JPH0678930U - Liquid crystal display - Google Patents

Abstract

(57) [Abstract] [Purpose] In a transmissive liquid crystal display device including a liquid crystal display element section and a light source section, a disturbing electromagnetic wave generated in the light source is prevented from being emitted to the outside of the liquid crystal display apparatus, and To obtain a liquid crystal display device capable of preventing malfunction and adverse effects on the human body. [Structure] A film thickness of 15 made of crystallized indium tin oxide.
A transparent conductive thin film 21 having a surface resistance of ˜40 nm, a surface resistance of 100 to 500 Ω / □, and a transmittance of light having a wavelength of 550 nm of 80% or more is provided between the liquid crystal display element section 30 and the light source section 10.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a transmissive liquid crystal display device capable of suppressing electromagnetic waves generated from a light source.

[0002]

[Prior art]

 The transmissive liquid crystal display device includes a liquid crystal display element section and a light source section. The liquid crystal display element portion does not emit light by itself. Therefore, the light source section is provided on the back side of the liquid crystal display element section as seen from the user side. Transmission / non-transmission of the light generated from the light source section is controlled by the liquid crystal display element section which functions as a shutter. This controls the light that reaches the user, and the liquid crystal display device functions as an information display device.

As a light source in such a light source unit, a cold cathode tube (CLF), an electric luminescence (EL) element, or the like is used. These light sources are installed directly below or on the side of the back surface of the liquid crystal display device.

Here, in the case of a direct type in which a light source such as a cold cathode tube is installed directly below the back surface of the liquid crystal display element as viewed from the user, the light from the light source is evenly distributed in the plane of the liquid crystal display element. In order to disperse the light, a light diffusion sheet is provided between the light source section and the liquid crystal display element section. Or, if the light source is an edge light type (or side light type) that is installed on the side of the liquid crystal display element rather than directly below it, in order to reduce the unevenness of the light amount distribution due to the distance from the light source, A light plate and a light diffusion sheet are provided.

On the other hand, when electric luminescence (EL) is used as a light source, the light guide plate and the light diffusion sheet are not used because the light emitting particles inside the light emitting layer are excited by the pair of surface electrodes. A transparent conductive film is used as a surface electrode.

[0006]

[Problems to be solved by the device]

 Interfering electromagnetic waves are generated from the aforementioned light source in the transmissive liquid crystal display device. This electromagnetic wave is transmitted through the liquid crystal display element and is radiated to the outside, which causes a problem that a driving (TFT or the like) circuit of the liquid crystal display element malfunctions or adversely affects the human body.

The present invention solves the above problems, prevents the electromagnetic waves generated by the light source from being radiated to the outside of the liquid crystal display device, and can prevent malfunction of the drive circuit and adverse effects on the human body. The purpose is to get.

[0008]

[Means for Solving the Problems]

 A transmission type liquid crystal display device including a liquid crystal display element unit and a light source unit according to the present invention is made of crystallized indium tin oxide and has a film thickness of 15 to 40 nm, a surface resistance of 100 to 500 Ω / □, and a wavelength of 550 nm. A transparent conductive thin film having a light transmittance of 80% or more is provided between the liquid crystal display element section and the light source section.

The present invention provides a highly transparent conductive layer by directly forming a highly transparent conductive layer using the constituent materials interposed between these light sources and the liquid crystal display as a support, or by attaching a highly transparent conductive film, and grounding it. The inventor devised a liquid crystal display device with an electromagnetic wave shielding function.

By using the light diffusing sheet provided with the electromagnetic wave shielding function, the light guide plate, the transparent surface electrode, or the polarizing plate, the structure is simplified, and the TFT operation state or the human body is not damaged. It is a liquid crystal display device for the purpose of attenuating electromagnetic waves.

[0011]

【Example】

 FIG. 1 shows a display unit unit of a liquid crystal display device of a type directly below a cold cathode tube according to an embodiment of the present invention. In the figure, 10 is an edge light type light source using a cold cathode tube, 11 is a reflector, and 12 is a light guide plate. Reference numeral 20 is a light diffusion sheet composed of a transparent conductive layer 21 made of crystallized indium tin oxide having a film thickness of 30 nm, a substrate 22 made of a polyester film, and a light diffusion layer 23. Further, 30 is a display element section of the TFT system.

In the liquid crystal display device shown in FIG. 1, the light diffusion sheet 20 has an electromagnetic wave shielding function. That is, the disturbing electromagnetic wave generated from the light source 10 is absorbed by the light diffusing sheet 20 provided in the preceding stage of the liquid crystal display element section 30 and, of course, to the TFT drive circuit incorporated in the liquid crystal display element section 30. The human body is also supposed to attenuate the radiation of disturbing electromagnetic waves.

Further, here, by electrically grounding the transparent conductive layer 21, it is possible to further enhance the absorption of electromagnetic interference.

[0014]

[Effect of device]

 As described in detail above, the liquid crystal display device according to the present invention prevents the disturbance electromagnetic wave generated by the light source from being radiated to the outside of the liquid crystal display device and prevents the malfunction of the drive circuit and the adverse effect on the human body. A liquid crystal display device capable of being obtained can be obtained.

[Brief description of drawings]

FIG. 1 is a display unit section of a liquid crystal display device.

[Explanation of symbols]

 10 Light source 20 Light diffusion sheet 21 Transparent conductive layer 22 Substrate 23 Light diffusion layer 30 Display element section

Claims (1)

[Scope of utility model registration request] 1. A transmission type liquid crystal display device comprising a liquid crystal display element section and a light source section, which is made of crystallized indium tin oxide and has a film thickness of 15 to 40 nm and a surface resistance of 100 to 500 Ω.
A liquid crystal display device comprising: a transparent conductive thin film having a transmittance of 80% or more for a light having a wavelength of 550 nm and a space between a liquid crystal display element section and a light source section.