JP3389704B2 - Light guide plate - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light guide plate, and particularly when used in a liquid crystal display, the light guide plate also functions as a light reflecting sheet, a light collecting sheet or a diffusing film. The present invention relates to a light guide plate which can improve productivity of a display and contribute to reduction in thickness, weight and brightness.

[0002]

2. Description of the Related Art A liquid crystal display is a liquid crystal, a liquid crystal alignment film, a transparent electrode, a polarizing film, a retardation film, a light condensing sheet, a diffusion film, a light guide plate, a light reflecting sheet, and many other films having different functions. It is made up of sheets. Since there are many types of films and sheets,
Since the assembly process is complicated, there are restrictions on cost reduction, and as the number of laminated layers increases, the light transmittance decreases and the image becomes dark, so there is a strong demand to reduce the number of sheets used. For example, conventional backlight portion, as shown in FIG. 6, a diffusion film or condensing sheet to the liquid crystal cell side surface of the light guide plate are laminated via an adhesive or an adhesive, the liquid crystal cell side of the light guide plate A light-reflecting sheet is laminated on the surface opposite to that with an adhesive or an adhesive. As described above, since the conventional backlight is composed of a large number of sheets, it is unavoidable that the luminance is deteriorated due to the lamination of the sheets, and it has become difficult to meet the demand for further luminance improvement with the colorization of liquid crystal displays in recent years. It was Further, there are many problems in the film itself which has been widely used as a film having each function which constitutes a backlight in the related art. For example, a light guide plate is usually made of a plate made of polymethylmethacrylate resin (PMMA), but acrylic resin has a heat distortion temperature of about 90 ° C. and a relatively high water absorption rate. There is a problem that the plate may be deformed when used for a long time in a humid environment. The light reflecting sheet is usually polyethylene terephthalate (PE
Sheets colored with a white pigment are mainly used for T), but since PET is inferior in heat resistance and has a relatively high water absorption rate, the sheet is deformed by heat and moisture under high temperature and high humidity, and in some cases, it may be deformed. There was a risk of peeling from the light guide plate. The light-condensing sheet or diffusion film is generally formed by forming a fine pattern on the surface of a transparent sheet or film by embossing or applying a photocurable resin. Sheets or films made of polycarbonate resin (PC) or polyethylene terephthalate (PET) are used as the base material. However, since the film made of PC has a low surface hardness, the film is easily scratched and a fine pattern is formed. There is a problem in that the appearance and transparency of the display are impaired due to the film being damaged during the assembly work of the display and the like. Also PE
A film made of T is inferior in transparency, and a liquid crystal display using such a film has a problem in that it lacks in brightness and an image is difficult to see. In addition, the heat resistance is not sufficient,
It was difficult to form a uniform fine pattern, such as warping of the film during fine pattern formation. As described above, the light guide plate, the light-condensing sheet, and the diffusion film used in the liquid crystal display not only have the problems attributable to the characteristics of the material itself used, but also provide each film with a required function. Therefore, it has been difficult to reduce the number of films despite the strong demand for thinning and lightening of liquid crystal displays.

[0003]

DISCLOSURE OF THE INVENTION The present invention improves the heat resistance and water absorption of PMMA used as a light guide plate, and improves the optical cloth uniformity of a film made of PC or PET used as a light-condensing sheet or a diffusion film. By improving and integrating the functions of the light guide plate and light reflection sheet, light-condensing sheet or diffusion film, the steps such as bonding can be eliminated, the decrease in reliability due to bonding can be eliminated, and the number of films used can be reduced. (EN) Provided is a light guide plate which achieves a reduction in thickness and weight of a liquid crystal display by reduction and an improvement in brightness of a liquid crystal display by improving light transmittance of a laminated film.

