JPS6078424A - Optically color developing element - Google Patents

Abstract

PURPOSE:To enable the writing, long-time retention and simple vanishment of a fine and high density pattern by irradiating light on a two-layered structure consisting of a color developing layer and an ion feeding source formed in contact with the color develoing layer to develop color and by impressing voltage to retain the color. CONSTITUTION:Light is irradiated on a two-layered structure consisting of a color developing layer 1 and an ion feeding source 2 formed in contact with the layer 1 to develop color, and the color is retained by impressing an electric field to the structure. The color is vanished by impressing an electric field whose polarity is reverse to that of the electric field for color retention. Ultraviolet light of 500nm wavelength is used as the light irradiated. A pair of electrodes 3, 4 are attached to both sides of the structure. At least one of the electrodes 3, 4 transmits ultraviolet light. A film formed by sputtering mixed Li.W oxide in an Ar atmosphere used as the layer 1, and a film formed by sputtering mixed Li.W oxide in an Ar.O2 atmosphere is used as the source 2. The electrodes 3, 4 are made of ITO. A fine and high density optical memory or display can be retained for a long time with the resulting color developing element, and it can be simply vanished.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to erasable optical color elements useful for fine, high-density optical memories, displays, and the like.

Conventional Structures and Problems Conventionally, electrochromic elements, known as optical color elements, perform color development and erasure using electric fields, and form colored patterns depending on the shape of electrodes. It is also known that the coloring fades over time. When forming electrodes, there is a limit to the fineness of the pattern, and since it is necessary to take out the leads, there is also a limit to the density.

Unfortunately, it is difficult for conventional devices to be applied to optical memories, displays, etc. that require fine, high-density patterns, and they have only been used as simple display devices. In addition, most conventional optical memories use heat to cause structural changes, and only a few can be erased. was not sufficient for practical use. Even when the color is produced by light, the color cannot be maintained for a long time. The present inventors discovered that when light is irradiated onto a coloring element that has a two-layer structure in which a coloring layer and an ion supply source are brought into close contact, only the portion irradiated with light develops color, and this coloring portion is caused by an electric field applied to the two-layered structure. It was discovered that color development can be maintained for a long time by applying . Further, color development can be erased by applying an electric field of opposite polarity to that in the case of maintaining color development.

Based on this discovery, we invented an erasable optical coloring element that can create fine, high-density patterns and retain patterns for long periods of time.Objective of the InventionThe purpose of the present invention is to be able to write fine, high-density patterns. The present invention provides an optical coloring element that can be retained for a long time and can be easily erased.

Structure of the Invention The optical coloring element of the present invention has a two-layer structure consisting of a coloring layer and an ion supply source provided in close contact with the coloring layer, and is capable of developing color by irradiating it with light. , is characterized in that color development is maintained by applying an electric field to the two-layer structure. Further, color development can be erased by applying an electric field of opposite polarity to that in the case of maintaining color development. The inventors have confirmed that when irradiating light to develop color, the use of ultraviolet light having a wavelength of 500 nm or less makes it possible to develop color particularly effectively. In addition, a pair of electrodes, at least one of which is transparent to ultraviolet light, is provided between the two-layer structure, and light is irradiated through the electrodes that are transparent to ultraviolet light to cause color development, and a voltage is applied between the electrodes. The inventors have also confirmed that when the electric field is applied to the double layer to erase the color by holding the double layer between the two layers, the electric field is effectively applied to the double layer and erasing can be performed at a low voltage.

Further, the coloring layer is a sputtered film of a mixed oxide of lithium and tungsten in an argon atmosphere, and the ion source is a sputtered film of a mixed oxide of lithium and tungsten in an argon/oxygen atmosphere. It was confirmed that these are particularly effective as optical coloring elements of the present invention.

It was also confirmed that when an ITO film is used as an electrode that is transparent to ultraviolet light, it has good transparency in the visible region and is particularly effective.

Description of examples FIG. 1 shows a first embodiment of the optical coloring element of the present invention.

The coloring layer 1 and the ion source 2 are placed in close contact and sandwiched between electrodes 3 and 4 that are transparent to ultraviolet light.

Although this four-layer structure is formed on the substrate 6, the substrate 5 is not necessarily required as long as it is mechanically stable.

Also, regarding the electrodes 3 and 4, a sufficient electric field is applied to the coloring layer 1.
and the two-layer structure of the ion source 2, it is not necessarily necessary. The coloring layer 1 reacts with ions supplied from the ion supply source 2 to develop color.

In terms of reaction, the state from state a where the substance and ions in the coloring layer coexist to the state where they react with each other and develop color must change beyond the energy barrier A, as shown in Figure 2. Therefore, energy corresponding to the height E of the energy wall A is required. The principle of color development of the present invention is to cause the color development layer 1 to develop color by applying this energy with light.

