JPH07261277A - Transmission type projection screen and production therefor - Google Patents

Abstract

PURPOSE:To prevent electrification while maintaining the image quality of a transmission type projection screen. CONSTITUTION:This transmission type projection screen 3 has at least one of lens sheets 1, 2. An aerosol prepared from an aq. soln. or water dispersion liquid containing an antistatic agent and surfactant is deposited on at least one of lens sheets 1, 2 after the sheet is discharged so as to form a thin film 8 having 0.03 to 0.5g/m<2> coating amt. after dried. Since this antistatic film 8 is uniformly formed, an image of high quality without unevenness can be maintained for a long time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the prevention of electrification of transmissive projection screens used in projection televisions.

[0002]

2. Description of the Related Art A screen used in a transmissive projection device for observing projected light through a screen is called a transmissive projection screen. Such a screen diffuses light in a wide range or reduces the brightness of the entire screen. Are required to be uniform or to absorb the external light from the observation side to enhance the contrast of the image. FIG. 1 is a diagram illustrating a transmissive projection screen. In FIG. 1 (A), for example, a Fresnel lens sheet 1 which is a lens sheet formed with a Fresnel lens for condensing light is arranged on the light incident side of a transmissive projection screen, and the light is incident on the light incident surface on the observation side. A lenticular lens sheet 2 with a light-shielding layer, which has a minute convex lens shape for condensing light, has a light output surface near the focal point of each convex lens, and uses an ineffective portion of the light output surface that does not transmit projection light as a light absorbing portion. Type projection screen 3
Are used. Further, as shown in FIG. 1B, in order to further increase light diffusion in the vertical direction and to reduce the visibility of the ghost image with such a configuration, the Fresnel lens sheet 2 may have a horizontal direction on the light incident surface. A transmission type projection screen 5 having a minute horizontal lenticular lens 4 extending in the vertical direction is often used.

In order to meet various requirements for a transmissive screen, the transmissive screen is composed of an assembly of lenses having excellent optical characteristics, and its unit lens is used for displaying a fine image. The size of must be small. Therefore, for example, in the lenticular lens sheet with the light shielding layer, the pitch of the unit lens is 1 mm or less, and in the Fresnel lens sheet, the pitch of the unit lens is about 0.1 mm, and the unit lens has a sharp wedge shape. The pitch of the unit lenses of the horizontal lenticular lens is 0.1 mm or less.

As described above, the transmission type projection screen has a fine and sharp lens shape, and its size is large with a diagonal dimension of 1 m (40 inches) or more. And acrylic resin represented by polymethylmethacrylate, polystyrene resin, polycarbonate resin,
It is manufactured by thermoforming, polymerization molding, ultraviolet curing molding, etc. of transparent resins such as polyester resins and polyvinyl chloride resins.

Further, since the image is observed through the transmissive screen, it is not preferable for dust or dirt to adhere to it in order to obtain a good image. In particular, in a transmissive projection TV shown in FIG. 2 in which a transmissive projection screen and a projector are integrated, the light entrance surface 6 of the transmissive projection screen is inside the TV set 7, so unless the screen is removed, dust and dirt are wiped off. However, since it is impossible for the user to wipe it off, there is a problem that the image quality deteriorates once dust or dirt adheres. Moreover, the material of the screen is a transparent synthetic resin that does not have good conductivity, and it is easy to be charged, and dust, dust, etc. are easily attached. Therefore, in order to prevent the adhesion of dust and dust, it has been considered to mix the antistatic agent in the resin or to apply the antistatic agent to the surface to prevent the static electricity. There is such a problem and it is rarely done in practice.

In order to obtain the antistatic effect by the antistatic agent, it is necessary that a sufficient amount of the antistatic agent be present near the surface of the screen. However, in order for a sufficient amount of antistatic agent to exist near the surface of the screen, it is necessary to mix several percent or more of the antistatic agent into the synthetic resin used as the raw material for the screen. If the amount of the antistatic agent is increased, problems such as deterioration of transparency of the synthetic resin, which is required to be transparent and non-colored, cloudiness, and coloring occur. Particularly in a hard transparent resin material such as an acrylic resin, it is generally difficult to transfer the antistatic agent to the surface layer at room temperature, so that the antistatic performance cannot be obtained or the antistatic agent is contained in a large amount. As a result, the harmful effect becomes remarkable.

