JP3233669B2 - Manufacturing method of light diffusion sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a light diffusion sheet used for a back light source of a liquid crystal display device.

[0002]

2. Description of the Related Art Conventionally, this type of light diffusion sheet is produced by applying a matte transparent paint in which fine particles such as calcium carbonate and silicon dioxide are dispersed on a transparent sheet such as a polyethylene terephthalate (PET) sheet. It is known to use a fogged glass plate.

[0003]

However, in the above-mentioned method, the light transmittance is low because a substance having a different refractive index, such as a binder and fine particles, is dispersed in the coating film and the fine particles themselves absorb light. And the brightness of the liquid crystal display surface cannot be sufficiently obtained. For this reason, it is conceivable to increase the luminous intensity of the light source, but it is not preferable because power consumption and heat generation increase. Further, uneven gloss is likely to occur due to poor dispersion of the paint and convection of the paint during coating and drying. Further, a change in gloss is likely to occur due to a change in coating conditions.

[0004] In the case of the above-mentioned cloudy glass plate, the glass plate is heavy and easily broken, and it is difficult to perform processing such as cutting. In addition, since the matting process is performed by sand spraying or the like, it takes time and effort.

In any of the above, the obtained fine embossed shape is only a monotonous shape determined by a processing method, and the optical characteristics such as light transmittance and diffusion angle of transmitted light have desired values. Can not be controlled.

An object of the present invention is to solve the above-mentioned problems and to provide a method for manufacturing a light diffusion sheet which is easy to manufacture and whose optical characteristics can be easily controlled.

[0007]

In order to solve the above-mentioned problems, a method for manufacturing a light diffusion sheet according to the present invention uses a half-value angle Θ.
Manufacturing method of light diffusion sheet where _H is 10 ° ≦ ° _H ≦ 60 °
The method is to rotate a roll intaglio having a light-diffusible micro-embossed mold formed thereon, and apply a predetermined amount of an ionizing radiation-curable resin liquid to at least a concave portion of the roll intaglio by a coating device. A filling step of filling, and contacting the transparent resin sheet substrate running in synchronization with the rotation direction of the roll intaglio with the ionizing radiation-curable resin liquid filled in the roll intaglio in the filling step, and simultaneously A contact step of pressing the transparent resin sheet substrate against the roll intaglio by a pressing roll, and, while the sheet substrate is in contact with the roll intaglio in the contacting step, between the roll intaglio and the sheet substrate. A curing step of irradiating an ionizing radiation-curable resin liquid with ionizing radiation to cure the liquid, and bringing the sheet base into close contact with the ionizing radiation-curable resin liquid cured in the curing step. And Chakukotei, a cured product and the sheet base material of the ionizing radiation-curable resin liquid in close contact with the contact step and a peeling step of peeling from the roll intaglio, 5000 cps or less the viscosity of the ionizing radiation curing resin liquid Wherein the surface temperature of the roll intaglio is about 15 ° C. to 50 ° C.

[0008]

According to the present invention, since the resin is molded by the roll intaglio having the concave portion, the desired fine embossed shape can be faithfully reproduced. Further, a light-diffusing fine embossed shape is formed on the surface of the transparent resin, and foreign particles are not dispersed inside. Furthermore, while running the sheet substrate of the belt-shaped web, a fine emboss can be formed by a rotary molding method using a roll intaglio, and the molding can be immediately cured by ionizing radiation.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments will be described below with reference to the drawings.
This will be described in more detail. FIG. 1 is a process diagram showing an embodiment of a method for manufacturing a light diffusion sheet according to the present invention, and FIG. 2 is a diagram showing an embodiment of an apparatus for manufacturing a light diffusion sheet according to the present invention. First, a method and an apparatus for manufacturing a light diffusion sheet according to the present embodiment will be briefly described. FIG.
In (A), 1 is a roll intaglio having desired irregularities formed thereon, 2 is a concave portion of the roll intaglio 1, 3 is an ionizing radiation-curable resin liquid, 4 is a sheet substrate, and 5 is a roll in contact with the roll intaglio. A pressing roll for pressing the intaglio 1; a feed roll 6;
7 is a curing device for curing the ionizing radiation-curable resin liquid 3, and 10 is a coating device for applying the ionizing radiation-curable resin liquid 3 to the roll intaglio 1.

