JP2010222523A - Light-shielding reflective tape and lcd (liquid crystal display) module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light-shielding reflective tape capable of forming a light absorbing area and a light diffusing area suppressive of uneven light at an image display terminal at low cost and an arbitrary process. <P>SOLUTION: The light-shielding reflective tape, used by being applied between an LCD panel of the LCD module and a backlight case, has a support medium having at least a light-shielding layer and a light reflective layer, and an adhesive layer placed at the light reflective layer side of the support medium, wherein the light reflective layer or the adhesive layer includes a color developer which develops a color by light or heat, or by means of the light-shielding reflective tape having a color developing layer including the color developer which develops the color by the light or heat between the light reflective layer and the adhesive agent layer, the layer of the light-reflecting layer-side can be changed in the color to a dark color due to light or heat in a processing step after production of the light-shielding reflective tape. Thus, the light absorbing area and the light diffusing area capable of suppression of uneven light at the image display terminal can be formed at low cost and with an arbitrary step. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a pressure-sensitive adhesive tape having both light reflectivity and light shielding properties, which is used by being attached between an LCD (Liquid Crystal Display) panel and a backlight housing.

LCD modules (liquid crystal display devices) are used in a wide range of fields such as word processors and personal computers. Especially, electronic notebooks, mobile phones, PHS, etc. are used as display devices for increasingly smaller electronic devices. It has become. Among such LCD modules, for example, a sidelight type backlight type LCD module generally includes a reflector, a light guide plate, a diffusion sheet, and a prism sheet (if necessary) in a backlight casing ( The LCD panel is laminated in order, and a light source such as an LED (Light Emitting Diode) or a cold cathode tube provided with a lamp reflector on the side of the light guide plate is disposed.
Furthermore, an adhesive tape (usually punched into a frame shape, and the width is usually about 0.5 mm to about 10 mm) is sandwiched between the LCD panel and the backlight housing. Adhesive tape not only touches the backlight housing but also contacts the prism sheet, fixing the diffusion sheet installed under the prism sheet, and preventing impact of dust and cushioning. It also has a role to prevent cracking of the above parts.

  In an electronic device incorporating the LCD module as described above, the terminal itself is required to be thin, thin, and small, while the demand for an increase in information amount and high definition requires a large screen of the image display unit. ing. For this reason, since recent LCD modules have a configuration in which the positions of the light source and the LCD panel are closer to those of the conventional LCD module, the adhesive tape is required to be further reduced in thickness.

  In addition, the adhesive tape sandwiched between the LCD panel and the backlight housing is required to have a high light shielding property, improving the appearance of the display surface of the LCD panel and at the same time transmitting light to the driver for driving the LCD panel. It is also required to have the role of blocking entry and preventing malfunction. Furthermore, high light reflection performance is also required for reflecting light entering the peripheral portion of the backlight housing and efficiently guiding light from the light source to the back surface of the LCD panel. As a result, it is possible to deal with a thin portable device and achieve power saving.

  However, due to recent improvements in backlight performance and the addition of light reflectivity with adhesive tape, the brightness of the image display area is increased. On the other hand, when the light source is close to the LCD panel, the outer frame of the image display area Depending on the mode of use, such as when the image is narrow, there is a problem in that the end of the image display unit becomes too bright and luminance unevenness occurs in the image display unit.

  In order to solve such a problem, a light-shielding reflective tape in which a light-absorbing layer or a light-diffusing layer is provided on a part of the light-reflective layer by printing or the like is disclosed as a light-shielding reflective tape that can suppress uneven brightness (Patent Document 1) reference). The light-shielding reflective tape is disclosed that the light reflectivity can be suitably controlled by a light absorbing layer or the like provided in the light reflecting layer. However, it is necessary to print the light-shielding / reflecting tape having the above configuration in the process before providing the pressure-sensitive adhesive layer, and it is necessary to provide printing in consideration of the final product configuration before punching or the like is performed. is there. Therefore, once printed patterns cannot be changed later, it is necessary to appropriately manufacture the original fabric provided with a printing layer according to the product configuration for each type of product, resulting in a very high manufacturing cost. was there. In addition, since a precise punching process is required according to the printed pattern, in a light-shielding reflective tape used for a small electronic terminal, it is difficult to punch a pattern formed in a narrow width, Yield improvement was difficult due to the occurrence of machining errors and the need for punching at low speed.

JP 2007-169322 A

  The subject of this invention is providing the light-shielding reflective tape which can form the light absorption area | region and light-diffusion area | region which can suppress the light spot nonuniformity of an image display part edge part at low cost and arbitrary processes.

  The present inventors examined a tape in which the layer on the light reflection layer side is changed to a dark color by light or heat in the processing step after the production of the light-shielding reflection tape. As a result, it has been found that the above-mentioned problems can be solved by a light-shielding reflective tape containing a pressure-sensitive adhesive, a light reflecting layer, or a color former that develops color by light or heat between the light reflecting layer and the pressure-sensitive adhesive.

That is, the present invention is a light-shielding reflective tape used by being stuck between the LCD panel of the LCD module and the backlight housing,
A support having at least a light shielding layer and a light reflection layer, and a pressure-sensitive adhesive layer provided on the light reflection layer side of the support,
The light reflecting layer or pressure-sensitive adhesive layer contains a color former that develops color by light or heat, or a color that contains a color former that develops color by light or heat between the light reflective layer and the pressure-sensitive adhesive layer. A light-shielding reflective tape having a layer is provided.

  The light-shielding reflective tape of the present invention is a light-absorbing region and a light-diffusing region that can suppress light spot unevenness at the edge of the image display unit, any manufacturing process during the process of manufacturing the light-shielding reflective tape, or after punching of the light-shielding reflective tape. Any process can be formed as appropriate. Such a light-shielding reflective tape of the present invention does not require the production of an original fabric having a printing conforming to the product configuration for each product, and does not require a punching process in accordance with the printing, so it can be easily punched at a high speed. As a result, it is possible to greatly reduce manufacturing costs and improve the degree of freedom in product design.

