JPH06160854A - Liquid crystal video projector - Google Patents

Abstract

PURPOSE:To remove perspective from a projection screen for a liquid crystal video projector which is set after being shifted from the center of the screen to left, or right. CONSTITUTION:The projector 10 is provided with at least a metal halide lamp 20, a color liquid crystal display element 30 having an RGB color filter 32 attached on the incident side of a liquid crystal cell 33 at a prescribed interval T, a 1st means constituted of a projection lens 50 and for inclining the luminous flux L1 of the metal halide lamp 20 which is made incident on the liquid crystal cell 33 through the RGB color filter 32 by an angle of theta, a 2nd means for switching the picture element arrangement of the liquid crystal cell 33 to RGB, BRG, or GBR, a 3rd means for making color image light L2 transmitted through the liquid crystal cell 33 incident on the central part on the incident side of the projection lens 50 whose optical axis for emission is vertical to the surface of the screen 55.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal video projector device, and more particularly, to prevent a perspective image from being generated on a projected image even when projecting from a position deviating from the center in front of the screen to the left or right. Liquid crystal video projector device.

[0002]

2. Description of the Related Art In recent years, liquid crystal displays have been the most rapidly developed field, and various display sizes and systems have been developed as TV monitors and monitors for computers.

Further, the size of the ornamental screen is increased not only at the business level, but a TV monitor of a large CRT of 20 inches or more is also used at home, and the number of users of the large screen exceeding 40 inches is increasing year by year. . There is a liquid crystal video projector using a liquid crystal element as a method for realizing this large screen.

FIG. 7 is a plan view of an optical system of a typical liquid crystal video projector device 1, and the optical system will be briefly described with reference to FIG.

This liquid crystal video projector device 1 is a three-plate type for color, and its optical system has a metal halide lamp 2, a cold mirror 3, a filter 4, three liquid crystal cells 6a, 6b, 6c, and five liquid crystal cells. It is composed of dichroic mirrors 5a to 5e, a dichroic prism 7, and a projection lens 8. The optical system composed of these, after refracting the light flux emitted from the metal halide lamp 2 by the cold mirror 3, transmits the infrared rays and ultraviolet rays through the filter 4 to remove unnecessary light,
R with three dichroic mirrors 5a, 5b, 5c
Disperses into three primary colors of B and G, and each is divided into three liquid crystal cells 6
A, 6b and 6c are transmitted to form three color light fluxes of R, B and G, and these three color light fluxes are combined by a dichroic prism 7 and a magnified color image is projected by a projection lens 8.

[0006]

When projecting a color image on the screen using the liquid crystal video projector device 1, it is most ideal to install the liquid crystal video projector device 1 at the center position in front of the screen and project the color image. However, in some cases, the projection may have to be performed from a position deviated to the left or right of the center in front of the screen. When the liquid crystal video projector device 1 is projected toward the center of the screen from such a position that is deviated to the left or right, trapezoidal distortion occurs on the projection screen, or the liquid crystal video projector device 1 is deviated to the left or right. There is a problem in that if the image is projected perpendicularly to the screen surface from that position, the projected image will be perspecive, giving the viewer a feeling of being uncluttered.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and at least a metal halide lamp and an RBG color filter are mounted at a predetermined distance on the incident surface side of a liquid crystal cell. A color liquid crystal display element and a projection lens, and a light flux emitted from the metal halide lamp is vertically incident on the color liquid crystal display element, and the transmitted color light flux is enlarged and projected on a screen through the projection lens. In the liquid crystal video projector device, a first means for inclining the luminous flux of the metal halide lamp incident on the liquid crystal cell via the RBG color filter with respect to vertical incidence by + θ degrees or −θ degrees, and the first means. Corresponding to the operation of the means, the pixel electrode circuit of the liquid crystal cell is changed to R → B, B →
Second means for switching to G, G → R, or R → G, B → R, G → B, and corresponding to the operations of the first and second means, the liquid crystal cell is transmitted and tilted. And a third means for causing the colored light flux to enter the center of the light-incident side lens of the projection lens whose projection optical axis is perpendicular to the screen surface. It is a thing.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to facilitate the description of the liquid crystal video projector device of the present invention, a single plate type liquid crystal video projector device 10 will be briefly described.

