JP2754031B2 - Projection type liquid crystal display - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection display apparatus having a light source unit having a discharge lamp that emits light by applying a voltage between a pair of electrodes.

[Conventional technology]

A conventional projection type liquid crystal display device is a projection type color display device (1986) using a liquid crystal light valve using a halogen lamp.
"LCD Full Color Video Projector," published in Society for Information Display's technical papers, pp. 375-378, May 2005)
Etc.

[Problems to be solved by the invention]

However, the conventional projection display device does not have sufficient brightness, and the color tone (color reproducibility) as image quality and the color temperature of white (the standard color temperature of NTSC of a television receiver is 6500K) However, it is difficult to obtain an image quality comparable to that of a television receiver, and furthermore, uniformity (including color uniformity), which is an important element of the image, is not sufficient.

Further, in a conventional projection display device using a discharge lamp such as a halogen lamp, if the voltage application axis is not orthogonal to the optical axis of the projection lens, the lighting posture of the discharge lamp changes, A change in hue and illuminance occurs with a change in the projection direction.

Therefore, an object of the present invention is to provide a projection display device having good hue and color reproducibility and stable illuminance.

[Means for solving the problem]

The projection type liquid crystal display device of the present invention includes a light source unit including a discharge lamp that emits light by applying a voltage between a pair of electrodes, a modulating unit that modulates light from the light source unit, and a modulating unit. A projection type liquid crystal display device comprising: projection optical means for projecting modulated light, wherein the angle of the optical axis of the projection optical means with respect to the installation surface of the projection type liquid crystal display device can be changed. It has a direction changing means, a voltage application axis to a pair of electrodes of the discharge lamp,
The discharge lamp is perpendicular to the optical axis of the projection optical unit, and the discharge lamp is always kept in a horizontal lighting state regardless of the change in the angle by the projection direction changing unit.

[Action]

According to the above configuration of the present invention, the state of arc discharge, that is, the direction of the voltage application axis is always horizontal to the mounting position of the projection display device (horizontal lighting state), so that the discharge state of the lamp is reduced. Become stable. For example, a metal halide lamp is filled with a complex compound such as Sn, In, Tl, Ag, Na, and I in a tube, but the temperature at which each metal atom evaporates varies, and a horizontal lighting state may be maintained. This leads to stabilization of the tint of the image projected by the projection display device.

〔Example〕

Embodiment 1. Embodiment 1 describes in detail the structure of a lamp with a reflector of a lamp used in a projection type liquid crystal display device of the present invention.

FIG. 1 is a sectional view showing a section of a lamp with a reflector, and a discharge lamp 30 is a metal halide lamp filled with a composite compound. The electrode 31 is an electrode formed of tungsten, and a molybdenum thin film 32 is thermocompression-bonded. The reflector 33 is adhered and fixed to the discharge lamp 30 by ceramic cement.

The reflector 33 is a parabolic or elliptical reflector, and the light-emitting point of the tungsten electrode 31 divided into two equal parts is matched to the optical focal position.

FIG. 2 is a partial detailed view showing a state of discharge of the discharge lamp shown in FIG.

The state of the discharge is such that the spectrum peculiar to the metal when dissociating into mercury Ag or other halogen compound metal atoms or haloben atoms inside the lamp has a discharge arc 20 that is relatively centered between the electrodes, There is a discharge arc 21.

In these discharge lamps, all conditions such as color change, deterioration in uniformity of illuminance, and discharge stability are dominantly sensitive to the lighting posture of the lamp (direction of the voltage application axis of the discharge lamp). . This is because changing the lighting attitude changes the temperature distribution inside the lamp, which changes the discharge state. That is, it is important for the discharge lamp to maintain a constant lighting posture.

Embodiment 2 Embodiment 2 describes in detail the structure of the projection type liquid crystal display device of the present invention.

FIG. 3 is a plan view of a projection type liquid crystal display device using three transmission type liquid crystal light valves.

