JPH0453066B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to an optical filter that is incorporated in close proximity to the display screen of computers, televisions, and the like. More specifically, the present invention forms fine irregularities on at least the surface of the filament fiber cloth constituting the optical filter located on the opposite side of the screen to prevent surface reflection of light, that is, the so-called "flickering" phenomenon. The present invention relates to an optical filter that makes it possible to make the characters on the screen clearer and easier to see, and to minimize the fatigue and mental stress felt on the optic nerves even during long working hours. [Prior Art] Screens such as computer displays are made of highly reflective materials such as glass, so when the screen is darkened, surrounding lights (e.g. electric lights) are reflected and the screen is It has the disadvantage that the characters are difficult to read. In order to eliminate this drawback, as exemplified in Japanese Patent Application Laid-Open No. 126054/1983, a mesh screen (optical filter in the present invention) made from a dark-dyed filament such as nylon is placed on the screen. A method has been proposed to install the However, the material proposed by this method, which is made by dyeing a filament such as nylon in a dark color, and especially the synthetic fibers such as nylon and polyester used as mesh screen materials, have a high refractive index and a smooth fiber surface. Even if dyed in a dark color (especially black), the surface remains smooth and light reflection on the screen is prevented. A light reflection phenomenon will occur, and the expected effect will not be obtained. The present invention solves the problem by preventing the surface of the screen mesh from becoming smooth and providing unevenness. On the other hand, fine irregularities are formed on the surface of synthetic fibers, such as polyamide (nylon) and polyester fibers, to diffusely reflect light and improve the depth of color (color development), creating a waxy feel similar to that of silk. There is a way. For example, the alkali weight loss method disclosed in JP-A-57-205588 and JP-A-58-46189, and the low-temperature plasma method disclosed in JP-A-59-106587 and JP-A-59-15568, etc. This is it. However, these are mainly aimed at improving the color depth of black dyed fabrics such as clothing, especially formal wear, and do not suggest applications in the industrial materials field such as optical filters. [Problems to be Solved by the Invention] The present invention solves the problems in the prior art as described above, and provides a shadow mask with excellent performance that prevents light reflection on the screen and does not exhibit the so-called flicker phenomenon. This is what we are trying to provide. [Means for Solving the Problems] The present invention provides an optical filter made of filament fiber cloth and facing closely to a display screen to prevent light reflection, the optical filter comprising the filament At least the surface of the fiber cloth located on the side opposite to the display screen is etched to form fine irregularities. That is, the present invention is an optical filter that is provided in close proximity to a liquid crystal display screen of a computer or the like to prevent light reflection, and that is provided at least on the opposite side of the surface of the filament fiber cloth constituting the filter. Light reflection and surface flicker can be effectively prevented by roughening the surface on which it is located, for example, by chemical etching with a chemical or physical etching with a sputtering effect using low-temperature plasma, and having fine irregularities. Provides optical filters. By using the optical filter of the present invention, flickering and light reflection on the surface of the optical filter can be effectively prevented, characters on the display will become clearer, and the negative effects on the optic nerve and stress accumulation due to the so-called "flickering" phenomenon can be prevented. This can be minimized. The details of this invention will be explained below. Filament fiber cloths useful in constructing optical filters according to the present invention include natural fibers such as silk, inorganic fibers such as glass fibers, carbon fibers,
Regenerated fibers, such as metal fibers, such as viscose rayon, kyupra, etc., semi-synthetic fibers, such as g- and tri-acetate fibers, and synthetic fibers, such as nylon 6, Nanlon 66, polyester (polyethylene terephthalate, etc.) fibers, It consists of at least one type of filament fiber, preferably monofilament fiber, selected from aromatic polyamide fibers, acrylic fibers, polyvinyl chloride fibers, polyolefin fibers, and insoluble or hardly soluble polyvinyl alcohol fibers. The filament fibers preferably have a diameter of 25 to 150 microns; if the diameter is less than 25 microns, weaving becomes impossible due to fiber breakage, and if it is larger than 150 microns, it becomes difficult to see the characters on the display. The precision varies depending on the diameter of the fibers, but 50 to 400 fibers per inch is appropriate for both fibers and wefts. The filament fiber cloth useful in the present invention has fine irregularities formed on at least one side of each filament fiber for the purpose of preventing light reflection and flickering on the surface. Preferably, the fine irregularities cover half or the entire circumferential surface of the fiber surface without gaps, and the maximum diameter of the irregularities is 0.01 to 0.01 at the maximum frequency.