The method for manufacturing the light diffusing sheet of this embodiment is as follows.
As shown in FIG. 1, a filling step 101, a contact step 102,
It comprises a curing step 103, a contact step 104, and a peeling step 105. The filling step 101 is a step of rotating the roll intaglio 1 on which the finely embossed mold having light diffusing properties is formed, and filling at least the concave portion 2 of the roll intaglio 1 with the ionizing radiation-curable resin liquid 3. Contact process 10
2 is a step of bringing the transparent resin sheet base material 4 running in synchronization with the rotation direction of the roll intaglio 1 into contact with the ionizing radiation-curable resin liquid 3 filled in the roll intaglio 1 in the filling step 101. In the curing step 103, while the sheet substrate 4 is in contact with the roll intaglio 1 in the contacting step 102, the ionizing radiation-curable resin liquid 3 between the roll intaglio 1 and the sheet substrate 4 is supplied from the curing device 11. This is a step of irradiating with ionizing radiation for curing. The adhesion step 104 is a step of bringing the ionizing radiation-curable resin liquid 3 cured in the curing step 103 into close contact with the sheet substrate 4. Note that the curing step 103 and the contact step 104 usually proceed simultaneously. The peeling step 105 includes:
In this step, the cured product 3a of the ionizing radiation-curable resin liquid 3 and the sheet substrate 4 adhered in the adhesion step 104 are separated from the roll intaglio 1.

Next, an apparatus for manufacturing a light diffusing sheet according to this embodiment will be described in detail mainly with reference to FIG. The roll intaglio 1 is provided with a concave portion 2 having a predetermined shape, which will be described later, in a cylindrical plate material. This roll intaglio 1
It can be manufactured by directly laminating a cylindrical plate material, cutting by milling with a mill formed by electroforming, electroforming, or the like. Examples of the material of the roll intaglio 1 include metals such as copper, chromium and iron, synthetic resins such as NBR, epoxy and ebonite, and ceramics such as glass. Also, the size of the roll intaglio 1 is not particularly limited,
It can be appropriately selected according to the size of the sheet having the uneven surface to be manufactured. Although not shown,
The roll intaglio 1 is provided with a driving device and is formed so as to rotate.

As described above, as a method of adjusting the viscosity of the resin liquid 3 to a predetermined value, as shown in FIG. A method in which a fluid such as water, oil, steam or the like whose temperature has been adjusted to the above-mentioned temperature is flowed in and out to control the plate surface temperature of the roll intaglio 1A to 1D to a predetermined value can be applied. Generally, the viscosity decreases as the temperature increases, but if the temperature is too high, decomposition and evaporation of the resin liquid 3 occurs.
C. to 50 C. are preferred.

Here, as shown in FIG. 12A, in order to make the fluid flow in and out, as shown in FIG.
a method of flowing a fluid from one side to the other side of FIG.
As shown in (B), a feed pipe 1b is provided inside the roll intaglio 1B.
And the fluid sent to the back of the roll intaglio 1B by the feed pipe 1b is returned along the inner wall of the roll intaglio 1B,
As shown in FIG. 12C, an inner tube 1c having a substantially similar shape to the roll intaglio 1C is provided inside the roll intaglio 1C.
A method of passing a fluid between C and the inner pipe 1c, or as shown in FIG. 12D, an opening 1e [FIG.
(E) is inserted, and the fluid jetted from the opening 1e of the feed pipe 1d is rolled into the roll intaglio 1D.
Back along the inner wall of the car. In this case, in order to uniformly adjust the temperature of the plate surface, a roll intaglio 1D
Is preferred.

