JP2773086B2 - LCD projector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0010]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection type liquid crystal projector.

[0020]

2. Description of the Related Art Advances in liquid crystal materials and driving technology have led to
High-speed switching operation and fine processing become possible,
Liquid crystals have been widely used as display means for video information. In particular, recently, utilization as a projector capable of obtaining a large image with a small device by utilizing the characteristics of a liquid crystal panel has been promoted. FIG. 3 shows this type of color liquid crystal projector conventionally used.

After adjusting the optical path of the white light from the light source (1) by the mirror (2), the white light is separated into three primary colors by the dichroic mirror (3), and the liquid crystal panel (4R) driven by the video signal of each color. , (4G), and (4B). Each liquid crystal panel functions as a switch for controlling the amount of transmitted light with respect to incident light, and transmits the amount of light corresponding to a video signal for each picture element. The light transmitted through the LCD panel is returned to the dichroic mirror (5)
Combined as one color image with lens (6)
Is projected on a screen or the like.

FIG. 4 is a schematic diagram equivalently showing a liquid crystal panel used in the above liquid crystal projector, in which picture elements are arranged in a two-dimensional matrix on a glass substrate surface, and a switching element comprising a thin film transistor is provided for each picture element. An element (7) is provided for switching a display data signal supplied to the pixel electrode. In the drawing, (8) is a liquid crystal layer, and (9) is a common electrode opposed to the picture element electrode with the liquid crystal layer (8) interposed therebetween. Here, in the display operation, the scanning unit (10) of the liquid crystal driver turns on the switching elements (7) in the matrix form sequentially for each line, and outputs a data signal given from the data unit (11) of the liquid crystal driver. It is supplied to the liquid crystal layer (8) to control the light transmission of the liquid crystal layer.

[0050]

In the above-mentioned conventional liquid crystal panel, a switching element is required for each picture element in order to adopt an active driving mode. However, since picture elements are two-dimensionally arranged on the liquid crystal panel surface, there is no place to arrange a switching element such as a TFT (thin film transistor) except for a picture element area. It is formed on the upper left of the area. Therefore, the entire area occupied by the picture element cannot be effectively used for image display, and the amount of light contributing to the image is reduced, adversely affecting the image quality. There is a problem that the switched switching element portion becomes a point-like shadow, making the image very difficult to see.

The present invention has been made in view of such a point, and a liquid crystal projector for projecting a two-dimensional image with a liquid crystal panel for one line without using a liquid crystal panel having two-dimensionally arranged picture elements. I will provide a. Still another object of the present invention is to provide a liquid crystal projector in which the area of a picture element region is not reduced by a switching element for driving a picture element.

[0070]

In order to achieve the above object, according to the present invention, in a projection type liquid crystal projector, a liquid crystal panel is not arranged in a one-screen state in which picture elements are arranged two-dimensionally, but in a one-line state. The display image for one line is formed by adjusting the optical path with a reflecting mirror, and the reflecting surface of the reflecting mirror is displaced in synchronization with the video signal supplied to the liquid crystal panel for one line. And a drive mechanism for shifting the position of the reflected light is provided. In addition, at least three liquid crystal panels are provided corresponding to the three primary colors of R, G, and B to form a color projection device. Further, a switching element provided for each picture element is arranged outside a picture element area which does not affect image display.

[0080]

The light emitted from the light source passes through a linear liquid crystal panel to which a one-line video signal is input, and the transmitted light is projected on a screen or the like in a controlled direction by a reflecting mirror. At this time, since the reflecting surface of the reflecting mirror is displaced in synchronization with the video signal of one line input to the linear liquid crystal panel, a projected image is input when the video signal for one screen is input to the linear liquid crystal panel. As a result, one screen is formed.