  Below, the light-shielding reflective tape which has both the light reflectivity and light-shielding property of this invention is demonstrated in more detail based on the component.

  The light-shielding reflective tape of the present invention has a support having a light-shielding layer and a light reflecting layer, and an adhesive layer provided on the light reflecting layer side of the support, and the light reflecting layer or the adhesive layer is light or It contains a color former that develops color by heat, or has a color development layer that contains a color former that develops color by light or heat between the light reflecting layer and the pressure-sensitive adhesive layer. For this reason, in the processing step after the manufacture of the light-shielding reflective tape, it is possible to control the reflectivity on the reflective surface side of the light-shielding reflective tape by applying light or heat to necessary portions of the light-shielding reflective tape. As a result, when used for fixing the LCD module, improvement in the average luminance of the LCD module and suppression of light spot unevenness at the edge of the LCD module can be achieved at a low cost and at a high level.

[Coloring agent that develops color by light or heat]
As the color former contained in the light reflection layer, the pressure-sensitive adhesive layer, or the color development layer provided between the light reflection layer and the pressure-sensitive adhesive, one that changes to a dark color by light or heat is used. Among them, the color former is preferably a laser color former that develops color with laser light.

(Coloring agent that develops color with laser)
As the color former having laser colorability used in the present invention, a known color former that changes color to dark color, preferably black, by laser light can be used. The color former includes a color former mainly composed of inorganic particles using a metal compound, a color development component such as a leuco dye, and a color developer such as a phenol methylol compound. Examples of the color former include a color former mainly composed of inorganic particles using a metal compound as a color former having high sensitivity to laser light and having stable color development over time. Among them, color former particles using metal complex oxides such as copper and molybdenum, and inorganic particles containing metal compounds that can form chelates have amino groups with good black color development due to thermal stimulation during laser irradiation. Color former particles coordinated with a hydrocarbon compound can be suitably used.

  As the metal capable of forming a chelate, metal species such as copper, molybdenum, manganese, iron, magnesium, and nickel are preferable, and metal compounds such as metal oxides, hydroxides, and alkoxides that are highly coordinated to amino groups. Particularly preferred. The metal compound may be a simple substance or two kinds of metal compounds. As the inorganic particles used for the inorganic particles containing a metal compound, silica, titanium oxide, calcium carbonate, alumina and the like are preferable, and since they are used as an adhesive for overlaminate, silica, titanium oxide, and alumina that are not colored as much as possible are used. Particles are particularly preferred. As the hydrocarbon compound having an amino group, a primary amine or a secondary amine is used.

  An anti-aging agent is preferably added to the layer having a color former. As the anti-aging agent, a hindered amine type is particularly preferable.

[Support]
The support used for the light-shielding reflective tape of the present invention has at least a light-shielding layer and a light reflecting layer. The configuration of each layer is not particularly limited as long as one surface of the support has light shielding properties and the other surface has light reflectivity.

(Base material layer)
In the light-shielding / reflecting tape of the present invention, the light-shielding layer or the light-reflecting film is formed by using a light-shielding or light-reflecting resin film, even if the light-shielding layer or the light-reflecting layer is combined with the base material layer. A layer other than the layer may be provided as the base material layer. When the light shielding layer, the light reflecting layer, and the base material layer are used as a common layer, it is easy to contribute to the reduction in thickness of the light shielding reflective tape. On the other hand, the light shielding layer, the light reflecting layer, and the base material layer are separated from each other. In the case of constituting as a layer, it is preferable because it is easy to improve and control the light shielding property and the light reflecting property.

  As the said base material layer, the well-known and usual resin film etc. which are used for an adhesive sheet can be used, For example, cellophane, polyethylene, a polypropylene, nylon, a polystyrene, a polyimide, polyester etc. are mentioned. Among these, polyester is preferably used because it is excellent in strength and insulation. The resin film may be colored in a color such as white, silver, black, or gray in order to impart light reflectivity or light shielding. Various known additives such as an antioxidant and an antistatic agent may be added to the resin film.

  When the base material layer is made of a transparent resin film, even if the light shielding layer and the light reflecting layer are laminated on one surface of the base material layer, the light shielding layer is laminated on one surface of the base material layer, Since a light reflecting layer may be laminated on the surface, a transparent resin film is preferable because the design of the structure becomes easy. On the other hand, when the base material layer is colored, it is preferable because it is easy to improve the light shielding property and control the light reflectivity.

  As thickness of a base material layer, 3-100 micrometers is preferable. When the thickness is 3 μm or more, the film is hardly cracked at the time of peeling, and when it is 100 μm or less, peeling is hardly generated at the time of applying the phase. More preferably, it is 12-50 micrometers.

(Light shielding layer)
As long as the light shielding layer has a function of shielding the light from the light source of the LCD module, it may be a dark color other than black or silver, for example, purple or amber, or any structure. good. Hereinafter, preferable examples of the light shielding layer in the pressure-sensitive adhesive tape of the present invention will be described.

  When a black ink layer is used as the light shielding layer, black ink using carbon black or the like as a pigment can be used. The thickness of the black ink layer is preferably 0.5 to 5 μm. The black ink layer may be a single layer, but is preferably laminated in 2 to 4 layers from the viewpoint of preventing pinholes.

  Examples of the composition of the black ink include polyester resins, vinyl chloride / vinyl acetate resins, acrylic resins, nitrocellulose resins, polyurethane resins, and polyester urethane resins. Among them, a polyester urethane resin having a tan δ peak temperature of −30 to 30 ° C. measured by a dynamic viscoelastic spectrum at a frequency of 1 Hz is preferable.

