JP3397833B2 - LCD projector - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal projector, and more particularly to a single-panel type liquid crystal projector.

[0002]

2. Description of the Related Art A conventional liquid crystal projector of this type is shown in FIG.

In FIG. 2, reference numeral 1 is a light source composed of a metal halide lamp or the like, and 2 is a circular parabolic mirror for reflecting the light from the light source 1 into uniform parallel light.
Reference numeral 4 is a condenser lens for condensing the light flux created by the parabolic mirror on the liquid crystal panel. Reference numeral 5 denotes a liquid crystal display unit 9 that optically modulates the light passing through the condenser lens 4 by a signal from a video signal processing circuit (not shown), and a drive unit 8 in which a driver and the like for making full use of the liquid crystal display unit 9 are arranged. It is a liquid crystal panel consisting of. A projection lens 6 enlarges and displays an image optically modulated by the liquid crystal panel 5 on the screen 7.

In the conventional liquid crystal projector, the light emitted from the light source 1 is reflected by the parabolic mirror 2, and as a result, the light having a circular cross section is applied to the condenser lens 4. Here, the reflected light from the parabolic mirror 2 is condensed by the condenser lens 4, and the liquid crystal panel 5
To the liquid crystal display unit 9 of the liquid crystal panel 5.
Since the shape is rectangular, as shown in FIGS. 3 and 4, light is also applied to the shaded areas other than the liquid crystal display section 9, and the amount of light projected onto the screen 7 by the liquid crystal panel 5 is reduced. That is, the light flux A is transmitted to the liquid crystal display unit 9 of the liquid crystal panel 5.
The light beams B and C pass through the drive unit 8 of the liquid crystal panel 5.
Will be blocked by.

Here, FIG. 3 is a diagram showing a decrease in the amount of light when the liquid crystal display section 9 is configured to have a wide aspect ratio (16: 9), and FIG. 4 shows the liquid crystal display section 9 in a normal aspect ratio. It is a figure which shows the reduction of the light quantity at the time of comprising in (4: 3).

That is, in the case of the liquid crystal display unit having the shape shown in FIG. 3, the amount of light from the condenser lens 4 is about 46%.
In the case of the liquid crystal display unit having the shape shown in FIG. 4, the light amount is reduced by about 39%.
The image displayed in magnified was dark.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks, and an object thereof is to transmit light through a liquid crystal display section of a liquid crystal panel without impairing the amount of light from a light source with a simple structure. To do.

[0008]

SUMMARY OF THE INVENTION The present invention is directed to a light source including a metal halide lamp, a condenser lens for condensing light from the light source, a liquid crystal display section for optically modulating light passing through the condenser lens, and a liquid crystal. In a liquid crystal projector comprising a liquid crystal panel having a drive section for driving the liquid crystal display panel and a projection lens for enlarging and displaying the light optically modulated by the liquid crystal panel, a liquid crystal display section formed by a light converging member. In the liquid crystal projector, a condenser lens having an opening corresponding to is disposed between the light source and the liquid crystal panel.

Further, the present invention is a liquid crystal projector in which the light converging member is a Fresnel lens.

Further, the present invention is the liquid crystal projector, wherein the aperture formed in the condenser lens has a rectangular shape with an aspect ratio of 16: 9 or 4: 3.

[0011]

According to the present invention, the light flux A from the light source and the parabolic mirror passes through the opening of the condenser lens and is applied to the liquid crystal display portion of the liquid crystal panel. . On the other hand, among the light fluxes from the light source and the parabolic mirror, the light fluxes B and C are converged by the Fresnel lens of the condenser lens, and the converged light flux is applied to the liquid crystal display unit of the liquid crystal panel.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention increases the light utilization rate of the light source 1 by taking in the wasted light radiated to the drive section 8 of the liquid crystal panel 5 into the liquid crystal display section 9 of the liquid crystal panel 5, thereby increasing the brightness of the liquid crystal. Characterized by obtaining a projector.

An embodiment of the present invention will be described below with reference to the drawings.

Here, FIG. 1 is an optical block diagram of the liquid crystal projector of the present invention, FIG. 5 is a front view showing the mounting state of the condenser lens 10, FIG. 6 is a sectional view taken along line XX of FIG. 5, and FIG.
FIG.

The same parts as those in FIG. 2 are designated by the same reference numerals,
The description is omitted.

