JPS61250619A - Optical element - Google Patents

Abstract

PURPOSE:To obtain a distinct image having high contrast and resolution and to eliminate the limitation in angle of field by sandwiching a gel layer which exhibits light scattering property by heating and exhibits light transmittance by cooling between a pair of substrates formed with heating elements on the surface of at least one substrate. CONSTITUTION:The distribution of polymer molecular chains is uniform in average in the state (low-temp. state) in which the gel layer 2 is not heated and therefore the incident ray 6-1 on the low temp. region 4 of the gel layer 2 passes approximately straightly through the gel layer 2 and is emitted from the substrate 1. On the other hand, the gel layer in the region in contact with or proximity to the heated part is also heated when the prescribed position of an IR absorption layer 8 is heated from the outside by the irradiation of, for example, an IR beam 5 according to an information signal. The distribution of the polymer molecular chains is then divided to a coarse region and a dense region and the gel layer exhibits the light scattering property. The incident ray 6-2 on the heated region 4a is therefore scattered. The heated region 4a restores the original light transmittance when the temp. falls.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a novel optical element, and particularly to an optical element that utilizes the light scattering properties of gel.

[Prior Art] and [Problems to be Solved by the Invention] In recent years, with the development of office automation (OA), display devices (displays) have been widely used in the field of office equipment. It is desirable for such a display device to be one that does not cause eye fatigue even when used for a long time. Conventionally,
As such a display element, an electrochromic display element (ECD) is used.
Non-emissive types such as liquid crystal display devices (LCDs) are known. However, EGD has the drawbacks of low display contrast, and LCD has even narrower viewing angles. Further, similar drawbacks occur when these are used as light modulating elements such as optical shutters.

The present invention was devised in view of the above drawbacks of conventional devices, and provides a single display device with a wide viewing angle, excellent clarity, and a high-quality device that does not cause eye fatigue even when used for long periods of time. , high contrast as a light modulation element,
The object of this invention is to provide an element that is less dependent on the angle of prior incidence.

[Means for Solving the Problems] Hereinafter, the basic configuration of the present invention will be explained using FIG. 1 corresponding to an embodiment.

In the figure, 1 is a substrate, 2 is a gel layer, 3 is a transparent protective plate,
Reference numeral 8 denotes an infrared absorption layer corresponding to a heat generating element. For the substrate 1, a material that transmits light such as glass or plastic is used when the optical element is a transmissive type, and when the optical element is a reflective type, a material that transmits light is used. , materials that do not transmit light such as semiconductors such as silicon, ceramics, metals such as aluminum, and opaque plastics, or materials in which a metal film is vapor-deposited on the surface of the above-mentioned transparent materials are used. . The gel layer 2 is a layer made of a network polymer (gel) containing a liquid, and the network polymer constituting this gel is mainly composed of a wood-loving material such as N-isopropylacrylamide, N, N
- A copolymer obtained by solution polymerization with the addition of a polyfunctional polymer such as methylene bisacrylamide or ethylene glycol dimethacrylate as a crosslinking component, or a hydrophilic polymer such as polyethylene oxide, polypropylene oxide, or polyvinyl alcohol as the main component. , trichloro-9-
) Polymers obtained by adding a crosslinking agent such as riazine, succinate chloride, glutaraldehyde, dimethylol urea, etc. and performing a polymer reaction are suitable. On the other hand, the liquids that make up the gel include water, alcohols such as methanol, ethanol, ethylene glycol, and glycerin, acetone,
Ketones such as methyl ethyl ketone are preferred.

The thickness of this gel layer 2 is tg-1000p,
ts is suitable, preferably 1IL1-100gm
is the optimal range.

As the heating element, for example, when infrared absorption heating is used as the heating means, an infrared absorption layer is used.

This infrared absorbing layer material is obtained by forming a film from various known inorganic or organic materials that are difficult to melt by themselves, such as Si, SiO, etc.
, 5iQ2, ZnS, As2S3. AI! 2oz,
NaF, Zn5e, Gd4b4e, carbon black, metal phthalocyanine, etc. are preferably used. The thickness of this infrared absorbing layer 9 is 500A to 100A.
00 A is a preferred range.