It is 0.5μ, preferably 0.1 to 0.5μ, and has 1 to 200 irregularities per square micron. The maximum diameter
If it is less than 0.01μ, light reflection and flickering on the surface will not be prevented, while if it is more than 0.5μ, the color will become dull, making it difficult to see the characters on the display, and the number of irregularities per square micron will also increase.
If the number exceeds 200, the physical strength of the fiber will be impaired. As a method for forming fine irregularities on the surface of filament fiber cloth, for example, when polyester filament is used, an alkaline reduction processing method using a caustic soda solution can be used.Other methods include a low-temperature plasma method, and a dyeing processing method can be used. Fine irregularities can be formed by processing either before or after dyeing. Alkaline weight loss processing includes batch-type methods such as hanging kneading method, high-temperature and high-pressure weight loss method, semi-continuous method such as pad roll method, pad dry method,
This can be carried out by a continuous method such as a padded steam method. However, the pad steam method is the most preferred method from the viewpoints of good workability, uniform processing, and little reduction in physical strength. The conditions for the alkali weight reduction process may be those commonly used and are not particularly limited. In order to obtain an efficient flicker prevention effect, it is necessary to reduce the fiber weight by 5 to 35%.
If the weight loss is less than 35%, the diameter of the unevenness formed on the surface is small and the number of unevenness per square micron is small, so flickering cannot be sufficiently prevented.
% or more, the fiber surface becomes rough and flicker prevention spots become noticeable. Furthermore, fine inorganic particles may be added to the filament fiber used in the present invention during melt spinning for the purpose of rapidly reducing alkali weight and forming effective irregularities. Low-temperature plasma treatment generally uses low-temperature plasma of a gas that does not have plasma polymerizability at a temperature of 0.01 to 10 Torr.
This is done by exposing the filament fibers to a pressure of . The plasma processing time varies depending on the applied voltage, but generally a range of several seconds to several minutes is sufficient. However, if the treatment time is too short, flickering on the fiber surface cannot be effectively prevented, whereas if the treatment time is too long, the fiber strength and abrasion resistance will decrease. For low-temperature plasma treatment, for example, low frequency or microwave can be used as the discharge frequency band, and direct current can also be used, and the plasma generation mode can be glow discharge, corona discharge, spark discharge, silent discharge, etc. may also be used. Gases that do not have plasma polymerizability include helium, neon, argon, nitrogen, nitrous oxide, nitrogen dioxide, oxygen, air, carbon monoxide, carbon dioxide, hydrogen, chlorine, hydrogen chloride, bromine cyanide, and bromine. Examples include halides such as tin oxide, and sulfides such as sulfur, sulfur dioxide, and hydrogen sulfide, and these gases can be used alone or in combination. The low-temperature plasma treatment may be performed at any stage before or after the dyeing process, and the desired effect can be sufficiently obtained in either process.
Furthermore, in the filament fiber cloth used in the present invention, yarns that have been subjected to these treatments and yarns that have not been treated may be mixed as long as the purpose is not hindered. In addition, other types of threads may be mixed to obtain other effects. [Example] Hereinafter, the present invention will be explained in more detail with reference to Examples. Example 1 A polyester monofilament fiber cloth having the following texture: 35 μ (diameter) x 35 μ (diameter) / 300 pieces/inch x 300 pieces/inch plain weave was dyed under the following conditions. (Dyeing conditions) Dye: Kayalon Polyester manufactured by Nippon Kayaku Co., Ltd.
Black 10% owf Dispersion leveling agent: Nikka Sunsalt manufactured by Nikka Chemical Co., Ltd.
RM-300 PH adjuster: Acetic acid bathing: 1:20 Temperature and time: 60℃→120℃: 20 minutes, 120℃: 40
Min., 120℃→80℃: 15 minutes Reduction cleaning: Hydrosulfite 2g / Caustic soda (30°B'e) 10ml / Nonionic surfactant 2g / (15 minutes at 80℃) Obtained in this way The dyed fabric was then treated with cold plasma. For low-temperature plasma treatment, a 35cm x 35cm square piece of cloth cut from a dyed cloth is set in a predetermined position inside the processing equipment, and the inside of the equipment is temporarily turned off.
After exhausting to 10 ^-4 Torr, Ar gas was introduced through the specified gas introduction pipe to maintain the internal pressure at 0.2 Torr.
13.56MHz) to start the discharge. Here, the output of the high frequency power source was set to 500 W, and the treatment time was varied between 10 seconds and 5 minutes, and plasma was irradiated. Thereafter, a dyed cloth treated with low-temperature plasma was attached to a frame with internal dimensions of 21 cm x 28 cm under slight tension to produce an optical filter, which was placed close to a computer display screen. The results obtained are shown in Table 1.