The peak temperature of tan δ of the polyester urethane resin is measured by the following method. Polyester urethane resin is formed to a thickness of 50 μm with a bar coater. Next, from a specimen cut to a sample length of 20 mm (sample length of 20 mm, film thickness of 50 μm) using a viscoelasticity tester from −150 ° C. to 250 ° C. at a frequency of 1 Hz and a temperature increase time of 3 ° C./1 minute. The storage elastic modulus (G ′) and the loss elastic modulus (G ″) are measured. The loss tangent tan δ is calculated by the following calculation formula.
Loss tangent tan δ = G ″ / G ′
Examples of the viscoelasticity tester include DMS210, DMS220, and DMS6100 manufactured by Seiko Instruments Inc.

As the ink printing method, printing can be performed by a known and common method. For example, letterpress printing, flexographic printing, dry offset printing, gravure printing, gravure offset printing, offset printing, screen printing, and the like can be employed. Among them, the gravure printing is suitable for the repeated coating.
The film surface to be ink-coated is preferably subjected to a known and commonly used easy adhesion treatment. Of these, easy adhesion treatment selected from corona treatment, plasma treatment, and primer treatment is preferred.

(Light reflecting layer)
Although a light reflection layer is not specifically limited, It is preferable that a reflectance is 60% or more, More preferably, it is 80% or more, Most preferably, it is 90% or more. The higher the reflectivity, the higher the brightness improvement effect. Examples of such reflective materials include resin films deposited with metals such as silver and aluminum, white resin films, white ink layers made of ink containing white or silver colorants on resin films, and silver ink layers. Examples include laminated films and laminates of thin films such as 3M ESR. Especially, since control of light reflectivity is easy, the light reflection layer which consists of a white ink layer can be used conveniently. Examples of commercially available light reflecting films include Reiko 37W01, 3M ESR, Toray E # 38, Mitsubishi Chemical Polyester Film W400 # 38, Teijin DuPont Teflex FW2 # 13, etc. It is preferable because of its high reflectivity.

  In the case where the light reflecting layer has the same structure as the base material layer and there is no base material layer between the light reflecting layer and the light shielding layer, the reflective property is not provided between the light reflecting layer and the light shielding layer. In order to increase, it is preferable to provide a white resin coat, a silver resin coat, or a metal vapor deposition layer.

  When a white ink layer is used as the light reflection layer, the composition of the white ink is, for example, polyester resin, vinyl chloride / vinyl acetate resin, acrylic resin, nitrocellulose resin, polyurethane resin, polyester. A urethane resin is mentioned. Among them, a polyester urethane resin having a tan δ peak temperature of −30 to 30 ° C. measured by a dynamic viscoelastic spectrum at a frequency of 1 Hz is preferable.

  Lamination of the white ink layer on the resin film is preferable because a printing method by a known and commonly used printing method is easy. For example, letterpress printing, flexographic printing, dry offset printing, gravure printing, gravure offset printing, offset printing, screen printing, and the like can be employed. Among them, the gravure printing is suitable for the repeated coating.

  The surface of the resin film to be ink-coated is preferably subjected to a known and commonly used easy adhesion treatment. Of these, easy adhesion treatment selected from corona treatment, plasma treatment, and primer treatment is preferred.

  When the light reflecting layer contains the color former, the light reflecting layer is preferably formed of white ink. The content of the color former may be appropriately adjusted according to the type of color former used and the degree of color development. However, the content is preferably 10 to 60 parts by mass with respect to 100 parts by mass of the solid content of the white ink. More preferably, it is 20-50 mass parts. Within the above range, color development and yellowing resistance are both highly compatible.

(Coloring layer)
In the present invention, a coloring layer containing a coloring agent that develops color by light or heat may be provided between the light reflecting layer and the pressure-sensitive adhesive layer. In order to simplify the manufacturing process, it is preferable to include a color former in the light reflecting layer or the pressure-sensitive adhesive layer. However, in terms of color clarity and durability, a separate color is formed between the reflective layer and the pressure-sensitive adhesive layer. It is preferable to provide a layer.

  The color developing layer is not particularly limited as long as it can ensure the light reflecting performance of the light reflecting layer, the transparency of the pressure-sensitive adhesive layer, the adhesion with the light reflecting layer or the pressure-sensitive adhesive layer, etc., but is easy to manufacture. In order to easily control the function of the light-shielding / reflecting tape, a layer made of a transparent ink containing the color former is preferable.

  When a transparent ink is used as the color forming layer, examples thereof include polyester resins, vinyl chloride / vinyl acetate resins, acrylic resins, nitrocellulose resins, polyurethane resins, and polyester urethane resins. Among them, a polyester urethane resin having a tan δ peak temperature of −30 to 30 ° C. measured by a dynamic viscoelastic spectrum at a frequency of 1 Hz is preferable.

[Adhesive layer]
As the pressure-sensitive adhesive layer used in the present invention, a resin film or a light-shielding layer that has good adhesiveness can be used, and known acrylic, rubber-based, or silicon-based pressure-sensitive adhesive resins can be used. Among them, an acrylic copolymer containing a repeating unit derived from an acrylate ester having an alkyl group having 2 to 14 carbon atoms as a repeating unit is preferable from the viewpoint of light resistance and heat resistance.

  Examples of the acrylic copolymer include acrylic copolymers containing repeating units derived from n-butyl acrylate, isooctyl acrylate, 2-ethylhexyl acrylate, isononyl acrylate, ethyl acrylate, and the like. Among these, those having a halogen content of 0.3% by mass or less are preferable, those having a halogen content of 0.1% by mass or less are more preferable, and those having substantially no halogen are particularly preferable. Among them, as a repeating unit, those containing 50% by mass or more of n-butyl acrylate units are excellent in adhesion to an ink layer using a polyester urethane resin, more preferably those containing 90% by mass or more are excellent in adhesion. .

