JPWO2010106999A1 - Display device assembly tape substrate, display device assembly pressure-sensitive adhesive sheet using the same, and display module unit - Google Patents

Abstract

The present invention provides a tape substrate for assembling a display device having excellent light shielding properties and light reflecting properties. In the tape substrate A for assembling the display device of the present invention, the light shielding layers 2 and 2 are laminated and integrated on both surfaces of the substrate film 1, and the light reflecting layer 3 is laminated and integrated on one of the light shielding layers 2. Since each of the light shielding layers 2 and 2 is formed separately via the base film 1, even if pinholes are formed in each light shielding layer 2, the pinholes are extremely Since the hole has a small diameter, there is almost no possibility that pinholes formed in each light shielding layer 2 overlap each other, and light can be surely blocked by the two light shielding layers 2 and 2.

Description

  The present invention relates to a tape substrate for assembling a display device, a pressure-sensitive adhesive sheet for assembling a display device using the same, and a display module unit.

  In recent years, liquid crystal display devices are often used as display devices for electronic devices such as mobile phones and electronic notebooks. As a liquid crystal display device used in such a small electronic device, a sidelight type backlight type liquid crystal display device is employed.

  The above-mentioned sidelight type backlight type liquid crystal display device is generally arranged in a synthetic resin backlight casing after optical films such as a reflection sheet, a light guide plate, a diffusion sheet, and a prism sheet are laminated. A liquid crystal display panel is laminated and integrated on the laminated optical film via a display device assembly tape base material, and a lamp reflector is provided on the side of the light guide plate to provide an LED (Light Emitting Diode). ) Etc. are disposed.

  The tape base material for assembling the display device is a liquid crystal display panel that reflects light from the light source and has a light shielding property for preventing deterioration of the appearance of the liquid crystal display surface due to light entering the outer peripheral portion of the liquid crystal display panel. It is necessary to have both light reflectivity for efficiently guiding light.

  As such a tape base material for assembling a display device, Patent Document 1 discloses (a) a combination of light reflectivity and light shielding properties used by adhering between an LCD panel of an LCD module and a backlight housing. And (b) a support formed by laminating a light reflection layer and a light shielding layer, and an adhesive layer provided on at least one surface of the support, and (c) the light reflection An adhesive tape comprising a biaxially stretched white resin film in which a layer is kneaded with a white colorant having a thickness of 10 to 30 μm and a tensile strength of 10.0 N / 10 mm or more, and has a total thickness of 20 to 100 μm. It is disclosed.

  The light-shielding layer of the adhesive tape is formed by applying black ink on a biaxially stretched white resin film and drying, and it is described that it is preferable to laminate 2 to 4 layers to prevent pinholes. (Paragraph number [0034]).

  In order to laminate 2 to 4 light shielding layers on the white resin film, black ink is applied on the white resin film and dried, and then black ink is applied on the black ink coating and dried.

  However, although the black ink is applied on the white resin film and then dried, the black ink applied on the white resin film is completely dried before the next black ink is applied. Since doing so reduces the production efficiency, before the black ink already applied onto the white resin film is completely dried, the next black ink is applied onto the coating film.

  On the other hand, black ink contains inorganic particles such as silicon particles as an anti-blocking agent, and it is considered that these inorganic particles may cause pinholes in the light shielding layer. As described above, when the black ink applied on the white resin film is not completely dried and the next black ink is applied repeatedly, the inorganic particles contained in the black ink are overcoated. Crossing in the thickness direction through a plurality of coating layers that are not completely dried, and as a result, even if a plurality of light shielding layers are stacked, a pinhole is formed across the light shielding layer in the thickness direction However, there is a problem that sufficient light shielding properties cannot be secured.

  Therefore, the more the number of times the black ink is overcoated on the white resin film, the less likely the problem of pinholes in the light shielding layer will be. However, the thicker the light shielding layer, the greater the thickness of the adhesive tape. As a result, the thickness of the display device of the electronic device is reduced, and the desire to reduce the thickness of the display device of the electronic device is impaired.

  Moreover, when the colored pigment contained in the black ink forming the light shielding layer has conductivity, the conductivity of the light shielding layer rapidly increases when the thickness of the light shielding layer exceeds a certain thickness. As a result, it has been pointed out that a current flows through the light shielding layer, and this current causes a malfunction of the control device of the display panel of the display device.

JP 2004-156015 A

  The present invention has excellent light-shielding properties and light-reflecting properties, and the display panel control device does not malfunction due to the current flowing in the light-shielding layer, and can reliably maintain the display performance of the display panel. Provided are a display device assembly tape substrate, a display device assembly pressure-sensitive adhesive sheet using the display device assembly tape substrate, and a display module unit.

  The tape substrate for assembling the display device according to the present invention includes carbon black produced by a furnace method as a black colorant and a light shielding layer having a thickness of 1 to 5 μm laminated and integrated on both surfaces of a substrate film. In addition, the light reflecting layer is laminated and integrated on any one of the light shielding layers.

  The display module unit according to the present invention includes a frame-like backlight housing having a panel mounting step formed on the inner peripheral surface, and a display device assembly mounted on the panel mounting step. A pressure-sensitive adhesive sheet, a light-shielding layer having a thickness of 1 to 5 μm containing a base film, carbon black laminated and integrated on both surfaces of the base film and manufactured by a furnace method as a black colorant, and the light shielding A display device assembly pressure-sensitive adhesive sheet including a light reflecting layer laminated and integrated on any one of the light-shielding layers, a display panel disposed on the display device assembly pressure-sensitive adhesive sheet, and the backlight housing. And a plurality of optical films disposed in a laminated state in the body.

  In the tape substrate for assembling the display device of the present invention, the light shielding layer is laminated and integrated on both surfaces of the substrate film, and the light reflecting layer is laminated and integrated on one of the light shielding layers. The light shielding layer is formed separately through the base film, and even if pinholes are formed in each light shielding layer, the pinholes are extremely small diameter holes, so the pinholes formed in each light shielding layer There is almost no possibility of overlapping each other, and light can be reliably blocked by the two light shielding layers.

