KR20170092892A - Light diffusion sheet for lcd back light unit having excellent polarization - Google Patents
Light diffusion sheet for lcd back light unit having excellent polarization Download PDFInfo
- Publication number
- KR20170092892A KR20170092892A KR1020160014134A KR20160014134A KR20170092892A KR 20170092892 A KR20170092892 A KR 20170092892A KR 1020160014134 A KR1020160014134 A KR 1020160014134A KR 20160014134 A KR20160014134 A KR 20160014134A KR 20170092892 A KR20170092892 A KR 20170092892A
- Authority
- KR
- South Korea
- Prior art keywords
- particles
- light
- light diffusion
- layer
- lcd backlight
- Prior art date
Links
Images
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/02—Diffusing elements; Afocal elements
- G02B5/0205—Diffusing elements; Afocal elements characterised by the diffusing properties
- G02B5/021—Diffusing elements; Afocal elements characterised by the diffusing properties the diffusion taking place at the element's surface, e.g. by means of surface roughening or microprismatic structures
- G02B5/0215—Diffusing elements; Afocal elements characterised by the diffusing properties the diffusion taking place at the element's surface, e.g. by means of surface roughening or microprismatic structures the surface having a regular structure
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
- G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
- G02B6/0013—Means for improving the coupling-in of light from the light source into the light guide
- G02B6/0023—Means for improving the coupling-in of light from the light source into the light guide provided by one optical element, or plurality thereof, placed between the light guide and the light source, or around the light source
- G02B6/0025—Diffusing sheet or layer; Prismatic sheet or layer
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
- G02F1/1336—Illuminating devices
Abstract
Description
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light diffusing sheet for LCD backlight and, more particularly, to a light diffusing sheet having a single layer or a mixture of a binder resin and a monodisperse particle having a particle diameter of 2 to 7 m, The present invention relates to a light diffusion sheet for an LCD backlight, which improves the light scattering sheet and the light guide plate generated after assembling the LCD backlight.
BACKGROUND ART [0002] In a liquid crystal display device, a backlight system in which a liquid crystal layer is irradiated from the back surface to emit light is popular. In general, the backlight unit includes an EDGE-type backlight unit and a SIDE-type backlight unit in which one or more lamps are installed and a linear lamp is installed on one end surface of the light guide plate. In this case, A light diffusing sheet is used to convert light into uniform light in the front direction of the backlight unit. In addition, as a direct-type backlight unit used in a TV or a partially-enlarged monitor, even when a plurality of lamps are provided on the rear surface of a backlight, a light diffusion sheet is used to diffuse linearly visible light into uniform light in the front direction do.
At this time, the reflective film, the light guide plate, the prism film, and the like overlap each other and perform their respective functions. The intensity of light emitted from the initial light source is gradually canceled, and the brightness is decreased. In order to solve such a problem, various attempts have been made with respect to the light diffusion sheet for high brightness such as selection of particles with good diffusion efficiency and reduction of coating thickness. In particular, a light diffusion layer containing light diffusion particles in a binder resin has been developed and used in order to perform a concealing function and a diffusion function of the light diffusion sheet for an LCD backlight and to improve brightness.
As a part of this research, Korean Patent Laid-Open Publication No. 2001-054274 discloses a light diffusion film formed on one side of a substrate made of a polymeric resin film in which a light diffusion layer made of an inorganic or organic light-diffusing agent and a transparent binder resin is transparent, Discloses a light diffusion film in which particles of a light diffusion layer are formed with a thickness of 50 mu m or less and a lamination ratio of 10% or less. Korean Patent Publication No. 2005-0050526 discloses a light diffusion film having a dispersion degree (PDI) And a light diffusing layer containing a light diffusing layer.
