JPH05142585A - Display panel - Google Patents

Abstract

PURPOSE:To obtain a display panel capable of maintaining good brightness and contrast by adjusting its transmissivity in accordance with the brightness of surroundings. CONSTITUTION:The thickness of the coating film 11 of an electrochromic element is controlled to about 2mum. An ITO film 11a, an iridium oxide film 11b, a tantalum pentoxide film 11c, a tungsten oxide film 11d and an ITO film 11e are successively vacuum-deposited on the surface of a panel glass 10 of a cathode-ray tube while impressing a negative charge to form the film 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display panel such as a cathode ray tube or liquid crystal.

[0002]

2. Description of the Related Art The image quality of a display panel such as a cathode ray tube or liquid crystal is greatly influenced by the transmittance of the panel.

That is, in the display panel, the higher the brightness, the brighter the image becomes, which is preferable. In order to increase the brightness, it is necessary to increase the transmittance of the panel. However, if the transmittance of the panel is too high, when the surroundings are bright, external light is reflected on the back surface of the panel and the contrast is lowered.

Under these circumstances, in the case of a normal cathode ray tube, considering both brightness and contrast, it is about 10 mm.
A panel having a thickness of 30 to 90% and a transmittance of 30 to 90% is used, and is selectively used according to the application.

[0005]

However, even if the display panel has an optimum transmittance under a certain brightness, if the brightness around the display panel changes greatly, the required transmittance also increases. As a result, the good brightness and contrast cannot be maintained.

The present invention has been made in view of the above circumstances. An object of the present invention is to always maintain good brightness and contrast by adjusting the transmittance according to the ambient brightness. It is to provide a possible display panel.

[0007]

The display panel of the present invention comprises an electrochromic film formed on the outer surface thereof, and a voltage is applied to the film to form a film.
It is characterized in that the transmittance can be adjusted.

The electrochromic device is a device utilizing a specific electrochemical reversible color development reaction,
When a voltage is applied, the transmittance changes according to the magnitude of the voltage and the application time.

The coating film of the present invention is formed, for example, by sequentially laminating a transparent electrode layer, an oxidative coloring layer, an electrolyte layer, a reduction coloring layer and a transparent electrode layer on the surface of the panel, and a power source is connected to each transparent electrode layer. Voltage is applied. The material of the transparent electrode layer is indium tin oxide (ITO), the material of the oxidation coloring layer is iridium oxide, the material of the electrolyte layer is tungsten pentoxide, and the material of the reduction coloring layer is tungsten oxide. Used, these films are usually formed by vacuum vapor deposition, chemical vapor deposition, and dipping.

[0010]

According to the display panel of the present invention, a voltage is applied to the film of the electrochromic element formed on the outer surface of the panel according to the brightness of the surroundings to adjust the transmittance thereof. It is possible to always maintain good brightness and contrast.

In the present invention, the transmittance of the coating film of the electrochromic element may be adjusted by a simple switch operation, but by connecting a photodetection mechanism equipped with a microcomputer to the display panel, automatic transmission can be achieved. It is also possible to adjust the transmittance automatically.

[0012]

EXAMPLES The display panel of the present invention will be described in detail below based on examples.

FIG. 1 is a partial sectional view of a cathode ray tube display of the present invention, and 10 is a panel glass of the cathode ray tube,
Reference numeral 11 denotes a film of the electrochromic device. The coating film 11 of the electrochromic element has a thickness of about 2 μm, and the ITO film 11a, the iridium oxide film 11b, the tantalum pentoxide film 11c, the tungsten oxide film 11d, and the ITO film 11e are formed in this order on the surface of the panel glass 10. Each material was formed by vacuum evaporation while applying an electric charge.

A voltage is applied to each of the ITO films 11a and 11e from a power source (not shown) through a switch (not shown). With this switch, each I
The voltage applied to the TO films 11a and 11e can be switched between positive and negative.

That is, when a positive voltage is applied to the ITO films 11a and 11e, which are transparent electrode layers, by operating a switch, the iridium oxide film 11b, which is an oxidation coloring layer, develops a color by an oxidation reaction, and at the same time, it is a reduction coloring layer. The tungsten oxide film 11d is colored by the reduction reaction, and the transmittance is reduced. On the contrary, when a negative charge is applied to the ITO films 11a and 11e, the color is instantaneously erased and the transmittance is restored.

First, after measuring the transmittance of this display panel at a wavelength of 400 to 700 nm which is a visible light region, a switch is operated to apply a voltage of 1.6 V for 1 minute and 3 minutes.
It was applied for a minute, and the transmittance at a wavelength of 400 to 700 nm was measured, and each transmittance curve is shown in FIG.

As is apparent from FIG. 2, the transmittance curve b for which the voltage was applied for 1 minute was lower than the transmittance curve a for which the voltage was not applied, and the transmittance curve for which the voltage was applied for 3 minutes was lower. c is lower, and it can be understood from this fact that the longer the voltage application time, the lower the transmittance.

The transmittance of the display panel is measured by a spectrophotometer.

Although the cathode ray tube display panel of the present invention has been described in detail above, it is needless to say that the present invention is not limited to this and can be applied to other display panels such as liquid crystal.

[0020]

As described above, the display panel of the present invention can always maintain good brightness and contrast by adjusting the transmittance according to the brightness of the surroundings.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of a cathode ray tube display panel of the present invention.

FIG. 2 is a transmittance curve for wavelengths of 400 to 700 nm when the voltage application time is changed for the display panel of FIG.

[Explanation of symbols]

 10 panel glass 11 electrochromic film

Claims (1)

[Claims] 1. A display panel characterized in that a coating film of an electrochromic element is formed on an outer surface thereof, and a transmittance can be adjusted by applying a voltage to the coating film.