror 108. In the white light that has entered the first dichroic mirror 108, green (G) light and blue (B) light are transmitted, and red (R) light is reflected. The G light and the B light transmitted through the first dichroic mirror 108 enter the second dichroic mirror 109, the B light is transmitted, and the G light is reflected.
[0011]
The R light reflected by the first dichroic mirror 108 is reflected by the fourth mirror 112, modulated by the first liquid crystal plate 116, and enters the cross dichroic prism 131.
[0012]
Similarly, the G light reflected by the second dichroic mirror 109 is modulated by the second liquid crystal plate 121 and enters the cross dichroic mirror 131. The B light transmitted through the second dichroic mirror 109 is reflected by the second mirror 111 and the third mirror 125, is modulated by the third liquid crystal plate 129, and enters the cross dichroic prism 131.
[0013]
The R light, the G light, and the B light incident on the cross dichroic prism 131 are both incident on the projection lens 132 and are projected on a screen (not shown).
[0014]
[Problems to be solved by the invention]
By the way, the above-mentioned three-plate type projector device performs processing for each of the three primary colors of RGB, and therefore requires a color separation system, a modulation system for each color, a synthesis prism system, and the like, and the optical system is complicated and large.
[0015]
The present invention has been proposed in view of the above situation, and has as its object to provide a projector device that projects an image on a screen and that has a simple configuration of an optical system.
[0016]
[Means for Solving the Problems]
In order to solve the above-described problem, a projector device according to the present invention projects an image on a screen, and a first liquid crystal that modulates light with a color signal for each predetermined unit of a pixel constituting the image. A color filter that arranges, in a predetermined pattern, RGB filters that respectively transmit RGB three primary colors corresponding to the first liquid crystal plate, and converts the light into RGB three primary colors by the RGB filters; A second liquid crystal plate that modulates light with a luminance signal for each pixel.
[0017]
The first and second liquid crystal plates can be disposed either before or after each other in the light traveling direction in the optical path from the light source to the screen. Further, the color filter can be arranged either before or after the first liquid crystal plate in the light traveling direction.
[0018]
Preferably, the projector device has a microlens array that condenses the RGB three primary color lights transmitted through the first liquid crystal plate and the color filters on cells corresponding to the predetermined unit in the second liquid crystal plate.
[0019]
Preferably, the projector device is a prism that separates light into three primary colors of RGB, and focuses the three primary colors of RGB separated by the prism on cells corresponding to the same color RGB filters in the first liquid crystal plate and the color filters. A micro lens array.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of a projector device according to the present invention will be described in detail with reference to the drawings.
[0021]
FIG. 1 is a cross-sectional view illustrating a schematic configuration of the projector device according to the first embodiment.
[0022]
The projector device 10 includes a light source 11, a fan 12 for cooling the light source 11, a first integrator 13, a second integrator 14, a polarization conversion element 15, a field lens 16, and a condenser lens 17. The members from the light source 11 to the condenser lens 17, except for the fan 12, constitute an illumination system for supplying a predetermined light beam to the projector device 10.
[0023]
The projector device 10 includes a first phase plate 18, a trimming filter 19, a first liquid crystal plate 20, a color filter 21, a second phase plate 22, a second liquid crystal plate 23, a third phase plate 24, It has a projection lens 25.
[0024]
The first liquid crystal plate 20 and the second liquid crystal plate 23 have a plurality of cells arranged in a plane, and modulate an image by controlling the optical rotation of transmitted light for each cell. In the present embodiment, the first and second liquid crystal plates 20 and 23 have the same cell arrangement.
[0025]
The first phase plate 18, the second phase plate 22, and the third phase plate 24 each act as a polarizing element that transmits linearly polarized light in a predetermined direction. The first liquid crystal plate 20 has first and second phase plates 18 and 22, and the second liquid crystal plate 23 has second and third phase plates 22 and 24. To control.
[0026]
The first liquid crystal plate 20 is controlled by a color signal, and modulates the light amount of any of the three primary colors of RGB converted by the color filter 21 for each cell.
[0027]
Each cell of the first liquid crystal plate 20 modulates light incident on a corresponding plurality of cells in the second liquid crystal plate 23. Each cell of the second liquid crystal plate 23 modulates a corresponding pixel constituting an image on the screen. Therefore, each cell of the first liquid crystal plate 20 modulates a corresponding plurality of pixels (predetermined units) on the screen. The plurality of cells correspond to RGB units (see FIG. 2 (B) i or FIG. 4 (A) u1) composed of a set of RGB filters in the color filter 21, and include a first cell as described later. in the embodiment correspond the three cells (see ₂₇ 1-27 ₃ in FIG. 3).
