JPH0552844U - LCD projector - Google Patents

Abstract

(57) [Abstract] [Purpose] It is possible to miniaturize a dichroic prism of a combination system of R, G, and B image lights of a liquid crystal projector. [Structure] Three liquid crystal panels 40, 42, and 44 for R, G, and B arranged in a substantially U shape are illuminated by R, G, and B lights, and R, G, which have passed through each liquid crystal panel, In a liquid crystal projector that combines the B image with a dichroic prism 46 arranged in the central portion of the three liquid crystal panels 40, 42, and 44, and projects the color image combined with the dichroic prism 46 through a projection lens, Three lenses 50, 5 for converging light respectively between the three liquid crystal panels 40, 42, 44 and the dichroic prism 46.
2, 54 are provided so that the liquid crystal panels 40, 4
The dichroic prism 46 whose incident surface is smaller than the panel surfaces of 2, 44, that is, the dichroic prism 46 that is miniaturized can be applied.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 The present invention relates to a liquid crystal projector, and more particularly, to a liquid crystal projector which synthesizes R, G, B images through three liquid crystal panels for R, G, B to obtain a color image.

[0002]

[Prior Art]

 As a conventional liquid crystal projector of this type, there is a liquid crystal projector as shown in FIG. 2 (Japanese Patent Publication No. 3-103842). As shown in the figure, white light emitted from one light source (for example, a metal halide lamp) 10 is incident on a dichroic mirror 14 via a heat ray cut filter 12.

The dichroic mirror 14 reflects only blue (B) light of incident light and transmits red (R) and green (G) light. The B light reflected by the dichroic mirror 14 enters the B liquid crystal panel 24 via the reflection mirror 18. On the other hand, the R and G lights transmitted through the dichroic mirror 14 are incident on the dichroic mirror 16, where the G light is reflected and enters the liquid crystal panel 26 for G, and the R light is transmitted and reflected on the reflection mirror 20. The light enters the liquid crystal panel 28 for R through 22.

The R, G, and B images displayed by each liquid crystal panel are illuminated by the R, G, and B lights that have been color-divided, and the transmitted light of each liquid crystal panel is combined by the dichroic prism 30. And is projected as a color image through the projection lens 32. The dichroic prism 30 is formed by adhering four right-angle prisms, and an R light reflection film 30A and a B light reflection film 30B are vapor-deposited on the adhesion surface so as to be orthogonal to each other.

[0005]

By the way, the dichroic prism 30 is required to have the same incident surface as the panel surface of each liquid crystal panel. Therefore, the conventional liquid crystal projector requires a large dichroic prism. Inviting higher costs. The present invention has been made in view of such circumstances, and an object thereof is to provide a liquid crystal projector that enables downsizing of a dichroic prism and cost reduction.

[0006]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention illuminates three liquid crystal panels for R, G, and B arranged in a substantially U shape with R, G, and B lights, and transmits R through each liquid crystal panel. , G, B images are combined by a dichroic prism arranged at the center of three liquid crystal panels, and a color image combined by the dichroic prism is projected through a projection lens. Is characterized in that three lenses for converging light are arranged between the liquid crystal panel and the dichroic prism, and a dichroic prism having an incident surface smaller than the panel surface of the liquid crystal panel is used.

[0007]

[Action]

 According to the present invention, between the three liquid crystal panels and the dichroic prism, three lenses for respectively converging the R, G, and B image lights are arranged. Therefore, it becomes possible to use a dichroic prism whose incident surface is smaller than the panel surface of the liquid crystal panel, and thereby the size of the dichroic prism is reduced.

[0008]

【Example】

 Hereinafter, preferred embodiments of a liquid crystal projector according to the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a plan view of an essential part showing an embodiment of a liquid crystal projector according to the present invention, and an illumination system for illuminating each liquid crystal panel is omitted.

In the figure, reference numerals 40, 42 and 44 are liquid crystal panels for R, G and B illuminated by R, G and B lights, respectively, 46 is a dichroic prism, 48 is a projection lens main body, 50, 52 and 54. Are convex lenses. The projection lens is composed of a projection lens main body 48 and convex lenses 50, 52 and 54, and is designed so that there is a space into which the dichroic prism 46 can be placed at a position where the R, G and B image lights are narrowed down. That is, the convex lenses 50, 52, 54 are arranged between the R, G, B liquid crystal panels 40, 42, 44 and the dichroic prism 46, respectively.

Therefore, the R, G and B image lights transmitted through the R, G and B liquid crystal panels 40, 42 and 44 are converged by the convex lenses 50, 52 and 54 and enter the dichroic prism 46. As a result, the dichroic prism 46 having an incident surface smaller than the panel surface of each liquid crystal panel can be used. The dichroic prism 46 is formed by adhering four right-angle prisms, and an R light reflection film 46A and a B light reflection film 46B are formed on the adhesion surface so as to be orthogonal to each other. Therefore, by providing the convex lenses 50, 52, and 54, a small rectangular prism can be used, and the bonding surface of each right-angled prism is also reduced, so that the manufacturing cost of the dichroic prism 46 can be significantly reduced. ..

The R, G, and B image lights incident on the dichroic prism 46 from the liquid crystal panels 40, 42, and 44 via the convex lenses 50, 52, and 54 are combined by the dichroic prism 46 and projected as a color image. It is projected through the lens body 48.

[0012]

[Effect of the device]

 As described above, according to the liquid crystal projector of the present invention, the three lenses for converging the R, G, and B image lights are arranged between the three liquid crystal panels and the dichroic prism. The size of the dichroic prism can be reduced, and the manufacturing cost of the dichroic prism can be reduced.

[Brief description of drawings]

FIG. 1 is a plan view of essential parts showing an embodiment of a liquid crystal projector according to the present invention.

FIG. 2 is a plan view showing an example of a conventional liquid crystal projector.

[Explanation of symbols]

 40, 42, 44 ... Liquid crystal panel 46 ... Dichroic prism 48 ... Projection lens body 50, 52, 54 ... Convex lens

Claims (1)

[Scope of utility model registration request] 1. A R-, G-, and B-shaped 3 arranged in a substantially U-shape
The liquid crystal panels are illuminated with R, G, and B lights, and the R, G, and B images transmitted through the respective liquid crystal panels are combined by a dichroic prism arranged in the central portion of the three liquid crystal panels,
In a liquid crystal projector for projecting a color image combined by the dichroic prism through a projection lens, three sets of lens groups for converging light are respectively arranged between the three liquid crystal panels and the dichroic prism. A liquid crystal projector using a dichroic prism having an incident surface smaller than the panel surface of the liquid crystal panel.