Further, in the method of applying the antistatic agent to the surface, coating unevenness occurs when the film thickness of the antistatic layer is not uniform, and when the film thickness is thick, the surface becomes sticky, fingerprints, stains and the like. Etc. are conspicuous and cause a problem in appearance. Further, the widely used antistatic agent is a solution using alcohol as a solvent, and has a high surface tension, and it is difficult to form a film in which the antistatic agent is evenly spread. Then, the coating is carried out by dipping, a coating method using a roll or cloth, etc., but since the surface of the screen sheet has a lens shape consisting of fine irregularities, it is very difficult to form the antistatic layer uniformly over the entire screen sheet. is there. In addition, there are problems that the coating equipment is large, mass productivity is low, and cost is high.The method of spraying the coating liquid is high in mass productivity and advantageous in cost, but the mist of the antistatic agent is a screen. It adheres intensively to the charged parts on the surface of the sheet, impairing the uniformity of the film thickness. Furthermore, it is very difficult to set the solution concentration in order to form a uniform and thin antistatic layer after evaporation of the solvent, but this setting is extremely difficult. A uniform thin antistatic layer cannot be formed on the surface, and the antistatic effect cannot be obtained, and in addition, the unevenness of the antistatic effect depending on the position causes dust and dirt to be unevenly attached and appear as unevenness on the image. The problem arises.

[0008]

DISCLOSURE OF THE INVENTION The present invention does not deteriorate the properties such as transparency and coloring that occur when a large amount of an antistatic agent is added to a resin in a transmission type projection screen, and the screen surface is not deteriorated. An object of the present invention is to provide a transmissive projection screen in which deterioration of image display characteristics due to coating unevenness occurring during application of an antistatic agent is prevented and dust and dirt are less likely to adhere.

[0009]

SUMMARY OF THE INVENTION The present invention comprises at least one
In a transmission type projection screen having a single lens sheet, a thin film comprising an antistatic agent and a surfactant is formed on at least one surface of the lens sheet in an amount of 0.03 to 0.5 g / m ^2.
Is a transmissive projection screen formed with a coating amount of. Further, it is a transmission projection screen in which the surfactant is a fluorine-based surfactant.

Further, in the method of manufacturing a transmission type projection screen having at least one lens sheet, an aerosol formed from an aqueous solution or dispersion containing an antistatic agent and a surfactant is used for at least one of the lens sheets.
It is a method of manufacturing a transmission type projection screen attached to one surface. This is a method for producing a transmission projection screen in which an aerosol is attached after the amount of charge on the surface to which the aerosol is attached is set to 3 kV or less. Further, it is a method for producing a transmission type projection screen in which the concentrations of an antistatic agent and a surfactant in an aerosol-forming aqueous solution or aqueous dispersion are 0.5 to 3% by weight and 0.01 to 1% by weight, respectively. . Furthermore, it is a method for producing a transmissive screen in which the surfactant is a fluorine-based surfactant.

[0011]

In the present invention, even a thin projection surface such as a transmissive projection screen can be formed with a uniform thin antistatic film easily with good mass productivity and at a low cost. The type projection screen does not easily get dust and dirt, and even if it does, it is thin and uniform so that good image quality can be displayed for a long time.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the drawings. FIG. 3 is a diagram for explaining an embodiment of a transmission type projection screen 1 which has been subjected to an antistatic treatment according to the present invention. FIG. 3 (A) shows
In a transmission type projection screen in which a Fresnel lens sheet is arranged on the light incident side and a lenticular lens sheet with a light shielding layer is arranged on the observation side, a coating amount of 0.03 to 0.5 g / m ² is applied on the light incident side of the Fresnel lens sheet. An antistatic film 8 which is a thin film composed of an antistatic agent and a surfactant in a certain range is formed. FIG. 3B shows a transmission in which a lenticular lens sheet with a light-shielding layer is arranged on the observation side on the light-incident side of a Fresnel lens sheet having a horizontal lenticular lens 4 on the light-incident surface, which horizontally diffuses light in the vertical direction. In the die projection screen, the antistatic film 8 of the present invention is formed on the light entrance surface of the Fresnel lens sheet, that is, on the horizontal lenticular lens 4.

