JPS62257126A - Liquid crystal display plate for projection device - Google Patents

Abstract

PURPOSE:To omit an independent reflecting plate by providing substrates where electrodes are formed to the front and rear surfaces of liquid crystal, and using a transparent electrode as the electrode on the front surface side and forming a reflecting surface on the substrate on the rear surface side. CONSTITUTION:When a light beam from a light source 11 is projected on a liquid crystal display plate 9 and electrodes 4 and 5 are selected and applied with a voltage, dots are formed on liquid crystal to display an image. At this time, a condenser lens 12 diverges the illumination light from the light source 11 almost to the contour of the liquid crystal display plate 9. This illumination light is converged by the converging Fresnel lens 7 without any waste and projected on the liquid crystal 1, and the light is reflected by the electrode 5 and transmitted through the liquid crystal 1 again; and the light is converged by the converging Fresnel lens 7 to illuminate almost to the overall diameter of an image forming lens 13, and then projected on a screen 7. The electrode 5 contacts the rear surface of the liquid crystal 1, so a reflected image never shifts in position and the electrode 5 is utilized as the reflecting surface, so the reflecting plate need not be provided independently and have its installation position adjusted.

Description

[Detailed description of the invention] Industrial applications The second invention relates to a liquid crystal display panel for a projection device.

2. Description of the Related Art Conventionally, for example, as described in Japanese Patent Laid-Open No. 59-19924, a light beam is transmitted through a liquid crystal display panel.

There is a transmission type projection device that projects an image on a liquid crystal display panel onto a screen. In addition to this, there is a reflection type projection device that applies illumination light to a liquid crystal display plate, reflects the illumination light that has passed through the liquid crystal display plate, and projects an image onto a screen by transmitting the illumination light through the liquid crystal display plate again.

Problems to be Solved by the Invention However, the above projection apparatus requires an independently manufactured reflector plate to be installed in the optical path. Its installation requires position adjustment, which complicates assembly work and structure.

The present invention has been made in view of these points, and provides a liquid crystal display for a projection device that omits an independent reflector plate, simplifies assembly work and structure, and can form a clear image with high contrast. The purpose is to provide a board.

Means for solving the gap point A substrate on which electrodes are formed on the front and back sides of the liquid crystal is provided, and the substrate on the front side is made a transparent substrate, the electrode on the front side is made a transparent electrode, and the substrate on the back side is made a transparent substrate. form a reflective surface.

Function: Therefore, the illumination light emitted from the front is transmitted through the liquid crystal, reflected by the reflective surface, and transmitted through the liquid crystal again to be projected.
By forming the reflective surface on the back substrate, an independent reflective plate is omitted.

Furthermore, since the illumination light passes through the liquid crystal twice, it is possible to form a clear image with high contrast.

Embodiment A first embodiment of the present invention will be described with reference to FIGS. 1 to 3. Transparent substrates 2 and 3 are bonded to the front and back surfaces of a liquid crystal 1 on a rectangular plate.

A large number of band-shaped transparent electrodes 4 are formed in parallel on the back surface of the front transparent substrate 2, and a large number of band-shaped electrodes 5 are formed in parallel in a direction perpendicular to the transparent electrodes 4 on the front surface of the back transparent substrate 3. ing. These electrodes 5 are formed of metal foil such as aluminum and serve also as a reflective surface. Further, on the front surface of the front transparent substrate 2, a transmission type condensing Fresnel lens 7, which has a large number of annular grooves 6 arranged concentrically, is integrally formed. The distance between the transparent substrates 2 and 3 is determined by a rectangular spacer 8 surrounding the liquid crystal 1.

The liquid crystal display panel 9 configured in this manner is housed in the back of the housing 10 as shown in FIG. is held in the housing 10. A screen 14 is provided in front of the housing 1o.

In such a configuration, when the light beam of the light source 11 is applied to the liquid crystal display plate 9 and a voltage is applied to selected electrodes 4 and 5, dots are formed on the liquid crystal 1 and an image is displayed. At this time, the condenser lens 12 diffuses the illumination light from the light source 11 to an extent that exactly matches the outline of the liquid crystal display panel 9. This illumination light is condensed by the condensing Fresnel lens 7 without wasting it, and the illumination light is The light is reflected by the electrode 5, passes through the liquid crystal 1 again, is focused by the condensing Fresnel lens 7 so as to illuminate the entire aperture of the imaging lens 13, and is projected onto the screen 14.

In this way, an image is projected. The condensing Fresnel lens 7 condenses the illumination light from the light source 11 just in front of the liquid crystal 1, irradiates the entire surface of the liquid crystal 1, and forms the light rays reflected by the electrodes 5 into an image. It becomes possible to condense the light so that it irradiates the entire aperture of the lens 13, and the electrode 5 serving as a reflective surface efficiently reflects the illumination light. Furthermore, since the electrode 5 is in close contact with the back surface of the liquid crystal 1, the reflected image will not shift. Therefore, even if a liquid crystal 1 with a large area and a large number of small dots is used, the resolution of the projected image can be improved. Moreover, since the illumination light passes through the liquid crystal 1 twice, the contrast of the image can be increased and the outline can be made clear. Furthermore, by using the electrode 5 as a reflective surface, there is no need to separately provide a reflective plate and adjust its installation position, and the condensing Fresnel lens 7 is also formed integrally with the transparent substrate 2, so it does not need to be provided separately. There is no need to adjust the mounting position. Further, the condensing Fresnel lens 7 is located just in front of the liquid crystal 1, and by arranging the light source 11 and the imaging lens 13 in front of it, the optical path length can be shortened and space can be saved.