When the light 6 is irradiated as shown in FIG. 3, the ultraviolet light 6 passes through the electrode 3 which is transparent to ultraviolet light and acts on the interface 7 between the coloring layer and the ion source. When the energy of this light gives the energy E, a reaction occurs and only the portion 8 irradiated with the light develops a color. Although the details of this reaction are unknown, it is thought that only the areas irradiated with light develop color due to the mechanism described above. The coloring section 8 applies an electric field to the two-layer structure. By applying a holding electric field that is maintained for a long time by applying a voltage to the electrodes 3 and 4, the energy of the coloring state is lowered to become 6-Btate in FIG.

In other words, the coloring state is lower in energy than the non-coloring state where the substance and ions of the coloring layer coexist.
Due to the effect of heat, the energy barrier is exceeded and the probability of transition from a colored state to a non-colored state a, that is, decolorization, decreases. By appropriately selecting the electric field strength, the colored pattern was maintained for a long time. The coloring section applies an electric field of opposite polarity to the two-layer structure to maintain the coloring, that is,
By applying a voltage of opposite polarity to the electrodes 3 and 4 to maintain the color development, the color is erased and returns to the state before color development. At the time of erasing, it is thought that a reaction opposite to the above reaction occurs, and by applying an electric field that provides energy greater than the above energy wall (E' in FIG. 2), the reverse reaction is caused.

l'hr of Li-''/i-0 mixture as the coloring layer
When a sputter-deposited film in an atmosphere is used, a sputter-deposited film of a Li-W-0 mixture in an Ar-02 atmosphere is used as the ion source, and an ITO film is used as an electrode. Using light, '51/
When irradiated with a density of approximately cJ or higher, it developed a blue color.

This color development was maintained for more than 1000 hours by applying a voltage of 2 .mu. with the color development layer side set as -. This coloring could be eliminated by applying a voltage of 5V to the ITO electrode. The film thickness is approximately 600 mm including the coloring layer and ion source.
It was 08. At the time of color development, it was observed that the transmitted light intensity of the He-Ne laser beam (6328 people) was attenuated by 10 dB or more, and a blue colored part was formed.

When erased by an electric field, the state returned to the state before color development and exhibited the same transmitted light intensity as the transmitted light intensity of the He--Ne laser beam in the state before color development. Specifically, Li-
Although only a sputtered film of a W-'O mixture is shown, the coloring layer may be any so-called electrochromic material, and the ion source is not limited to the above-mentioned materials. The ion supply source may be a liquid instead of a solid substance, as long as it contains ions that act on the electrochromic material. The irradiation light is not limited to excimer laser, but may be any light that provides energy on the wall plate of energy for reaction. Ultraviolet light with high energy is effective. The 0 irradiation light can color a fine pattern of about 1 μm through a lens aperture. Also, by scanning light,
You can also write complex patterns.

Effects of the Invention As described above, the present invention provides a coloring element having a two-layer structure consisting of a coloring layer and an ion supply source provided in close contact with the coloring layer. It was possible to achieve a fine, high-density pattern that could be held for a long time. In addition, by applying an electric field with the opposite polarity to the holding case described above, the colored part can be easily erased, making it effective for long periods of time for fine, high-density optical memory, display, etc.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional structural diagram of the optical coloring element of the present invention, and FIG.
The figure is an energy diagram of the optical coloring element of the present invention in each state, and FIG. 3 is a diagram of the coloring operation of the optical coloring element of the present invention due to light. 1... Coloring layer, 2... Ion supply source,
3,4・″. . . Electrode, 5 . . . Substrate, 6 . . . Light (
ultraviolet light).

Claims (1)

[Claims] (1) It has a two-layer structure consisting of a color-forming layer and an ion supply source provided in close contact with the color-forming layer, and the color is developed by irradiating light, and an electric field is applied to the two-layer structure. An optical coloring element that maintains the above-mentioned color development by applying an electric current. (2) The coloring part can be decolored by applying an electric field of opposite polarity to that for maintaining coloring to the two-layer structure consisting of a coloring layer and an ion supply source provided in close contact with the coloring layer. An optical coloring element according to claim 1, which is characterized by: (3) The optical coloring element according to claim 1, wherein ultraviolet light having a wavelength of 500 nm or less is used as the light. (4) A pair of electrodes, at least one of which is transparent to ultraviolet rays, are provided sandwiching a two-layer structure consisting of a coloring layer and an ion supply source provided in close contact with the coloring layer. An optical coloring element according to claim 1 or 2. (6) A sputtered film of a mixed oxide of lithium and tungsten in an argon atmosphere is used as the coloring layer, and a sputtered film of the mixed oxide of lithium and tungsten in an argon/oxygen atmosphere is used as the ion source. An optical coloring element according to claim 1 or 2, which is characterized by: (6) The optical coloring element according to claim 4, characterized in that an ITO film is used as the electrode that is transparent to ultraviolet rays.