When the antistatic film of the present invention is formed on a transmissive projection screen, it has an antistatic effect for a long period of time, dust and dirt hardly adhere, and even if it adheres, it is thin and uniform, so that good image quality can be obtained. In particular, in the case of a transmissive projection television in which a transmissive projection screen and a projector are integrated, stains on the light entrance surface of the transmissive projection screen cannot be wiped off because they are inside the device, and therefore, as shown in FIG. It can be said that in order to obtain a good image quality, it is necessary to form the antistatic film of the present invention on the light-entering surface of the mold projection screen to prevent dust and dirt from adhering.

FIG. 4 is a diagram for explaining another embodiment,
FIG. 4A shows a case where the antistatic film 8 of the present invention is formed on the light incident surface and the light incident surface 9 of the Fresnel lens sheet of the transmissive projection screen and the light incident surface 10 of the lenticular lens sheet with the light shielding layer. . In this way, when assembling a transmissive projection screen by assembling a Fresnel lens sheet and a lenticular lens sheet with a light-shielding layer around the periphery or assembling a transmissive projection TV, dust and dirt are left between the screen sheets. It is not necessary to remove dust and dirt that adheres to the transmissive projection screen at the time of assembly without adhering, and a device having excellent image display characteristics can be manufactured. In addition, FIG.
When the antistatic film 8 of the present invention is formed not only on the light incident surface but also on the light outgoing surface 11 of the lenticular lens with a light shielding layer, that is, the antistatic film 8 of the present invention is formed on all surfaces of the screen sheet. Indicate the case. This is useful because dust and dirt are less likely to adhere to the observation-side surface of the transmissive projection screen and the frequency of touching the screen for cleaning the screen is reduced, and the risk of scratching the screen is reduced.

FIG. 5 shows a transparent substrate 12 for protecting the lenticular lens sheet with the light shielding layer on the observation side of the Fresnel lens sheet and the lenticular lens sheet with the light shielding layer.
The case where the antistatic film of the present invention is formed on all the surfaces of the transmissive projection screen in which is arranged is shown. In this way, a transmissive projection screen is composed of the screen sheet and the transparent substrate,
Even when the antistatic film of the present invention is formed on the surface of each sheet, the effect and usefulness of each antistatic are the same as those described in FIGS. In other words, it is natural that good image quality can be obtained without dust and dirt adhering, but in addition to that, the antistatic property between the surfaces of the sheets enhances the effect when assembling a transmissive projection screen or a transmissive projection TV. You can Furthermore, the antistatic charge on the viewing side of the screen also prevents scratches. Further, the antistatic effect of the present invention as described above is the same in the transmission type projection screens having various configurations. For example, a transmissive projection screen with a single element that has a Fresnel lens surface on the light input side and a vertical lenticular lens that extends vertically on the light output side, a horizontal linear Fresnel lens that collects light in the vertical direction on the light input side, observation Vertical linear Fresnel lens that horizontally collects light on the side, a transmission projection screen with three elements with a lenticular lens sheet with a light blocking layer on the most viewing side, Fresnel lens sheet on the light entering side, light blocking layer on the viewing side The attached lenticular lens sheet, a transmissive projection screen composed of three horizontal lenticular lenses that diffuse light vertically to the most observing side, and a transparent substrate disposed on the light incident side can be given as examples.