[0004]

The present invention is directed to norbornene.
Hydrogenated ring-opening polymer of the system monomer, gel content is
Made of thermoplastic norbornene-based resin of 5% by weight or less
Ri, single-sided liquid crystal display light guide plate, characterized in that has been subjected to light reflection treatment, single-sided light diffusing process or a liquid crystal display light guide plate to a condenser treated that features, has been subjected to light reflection treatment A light guide plate for a liquid crystal display, characterized in that a surface opposite to the surface is subjected to light diffusion processing or light collection processing. Hereinafter, the present invention will be described in detail. 1 to 3 are schematic cross-sectional views of the light guide plate of the present invention . FIG. 1 shows an example in which the light reflection layer 2 is formed on one surface of the light guide plate 1. FIG. 2 shows an example of the light guide plate 1 ′ that has been subjected to the light diffusion process or the light collection process. FIG. 3 shows an example in which the light reflection layer 2 is formed on the surface of the light guide plate 1 ′ that has been subjected to the light diffusion processing or the light collection processing, opposite to the processing surface . In the light guide plate of the present invention
For, a thermoplastic norbornene-based resin is used. Thermoplastic
The norbornene-based resin has high transparency, is optically uniform, and is excellent in heat resistance and moisture resistance. Therefore, a light-diffusing pattern or a light-condensing pattern is directly formed on the light guide plate surface as in the present invention. However, it is preferable because an optically uniform pattern can be obtained, and even if it is used for a long time under the condition of high temperature and high humidity, the plate is not deformed and a highly reliable light guide plate can be obtained.
4 is a backlight using the light guide plate of the present invention of FIG.
FIG. 5 is a schematic cross-sectional view showing an example of the invention, and FIG.
Schematic cross-sectional view showing an example of a backlight using the light guide plate of
Is.

The thermoplastic norbornene-based resin used in the present invention has a norbornane skeleton in its repeating unit. For example, as this thermoplastic resin,
It contains a norbornane skeleton represented by the general formulas (I) to (IV).

[0006]

[Chemical 1]

[0007]

[Chemical 2]

[0008]

[Chemical 3]

[0009]

[Chemical 4]

(In the formula, A, B, C and D represent a hydrogen atom or a monovalent organic group.) The thermoplastic resin having a norbornane skeleton used in the present invention is required to have sufficient strength. , Its weight average molecular weight is 5,000 to 100
10,000, preferably 8,000 to 200,000. Examples of the thermoplastic resin having a norbornane skeleton that can be used in the present invention include, for example, JP-A-60-168708.
JP-A-62-252406, JP-A-62-252406
-252407, JP-A-2-133413, JP-A-63-145324, JP-A-63-2.
Resins described in JP-B No. 64626, JP-A No. 1-240517, JP-B No. 57-8815 and the like can be mentioned. Among these resins, the present invention
Thermoplastic norbornene resin used in are the amorphous polymer of a ring-opening polymer of a norbornene monomer resin obtained by hydrogenating, easily be optically uniform light guide plate
can get. Generally, a thermoplastic norbornene-based resin is a resin having excellent optical properties, heat resistance, and moisture resistance, but when the light guide plate of the present invention is used in a harsh environment such as an in-vehicle liquid crystal display, it can be used for a long time to improve the optical properties. In order to prevent deterioration, it is desirable to specify the glass transition temperature (Tg) and the saturated water absorption rate of the resin, and it is preferable that the Tg is 120 ° C. or higher and the saturated water absorption rate is 1.0% or lower.
In the present invention, T of a thermoplastic resin having a norbornane skeleton having a structure represented by the above general formulas (I) to (IV)
The g and the saturated water absorption can be controlled by the types of the substituents A, B, C and D and the type of R'in the case of an ester group. Specific examples of this thermoplastic resin are obtained by metathesis polymerization of at least one tetracyclododecene derivative represented by the following general formula (V) or an unsaturated cyclic compound copolymerizable with the tetracyclododecene. The hydrogenated polymer obtained by hydrogenating the obtained polymer can be mentioned.