[0090]

An embodiment of the present invention will be described below with reference to the drawings. Note that the same parts as those in the related art are denoted by the same reference numerals. In FIG. 1, the direction of white light emitted from a light source (1) is adjusted by a mirror (2), and then separated by a dichroic mirror (3) into R, G, and B of three primary colors. 3 installed
The light enters the liquid crystal panels (14R), (14G), and (14B). Each of the three liquid crystal panels (14R), (14G), and (14B) is configured as a one-line liquid crystal panel in which picture elements are linearly arranged, and one line is included in one screen of a projected image. 1
Make a line. Therefore, the number of picture elements constituting the liquid crystal panel is designed to be at least equivalent to the number of picture elements included in one line. Each linear liquid crystal panel is a video signal circuit (15)
And a video signal (15A) of each color corresponding to the three primary colors of R, G, and B and a synchronizing signal (15B) corresponding to the line are input to adjust the transmission amount of light of each color. Further, as shown in FIG. 2, each of the three linear liquid crystal panels has
A plurality of picture element electrodes (16) are linearly arranged on a transparent substrate such as glass, and a switching element is provided outside the area occupied by the picture element electrodes (16) arranged in a straight line.
(7) is formed. The switching element (7) can be constituted by a TFT using amorphous silicon, polysilicon or the like. In the linear liquid crystal panel as described above, since there is no adjacent picture element around the picture element area in one row as in the case where picture elements are two-dimensionally arranged, the switching element can be arranged outside the picture element area. Thus, it is possible to prevent the picture element region from being reduced by the switching element.

Each linear liquid crystal panel (14R), (14G), (14B)
Are transmitted by the dichroic mirror (5) to form an image for one line. The direction of reflection of this one-line image is adjusted by a reflector (12), and is projected on a screen surface through a lens (6). Here, a drive mechanism (13) for displacing the reflection surface is attached to the reflection mirror (12),
The reflection direction of the image composed of the three primary colors can be displaced. That is, the video signal circuit is also provided in the drive mechanism (13).
A synchronizing signal (15B) indicating one line is given from (15), the reflecting surface is displaced at a fixed angle in accordance with the synchronizing signal, and the projection position is sequentially shifted each time one line of video is reflected. Therefore, in a state where the video signal circuit (15) outputs a video signal to the line-shaped liquid crystal panel for each line and outputs a video of one screen, the projected image on the screen is also reflected on the reflection surface synchronized with the video signal of the line. , One screen is projected.

[0110]

As described above, according to the present invention, a two-dimensional image can be projected with a line-shaped liquid crystal panel, the panel can be reduced in size, and light can pass through the liquid crystal panel. The width of the optical path up to the reflecting mirror for guiding the reflected light to the projection surface may be sufficient to cover one line.
The size of the projection device can be further reduced, and a device convenient for carrying around can be obtained. Furthermore, a switching element for controlling the amount of light transmission of the picture element can be provided outside the picture element area, so that a reduction in the amount of light transmission can be prevented, and a high-quality projected image can be formed.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing one embodiment of a liquid crystal projector according to the present invention.

FIG. 2 is an equivalent circuit diagram of a liquid crystal panel used in the embodiment.

FIG. 3 is a schematic diagram of a conventional liquid crystal projector.

FIG. 4 is an equivalent circuit diagram of a liquid crystal panel used in a conventional liquid crystal projector.

[Explanation of symbols]

 3,5 Dichroic mirror 12 Reflector 13 Reflection surface drive mechanism 14R, 14G, 14B Line-shaped liquid crystal panel 15 Video signal circuit

Claims (3)

(57) [Claims] 1. A linear liquid crystal panel in which a plurality of picture elements are linearly arranged, an optical system for entering light from a light source into the linear liquid crystal panel, and a one-line video signal supplied to the linear liquid crystal panel. An image signal circuit, a reflecting mirror for guiding light transmitted through the liquid crystal panel to a projection surface, and a reflecting mirror driving mechanism for displacing a reflecting surface of the reflecting mirror in synchronization with an image signal; Is a liquid crystal projector characterized by sequentially shifting reflected light from a reflecting mirror in synchronization with a one-line video signal input to a liquid crystal panel. 2. The apparatus according to claim 1, wherein at least three linear liquid crystal panels are provided corresponding to the three primary colors of R, G, and B, and a video signal circuit inputs a video signal of a color corresponding to each linear liquid crystal panel. 2. The color liquid crystal projector according to claim 1, wherein the combined light of the light transmitted through each line-shaped liquid crystal panel is guided to a reflecting mirror. 3. The liquid crystal panel according to claim 1, wherein each picture element of the liquid crystal panel includes a switching element, and the switching element is disposed outside the picture element region.
2. The liquid crystal projector according to 1.