As the ionizing radiation-curable resin liquid 3, a composition in which a prepolymer, an oligomer and / or a monomer having a polymerizable unsaturated bond or an epoxy group in a molecule is appropriately mixed can be used. As the prepolymer and oligomer, unsaturated polyesters such as a condensate of an unsaturated dicarboxylic acid and a polyhydric alcohol, an epoxy resin,
Examples include methacrylates such as polyester methacrylate, polyether methacrylate, polyol methacrylate, and melamine methacrylate, and acrylates such as polyester acrylate, epoxy acrylate, urethane acrylate, polyether acrylate, polyol acrylate, and melamine acrylate.

In addition, the monomers include styrene, α
Styrene monomers such as methylstyrene, acrylates such as methyl acrylate, 2-ethylhexyl acrylate, methoxyethyl acrylate, butyl acrylate, etc., methyl methacrylate, ethyl methacrylate, methoxyethyl methacrylate , Methacrylates such as ethoxymethyl methacrylate, acrylic acid-2-
Substituted amino alcohol esters of unsaturated acids such as (N, N-diethylamino) ethyl, unsaturated carboxylic acid amides such as acrylamide and methacrylamide, dipropylene glycol diacrylate, ethylene glycol acrylate, propylene glycol dimethacrylate, diethylene glycol dimethacrylate Polyfunctional compounds such as vinylpyrrolidone, and / or polythiol compounds having two or more thiol groups in the molecule, for example,
Trimethylolpropane trithioglycolate, trimethylolpropane trithiopropylate, pentaerythritol tetrathioglycol and the like can be mentioned.

In particular, when the composition is cured by ultraviolet rays, acetophenones, benzophenones, Michler benzoyl benzoate, α-amyloxime ester, tetramethyl meuram are used as photopolymerization initiators in the ionizing radiation-curable resin composition. Monosulfide, thioxanthones, and / or n-butylamine, triethylamine, tri-n-butylphosphine, and the like as a photosensitizer may be used in combination. Further, in order to faithfully follow the shape of the roll intaglio 1 having the fine concave portions 2 as in this embodiment, the viscosity should be 5000 cps or less, especially 100 cps.
It is preferred to be 0 cps or less.

The sheet base 4 is made of a resin sheet having transparency and ionizing radiation permeability. The thickness of the sheet base 4 is easy to process into a fine embossed shape, and the liquid crystal display element to be used is light and thin. In view of the above, those having a range of about 200 to 12 μm are preferably used. As the material of the sheet base material 4,
Polyester such as polyethylene terephthalate, polyethylene naphthalate, polymethyl methacrylate, polymethyl acrylate, polyethyl methacrylate,
Examples thereof include polymers of methacrylic acid or acrylate such as polyethyl acrylate (so-called acrylic resin), polycarbonate, cellulose triacetate, polystyrene, and polypropylene. It is preferable that the surface of the sheet substrate 4 be subjected to an easy adhesion treatment such as a corona discharge treatment as necessary.

The pressing roll 5 only needs to be able to press the sheet substrate 4, and is usually about 140 mm in diameter, and can be formed of silicon rubber, NBR, EPT or the like. The press roll 5 and the feed roll 6 are rotatable to feed the sheet substrate 4. They are,
It may be of a type in which it rolls with the intaglio plate 1, but it can also be driven by a driving device. It is also possible to provide a sheet feeding device for feeding the sheet base material 4 and a winding device for winding the sheet on which the fine emboss is formed.

The curing device 7a irradiates ionizing radiation,
This is an apparatus for curing the ionizing radiation-curable resin liquid 3. A curing device 7b may be provided to completely cure the detached ionizing radiation-curable resin liquid 3a. here,
Ionizing radiation means, among electromagnetic waves or charged particle beams, those having energy quanta capable of polymerizing and cross-linking molecules, and ultraviolet rays, electron beams and the like are usually used. Curing device 7
In the case of ultraviolet light, a light source such as an ultra-high pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a carbon arc, a black light lamp, and a metal halide lamp can be used.

