JPH1062784A - Projection liquid crystal display and manufacture of hologram element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a projection liquid crystal display device and a hologram element therefor, having a relatively good utilization factor by using it as a color separating and image-forming means and having less restriction for being assembled into an optical system and being inexpensive. SOLUTION: A hologram element 14 separates incident white light into three primaries of red, green, and blue, and forms a reproduced image (real image) on liquid crystal display elements 15 by making them incident onto each corresponding picture element on the liquid crystal elements 15. The hologram element 14 makes picture elements of a specific color of the liquid crystal elements 15 transmissive and also the other colors non-transmissive, and lets the specific color pass through the liquid crystal elements in this state, and forms interference fringes by making a substrate for the hologram irradiated with the transmitted light as light of an object body including reference light, and then picture elements of other colors are also similarly made by successively forming interference fringes corresponding to the colors.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection type liquid crystal display device using a hologram element as a color separation means, and more particularly to a hologram element having a function of forming a reproduced image on each pixel of the liquid crystal display element. The present invention relates to a projection type liquid crystal display device and a method for manufacturing a hologram element used therefor.

[0002]

2. Description of the Related Art As a liquid crystal display device, there is a projection type display device (liquid crystal projector) for projecting and displaying an image on a screen together with a direct view type display device for directly viewing a liquid crystal display element (liquid crystal light valve, liquid crystal display panel). . This projection type liquid crystal display device separates white light emitted from a light source into primary colors for color display, guides each color light to a pixel (liquid crystal cell) of a liquid crystal display element corresponding to the color, and reproduces the light here. After modulation according to the image, the image is projected and enlarged on a screen to display a color image. Such a projection type liquid crystal display device has a red (Red = R) and a green (Green = R).
G), a single-panel system using one liquid crystal display element with color separation means of blue (Blue = B), and three monochrome liquid crystal panels for each of the red, green and blue optical paths It is broadly divided into three-plate systems.

[0003] Among them, in a single-panel projection display device,
In many cases, liquid crystal display elements developed for direct-view type liquid crystal display devices are diverted, but the liquid crystal display elements applied to this direct-view type liquid crystal display device are generally bonded with color filters to realize color display. Configuration.

[0004]

However, the conventional liquid crystal display device in which the color filter is bonded to a liquid crystal display element has the following problems. That is, when a color filter is used, a red color filter is arranged in a pixel that displays red, and light of other colors (green and blue) is absorbed or reflected by the red color filter. This is the same for the green and blue color filters. Therefore, only one third of the incident light to the liquid crystal display element can be used in the color filter system, and the light use efficiency is lower than in the case where the same light source is used in the three-plate system,
There is also a problem that the brightness of the screen is similarly reduced to one third. To increase the brightness, the output of the light source may be increased, but this will cause a rise in temperature due to light absorption. That is, in a liquid crystal display device using a color filter, there is a limit to brightening a screen.

As a method for solving the drawbacks of such a color filter, a method of performing color display using a dichroic mirror and a microlens without bonding the color filters (for example, Japanese Patent Application Laid-Open No. Hei 4-60538).
Reference). According to this method, white light emitted from a white light source is separated by a dichroic mirror arranged at an inclination for each of the three primary colors, and the separated light of each color is applied to each pixel of a liquid crystal display element via a microlens. Is to be incident. However, according to this method, the structure of the set (optical system) becomes large, or color mixture (noise) occurs.
And the color purity is reduced. Further, since an expensive microlens is required, there is a problem that the entire liquid crystal display device becomes expensive.

SUMMARY OF THE INVENTION The present invention has been made in view of such a problem. A first object of the present invention is to use a hologram element as a color separation means, so that light use efficiency is improved, and a set structure can be reduced in size. An object of the present invention is to provide an inexpensive projection-type liquid crystal display device that can prevent a decrease in color purity due to color mixing.

A second object of the present invention is to provide a method of manufacturing a hologram element which can easily realize the above-mentioned projection type liquid crystal display device.

[0008]

According to the present invention, there is provided a projection type liquid crystal display device comprising a light source for emitting white light and a plurality of pixels corresponding to primary colors for color display arranged regularly. A display element and a hologram element having interference fringes adapted to the arrangement of the pixels and colors of the liquid crystal display element, and a plurality of white light emitted from the light source adapted to the arrangement of the pixels and colors of the liquid crystal display element. Color separation to separate the primary color light into
Imaging means.

A method of manufacturing a hologram element used in a projection type liquid crystal display device according to the present invention is a method of manufacturing a hologram element, wherein a plurality of pixels corresponding to primary colors for color display are regularly arranged. The substrate for the hologram element is selectively exposed using an exposure mask suitable for the arrangement to produce a hologram element in which the color arrangement of the reproduced image conforms to the arrangement of pixels and colors of the liquid crystal display element.