As the transmissive projection screen of the present invention, a transparent resin such as an acrylic resin represented by polymethylmethacrylate, a polystyrene resin, a polycarbonate resin, a polyester resin, or a polyvinyl chloride resin is used. However, a polymethylmethacrylate resin that has particularly excellent optical properties and mechanical properties and is easy to mold is preferable. Further, the antistatic agent used in the present invention is an antistatic agent usually used for antistatic of synthetic resins, and is a cation such as lauryltrimethylammonium chloride, stearyltrimethylammonium chloride, lauryldiethanolamine, stearylamine hydrochloride. Antistatic agent, diethanolamine alkyl phosphate, potassium alkyl phosphate,
There are anionic antistatic agents such as alkylbenzene sulfonates, nonionic antistatic agents such as polyethylene glycol monooleate and polyoxyethylene sorbitan monooleate, and among these, cationic antistatic agents are preferably used. It

In the present invention, the aqueous solution or dispersion containing the antistatic agent as described above is applied onto a transmission projection screen and dried to form a thin film. When the surface tension of the aqueous solution or dispersion containing the antistatic agent is higher than the surface tension of the transmissive screen surface to be coated, the aqueous solution or dispersion does not spread well on the transmissive screen surface and a thin uniform film is formed. Therefore, it is necessary to make the surface tension of the aqueous solution or the aqueous dispersion smaller than the surface tension of the surface to be coated. The inventors of the present invention have earnestly studied and found that the surface tension of this aqueous solution or dispersion is 30 dy when applied to a transparent resin used for a transmission screen.
It has been found that it is preferable to set the ne / cm (25 ° C.) or less.

The surface tension of the antistatic agent coating liquid is set to 30 dy.
In order to reduce the ne / cm (25 ° C.) or less, it is preferable to add a surface active agent, and particularly a fluorine type surface active agent having a high effect of lowering the surface tension is suitable. For example, fluoroalkylcarboxylic acid, perfluoro Alkyl carboxylic acids, fluoroalkyl phosphates, perfluoroalkyl phosphates, polyoxyethyl perfluoroalkyl phosphates, perfluoroalkyl sulfates, perfluoroalkyl quaternary ammonium and other alkali metal salts, alkaline earth metal salts, Perfluoroalkylsulfonamide derivatives, perfluoroalkylamines, perfluoroalkylimidazolidines, perfluoroalkylbetaines, polyoxyethylene perfluoroalkyl ethers, polyoxyethylene perfluoroalkylphenones , Polyoxyethylene perfluoroalkyl amine, perfluoroalkyl carboxylic acid sorbitan ester. Of these fluorine-based surfactants, compounds having 6 to 22 carbon atoms are particularly preferable.

Specific examples of such a surfactant include:
Sodium 16-fluorohexadecylcarboxylate, perfluorooctylcarboxylic acid-N, N-diethanolamine, sodium perfluorooctyl phosphate, sodium perfluorodecyl phosphate, polyoxyethylene perfluorooctyl phosphate sodium, N-polyoxyethylene -N-ethyl perfluorooctyl sulfonamide, N, N-di (polyoxyethylene) perfluorooctyl sulfonamide, N-
Polyoxyethylene-N-butylperfluorodecylsulfonamide, N-polyoxyethylene-N-ethylperfluorooctadecylsulfonamide, perfluorododecyltrimethylammonium salt, perfluorooctadecylbetaine, polyoxyethylene perfluorooctyl ether, polyoxy Examples thereof include ethylene perfluorooctadecenyl ether, polyoxyethylene perfluorohexylamine, and perfluorododecylcarboxylic acid sorbitan ester, which may be used alone or in combination of two or more. In the present invention, when the coating amount of the antistatic film is less than 0.03 g / m ² , it is difficult to make the film thickness uniform when forming a thin film, a sufficient antistatic effect cannot be obtained, and the antistatic effect is deteriorated. If the coating amount is more than 0.1 g / m ² , the thin film becomes non-uniform, and when used as a transmission type projection screen, it looks uneven, which is not preferable.