In the case of an electron beam, irradiation with various electron beam accelerators such as a Cockloft-Walton type, a Bande graph type, a resonance transformer type, an insulating core transformer type, a linear type, a dynamitron type, a high frequency type, and the like. A device equipped with a power source can be used, 100 to 1000 keV, preferably 100
Irradiation with electrons having an energy of about 300 keV. The irradiation dose is usually preferably about 0.5 to 30 Mrad.

The coating device 10 is a device for applying the ionizing radiation-curable resin liquid 3 to the roll intaglio 1, and it is desirable to use a nozzle coating device (the method shown in FIG. 2).
In this nozzle coating apparatus, a nozzle having a predetermined dimension has a T-die-shaped rectangular or linear discharge port, and the longitudinal direction of the discharge port is set in a direction (width direction) orthogonal to the roll intaglio rotation direction. The ionizing radiation-curable resin liquid 3 is provided so as to cover a predetermined width of the entire width of the roll intaglio 1.
And a discharge device for discharging the ink onto the roll intaglio 1 in a curtain shape by pressurizing. Further, in the nozzle coating apparatus, it is preferable to provide the cavity 12 in the middle of the nozzle in order to reduce unevenness of the discharge amount and change with time. Further, as the coating apparatus 10, a coating apparatus using a suitable means such as a roll coating method or a knife coating method on the sheet substrate 4 may be employed in addition to the above.

Although not shown, after applying the ionizing radiation-curable resin liquid 3 onto the sheet substrate 4 instead of onto the roll intaglio 1, the pressing roll 5 applies the sheet base to the roll intaglio 1. The coating surface on the material 4 can be pressed. In order to faithfully reproduce minute irregularities without mixing of air bubbles, it is preferable to apply the resin liquid 3 on the roll intaglio 1 side.

The solvent drying device 11 is a device for volatilizing the solvent of the resin. As the solvent drying device 11, warm air, an infrared heater, or the like can be used. By providing the solvent drying device 11, a solvent-type resin can be used, so that the range of choice of the resin to be used is widened, and harmony of coating properties is facilitated. When the solventless ionizing radiation-curable resin liquid 3 is used, the drying device 11 is unnecessary.

Next, the operation of the manufacturing apparatus shown in FIG. 2 and the method for manufacturing the light diffusion sheet of this embodiment will be described.
First, the concave portion 2 of the roll intaglio 1 is filled with the ionizing radiation-curable resin liquid 3 by the coating device 10 (filling step 101).
The sheet substrate 4 is also brought into contact with the resin 3 filled in the roll intaglio 1 so as to be in contact with the resin 3 (contact step 102).

Here, as a method for filling the concave portion 2 of the roll intaglio 1 with the ionizing radiation-curable resin solution 3, as shown in FIG. Is applied by a predetermined amount, and when the base sheet 4 is supplied to the roll intaglio 1, the base sheet 4 is applied via the base sheet 4 by pressing the pressing roll 5 from the back side of the base material. The ionizing radiation-curable resin liquid 3 is distributed and filled in the recess 2. In this case, a solvent-type curable resin can be used, and the ionizing radiation-curable resin liquid 3 applied to the sheet substrate 4 is used in order to control fluidity to some extent.
Drying the solvent used to dilute the solvent
1, the resin liquid 3 from which the solvent has been dried is semi-cured by the curing device 7a. Curing device 7a
May be one as shown in FIG. 2A,
As shown in (B), a plurality (5 in this embodiment)
The curing devices 7a-1 to 7a-5 may be provided to cure the resin liquid 3 in the roll intaglio 1 in multiple stages. In this way, even if the running speed of the sheet substrate 4 is increased, a sufficient irradiation amount can be obtained. Also, by gradually curing, the distortion of the cured product of the resin liquid 3 and the It is preferable for reducing curling and distortion.

Next, while the sheet substrate 4 is in contact with the roll intaglio 1 (specifically, when the sheet substrate 4 is located between the pressing roll 5 and the feed roll 6 in the figure), the curing device 7a is used. The ionizing radiation-curable resin liquid 3 is cured (curing step 103).

