JPS5810720A - Electrooptical device - Google Patents

Abstract

PURPOSE:To obtain a liquid crystal light valve which is provided with a sufficient function with a simple sturcture, by interposing a light shielding layer, which has plural transmission holes corresponding to picture elements, and plural reflective mirrors, which face to respective transmission holes through a light-transmittable insulating layer and are separated from one another, between a liquid crystal layer and a photoconductive layer. CONSTITUTION:When a voltage is applied across transparent electrodes 2a and 2b and a signal ray is projected to a photoconductive layer 9 through a transparent substrate 1b, the resistance of the photoconductive layer 9 in this projection part is reduced, and the value of the voltage applied to the corresponding part of a liquid crystal layer 3 is increased through a transmission hole 6, and the orientation direction of the liquid crystal existing in the corresponding area is changed. A projected image is formed in the liquid crystal layer 3, and the projection light is projected from the side of a transparent substrate 1a and is reflected by a mirror 8, thereby magnifying and projecting the image generated in the liquid crystal layer 3 onto a screen or the like. Troubles of the leakage of the signal ray to the side of the crystal layer 3 and the incidence of the pro- jection light to the photoconductive layer 9 are prevented by a light shielding layer 5 and mirrors 8.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electro-optical device that converts an optical input image into a projected image using the photoelectric effect.

Conventionally, this type of electro-optical device was liquid crystal lysivalp (
The light valve) is known.

As an example, JP-A-56-43681 discloses a thin film multilayer structure consisting of a liquid crystal layer, a dielectric mirror, and a photoelectric sensitive layer (photoconductive layer) sandwiched between two transparent electrodes. A liquid crystal light pulp that takes In such a liquid crystal light pulp, the dielectric mirror is a necessary element for reflecting the projection light incident from the liquid crystal layer side in advance so that it does not reach the photoconductive layer.

ing. At this time, in order to obtain a dielectric mirror that reflects wavelengths throughout the visible range, it is necessary to create a laminate of approximately 15 or more layers while precisely controlling the thickness of each layer, which requires considerably advanced manufacturing technology. It takes. Furthermore, even if a dielectric mirror is made for the above purpose, in reality it cannot completely reflect the projected light, and a separate light absorption layer is required between the photoconductive layer and the dielectric mirror. It was necessary to establish a system and supplement its functions.

Therefore, such conventional liquid crystal light pulp does not fully exhibit its intended function, has a complicated structure, and requires time and effort to manufacture, resulting in high manufacturing costs.

Therefore, the present invention eliminates the various drawbacks of the conventional liquid crystal display, which is generally a liquid crystal light source, which has a simple structure and sufficient functions.
The purpose of this invention is to provide an electro-optical device called a bulb.

Another object of the present invention is to provide an electro-optical device that enables high-resolution color display.

To achieve these objects, the present invention is an electro-optical device that includes a liquid crystal layer and a photoconductive layer, converts an input image of light into a projected image by photoelectric effect, and has a plurality of through holes corresponding to pixels. A plurality of reflective mirrors facing each of the through holes and separated from each other are provided between the liquid crystal layer and the photoconductive layer through a light shielding layer and a light transmitting insulating layer in contact with one side of the light shielding layer. It is characterized by being formed by intervening.

Hereinafter, the present invention will be explained by way of examples using drawings.

FIG. 1 is a schematic cross-sectional view of the first embodiment. In FIG. 1, both 1aqlb and 1aqlb are transparent substrates made of a glass plate or a resin plate. Also, both 2m and 2b are transparent electrodes, for example 81
It consists of a thin film such as In* (8m) OR. 3
4 is a liquid crystal layer, and 4 is a spacer for sealing the liquid crystal layer 3 and adjusting its layer thickness. As the spacer 4, a resin adhesive mixed with alumina powder or glass 7'''M bar powder is usually used.

5 is a light-shielding layer, which is formed by depositing carbon or metal to a thickness of about 500^-2 μm. This light-shielding layer 5 has a planar shape as shown in FIG.
A large number of through holes 6 are arranged in the hole. Note that one of the through holes 6 corresponds to one pixel in the projected image. Incidentally, the shape of these through holes 6 is not limited to the square shown in the illustrated example, but can be any shape.