Next, the method for producing the antistatic film of the present invention will be described. An aqueous solution or an aqueous dispersion containing an antistatic agent and a surfactant is applied to at least one surface of the transmissive projection screen, and at this time, it is evenly applied to the surface of the transmissive projection screen having fine irregularities on the surface. In order to achieve this, it is preferable to apply this aqueous solution or aqueous dispersion by an aerosol spraying method in which it is aerosolized and attached to the surface. In particular, for the generation of aerosol, it is desirable to use a method using an ultrasonic oscillator that can obtain a uniform and small aerosol particle. The concentration of the antistatic agent and the surfactant in the aqueous solution or the aqueous dispersion is 0.5 to 5% by weight, and the concentration of the surfactant is 0.01 in order to form a good thin film. It is desirable that the content be ˜1 wt%, and even if it is added more than this, no further effect can be obtained. Further, the coating amount is 0.0 as a coating film after drying.
It is preferable to apply so as to obtain 3 to 0.5 g / m ² .

When an aqueous solution or dispersion containing the antistatic agent and the surface-preventing agent of the present invention is applied to a screen sheet by an aerosol spraying method, even if the aerosol particles are sufficiently small and the particle size is uniform, the particles are uniform. The coating film may not be formed. The present inventors have diligently studied this problem,
It has been found that the amount of charge on the sheet of screen to be applied has an adverse effect. If the charge amount is large, the application with the aerosol becomes non-uniform, so it is preferable to reduce the charge amount, and it is preferable to set the charge amount to 3 kV or less. In order to reduce the charge amount, it is desirable to charge the screen sheet in advance with a charge-removing brush or a charge-removing bar such as Tordesat (made by Idemitsu Petrochemical Co., Ltd.) to reduce the charge amount to 3 kV or less before coating. Next, a thin film is formed by drying the applied screen sheet. For drying, a commonly used method can be applied. For example, warm air may be blown or air drying may be performed at room temperature.

Example 1 A Fresnel lens shape having a length of 640 mm, a width of 840 mm and a thickness of 3 mm, a focal length of 800 mm on the light exit side and a pitch of 0.11 mm, a pitch of 0.08 mm on the light entrance side, and a curved surface having a radius of 0.12 mm. A Fresnel lens sheet made of polymethylmethacrylate resin (manufactured by Sumipex Sumitomo Chemical Co., Ltd.) having a horizontal lenticular lens shape, which is a part, and having a charge amount of 4 kV, and an ultrasonic oscillation type aerosol spray device (MDC treatment device (Tokyo Copal (Manufactured by Kagaku Co., Ltd.) is used, and the light is received under a fine mist of an aqueous solution containing 2% by weight of lauryltrimethylammonium chloride and 0.2% by weight of a fluorine-based nonionic surfactant (Surflon S Asahi Glass). Expose the surface for 5 seconds, then 40 ° C
After drying with warm air, the coating film after drying is 0.0
A Fresnel lens sheet having a thin film of 4 g / m ² was obtained. The surface specific resistance of the obtained Fresnel lens sheet was measured by the method specified in JIS K6911.

Also, this Fresnel lens sheet and a lenticular lens sheet with a light shielding layer (pitch 0.84 mm, horizontal half-value angle 40 °, vertical half-value angle 4 °, gain 9) are combined and mounted on a 40-inch transmissive projection television. The image quality was evaluated by measuring the contrast ratio, measuring the image degree using a test pattern, and visually inspecting a white screen.
In addition, the Fresnel lens sheet was left in a laboratory under a normal environment for one month, and the same image quality was evaluated. The results are shown in Table 1. ○ No dust or dirt is attached and unevenness is not visible. X indicates unevenness due to uneven adhesion of dust and dirt. Δ indicates that the thickness of the thin film is non-uniform and unevenness is visible.

[0024]

[Table 1]

Example 2 Aerosol atomization was carried out in the same manner as in Example 1 except that the Fresnel lens sheet was neutralized and applied in a state where the charge amount was 2 kV, and Fresnel having a thin film with an application amount of 0.04 g / m ^{2 was} applied. I got a lens sheet. The Fresnel lens sheet obtained was evaluated in the same manner as in Example 1, and the results shown in Table 1 were obtained.

Example 3 A Fresnel lens sheet having a thin coating film of 0.45 g / m ² after drying was obtained in the same manner as in Example 2 except that the treatment time of aerosol spraying was 20 seconds. The Fresnel lens sheet obtained was evaluated in the same manner as in Example 1, and the results shown in Table 1 were obtained. Comparative Example 1 A Fresnel lens sheet having a thin film with a coating amount of 0.02 g / m ² was obtained in the same manner as in Example 2 except that the treatment time of aerosol spraying was 3 seconds. The Fresnel lens sheet obtained was evaluated in the same manner as in Example 1, and the results shown in Table 1 were obtained.