[Table] As shown in Table 1, if the treatment time is too short, no effect will be produced, and if the treatment time is too long, the uniformity and physical strength of the treatment will be impaired. Example 2 Nylon 6 Monofuillament fibers with the following tissue: 61 μ (diameter) x 61μ (diameter) / 150 / inch x 150 / Inchaire woven, processed in low -temperature plasma as in Example 1 did. However, here, low-temperature plasma was irradiated using oxygen as the gas and with an internal pressure of 2 Torr. Next, a staining treatment was performed under the following conditions. (Dyeing conditions) Dye: Kayakalon Black BGL 5 manufactured by Nippon Kayaku Co., Ltd.
% owf PH adjuster: Acetic acid bathing: 1:20 Temperature and time: 60°C → 92°C: 15 minutes, 92°C: 40 minutes. Using the thus obtained dyed fiber cloth, an optical filter was produced in the same manner as in Example 1. The results obtained are shown in Table 2.

【table】

[Table] Example 3 The polyester monofilament fiber cloth used in Example 1 was subjected to alkali weight loss treatment using a pad steam method. That is, the caustic soda concentration was varied between 10 and 400g/, the squeezing rate was 40%, and the
The fabric was steamed for 1 minute, and then soaped for 10 minutes with hot water at a pH of 8 and a temperature of 90°C to obtain a polyester monofilament fiber fabric with a weight loss rate of 1 to 40%. Next, this product was dyed under the same conditions as in Example 1 to produce an optical filter. The results obtained are shown in Table 3.

〔Effect of the invention〕

The optical filter obtained by the present invention has surface flickering sufficiently and uniformly prevented without deteriorating its physical properties. This makes the characters on the display clearer, effectively suppresses the so-called "flickering" phenomenon, and prevents eye fatigue. In addition, the flicker-prevented filament yarn used in the present invention has antistatic properties.
If the filament yarn has conductivity or is used in combination with yarns having these properties, it can have the effect of preventing the "flicker" phenomenon as well as the effect of shielding electromagnetic waves, thereby preventing mental disorders caused by electromagnetic waves. Exclusion is also possible.

Claims (1)

[Scope of Claims] 1. An optical filter made of filament fiber cloth and facing close to a display screen to prevent light reflection, the optical filter being located at least on the side opposite to the display screen of the filament fiber cloth. 1. An optical filter characterized in that the surface of the fibers is etched to form fine irregularities, and the maximum diameter of the irregularities is 0.01 to 0.5 μ at a maximum frequency. 2. The optical filter according to claim 1, wherein the unevenness is formed by an alkali reduction process or a low-temperature plasma treatment. 3. The optical filter according to claim 1, wherein the filament fibers of the filament fiber cloth have a diameter of 25 to 150μ. 4. The optical filter according to claim 1, wherein the unevenness is present in a number of 1 to 200 per square micron. 5. The optical filter according to claim 1, wherein the filament fiber cloth is made of at least one type of filament fiber selected from natural fibers, inorganic fibers, regenerated fibers, semi-synthetic fibers, and synthetic fibers. 6. The optical filter according to claim 1, wherein the filament fiber is a monofilament fiber.