[0028]
In the second liquid crystal plate 23, the three primary colors of RGB emitted from the RGB units of the first liquid crystal plate 20 and the color filter 21 are mixed and incident on the corresponding three cells. The mixing of the three primary colors of RGB utilizes, for example, the spread of the luminous flux from the corresponding cell.
[0029]
The color filters 21 are arranged in the order of RGB in the horizontal direction on the basis of the screen on the screen corresponding to the position of each cell of the first liquid crystal plate 20, and the RGB filters are arranged so as to form vertical stripes (FIG. 4 (A)).
[0030]
The second liquid crystal plate 23 is controlled by a luminance (Y) signal, and modulates the amount of light transmitted through each cell. Into each cell of the second liquid crystal plate 23, RGB primary color lights emitted from the corresponding RGB units in the first liquid crystal plate 20 and the color filter 21 are mixed and input. Each cell of the second liquid crystal plate 23 corresponds to each pixel forming an image on the screen.
[0031]
FIG. 2 is a diagram illustrating generation of an image by the projector device 10 according to the first embodiment.
[0032]
FIG. 2A shows a main part of the projector device 10 including a first phase plate 18, a first liquid crystal plate 20, a color filter 21, a second phase plate 22, a second liquid crystal plate 23, Are shown, and a projection lens 25 is shown.
[0033]
In the following description, for convenience, it is assumed that the amount of light transmitted through the first liquid crystal plate 20 and the second liquid crystal plate 23 is modulated. The phase plates 18, 22, 24 before and after each of the liquid crystal plates 20, 23 are required to modulate the light amount only by rotating the polarization plane.
[0034]
FIG. 2B is a diagram illustrating a configuration of light in each unit in FIG.
[0035]
Predetermined convergent light of white light is incident on the first liquid crystal plate 20 from an illumination system. This white light is composed of the same amount of light of the three primary colors of RGB as shown in FIG.
[0036]
In the figure, “a” conceptually shows the arrangement of the RGB filters in the color filter 21 at the same time as the amounts of the RGB primary color lights. In the present embodiment, the color filter 21 is configured by arranging RGB filters in a vertical stripe shape, and a set of 3 × 1 RGB filters such as i, ii, and iii in the drawing corresponds to an RGB unit. . The same applies to the following.
[0037]
The first liquid crystal plate 20 modulates, for each cell, the amount of incident white light transmitted according to the input color signal. The light transmitted through the first liquid crystal plate 20 is transmitted through color filters 21 composed of RGB filters arranged at positions corresponding to each cell of the first liquid crystal plate 20, and is converted into three primary colors of RGB. As described above, in the first liquid crystal panel 20 and the color filter 21, color separation is performed by the input color signal.
[0038]
B in the drawing is a diagram showing the three primary colors of RGB transmitted through the color filter 21. FIG. The three primary color lights of RGB, which have the same light quantity in the white light in the figure a, are modulated in light quantity in RGB units.
[0039]
The control of the color signal in the first liquid crystal plate 20 is performed by the following equation (1) so that the maximum value of the light amount of the RGB primary color light of each RGB unit becomes constant in the RGB primary color light emitted from the color filter 21. ) For each RGB unit. For example, R, G, B and R, G, each of size Satoshi color signals of B, and K R, G, and the maximum value of the three primary light B, and the K constant. The magnitude of the signal of each color of the controlled three primary colors of RGB is represented by the following equation.
[0040]
R = R (K / K )
G = G (K / K ) (1)
B = B (K / K )
The three primary colors of RGB emitted from the color filters 21 are mixed for each RGB unit by using, for example, the spread of a light beam, and are incident on three cells corresponding to the RGB units on the second liquid crystal plate 23. In the figure, c is a diagram showing the mixed light incident on the cell of the second liquid crystal plate 23. Although the ratio of the three primary colors of RGB is different depending on the modulation in the first liquid crystal plate 20, the total amount of the three primary colors of RGB is almost equal as a result of the control according to the equation (1).
[0041]
The second liquid crystal plate 23 modulates the amount of light transmitted by the input luminance signal for each cell. Each cell of the second liquid crystal plate 23 corresponds to a pixel forming an image on the screen 26. The light modulated by the second liquid crystal plate 23 is projected on a screen 26 via a projection lens 25.
[0042]
In the figure, d is a diagram showing light modulated on the second liquid crystal plate 23. Light modulated in each of the three cells corresponding to the RGB unit contains the same amount of RGB primary color light, although the light amount is different. Note that each row in the figure d corresponds to a pixel on the screen 26.