A feature of the present invention is that a condenser lens 10 is integrally provided on the output side of the cold filter 3 as shown in FIG.

The condenser lens 10 is formed of resin, and has a rectangular opening 10b which matches the aspect ratio of the liquid crystal display 9 of the liquid crystal panel 5, as shown in FIG.
A Fresnel lens 10c is formed on the outside of the Fresnel lens. The outermost circle of the Fresnel lens 10c is formed to be substantially equal to or slightly larger than the outer shape of the cold filter 3.

Therefore, of the light from the light source 1, the light flux A that has passed through the opening 10b directly passes through the liquid crystal display portion 9 of the liquid crystal panel 5. Also, of the light from the light source 1,
Light flux B and light flux C that have passed through the Fresnel lens 10c
Will pass through the liquid crystal display unit 9 of the liquid crystal panel 5 after being converged.

That is, the irradiation light emitted from the light source 1 is
Most of the light passes through the liquid crystal display unit 9 of the liquid crystal panel 5.

The condenser lens 10 is the Fresnel lens 1
Instead of 0c, a plano-convex lens or the like that collects light can be used instead.

Next, the mounting of the condenser lens 10 will be described.

Now, the light source 1 is attached integrally with the parabolic mirror 2 by the lamp bracket 13, and the cold filter 3 and the condenser lens 10 are attached by the screw 11 to the filter bracket 12.

Here, the lamp bracket 13 and the filter bracket 12 are positionally fixed at an interval T that is not affected by heat from the light source 1. The lamp bracket 13 and the filter bracket 12 are positioned by a mounting base (not shown).

Therefore, the light source 1 and the condenser lens 10 are accurately fixed.

Next, the attachment of the condenser lens 10 and the cold filter 3 to the filter bracket 12 will be described in detail.

First, the cold filter 3 is housed in the concave portion of the filter bracket 12, and the rectangular condenser lens 10 is placed on the cold filter 3 and then fixed by the four screws 11. Therefore, the cold filter 3 is fixed between the filter bracket 12 and the condenser lens 10. At this time, the outer shape of the condenser lens 10 is changed to the filter bracket 12
Is slightly larger than the outer shape of the condensing lens 10 and the elongated holes 10a are provided at the four corners of the condensing lens 10, so that the condensing lens 10 is elastically fixed to the filter bracket 12.

In this embodiment, the condenser lens 10 is placed in close contact with the cold filter 3, but the condenser lens 1
0 may be arranged separately from the cold filter 3.

[0028]

Since the present invention is configured as described above, since the light flux that has been conventionally blocked by the liquid crystal panel can be guided into the liquid crystal display section by the condenser lens, the image displayed on the screen can be changed. The illuminance can be improved. Further, even if a light source having a low illuminance other than the metal halide lamp is used, an image having the same illuminance as the conventional one can be obtained on the screen.

[Brief description of drawings]

FIG. 1 is a diagram showing a liquid crystal projector of the present invention.

FIG. 2 is a diagram showing a conventional liquid crystal projector.

FIG. 3 is a diagram showing a decrease in light amount when a liquid crystal display unit is configured to have a normal aspect ratio (4: 3).

FIG. 4 shows a liquid crystal display unit with a wide aspect ratio (16: 9).
It is a figure which shows the reduction of the light quantity in the case of being comprised.

FIG. 5 is a front view showing a mounting state of a condenser lens.

6 is a sectional view taken along line XX of FIG.

7 is a sectional view taken along line ZZ of FIG.

[Explanation of symbols]

1 light source 2 parabolic mirror 4 condenser lens 5 LCD panel 6 Projection lens 9 LCD display 10 Condensing lens 10a long hole 10b opening 10c Fresnel lens

Claims (2)

(57) [Claims] 1. A light source comprising a metal halide lamp or the like, a condenser lens for condensing light from the light source, a liquid crystal display section for optically modulating the light passing through the condenser lens, and a drive section for driving the liquid crystal. In a liquid crystal projector comprising a liquid crystal panel and a projection lens for magnifying and displaying the light optically modulated by the liquid crystal panel, a condensing lens formed by a Fresnel lens and having an opening corresponding to the liquid crystal display section. Is disposed between the light source and the liquid crystal panel. 2. The liquid crystal projector according to claim 1, wherein the aperture formed in the condenser lens has a rectangular shape with an aspect ratio of 16: 9 or 4: 3.