As the exposure mask, for example, a liquid crystal display element for a projection type liquid crystal display device or a color filter having the same arrangement of pixels and colors as the liquid crystal display element is used. When a liquid crystal display element is used as an exposure mask, a pixel of a specific color of the liquid crystal display element is set to a transmissive state, and the other colors are set to a non-transmissive state. Light is transmitted, and this is used as object light to irradiate the hologram element substrate together with the reference light to form interference fringes. Then, interference fringes corresponding to the colors are sequentially formed for pixels of other colors in the same manner. do it. When a color filter is used as an exposure mask, interference light corresponding to each color may be formed by irradiating light transmitted through the color filter as object light together with reference light to a hologram element substrate. Good.

In the projection type liquid crystal display device according to the present invention, the white light radiated from the light source is separated for each primary color in the hologram element in which interference fringes conforming to the arrangement of pixels and colors of the liquid crystal display element are formed. The reproduced image is formed on the liquid crystal display element.

[0012]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows a schematic configuration of a projection type liquid crystal display device 10 according to an embodiment of the present invention. The projection-type liquid crystal display device 10 according to the present embodiment includes a white light source 11 that emits white light, a reflecting mirror (reflector) 12 that is, for example, a spherical mirror disposed on the back of the white light source 11, and is disposed on the front of the white light source 11. Condensing lens 13, a hologram element 14 as color separation / imaging means disposed on the front of the condensing lens 13, a liquid crystal display (LCD) disposed on the front of the hologram element 14.
y) 15, a projection lens 16 arranged on the front surface of the liquid crystal display element 15 and a screen 17 for image formation.

The white light source 11 may be any as long as it can emit white light including the three primary colors of red, green and blue. For example, a metal halide lamp, a halogen lamp, a xenon lamp or the like is used. The condenser lens 13 condenses the white light emitted from the white light source 11 and converts the white light into parallel light.
It leads to 4.

The hologram element 14 is not of the type in which the diffraction efficiency does not depend on the wavelength (that is, the type in which only a specific wavelength is diffracted like a Lippmann hologram and the other wavelengths are not diffracted). Hologram element). As such a hologram element, there are, for example, a relief method, a phase method, an amplitude method, and the like. Hologram element 14
For example, a photopolymer (Omnidex 352 manufactured by DuPont) is used as an element material of the liquid crystal display, and a plurality of interferences corresponding to a color arrangement matching a pixel and color arrangement of a liquid crystal display element are performed by a method described later. Stripes are formed. As shown in FIG. 2, the hologram element 14 according to the present embodiment converts the white light condensed by the condensing lens 13 into the pixel arrangement of the liquid crystal display element 15 for each of the three primary colors of red, green and blue. The liquid crystal display device 15 has a function of separating the light at an angle suitable for the above and transmitting the light to the liquid crystal display element 15 side, and making the transmitted light incident on each corresponding pixel of the liquid crystal display element 15. That is, the hologram element 14
Has a function of separating incident white light into primary colors and forming a reproduced image (real image) on the liquid crystal display element 15.

As shown in FIG. 3, the liquid crystal display element 15 has pixels (liquid crystal cells) 15 corresponding to three colors of red, green and blue.
a, 15b, 15c for example delta (triangle)
They are arranged in a regular pattern. Specifically, the liquid crystal display element 15 has a liquid crystal layer sealed between two glass substrates, and has three types of signal electrodes (that is, three types of signal electrodes constituting a matrix electrode structure for driving the liquid crystal layer). It has a structure in which the pixels 15a to 15c) shown in FIG. 3 are arranged on the inner surfaces of the glass substrates facing each other. Pixel 1
Each of the three types of signal electrodes 5a to 15c is formed of a transparent conductive film, and receives a drive signal of each color of red, green, and blue, and outputs the signals of the hologram element 1 described above.
The light of the corresponding color is incident through the reference numeral 4. That is, the intensity of the light of each color incident on each of the three types of signal electrodes is modulated according to the input state of the drive signal to each signal electrode.

The projection lens 16 combines the light modulated and transmitted by the liquid crystal display element 15 and magnifies and forms an image on a screen 17.

Next, a specific method for manufacturing the hologram element 14 according to the present embodiment will be described with reference to FIGS. 4 and 5A to 5C. In this method, a plurality of pixels corresponding to the above-described primary colors for color display are arranged regularly (in this embodiment, in a delta shape), and a configuration suitable for the arrangement of pixels and colors of the liquid crystal display element 14 is adopted. A hologram element 14 having a color arrangement of a reproduced image conforming to the arrangement of pixels and colors of the liquid crystal display element 15 is prepared by preparing an exposure mask having Is made.