Comparative Example 2 A Fresnel lens sheet having a thin film with a coating amount of 0.55 g / m ² was obtained in the same manner as in Example 2 except that the aerosol spraying treatment time was 24 seconds. The Fresnel lens sheet obtained was evaluated in the same manner as in Example 1, and the results shown in Table 1 were obtained.

Comparative Example 3 Cationic antistatic agent (electrostripper QN
2% by weight of Kao) is soaked in a cloth, and a Fresnel lens sheet having the same outer dimensions, lens shape and material as the one used in Example 1 is coated with the light-incident surface and then air-dried to Fresnel lens. Got the sheet. The coating amount at this time was 0.52 g / m ² . The Fresnel lens sheet obtained was evaluated in the same manner as in Example 1, and the results shown in Table 1 were obtained.

In the present invention, the surface on which the antistatic film is formed and the aerosol spraying device used are not limited to the examples, and various modifications can be made without departing from the technical idea of the present invention. is there

[0030]

According to the present invention, a thin and uniform antistatic film is formed on a transmissive projection screen so that the transmissivity of the screen is not lowered or clouded and the durability is good and the effect is high. Antistatic performance can be imparted. Therefore, the transmissive projection screen of the present invention can display a good image for a long period of time.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a transmissive projection screen.

FIG. 2 is a diagram illustrating a projection television equipped with a transmissive projection screen.

FIG. 3 is a diagram illustrating one embodiment of a transmission type projection screen of the present invention.

FIG. 4 is a diagram illustrating an example of a transmission type projection screen of the present invention.

FIG. 5 is a diagram illustrating one embodiment of a transmission type projection screen of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Fresnel lens sheet, 2 ... Lenticular lens sheet with a light shielding layer, 3 ... Transmission type projection screen, 4 ... Horizontal lenticular lens, 5 ... Transmission type projection screen, 6
... Fresnel lens light-entering surface, 7 ... Transmission type projection television, 8 ... Antistatic thin film of the present invention, 9 ... Fresnel lens light-emitting surface, 10 ... Lenticular lens light-receiving surface with light-shielding layer, 11 ... Lenticular lens light-emitting surface with light-shielding layer. , 12
… Transparent substrate, 13… Projector, 14… Mirror

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Hideki Miyata 1-1-1 Ichigaya-Kagacho, Shinjuku-ku, Tokyo Within Dai Nippon Printing Co., Ltd. (72) Inventor Hachiro Yamada 2--10-1 Tsukahara, Takatsuki-shi, Osaka No. Sumitomo Chemical Industry Co., Ltd.

Claims (6)

[Claims] 1. A transmissive projection screen having at least one lens sheet, wherein a thin film comprising an antistatic agent and a surfactant is applied in an amount of 0.03 to 0.5 g / m ^{2 on} at least one surface of the lens sheet. A transmissive projection screen characterized by being formed in a quantity. 2. The transmission projection screen according to claim 1, wherein the surfactant is a fluorinated surfactant. 3. A method of manufacturing a transmission projection screen having at least one lens sheet, wherein an aerosol formed from an aqueous solution or dispersion containing an antistatic agent and a surfactant is applied to at least one surface of the lens sheet. A method for manufacturing a transmissive projection screen, characterized in that it is attached. 4. The amount of charge on the surface to which the aerosol is attached is 3
4. The method for manufacturing a transmission type projection screen according to claim 3, wherein the aerosol is attached after the voltage is set to kV or less. 5. The concentration of an antistatic agent or a surfactant in an aqueous solution or an aqueous dispersion for forming an aerosol is 0.
The method for manufacturing a transmission type projection screen according to claim 3 or 4, wherein the content is 5 to 3% by weight and 0.01 to 1% by weight. 6. The method for producing a transmissive screen according to claim 3, wherein the surfactant is a fluorinated surfactant.