Further, as the transparent protection plate 3, a transparent body such as glass, plastic, dielectric, etc. is used. In addition, in order to improve the contrast, a visible light reflecting layer or a
A visible light absorbing layer (not shown) may also be provided.

[Operation] Next, the principle of operation (imaging, light modulation) of the optical element will be explained using FIG. 1 as well. Note that FIG. 1 shows an example of a transmission type.

First, in a state 8 where the gel layer 2 is not heated (that is, in a low temperature state), the distribution of polymer molecular chains is uniform on average, so the light ray 6-1 incident on the low temperature region 4 of the gel layer 2 is , passes through the gel layer 2 as is and is ejected from the substrate l. On the other hand, when a predetermined position of the infrared absorbing layer 8 is heated from the outside by, for example, irradiation with an infrared beam 5 in accordance with the information signal, the gel layer in the area in contact with or in the vicinity of this heated part is also heated, and the polymer molecular chains are heated. The distribution is divided into a linear region and a dense region, and shows light scattering properties. For this reason, heating area 4
The light ray 6-2 incident on a is scattered. This heating area 4a
returns to its original translucency when the temperature drops.

As the above explanation makes clear, the present invention is based on scattering of the gel layer (
Light modulation and display are performed by thermally controlling the non-transparent (non-transparent) and non-scattering (transparent) properties.

[Example] Example 1 FIG. 1 is a schematic configuration diagram showing a first example of the present invention. In FIG. 1, as a substrate l and a transparent protection plate 3,
Using a sufficiently clean glass plate with a thickness of 0.3t+s and a size of 50mm x 10cm, a film of Gd4b4 with a thickness of 1500A was deposited on the surface of the glass plate of the substrate 1 by sputtering.
An infrared absorbing layer 8 was formed by depositing an e (gadolinium-terbium-iron) layer. The surface of the infrared absorbing layer 8 of this substrate 1 and the transparent protection plate 3 were bonded and bonded to face each other at an interval of 10 gm using a Mylar film as a spacer. Next, 4.8g of N-isopropylacrylamide and 80mg of N,N-methylenebisacrylamide were dissolved in 601P of cold water, and further 501g of ammonium persulfate was dissolved in 601P of cold water.
Dissolve 150 gR of tetramethylethylenediamine
was added and degassed under reduced pressure to obtain a 7-mer solution. This 7-mer solution was immediately filled and sealed in the gap between the substrate 1 and the transparent protection plate 3, and left to stand for 30 minutes to form a gel layer 2, thereby producing an optical element.

When the thus obtained optical element was scanned and irradiated with a semiconductor laser beam with an output of 20 mW and a wavelength of 830 nm, focusing on the infrared absorbing layer 8 from the back surface of the element according to the information signal, a predetermined region of the gel layer 2 was detected. It was confirmed that the material changed to translucency. This is considered to be because the semiconductor laser beam is absorbed in the irradiated area of the gel layer 2 and converted into heat, thereby heating the gel layer that is in contact with each other. Note that the heating time by the semiconductor laser beam was instantaneous, and the gel layer 2 immediately showed its original translucency.

As a result of repeated irradiation experiments using laser beams, it was found that both reproducibility and signal response were practically sufficient.

Example 2 4 g of N-isopropylacrylamide, 70 mg of ethylene glycol dimethacrylate, and 0.5 g of hydroxyethyl methacrylate were dissolved in 60 μg of cold water, 50 mg of ammonium persulfate was further dissolved, 150 JLR of tetramethylethylenediamine was added, and the mixture was heated under reduced pressure. I degassed it. An optical element was produced in exactly the same manner as in Example 1 except that this solution was used as the monomer solution.

When the optical element thus obtained was subjected to imaging and light modulation experiments similar to those in Example 1, good results similar to those in Example 1 were obtained.

Embodiment 3 FIG. 2 is a schematic configuration diagram showing a third embodiment of the present invention. In this example, instead of the infrared absorbing layer 8 used in Examples 1 and 2, a resistive heating element layer 7 is arranged as a heating element on the surface of the substrate 1, and the resistive heating element is It is configured to control the heating of the layer 7, and is an example of a reflective type. The material for the resistance heating element layer 7 may be a metal compound such as hafnium boride or tantalum nitride, an alloy such as nichrome, or ITO (Ind.
Transparent oxides such as . Furthermore, as shown in the figure, an insulating layer (protective film) 9 is formed on the surface of this resistance heating element layer 7 between it and the gel layer 2.