  The light-shielding layer contains carbon black produced by the furnace method as a black colorant, that is, furnace black, and the light-shielding layer has excellent light-shielding properties and is incident on the tape substrate for assembling the display device. The light can be blocked more reliably.

  Furthermore, in addition to reducing the conductivity of the light shielding layer by using furnace black as the black colorant contained in the light shielding layer, the thickness of the light shielding layer is 1 to 5 μm, so that the resistance of the light shielding layer It is possible to prevent a current from flowing through the light shielding layer by setting the value to 500 MΩ or more. Therefore, it is possible to prevent malfunction of the display panel control device due to current flowing through the light shielding layer.

It is the longitudinal cross-sectional view which showed the tape base material for display apparatus assembly of this invention. It is the longitudinal cross-sectional view which showed the adhesive sheet for a display apparatus assembly of this invention. It is the longitudinal cross-sectional view which showed another example of the adhesive sheet for a display apparatus assembly of this invention. It is the longitudinal cross-sectional view which showed another example of the adhesive sheet for a display apparatus assembly of this invention. It is the longitudinal exploded view which showed the display module unit of this invention. It is the disassembled perspective view which showed the display module unit of this invention. It is the schematic diagram which showed the point which measures the electroconductivity of the light shielding layer of the tape base material for display apparatus assembly of this invention.

  An example of the tape base material for assembling the display device of the present invention will be described with reference to the drawings. The tape base material A for assembling the display device of the present invention has the light shielding layers 2 and 2 laminated and integrated on both surfaces of the base film 1 and the light reflecting layer 3 laminated and integrated on one of the light shielding layers 2. It is characterized by that. The shape of the tape base material A for assembling the display device is not particularly limited, but in the following description, a case where it is formed in a frame shape will be described as an example.

  The synthetic resin constituting the base film 1 of the tape base material A for assembling the display device is not particularly limited as long as it is conventionally used as a tape base material. For example, a polyvinyl chloride film, a polypropylene film , Polyethylene film, polyester film, polycarbonate film, polyimide film, polystyrene film, cellophane and the like. Polyester film and polypropylene film are preferable, and polyethylene terephthalate film is more preferable.

  When the thickness of the base film 1 is large, the thickness of the obtained tape base material for assembling the display device is increased, and therefore, the thickness is preferably 10 μm or less. When the thickness of the base film 1 is thin, the strength of the display device assembly tape base material is reduced, and the display device assembly tape base material is likely to wrinkle during use. 1 μm or more is preferable, 3 μm or more is more preferable, and 4 μm or more is particularly preferable. In addition, the thickness of the base film 1 cut | disconnects the tape base material for a display apparatus assembly in the thickness direction in arbitrary places, observes the cut surface with an electron microscope, and is the base material film of arbitrary 5 places. The arithmetic average value of thickness is used.

  And it is preferable that the base film 1 does not contain a powdered colored pigment, and by not containing the powdered colored pigment in this way, the base film can be made thin, As a result, it is possible to reduce the thickness of the display device assembling tape base material. The powdered colored pigment is not particularly limited as long as it is powdered at room temperature, white pigments such as titanium dioxide, barium sulfate, zinc white, lead white, carbon black, acetylene black, pine smoke, Examples thereof include black pigments such as graphite and other various pigments.

  In particular, by not containing a powdered colored pigment in the base film 1, it becomes possible to perform a high-magnification stretching process without causing cracks in the base film, and further reducing the thickness and strength of the base film. Can be improved.

  As shown in FIG. 1, light shielding layers 2 are laminated and integrated on both surfaces of the base film 1. The light shielding layer 2 is carbon black produced by a furnace method (hereinafter referred to as “furnace black”) as a black colorant in order to block light and prevent light from being transmitted to the base film 1 side through the light shielding layer 2. Is included).

  The light shielding layer 2 can impart excellent light shielding properties to the light shielding layer 2 while suppressing the conductivity of the light shielding layer 2 by containing carbon black produced by the furnace method as a black colorant. When used to integrate the display panel and the backlight housing, it prevents light leakage from the backlight housing and prevents malfunction of the display panel control device, thereby improving the display performance of the display panel. It can maintain reliably and the outstanding visibility and display property of a display apparatus can be achieved.

  If the average particle size of the black colorant (furnace black) is small, the black ink may not be easily handled, and if the average particle size is large, the surface roughness of the light-shielding layer becomes large and it is integrated with the adhesive layer. Is preferably in the range of 0.01 to 0.5 μm. In addition, the average particle diameter of a black coloring agent says the calculated average diameter calculated | required by observing with an electron microscope.

  In order to form the light-shielding layer 2, a black ink containing furnace black as a black colorant may be applied and dried on the base film 1. Under the present circumstances, it is preferable to perform the process of apply | coating and drying the said ink on the base film 1 over multiple times. That is, the process of applying and drying the black ink may be repeated a plurality of times, and a plurality of light shielding base layers may be laminated and integrated to form the light shielding layer 2. In this way, by integrating multiple layers of light shielding base layers, even if a pinhole is formed in one light shielding base layer, the pinhole has an extremely small diameter, so that the pinhole has another light shielding property. Since there is no overlap with the pinhole formed in the base layer, the pinhole formed in the light shielding base layer can be surely shielded by another light shielding base layer, and the light shielding property of the light shielding layer 2 is more reliable. can do. For applying the ink, general-purpose means such as gravure printing, flexographic printing, and offset printing may be used.

  In addition, as described above, when black ink is applied to both surfaces of the base film 1, the compatibility between the base film and the black ink is low, that is, the wettability (affinity) of the base film is low. When the black ink is applied to the surface of the base film 1, the black ink is not uniformly applied onto the base film 1, and in particular, the black ink is thinly applied without the black ink being uniformly applied. If carbon black is present in the part, the binder is not supplied smoothly around the carbon black. As a result, a fine part where black ink is not partially applied is generated. Is assumed to be a pinhole.