In this embodiment, when ionizing radiation is irradiated by the curing device 7a, the irradiation is performed from the sheet substrate 4 side. And it can be irradiated from the inside of the roll intaglio 1 (specifically, by an irradiation device installed inside the roll hollow). Irradiation may be performed from both sides of the sheet substrate and the inner side of the intaglio.

The curing device 7 causes the concave portion 2 of the roll intaglio 1
The ionizing radiation-curable resin liquid 3a inside is adhered to the sheet substrate 4 (adhesion step 104). At this time, the degree of curing may be at least such that the fluidity of the resin 3 is lost and the adhesiveness with the sheet substrate 4 is generated.

After passing through the curing device 7, the sheet substrate 4 is peeled from the roll intaglio 1 (peeling step 105). As a result, the cured ionizing radiation-curable resin liquid 3a is integrated with the sheet substrate 4 and detached from the concave portion 2, thereby obtaining the light diffusion sheet 9 having an uneven surface.

Next, a light diffusion sheet manufactured by the method according to this embodiment and a liquid crystal display device using the same will be described. The liquid crystal display device may be of various known types, and may be black and white or color (including natural colors). Further, it may be a type that displays numbers and characters used for a display unit of a clock, an electronic desk calculator, various instruments, a word processor, or the like, or may be a type that displays general images such as a television, an output monitor of an electronic computer, and the like. .

FIG. 3 is a diagram showing an embodiment of a liquid crystal display device using a transmission type light diffusion sheet. Since the liquid crystal display 31 does not emit light by itself, a light source 32 is placed on the back surface to illuminate the display in order to improve the visibility of display in a dark place. As the light source 32, a fluorescent lamp, an incandescent lamp, or the like can be used.
From the viewpoint of life and the like, a white fluorescent lamp is preferably used.
The light source 32 is accommodated in the light reflection frame 33, is reflected by the reflection plate 34 on the back surface side, and illuminates the liquid crystal display 31 through the light curtain 35. At this time, the light source 3
So that the shape of 2 is not conspicuous and the screen has a uniform brightness
A light diffusion sheet 36 for diffusing the transmitted light from the light source 32 is required. The light diffusing sheet 36 is a sheet for diffusing transmitted light, as shown in FIG. 3B, in which a fine embossed layer 36b made of a cured product of an ionizing radiation curable resin is formed on a sheet base material 36a. It is.

FIG. 4 is a diagram showing an embodiment of a liquid crystal display device using a reflection type light diffusion sheet. On the back surface of the liquid crystal display 41, a transparent acrylic light guide plate 42 is provided.
The cold cathode FL lamp 44 housed in the lamp holder 43 is provided on a side surface of the light guide plate 42. A light diffusion sheet 45 is disposed on the back surface of the light guide plate 42. The light diffusion sheet 45 is a sheet for diffusing reflected light. As shown in FIG. 4B, a light reflection layer 45b made of a metal film of aluminum, chromium, silver, or the like is provided on the back surface of the sheet base 45a. A fine embossed layer 45c formed of a cured product of an ionizing radiation-curable resin on the surface
Is formed. In addition, if necessary, the substrate 45d
May be laminated. This is the same for the transmission type.

FIGS. 5 to 9 schematically show some examples of the light diffusion sheet manufactured by the manufacturing method according to the embodiment. FIGS. 10 and 11 show the optical characteristics of the light diffusion sheet. It is a figure for explaining. The light diffusion sheet diffuses and transmits or reflects light rays from a light source (a linear light source or a point light source). The important points are as follows.

First, the light diffusion sheet is cloudy (slid).
When light is diffused isotropically like glass, the light is also dispersed to the tangential method of the light diffusion sheet which is not practically necessary, and the light use efficiency is reduced. For this reason, practically, light is diffused only within an angle range observed by an observer. Specifically, this angle range includes a half-value angle θH.
The half-value angle θH is such that the transmittance (or reflectance) in the normal direction N of the display screen attenuates as the angle from the normal N increases,
The light intensity I is 1 / (1) of the transmittance (or reflectance) in the normal direction N.
It refers to the angle range that attenuates to 2 (FIG. 10).