  Furthermore, as a repeating unit, a repeating unit derived from an acrylate ester having a polar group such as a hydroxyl group, a carboxyl group or an amino group in the side chain or other vinyl monomer is contained in a range of 0.1 to 15% by mass. Is preferred. Moreover, it is excellent in adhesiveness with the ink layer which uses a polyester urethane type resin to contain an acrylic acid unit in 2-10 mass%.

  The acrylic copolymer can be obtained by copolymerization by a solution polymerization method, a bulk polymerization method, a suspension polymerization method, an emulsion polymerization method, an ultraviolet irradiation method, or an electron beam irradiation method. The average mass molecular weight of the acrylic copolymer is preferably 400,000 to 1,400,000, more preferably 600,000 to 1,200,000 in order to achieve both coating properties and adhesive properties. The average mass molecular weight is a standard polystyrene conversion by gel permeation chromatography (GPC). As measurement conditions, TSKgel GMHXL [manufactured by Tosoh] is used as the column, the column temperature is 40 ° C., the eluent is tetrahydrofuran, the flow rate is 1.0 mL / min, and the standard polystyrene is TSK standard polystyrene.

  Furthermore, it is preferable to add a crosslinking agent in order to increase the cohesive strength of the pressure-sensitive adhesive. Examples of the crosslinking agent include an isocyanate crosslinking agent, an epoxy crosslinking agent, and a chelate crosslinking agent. In particular, when an adhesive layer is provided, it is preferable to use an isocyanate crosslinking agent or an epoxy crosslinking agent. The addition amount of the crosslinking agent is preferably adjusted so that the gel fraction of the pressure-sensitive adhesive layer is 25 to 80%. A more preferable gel fraction is 30 to 70%. Among these, 35 to 60% is most preferable. When the gel fraction is 25% or more, the pressure-sensitive adhesive has an appropriate cohesive force, so that adhesive residue is hardly generated when reworking. On the other hand, when the gel fraction is 80% or less, the pressure-sensitive adhesive does not become too hard and the adhesive strength is good. Adhesiveness decreases. The gel fraction is expressed as a percentage of the original mass by immersing the composition of the pressure-sensitive adhesive layer after curing in toluene, measuring the mass after drying of the insoluble matter remaining after standing for 24 hours, and measuring the mass.

  Furthermore, in order to improve the adhesive strength of the pressure-sensitive adhesive layer, a tackifier resin may be added. The tackifier resin to be added to the pressure-sensitive adhesive layer of the pressure-sensitive adhesive tape of the present invention is a rosin resin such as rosin or an esterified product of rosin; a terpene resin such as a diterpene polymer or an α-pinene-phenol copolymer; Petroleum resins such as (C5) and aromatic (C9); styrene resins, phenol resins, xylene resins, and the like. An acrylic resin other than the acrylic copolymer may be added as a tackifying resin.

  As addition amount of tackifying resin, when an adhesive resin is an acrylic copolymer, it is preferable to add 10-60 mass parts with respect to 100 mass parts of acrylic copolymers. When attaching importance to adhesiveness, it is most preferable to add 20 to 50 parts by mass. When the adhesive resin is a rubber-based resin, it is preferable to add 80 to 150 parts by mass of the tackifier resin to 100 parts by mass of the rubber-based resin. In general, when the adhesive resin is a silicon resin, no tackifying resin is added.

  Moreover, black colorants, such as carbon black, and other well-known usual additives can be added as needed. Examples of other additives include plasticizers, softeners, fillers, pigments, flame retardants, and the like.

  The loss tangent of the dynamic viscoelastic spectrum at a frequency of 1 Hz of the pressure-sensitive adhesive layer is preferably 0.5 to 0.70 at 85 ° C. More preferably, it is 0.55-0.65. If it is less than 0.5, the pressure-sensitive adhesive becomes too hard, and the initial adhesion and resilience resistance are lowered. On the other hand, when it exceeds 0.70, the pressure-sensitive adhesive becomes too soft, and the pressure-sensitive adhesive stretches at high temperatures and peeling easily occurs.

  The dynamic viscoelasticity of the pressure-sensitive adhesive layer in the present invention is obtained by sandwiching a test piece between parallel disks, which are measuring parts of the tester, using a viscoelasticity tester (manufactured by Rheometrics, trade name: Ares 2KSTD). Then, the storage elastic modulus (G ′) and the loss elastic modulus (G ″) at a frequency of 1 Hz are measured, and the loss tangent is calculated by an expression represented by tan δ = (G ″) / (G ′). In the test piece, an adhesive having a thickness of 0.5 to 2.5 mm may be sandwiched between parallel disks alone, or a laminate of a base material and an adhesive may be stacked in layers and sandwiched between parallel disks. In the latter case, the thickness of the pressure-sensitive adhesive alone is adjusted to be in the above range. When the thickness of the pressure-sensitive adhesive is adjusted to the above range, the dynamic viscoelastic spectrum of the pressure-sensitive adhesive can be measured in the same manner as when there is no base material even if the base material is sandwiched between them.

  As for the thickness of an adhesive layer, 5-50 micrometers is preferable, More preferably, it is 10-30 micrometers. If it is 5 μm or more, sufficient adhesiveness can be obtained, and if it is 50 μm or less, it can be suitably applied to a display device and the like that are becoming lighter and thinner.

  The content of the color former in the case where the pressure-sensitive adhesive layer contains the color former may be appropriately adjusted depending on the type of color former used and the degree of color development, but with respect to 100 parts by mass of the solid content of the pressure-sensitive adhesive composition, The content is preferably 10 to 40 parts by mass.

