JPH1152U - Electronic device and liquid crystal display device - Google Patents

Abstract

(57) [Summary] [Object] To protect a thin film electronic device and a liquid crystal display device using a translucent substrate from ultraviolet rays and static electricity. A thin film electronic device is provided on one surface of a light transmitting substrate, and a DLC film is provided on the other surface of the substrate. The liquid crystal display device further includes a pair of substrates sandwiching a liquid crystal layer, and at least one of the pair of substrates is a light-transmitting substrate provided with a DLC film on a surface thereof.

Description

[Detailed description of the invention]

[0001]

[Industrial applications]

 The present invention relates to an electronic device using an organic material, such as a plastic film, which is a flexible, flexible, light-transmitting material, and a DLC film (diamond-like carbon), ie, an amorphous material, on the surface of the plastic film. The present invention relates to a device in which a diamond-like carbon film is coated.

[0002] The present invention relates to a technology applied to electronic devices such as a film-like solar cell, a liquid crystal display device, and a thin calculator made of a plastic plate, which are highly translucent and flexible. is there.

[0003]

[Prior art]

 Electronic devices using a plastic film having transparency and flexibility or a thin plastic film having a thickness of several millimeters include a film solar cell, a liquid crystal display device, and a card-type calculator.

For example, as a flexible solar cell, polyacrylate (PAR), polyether sulfone (PES), or the like can be used instead of a glass substrate used in a conventional thin-film solar cell (for example, an amorphous silicon solar cell). What uses what is called engineering plastic having flexibility, that is, flexibility is known.

A solar cell using such a plastic film as a substrate has a wide range of applications due to its flexibility, and has advantages such as lightness and no cracking.

[0006] Card-type calculators using a plastic film having a thickness of several millimeters but having no flexibility but having a thickness of several millimeters are widely and widely used.

[0007]

[Problems of conventional technology]

 The following problems have been pointed out with respect to the above-described conventional electric equipment using a translucent plastic film as a substrate, for example, a film-shaped solar cell. (1) The plastic surface is easily damaged. (2) The plastic film absorbs ultraviolet rays and deteriorates. As a result, the transparent one becomes gray, and when a plastic film is used on the light incident side, the photoelectric conversion efficiency decreases.

In general, a liquid crystal display device or a thin film electronic device (for example, an integrated circuit) is susceptible to ultraviolet light (380 nm or less) which is short-wavelength light. This is also evident from the fact that the display function deteriorates when the liquid crystal device is exposed to sunlight.

It is a well-known fact that electronic devices are generally susceptible to static electricity. This is a serious problem in an electronic device using a plastic film which is easily charged.

[0010]

[Problems to be solved by the invention]

 The present invention is intended to protect the surface of a plastic film exposed on the surface of an electronic device using a transparent plastic film, which is a light-transmitting organic material having a light-transmitting and wide application range, as a substrate. The purpose of the present invention was to prevent the plastic film from being deteriorated due to absorption of heat, prevent the electronic device parts from being directly exposed to ultraviolet rays, and prevent the plastic film from being charged with static electricity. I do.

[0011]

[Means for Solving the Problems]

 The present invention is an electronic device characterized by using a translucent substrate material having a DLC film formed on at least one surface.

The translucent substrate material having a DLC film formed on at least one surface is generally referred to as an electronic device using a transparent plastic film, which is a translucent substrate material, as a substrate. Since the strength is provided by a transparent plastic film, and the transparent plastic film is used as a substrate, for example, a photoelectric conversion layer and a liquid crystal display layer are provided, and the other surface is exposed to the outside. The translucent material exposed on the outside (for example, the surface of a transparent plastic film) is coated with a DLC film (diamond-like carbon), that is, an amorphous diamond-like carbon film.

The following effects can be obtained by coating the exposed surface of the transparent plastic film with the DLC film. (1) The surface of the plastic film is less likely to be scratched. (2) The DLC film absorbs light of 400 nm or less, so that ultraviolet rays can be cut off. Could be prevented. (3) Since the DLC film has a specific resistance of 10 ⁵ to 10 ¹⁴ Ωcm, electrostatic charging can be prevented. A DLC film having a Knoop hardness of 500 to 600 kg / mm ² was used.

As the electronic device, a photoelectric conversion device (for example, a solar cell), a liquid crystal display device, and other thin film electronic devices can be used.