In FIG. 2, a switch 2 connected to a resistance heating layer 7
0 is in the open state, so no current flows through the resistance heating element layer 7. Therefore, the incident light ray 8-1 passes through the gel layer 2 as is, is regularly reflected on the surface of the resistance heating element layer 7, passes through the gel layer 2 again, and is emitted from the transparent protection plate 3. On the other hand, a switch 20 connected to the resistance heating layer 7a
Since a is in the closed state, the resistance heating element layer 7a is heated by the current from the power source IO. Therefore, the incident light ray 8-2 is scattered as described above.

In this way, the resistance heating layer 7 is used instead of the infrared absorbing layer 8.
Even if it is used as a heat generating element, the effect is similar, and it is possible to perform image formation and light modulation as an optical element.

This example will be explained in more detail below.

FIG. 3 is a perspective view of a substrate showing a third embodiment of the present invention. In this embodiment, the substrate l and the transparent protection plate 3 are
The same material as in Example 1 was used. First, a tantalum nitride film with a thickness of 100 OA is formed by sputtering on the surface of the substrate l shown in FIG.
After baking a striped pattern of 20 pieces per shoe so as to be parallel to , the excess tantalum nitride film was selectively removed by etching treatment, and the remainder was used as the resistance heating layer 11. Next, an ITO film having a thickness of 2000 Å was laminated thereon by sputtering, followed by similar processing steps and predetermined patterning to obtain the striped electrode layer 12 shown in FIG. 3. At this time, the heating part (40p,
A portion of the ITO on the resistance heating layer was removed to obtain ta

Next, a 5i0 layer with a thickness of 2 gra is applied as an insulating layer 13 on top of the insulating layer 13.
The two films were laminated by sputtering. However, in order to attach lead wires to both ends of the resistance heating layer 11 later,
The test was carried out while shielding to prevent the 5i02 film from adhering. The substrate 1 provided with the resistance heating layer 11 and the transparent protection plate 3 were bonded to each other with a gap of log m using a Mylar film as a spacer. Next, 4.8 g of N-isopropylacrylamide, 80 mg of N,N-methylenebisacrylamide, and 30 mg of ammonium persulfate were added to 60 g of cold water.
(1) 150 µl of tetramethylethylenediamine was added to the mixture, and the mixture was degassed under reduced pressure to obtain a monomer solution. This 7-mer solution was immediately filled and sealed in the gap between the substrate 1 and the transparent protection plate 3, and left at room temperature for 30 minutes to form a gel layer 2, thereby producing an optical element.

An electrical pulse signal (with a frequency of 1 kHz) (
When a pulse height of 20 V and pulse length of 5 m5 ec) is input in accordance with the information signal, a predetermined position corresponding to the information signal responds by showing opacity, and writing is possible in accordance with the information signal. was confirmed.

As is clear from the above examples, the optical element of the present invention can obtain good characteristics in both the transmission type and the reflection type.

[Effects of the Invention] As explained above, since the optical element according to the present invention has excellent scattering properties, it is possible to obtain clear and high-resolution images with high contrast, and it is also possible to eliminate limitations on the viewing angle. . Therefore, even when used as a display device for a long time, the eyes will not feel tired, and since the gel layer is modulated by slight heating, the power consumption of the display device can be reduced. Furthermore, high frequency modulation is also possible.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing the first embodiment of the present invention;
The figure is a schematic configuration diagram showing a third embodiment of the invention, and FIG. 3 is a perspective view of a substrate showing the third embodiment of the invention. ■... Substrate, 2... Gel layer, 3... Transparent protective plate. 7.7a... Resistance heating element layer, 8... Infrared absorption layer,
11... Resistance heating layer, 12... Electrode layer. Figure 1 Figure 2

Claims (1)

[Claims] (1) An optical element in which a gel layer that exhibits light scattering properties when heated and exhibits translucency when cooled is sandwiched between a pair of substrates in which a heat generating element is formed on the surface of at least one of the substrates.