JPH02101424A - Projecting type display device - Google Patents

Abstract

PURPOSE:To display a high-brightness, high-contrast, high-quality picture by employing an active matrix-type liquid crystal display element possessing a picture element electrode with comb-shaped structure as an optical valve, and enlarging and projecting a picture from the optical valve through a schlieren optical system. CONSTITUTION:The picture element electrode for the active matrix-type liquid crystal display element used as the optical valve 10 is produced into a comb- shaped electrode. The active matrix-type liquid crystal display element creates periodical refraction factor distribution in response to the repeated pitch of the comb-shaped electrode. A projection picture formed by the active matrix-type liquid crystal display element is enlarged and projected through the schlieren optical system 4. Thus, a high-brightness, high-contrast, high-quality picture can be displayed.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a projection display device using an active matrix liquid crystal display element as a light valve.

B. Summary of the Invention The present invention provides a projection display device using an active matrix liquid crystal display element as a light valve, in which an image projected by the light valve is magnified and projected through an IJ-len optical system. , which enables high-brightness, high-contrast, high-quality display, and aims to improve brightness and image quality.

C. Prior Art Conventionally, a large number of systems have been proposed and developed for projection display devices using light valves. However, some of the methods (for example, E
With the exception of the idophor method and the Ta1aria method, almost no products have been commercialized.

In the above Eidophor method and Ta1aria method,
As shown in FIG. 6A and FIG. 7A, the projection lens (3
1) an oil film is used as a light valve (30), (40) for the image to be projected onto the screen (32);
A pair of masks with complementary slind patterns (
33) A Schlieren optical system (36) having a structure in which a converging lens (35) is installed between (34) and the image of one mask (33) is formed on the other mask (34).
The light valves (30) and (40) are arranged between the converging lens (35) and the other mask (34), and the light from the light source (38) is directed to one of the Schlieren optical systems (36). The light enters the light pulp (30), (40) through the mask (33) and the converging lens (35), and the disturbance of the light corresponding to the projected image in the light valve (30), (40) causes the light to enter the other light bulb (30), (40). The image is projected onto the screen (32) via the projection lens (31) as light leaking from the slit pattern of the mask (34).

Here, in the Eidophor method shown in FIG. 6A, an optical deformation indicating a projected image is given to the light valve (30) using an oil film, and the other mask (34) of the Schlieren optical system (36) is As shown with diagonal lines in Figure 6B, which shows the light intensity distribution of
An image based on the leakage component of /2 can be projected onto the screen (32).

In addition, in the Ta1aria method shown in FIG.
), the light intensity distribution on the other mask (34) is shown with diagonal lines in FIG.
Images resulting from two or more light leakage components are displayed on the screen (32).
can be projected to.

In recent years, projection-type display devices that use direct-view active matrix liquid crystal display panels as light valves have been proposed and are being put into practical use.
As shown in the figure, the light emitted from light a (50) via the condenser lens (51) is divided into three primary color separation systems (52).
Each optical pulp (53R), (53G) separates into three primary color light components of red light component R1 green light component G and blue light component B to provide a projection image of three primary colors.

(53B), the above light valve (53R), (5
The three primary color light components that have passed through 3G) and (53B) are combined in a three primary color synthesis system, and the three primary color synthesis system (54) projects the combined light as projection light onto a screen (56) via a projection lens (55). In the projection type color display device that projects a color image onto the screen (56), each of the light valves (53R), (53G), (53B) provides a projected image of the three primary colors.
) has been proposed in which a direct-view active matrix liquid crystal display panel is used as is.

Note that in the projection type color display device, the light i (5
0) is a halogen lamp (50a) in front of a concave mirror (50a).
b), and the three primary color separation system (52) includes two dichroic ink mirrors (52a) and (52b).
), and furthermore, the three primary color synthesis system (54) is composed of a dichroic prism. In addition, each of the above light valves (53R), (53G), (53
The active matrix type liquid crystal display panel used as B) is, for example, a transparent glass plate on which pixel electrodes are formed in an XY matrix shape and connected to nonlinear elements such as thin film transistors arranged at the cross points of signal lines and scanning lines. An XY matrix type liquid crystal display panel is known in which liquid crystal is sealed between a transparent glass plate and a transparent glass plate on which a counter electrode is formed.