  Therefore, in order to apply the black ink as uniformly as possible to the surface of the base film 1, corona discharge treatment has been applied to both sides of the base film 1 in advance to improve the wettability of both sides of the base film 1. And it is preferable to form the light shielding layer 2 (light shielding base layer) by apply | coating black ink on both surfaces of the base film 1. FIG. The corona discharge treatment is preferably performed so that the surface tension of the base film 1 is 40 mN / m or more.

  The black ink containing a black colorant (furnace black) preferably contains a black colorant (furnace black), a binder, and a solvent. The binder is not particularly limited, and those conventionally used in inks are used, and examples include polyurethane resins, phenol resins, epoxy resins, urea melamine resins, polymethyl methacrylate, and the like. A polyurethane resin is preferred.

  As the binder, those having a halogen element content of 50 ppm or less such as chlorine, bromine, fluorine and iodine are preferable. This is because if the binder contains a large amount of halogen element, a gas caused by the halogen element is generated during use of the display device, and this gas causes the display performance of the display device to deteriorate. Alternatively, harmful gas may be generated during incineration.

  The amount of halogen element in the binder can be measured by emission spectroscopic analysis. The emission spectroscopic analysis method is a measurement method in which atoms are excited by a plasma light source to emit light, the emitted light is dispersed by a diffraction grating or the like, and a so-called atomic spectrum is obtained to identify a contained element. A measuring device commercially available from Shimadzu Corporation under the trade name “PDA series” can be used.

  It does not specifically limit as said solvent, What is necessary is just to select suitably according to the kind of binder.

  If the content of the black colorant (furnace black) in the black ink is large, the electrical insulation when used in the display device may be lowered. Therefore, it is preferably less than 12% by weight in the ink. .

  Inks containing a black colorant (furnace black) are commercially available from Dainippon Ink Chemical Co., Ltd. under the trade name “Univia A-300” and from Teikoku Ink Manufacturing Co., Ltd. under the trade name “EGS-911 Black”. Yes.

The light shielding layer preferably has an L ^* representing 25 ± 10 in the L ^* a ^* b ^* color system specified by JIS Z8729.

  If the content of the black colorant (furnace black) in the light-shielding layer 2 is small, the light-shielding property of the light-shielding layer is lowered, and when used to integrate the display panel and the backlight housing, the backlight Light leakage from the housing may occur, and the visibility of the display device may be lowered. If it is frequently, the electrical insulation when used in the display device may be lowered, so 15 to 70% by weight is preferable. .

  When the thickness of the light shielding layer 2 is large, the thickness of the tape base material for assembling the display device is increased, and when the colored pigment having conductivity is contained in the light shielding layer, the conductivity of the light shielding layer is increased. It causes malfunction of the panel control device. Moreover, when the thickness of the light shielding layer 2 is thin, the light shielding performance is deteriorated. Therefore, the thickness of the light shielding layer 2 is limited to 1 to 5 μm, and preferably 2 to 4 μm. In addition, the thickness of the light shielding layer is obtained by cutting the tape base material for assembling the display device at an arbitrary position in the thickness direction, observing the cut surface with an electron microscope, and measuring the thickness of the light shielding layer 2 at any five positions. Use the arithmetic mean value.

  Further, if the total thickness of the light shielding layers 2 and 2 laminated and integrated on both surfaces of the base film 1 is thin, the light shielding performance may be deteriorated. If it is thick, the conductivity of the light shielding layer is increased and the display panel is increased. 2 μm or more is preferable, 2 to 10 μm is more preferable, and 4 to 8 μm is more preferable.

  In this way, the light shielding layers 2 and 2 are laminated and integrated on both surfaces of the base film 1, and the pinhole formed in the light shielding layer 2 laminated and integrated on one surface of the base film 1, and the base material The pin hole formed in the light-shielding layer 2 laminated and integrated on the other surface of the film 1 has a very small diameter and is very unlikely to overlap. A has excellent light shielding properties.

  The light shielding layers 2 and 2 are formed separately. As described above, even if a pinhole is formed in one of the light shielding layers 2, the light transmitted through the pinhole is transmitted through the other light shielding layer 2. Since blocking is performed, it is not necessary to increase the thickness of the light shielding layer 2 more than necessary in order to prevent the formation of pinholes. Therefore, the thickness of the display device assembly tape substrate A can be reduced, and the thickness accuracy of each of the light shielding layers 2 and 2 can be improved, and the quality of the display device assembly tape substrate A is made uniform. be able to.

  Furthermore, since the thickness of the light shielding layer 2 can be reduced, even if a conductive colored pigment is contained in the light shielding layer 2, an increase in the conductivity of the light shielding layer 2 due to the conductive colored pigment is prevented. It is possible to prevent electricity from flowing through the light shielding layer 2. As a result, the display panel control device does not malfunction due to the current flowing through the light shielding layer 2, and the display performance of the display panel can be reliably maintained.

  Further, as described above, the light shielding layer 2 is usually formed by applying and drying black ink on the surface of the base film 1, but when applying the black ink on the surface of the base film 1, The black ink applied on the film may be partially repelled, and the black ink is insufficiently applied on the base film in this portion, and pinholes are formed in the light shielding layer. Therefore, the pinhole formed in the lower light-shielding layer is concealed by the light-shielding layer formed on the upper side by repeating the process of applying the black ink on the base film and drying to form the light-shielding layer multiple times. It is possible to do. However, the black ink for forming the upper light-shielding layer is likely to be repelled even if black ink is applied again to the part where the black ink was repelled when forming the lower light-shielding layer. There is a high possibility that pinholes are also formed in the same part of the light shielding layer and the pinholes cannot be hidden.