However, the binder used in the adhesive-resistant layer and the like is weak in abrasion resistance and easily scratched. When particles are dispersed in the binder, when the light diffusion sheet is overlapped in manufacturing, transporting and storing the light diffusion sheet, There arises a problem that after assembling to the backlight unit, the light guide plate abuts against the light guide plate under the light diffusion sheet, and the light guide plate is broken. Therefore, there is a need to develop a light diffusion sheet which does not cause a break with the light guide plate without changing the role and structure of the light diffusion sheet in the LCD backlight.
An object of the present invention is to provide a light-diffusing sheet for an LCD backlight which is produced by applying a light diffusion layer comprising a binder resin and a mixed liquid in which two kinds of monodisperse particles having a particle size of 2 to 7 mu m are used, on one side or both sides of a transparent polyester film base .
More specifically, in order to improve the separation between the light diffusion sheet and the light guide plate, the light diffusion layer is formed of a single layer between the binder resins, and the thickness thereof is 5 to 8 탆. Thereby providing a diffusion sheet.
The light diffusing sheet for LCD backlight for achieving the object of the present invention comprises a transparent polyester film base and a light diffusion layer formed on one side or both sides of the film and the light diffusion layer comprises a binder resin and particles having different particle diameters , And the particles are prepared by mixing two kinds of monodisperse particles having a particle diameter of 2 to 7 mu m.
And the light diffusion layer is formed such that the particles are formed as a single layer between the binder resins.
The light diffusion layer is formed using the refractive index of the particles of 1.05 to 2.00, and the binder resin has a refractive index of 1.2 to 1.4.
The particles are two or more selected from the group consisting of acrylic, urethane, silicone, and polyester.
The shattering improving light diffusion sheet for LCD backlight of the present invention has a haze of 50 to 90% and a transmittance of 60 to 90%, and the thickness of the light diffusion layer is 5 to 8 탆.
The light diffusing sheet for an LCD backlight according to the present invention has a single layer of particles having different particle diameters on the surface of a base film so that the thickness of the coating layer is 5 to 8 占 퐉 as compared with a conventional light diffusion sheet, It satisfies the haze of 50 to 90% and the transmittance of 60 to 90% by the arrangement, and provides a frictional improvement effect in friction with the light guide plate.
More specifically, the light diffusion sheet of the present invention has a monolayer coating to control the thickness increase, and uniform diffusion of light through arrangement of the monodisperse particles, thereby suppressing the decrease in brightness and shielding.
The light diffusing sheet for an LCD backlight of the present invention has the same physical properties and appearance as the conventional light diffusing sheet and has a function of preventing the light guide plate from being shrunk to improve the defective rate by 50% .
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic cross-sectional view of a shattering light diffusion sheet applied to an LCD backlight according to a preferred embodiment of the present invention. FIG.
Hereinafter, the present invention will be described in more detail.
1, the light diffusion sheet of the present invention comprises a
Any transparent substrate may be used for the base film, and a transparent polycarbonate film or a polyethylene terephthalate film having a transmittance of 90% or more can be used. Such a base film has adhesion to the binder resin of the light diffusion layer, and the light transmittance of the base material itself is high, so that it does not affect the light diffusion layer, and the smoothness of the surface is uniform.
The binder resin used in the light-diffusing layer should be transparent and may be used alone or in a mixture of two or more of resins such as acrylic, urethane, epoxy, polyester, and polyamide resins. The resin preferably has a refractive index of 1.2 to 1.4.
The particles of the light-diffusing layer are composed of monodisperse particles having an average particle diameter in the range of 2 to 7 mu m, and two or more kinds of particles can be used in combination. The average particle size is the size of particles occupying 90% or more of the particles used in the light diffusion layer.
If the maximum particle size of the average particle diameter is more than 7 mu m, the coating thickness and the light diffusion property of the particle are not suitably affected. If the maximum particle size of the average particle diameter is less than 3 mu m, the single layer coating of the particles becomes difficult. Further, when the minimum particle size of the average particle size is smaller than 2 탆, dispersion of large particles and small particles becomes difficult.