[Shading reflection tape]
As described above, the light-reflective tape of the present invention contains a color former that develops color by light or heat in the light reflection layer or the pressure-sensitive adhesive layer, or light or heat between the light reflection layer and the pressure-sensitive adhesive layer. Because it has a coloring layer that contains a color former that develops color, the reflective properties of the reflective surface of the light-shielding reflective tape can be improved by applying light or heat to the necessary part of the light-shielding reflective tape in the processing step after manufacturing the light-shielding reflective tape. Can be controlled. As a result, when pasted between the LCD panel and the backlight housing, the average luminance of the LCD module can be improved and the unevenness of the edge of the LCD module can be suppressed at a low cost and at a high level.

  The thickness of the light-shielding reflective tape of the present invention is preferably 20 to 100 μm. More preferably, it is 30-75 micrometers, and it is especially preferable that it is 40-65 micrometers among these.

  When the light-shielding reflective tape of the present invention is applied between the LCD panel of the LCD module and the backlight housing, the light-reflecting layer side is usually the backlight housing and the light-shielding layer side is the LCD panel. paste. In such an aspect, the ratio of the adhesive force of the pressure-sensitive adhesive layer provided on the light reflecting layer side to the backlight housing and the adhesive force of the pressure-sensitive adhesive layer provided on the light shielding layer side to the LCD panel is preferable. The range is preferably 10: 1 to 10: 9, more preferably 10: 2 to 10: 8. Of these, 10: 3 to 10: 7 is most preferable.

  Moreover, it is preferable that the adhesive force with respect to the backlight housing | casing of the adhesive layer provided in the light reflection layer side is less than 10N / 10mm, and it is more preferable that it is 3-9N / 10mm. Among these, 4 to 8 N / 10 mm is particularly preferable.

(Configuration of shading reflection tape of the present invention)
A specific embodiment of the light-shielding reflective tape of the present invention will be described with reference to the attached drawings.

  FIG. 1 shows an embodiment in which a pressure-sensitive adhesive layer 4 is laminated on the light shielding layer 2 side of a support 3 in which a light reflecting layer 1 and a light shielding layer 2 are laminated. In this configuration, the light reflecting layer 1 contains a color former. FIG. 2 shows an embodiment in which an adhesive layer 4 is laminated on the light reflecting layer 1 side of a support 3 in which the light reflecting layer 1 and the light shielding layer 2 are laminated. In this configuration, a color former may be contained in either the light reflection layer 1 or the pressure-sensitive adhesive layer 4. FIG. 3 is an embodiment showing an example of the light-shielding reflective tape of the present invention in which the pressure-sensitive adhesive layer 4 is provided on both surfaces of the support 3 in which the light reflecting layer 1 and the light-shielding layer 2 are laminated. In the said structure, the color former should just contain in the at least one of the adhesive layer 4 laminated | stacked on the light reflection layer 1 or the light reflection layer 1. FIG. The light-shielding reflective tape of the present invention can take the form of a single-sided light-shielding reflective tape as shown in FIGS. 1 and 2 or a double-sided light-shielding reflective tape as shown in FIG. The pressure-sensitive adhesive layer 4 may be a single-layer pressure-sensitive adhesive layer, or may be a multilayer material composed of a plurality of pressure-sensitive adhesive layers and sheets such as double-sided tape.

  FIG. 4 shows a pressure-sensitive adhesive layer 4 on both sides of a support in which a light-reflecting layer 1 made of white ink or the like and a light-shielding layer 2 made of black ink or the like are provided in this order on one surface of a transparent substrate layer 5 made of a transparent resin film. Is a light-shielding reflective adhesive tape. In the said structure, the color former may contain in at least one of the adhesive layer 4 laminated | stacked on the light reflection layer 1 or the transparent base material layer 5. FIG. FIG. 5 shows a transparent substrate layer 5 made of a transparent resin film on one side of a support having a light reflecting layer 1 made of white ink or the like and a light shielding layer 2 made of black ink or the like on the other side. A light-shielding reflective adhesive tape provided with an adhesive layer. In the said structure, the color former should just contain in the at least one of the adhesive layer 4 laminated | stacked on the light reflection layer 1 or the light reflection layer 1. FIG.

  Embodiments shown in FIGS. 6 to 8 can be exemplified as a configuration having a color developing layer containing a color former. FIG. 6 is an embodiment having a color former layer 6 between the light reflecting layer 1 and the pressure-sensitive adhesive layer 4 in the configuration shown in FIG. FIG. 7 shows an embodiment in which the color former layer 6 is provided between the light reflecting layer 1 and the pressure-sensitive adhesive layer 4 in the configuration shown in FIG. FIG. 8 shows an embodiment having a color former layer 6 between the light reflecting layer 1 and the pressure-sensitive adhesive layer 4 in the configuration shown in FIG.

  It is preferable that the light-shielding reflective tape of this invention is a light-shielding reflective tape which has an adhesive layer on both surfaces as illustrated by FIGS. In the case of a double-sided adhesive tape, the LCD panel can be fixed to the backlight housing without using components for preventing the LCD panel from being detached from the backlight housing.

(Coloring method)
The light-reflecting reflective tape of the present invention can control light reflectivity by partially applying light or heat to the reflective surface side in a processing step after tape production. The position, range, and density of color development can be individually adjusted according to the LCD module model.

  The color development method is not particularly limited, but it is preferable to use a laser beam capable of precise color development position, range and density. Examples of the laser light include solid lasers such as a ruby laser and a YAG laser, and gas lasers such as a carbon dioxide gas laser and a helium neon gas laser. The FAYb method in which laser amplification is performed in an ytterbium-doped fiber may be used. Among them, the wavelength of 1064 nm of YAG laser light, which generates a small amount of heat and has little influence on the adhesive, is most preferable. In order to avoid damage to the light shielding layer, it is preferable to irradiate the laser in two or more times with a weak output. Moreover, when irradiating an adhesive tape with a laser, in order to prevent the release film from being excited, it is preferable to peel the release film and directly irradiate the adhesive surface.