Further, a substrate material having a light-transmitting property is not necessarily required to have flexibility. The reason is that the use of a light-transmitting plastic substrate alone has characteristics such as light weight, easy handling, and high safety compared to an electronic device using a conventional glass substrate.

[0016]

【Example】

 [Example 1] This example has a transparent plastic film coated on one side with a DLC film and a photoelectric conversion layer provided on the other surface of the plastic film not coated with the DLC film. This is a film-shaped solar cell.

FIG. 1 shows the structure of this embodiment. In this embodiment, a polyarylate (12) of a transparent plastic film, which is a flexible and translucent organic material, provided with a DLC film (11) on the side where light (10) is incident, and It comprises a transparent conductive film (13) as a photoelectric conversion device provided on an arylate (12), a photoelectric conversion layer (14) made of amorphous silicon, and a back electrode (15).

The thickness of the DLC film (11) is 1500 ° in this embodiment. The photoelectric conversion device has the same configuration as the photoelectric conversion portion of a film-shaped amorphous silicon solar cell having a known configuration.

As shown in FIG. 1, in the case of a photoelectric conversion device of the type in which light is incident from the side of the transparent plastic film as a substrate, the transparent plastic film is exposed to the ultraviolet rays (wavelength 380 nm or less) described in the above-mentioned problem of the prior art. The problem of deterioration and deterioration of light transmittance can be prevented.

FIG. 2 shows the wavelength dependency of the light transmittance of a general transparent plastic film (100 μm thick). From this figure, it can be seen that a general transparent plastic film absorbs light having a wavelength of 400 nm or less, that is, ultraviolet rays well.

The solar cell having the configuration shown in FIG. 1 is widely used because the photoelectric conversion layer can be protected by a transparent electrode.

An important point of the present invention is that the DLC film can be used as a filter for cutting light of 400 nm or less.

The experimental fact that this DLC film absorbs light of 400 nm or less will be described below. FIG. 3 shows the dependency of the light transmittance on the wavelength of the incident light in a DLC film having a thickness of 1500 °. FIG. 3 shows that light having a wavelength of 400 nm or more has a transmittance of 90% or more, but light having a wavelength of 400 nm or less sharply decreases its transmittance.

Further, the DLC film has a characteristic that it is hardly deteriorated since it has a composition mainly composed of carbon bonds, and that there is almost no change in light transmittance even when ultraviolet rays are absorbed.

Therefore, it is effective to make the DLC film which is hardly deteriorated in front of the transparent plastic film absorb light of 400 nm or less, that is, ultraviolet light.

FIG. 4 is a graph showing the relationship between the standard value and the incident light wavelength, where the highest efficiency of the amorphous silicon solar cell is set to 1, from which the efficiency of the amorphous silicon solar cell is shown. It can be seen that even if light having a wavelength of 400 nm or less is cut, no significant reduction in efficiency occurs.

The structure of the present invention has an effect of cutting ultraviolet rays of the DLC film in a photoelectric conversion device of a type in which light enters from the transparent plastic film substrate side as shown in FIG. The DLC film (11) can be used as a surface protective film and an antistatic film for a plastic film substrate that is easily charged even in a solar cell in which no light is incident (FIG. 5).

It is needless to say that the configuration of the present invention is not only applied to a solar cell, but can also be applied to a light-transmitting and flexible substrate such as a photosensor using a transparent plastic film substrate. Nor.

As the photoelectric conversion layer, not only a PIN structure but also a generally known photoelectric conversion structure such as PIP or NIN can be used.

Further, the type of semiconductor is not limited to amorphous silicon, and polycrystalline silicon, single crystal silicon, and other compound semiconductors can be used.

In the manufacturing method of this embodiment, it goes without saying that any known film forming method may be used. This is evident from the fact that the feature of the present invention is that the DLC film is used as a physical, electrical, and optical protective film of the transparent plastic film.

In the present embodiment, polyarylate (PAR) is used as the transparent plastic film, but polyether sulfone (PES), polyethylene terephthalate (PET), etc. can be used, and if the purpose is to cut off ultraviolet rays. For example, another transparent substrate (for example, a glass substrate) may be used instead of the transparent plastic film.

By adopting the structure of the present invention, the reliability of a film-shaped solar cell using a transparent plastic film as a substrate could be improved.

If attention is paid to the non-charging property of the DLC film, a plastic film can be used as a surface protection film for electronic devices and the like, a deterioration preventing film due to ultraviolet rays, and an antistatic film for static electricity. In this case, DLC films may be provided on both sides of the transparent plastic film as needed.

