JP2599445Y2 - Liquid crystal display - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission type liquid crystal display device capable of suppressing electromagnetic waves generated from a light source.

[0002]

2. Description of the Related Art A transmission type liquid crystal display device includes a liquid crystal display element section and a light source section. The liquid crystal display element 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 viewed from the user side. The transmission / non-transmission of the light generated from the light source unit is controlled by a liquid crystal display element unit serving as a shutter. Thus, the light reaching the user is controlled, and the liquid crystal display functions as an information display.

As a light source in such a light source section, a cold cathode fluorescent lamp (CLF) or an electric luminescence (E)
L) An element or the like is used. These light sources are installed directly below or beside the back of the liquid crystal display element.

Here, in the case of a direct type in which a light source such as a cold-cathode tube is installed immediately below the back of the liquid crystal display element as viewed from the user, the light from the light source is uniformly spread over the surface of the liquid crystal display element. For dispersion, a light diffusion sheet is provided between the light source unit and the liquid crystal display element unit. Alternatively, when the light source is an edge light type (or a side light type) installed beside the liquid crystal display element instead of directly below the rear surface, a light guide plate or a light guide plate is used to reduce non-uniform light amount distribution due to a distance from the light source. A diffusion sheet is provided.

On the other hand, electric luminescence (E
When L) is used as the light source, a light guide plate and a light diffusion sheet are not used because the light emitting particles in the inner light emitting layer are excited by the pair of surface electrodes, but a transparent conductive film is used as the surface electrode. Have been.

[0006]

The above-mentioned light source in the transmission type liquid crystal display device generates a disturbance electromagnetic wave. This electromagnetic interference wave is transmitted through the liquid crystal display element and radiated to the outside, causing malfunction of a driving (TFT etc.) circuit of the liquid crystal display element,
Alternatively, there is a problem of adversely affecting the human body.

[0007] The present invention solves the above-mentioned problem, and prevents a disturbance electromagnetic wave generated by a light source from being radiated to the outside of the liquid crystal display device, thereby preventing a malfunction of a driving circuit and an adverse effect on a human body. The purpose is to get.

[0008]

Transmissive liquid crystal display device including a liquid crystal display element unit according to the present invention a light source section Means for Solving the Problems], the light source
The edge light method is adopted for the part, and the thickness is 15 to 40 nm and made of crystallized indium tin oxide, and the surface resistance is 100 to
500 Ω / □ and 550 nm wavelength light transmittance 80%
The transparent conductive thin film described above is provided between a liquid crystal display element portion and a light source portion , and a liquid crystal display element of a light diffusion sheet.
To the opposite side .

The present invention provides an electromagnetic wave shield by directly forming a highly transparent conductive layer or attaching a highly transparent conductive film using the constituent material interposed between the light source and the liquid crystal display device as a support, and grounding. The present invention has been devised with a liquid crystal display device having functions.

By using the light diffusion sheet or the light guide plate, the transparent surface electrode, and the polarizing plate provided with the electromagnetic wave shielding function, the structure can be simplified, and the TFT operation state or the obstacle that may hinder the human body can be achieved. This is a liquid crystal display device for the purpose of attenuating electromagnetic waves.

[0011]

FIG. 1 shows a display unit of a liquid crystal display device of a direct-type cold-cathode tube type showing 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 reflection plate, and 12 is a light guide plate. Reference numeral 20 denotes a light diffusion sheet including a transparent conductive layer 21 made of crystallized indium tin oxide having a thickness of 30 nm, a substrate 22 made of a polyester film, and a light diffusion layer 23. Reference numeral 30 denotes a TFT display element portion.

In the liquid crystal display device shown in FIG. 1, the light diffusion sheet 20 has an electromagnetic wave shielding function. That is, the light source 10
The electromagnetic wave generated from the light is absorbed by the light diffusion sheet 20 provided in the preceding stage of the liquid crystal display element section 30 and is not only applied to the TFT driving circuit incorporated in the liquid crystal display element section 30 but also to the human body. Even so, the radiation of the obstructive electromagnetic wave is attenuated.

Here, by electrically grounding the transparent conductive layer 21, the absorption of the disturbing electromagnetic wave can be further enhanced.

[0014]

As described in detail above, the liquid crystal display device according to the present invention prevents the disturbing electromagnetic waves generated by the light source from being radiated to the outside of the liquid crystal display device, thereby causing a malfunction of the drive circuit and an adverse effect on the human body. Thus, a liquid crystal display device capable of preventing the above can be obtained.

[Brief description of the drawings]

FIG. 1 shows a display unit 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

Continuation of the front page (72) Inventor Masao Suzuki 4-3-1 Asahigaoka, Hino-shi, Tokyo Teijin Limited Tokyo Research Center (56) References JP-A-4-82485 (JP, A) JP-A-Hei 3-109237 (JP, A) JP-A-5-82822 (JP, A)

Claims (1)

(57) [Scope of request for utility model registration] 1. A liquid crystal display device and a <br/> light source unit according to the liquid crystal display element and the edge light type, consisting of crystallized indium tin oxide, thickness 15 to 40 nm, surface resistance A light-diffusing sheet , comprising a transparent conductive thin film having a transmittance of 100% to 500 Ω / square and having a transmittance of light of 550 nm wavelength of 80% or more between a liquid crystal display element portion and a light source portion;
A liquid crystal display device, which is arranged on the opposite side of the liquid crystal display element of the above .