  When the light-shielding reflective tape of the present invention is used in a shape punched into a frame shape in an LCD module, it is preferable that the color is developed in the following pattern according to the purpose. For example, when the unevenness on the three sides other than the LED side becomes a problem, it is preferable to cause the three sides other than the LED side to develop a dark color as shown in FIG. In addition, when there is light unevenness in the vicinity of the LED, the effect of suppressing luminance unevenness is high by forming the color developing portion 7 in the peripheral portion of the light source position 8, so that the light source position 8 of the LED and the image display portion as shown in FIG. In the meantime, it is preferable that an island-shaped pattern is formed by the coloring portion 7 or a line-shaped pattern is formed by the coloring portion 7 between the light source position 8 and the image display portion as shown in FIG.

(How to use with LCD module)
The light-shielding / reflecting tape having both the light-reflecting property and the light-shielding property of the present invention can be exemplified by a preferred embodiment in which the frame is punched and sandwiched between the LCD panel 17 and the backlight housing 16. It is affixed at the position of “light-shielding reflective tape 10” shown in FIG. The light-shielding pressure-sensitive adhesive tape of the present invention applied in this form can be exemplified by a preferred embodiment in which the frame is punched and sandwiched between the LCD panel 17 and the backlight housing 16. At that time, the light shielding layer 2 of the light shielding reflective tape of the present invention is in contact with the backlight housing 16 and the prism sheet 11 so that the light shielding layer 2 is in the direction of the LCD panel 17 and the light reflecting layer 1 is in the direction of the light source 13. Adhere to. At that time, when the light-shielding reflective tape of the present invention is a double-sided light-shielding reflective tape, it is attached to the LCD panel 17 and the backlight housing 16. In the case of a single-sided light-shielding reflective tape, the tape is attached to the LCD panel 17 or the backlight housing 16. When the light-shielding reflective tape of the present invention is a single-sided light-shielding reflective tape, the LCD panel is fixed to the backlight housing 16 with parts such as a presser. Since the light-shielding reflective tape of the present invention is also excellent in light reflectivity and light-shielding property, the light from the light source 13 can be effectively reflected to the LCD panel 17 side, and light can enter the driving driver 9. Can be prevented.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto. In addition, the part displayed below is a mass part.

[Production example of polyester urethane]
(Polyester urethane resin A)
Number average molecular weight obtained from acid component of adipic acid / terephthalic acid = 50/50 and trimethyl-1,5-pentanediol (below) in a four-flask equipped with stirrer, thermometer, reflux condenser and nitrogen gas introduction tube 256.3 parts of 2,000 polyester diol (referred to as Mn) and 36.5 parts of isophorone diisocyanate were charged and reacted at 90 ° C. for 15 hours under a nitrogen stream. Next, 5.0 parts of isophoronediamine, 2.2 parts of di-n-butylamine, 175 parts of toluene, 350 parts of methyl ethyl ketone, and 175 parts of isopropylene alcohol were added and reacted under a stirring frame at 40 ° C. for 3 hours to obtain a resin solid content. A polyester urethane resin A having a concentration of 30.0%, a Gardner viscosity UV (25 ° C.), an amine value of 0, and a mass average molecular weight (hereinafter referred to as Mw) of 67,000 was obtained. The obtained resin had a tan δ peak temperature of -8 ° C.

[Black ink production example 1]
4 parts of Degussa “Carbon Degussa Special 4A”, 6 parts of Degussa “Carbon Special 250P”, 40 parts of polyester urethane resin A (tan δ peak temperature = −8 ° C.), 23 parts of methyl ethyl ketone, 13 parts of toluene Then, 6 parts of ethyl acetate, 3 parts of N-propyl acetate and 3 parts of isopropyl alcohol were added, and the mixture was wet-dispersed with a sand mill for about 1 hour, and then a curing agent “KR90” (hexuremethylene didiisocyanate biuret body) ) And 35 parts of DIC's diluent “Direducer V No. 20” were added to prepare black ink B. In addition, resin represents solid content ratio.

[Production Example 1 of white ink]
25 parts of “R830” manufactured by Ishihara Sangyo Co., Ltd., 40 parts of polyester urethane resin A (tan δ peak temperature = −8 ° C.), 23 parts of methyl ethyl ketone, 13 parts of toluene, 6 parts of ethyl acetate, 3 parts of N-propyl acetate 3 parts of isopropyl alcohol and 4 parts of DIC's curing agent “KR90” (biuret of hexamethylene didiisocyanate), DIC's diluent “Direducer” White ink W was prepared by adding 35 parts of “V No. 20”. In addition, resin represents solid content ratio.

(Laser color former A)
24 parts of copper (II) oxide, 29 parts of molybdenum trioxide (VI) (both manufactured by Wako Pure Chemical Industries, Ltd.) and 100 parts of silica particles (manufactured by Fuji Cycilia) were mixed and dry-mixed with a small pulverizer. The mixed powder was fired at a temperature of 700 ° C. in an electric furnace. The fired powder was pulverized in a mortar to obtain a laser color former A.

(Ink A containing laser color former A)
25 parts of laser color former A, 40 parts of polyester urethane resin A (tan δ peak temperature = −8 ° C.), 23 parts of methyl ethyl ketone, 13 parts of toluene, 6 parts of ethyl acetate, 3 parts of N-propyl acetate, isopropyl 3 parts of alcohol was added, and 4 parts of a curing agent “KR90” (biuret of hexamethylene didiisocyanate) manufactured by DIC was added to a product which was wet-dispersed with a sand mill for about 1 hour, and a diluent “Direducer V No. Ink A containing laser colorant A was prepared by adding 35 parts of 20 ". In addition, resin represents solid content ratio.