Furthermore, 7 in FIG. 1 is a light-transmitting insulating layer, for example, an 810.811N4 film formed by discharge decomposition, a stag film or Pb? film formed by sputter deposition, etc. %Q
It consists of a ferroelectric film such as PLZT. The thickness of the light-transmitting insulating layer 7 is preferably in the range of 1000 μm.

8 is a reflective mirror, and the thickness of metal such as a forming the mirror surface is 50
It consists of a deposited film with a thickness of about 0 μm to 1 μm. A large number of mirrors 8 are arranged so as to face all of the through holes 6, and each mirror 8 is arranged as shown in FIG. 3, which is a cutaway plan view of the BSBJ of FIG. 1. Incidentally, one of these mirrors 8 is
In order to prevent light from leaking between the mirrors @sn, it is formed to have an area (width) that is at least larger than the area of the through hole 6.

Reference numeral 9 denotes a photoconductive layer, which is generally made of a well-known photoconductive material whose dark resistance is higher than the resistance of the liquid crystal layer 3, as will be described later. Examples of photoconductive materials include 8-based lucogen substances such as 8., a@-T@, Muhata*@@s, 0(15,
Examples include Group 2-6 compounds such as O and Zn5, inorganic materials such as amorphous silicon, and organic photoconductive materials typified by polyvinyl carbazole.

Here, the operation of the optical sending type liquid crystal light valve shown in FIG. 1 will be briefly explained.

When a signal beam is projected onto the photoconductive layer 9 through the transparent substrate 1k with a predetermined voltage applied between the transparent electrodes 2a and 2b from a power supply (not shown), the photoconductive layer 9 at that location is
resistance decreases. Then, the positive t value applied to the liquid crystal layer 3 corresponding to the region onto which the signal beam is projected increases through the through hole 6, and the alignment direction of the liquid crystal in the corresponding region changes.

In this way, a projection image (an image for projection) is formed in the liquid crystal layer 3 based on the difference in the alignment direction of the liquid crystal, and projection light is projected onto this from the transparent substrate 1a side. By reflecting the projection light by the mirror 8, the image generated in the liquid crystal layer 3 is enlarged and projected onto a screen (not shown) or the like.

In the above process, the light shielding layer 5 and the mirror 8
This prevents the signal light from leaking into the liquid crystal layer 311 and the projection light from entering the photoconductive layer 9.

In the above operation example, unless the projected image formed in the liquid crystal layer 3 is extremely fine, the projected image can be visually observed under indoor light without using special projection light. You can also do that.

By the way, in the embodiment shown in FIG. 1, a light absorbing member such as a carbon layer is provided on the surface of the light shielding layer 5 on the side of the light transmitting insulating layer 7, so that the reflected return light due to the projection light is absorbed. It absorbs
This is desirable in order to increase the contrast of the projected image.

Further, the reflecting mirror 8 must be made entirely of a conductive material and must be separated, but its shape does not matter.

The reason why all of the reflecting mirrors 8 are separated is because if they are continuous, they will have the same potential and no potential difference will occur.
This is because image formation becomes impossible.

When forming a projected image, the dark resistance of the photoconductive layer 9 needs to be at least one order of magnitude larger than the resistance of the liquid crystal layer 3. Although it depends on the resistivity and resistivity, the dark resistivity of one photoconductive layer 9 is usually approximately:
1o・Ωmouth or more is required, preferably IgllΩam
That's all.

Changes in the liquid crystal structure depend on the current effect like the D8M, %tL, TN method (twisted nematic effect 1D
There are methods based on electric field effects such as sub-controlled birefringence effect method, phase transition method, and OR (guest-host effect) method, and a liquid crystal suitable for each method is selected and applied.

Next, another embodiment will be described with reference to FIGS. 4 and 5.

Place three color filters consisting of R (red), B (blue), and G (green) on the transparent hole of the liquid crystal light valve, which has the same structure as in Figure 1, using the following procedure. 5
By forming and arranging them in stripes as shown in the figure, a liquid crystal light valve for color display as shown in the schematic cross-sectional view of FIG. 4 can be obtained.