FIG. 1 is a plan view of a single-plate liquid crystal video projector device 10 of the present invention when projected from the center in front of the screen.

The optical system of the single plate type liquid crystal video projector device 10 shown in FIG. 1 has at least a metal halide lamp 20, an RBG color filter 32 and a liquid crystal cell 3.
Color liquid crystal display element 3 to be described later attached to the incident side of
0 and a projection lens 50, and a light flux L ₁ emitted from the metal halide lamp 20 is formed into a color liquid crystal display element 3 including an RBG color filter 32 and a liquid crystal cell 33.
The color light flux L ₂ that has been made incident on 0 is magnified and projected on the screen via the projection lens 50.

FIG. 2 shows the color liquid crystal display device 30 described above.
3 is a side cross-sectional view of the color liquid crystal display element 30. FIG.

The color liquid crystal display element 30 includes a flat plate microlens 31, an RBG color filter 32, and a liquid crystal cell 3.
It is composed of 3 and 3.

The liquid crystal cell 33 includes a transparent counter substrate 34,
Black matrix 35, transparent common electrode 36, liquid crystal layer 37, transparent pixel electrode 38, thin film transistor (TFT)
39 and a transparent TFT substrate 40, and the liquid crystal layer 37 is injected between the transparent TFT substrate 40 made of glass or the like and the transparent counter substrate 34 which face each other at a predetermined interval.

The RBG color filter 32 is disposed on the incident side of the liquid crystal layer 37 via a transparent counter substrate 34 having a predetermined thickness so that the liquid crystal layer 37 is not affected by the absorption heat generated when absorbing unnecessary light. ing. Then, on the inner surface of the transparent counter substrate 34, a gap between dots to be emitted in the liquid crystal layer 37 is covered with a black substance to obtain a high-contrast image, and reflection of ambient light from the liquid crystal layer 37 is reduced. A black matrix 35 and a transparent common electrode 36 are provided. Further, a transparent pixel electrode 38 whose voltage is on / off controlled by a thin film transistor 39 is formed on the inner surface of the transparent TFT substrate 40. That is, by applying a voltage between each transparent pixel electrode 38 and the transparent common electrode 36 by the on / off operation of the thin film transistor 39, the liquid crystal layer 37 interposed between both electrodes 38, 36 can be driven. Is. This liquid crystal driving method includes a simple matrix method in which electrodes are arranged in columns and rows and the intersections thereof are controlled, and an active matrix method in which a thin film transistor functioning as a switch is attached to each pixel for control. However, the active matrix method is superior in terms of image quality. The liquid crystal cell 33 used in the single-plate liquid crystal video projector device 10 of the present invention is not limited to any driving method.

On the outer surface of the transparent counter substrate 34 of the liquid crystal cell 33, a flat plate microlens 31 having a plurality of minute lenses 31a arranged in a plane is laminated via an RBG color filter 32. The minute lens 31a of the flat plate microlens 31, the R, B, and G of the RBG color filter 32, and the RBG pixel of the liquid crystal cell 33 are precisely aligned and laminated.

The color liquid crystal display element 30 composed of these constituent members is arranged between the metal halide lamp 20 and the projection lens 50, and the luminous flux L ₁ (solid line) emitted from the metal halide lamp 20 is RBG as shown in FIG. The B-color light beam L ₁ which is vertically incident on the color filter 32 is incident on the B-color pixel electrode of the transparent pixel electrode 38 and is controlled and emitted as a B-color light beam L ₂ (solid line). The B-color light flux L ₂ is projected as B-color pixels on the screen 55 by the projection lens 50.

[0017] The above description, a single-plate type liquid crystal video projector apparatus 10 of the present invention, in the case of projecting from the center of the screen forward as shown in FIG. 1, the left or right from the phantom line C ₁ of the center of the screen The case of projecting from a position deviated to is described below.