The lamp 10 is a discharge lamp having the content described in the first embodiment. White light emitted from the lamp 10 is incident on a liquid crystal light valve 15 via a mirror 14 by a red reflecting dichroic mirror 11 via a red light. Red reflective dichroic mirror
The color light transmitted through 11 is reflected by the green reflecting dichroic mirror 12 and enters the liquid crystal light valve 15. Further, the color light transmitted through the green reflecting dichroic mirror 12, that is, the blue light is reflected twice by the reflecting mirror 14, and the liquid crystal light valve 15
Incident on. The liquid crystal light valve 15 that has entered each color light,
The amount of transmitted light is controlled by electric signals of television images and computer graphics images. These modulated color lights are combined by the cube prism 16 having two-color reflection characteristics, and the color lights are combined, and the projection lens 13 forms an image on a screen by projection.

In this embodiment, the direction of the voltage application axis of the lamp 10 and the optical axis of the projection lens 13 are arranged at positions orthogonal to each other.

FIG. 4 is a plan view showing the configuration of another embodiment of the projection type liquid crystal display device of the present invention.

White light emitted from the lamp 10 is 90 ° by the mirror 14.
And the light enters the X-shaped dichroic mirror 17. The incident white light has three primary colors R in the remaining three directions.
G and B, and the liquid crystal light valve 15
Guide colored light to Thereafter, an image is formed on the screen in the same manner as in FIG.

In this embodiment, as in FIG. 3, the direction of the voltage application axis of the lamp 10 and the optical axis of the projection lens 13 are arranged at positions orthogonal to each other.

Third Embodiment In a third embodiment, the projection display device of the present invention will be described in detail with reference to schematic diagrams in a state where it is assumed that the projection display device is actually used from various angles.

FIG. 5 is a schematic diagram showing two states (a) and (b) of the actual use state of the projection type liquid crystal display device.

(A) A state in which the projection type liquid crystal display device is suspended from the ceiling.

(B) A state in which the projection type liquid crystal display device is projected on a screen on the floor.

The above two states indicate that the projection-type liquid crystal display device is portable, so that the projection direction changing means 35 can be installed with a high degree of freedom in actual use.

Here, as shown in FIG. 5 (a), when the projection type liquid crystal display device main body 1 is hung on the ceiling, the angle of the projection lens with respect to the installation surface of the optical axis, that is, the elevation angle θ is determined by the observer. Must be at an angle that does not shadow the screen 2. As shown in FIG. 5 (b), when the projection type liquid crystal display device main body 1 is placed on the floor and projection is performed on the screen 2, the direction of elevation θ is opposite to that when the projector 1 is suspended from the ceiling. Requires an elevation angle θ.

However, by using a projection-type liquid crystal display device as shown in FIGS. 3 and 4, no matter what the projection direction, the projection direction changing means can be used.
According to 35, even if the angle of the optical axis of the projection lens with respect to the installation surface is changed, the optical axis of the projection lens and the voltage application axis of the discharge lamp are always orthogonal. Therefore, the discharge lamp is always kept in the horizontal lighting state.

〔The invention's effect〕

As described above, according to the projection type liquid crystal display device of the present invention, the discharge lamp is always in the horizontal lighting state regardless of the change in the angle of the optical axis of the projection optical unit with respect to the installation surface of the projection type liquid crystal display device. As a result, it is possible to obtain an image with stable color tone and illuminance and excellent color reproducibility.

[Brief description of the drawings]

FIG. 1 is a sectional view relating to the structure of a discharge lamp. FIG. 2 is a partial detailed view showing a state of discharge of a discharge lamp. FIG. 3 is a plan layout view of the projection type liquid crystal display device according to the embodiment of the present invention. FIG. 4 is a plan layout view showing another configuration of the projection type liquid crystal display device according to the embodiment of the present invention. 5 (a) and 5 (b) are schematic diagrams showing an actual use state of the projection display device of the present invention. 30 Discharge lamp 33 Reflector 20 Discharge arc 15 Liquid crystal light valve 35 Projection direction changing means 23 Center between electrodes

Claims (1)

(57) [Claims] A light source unit having a discharge lamp that emits light by applying a voltage between a pair of electrodes; a modulation unit that modulates light from the light source unit; and a light unit that modulates the light modulated by the modulation unit. A projection type liquid crystal display device comprising: a projection optical unit for projecting; and a projection direction changing unit capable of changing an angle of an optical axis of the projection optical unit with respect to an installation surface of the projection type liquid crystal display device. The voltage application axis to the pair of electrodes of the discharge lamp is orthogonal to the optical axis of the projection optical unit, and the discharge lamp is irrespective of the change in the angle by the projection direction changing unit. A projection type liquid crystal display device which is always kept in a horizontal lighting state.