As the exposure mask, for example, the liquid crystal display element 15 itself shown in FIG. 4 is used. In this method, first, as shown in FIG.
5, the pixel 15c of a specific color, for example, a blue pixel 15c is in a transmissive state, and the pixels 15a and 15b of other colors are in a non-transmissive state, and blue light is transmitted from the liquid crystal display element 15 in this state. The hologram substrate 14a is irradiated with the object light Ob via the imaging optical system 18 as the object light Ob. The reference light Ref is incident on the substrate 14a together with the object light Ob, and a first interference fringe is formed by irradiation of these two light beams. Next, interference fringes corresponding to the colors of pixels of other colors are similarly formed. In other words, as shown in FIG. 5B, the red pixel 15a of the liquid crystal display element 15 is made to be in a transmissive state, and the pixels 15b and 15c of other colors are made to be in a non-transmissive state. 15 through which red light is transmitted and illuminated as object light Ob on the hologram substrate 14a together with the reference light Ref to produce a second light.
Is formed. Thereafter, as shown in FIG. 5 (c), the blue pixel 15c of the liquid crystal display element 15 is set to a transmissive state, and the pixels 15a and 15b of the other colors are set to a non-transmissive state. A third interference fringe is formed by transmitting blue light from the substrate 15 and irradiating the blue light as object light Ob together with the reference light Ref to the hologram substrate 14a. Thus, the hologram element 15 having the interference fringes for each of the three primary colors is formed. Incidentally, the reference light Ref used in each step may be the same as the transmitted light of the liquid crystal display element 15, and FIG.
As described above, white light including red, green, and blue light may be used.

In the above embodiment, the liquid crystal display element 15 itself is used as the exposure mask. However, any mask having the same arrangement of pixels and colors as the liquid crystal display element 15 may be used. As shown in FIG. 6, a color filter may be used. That is, a color filter 19 having the same arrangement of pixels and colors as the liquid crystal display element 15 is prepared.
The hologram substrate 14a is irradiated with the light transmitted through 9 as object light Ob via the imaging optical system 18. The reference light Ref is incident on the substrate 14a together with the object light Ob,
An interference fringe corresponding to each color is formed by irradiation of a light beam. Also in this method, the reference light Ref may be the same as the transmitted light of the color filter 19, or may be white light including red, green, and blue light, as in the case of using the liquid crystal display element 15.

In the projection type liquid crystal display device 10 of this embodiment using the hologram element 14 manufactured by such a method, the white light emitted from the white light source 11 and reflected by the reflecting mirror 12 is collected. After being converged by the optical lens 13 to become parallel light, it is incident on the hologram element 14. Red of white light incident on the hologram element 14,
The three primary color components of green and blue are separated at an angle suitable for the pixel arrangement of the liquid crystal display element 15, respectively.
And the corresponding pixels 15a of the liquid crystal display element 15
~ 15c. That is, the hologram element 14
(Real image) is formed on the liquid crystal display element 15.
The light of the three primary colors incident on the liquid crystal display element 15 is spatially modulated for each color, and then guided to the projection lens 16. The modulated light that has entered the projection lens 16 is synthesized here, and is enlarged and formed on a screen 17. Thus, a color image is displayed.

The projection type liquid crystal display device 1 according to the present embodiment.
In the case of 0, a color filter,
Since an inexpensive hologram element 14 is used without using a dichroic mirror / microlens, incident light is not blocked by absorption and reflection as in the case of using a color filter. It can be used efficiently. Further, color separation suitable for the pixel arrangement of the liquid crystal display element (delta arrangement in the present embodiment) can be realized without restricting the configuration of the set (optical system), and a bright color image display with good color reproducibility can be realized. There is an effect that can be performed. Further, a reproduced image (real image) is formed on the liquid crystal display element 15 by the hologram element 14.
Can efficiently form an image, so that an expensive microlens is not required, and an inexpensive projection type liquid crystal display device 10 can be formed.
There is also an effect that can be realized.

According to the method of manufacturing the hologram element, the hologram element 14 is manufactured using an exposure mask (the liquid crystal display element 15 itself or the color filter 19) adapted to the arrangement of pixels and colors of the liquid crystal display element 15. The hologram element 14 has a configuration in which the color arrangement of the reproduced image matches the arrangement of the pixels and colors of the liquid crystal display element 15.
Can be easily realized. In addition, if the wavelength of the transmitted light (object light Ob) at the time of creating the hologram is matched with the spectrum of the white light source 11 (FIG. 1), there is an effect that the emission energy can be used efficiently.

Although the present invention has been described with reference to the embodiment, the present invention is not limited to the above-described embodiment and can be variously modified. For example, in the above embodiment, a delta (triangle) is used as the liquid crystal display element 15.
Although a pixel array having a pixel shape has been described, another pixel array (for example, a stripe shape) may be used, and interference fringes of the hologram element 14 may be formed according to the pixel and color array.