In order to obtain a light diffusing sheet excellent in shatter prevention, it is preferable to coat the particles with a single layer and coat such that small particles (particles having high hardness) are filled well between large particles (particles having low hardness). If particles having a minimum particle size of less than 1 占 퐉 are used, the particles are aggregated with each other, which makes dispersion difficult, and when particles smaller than 1 占 퐉 rise up to the upper layer, the scattering and luminance are lowered.
The particles of the light diffusion layer are preferably transparent spherical particles, and particles of acrylic, urethane, silicone, polyethylene terephthalate or the like can be used in combination of two or more kinds. The refractive index of the particles forming the light-diffusing layer is preferably 1.05 to 2.00, and particles having a refractive index other than the above range are not preferable because of difficulty in the manufacturing process.
The light diffusion sheet of the present invention is formed so that a coating layer is formed on the surface of a base film with a resin and a particle but a single layer coating is performed to control the thickness increase and to spread the light uniformly to improve brightness and to be shielded .
Preferably, in order to realize a light diffusion sheet satisfying brightness and lamp shielding, it is preferable that the composition ratio of the resin and the particle in one surface of the coating layer is 1: 0.5 to 1.5 in weight ratio. Excessively larger or smaller number of particles outside the above-mentioned ratio may cause unevenness of the surface, resulting in problems in luminance and shielding force.
Preferably, the light-diffusing sheet for LCD backlight has a haze of 50 to 90% and a transmittance of 60 to 90%, and the thickness of the light-diffusing layer is preferably 5 to 8 탆.
The back surface of the light diffusing layer formed on one surface with such a light diffusion sheet is provided with antistatic properties to prevent foreign matter that can be generated during sheet production, cutting and assembly and to provide a slip property to suppress shattering and warping A coating layer can be formed.
The light diffusion sheet for an LCD backlight manufactured according to the present invention has a defect ratio of 50% or more as compared with a conventional general light diffusion sheet when mounted on a backlight unit.
Hereinafter, the present invention will be described in more detail with reference to Examples. These examples are intended to further illustrate the present invention, and the scope of the present invention is not limited to these examples.
The particles (refractive index: 1.49) and the binder resin (refractive index: 1.35) used in the following examples and comparative examples were all the same kinds. The samples were prepared and evaluated according to the particle size and the content of each particle.
< Example 1 >
On one side of a transparent polyester film (Toray, U46 100 占 퐉), a coating layer having a composition 1 shown below was formed using a microgravure roll and a coating layer having a composition 2 on the other side was coated with microgravure A roll was used to form a coating layer.
Composition of coating liquid 1
- Acrylic resin (Aekyung Chemical Co., Ltd., A-814): 30.0 wt%
- Acrylic hardener (Aekyung Chemical Co., Ltd., DN-950): 3.0 wt%
- Acrylic particles (SOKEN, MX500, average particle diameter 5 탆): 20.0 wt%
- Acrylic particles (SOKEN, MX300, average particle diameter 3 mu m): 5.0 wt%
Solvent (methyl ethyl ketone): 42.0 wt%
Composition of coating liquid 2
-Acrylic resin (Aekyung Chemical Co., Ltd., A-184): 34.8 wt%
- Acrylic hardener (Aekyung Chemical Co., Ltd., DN-950): 3.2 wt%
- Acrylic particles (SOKEN, MR7HG, average particle size 6 mu m): 0.6 wt%
- PMMA particles (KOLON, MH-5FD, average particle diameter 5 탆): 0.4 wt%
- Solvent (methyl ethyl ketone): 60.0 wt%
- Additive (KAO, KS-1248): 1.0 wt%
< Example 2>
On one side of a transparent polyester film (Toray, U46 100 占 퐉), a coating layer having a composition 1 shown below was formed using a microgravure roll and a coating layer having a composition 2 on the other side was coated with microgravure A coated layer is formed using a roll.