  On the other hand, in the tape substrate A for assembling the display device of the present invention, since the light shielding layers 2 and 2 are separately formed on both surfaces of the substrate film 1, black ink is separately applied to each of both surfaces of the substrate film. ing. Therefore, in the black ink applied on both surfaces of the base film, the possibility that the portions repelled by the base film are the same is very low. Therefore, the position where the pinhole is formed in one light-shielding layer 2 and the position where the pinhole is formed in the other light-shielding layer 2 hardly overlap each other, and the pinhole formed in one light-shielding layer 2 Is reliably hidden by the pinhole formed in the other light shielding layer 2. Therefore, the tape base material A for assembling the display device of the present invention has excellent light shielding properties.

  In addition, the light shielding layers 2 and 2 laminated and integrated on both surfaces of the base film 1 of the tape base material A for assembling the display device of the present invention do not need to have the same configuration. Different configurations may be adopted.

  Further, the light reflecting layer 3 is laminated and integrated on one of the light shielding layers 2 of the tape base material A for assembling the display device. When the display device assembly tape base material A has the light reflecting layer 3, for example, when used to integrate the display panel and the backlight housing, the light from the backlight housing is reflected later. Light can be efficiently guided to the display panel by reflecting in the direction of the plate 10.

  The light reflection layer 3 only needs to reflect light, and preferably contains a white colorant. Such a white colorant is not particularly limited, and examples thereof include titanium dioxide, barium sulfate, zinc white, lead white and the like, and titanium dioxide is preferable.

  The light reflecting layer 3 may be formed by applying and drying an ink capable of forming the light reflecting layer 3 on the light shielding layer 2, and preferably applying and drying a white ink containing a white colorant. What is necessary is just to form. At this time, it is preferable to perform the step of applying and drying the ink a plurality of times. For applying the ink, general-purpose means such as gravure printing, flexographic printing, and offset printing may be used.

  The white ink containing a white colorant preferably contains a white colorant, a binder, and a solvent. Since the binder and the solvent are the same as the black colorant, description thereof is omitted.

  As the content of the white colorant in the white ink, if the amount is small, the reflectance of the light reflecting layer decreases, and the thickness of the light reflecting layer cannot be reduced while maintaining sufficient light reflectance. When the surface roughness of the light reflection layer is increased and the pressure-sensitive adhesive layer is formed on the light reflection layer, the adhesion between the light reflection layer and the pressure-sensitive adhesive layer decreases, and the light reflection layer and the pressure-sensitive adhesive layer Since there exists a possibility that delamination may arise in between, 10 to 40 weight% is preferable and 15 to 30 weight% is more preferable.

  As the white ink, for example, white ink marketed by Dainippon Ink and Chemicals, Inc. under the trade name “Panacia CVL-SP709 White”, and commercially available from Teikoku Ink, Inc. under the trade name “EGS611 White”. White ink can be used.

  Further, if the content of the white colorant in the light reflecting layer 3 is small, the reflectance of the light reflecting layer is lowered, and the thickness of the light reflecting layer cannot be reduced while maintaining sufficient light reflectance. If the amount is large, the surface roughness of the light reflection layer increases, and when the pressure-sensitive adhesive layer is formed on the light reflection layer, the adhesion between the light reflection layer and the pressure-sensitive adhesive layer decreases, and the light reflection layer and Since there exists a possibility that delamination may arise between adhesive layers, 20 to 85 weight% is preferable.

In the light reflection layer 3, it is preferable that L ^* representing lightness in the L ^* a ^* b ^* color system specified by JIS Z8729 is larger than 85.

  If the thickness of the light reflecting layer 3 is thin, the light shielding layer is seen through the light reflecting layer, the color of the light reflecting layer is apparently gray, and light transmitted through the light reflecting layer is absorbed by the light shielding layer. As a result, there is a possibility that the light reflection performance of the light reflection layer 3 may be lowered. If the thickness is large, the thickness of the entire tape substrate for assembling the display device is increased, so 2 to 15 μm is preferable. In addition, the thickness of the light reflection layer 3 is obtained by cutting the tape base material for assembling the display device at an arbitrary position in the thickness direction, and observing the cut surface with an electron microscope. It is set as the arithmetic average value of thickness.

  As described above, the light shielding layer 2 is laminated and integrated on both surfaces of the base film 1, and the light reflecting layer 3 is provided on one of the light shielding layers 2, whereby the tape base material A for assembling the display device. As shown in FIGS. 2 and 3, the adhesive sheet B for assembling the display device is formed by laminating and integrating the adhesive layer 4 on at least one surface of the tape base material A for assembling the display device. Alternatively, as shown in FIG. 4, the display device assembly pressure-sensitive adhesive sheet B may be formed by laminating and integrating the pressure-sensitive adhesive layers 4 and 4 on both surfaces of the display device assembly tape base material A.

  It does not specifically limit as an adhesive which comprises this adhesive layer 4, An acrylic adhesive, a rubber adhesive, a silicone adhesive, etc. are mentioned. When the pressure-sensitive adhesive layers 4 and 4 are laminated and integrated on both surfaces of the display device assembly tape base material A, both the pressure-sensitive adhesive layers 4 and 4 may be the same or different.

  The acrylic pressure-sensitive adhesive includes a homopolymer of (meth) acrylic acid alkyl ester having 1 to 18 carbon atoms in the alkyl group, (meth) acrylic acid alkyl ester having 1 to 18 carbon atoms in the alkyl group and other functionalities. It preferably contains 50% by weight or more of a copolymer with a copolymerizable monomer such as a polymerizable monomer. In the present invention, (meth) acryl means acryl or methacryl.

  And since the adhesiveness of an acrylic adhesive may fall when there is little content of the C1-C18 (meth) acrylic-acid alkylester component in an acrylic adhesive in the number of carbon atoms, it is 50. % By weight or more is preferable, and 60% by weight or more is more preferable.

  The (meth) acrylic acid alkyl ester is not particularly limited. For example, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, (meth) acrylic Acid hexyl, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, normal decyl (meth) acrylate, isodecyl (meth) acrylate, lauryl (meth) acrylate, ( Examples include stearyl methacrylate.