[0011]

[Chemical 5]

(In the formula, A to D are the same as above.) In the tetracyclododecene derivative represented by the general formula (V), it is possible that A, B, C and D contain a polar group. It is preferable in terms of adhesion with and heat resistance.
Further, the polar group is — (CH ₂ ) nCOOR ³ (wherein R ³ is a hydrocarbon group having 1 to 20 carbon atoms, and n is 0 to 10).
It is preferable that the hydrogenated polymer obtained is a group represented by the formula (1), which has a high glass transition temperature. In particular, the - (CH ₂₎ a polar substituent represented by NCOOR ^3, it contained one per molecule of tetracyclododecene derivatives of general formula (V) is preferable from the viewpoint of reducing the water absorption. In the general formula,
R ³ is a hydrocarbon group having 1 to 20 carbon atoms, but it is preferable that the number of carbon atoms increases as the hygroscopic property of the obtained hydrogenated polymer decreases. However, R ³ has a glass transition temperature of the obtained hydrogenated polymer. From the viewpoint of balance, a chain alkyl group having 1 to 4 carbon atoms or a (poly) cyclic alkyl group having 5 or more carbon atoms is preferable, and a methyl group, an ethyl group and a cyclohexyl group are particularly preferable.

Further, the carbon atom to which the group represented by-(CH ₂ ) _n COOR ³ is bonded simultaneously has 1 to 10 carbon atoms.
The tetracyclododecene derivative represented by the general formula (V) in which the hydrocarbon group is bonded as a substituent reduces hygroscopicity and is therefore preferable. In particular, the tetracyclododecene derivative represented by the general formula (V) in which the substituent is a methyl group or an ethyl group is preferable because the synthesis thereof is easy. Specifically, 8-methyl-8-methoxycarbonyltetracyclo [4,4,0,1 ^2.5 1 ^7.10] dodeca-8-ene are preferred. These tetracyclododecene derivatives or a mixture of unsaturated cyclic compounds copolymerizable therewith are described, for example, in JP-A-4-77520, page 4, upper right column, line 12 to page 6, lower right column, line 6. The thermoplastic resin used in the present invention can be obtained by metathesis polymerization and hydrogenation according to the method described above. In the present invention, the thermoplastic resin having a norbornane skeleton has an intrinsic viscosity (η _inh ) measured at 30 ° C. in chloroform of 0.2 to 1.5 dl.
/ G, preferably 0.3 to 1.0 dl / g. When the intrinsic viscosity (η _inh ) is less than 0.2 dl / g, the mechanical properties are poor and the impact resistance is lowered, while when it exceeds 1.5 dl / g, the workability is poor and the film formability is poor. The hydrogenation rate of the hydrogenated polymer is 60 MHz, and the value measured by ¹ H-NMR is 50% or more, preferably 90% or more, more preferably 98% or more. The higher the hydrogenation rate, the better the stability to heat and light . The hydrogenated polymer used as the thermoplastic resin having a norbornane skeleton in the present invention has a gel content of 5 % by weight from the viewpoint of preventing the occurrence of defects such as silver streak in the molding of a molded plate. % Or less, particularly preferably 1% by weight or less
is there.

In the present invention, the thermoplastic norbornene-based resin includes known antioxidants such as 2,6-di-t-butyl-4-methylphenol and 2,2'-dioxy-.
3,3'-di-t-butyl-5,5'-dimethylphenylmethane, tetrakis [methylene-3- (3,5-di-
t-butyl-4-hydroxyphenyl) propionate] methane, 1,1,3-tris (2-methyl-4-hydroxy-5-t-butylphenyl) butane, 1,3,3
5-trimethyl-2,4,6-tris (3,5-di-t
-Butyl-4-hydroxybenzyl) benzene, stearyl-β- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, 2,2'-dioxy-3,
3'-di-t-butyl-5,5'-diethylphenylmethane, 3,9-bis [1,1-dimethyl-2- [β-
(3-t-Butyl-4-hydroxy-5-methylphenyl) propionyloxy] ethyl], 2,4,8,10
-Tetraoxpyro [5,5] undecane, tris (2,4-di-t-butylphenyl) phosphite, cyclic neopentanetetraylbis (2,4-di-)
t-Butylphenyl) phosphite, cyclic neopentanetetraylbis (2,6-di-t-butyl-4)
-Methylphenyl) phosphite, 2,2-methylenebis (4,6-di-t-butylphenyl) octylphosphite; UV absorbers such as 2,4-dihydroxybenzophenone and 2-hydroxy-4-methoxybenzophenone It can be stabilized by adding it. Further, additives such as a lubricant may be added for the purpose of improving processability. The amount of these antioxidants added is usually 0.1 to 100 parts by weight of the specific polymer.
3 parts by weight, preferably 0.2 to 2 parts by weight. When the amount of the antioxidant used is too small, the effect of improving the durability is insufficient, and when it is too large, problems such as bleeding from the molding surface and deterioration of transparency are unfavorable.