Composition of coating liquid 1
- Acrylic resin (Aekyung Chemical Co., Ltd., A-814) : 30.0 wt%
- Acrylic hardener (Aekyung Chemical Co., Ltd., DN-950): 3.0 wt%
- Acrylic particles (SOKEN, MX500, average particle diameter 5 탆): 20.0 wt%
- Acrylic particles (SOKEN, MX300, average particle diameter 3 mu m): 5.0 wt%
Solvent (methyl ethyl ketone): 42.0 wt%
Composition of coating liquid 2
- urethane resin (Aekyung Chemical Co., Ltd., AA-921): 34.8 wt%
- Acrylic hardener (Aekyung Chemical Co., Ltd., DN-950): 3.2 wt%
- Acrylic particles (SOKEN, MR7HG, average particle diameter 6 mu m): 1.0 wt%
- Solvent (methyl ethyl ketone): 60.0 wt%
- Additive (KAO, KS-1248): 1.0 wt%
< Example 3>
On one side of a transparent polyester film (Toray, U46 100 m), a coating liquid having the following composition 1 was formed by using a microgravure roll, and a coating liquid having a composition 2 on the other side was coated with microgravure A coated layer is formed using a roll.
Composition of coating liquid 1
- Acrylic resin (Aekyung Chemical Co., Ltd., A-814): 30.0 wt%
- Acrylic hardener (Aekyung Chemical Co., Ltd., DN-950): 3.0 wt%
- Acrylic particles (SOKEN, MX500, average particle diameter 5 탆): 20.0 wt%
- Acrylic particles (SOKEN, MX300, average particle diameter 3 mu m): 5.0 wt%
Solvent (methyl ethyl ketone): 42.0 wt%
Composition of coating liquid 2
- urethane resin (Aekyung Chemical Co., Ltd., AA-921): 34.8 wt%
- Acrylic hardener (Aekyung Chemical Co., Ltd., DN-950): 3.2 wt%
- Acrylic particles (SOKEN, MR7HG, average particle size 6 mu m): 0.6 wt%
- PMMA particles (KOLON, MH-5FD, average particle diameter 5 탆): 0.4 wt%
- Solvent (methyl ethyl ketone): 60.0 wt%
- Additive (KAO, KS-1248): 1.0 wt%
< Comparative Example 1>
On one side of a transparent polyester film (Toray, U46 100 m) as in Example 1, a coating layer was formed using a microgravure roll with a coating solution having the following composition, and a coating layer having a composition 2 on the other side A coating layer is formed by using a microgravure roll as a solution.
Composition of coating liquid 1
- Acrylic resin (Aekyung Chemical Co., Ltd., A-814): 30.0 wt%
- Acrylic hardener (Aekyung Chemical Co., Ltd., DN-950): 3.0 wt%
- Acrylic particles (SOKEN, MX500, average particle diameter 5 탆): 20.0 wt%
- Acrylic particles (SOKEN, MX300, average particle diameter 3 mu m): 5.0 wt%
Solvent (methyl ethyl ketone): 42.0 wt%
Composition of coating liquid 2
-Acrylic resin (Aekyung Chemical Co., Ltd., A-184): 34.8 wt%
- Acrylic hardener (Aekyung Chemical Co., Ltd., DN-950): 3.2 wt%
- Acrylic particles (SOKEN, MR7HG, average particle size 6 mu m): 0.6 wt%
- Acrylic particles (SOKEN, MX1000,
- Solvent (methyl ethyl ketone): 60.0 wt%
- Additive (KAO, KS-1248): 1.0 wt%
< Comparative Example 2>
The coating solution 2 was prepared in the same manner as in Comparative Example 1, except that MX1500 (SOKEN, average particle size of 15 mu m) was used instead of MX1000.
< Comparative Example 3>
The coating liquid 2 was prepared in the same manner as in Comparative Example 1, except that DX100 (KOLON, PMMA particles, average particle size of 9 mu m) was used instead of MX1000.
< Comparative Example 4>
The coating solution 2 was prepared in the same manner as in Comparative Example 1, except that HItech 10 (Advanced Chemistry, PBMA particles, average particle diameter 7 μm) was used instead of MX1000.
