JPH08234184A - Color liquid crystal projection display device - Google Patents

Abstract

PURPOSE: To project a bright color picture excellent in light utilization efficiency by reducing the loss of light quantity CONSTITUTION: A liquid crystal display element 5 is constituted so that R, G and B picture elements are two-dimensionally arranged in an array state, and color display is performed by a set of R, G and B picture elements 5a, 5b and 5c in a column direction. A beam compressor 3 is provided with a convex lens 3a and a concave lens 3b where cylindrical lenses are plurally formed in the array state. The size of the cylindrical lens of the convex lens 3a is equal to those of three picture elements(a set of R, G and B picture elements) in the column direction of the liquid crystal display element and the three picture elements of the incident luminous flux 11 is compressed to one picture element. A color separation optical element 4 is constituted of a beam splitter and a total reflection prism, and performs color separation by receiving the compressed luminous flux 12 and enlarging it to three luminous fluxes in the array state of three primary colors R, G and B so as to respectively irradiate the set of R, G and B picture elements 5a, 5b and 5c of the display element 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color liquid crystal projection display device, and more particularly to a single plate type color liquid crystal projection display device which does not use a color filter.

[0002]

2. Description of the Related Art A color liquid crystal projection display device has a three-plate type using three liquid crystal display elements of red (R), green (G) and blue (B) and a single-plate type using one liquid crystal display element. There is. The three-plate type color liquid crystal projection display device is a system in which three liquid crystal display elements corresponding to three primary colors are used and combined by a prism or a dichroic mirror. The light utilization efficiency is good, but the device becomes large. On the other hand, the single plate type has an advantage that the device can be miniaturized because one liquid crystal display element is used.

In a conventional single-plate type color liquid crystal projection display device, for example, as shown in FIG. 6, the light from a light source 61 is condensed by a condensing optical system 62 and is irradiated on a liquid crystal display element 64 having a color filter 63. It is generally well known that the projection lens 65 is used to enlarge and project on the screen 66. Further, as disclosed in Japanese Patent Laid-Open Nos. 62-293222 and 293223, a single liquid crystal display element in which R, G and B pixels are two-dimensionally arranged is used, and light from a light source is passed through a diffraction grating By irradiating the R, G, and B pixels via light, there is a device in which the light use efficiency is improved without using a color filter.

Another example is JP-A-61-121032.
As disclosed in Japanese Patent Laid-Open No. 8 and 60-53838, light from a light source is color-separated by a prism or a dichroic mirror, and R,
There is one in which the G and B pixels are irradiated respectively.

[0005]

However, in the diffraction by the diffraction gratings described in JP-A-62-293222 and 293223, the 0th order, ± 1st order,
The light intensity becomes weaker in the order of ± second order. Therefore, R, G,
Since a large difference occurs in the amount of light incident on each of the B pixels, it is necessary to correct the amount of light, and the light utilization efficiency decreases. Also,
Even if the diffraction grating can be set so that the R, G, and B lights respectively enter the pixels, there is a problem that the color reproducibility deteriorates because crosstalk is always generated.

In the color separation by the dichroic mirror described in the above-mentioned Japanese Patent Laid-Open No. 61-210328, since the light is reflected a plurality of times by the tapered reflection optical path, the light loss is large and it is not practical. Further, in the color separation by the dichroic mirror described in Japanese Patent Laid-Open No. 4-60538, the microlens array collects light on the R, G, and B pixels of the liquid crystal display element. Since it is difficult to manufacture, there is a problem that crosstalk easily occurs.

It is an object of the present invention to provide a color liquid crystal projection display device capable of projecting and displaying a bright color image having good color reproducibility and reducing light amount loss and good light utilization efficiency.

[0008]

According to the present invention, there is provided a color liquid crystal projection display device in which R, G and B pixels are arranged in an array, respectively, and R, G and B pixels in the column direction are combined into one set for color display. And a beam compressor for reducing the illumination light flux of the liquid crystal display element by a cylindrical lens formed in an array corresponding to the set of R, G, B pixels, and a beam compressor for reducing the illumination light flux. And a color separation optical element which receives the luminous flux and separates it into luminous fluxes of three primary colors of red, green and blue, and emits the luminous flux to the set of R, G and B pixels respectively. In addition, the beam compressor,
The illumination luminous flux of the set of R, G, and B pixels (three pixels) is reduced to a luminous flux of one pixel, and the color separation optical element expands the reduced luminous flux to triple the luminous flux. This is a configuration in which color separation is performed into three primary colors.

[0009]

The present invention will be described below with reference to the drawings.

1 and 2 are views showing an embodiment of the present invention. In FIG. 1, an illumination light beam 10 from a light source 1 is condensed by a condensing optical system 2, and a condensed light beam 11 is reduced by a beam compressor 3 and then separated into R, G, and B by a color separation optical element 4. It is color-separated into three primary colors and is irradiated onto the liquid crystal display element 5, and is enlarged and projected on the screen 7 by the projection lens 6.

By the way, in the liquid crystal display element 5, as shown in FIG. 2, R, G, and B pixels are two-dimensionally arranged in an array, and a set of R, G, and B pixels 5a, 5b, in the column direction is formed. 5
Color display is performed by c.