The light guide plate of the present invention can be obtained by molding the above-mentioned resins by known methods such as injection molding, injection compression molding and extrusion molding. Further, there is no particular limitation on the method of forming a pattern having a light diffusing or condensing function on the light guide plate, and the surface of the light guide plate obtained by the above method is coated with an embossing or a photocurable resin such as ultraviolet rays and cured. The above pattern may be formed by the above, or a light diffusing function may be provided by a coating material. When a mold is used, a desired pattern is previously formed on the mold surface, and the light guide plate is molded. The pattern may be transferred at the same time. The thickness of the light guide plate obtained as described above is not particularly limited, but is 0.05 to 5 mm.
It is preferably in the range of. On this light guide plate, a light reflecting layer can be formed on the surface opposite to the pattern forming surface having a light diffusing function or a light collecting function, but the method for forming the light reflecting layer is not particularly limited. It may be applied or printed over the entire surface, and in order to make the brightness of the light guide plate constant irrespective of the location of the light source, for example, any shape, area, such as dots, lines, or comb teeth It may be printed in a pattern having a distribution.
As the paint used for the light reflection layer, a white pigment containing an inorganic pigment such as titanium oxide as a main component is preferably used. Further, by covering the side surface of the light guide plate other than the light incident surface with the white paint or the mirror-like reflection layer, it is possible to prevent the light emission port and improve the brightness.

In the light guide plate of the present invention, on the light reflection layer forming surface,
Further, a light reflecting sheet may be laminated. The type of light-reflecting sheet is not particularly limited, and for example, a film obtained by adding a pigment such as titanium oxide, barium sulfate, calcium carbonate, aluminum hydroxide, magnesium carbonate, or aluminum oxide to a plastic resin into a film or sheet by a usual method. A molded product may be used, or a foamed sheet may be used. Further, it is also possible to use a metal plate made of aluminum, gold or the like, or a reflection plate having a mirror surface state such as a plate having a metallic luster by plating or vapor deposition. Among the sheets used for the light reflection sheet, the one using a plastic sheet is not particularly limited as described above, but a sheet made of a material containing a thermoplastic norbornene-based resin has excellent heat resistance and moisture resistance, and has a high temperature and a high temperature. It can be preferably used because it has high reliability without being deformed by heat or moisture and peeling from the light guide plate even under severe conditions such as humidity. In the present invention, as the light source of the light guide plate, a commonly used light source can be used, and one or a plurality of lamps or cold cathode tubes arranged on one side or both sides of the light guide plate are preferably used. In the light guide plate of the present invention, a light diffusing sheet or a light condensing sheet can be further laminated on the shape surface side having a light condensing function or a light diffusing function.
Known materials can be used for these light diffusion sheet and light-condensing sheet, for example, polyethylene terephthalate,
Polyester such as polyethylene isophthalate and polybutylene terephthalate, acrylic resin such as polymethyl (meth) acrylate and polyethyl (meth) acrylate, polycarbonate, ABS resin, thermoplastic norbornene resin, etc. are embossed on a sheet or film made of a transparent resin. Alternatively, for a light-diffusing sheet or a light-diffusing sheet on which a desired pattern is formed by applying and curing a photocurable resin such as ultraviolet rays, a coating material such as an inorganic pigment or an organic pigment dispersed in a solvent is applied. The thing obtained is mentioned.