[0043]
FIG. 3 is a diagram illustrating the arrangement of pixels on the screen 26.
[0044]
In this figure, for the sake of convenience, only some of the pixels are enlarged for the purpose of explaining the arrangement of pixels on the screen 26, and the ratio of the pixel size to the screen 26 is not accurate.
[0045]
Image displayed on the screen 26 is composed of a pixel such as pixel ₂₇ 1-27 _9. Pixels ₂₇ 1 to 27 _3, respectively correspond pixel ₂₇ 4-27 ₆ and the pixel ₂₇ 7-27 _9, for example, RGB unit i shown in FIG. 2 (B), ii, in iii. That is, the pixels ₂₇ 1 to 27 _9, the first liquid crystal panel 20 is modulated for the three primary colors of RGB light pixels of such 3 × 1 as a set. In each set of pixels, the proportions of the three primary colors of RGB are equal (see FIG. 2 (b) d). The pixel ₂₇ 1-27 _9, the second liquid crystal panel 23 is modulated luminance for each pixel.
[0046]
As described above, in the first embodiment, the modulation is performed in units of 3 × 1 pixels by the color signal, but the monochrome image by the luminance signal is modulated in units of each pixel. Accordingly, although the color resolution is reduced to one third of the luminance resolution, the human eye has a characteristic that the sensitivity to the color resolution is lower than that of the black and white image. The reduction in the level of the resolution for the image obtained by combining is not so noticeable.
[0047]
Further, the projector device of the first embodiment uses two liquid crystal plates 20 and 23 and three phase plates 18, 22 and 24. Compared with the conventional three-panel type projector apparatus using three liquid crystal plates and six phase plates, the number of liquid crystal plates and phase plates is much smaller. Further, a complicated spectroscopic optical system and a cross dichroic prism required in the three-plate type projector device are not required.
[0048]
As described above, in the first embodiment, the RGB filters are arranged in the horizontal direction and the color filters 21 arranged in the vertical stripes are used. However, in the color filters 21, the RGB filters may be arranged in another pattern. it can.
[0049]
FIG. 4 is a diagram showing various arrangements of the RGB filters in the color filter 21. In the figure, the arrangement of the RGB filters is shown based on the image displayed on the screen. That is, the horizontal direction and the vertical direction in the figure correspond to the directions in the image.
[0050]
FIG. 4A shows a first specific example of the arrangement of the RGB filters. The first specific example is adopted for the color filter 21 in the first embodiment, and RGB filters are arranged in the horizontal direction of the screen, and are sequentially arranged in a vertical stripe shape. The RGB unit u1 is composed of a set of 3 × 1 RGB filters. Therefore, the color resolution is 1/3 in the horizontal direction as compared with the luminance resolution.
[0051]
FIG. 4B shows a second specific example of the arrangement of the RGB filters. In the second specific example, RGB filters are arranged in the vertical direction of the screen and arranged in a horizontal stripe shape. The RGB unit u2 is composed of a set of 1 × 3 RGB filters. Therefore, the color resolution is １ ／ in the vertical direction as compared with the luminance resolution.
[0052]
FIG. 4C shows a third specific example of the arrangement of the RGB filters. In the third specific example, a set of 2 × 2 RGB filters including upper left R, lower left G, and upper right B is set as an RGB unit u3, and each side of the RGB unit u3 is shared with an adjacent RGB unit. As described above, they are arranged in the horizontal and vertical directions. Therefore, the color resolution is halved in both the horizontal and vertical directions as compared with the luminance resolution. In the third specific example, the RGB filters are arranged in a lattice, and the RGB unit u3 includes a filter that does not transmit light at the lower right. This is the same in the following fourth specific example.
[0053]
FIG. 4D shows a fourth specific example of the arrangement of the RGB filters. The fourth specific example has the same RGB unit u4 as the third specific example, but the RGB unit is shifted in the horizontal direction by one RGB filter for each row of the RGB unit u4 in the horizontal direction. Also in the fourth embodiment, the color resolution is halved in both the horizontal and vertical directions, as compared with the luminance resolution.
[0054]
By using the third or fourth specific example, in the first specific example and the second specific example, it is possible to improve the balance of resolution by extremely different color signals in the horizontal and vertical directions of an image. That is, the color resolution in the first specific example and the second specific example had a three-fold difference between the horizontal direction and the vertical direction. In contrast, in the third specific example and the fourth specific example, the horizontal and vertical color resolutions are equal.