Example 2 In this example, a transparent plastic film having a DLC film coated on one surface and an electrical film provided on the other surface of the plastic film not coated with the DLC film were used. In an electronic device characterized by having a layer having an action, in a case where a layer having a liquid crystal display function as a layer having an electrical action, that is, a layer having a liquid crystal layer and electrodes, a driving circuit, and the like is used. is there.

The driving method of the liquid crystal display device may be a simple matrix type or an active matrix type, and the type of liquid crystal may be a TN type, STN type, or FLC type.

[0037] The transparent plastic film may or may not have flexibility.

FIG. 6 shows the structure of this embodiment. In this embodiment, a transparent plastic film, polyarylate (PAR) (3 mm thick) (61), and a DLC film (63) having a thickness of 1500 mm on the display side of a liquid crystal display device comprising a liquid crystal display layer (62). It is provided in. The liquid crystal display layer has a simple matrix configuration using FLC (ferroelectric liquid crystal).

In the figure, (64) is a lower electrode, and (67) is an upper electrode. A matrix was constructed with these two electrodes. (65) and (66) are alignment films, and (68) is a ferroelectric liquid crystal (FLC).

It goes without saying that the configuration of another liquid crystal display device, for example, a TFT type active matrix type liquid crystal display device may be used as the liquid crystal layer (62).

In this embodiment, the DLC film is provided only on the portion exposed to sunlight or the like. However, if the DLC film is used as an antistatic film, the DLC film is provided on the surface opposite to the liquid crystal layer of (61). You may.

By adopting the configuration of the present embodiment, the surface protection of a card-type calculator or a card-type liquid crystal display device using a plastic film, and the deterioration of the liquid crystal layer due to ultraviolet rays (wavelength 380 nm or less) which is problematic when used outdoors. (When the liquid crystal layer is deteriorated by ultraviolet rays, the display is blurred or the contrast is lowered).

Further, since the static electricity is not charged, the internal IC and the like are not destroyed by the static electricity.

In order to prevent static electricity from being charged, as shown in FIG. 7, the entire surface of the electronic device (71), for example, a card-type calculator may be entirely covered with the DLC film (72).

In this case, the liquid crystal display section of the card-type calculator also has a feature that ultraviolet rays can be cut.

It is also effective to coat the DLC film on the surface of a substance which should not be exposed to ultraviolet rays, that is, a substance which is deteriorated when irradiated with ultraviolet rays.

When a surface of a general light-transmitting substance is coated with a DLC film, a filter that cuts ultraviolet rays can be formed.

Similarly, a substance that should not be charged may be coated with a DLC film to form an antistatic film.

[0049]

[Effect of the invention]

 In an electronic device using a light-transmitting substrate material having the structure of the present invention, by providing a DLC film on the surface of the substrate material, the quality of the substrate material (generally, a transparent plastic film) and the light-transmitting property are improved. UV rays that could cause failure or deterioration of electronic devices mounted on or through a conductive substrate could be cut, and an electronic device having surface protection and antistatic effects could be obtained. .

[Brief description of the drawings]

FIG. 1 shows an example of a photoelectric conversion device to which the configuration of the present invention is applied.

FIG. 2 shows the relationship between the light transmittance of a polymer rate which is a transparent plastic film and the wavelength of transmitted light.

FIG. 3 shows the relationship between the light transmittance of a DLC film and the wavelength of transmitted light.

FIG. 4 shows a relationship between a standard value of efficiency of an amorphous silicon solar cell and a wavelength of incident light.

FIG. 5 shows another example of the first embodiment.

FIG. 6 shows a structure of a second embodiment.

FIG. 7 shows an example of applying the present invention.

[Explanation of symbols]

 10 ... incident light 11 ... DLC film 12 ... transparent plastic film 13 ... transparent conductive film 14 ... photoelectric conversion layer 15 ... backside electrode 61 ... transparent plastic film 62 ... Liquid crystal display layer 63 ・ ・ ・ Transparent plastic film 71 ・ ・ ・ Electronic device 72 ・ ・ ・ DLC film

Claims (2)

[Utility model registration claims] 1. An electronic device comprising: a thin film type electronic device provided on one surface of a light transmitting substrate; and a DLC film provided on the other surface of the substrate. 2. A liquid crystal display device comprising a pair of substrates sandwiching a liquid crystal layer, wherein at least one of the pair of substrates is a translucent substrate having a DLC film provided on a surface thereof. .