Note that since the electrode 5 does not transmit light, an opaque substrate may be used in place of the transparent substrate 3 on the back surface.

Next, a second embodiment of the present invention will be described based on FIG. 4. The same parts as those in the above embodiment will be designated by the same reference numerals, and the description thereof will be omitted (the same applies hereinafter). In this embodiment, a reflective surface 15 made of metal foil is formed on the entire back surface of a transparent substrate 3, and a transparent electrode 16 is formed on the front surface of the transparent substrate 3.

Therefore, the reflective surface 1 formed on the entire back surface of the transparent substrate 3
By reflecting the illumination light by the electrodes 5, the reflection efficiency can be further improved compared to the case where the electrodes 5 arranged with even a slight gap are used as the reflection surface as in the above embodiment.

As a modification, the back surface of the reflective surface 15 may be covered with a protective layer 17 as shown in FIG.

This protective layer 17 is formed, for example, from the same material as the transparent substrate 3 by means such as double molding.

Furthermore, a third embodiment of the present invention will be described based on FIG. 6. In this embodiment, a reflective Fresnel lens 19, which is a reflective surface, is formed by forming a plurality of grooves on the back surface of a transparent substrate 3 and forming a metal film 18 thereon.
The surface of this reflective Fresnel lens 19 is covered with a protective layer 20. This protective layer 20 is, for example, formed by double molding the same material as the transparent substrate 3.

This protective layer 20 can also be omitted.

Therefore, the reflective Fresnel lens 19 reflects the illumination light from the light source 11 and focuses the reflected light so that it irradiates the entire aperture of the imaging lens 13 . In this way, one member can reflect and collect light at the same time, so
The structure can be further simplified.

Next, we will show an embodiment that does not include a condensing Fresnel lens but does include a reflective surface.

FIG. 7 shows a fourth embodiment of the invention, in which the liquid crystal 1
A transparent substrate 2 having a transparent electrode 4 is disposed on the front surface of the liquid crystal 1, and a transparent substrate 3 on which an electrode 5 made of metal foil having the function of a reflective surface is formed is disposed on the back surface of the liquid crystal 1. That is, in the liquid crystal display panel 19 shown in FIGS. 1 and 2, the formation of the condensing Fresnel lens 7 is omitted, and the reflective function of the electrode 5 is retained.

FIG. 8 shows a fifth embodiment of the present invention, in which the formation of the condensing Fresnel lens 7 is omitted in the liquid crystal display panel 9 shown in FIG. 4, and the reflective function of the reflective surface 15 is retained. be.

FIG. 9 shows a sixth embodiment of the present invention, in which the formation of the condensing Fresnel lens 7 is omitted in the liquid crystal display panel 9 shown in FIG. 5, and the reflective effect of the reflective surface 15 is retained. be.

Since the devices shown in FIGS. 7, 8, and 9 all have the function of reflecting the illumination light from the light source 11, there is no need to separately provide an independent reflecting plate whose mounting position needs to be adjusted.

Effects of the Invention Since the present invention is constructed as described above, illumination light emitted from the front is transmitted through the liquid crystal, reflected by the reflective surface, and transmitted through the liquid crystal again for projection.However, the reflective surface is formed on the back substrate. By doing so, it is possible to omit an independent reflection plate that requires adjustment of the mounting position, and therefore, the assembly work and structure can be simplified.Furthermore, the reflection surface can be moved close to the back of the liquid crystal to reflect light. It is possible to prevent image shift, and furthermore, since the illumination light passes through the liquid crystal twice, it has effects such as being able to form a clear image with high contrast.

[Brief explanation of drawings]

1 to 3 show a first embodiment of the present invention, in which FIG. 1 is a longitudinal side view, FIG. 2 is a plan view, and FIG. 3 is a longitudinal side view showing a reduced image projection state. FIG. 4 is a longitudinal side view showing a second embodiment of the invention, FIG. 5 is a longitudinal side view showing a modification thereof, and FIG. 6 is a longitudinal side view showing a third embodiment of the invention. , FIG. 7 is a longitudinal side view showing a fourth embodiment of the invention, FIG. 8 is a longitudinal side view showing a fifth embodiment of the invention, and FIG. 9 is a longitudinal side view showing a sixth embodiment of the invention. FIG. 1...Liquid crystal, 2, 3...Transparent substrate (substrate), 4...
・Transparent electrode, 5... Electrode (reflective surface), 15... Reflective surface, 16... Transparent electrode, 19... Reflective Fresnel lens (reflective surface) Part 3, IZ J34" R J35 diagram , %61 Figure Procedure Correction Band (Ki) March 11, 1986

Claims (1)

[Claims] It is characterized by providing substrates on which electrodes are formed on the front and back sides of the liquid crystal, the substrate on the front side being a transparent substrate, the electrodes on the front side being transparent electrodes, and the substrate on the back side forming a reflective surface. A liquid crystal display panel for a projection device.