Incidentally, among the reference numerals in FIG. 4 that are the same as those in FIG. 1, all refer to the same components as in FIG. 1, and the explanation thereof will be omitted here.

Basic dye 70xine a (manufactured by Bm81), which is a red coloring material that is easily soluble in water and other organic solvents, was deposited to a thickness of 5 mm using a vacuum evaporation method at a vacuum level of 5X.
10'?・rr), followed by polyparaxylylene (manufactured by Union Carbide) and reaction vessel for IIF (0,
The film was formed at a temperature of 1 Te·rr (25° C.) to a thickness of 2060 m′. Later, 7 Otoresist (product name:
? PR101 (manufactured by Tokyo Ohka Kogyo Co., Ltd.) was spin-coated at 1000 rPe (65001), and subjected to exposure and development using a conventional processing method to form a streaky pattern.

This was etched using a 2 x 10”?rr oxygen plasma etching device (manufactured by IG Co., Ltd., product name: PLAIMOD).
), the unnecessary colored layer could be removed in about 60 minutes.

Due to the protection of Hala + Silylene, the damage to the dye layer due to photoresist solvent and development was completely removed. Next, copper 7 talocyanine was added as a blue dye to 5000'rr.
Since @7 talocyanine, which was vapor-deposited to a thickness to form M, is a pigment and has particularly excellent resistance to 7-osire resist, it was possible to directly coat the photoresist. Accurately align the mask for the previous red dye stripe pattern, perform exposure and development treatment to form an etching resist layer on the blue pattern area, and remove the unetched area using oxygen plasma etching. Ta. The oxygen pressure is 2 x 10”Tovr and the time required is about 1o
It was a minute. Further, on top of that, a layer of p-cyanine was deposited to a thickness of 80 degrees by vapor deposition, followed by #!
A film was formed by polymerizing varaxylylene using the same method as for the first color red, and the photoresist pattern was formed and etched using oxygen plasma (2×10'?.rr). The time required for this was 70 minutes.

Light from a halogen lamp is projected from the color filter side onto the thus obtained liquid crystal light valve shown in FIG. 4 from which the liquid crystal layer 3 has been removed, and the light from the halogen lamp is magnified 20 times and projected onto a screen (not shown). As a result, a clear colored stripe image consisting of 1, G, and B was obtained. It is also possible to do so. The method for forming each filter is also not limited to the above-described method.

Further, the embodiment shown in FIG. 6 will be explained.

As shown in the schematic cross-sectional view in Figure 6, 70
59 as a transparent electrode formed on one side of the slide glass 101! 1356M on Te0 membrane (manufactured by Itabata Vacuum Co., Ltd.) 102
The pace pressure is reduced by the R1 discharge decomposition method of Bs.
X 10 'Tart or less, 11114/m-
While flowing a 10-stroke mixed gas at a flow rate of 20800M,
Gas pressure, ~0.1! An amorphous silicon film 103 having a thickness of 5 μm and exhibiting excellent photoconductivity was formed under the following conditions: rr: discharge power, 10 W: substrate temperature, ~200° C. Next, a film was formed to a thickness of 100 mm by vacuum evaporation. At this time, if the degree of vacuum is 10"?trr or more, the mirror-like U film can be
■The reflection mirror 104 was formed by dividing the blades into 10μ blades with a width of 90μm. On the upper surface of the reflection mirror 104 thus obtained,
Using the 6MMm 11 discharge decomposition method, glH4/l low 1010 gas was converted to 58 (IOM, 100% (D NH
*, while flowing l/X at a flow rate of 20g0011[, the gas pressure is 0.15'! '・rr: discharge power, 10W
: Substrate temperature, ~zoo℃: Thickness 5ooooH
4 films 10B were formed.

This 11114 film had good light transmittance and IIIL gas insulation properties. Next, after forming a film with a thickness of 0B on the IIINJ film 10B, one opening area of 80 μm was formed in the U film tOS by photo-etching.
Through holes 107 having a diameter of 80 μm were formed at regular intervals as shown in the figure.