(Preparation of base material)
Both sides of the white polyester film “E20 # 38” manufactured by Toray Industries, Inc. were subjected to corona treatment so that the wetting tension was 50 dynes / cm, and white ink W was gravure coated twice on one surface so that the dry thickness was 2 μm. Further, black ink B was gravure-coated twice on white ink so that the dry thickness was 4 μm.
The film was further cured at 40 ° C. for 2 days to obtain an ink coat film (a).

  The ink film containing the laser color former A was gravure coated once on the polyester film surface of the ink coat film (a) so that the dry thickness was 2 μm. The film was further cured at 40 ° C. for 2 days to obtain an ink coat film (b).

(Preparation of acrylic copolymer 1)
In a reaction vessel equipped with a condenser, a stirrer, a thermometer, and a dropping funnel, 93.4 parts of n-butyl acrylate, 3.5 parts of acrylic acid, 0.1 part of β-hydroxy-ethyl acrylate, and 2, as a polymerization initiator 0.2 part of 2′-azobisisobutylnitrile was dissolved in 100 parts of ethyl acetate, purged with nitrogen, and then polymerized at 80 ° C. for 8 hours to obtain an acrylic copolymer 1 having a mass average molecular weight of 800,000.

(Preparation of acrylic pressure-sensitive adhesive composition 1)
100 parts of the above-mentioned acrylic copolymer 1, 10 parts of "Superester A100" manufactured by Arakawa Chemical Co., Ltd. and 10 parts of "Pencel D135" manufactured by Arakawa Chemical Co., Ltd. are diluted with toluene, and an acrylic adhesive having a solid content of 40% is diluted. Agent composition 1 was obtained.

Example 1
(Production of double-sided tape)
After 10 parts of the laser color former A is blended into the acrylic pressure-sensitive adhesive composition 1 and 1.5 parts of “Coronate L-45” (isocyanate-based cross-linking agent) manufactured by Nippon Polyurethane Industry Co., Ltd. is stirred sufficiently, On the polyester film having a thickness of 75 μm subjected to the release treatment, coating was performed so that the thickness after drying was 20 μm, and drying was performed at 100 ° C. for 2 minutes to obtain an adhesive layer. This is transferred to the white surface of the ink coat film (a). Next, 1.5 parts of “Coronate L-45” (isocyanate-based cross-linking agent) manufactured by Nippon Polyurethane Industry Co., Ltd. was blended into the acrylic pressure-sensitive adhesive composition 1, and after sufficiently stirring, the thickness was 75 μm after the mold release treatment. On the polyester film, it was coated so that the thickness after drying was 20 μm, and dried at 100 ° C. for 2 minutes to obtain an adhesive layer. This pressure-sensitive adhesive layer was laminated on the black surface side with a hot roll at 80 ° C. at a pressure of 4 kgf / cm, and further cured at 40 ° C. for 2 days to obtain a double-sided tape.

(Example 2)
The acrylic pressure-sensitive adhesive composition 1 is blended with 1.5 parts of “Coronate L-45” (isocyanate-based cross-linking agent) manufactured by Nippon Polyurethane Industry Co., Ltd., sufficiently stirred, and then subjected to a release treatment to obtain a 75 μm thick polyester film. On top, it was coated so that the thickness after drying was 20 μm, and dried at 100 ° C. for 2 minutes to obtain an adhesive layer. This was transferred to both sides of the ink coat film (b), laminated with a 80 ° C. hot roll at a pressure of 4 kgf / cm, and further cured at 40 ° C. for 2 days to obtain a double-sided tape.

(Comparative Example 1)
A double-sided tape was obtained in the same manner as in Example 2 except that the ink coat film (a) was used instead of the ink coat film (b).

  About the double-sided tape created by the Example and the comparative example, the total light transmittance, the total reflectance, adhesive force, tape thickness, average brightness, Hikarimura were evaluated by the method shown below. The evaluation results are shown in Tables 1 and 2.

(Total light transmittance, total reflectance)
Total light transmittance and total reflectance were measured using HR-100 manufactured by Murakami Color Research Laboratory. In addition, the D65 light source was used for the light source, and the total reflectance measured the value after blank and laser irradiation.
The laser used was a FAYb laser “LPV-10U” (manufactured by SUNX), and the release film was peeled off on the reflective surface side of the double-sided tape and irradiated with pulsed laser light having a wavelength of 1064 nm and an average output of 3.6 W. did.

(Adhesive strength)
The adhesive strength was determined by the following procedure in accordance with the JIS-Z0237 (2000) 180-degree peeling adhesive strength test method.
A 20 mm wide light-reflective tape of Example and Comparative Example lined on a SUS plate with a polyester film of 25 μm was pressed once with a 2 kg roller under an ambient temperature of 23 ° C. and a humidity of 50%, and left for 1 hour. , Tensilon universal tensile tester (Orientec Ltd., RTA100) used, and pulled at a rate of 300mm / min, the same temperature and humidity conditions, to measure the 180 degree peel adhesion _{S 20.}

(Tape thickness)
The thickness of the double-sided tape was measured with a thickness meter. The case where the thickness was 100 μm or less was regarded as suitable.

(Average brightness)
1) Using a FAYb laser “LPV-10U” (manufactured by SUNX) at a predetermined position of the double-sided tapes of Examples and Comparative Examples, the release film is peeled off on the reflective surface side of the double-sided tape, and the wavelength is 1064 nm. A pulsed laser beam with an average output of 3.6 W was irradiated. Further, punching was performed to produce a frame-shaped tape processed product as shown in FIG.
2) Next, an LED backlight having an average luminance of 6232 cd / m ² (Minebea Co., Ltd., 2.2-inch mobile phone backlight (LED; Nichia Chemical NSSW020A 4 lights, prism sheet; Downward Prism) was installed. The reflective surface of the tape processed product was bonded to the backlight housing of the LCD module so that the reflective surface was on the backlight housing side.
3) The screen was divided into nine parts with a luminance meter “eye scale 3” manufactured by Eye System Co., Ltd., and the luminance at each central position was measured. The driving condition was If = 15 mA. The measurement environment was a room temperature of 23 ° C. and a humidity of 50%. The average luminance was an average value of 9 points.
A sample having an average luminance exceeding 6400 cd / m ² was judged good.