  Examples of the functional monomer include a monomer having a hydroxyl group, a monomer having a carboxyl group, a monomer having an amide group, and a monomer having an amino group. Examples of the monomer having a hydroxyl group include hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate and hydroxypropyl (meth) acrylate.

  Examples of the monomer having a carboxyl group include α, β-unsaturated carboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid; monoalkyl maleates such as butyl maleate; and unreactive compounds such as maleic acid, fumaric acid, and itaconic acid. Examples thereof include dibasic acid anhydrides such as saturated dibasic acid and maleic anhydride.

  Furthermore, as a monomer having an amide group, (meth) acrylamide, dimethyl (meth) acrylamide, alkyl (meth) acrylamide such as diethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, N-ethoxymethyl (meth) N-alkoxymethyl (meth) acrylamide such as acrylamide, diacetone (meth) acrylamide and the like can be mentioned.

  Examples of the monomer having an amino group include dimethylaminoethyl (meth) acrylate. Examples of copolymerizable monomers other than the above include vinyl acetate, styrene, α-methylstyrene, vinyl chloride, acrylonitrile, ethylene, propylene, and the like.

  In addition, a tackifier, a crosslinking agent, etc. may be mix | blended with an acrylic adhesive as needed. Examples of such tackifiers include rosin resins, polyterpene resins, coumarone-indene resins, petroleum resins, and terpene-phenol resins. Examples of the crosslinking agent include an isocyanate crosslinking agent, an epoxy crosslinking agent, an oxazoline crosslinking agent, an aziridine crosslinking agent, and a metal chelate crosslinking agent.

  Furthermore, as the acrylic pressure-sensitive adhesive, a (meth) acrylic acid ester resin having a weight average molecular weight of 500,000 to 1,000,000 measured as a polystyrene-equivalent molecular weight by the GPC method, and a rosin ester resin having a hydroxyl value of 35 or more. And a terpene phenol resin having a hydroxyl value of 35 or more, and a pressure-sensitive adhesive having a gel fraction of 10 to 40% by weight is preferable. By using such a pressure-sensitive adhesive, the pressure-sensitive adhesive sheet for assembling the display device is preferable because sufficient pressure-sensitive adhesive force is exhibited even if the thickness of the pressure-sensitive adhesive layer is reduced to about 10 μm.

  Examples of the rubber adhesive include natural rubber, styrene-isoprene block copolymer, styrene-butadiene block copolymer, polyisoprene, polybutene, polyisobutylene, and ethylene-vinyl acetate copolymer. What contains 50 weight% or more of a body is mentioned.

  To the rubber elastic body, for example, an appropriate amount of a tackifier such as rosin resin, polyterpene resin, coumarone-indene resin, petroleum resin, terpene-phenol resin, and the like are added, and if necessary, liquid polybutene, Softeners such as mineral oil, liquid polyisoprene, and liquid polyacrylate are blended. Examples of the silicone-based pressure-sensitive adhesive include those containing 50% by weight or more of polydimethylsiloxane and the like.

  In addition, appropriate amounts of various additives such as anti-aging agents such as butylhydroxytoluene may be added to the pressure-sensitive adhesive. The pressure-sensitive adhesive layer 4 is preferably transparent, but the pressure-sensitive adhesive layer 4 laminated and integrated on the light reflecting layer 3 is white, and the pressure-sensitive adhesive layer 4 stacked and integrated on the light shielding layer 2 is black. May be colored.

  And as a point of laminating and integrating the pressure-sensitive adhesive layer 4 on one surface or both surfaces of the tape substrate A for display device assembly, there is no particular limitation, and the solution containing the pressure-sensitive adhesive on the tape substrate A for display device assembly. Alternatively, the dispersion can be applied directly using a comma coater, top feed reverse coater, etc., and the solution or dispersion containing the adhesive can be applied directly to the release treatment surface of the release film as described above. After drying, the release film is overlaid on the display device assembly tape substrate A so that the adhesive layer faces the display device assembly tape substrate A, and the adhesive layer is assembled to the display device assembly. For example, a method of transferring and laminating and integrating the tape base material A for use.

  If the thickness of the pressure-sensitive adhesive layer 4 is thin, the adhesiveness of the pressure-sensitive adhesive layer may be lowered. If the thickness is thick, the thickness of the pressure-sensitive adhesive sheet for assembling the display device is increased.

  Next, one mode of usage of the display device assembly pressure-sensitive adhesive sheet B will be described by taking the display device assembly pressure-sensitive adhesive sheet B shown in FIG. 4 as an example. The display device assembly adhesive sheet B is formed in a rectangular frame shape, and a display panel 6 such as a liquid crystal display panel or an organic EL (electroluminescence) panel is disposed and integrated in a backlight housing 5 to form a display module unit C. Used to configure.

  As shown in FIGS. 5 and 6, the backlight housing 5 is formed in a rectangular frame shape made of synthetic resin, and a flat rectangular frame-like panel arrangement for mounting the display panel 6 on the upper end portion. The installation step 51 is formed in an open state on the upper end surface of the backlight housing 5, and a reflection plate disposing step 52 for disposing the reflection plate 10 is provided on the lower end surface at the lower end. It is formed in a planar rectangular frame shape in an open state.

  A flat rectangular display panel 6 having a size slightly smaller than the upper end opening of the backlight housing 5 is disposed on the panel placement step 51 of the backlight housing 5. In the backlight housing 5, a plurality of optical films are disposed in a stacked state.

  Specifically, the light guide plate 7, the diffusion sheet 8, and one or a plurality of prism sheets 9, 9... For improving luminance are laminated in this order, and then the prism sheet 9 is formed. The prism sheet 9 is disposed in the backlight housing 5 so as to face the display panel 6 and to be substantially flush with the panel receiving surface 51a of the panel disposition step 51. In addition, optical films other than the above may be appropriately laminated.

  In addition, the reflector 10 is disposed and integrated with the reflector arrangement step 52 of the backlight casing 5, and an LED (not shown) is disposed in the backlight casing 5 as a light source. Has been.