A pressure-sensitive adhesive or an adhesive can be used for laminating the above-mentioned light-reflecting sheet, light-condensing sheet, or light-diffusing sheet on the light guide plate of the present invention. As these pressure-sensitive adhesives and adhesives, those having excellent transparency are preferable, and specific examples thereof include natural rubber, synthetic rubber, vinyl acetate / vinyl chloride copolymer, polyvinyl ether, acrylic type, modified polyolefin type, and isocyanate Examples thereof include a curable pressure-sensitive adhesive to which a curing agent such as nato is added, an adhesive for dry lamination in which a polyurethane resin solution and a polyisocyanate resin solution are mixed, a synthetic rubber adhesive, and an epoxy adhesive. Further, in the light guide plate of the present invention, an adhesive layer or an adhesive layer may be previously laminated on the surface in order to improve the workability of assembling the liquid crystal display. As the pressure-sensitive adhesive, the above-mentioned pressure-sensitive adhesive or adhesive can be used. The light guide plate of the present invention is a laminate of a known liquid crystal substrate, a transparent electrode layer, a liquid crystal alignment layer, a gas barrier layer, a hard coat layer, a polarizing film, and a retardation film in addition to the above light diffusion sheet and light collecting sheet. , Can be a liquid crystal display. Liquid crystal displays using the light guide plate of the present invention include in-vehicle liquid crystal displays for mobile phones, digital information terminals, pagers, navigations, liquid crystal monitors, light control panels, OA equipment displays, A
It can be used as a display for V equipment.

[0018]

EXAMPLES The present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples. In the examples, parts and% are based on weight unless otherwise specified. Reference Example 1 (Production of thermoplastic norbornene resin) 8-methyl-8-methoxycarbonyltetracyclo [4,4,0,1 ^2.5, 1 ^7.10] dodeca-3-ene 10
0 g, 60 g of 1,2-dimethoxyethane, 240 g of cyclohexane, 9 g of 1-hexene, and 3.4 ml of a toluene solution of 0.96 mol / liter of diethylaluminum chloride were added to an autoclave having an internal volume of 1 liter. On the other hand, another flask was charged with tungsten hexachloride (0.1%).
05 mol / l 1,2-dimethoxyethane solution 2
0 ml and 0.1 mol / l of paraaldehyde 1,
10 ml of 2-dimethoxyethane solution were mixed. 4.9 ml of this mixed solution was added to the mixture in the autoclave. After sealing, the mixture was heated to 80 ° C. and stirred for 3 hours. After adding a mixed solvent of 1/8 (weight ratio) of 1,2-dimethoxyethane and cyclohexane to the obtained polymer solution to make the polymer / solvent 1/10 (weight ratio),
20 g of triethanolamine was added and stirred for 10 minutes. To this polymerization solution, add 500 g of methanol to 30
Stir for a minute and let stand. The upper layer separated into two layers was removed, methanol was added again, and the mixture was stirred and left standing, and then the upper layer was removed. The same operation was repeated twice, and the obtained lower layer was appropriately diluted with cyclohexane and 1,2-dimethoxyethane to obtain a cyclohexane-1,2-dimethoxyethane solution having a polymer concentration of 10%. 20 g of palladium / silica magnesia [manufactured by JGC Chemical Co., Ltd., amount of palladium = 5]
%] Is added, and the hydrogen pressure in the autoclave is 40 kg / c.
After reacting at 165 ° C. for 4 hours as m ² , the hydrogenation catalyst was removed by filtration to obtain a hydrogenated polymer solution. Also,
To this hydrogenated polymer solution, pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-), which is an antioxidant, is added.
4-hydroxyphenyl) propionate] was added to the hydrogenated polymer in an amount of 0.1%, and then the solvent was removed at 380 ° C. under reduced pressure. Next, the molten resin was pelletized by an extruder under a nitrogen atmosphere, and the intrinsic viscosity was 0.51 dl /
g (30 ° C., in chloroform), a hydrogenation rate of 99.5%, and a thermoplastic resin A having a glass transition temperature of 168 ° C. were obtained.