(Hikarimura at the end)
Looking at the backlight, the presence or absence of light spots on the three sides other than the LED side of the light-shielding reflective tape was visually determined. The LED side was ignored because it was inconspicuous when incorporated into an actual mobile phone.
○: No Hikarimura ×: Hikarimura

  As is clear from the results shown in Table 1, the light-shielding reflective tape of the example has no light spot unevenness at the end because the reflectance is partially controlled by a laser when incorporated in the backlight module, and High average brightness was shown. Moreover, since the reflectance is controlled by a laser during processing after the double-sided tape is made, the degree of freedom in product design is extremely high. On the other hand, the tape of Comparative Example 1 has a high average luminance, but has an uneven edge.

It is sectional drawing which shows an example of the adhesive tape of this invention which provided the adhesive layer 4 in the light shielding layer 2 side of the support body 3 which laminated | stacked the light reflection layer 1 and the light shielding layer 2. FIG. It is sectional drawing which shows an example of the adhesive tape of this invention which provided the adhesive layer 4 in the light reflection layer 1 side of the support body 3 which laminated | stacked the light reflection layer 1 and the light shielding layer 2. FIG. It is sectional drawing which shows an example of the adhesive tape of this invention which provided the adhesive layer 4 on both surfaces of the support body 3 which laminated | stacked the light reflection layer 1 and the light shielding layer 2. FIG. An example of the pressure-sensitive adhesive tape of the present invention in which a pressure-sensitive adhesive layer 4 is provided on both surfaces of a support 3 in which a light reflecting layer 1 and a light-shielding layer 2 are provided in this order on one surface of a transparent substrate layer 5 made of a transparent resin film. FIG. According to the present invention, the light reflecting layer 1 is provided on one surface of the transparent substrate layer 5 made of a transparent resin film, and the pressure-sensitive adhesive layer 4 is provided on both surfaces of the support 3 provided with the light shielding layer 2 on the other surface. It is sectional drawing which shows an example of an adhesive tape. An example of the pressure-sensitive adhesive tape of the present invention in which the pressure-sensitive adhesive layer 4 is provided on both surfaces of the support 3 in which the light reflection layer 1 and the light-shielding layer 2 are laminated, and the color former layer 6 is provided between the light reflection layer 1 and the pressure-sensitive adhesive layer 4. FIG. An adhesive layer 4 is provided on both sides of a support 3 provided with a light reflecting layer 1 and a light shielding layer 2 in this order on one surface of a transparent substrate layer 5 made of a transparent resin film, and the light reflecting layer 1 and the adhesive are provided. It is sectional drawing which shows an example of the adhesive tape of this invention which provided the color former layer 6 with the structure laminated | stacked on the transparent base material layer 5 between the layers 4. FIG. A light reflecting layer 1 is provided on one surface of a transparent substrate layer 5 made of a transparent resin film, and an adhesive layer 4 is provided on both surfaces of a support 3 provided with a light shielding layer 2 on the other surface. It is sectional drawing which shows an example of the adhesive tape of this invention which provided the color former layer 6 between the adhesive layer 4 and the adhesive layer. It is a figure which shows an example of the light-shielding reflective tape which stamped the image display part in the shape of a frame, and made three sides other than the light source side color. It is a figure which shows an example of the light-shielding reflective tape which stamped the image display part in frame shape, and formed the pattern which made the island-shaped dark color between the light source position and the image display part. It is a figure which shows an example of the light-shielding reflective tape which stamped the image display part in frame shape, and formed the pattern made to color in the dark color between the light source position and the image display part. 2 is a cross-sectional view of an LCD module in which components such as an LCD panel 17 are fixed to a backlight housing 16 using a light-shielding reflective tape 10. FIG.

1: Light reflecting layer 2: Light shielding layer 3: Support body 4: Adhesive layer 5: Transparent base material layer 6: Color developing layer 7: Color developing part 8: Light source position 9: Driver 10: Light shielding reflective tape 11: Prism sheet 12: Diffusion Sheet 13: Light source 14: Light guide plate 15: Reflector plate 16: Backlight housing 17: LCD panel 100: LCD module

Claims (6)

A light-shielding reflective tape used by being stuck between the LCD panel of the LCD module and the backlight housing,
A support having at least a light shielding layer and a light reflection layer, and a pressure-sensitive adhesive layer provided on the light reflection layer side of the support,
The light reflecting layer or pressure-sensitive adhesive layer contains a color former that develops color by light or heat, or a color that contains a color former that develops color by light or heat between the light reflective layer and the pressure-sensitive adhesive layer. A light-shielding reflective tape comprising a layer. 2. The light-shielding reflective tape according to claim 1, wherein the color former that develops color by light or heat is a laser color former that produces color by a laser. The support has a light-shielding layer composed of a black print layer and a light-reflective layer composed of a white print layer on one surface of a base material layer composed of a transparent resin film. The light-shielding reflective tape according to claim 1, which is a support having an outer layer. The support is a support having a light-shielding layer made of a black print layer on one surface of a base material layer made of a transparent resin film and a light reflecting layer made of a white print layer on the other surface. Item 3. The light-shielding reflective tape according to Item 1 or 2. The light-shielding reflective tape according to claim 1 or 2, wherein the support is a support in which a light-shielding layer made of a black print layer is provided on a light-reflective layer made of a white resin film. An LCD module having an LCD panel and a backlight housing, wherein the LCD panel and the backlight housing are attached with the light-shielding reflective tape according to any one of claims 1 to 5. LCD module.

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