  The display panel 6 and the prism sheet 9 facing the display panel 6 are integrated via a display device assembly pressure-sensitive adhesive sheet B. The display device assembly pressure-sensitive adhesive sheet B has a light-shielding layer 2 applied to the display panel 6 and light. The reflective layer 3 is disposed so as to face the prism sheet 9.

  The display device assembly pressure-sensitive adhesive sheet B is disposed on the panel receiving surface 51 a of the panel disposition step 51 of the backlight housing 5, and the panel disposition step of the backlight housing 5. Width dimension to reach from the inner peripheral edge of the panel receiving surface 51a of the portion 51 to the outer peripheral portion of the prism sheet 9 disposed in the opening surrounded by the panel receiving surface 51a of the panel mounting step 51 The panel receiving surface 51a and the prism sheet 9 of the step for disposing the panel of the backlight housing 5 and the display panel 6 are attached to the display device assembly adhesive on the entire periphery. The sheet B is bonded and integrated.

  In the above description, the optical film facing the display panel 6 is described as being the prism sheet 9, but the optical film facing the display panel 6 is not necessarily a prism sheet and may be another optical film.

  The display module unit C configured as described above is suitable for the thinning of small electronic devices such as mobile phones and electronic dictionaries since the display device assembly tape base material A is thinned. The display device assembly tape base material reflects the light from the light source with excellent light-shielding properties for preventing deterioration of the appearance of the display surface due to light entering the outer periphery of the display panel. The display module unit that exhibits excellent light reflectivity for efficiently guiding light to the display panel is thin and has excellent display performance.

  And since the light shielding layer 2 in the display device assembly tape substrate A of the display device assembly pressure-sensitive adhesive sheet B is thin and has a very low conductivity, the display panel 6 is not adversely affected. The display performance of 6 is not impaired.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the examples.

Example 1
A colorless and transparent polyethylene terephthalate film (trade name “5AF53” manufactured by Toray Industries, Inc.) having a thickness of 4.5 μm was prepared as the transparent substrate film 1. The polyethylene terephthalate film did not contain any colored pigment. Moreover, the corona discharge process was performed to both surfaces of the transparent base film 1, and the surface tension of both surfaces of the transparent ground film 1 was 50 mN / m.

  30 parts by weight of a urethane resin (halogen element content: less than 50 ppm) as a binder, 10 parts by weight of carbon black produced by a furnace method having an average particle size of 0.03 μm as a black colorant, and ethyl acetate, toluene and isopropyl alcohol A black ink made of black ink (carbon black: 10% by weight) consisting of 60 parts by weight of a solvent was prepared.

  A black ink was applied to one surface of the polyethylene terephthalate film 1 using a gravure printing method and dried to form a light-shielding base layer having a thickness of 1 μm. By coating and drying the black ink on the light shielding base layer using a gravure printing method, another light shielding base layer having a thickness of 1 μm was laminated and integrated on the light shielding base layer. The procedure of applying and drying black ink on the light shielding base layer was repeated a total of three times to form four light shielding base layers and a light shielding layer 2 having a thickness of 4 μm, which were laminated and integrated with each other. The content of carbon black in each light shielding base layer was 25% by weight.

  Further, on the other surface of the polyethylene terephthalate film 1, in the same manner, four light shielding base layers and a light shielding layer 2 having a thickness of 4 μm, which were laminated and integrated with each other were formed. The content of carbon black in each light shielding base layer was 25% by weight.

  Next, on the light shielding layer 2 laminated and integrated on one surface of the polyethylene terephthalate film 1, 25 parts by weight of a urethane resin (halogen element content: less than 50 ppm) as a binder, 25 parts by weight of titanium dioxide as a white colorant, and A white ink (titanium dioxide: 25% by weight) composed of 50 parts by weight of a solvent obtained by mixing ethyl acetate, toluene and isopropyl alcohol is applied and dried using a gravure printing method, and a light reflecting base layer having a thickness of 1.3 μm. Formed.

  Furthermore, the above-mentioned white ink was applied onto the light reflection base layer by using a gravure printing method, and dried, whereby another light reflection base layer having a thickness of 1.3 μm was laminated and integrated on the light reflection base layer. The procedure of applying and drying white ink on the light reflecting base layer was repeated a total of two times to form a light reflecting layer 3 having a thickness of 3.9 μm to form a tape substrate A for assembling a display device. In addition, the content rate of the titanium dioxide in each light reflection base layer was 50 weight%.

  Next, an acrylic pressure-sensitive adhesive (trade name “SK1717” manufactured by Soken Chemical Co., Ltd.) is applied on the light shielding layer 2 and the light reflecting layer 3 laminated and integrated on the other surface of the polyethylene terephthalate film 1 and dried. A pressure-sensitive adhesive layer 4 or 4 having a thickness of 20 μm was formed on each of the light reflection layers 3 to produce a pressure-sensitive adhesive sheet B for assembling a display device shown in FIG.

(Example 2)
A display device assembly pressure-sensitive adhesive sheet B shown in FIG. 4 was produced in the same manner as in Example 1 except that the light-shielding layer 2 having a thickness of 1 μm consisting of a single light-shielding base layer was formed on both surfaces of the polyethylene terephthalate film 1. .

(Example 3)
Applying black ink on the light-shielding base layer laminated and integrated on one surface of the polyethylene terephthalate film 1 and drying the total of one time instead of a total of three times, the light-shielding base layer is two layers, and the thickness formed by laminating and integrating each other is 2 μm 4 was produced in the same manner as in Example 1 except that the light shielding layer was formed.

Example 4
Thickness obtained by laminating and integrating 5 layers of light-shielding base layers with a total of 4 times instead of a total of 3 times for applying black ink on the light-shielding base layers laminated and integrated on both surfaces of the polyethylene terephthalate film 1, respectively. 4 was produced in the same manner as in Example 1 except that a light-shielding layer having a thickness of 5 μm was formed.