The half-value angle θH is preferably about 10 ° ≦ θH ≦ 60 ° in both the horizontal and vertical directions, although it depends on the application. More preferably, about 40 ° ≦ θH ≦ 60 °. However, television, word processors,
Since the use of a monitor such as a computer mainly requires a horizontal visual field, the horizontal half-value angle θHH and the vertical half-value angle θHV are respectively 40 ° ≦ θHH ≦ 60 ° and 10 ° ≦ θHV ≦
When the angle is set to about 20 °, the light energy utilization efficiency is good and the screen is easy to see (FIG. 11).

Next, the light transmittance (or reflectance) and its angle dependence need to be uniform without variation depending on the location of the light diffusion sheet.

The shape is designed to satisfy the above, and examples of preferable shapes include the examples shown in FIGS. 5 to 8 show a so-called fly-eye lens or a modified example thereof. The light diffusion sheet 50 shown in FIG. 5 has a large number of hemispherical optical elements 51 arranged. The light diffusion sheet 60 shown in FIG. 6 has a large number of conical optical elements 61 having side surfaces that are concave toward the outside. The pitch Pmin is about 100 μm. The light diffusion sheet 70 shown in FIG. 7 has a large number of conical optical elements 71 arranged. Note that the apex angle θ = 90
Processing can be performed at any of °, 110 °, and 120 °.

The light diffusion sheet 80 shown in FIG. 8 has a large number of prism-shaped optical elements 81 such as isosceles triangles. Here, the vertical angle θ = 90 °, 110 °, 12
Processing is possible at any of 0 °. Also, pitch Pmi
n = about 70 μm. As shown in FIG. 8B, if a flat portion 82 of about 5 to 10 μm is provided between the optical elements 81, the processing accuracy is further improved.

The light diffusion sheet 90 shown in FIG.
Optical element 9 in the form of a Fresnel lens or its deformation
1 is arranged in a large number. The convex shape of the optical element 91 is not a concentric ring group as shown in the figure, but a concentric polygon (3, 4, 5, 6, 7, 8, octagon, etc.) convex group (not shown). You may.

In addition, as a fly-eye lens or a modification thereof, for example, a polygonal pyramid, a truncated cone, or the same shape and the same body type of a truncated polygonal pyramid are isotropically arranged on a plane. Things can be formed. Here, when a regular triangular pyramid (or truncated pyramid), a regular quadrangular pyramid (or truncated pyramid), or a regular hexagonal pyramid (or truncated pyramid) is used as the pyramid or the truncated pyramid, the pyramid or the truncated pyramid can be arranged in a plane without any gap and the shape is isotropic. It is preferable to be able to have the same half-value angle in the horizontal and vertical directions, and to have no variation depending on the place.

The fine embossed layer may be formed on either the front surface or the back surface of the sheet substrate 4, or may be provided on both the front and back surfaces. As an example of providing a light diffusion layer on both surfaces, for example, as shown in FIG. 6, a light diffusion layer composed of a regular hexagonal pyramid-shaped fine lens element 61 is provided on the front surface (liquid crystal side), and FIG.
And the like, in which a concentric light diffusion layer is provided.

As a processing method of these shapes, for example,
Using a lathe on a roll of metal or the like, or machining a prototype of metal or the like with a numerically controlled cutting machine, then quenching the prototype itself, or forming an uneven shape from the prototype by electroforming A method of processing a metal roll-shaped plate material by a well-known milling method using a mold obtained by further molding a different metal as a mill, if the cross-sectional shape in the normal direction of the plate is simple, A known photo-corrosion method can also be used.

[0043]

As described above in detail, according to the present invention, since the resin is molded into the shape of the previously designed roll intaglio, the desired fine embossed shape can be faithfully reproduced. Therefore, a material having a desired diffusion characteristic can be manufactured with high accuracy, and variation due to a position in a screen hardly occurs.