Each measurement was carried out as follows. Light transmittance (%) It was measured by a spectrophotometer while continuously changing the wavelength in the wavelength range of 400 to 900 nm, and the minimum transmittance was defined as the light transmittance of the film. Heat distortion temperature (° C.) Measured according to ASTM D648. Water Absorption (%) According to ASTM D570, the weight gain was measured by leaving the sample in water at 23 ° C. for 24 hours. Backlight The presence or absence of scratches and the degree of warpage of the film were evaluated according to the following evaluation criteria. ◯: Good appearance with no scratches, warps, or undulations X: Significant scratches, warps, or undulations, unusable for use Moisture resistance After holding for 1000 hours at 80 ° C and 90% relative humidity Moisture resistance was evaluated by the appearance of Bakulite according to the following evaluation criteria. ◯: No deformation such as warpage and uniform light emission x: Deformation such as warpage is notable and cannot be used

Example 1 Using the thermoplastic resin A obtained in Reference Example 1, a mold having a mirror finish was attached to a commercially available injection molding machine, and a resin temperature of 320
A light guide plate having a thickness of 1 mm was formed at a mold temperature of 130 ° C. and a mold temperature of 130 ° C. The obtained light guide plate was excellent in smoothness without scratches due to silver streaks or peeling. A white pigment made of titanium oxide was applied to the entire surface of one surface of the light guide plate to form a light reflection layer. When a light source composed of a cold cathode tube was placed on one side surface of the light guide plate, the brightness was good and it could be used as a backlight. When the moisture resistance of this light guide plate was evaluated by placing it under conditions of 80 ° C. and 90% relative humidity for 1000 hours, the deformed light reflection layer such as warpage did not peel off and it was highly reliable. Comparative Example 1 A mold with double-sided mirror finish was attached to a commercially available injection molding machine using polymethylmethacrylate resin, and a resin temperature of 230 was used.
A light guide plate having a thickness of 1 mm was molded at a temperature of 100 ° C. and a mold temperature of 100 ° C. A polyethylene terephthalate film colored white with titanium oxide was used as a light reflection sheet on one surface of the light guide plate, and 100 parts of an acrylic resin composed of 90% by weight of n-butyl acrylate, 7% by weight of ethyl acrylate and 3% by weight of acrylic acid. Tolylene diisocyanate (3 mol)
Was laminated using a pressure-sensitive adhesive obtained by mixing a cross-linking agent consisting of 2 parts of a 75 wt% ethyl acetate solution of the trimethylolpropane (1 mol) adduct of. When a light source consisting of a cold cathode tube was placed on one side of this light guide plate, the brightness was good and it could withstand use as a backlight. However, when moisture resistance was evaluated under the same conditions as in Example 1, it was found that Deformation occurred and part of the light reflecting sheet was peeled off.

Example 2 Using the thermoplastic resin A obtained in Reference Example 1, a mold having a mirror finish was attached to a commercially available injection molding machine, and the resin temperature was 32 ° C.
A light guide plate having a mold temperature of 130 ° C. and a thickness of 1 mm was molded. Here, on one side of the mold surface, an interval of 6 μ is previously provided by scribing.
A light diffusion pattern was formed by drawing parallel straight lines of m and a depth of 0.5 μm. No scratches due to silver streaks or peeling were observed on the obtained light guide plate. With respect to this light guide plate, the glass transition temperature, the water absorption rate, and the light transmittance of the mirror surface portion were measured. Next, a white pigment made of titanium oxide was applied to the entire surface of the light guide plate opposite to the light diffusion pattern forming surface, and a light source made of a cold cathode tube was installed on one side surface to obtain a backlight.
With respect to this backlight, its appearance (presence of scratches and warps) and moisture resistance were evaluated. The above results are shown in Table 1.