Further, in FIG. 2, the beam compressor 3 is composed of a convex lens 3a and a concave lens 3b in which a plurality of cylindrical lenses are formed in an array, as shown in FIG. 3, for example. Each of the cylindrical lenses of the lenses 3a and 3b is formed corresponding to the pixel in the column direction of the liquid crystal display element, and the size of each of the cylindrical lenses of the convex lens 3a corresponds to three pixels in the column direction of the liquid crystal display element (one set of (R, G, B pixels). The convex lens and the concave lens reduce the size of three pixels of the incident light flux 11 into an array and emit the light. In addition, such a convex lens 3a and a concave lens 3b can be easily produced by, for example, embossing or molding used when producing a lenticular plate or a Fresnel lens.

Similar to the lens of the beam compressor 3 shown in FIG. 3, the color separation optical element 4 is formed in a horizontally long array corresponding to the R, G and B pixels in the column direction of the liquid crystal display element 5. There is. The size of the light flux 12 incident on the incident surface is equal to the size of the pixel, and the R, G, B light flux 1 from the exit surface is
Each size of 3 is equal to the size of a pixel.

The color separation optical element 4 includes a beam splitter 4a and total reflection prisms 4b, 4 as shown in FIG.
It is composed of c and. The beam splitter 4a has two reflecting surfaces x and y which are orthogonal to each other. The reflecting surface x reflects red (R) and transmits green (G) and blue (B), and the reflecting surface y is Reflects blue (B) and green (G)
And red (R). The red and blue luminous fluxes reflected by the reflecting surfaces x and y of the beam splitter 4a are reflected by the total reflection prisms 4a and 4b, and are emitted as R luminous flux and B luminous flux. Further, the green luminous flux transmitted through the beam splitter 4a is emitted as a G luminous flux.

In this way, the light beam 12 whose three pixels have been reduced to one pixel by the beam compressor is expanded three times by the color separation optical element 4 and color-separated into R, G, and B light beams, and the liquid crystal. Since the light is surely incident on each of the corresponding R, G, and B pixels of the display element, the color reproducibility is good and the light amount loss can be reduced.

FIG. 5 is a diagram showing another example of the color separation optical element. This color separation optical element 41 is composed of a prism 41a having a reflection surface x and a prism 41b having a reflection surface y, and like the color separation optical element 4 shown in FIG. The pixels are formed in a horizontally long array corresponding to the pixels. Here, if the reflecting surface x of the prism 41a reflects red and transmits green and blue, and the reflecting surface y of the prism 41b reflects blue and transmits green, the incident light flux 12 is Color separation into three primary colors of R, G and B is possible.

The color separation optical element described above can be manufactured by, for example, molding and then dichroic mirror processing by vapor deposition on the reflecting surface and assembling in an array.

[0018]

As described above, according to the present invention,
R, G, B pixels are two-dimensionally arranged in an array,
The R, G, and B pixels in the column direction are used as a set to use a liquid crystal display element for color display, and the luminous flux illuminating the liquid crystal display element is reduced in an array form from three pixels to one pixel. The magnified light flux is expanded into three primary colors of R, G, and B, and color separation is performed,
By making the R, G, and B light fluxes enter the R, G, and B pixels of the liquid crystal display element, respectively, it is possible to project and display a bright color image with good color reproducibility, light quantity loss and light utilization efficiency.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of the present invention.

2 is a sectional view schematically showing the beam compressor 3, the color separation optical element 4 and the liquid crystal display element 5 shown in FIG.

FIG. 3 is a perspective view of a beam compressor 3 shown in FIG.

4 is a cross-sectional view showing an example of the color separation optical element 4 shown in FIG.

FIG. 5 is a cross-sectional view showing another example of the color separation optical element.

FIG. 6 is an overall configuration diagram showing a conventional color liquid crystal projection display device.

[Explanation of symbols]

 3 Beam compressor 3a Convex lens 3b Concave lens 4,41 Color separation optical element 4a Beam splitter 4b, 4c Total reflection prism 5 Liquid crystal display element 5a, 5b, 5c R, G, B pixel 11, 12, 13 Luminous flux 41a, 41b Reflecting surface Having prism

Claims (2)

[Claims] 1. A liquid crystal display element, in which R, G, and B pixels are arranged in an array, respectively, to form a set of R, G, and B pixels in a column direction for color display, and the set of R and G pixels. , A beam compressor for reducing the illumination light flux of the liquid crystal display element by a cylindrical lens formed in an array corresponding to the B pixel, and a light flux reduced by the beam compressor for receiving the three primary colors of red, green and blue. A color liquid crystal projection display device, comprising: a color separation optical element that performs color separation into a light flux and emits the light to each of the set of R, G, and B pixels. 2. The beam compressor reduces an illumination light flux of the set of R, G, B pixels (three pixels) to a light flux of one pixel, and the color separation optical element is reduced in size. 2. The color liquid crystal projection display device according to claim 1, wherein the luminous flux is expanded into a triple luminous flux and color-separated into three primary colors.