In the above embodiment, an example is described in which a transmission type hologram element in which diffracted light is emitted to the opposite side to the light source with the hologram surface as a boundary is applied. Hologram element can also be used. The reference light for producing the reflective hologram element may be incident from a direction conjugate with the reference light for producing the transmission hologram element.

Further, in the above embodiment, the interference fringes of the hologram element 14 are formed optically by two-beam interference. However, interference fringes suitable for the arrangement of pixels and colors of the liquid crystal display element are calculated by a computer. You can also ask. In this computer generated hologram, a hologram element similar to that of the above embodiment can be manufactured by adding the conditions described in the above embodiment at the time of calculation.

[0027]

As described above, according to the projection type liquid crystal display device of the present invention, a hologram in which interference fringes according to the arrangement of pixels and colors of a liquid crystal display element are formed as color separation / imaging means. The hologram element is used to separate the incident light for each primary color, and each color light is made to enter the corresponding pixel of the liquid crystal display element, so that the incident light can be used efficiently and the projection is inexpensive. Type liquid crystal display device can be realized. In addition, it is possible to perform color separation and imaging suitable for the arrangement of pixels and colors of a liquid crystal display element without restricting the configuration of a set (optical system), and to display a bright color image with good color reproducibility. There is an effect that can be performed.

According to the method of manufacturing a hologram element for a projection type liquid crystal display device according to the present invention, an exposure mask (liquid crystal display element itself or color filter) having a configuration corresponding to the arrangement of pixels and colors of the liquid crystal display element is provided. Etc.), the color arrangement of the reproduced image (real image) is adapted to the arrangement of pixels and colors of the liquid crystal display element, and a hologram element having color separation and imaging functions can be easily manufactured. Can be made. Further, if the wavelength of the transmitted light (object light) at the time of hologram creation is matched with the spectrum of the light source of the set, there is an effect that the emission energy can be used efficiently.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a schematic configuration of an entire projection type liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is a configuration diagram for explaining functions of a hologram element used in the display device shown in FIG.

FIG. 3 is a diagram illustrating an example of a pixel array of a liquid crystal display element used in the display device illustrated in FIG.

FIG. 4 is a configuration diagram for explaining a manufacturing process of the hologram element according to one embodiment of the present invention.

FIG. 5 is a view for explaining a light transmitting state of each step of the liquid crystal display element in a hologram element manufacturing process described in FIG.

FIG. 6 is a configuration diagram for explaining a manufacturing process of a hologram element according to another embodiment of the present invention.

[Explanation of symbols]

11: white light source, 12: reflecting mirror, 13: condenser lens, 1
4 Hologram element 15 Liquid crystal display (LCD), 16 Projection lens, 1
7 ... Screen

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location H04N 9/31 H04N 9/31 C

Claims (4)

[Claims] 1. A light source that emits white light, a liquid crystal display element in which a plurality of pixels corresponding to primary colors for color display are regularly arranged, and an arrangement of pixels and colors of the liquid crystal display element. A hologram element having a suitable interference fringe, the white light emitted from the light source is separated into a plurality of primary color lights so as to conform to the arrangement of pixels and colors of the liquid crystal display element, and the reproduced image is divided into the liquid crystal. A projection type liquid crystal display device comprising a color separation / imaging means for forming an image on a display element. 2. A method of manufacturing a hologram element used as a color separation / imaging means of a projection type liquid crystal display device, comprising a plurality of pixels regularly arranged corresponding to primary colors for color display. The substrate for the hologram element is selectively exposed using an exposure mask having a configuration adapted to the pixel and color arrangement of the display element, and the color arrangement of the reproduced image conforms to the pixel and color arrangement of the liquid crystal display element. A method for producing a hologram element for use in a projection-type liquid crystal display device, characterized in that a hologram element is produced. 3. A liquid crystal display element for a projection type liquid crystal display device is used as the exposure mask, and a pixel of a specific color in the liquid crystal display element is set to a transmissive state and other colors are set to a non-transmissive state. A light of a specific color is transmitted from the liquid crystal display element in this state, and this is used as object light to irradiate a substrate for a hologram element together with reference light to form interference fringes. Then, the same applies to pixels of other colors. 3. The method according to claim 2, wherein interference fringes corresponding to the colors are sequentially formed. 4. A color filter having the same pixel and color array as a liquid crystal display element for a projection type liquid crystal display device is used as the exposure mask, and light transmitted through the color filter is used as object light and a hologram together with reference light. 3. The method of manufacturing a hologram element used in a projection type liquid crystal display device according to claim 2, wherein an interference fringe corresponding to each color is formed by irradiating the element substrate with light.