JPS6019122A - Thin film display element - Google Patents

Abstract

PURPOSE:To attain high resolution and to make a device large-scale by using a BSO polycrystal thin film, which is grown with annealing, as a dielectric thin film which is sandwiched between transparent electrodes and is used. CONSTITUTION:A BSO polycrystal thin film 3' grown with annealing is used as the dielectric thin film which is sandwiched between transparent electrodes 2 and 2' and is used. The transparent electrode 2 is formed on a transparent substrate 1, and a BSO thin film 3 in the polycrystalline state is formed by ion plating or the like, and crystalline granules of polycrystal are grown by annealing, thus obtaining the BSO polycrystal thin film 3'. Then, a large-sized BSO element which has the same degree of orientation as BSO single crystal is obtained locally. An insulating layer 4 and the transparent electrode 2' are formed successively on the BSO polycrystal thin film 3' to obtain a thin film display element. Thus, the thin film display element which is thin and has a high recording density can be produced easily up to a large size, for example, A4 size. Since this display element has less variance of thickness and has high resolution, it is used as a hologram medium or the like.

Description

[Detailed description of the invention]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film display element. In particular, the present invention relates to a thin film display device useful as a light valve (ie, a light spatial modulation device). This display element utilizes Pockels effect gold.
-F ROM (Pockels R, eadOut
M'odulator) ty) Aim for high resolution and large size. BACKGROUND OF THE INVENTION As is well known, a light valve is a device that obtains a projected image by partially reflecting or transmitting a bundle of light rays emitted from a light source at a constant intensity depending on an input signal. Such devices include those in which the surface of an oil film or metal film is deformed by electronic means and combined with a Schlieren optical system, and 1# products. There are some that combine electro-optic crystals and polarizing plates. For example, Bi, 2S102, which will be discussed below.
o (hereinafter referred to as Boo) After applying a high electric field to the light valve using the halo crystal. It is characterized by writing information through development by irradiation with blue light, and then reading the information from the transmitted light by transmitting red light using a polarizing plate. Prior Art and Problems Conventionally, liquid crystal displays have been widely used. However, this type of light bulb is difficult to manufacture and expensive even though it is popular, so it costs about 5tM at most (large diameter). For example, attempts have been made to use single crystals such as KDP and BS0. However, the former is not only expensive, but also has insufficient characteristics unless used at a low temperature of, for example, -60 to -70°C. In addition, KDP.B80 single crystal requires processes such as crystal growth, slicing, and polishing, and in particular, machining such as slicing and polishing is a barrier to increasing size. .2 Also, the resolution of these elements depends on the thickness of the crystal, and in general, the thinner the crystal, the higher the resolution.Therefore, in conventional elements, slicing,
Element performance has been limited by limitations in machining such as polishing. Since the thickness of conventional elements is on the order of about 100 μm, a resolution of only 50 to 500 lines/throat can be obtained at most. Purpose of the Invention The purpose of the present invention is to solve the problems of the prior art as described above, and to solve the problems of the prior art.