(Example 5)
Thickness obtained by laminating and integrating two light-shielding base layers, with black ink applied to the light-shielding base layer laminated and integrated on both surfaces of the polyethylene terephthalate film 1 and drying, with a total of once instead of three times. 4 was produced in the same manner as in Example 1 except that a light-shielding layer having a thickness of 2 μm was formed.

(Comparative Example 1)
On one surface of the polyethylene terephthalate film 1, the light-shielding base layer is formed of 8 layers, and the light-shielding layer 2 having a thickness of 8 μm is formed. The polyethylene terephthalate film 1 is formed on the other surface without forming the light-shielding layer. A pressure-sensitive adhesive sheet for assembling a display device in the same manner as in Example 1 except that the light reflecting base layer 3 was formed directly on the other surface of the film 1 and the light reflecting layer 3 having a thickness of 3.9 μm was laminated and integrated. B was produced.

(Comparative Example 2)
A white resin film (trade name “Teflex” manufactured by Teijin Ltd., thickness: 13 μm, total light transmittance: 30 to 40%) was prepared as a base film, and the same black ink as in Example 1 was prepared.

  Next, black ink was applied to one surface of the white resin film by gravure printing and dried to form a light-shielding base layer having a thickness of 1 μm. By coating and drying the black ink on the light shielding base layer by gravure printing and drying, another light shielding base layer having a thickness of 1 μm was laminated and integrated on the light shielding base layer. The procedure of applying and drying black ink on the light shielding base layer is repeated a total of 7 times to form a light shielding layer having a thickness of 8 μm formed by stacking and integrating the light shielding base layers, and forming a tape substrate for assembling the display device. Formed.

  Next, on the other surface of the white resin film and the light shielding layer, an acrylic pressure-sensitive adhesive was applied and dried to form a pressure-sensitive adhesive layer having a thickness of 1.5 μm, thereby manufacturing a pressure-sensitive adhesive sheet for assembling a display device.

(Comparative Example 3)
The display device assembly pressure-sensitive adhesive sheet B shown in FIG. 4 was prepared in the same manner as in Example 1 except that the light-shielding layer 2 having a thickness of 0.5 μm consisting of one light-shielding base layer was formed on each of both surfaces of the polyethylene terephthalate film 1. Manufactured.

(Comparative Example 4)
Applying black ink on the light-shielding base layer formed on the other surface of the polyethylene terephthalate film and drying the black ink on the light-shielding base layer for a total of 5 times instead of a total of 6 times. A display device assembly pressure-sensitive adhesive sheet B shown in FIG. 4 was produced in the same manner as in Example 1 except that was formed.

(Comparative Example 5)
A white resin film (trade name “Teflex” manufactured by Teijin Ltd., thickness: 13 μm, total light transmittance: 30 to 40%) was prepared as a base film, and the same black ink as in Example 1 was prepared.

  Next, black ink was applied to one surface of the white resin film by gravure printing and dried to form a light shielding layer composed of a light shielding base layer having a thickness of 1 μm. Thereafter, an acrylic pressure-sensitive adhesive (trade name “SK1717” manufactured by Soken Chemical Co., Ltd.) is applied on the other side of the white resin film and the light shielding layer and dried, and the thickness on each of the other side of the white resin film and the light shielding layer is increased. A 20 μm pressure-sensitive adhesive layer was formed to produce a pressure-sensitive adhesive sheet for assembling a display device.

(Comparative Example 6)
A white resin film (trade name “Teflex” manufactured by Teijin Ltd., thickness: 13 μm, total light transmittance: 30 to 40%) was prepared as a base film, and the same black ink as in Example 1 was prepared.

  Next, black ink was applied to one surface of the white resin film by gravure printing and dried to form a light-shielding base layer having a thickness of 1 μm. By coating and drying the black ink on the light shielding base layer by gravure printing and drying, another light shielding base layer having a thickness of 1 μm was laminated and integrated on the light shielding base layer. The procedure of applying and drying black ink on the light-shielding base layer is repeated a total of 5 times to form 6 layers of light-shielding base layers and a 6 μm-thickness light-shielding layer that are laminated and integrated with each other to form a tape substrate for assembling a display device. Formed.

  Next, an acrylic pressure-sensitive adhesive (trade name “SK1717”, manufactured by Soken Chemical Co., Ltd.) is applied on the other surface of the white resin film and the light shielding layer, and dried. A 20 μm pressure-sensitive adhesive layer was formed to produce a pressure-sensitive adhesive sheet for assembling a display device.

(Comparative Example 7)
The procedure of applying and drying black ink on the light shielding base layer was repeated 9 times in total instead of 5 times in total, except that 10 light shielding base layers and a light shielding layer having a thickness of 10 μm formed by laminating and integrating each other were formed. Produced a display device assembly pressure-sensitive adhesive sheet in the same manner as in Comparative Example 6.

(Comparative Example 8)
A transparent resin film (trade name “Taiko Polyester Film # 23FE2002”, manufactured by Futamura Co., Ltd., thickness: 23 μm, total light transmittance: 85 to 95%) was prepared as a base film.

  Next, an acrylic pressure-sensitive adhesive (trade name “SK1717” manufactured by Soken Chemical Co., Ltd.) is applied to both sides of the transparent resin film and dried to form a pressure-sensitive adhesive layer having a thickness of 20 μm on each side of the transparent resin film. A pressure-sensitive adhesive sheet for assembling the apparatus was produced.

(Comparative Example 9)
Except that the light-shielding layer 2 having a thickness of 1 μm consisting of a single light-shielding base layer was formed on both sides of the polyethylene terephthalate film 1, and that Ketjen Black (Ketjen Black EC manufactured by Mitsubishi Chemical Corporation) was used as carbon black. The display device assembly pressure-sensitive adhesive sheet B shown in FIG. 4 was produced in the same manner as in Example 1.