D. Problems to be Solved by the Invention Projection display devices that use a trix-type liquid crystal display panel directly as a light valve have the following problems.

That is, nearly 1/3 of the total amount of light is lost due to the polarizer and detection photons, making it impossible to make the projection screen sufficiently bright.

Furthermore, the contrast is determined by the contrast of an active matrix liquid crystal display panel used as a direct view type, and sufficient contrast cannot be obtained.

Furthermore, the pixel pattern is noticeable due to magnification and projection, resulting in poor image quality.

Therefore, in view of the conventional situation as described above, the present invention aims to enable high-quality display with high H degree and high contrast in a projection type display device using an active matrix type liquid crystal display element as a light valve. An object of the present invention is to provide a projection type display device having a novel configuration in which projection light from an active matrix liquid crystal display element used as a light valve is projected through a Schlieren optical system.

By the way, in order to achieve the above-mentioned object, the projection type display device according to the present invention uses an active matrix type liquid crystal display device having pixel electrodes having a comb-shaped electrode structure. It is characterized by comprising a light valve using a display element and a schlieren optical system in which the light valve is disposed in an optical path, and an image projected by the light valve is enlarged and projected via the schlieren optical system. .

F Function In the projection display device according to the present invention, the pixel electrode of the active matrix liquid crystal display element used as a light valve has a comb-shaped electrode structure, so that periodic refraction corresponding to repeated pinching of the comb-shaped electrode is achieved. A rate distribution occurs in the active matrix type liquid crystal display element.

G. Example Hereinafter, an example of a projection type display device according to the present invention will be described in detail with reference to the drawings.

The projection type display device of the embodiment shown in FIG.
A matrix type liquid crystal display element (10) is used as a light valve, and a converging lens ( The Schlieren optical system (4) has a structure in which the image of one mask (1) is formed on the other mask (2) by installing a mask (3).
The light valve, that is, the active matrix liquid crystal display element (1o) is disposed between the converging lens (3) of the lens (3) and the other mask (2), and the light from the light source (5) is transferred to the Schlieren optical system (2). 4) through one of the masks (1) and the converging lens (3) to the active matrix type liquid crystal display element (1o), and the image corresponding to the projected image on the active matrix type liquid crystal display element (10). The L image is projected onto the screen (7) via the projection lens (6) as light leaking from the slit pattern of the other mask (2) due to light disturbance.

In this embodiment, the active matrix type liquid crystal display element (10) used as the light valve has a pixel electrode structure as shown in FIG.
Pixel electrodes (14) connected to nonlinear elements (13), such as thin film transistors, arranged at the cross points of the and scanning lines (12) are each formed in a comb-like electrode structure. The cross-sectional structure of this active matrix liquid crystal display element (10) is shown in FIG. 3A.
As shown in , a transparent glass plate (15) on which the pixel electrode (14) is formed, and a transparent glass plate (17) on which a counter electrode (16) to the pixel electrode (14) having the comb-shaped electrode structure is formed. A liquid crystal (18) is sealed between the two.

In the active matrix liquid crystal display element (10) having the pixel type Ifi (14) with a comb-shaped electrode structure, the counter electrode (16) is fixed at a certain potential, and the potential applied to the pixel electrode (14) is When the potential difference is set to exceed the potential difference of the liquid crystal (18) with respect to the counter electrode (16), a refractive index distribution as shown in FIG. 3B occurs. The difference in optical path length due to this refractive index distribution is Δn−d
(Δn=n@-no, d: cell thickness), and the resulting diffraction pattern becomes constructive interference in the angle θ direction that satisfies P-sinθ=Δn-d [where P is the comb-like pixel electrode ( 14) spatial period]. This achieves the same effect as the above-mentioned Ta1aria method that uses an oil film as a light valve, and the pixel electrode with the comb-shaped electrode structure (
By enlarging and projecting the projected light from the ita light bulb via the Schlieren optical system (4),
High-brightness, high-contrast, high-quality display can be performed on the screen (7).