In addition, Imm formed on one side of another slide glass 108
(am) Apply a glycerin solution containing water to the 01 membrane 109, overlay it on the 10ft membrane so that the top of the stmN411 becomes conductive, and then
A DC voltage sov was applied between the membranes 109 and 19011102 for 2 seconds with tOS being the negative electrode, and at that time, the results were calculated for the cases in which projection light was projected using a halogen lamp and in the case in which no projection light was projected at all. , changes in surface potential were measured with an electrometer. The results are shown in FIG.

At this time, the projection timing of the projection light is after the voltage application is stopped and after the OSS, and the energy of the projection light is 100mW/
It was awt.

The solid line in Figure 97 indicates the case where no projection light is projected and
This is a common result when the light is projected from the slide glass 10B (il).The dotted line shows the result when the projection light is projected from the slide glass 101 side, and immediately after the projection light is projected (approximately 1 After -1 and -1), a rapid decrease in surface potential was observed.

From the experiment of this example, it can be seen that the reflective mirror performance of the present invention is improved.

In this embodiment, the a-deposited film range of the reflecting mirror 104 is effective. A thinner film is preferable because it prevents the film from peeling, improves the etching speed, and provides uniformity in the laminated liquid crystal layer. Therefore, a more desirable film thickness is 1000 μm. In addition, it is desirable that the thickness of the 81mNA film 105 (insulating layer) be thinner in order to reduce the voltage drop in the insulating layer, but there is a limit to eliminating leakage current in the insulating layer, and this limit is It varies depending on the voltage and the material forming the insulating layer. However, when considering the distribution of the driving voltage, it is desirable that the thickness be equal to or less than the thickness of the amorphous silicon film 103 (photoconductive layer).

In this example, the through hole 107 is 80μm×8Gμm and 1
Although they are formed at a pitch of 100 It, the resolution can naturally be increased by making the aperture area smaller and the pitch smaller.

In the present invention explained in these embodiments, in order to prevent projection light from entering the photoconductive layer and signal light from entering the liquid crystal layer, the area of the reflecting mirror is larger than the opening area of the through hole. It is designed to. At this time, it is desirable that the overlap between the two is at least larger than the thickness of the insulating layer interposed between them.

Furthermore, in the present invention, a transparent electrode and a light-shielding layer (
In some cases, well-known liquid crystal alignment treatment can be applied to the surface of the color filter).In the present invention described in detail above, 1. In particular, the structure of the reflection mirror in the device is simplified, so the entire device is compact. It has a simple structure, the manufacturing technology is simple, and the yield is similar to that of china clay.

1. Extremely high quality projection images can be provided with a simple structure.

3. When driving with a DC voltage, it was necessary to form a so-called carrier trap level in the photoconductive layer in the conventional method, but in the present invention, since the reflecting mirror is a conductor, this trap level is It is not necessary to provide a separate carrier trap level within the photoconductive layer, and the number of manufacturing steps can be reduced.

4. A color filter can be easily added using microfabrication technology, and as a result, a liquid crystal light valve for high-resolution color display can be provided.

Various effects such as this can be obtained.

[Brief explanation of the drawing]

1 to 6 are explanatory diagrams relating to embodiments of the present invention, and FIG. 7 is a graph showing experimental results in the embodiment shown in FIG. In the figure, ia % tb, 101.108 is a transparent substrate, 2a 2bS102.109 is a transparent electrode, 3 is a liquid crystal layer, 5.106 is a light shielding layer, 6.107 is a through hole, 7.
105 is an insulating layer, 8.104 is a reflective mirror, 9.103
is a photoconductive layer, and KOF, Go'P, and BOF are colored filters.

Claims (1)

[Scope of Claims] 11. An electro-optical device comprising a crystal layer and a photoconductive layer and converting an input image of light into a projected image by a charging effect, comprising: a light-shielding layer having a plurality of through holes corresponding to pixels; A plurality of reflective guns facing each of the through holes and separated from each other are interposed between the liquid crystal layer and the photoconductive layer through a light-transmitting insulating layer that is in contact with one side of the light-shielding layer. An electro-optical device characterized by: 2. The electro-optical device according to claim 1, wherein a colored optical filter is disposed in the through hole.