[i.e., large area]. It is an object of the present invention to provide a light pulp, ie, R, film display element, which has a thin and uniform film thickness, is easy to manufacture, is low cost, and has fine characteristics. According to the present invention, there are provided a thin film display element comprising a dielectric thin film sandwiched between transparent electrodes, wherein the dielectric thin film is a BSO thin film and is grown by annealing. This can be achieved by a thin film display element characterized by a BSO polycrystalline thin film. That is, according to the present invention, after forming a transparent electrode on a transparent substrate, a polycrystalline BSO thin film is formed using a thin film technique such as sputtering or ion blating, and then annealing is performed to form a polycrystalline BSO thin film. Grow clumps. Grain clusters grow. A large B80 element is produced which has an orientation comparable to that of an 880 single crystal when viewed locally. After forming the large-sized BSO element, an insulating layer and a transparent electrode 71 are then formed to obtain a desired thin film display element. DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described with reference to the accompanying drawings. Here, the production of transmission type BSO thin film light pulp will be explained. First, as shown in FIG. 1, IT is placed on a glass substrate 1.
The O transparent electrode 2 is formed with a film thickness of about 2000 nm. However, since the glass substrate used as the transparent substrate and the transparent electrode to be formed on it are extremely thin, they must be as smooth as possible. When manufacturing a reflective light valve, an aluminum substrate, a silicon substrate, etc. can be used instead of a glass substrate. The ITO transparent electrode used here is often used in liquid crystal displays. Subsequently, a BSO polycrystalline film 3 is formed on the transparent electrode 2 by, for example, sputtering, ion blasting, E-gun, etc., by depositing 880'i (880'i) (FIG. 2, @sho). The formation of the BSO polycrystalline film 3 is 1, for example, an extremely small B80 film.
This can be done by exposing single crystal particles to an electron beam to eject BSO atoms and depositing them on the transparent electrode 2. The thickness of this polycrystalline film is several μm.
, preferably several times the wavelength of visible light. The particle size of the BSO crystal particles in this case is within the range of about several tens to several thousand particles. Note that if ion blating is used for BSO deposition, the crystallinity of the resulting BSO film can be further improved. Subsequently, the formed BSO polycrystalline film is annealed as shown in FIG. 3 to form a grown R8O polycrystalline film 5'.
form. In this grown film 3', the orientation of each crystal grain is uniform, and any misalignment due to grain boundaries can be completely eliminated from a macroscopic perspective. Annealing is not particularly limited and can be arbitrarily performed under conditions commonly used in this technical field as long as it does not destroy the previously formed transparent electrode 2. For example, about 30°C at about 300 to 450°C in an intoxicant atmosphere.
Advantageously, the annealing is carried out for a period of minutes. Furthermore, at the time of this annealing. Apply an appropriate magnetic field to adjust the crystal orientation. It is recommended to increase crystallinity. Subsequently, in order to prevent dielectric breakdown, an insulating film 4 is applied over the grown BSO polycrystalline film 3 (see FIG. 4). For example, 8102 is useful as this insulating film. This is because: 8i02 has good compatibility with the Si of 8SO below it, and is suitable as an insulating film. After moistening, as shown in Figure 5, L was added to the same analysis as in Figure 1.
7 to form an ITO transparent electrode 2'. In this way, a desired thin film element consisting of four layers is produced. Effects of the Invention According to the present invention, as understood from the above description, the pulp had the same characteristics as the conventional BSO single crystal light pulp. Moreover, a thin film display element with a larger diameter than that can be obtained relatively easily. This display element can actually be made as large as A4 size. This display element is also more than two orders of magnitude thinner than conventional display elements, and as a characteristic of BSO elements, the thinner the display element, the higher the recording density. , ) can exhibit an exceptionally high resolution on the order of about 100 lines per line. Furthermore, this display element is not manufactured by slicing 880 single crystal as in the past, so
The variation in film thickness is extremely small (for example, in the case of A5 size, variation in film thickness can be suppressed to the order of ±0.1 μm). The thin film display element of the present invention has a simple manufacturing process. Because there is
Of course, it is low cost. Since the thin film display element according to the present invention has a very high resolution as described above, it can be advantageously applied as a porographic medium. Jira r (, development is not required,
Since it can be read out electronically immediately after writing, it can be applied to computer terminals.

[Brief explanation of the drawing]

FIGS. 1, 2, 3, 4, and 5 are cross-sectional views showing the manufacturing process of a thin film display element according to the present invention in order. In the figure, 1 is a transparent substrate, and 2 and 2' are transparent electrodes. 3 is a BSO polycrystalline film, and 3' is a grown F3so polycrystalline film. and 4 is an insulating layer. Figure 5: Yan Mengzi Silver

Claims (1)

[Claims] 1. A thin film display element including a dielectric thin film sandwiched between transparent electrodes, the dielectric thin film being B S
(,) A thin film display element characterized in that it is a thin film and is a 7' (BSO) polycrystalline thin film grown by annealing.