Here, in the case of Ta1aria method 2, the maximum contrast is obtained when the unevenness of the oil film is 3/4λ, and when this condition is applied to this example, d = G ) t m becomes Δr + Li0.03, and generally liquid crystal Δn(n.

-n. ) is about 0.08 to 0.2, so the above value is fully achievable.

In the XY matrix type night crystal panel, since each pixel is regularly arranged in the XY force directions, the interference pattern corresponding to the spatial frequency is also superimposed on the other mask ( 2) Imaged on. Then, the pixel electrode (14
), as shown with diagonal lines in Fig. 4 showing the light intensity distribution on the other mask (2), the interference by each pixel in the interference peak due to the comb-shaped electrode structure is By extracting only the zero-order term of , it is possible to remove the pixel pattern from the image projected on the screen (7). Since 1) and (2) are slit patterns, in principle only one dimension (X or Y only) is possible. By similarly arranging the slit pattern of the mask in the diagonal direction,
It can also function as a two-dimensional low-pass filter.

In addition, in the above-mentioned embodiment, a transmission type structure is used in which light from the light source (5) passes through an optical pulp using an active matrix liquid crystal display element (10) having a pixel electrode (14) having the above-mentioned comb-shaped electrode structure. However, the projection type display device according to the present invention is not limited to the above-described embodiments, and may also have a reflective type configuration, for example, as shown in FIG. 5.

In the projection type display device of the embodiment shown in FIG.
A reflective bar (21) inclined at about 45' l with respect to the optical axis of the
2) are arranged in parallel, and the light source (23) is connected to the reflective bar (22).
), the light tA (23) is reflected so that the light reflected by the optical pulp, ie, the active matrix liquid crystal display element (20), is converged onto the reflection bar (23). bar (22), converging lens (2
1) Active matrix liquid crystal display element (20)
The above-mentioned reflection bar (
22) The utilization rate of light from the light source (23) is increased by projecting the leaked light component from between the light source (25) using the projection lens (24) to create a reflective configuration. be able to.

H Effects of the Invention In the projection display device according to the present invention, the pixel electrode of the active matrix liquid crystal display element used as a light valve has a comb-shaped electrode structure, so that the pixel electrode of the active matrix liquid crystal display element used as a light valve has a comb-shaped electrode structure. A refractive index distribution is generated in the active matrix liquid crystal display element, and by enlarging and projecting the image projected by the active matrix liquid crystal display element through a schlieren optical system, a high-brightness, high-contrast, high-quality display is achieved. It can be performed.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram conceptually showing the configuration of an embodiment of a projection display device according to the present invention constructed as a transmission type, and Fig. 2 shows an active matrix liquid crystal display element used in the above embodiment. FIGS. 3A and 3B are schematic plan views showing the structure of the pixel electrode of the active matrix type liquid crystal display element, and FIGS. FIG. 4 is a schematic diagram showing the distribution of the refractive index on the mask of the above-mentioned Schlieren optical system using an XY matrix type liquid crystal panel, and FIG. FIG. 1 is a schematic diagram conceptually showing the configuration of an embodiment in which a projection display device is configured as a reflective type. FIGS. 6A and 6B are schematic diagrams showing the basic structure of a conventional Eidophor projection display device using a schlieren optical system, and the distribution of light intensity on the mask of the schlieren optical system. The schematic diagrams, Figures 7A and 7B, are Ta1ari using Schlieren optical system.
A schematic diagram showing the basic structure of a conventional a-type projection display device and a schematic diagram showing the distribution state of light intensity on the mask of the above-mentioned Schlieren optical system. 1 is a schematic diagram showing the configuration of a conventional projection type color display device configured as a bulb.

Claims (1)

[Scope of Claims] The light valve includes a light valve using an active matrix liquid crystal display element having pixel electrodes with a comb-shaped electrode structure, and a Schlieren optical system in which the light valve is disposed in an optical path. A projection-type display device, characterized in that the projected image is enlarged and projected via the Schlieren optical system.