FIG. 3 is a plan view showing the single-plate liquid crystal video projector device 10 installed and projected on a virtual line C ₂ which is displaced to the left of the virtual line C ₁ from the center of the screen, and FIG. 4 is shown on the right side. Although it is a plan view when it is installed and projected on the displaced virtual line C ₃ , the two drawings are different only in the direction of deviation and the description will be duplicated. Therefore, referring to FIGS. The explanation will focus on the case where the shift is to.

In FIG. 2 described above, the light flux L ₁ emitted from the metal halide lamp 20 when projecting from the center position of the screen is shown by a solid line, and the light flux L ₁ when projecting from the position shifted to the left is shown by a dotted line. ing. The light beam L ₁ when projected from the position shifted to the left side is inclined by θ degrees with respect to the vertically incident light beam L ₁ .

FIG. 5 is a diagram showing a specific embodiment of the first means for inclining the angle of θ.

In the figure, reference numeral 42 denotes two curved rails which are parallel to each other, and the grooves 4 formed on the respective facing surfaces thereof.
The metal halide lamp 20 is slidably held by 2a.

The curved rail 42 is curved along an arc drawn centering on the center point P of the color liquid crystal display element 30. Therefore, even if the metal halide lamp 20 is slid in the arrow direction along the groove 42a of the two curved rails 42, the metal halide lamp 20 emits light while keeping the distance between the color liquid crystal display element 30 and the metal halide lamp 20 constant. The light flux L ₁ can be tilted.

The angle θ at which the luminous flux L ₁ emitted from the metal halide lamp 20 inclined by θ degrees by the above method is incident on the RGB color filter 32 is θ = tan ⁻¹ (P / T). Here, P is the pixel pitch of the liquid crystal cell, and T is the distance (air conversion length) between the transparent pixel electrode and the RGB color filter.

The luminous flux L ₁ (dotted line) emitted from the metal halide lamp 20 in which the luminous flux L ₁ is inclined by θ degrees in this way
Is incident on the G region adjacent to the B region when the RGB color filter 32 is vertically incident as shown in FIG. 2, and the transmitted light flux L ₁ (dotted line) becomes the G color light, and passes through the liquid crystal layer 34. Then, the light is incident on the transparent pixel electrode 38 while being inclined.
However, the transparent pixel electrode 38 into which this G color light enters
Is the B pixel electrode at the time of vertical incidence and G
It is necessary to switch the signal circuit so that the G pixel electrode corresponds to the color light.

There is a second means for switching this signal circuit. Immediately, the signal circuit of the pixel electrode when the light beam L ₁ is vertically incident is switched to R → B, B → G, G → R.
It operates corresponding to the above-mentioned first means.

In the above description, the imaginary line C ₂ shifted to the left from the imaginary line C ₁ from the center of the screen shown in FIG.
When projecting from above, and when projecting from the virtual line C ₃ which is shifted to the right side shown in FIG. 4, the second means is R → G, B.
It goes without saying that the signal circuit must be switched to → R, G → B.

In this way, the incident light is controlled by the second means and becomes the color light flux L ₂ transmitted through the color liquid crystal display element 30 and enters the projection lens 50. At this time, the tilted G color light flux L ₂ (dotted line) and the projection lens 50 are displaced by the distance W.

There is a third means for correcting the displacement of the distance W. The third means is a means for causing the G color light flux L ₂ (dotted line) to enter the center of the light-entering side lens of the projection lens 50, and the projection lens 50 whose projection optical axis is substantially perpendicular to the screen is The G color light flux L ₂ (dotted line) is moved in parallel so as to enter the center of the light-incident side lens.

FIG. 6 is a diagram showing a concrete example of the third means.

In the figure, reference numeral 43 designates two linear rails parallel to each other, and the grooves 4 formed on the respective facing surfaces thereof.
The projection lens 50 is sandwiched by 3a so as to be slidable in the arrow direction.