[0055]
FIG. 5 is a diagram illustrating generation of an image according to the second embodiment.
[0056]
FIG. 5A is a cross-sectional view illustrating a configuration of a main part of a projector device according to the second embodiment. Members common to the projector device of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.
[0057]
The projector device according to the second embodiment is obtained by adding a microlens array 31 to the projector device according to the first embodiment. The configuration of other parts is the same as that of the projector device of the first embodiment shown in FIG.
[0058]
That is, the projector device according to the second embodiment has a microlens array 31 between the color filter 21 and the second phase plate 22 as compared with the first embodiment.
[0059]
The microarray lens array 31 is formed by integrating a plurality of lenses in a plane, and mixes the three primary colors of RGB emitted from the RGB units of the first liquid crystal plate 20 and the color filter 21 to form a second liquid crystal. The light is focused on the corresponding cells on the plate 23, respectively.
[0060]
FIG. 5B is a diagram illustrating a configuration of light in each unit in FIG. In the figure, a is white light incident from the illumination system, and is composed of the same amount of light of the three primary colors of RGB. In the drawing, “b” indicates RGB primary color light that is color-separated for each cell by the first liquid crystal plate 20 and the color filter 21. In the figure, “c” indicates light in which three primary colors of RGB, which are color-separated for each RGB unit, are mixed. In the drawing, d indicates light obtained by modulating the light mixed in the second liquid crystal plate 23 with the luminance for each cell corresponding to the RGB unit.
[0061]
In the projector device 10 of the second embodiment, the use of the microlens array 31 allows the light beams of the three primary colors of RGB to be accurately condensed on the second liquid crystal plate 23.
[0062]
FIG. 6 is a diagram illustrating generation of an image according to the third embodiment.
[0063]
FIG. 6A is a cross-sectional view illustrating a configuration of a main part of a projector device according to the third embodiment. Members common to the projector device of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.
[0064]
The projector device according to the third embodiment is obtained by adding a first microlens array 31, a second microlens 33, and a prism 32 to the projector device according to the first embodiment. Among them, the first microlens 31 is common to the microlens 31 in the second embodiment.
[0065]
That is, the projector device of the third embodiment is different from that of the first embodiment in that the distance between the prism 32, the first phase plate 18, and the first liquid crystal plate 20 before the first phase plate 18 is larger. , And a first microphone lens array 31 between the color filter 21 and the second phase plate 22.
[0066]
The three primary colors of light incident from the illumination system are directed in different directions by the prism 32. The three primary colors of RGB separated by the prism are condensed by the second microarray lens 33 into cells of the color filter 21 corresponding to the RGB filters of the same color. The three primary color lights transmitted through the color filters 21 are condensed by the first microarray lens 31 on the corresponding cells of the second liquid crystal plate 23.
[0067]
FIG. 6B is a diagram illustrating a configuration of light in each unit in FIG. 6A. In the figure, a indicates three primary colors directed in different directions by the prism.
[0068]
In the drawing, “b” indicates RGB primary color light that is color-separated for each cell by the first liquid crystal plate 20 and the color filter 21. Since the light incident on the liquid crystal plate 20 and the color filter 21 is previously separated into the three primary colors of RGB, there is no loss due to transmission through the color filter 21. For this reason, the light amount of the three primary colors of RGB transmitted through the color filter 21 is larger than that of the first or second embodiment.
[0069]
In the figure, c is light mixed with RGB primary color light, and d in the figure is light modulated on the second liquid crystal plate 23 by luminance for each cell.
[0070]
According to the third embodiment, the light incident on the first liquid crystal plate 20 and the color filter 21 is previously decomposed into three primary colors of RGB by the prism 32. Therefore, since there is no loss in the color filter 21, it is possible to secure three times the brightness as compared with the first embodiment.
[0071]
In the third embodiment, the three primary light beams of RGB are decomposed in the horizontal direction by the prism 32 and the second microlens array 33. However, depending on the configuration of the color filter, any of the horizontal and vertical directions can be used. Can be set to
[0072]
FIG. 7 is a diagram illustrating generation of an image according to the fourth embodiment.
[0073]
FIG. 7A is a cross-sectional view illustrating a configuration of a main part of a projector device according to the fourth embodiment. Members common to the projector device of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.
[0074]
The projector device according to the fourth embodiment is different from the projector device according to the first embodiment in that the color filter 21 is moved to a stage subsequent to the second liquid crystal plate 23, and the first liquid crystal plate 20 is controlled by a luminance signal. , The second liquid crystal plate 23 is controlled by a color signal. The configuration of other parts is the same as that of the projector device of the first embodiment shown in FIG.