(Comparative Example 10)
On one surface of the polyethylene terephthalate film 1, 6 layers of light shielding base layers and a light-shielding layer 2 having a thickness of 6 .mu.m formed by laminating each other were formed. Without forming a light-shielding layer on the other surface of the polyethylene terephthalate film 1, A pressure-sensitive adhesive sheet for assembling a display device in the same manner as in Example 1 except that the light reflecting base layer 3 was formed directly on the other surface of the film 1 and the light reflecting layer 3 having a thickness of 3.9 μm was laminated and integrated. B was produced.

(Comparative Example 11)
On one surface of the polyethylene terephthalate film 1, the light-shielding base layer is formed of 10 layers, and the light-shielding layer 2 having a thickness of 10 μm is formed. The polyethylene terephthalate film 1 is formed on the other surface without forming the light-shielding layer. A pressure-sensitive adhesive sheet for assembling a display device in the same manner as in Example 1 except that the light reflecting base layer 3 was formed directly on the other surface of the film 1 and the light reflecting layer 3 having a thickness of 3.9 μm was laminated and integrated. B was produced.

  The light reflectance, lightness, light shielding property, conductivity of the light shielding layer and the number of pinholes of the obtained pressure-sensitive adhesive sheet for assembling the display device were measured in the following manner, and the results are shown in Table 1. Using the obtained adhesive sheet for assembling the display device, whether or not the electronic device operates normally was confirmed in the following manner, and the result is shown in Table 1.

(Light reflectance)
The total light reflectance at 500 nm was measured for the light reflecting layer of the adhesive sheet for assembling the display device in accordance with JIS K7105. For Comparative Example 2, the light reflectance of the white resin film was measured.

(brightness)
The light reflecting layer and the light-shielding layer of the pressure-sensitive adhesive sheet for a display device assembly, the L ^* representing the L ^* a ^* b ^* lightness of color system was measured in accordance with JIS Z8729. In Comparative Example 2, the brightness of the white resin film was measured as the brightness of the light reflecting layer.

(Light shielding)
The total light transmittance based on JIS K7105 was measured about the light shielding layer of the adhesive sheet for a display apparatus assembly.

(Conductivity of light shielding layer)
Three flat square test pieces T each having a side of 50 mm were cut out from the display device assembly tape base material. Next, as shown in FIG. 7, two iron needles N ₁ and N ₂ were pierced into each test piece T so as to be parallel to each other with an interval W ₁ of 10 mm. The two needles N ₁ and N ₂ were allowed to penetrate from the other surface side of the test piece T to the one surface side and then penetrated from the one surface side to the other surface side. The distance W ₂ between the two points through which the needles N ₁ and N ₂ penetrate the test piece T was 10 mm. One side or the other side of the test piece corresponds to one side or the other side of the base film when the display device assembly tape base material is manufactured.

Next, is brought into contact with the measuring needle S ₁ to one needle N _1, is brought into contact with the measuring needle S ₂ to the other needle N _2, the resistance value was measured for each test piece T, the The arithmetic average value of the resistance values of the test piece T was defined as the conductivity of the light shielding layer.

(Number of pinholes)
A tape base material for assembling the display device was placed on the upper end opening of the cylindrical body so as to completely close the upper end opening. A light source (trade name “Dycrobeam 110V 65W beam angle 10 ° model number JDR110V65WKN / 5E11” manufactured by National Corporation) was disposed in the cylindrical body, and light was irradiated from the light source to the tape substrate for assembling the display device. Then, the number of pinholes was measured by visually observing the display device assembling tape base material from a position 30 cm vertically upward. The vertical distance from the light source to the lower surface of the display device assembly tape substrate was 20 cm. In the tape base materials for display device assembly of Comparative Examples 3 and 5, since light was transmitted through the entire surface, the presence or absence of pinholes could not be confirmed.

  The tape substrate for assembling the display device of Comparative Example 3 was not measured for the presence or absence of pinholes because it was totally transmitting light.

(Operation of electronic equipment)
When mounting a CPU (central processing unit) of a commercially available personal computer on the motherboard, the CPU's conductive terminals were passed through the display device assembly tape substrate and then mounted on the motherboard. Then, the personal computer was started and it was confirmed whether it started normally. If the tape substrate for assembling the display device is conductive, the personal computer will not start up normally. The case where it started normally was set as "good", and the case where it started normally was set as "bad".

  The present invention has excellent light-shielding properties and light-reflecting properties, and the display panel control device can be reliably maintained without causing malfunction of the display panel control device due to the current flowing in the light-shielding layer. It can be used for a display module unit using a display panel such as a liquid crystal display panel or an organic EL (Electroluminescence) panel.

DESCRIPTION OF SYMBOLS 1 Base film 2 Light shielding layer 3 Light reflection layer 4 Adhesive layer 5 Backlight housing | casing 6 Display panel A Display apparatus assembly tape base material B Display apparatus assembly adhesive sheet C Display module unit

Claims (4)

A base film, a light-shielding layer having a thickness of 1 to 5 μm containing carbon black laminated and integrated on both surfaces of the base film and manufactured by a furnace method as a black colorant, and any one of the light-shielding layers A tape base material for assembling a display device, comprising: a light reflection layer laminated and integrated on the light shielding layer. 2. The display device assembling tape substrate according to claim 1, wherein both surfaces of the substrate film are subjected to corona discharge treatment. A pressure-sensitive adhesive sheet for assembling a display device, wherein a pressure-sensitive adhesive layer is laminated and integrated on at least one surface of the tape substrate for assembling the display device according to claim 1. A frame-shaped backlight housing having a panel disposition step formed on the inner peripheral surface, and a display device assembly pressure-sensitive adhesive sheet disposed on the panel disposition step, comprising a base film, Stacked and integrated on either one of the light-shielding layer and the light-shielding layer having a thickness of 1 to 5 μm and containing carbon black produced by the furnace method as a black colorant. A display device assembly pressure-sensitive adhesive sheet comprising a light-reflecting layer and a pressure-sensitive adhesive layer laminated and integrated on at least one surface of the display device assembly tape substrate; A display module unit comprising: a display panel disposed on an adhesive sheet for assembling the apparatus; and a plurality of optical films disposed in a laminated state in the backlight casing. Tsu door.

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