The two linear rails 43 pass through the center point P of the liquid crystal display element 30 and are provided in parallel with the line AB parallel to the element surface. Therefore, the projection lens 50 can be shifted along the groove 43a of the two linear rails 43 by the distance W shown in FIGS.

As described above, by the first, second, and third means according to the present invention, the single-plate liquid crystal video projector device 10 is shifted to the left or right regardless of the central position in front of the screen. Even if the image is projected from a different location, the projected image projected on the screen does not have a perspecive effect, and a satisfying large screen can be enjoyed.

[0033]

As described above, the liquid crystal video projector device of the present invention includes at least a metal halide lamp, a color liquid crystal display element in which an RBG color filter is attached to the incident side of a liquid crystal cell at a predetermined interval, and projection is performed. A liquid crystal video projector device comprising a lens, wherein a luminous flux emitted from the metal halide lamp is vertically incident on the color liquid crystal display element, and the transmitted color image light is enlarged and projected on a screen by the projection lens. A first for tilting a light flux of the metal halide lamp which is incident on the liquid crystal cell via a light beam by + θ degrees or −θ degrees with respect to vertical incidence.
And the RBG pixel electrode of the liquid crystal cell as R → B, B
→ G, G → R, or second means for switching to R → G, B → R, G → B, and the color image light transmitted through the liquid crystal cell, the emission optical axis is perpendicular to the screen surface. By including the third means for making the light incident side lens center of the projection lens incident, the position where the liquid crystal video projector device is installed is shifted to the left or right regardless of the center of the screen. Can be installed and projected on the screen, which improves the usability of the LCD video projector device, and the projected image projected on the screen is also non-perspecive, allowing you to enjoy a satisfying large-screen home theater. .

[Brief description of drawings]

FIG. 1 is a plan view of a single-panel liquid crystal video projector device of the present invention when projected from the center in front of a screen.

FIG. 2 is a side sectional view of a color liquid crystal display element used in a single-panel liquid crystal video projector device.

FIG. 3 is a plan view when projecting from a position deviated to the left of the center position of the screen.

FIG. 4 is a plan view when projecting from a position shifted to the right from the center position of the screen.

FIG. 5 is a diagram showing a specific example of the first means according to the present invention.

FIG. 6 is a diagram showing a specific example of a third means according to the present invention.

FIG. 7 is a plan view of an optical system of a typical liquid crystal video projector device.

[Explanation of symbols]

 20 Metal Halide Lamp 30 Color Liquid Crystal Display Element 31 Flat Micro Lens 32 RGB Color Filter 50 Projection Lens 55 Screen L1 Luminous Flux of Metal Halide Lamp L2 Color Image Light

Claims (2)

[Claims] 1. A metal halide lamp, a color liquid crystal display element in which an RBG color filter is mounted on a light-incident surface side of a liquid crystal cell at a predetermined interval, and a projection lens, and a luminous flux emitted from the metal halide lamp is formed. In a liquid crystal video projector device for vertically entering the color liquid crystal display device and enlarging and projecting the transmitted color light beam on a screen through the projection lens, the metal halide which is made incident on the liquid crystal cell through the RBG color filter. Corresponding to the operation of the first means for inclining the luminous flux of the lamp by + θ degrees or −θ degrees with respect to the vertical incidence, the pixel electrode circuit of the liquid crystal cell is changed to R → B, B. → G, G → R, or R → G,
Second means for switching from B to R and G to B, and corresponding to the operations of the first and second means, a color light beam which is transmitted through the liquid crystal cell and is inclined, has a projection optical axis whose screen is the screen. A liquid crystal video projector device comprising: a third means for making light incident on the center of the light-incident side lens of the projection lens which is perpendicular to the surface. 2. The inclination angle θ of the luminous flux of the metal halide lamp incident on the liquid crystal cell through the RGB color filter is θ = tan ⁻¹ (P / T) P: pixel pitch of the liquid crystal cell T: transparent pixel The liquid crystal video projector device according to claim 1, wherein the liquid crystal video projector device is represented by a distance (air conversion length) between the electrode and the RBG color filter.