[0075]
FIG. 7B is a diagram illustrating a configuration of light in each unit in FIG. In the figure, a is white light incident from the illumination system, and b is white light generated by a luminance signal for each cell of the first liquid crystal plate 20. In the figure, c is the RGB primary color light separated by the RGB units corresponding to the cells of the first liquid crystal plate 20 in the second liquid crystal plate 23 and the color filter 21. In the figure, “d” is obtained by combining three primary colors of RGB separated on a RGB unit on the screen 26.
[0076]
In the fourth embodiment, the cells on the first liquid crystal plate 20 correspond to the pixels on the screen 26. In addition, the cells of the first liquid crystal plate 20 correspond to the cells of the RGB unit in the second liquid crystal plate 23 and the color filters 21, and the pixels on the screen 26 correspond to the cells.
[0077]
FIG. 8 is a sectional view showing the configuration of the fifth embodiment of the projector device.
[0078]
The projector device according to the fifth embodiment is obtained by replacing the second liquid crystal plate 23 and the third phase plate 24 of the projector device according to the first embodiment with DLP elements 34. The DLP element has a number of fine mirror surfaces, and modulates an image projected on a screen by controlling the angle of each mirror surface.
[0079]
The DLP element 34 is arranged so as to be inclined with respect to the optical axis from the illumination system to the second liquid crystal plate 22. The light modulated by the DLP element 34 travels in a direction in which the light is reflected by the DLP element 34, and is projected on a screen 26 via a projection lens 25. The configuration of other parts is the same as that of the projector device of the first embodiment shown in FIG.
[0080]
According to the above-described embodiment, members such as a phase plate, a liquid crystal plate, a spectral optical system, and a dichroic mirror can be remarkably reduced as compared with a conventional three-plate type projector device. Despite this, the resolution of the black and white image is equivalent to the three-plate type. Although the color resolution is lower than that of the three-panel type, the human eye has a very low resolution for color as compared with the black and white resolution, so that the reduction of the resolution is at a level that causes little problem.
[0081]
In the above-described embodiment, the microlens array is shown as an independent member. Alternatively, a microarray lens added to the liquid crystal plate to increase the aperture ratio may be used. Further, the light collection of the three primary colors of RGB by the microlens array can be arbitrarily set in either the horizontal direction or the vertical direction of the image depending on the configuration of the color filter. The light of the three primary colors of RGB may be condensed by the microlens array on a stripe or in a grid depending on the configuration of the color filter.
[0082]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a projector device that projects an image on a screen and has an optical system with a simple configuration.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating a schematic configuration of a projector device according to a first embodiment.
FIG. 2 is a diagram illustrating generation of an image according to the first embodiment.
FIG. 3 is a diagram illustrating an arrangement of pixels on a screen.
FIG. 4 is a diagram illustrating generation of an image according to a second embodiment.
FIG. 5 is a diagram illustrating generation of an image according to a third embodiment.
FIG. 6 is a diagram illustrating a specific example of an RGB array in a color filter.
FIG. 7 is a diagram illustrating generation of an image according to a fourth embodiment.
FIG. 8 is a diagram illustrating generation of a screen according to a fifth embodiment.
FIG. 9 is a block diagram showing a schematic configuration of a conventional three-plate type projector device.
[Explanation of symbols]
Reference Signs List 10 Projector device 11 Light source 17 Condenser lens 18 First phase plate 20 First liquid crystal plate 21 Color filter 22 Second phase plate 23 Second liquid crystal plate 24 Third phase plate 25 Projection lens 26 Screen

Claims (3)

In a projector device that projects an image on a screen,
A first liquid crystal plate that modulates light with a color signal for each predetermined unit of a pixel that forms an image;
Corresponding to the first liquid crystal plate, an RGB filter that transmits RGB three primary color lights is arranged in a predetermined pattern, and a color filter that converts the light into RGB three primary color lights by the RGB filter;
A second liquid crystal plate that modulates light with a luminance signal for each pixel;
Projector device having 2. The projector device according to claim 1, further comprising a microlens array that focuses the three primary colors of RGB transmitted through the first liquid crystal plate and the color filters on cells corresponding to the predetermined unit in the second liquid crystal plate. 3. A prism that separates light into three primary colors of RGB;
A microlens array for condensing the three primary colors of RGB separated by the prism on cells corresponding to the same color RGB filters in the first liquid crystal plate and the color filters;
The projector device according to claim 1, further comprising:

Images