JP2003185821A - Filter having effect to lessen eye fatigue - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent dry eyes caused by light at long wavelengths (near IR rays) and polarized light emitted from a liquid crystal screen. <P>SOLUTION: Dry eyes can be prevented by sticking a dielectric multilayer film (ITO, ATO film or the like) or a resin plate having an amorphous structure on the front face of a liquid crystal screen. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling optical characteristics, which has an effect of suppressing eye fatigue such as dry eye that occurs when a liquid crystal screen is used.

[0002]

2. Description of the Related Art Protective films for cathode ray tubes and liquid crystals having a function of preventing electromagnetic waves and a function of blocking ultraviolet rays against light from display devices have been conventionally sold. However, in the case of a film for a cathode ray tube, it is meaningless to use it for liquid crystal screens having different light emission principles and display principles. Moreover, what is said to be for liquid crystal is also used for CRT, and its characteristics are no different from those for CRT. (Figs. 1 and 2)
In addition, large-sized liquid crystal screens are currently used in computer displays and televisions, and it is expected that they will become more and more familiar in the future. In such an environment, many people suffer from eye fatigue such as dry eye, but there is no filter that effectively protects the eyes from the LCD screen.

[0003]

The conventional method has a function of protecting the eyes from the cathode ray tube, but it is not effective for liquid crystal screens having different light emission principles and display principles. That is, it is necessary to specially design the eye protection filter in which the characteristics of light from the liquid crystal screen are fully taken into consideration.

[0004]

A conventional eye protection film for a cathode ray tube blocks ultraviolet rays (light having a short wavelength) emitted from the cathode ray tube. This is designed based on the emission characteristics of a cathode ray tube, but no ultraviolet rays are emitted from the liquid crystal screen. When the emission spectrum of the liquid crystal screen is measured, near infrared rays (light with a long wavelength) are often found instead of ultraviolet rays. (Fig. 3) Therefore, in the conventional method, ultraviolet rays were blocked, while
In the present invention, near infrared rays emitted from the liquid crystal screen are blocked. (FIGS. 4 and 5) Generally, light visible to human eyes is said to be in the range of 380 to 780 (nm) (visible range). Therefore, CRT,
A display device such as a liquid crystal screen only needs to emit light in this wavelength range. However, light having a wavelength longer than 780 (nm) (near infrared rays) is emitted from the liquid crystal screen. Since near-infrared rays are invisible, the pupillary reflex, which is a biological reaction, does not occur, and the infrared rays enter the eyes unknowingly. Moreover, the intensity of near-infrared rays emitted from the liquid crystal screen is irrelevant to the displayed color, so if a black color is displayed, for example, the pupil will expand and more near-infrared rays will enter the eyes. . It is considered that the near-infrared rays that enter the eye are absorbed by water and proteins, which are the main components of living tissues, and contribute to dry eye. (Fig. 7) By the way, the following table shows the water content (%) of the parts constituting the eyes of humans, cattle and rabbits.

[Table 1]

Also, unlike the natural light and the light of a cathode ray tube, the light from the liquid crystal screen is polarized light having an electromagnetic wave amplitude only on a certain surface. This light is a phenomenon seen in reflected light from the interface, and is a highly stimulating light that causes glare. In the present invention, by eliminating this polarization, light with low stimulating property can be supplied. (Figure 8)

Furthermore, by cutting the near infrared rays of 780 (nm) or more and depolarizing in combination, it is possible to effectively suppress eye fatigue.

A dielectric multi-layer film (ITO, ATO film, etc.) can be considered as a filter that cuts near-infrared rays of 780 (nm) or more and passes only light in the visible range. By sticking this film on the front surface of the liquid crystal screen, near infrared rays are cut off and only the light necessary for vision is visible.

A method using opal glass or the like is known for depolarizing light, but it is not practical to install opal glass on the liquid crystal surface. Therefore, a resin plate having an amorphous structure can be considered. In this case, since the polymer molecules in the resin plate are randomly arranged in all directions, polarization is eliminated by the dielectric relaxation process.

BEST MODE FOR CARRYING OUT THE INVENTION (Embodiment 1) An ITO film for blocking wavelengths longer than 780 (nm) was attached to an acrylic plate to prepare a filter. In the experiment, 20 volunteers worked for 1 hour each with a laptop computer to which a commercially available protective filter and a filter newly created by this patent were attached, and had the eyestrain degree compared. In order to keep the accuracy of the experiment, volunteers should not distinguish between commercial products and new products. When the commercial products are used in the first hour and when they are used in the subsequent hour. The effect was confirmed by conducting two experiments.

The results are shown in FIG. The effect according to the present invention is clear before and after use, and eye fatigue is reduced.

[Brief description of drawings]

FIG. 1 is a graph showing the transmission characteristics of a commercially available protective filter for cathode ray tubes.

FIG. 2 is a graph showing the transmission characteristics of a commercially available liquid crystal protection filter.

FIG. 3 is a graph showing emission spectra of a cathode ray tube and a liquid crystal.

FIG. 4 is a graph showing typical transmission characteristics of the filter of the present invention.

FIG. 5 is a graph showing an emission spectrum of liquid crystal when the filter of the present invention is used.

FIG. 6 is a graph showing an absorption spectrum of water.

FIG. 7 is a graph showing polarization characteristics of liquid crystal.

FIG. 8 is a graph showing the results of confirmation experiments using the filter of the present invention.

Claims (4)

[Claims] 1. A filter having an effect of suppressing light that is emitted from a liquid crystal screen and has no effect on eyesight and suppresses eye fatigue. 2. A filter having the effect of depolarizing the modified light from a liquid crystal screen and reducing irritation to the eye. 3. A filter having both claim 1 and claim 2. 4. The light emitted from the backlight of the liquid crystal screen,
A dedicated backlight filter that blocks light that does not affect your vision.