Example 3 Using the thermoplastic resin A obtained in the reference example, 270
The plate was extruded at 330C and 330C to obtain a plate having a thickness of 1 mm. An ultraviolet curable resin composition having the composition shown below was applied to one surface of this plate using an applicator bar having a clearance of 50 μm. Subsequently, a stamper on which a pattern of minute irregularities was previously patterned was pressure-bonded to the ultraviolet curable resin composition and irradiated with 1 J / cm ² of ultraviolet light from the film side to be cured. After curing, the stamper was peeled off to obtain a light guide plate having a light diffusing pattern in the shape of minute irregularities on the surface. UV-curable resin composition Epoxy acrylate 60 g (Kyoeisha Yushi-Kagaku Kogyo Epoxy Ester 3002A) Trimethylol propane triacrylate 25 g (Toagosei Kagaku Kogyo Aronix M-309) Acrylic acid 15 g (Osaka Organic Chemical Industry) Photoinitiator 4 g (Irgacure 184 manufactured by Ciba-Geigy) This light guide plate was evaluated in the same manner as in Example 2. The results are shown in Table 1.

Comparative Example 2 A mold with double-sided mirror finish was attached to a commercially available injection molding machine using polymethylmethacrylate resin, and a resin temperature of 230 was used.
A light guide plate having a thickness of 1 mm was molded at a temperature of 100 ° C. and a mold temperature of 100 ° C. The light transmittance, heat distortion temperature, and water absorption of this light guide plate were measured. Next, a polycarbonate form (manufactured by Teijin Ltd.) as a light diffusing sheet was obtained by passing an embossing roll between pressure rolls, for a thickness of 100 μm, and an embossing depth of 30.
The light transmittance, the heat distortion temperature, and the water absorption were measured for the sheet of μm. The diffusion sheet was laminated on one surface of the light guide plate using the same adhesive as in Comparative Example 1 to obtain a light guide plate having a light diffusion function. Further, the transparency as a light guide plate having a light diffusing function is represented by the synergistic of the light transmittances of the light guide plate and the light diffusing sheet. The light guide plate having the light diffusion function was evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0023]

[Table 1]

[0024]

The light guide plate of the present invention also has the function of a light diffusion sheet or a light collecting sheet, and it is possible to reduce the number of liquid crystal displays, and to reduce the thickness, weight and productivity of liquid crystal displays. It can greatly contribute to the improvement of reliability and brightness. In the present invention, the light guide plate
Hydrogenated ring-opening polymer of norbornene-based monomer,
Because of the use of film gel content is from 5 wt% or less is fat thermoplastic norbornene resin, in particular an optically uniform excellent transparency, that heat resistance, moisture resistance excellent light guide plate You can

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing an example of a light guide plate of the present invention.

FIG. 2 is a schematic cross-sectional view showing an example of a light guide plate of the present invention.

FIG. 3 is a schematic cross-sectional view showing an example of a light guide plate of the present invention.

FIG. 4 is a schematic cross-sectional view showing an example of a backlight using the light guide plate of the present invention.

FIG. 5 is a schematic cross-sectional view showing an example of a backlight using the light guide plate of the present invention.

FIG. 6 is a schematic cross-sectional view showing an example of a backlight using a conventional light guide plate.

[Explanation of symbols]

1 Light guide plate 1'Light guide plate subjected to light diffusion processing or light collection processing 2 Light reflection layer 3 light sources 4 Light reflection sheet 5 Light reflection sheet or condensing sheet 6 Adhesive layer

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G02B 6/00 G02F 1/1335-1/13363 G09F 9/00 G09F 13/18 F21V 8/00

Claims (3)

(57) [Claims] 1. A ring-opening polymer of a norbornene-based monomer
Hydrogenated thermoplastic with a gel content of less than 5% by weight
A light guide plate for a liquid crystal display, which is made of a transparent norbornene resin and has one surface subjected to a light reflection treatment. 2. A ring-opening polymer of a norbornene-based monomer
Hydrogenated, gel containing 5% by weight or less
A light guide plate for a liquid crystal display, which is made of a plastic norbornene resin and has one surface subjected to a light diffusion process or a light collection process. 3. The light guide plate for a liquid crystal display according to claim 1, wherein the surface opposite to the surface subjected to the light reflection processing is subjected to light diffusion processing or light collection processing.