Further, since a light-diffusing fine embossed shape is formed on the surface of the transparent resin and no foreign particles are dispersed therein, a light-diffusing sheet with less light loss can be obtained.

Further, while running the sheet substrate of the belt-shaped web, a fine emboss is formed by a rotary molding method using a roll intaglio, and the molding is also immediately cured by ionizing radiation, so that mass production is possible.

[Brief description of the drawings]

FIG. 1 is a process diagram showing an embodiment of a method for producing a light diffusion sheet according to the present invention.

FIG. 2 is a view showing an embodiment of a light diffusion sheet manufacturing apparatus according to the present invention.

FIG. 3 is a diagram showing an embodiment of a liquid crystal display device using a transmission type light diffusion sheet.

FIG. 4 is a diagram showing an embodiment of a liquid crystal display device using a reflection type light diffusion sheet.

FIG. 5 is a diagram schematically illustrating an example of a light diffusion sheet manufactured by a manufacturing method according to an example.

FIG. 6 is a diagram schematically illustrating an example of a light diffusion sheet manufactured by a manufacturing method according to an example.

FIG. 7 is a diagram schematically illustrating an example of a light diffusion sheet manufactured by a manufacturing method according to an example.

FIG. 8 is a diagram schematically illustrating an example of a light diffusion sheet manufactured by a manufacturing method according to an example.

FIG. 9 is a diagram schematically illustrating an example of a light diffusion sheet manufactured by a manufacturing method according to an example.

FIG. 10 is a diagram for explaining optical characteristics of a light diffusion sheet.

FIG. 11 is a diagram for explaining optical characteristics of a light diffusion sheet.

FIG. 12 is a diagram showing another example of the roll intaglio used in the light diffusion sheet manufacturing apparatus according to the example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Roll intaglio 3 Ionizing radiation curable resin liquid 4 Sheet base material 5 Press roll 6 Feed roll 7 Curing device 10 Coating device 50-90 Light diffusion sheet 101 Filling process 102 Contact process 103 Curing process 104 Adhesion process 105 Peeling process

──────────────────────────────────────────────────続 き Continuation of front page (51) Int.Cl. ⁷ Identification symbol FI B29D 11/00 B29D 11/00 (56) References JP-A-2-131175 (JP, A) JP-A-2-118932 (JP) JP-A-54-152050 (JP, A) JP-A-3-76874 (JP, A) JP-A-1-152044 (JP, A) JP-A-2-70412 (JP, A) 1-335737 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) B29C 59/00-59/18 B05C 1/08 B05D 3/06 B05D 7/04 B29C 39/10 B29D 11 / 00

Claims (1)

(57) [Claims] 1. A half-value angle theta _H is 10 ° ≦ Θ _H ≦ 60 ° der
A roll intaglio having a light-diffusing micro-embossed mold formed thereon, and applying an ionizing radiation-curable resin liquid to at least the recesses of the roll intaglio using a coating apparatus. A filling step of filling by applying a fixed amount; and a transparent resin sheet base running in synchronization with a rotation direction of the roll intaglio with respect to the ionizing radiation-curable resin liquid filled in the roll intaglio in the filling step. A contacting step of contacting the material and simultaneously pressing the transparent resin sheet base material to the roll intaglio by a pressing roll; while the sheet base material is in contact with the roll intaglio in the contacting step, the roll intaglio and A curing step of irradiating the ionizing radiation-curable resin liquid between the sheet base materials with ionizing radiation and curing; the ionizing radiation-curable resin liquid cured in the curing step; An adhesion step of adhering the over preparative substrate; a cured product and the sheet base material of the ionizing radiation-curable resin liquid in close contact with the contact step and a peeling step of peeling from the roll intaglio; the ionizing radiation curing A method for producing a light diffusing sheet, wherein the viscosity of the conductive resin liquid is 5000 cps or less, and the surface temperature of the roll intaglio is about 15 ° C to 50 ° C.