< Comparative Example 5>
Coating solution 2 was prepared in the same manner as in Example 2 except that acrylic A-814 (Aekyung Chemical) was used instead of urethane resin AA-921.
< Comparative Example 6>
The coating liquid 2 was prepared in the same manner as in Example 2 except that DRTR-02 (Samhwa paint, thermoset acrylic resin) was used instead of resin AA-921.
< Comparative Example 7>
The coating liquid 2 was prepared in the same manner as in Example 2 except that SH-320 (Samhwa paint, UV cured acrylic resin) was used instead of resin AA-921.
< Experimental Example >
The properties of the sheets prepared in Examples 1 to 3 and Comparative Examples 1 to 7 were measured as described below and shown in Table 1.
1. Measurement of thickness of coating layer
The thickness of the coated layer of the sheets prepared in Examples 1 to 3 and Comparative Examples 1 to 7 was determined using a side pressure measuring instrument (Mitsutoyo Corporation, Model: ID-FF125) using a micrometer.
2. Haze & Transmittance Measurement
The haze and transmittance of the sheets prepared in Examples 1 to 3 and Comparative Examples 1 to 7 were measured with a haze meter (NIPPON DENSHOKU KOGYO Co. Ltd. Model 1000) manufactured by NIPPON DENKO CO., LTD based on ASTM D-1003 .
3. Measurement of luminance
For the sheets prepared in Examples 1 to 3 and Comparative Examples 1 to 7, two sheets of prism sheets (3M yarns) were put on a manufactured sheet using BM-7 equipment, and the vertical luminance on the backlight unit assembly was measured .
4. Adhesion measurement
The sheets prepared in Examples 1 to 3 and Comparative Examples 1 to 7 were cut into a coating layer using a cross cutter (NITTO DENDKO) to prepare 100 square cells each having a size of 60 mu m x 60 mu m and then using 3M magic tape And the degree of peeling was measured.
O: One square cell is not dropped
X: One square cell is missing
5. Confirm shielding force
The sheets prepared in Examples 1 to 3 and Comparative Examples 1 to 7 were assembled in a backlight unit (V12 32 ", development model) using an LED lamp to confirm whether or not hot spot was observed.
Excellent: If hot spot is not visible
Good: If hot spot poet is weak
Bad: Hot Spot Poet
6. Confirmation of shoring evaluation
With respect to the sheets produced in Examples 1 to 3 and Comparative Examples 1 to 7, the presence or absence of sheet shattering is checked by using a shredding repeat evaluating device (HEIDON-14FW).
Blast rate = number of blasted samples (sheets) / number of blasted samples (sheets) * 100
As shown in Table 1, according to Examples 1 to 2, when two kinds of particles having different materials and sizes are applied in a single dispersion size, there is a tendency to be excellent in the evaluation of the shattering. Also, , It can be seen that the evaluation is excellent. It can be seen from Table 3 that when the two kinds of particles having different materials and the similar size and the resin having good elasticity are applied in Example 3, the occurrence of the cracking is the smallest at 8%.
Also, according to Comparative Example 2 and Comparative Example 4, when two monodisperse particles having different sizes but different sizes are applied, the occurrence rate of blasting is increased. According to Comparative Examples 5 to 7, a resin having a low elasticity is applied The incidence of blasting is high.
(10) Base film
(11) Binder resin
(12) ------------ particles
Claims (7)
Wherein the light diffusion layer comprises a binder resin and a mixture of particles having different particle diameters,
Wherein the particles are at least two monodisperse particles having an average particle diameter of 2 to 7 占 퐉.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1020160014134A KR20170092892A (en) | 2016-02-04 | 2016-02-04 | Light diffusion sheet for lcd back light unit having excellent polarization |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1020160014134A KR20170092892A (en) | 2016-02-04 | 2016-02-04 | Light diffusion sheet for lcd back light unit having excellent polarization |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| KR20170092892A true KR20170092892A (en) | 2017-08-14 |
Family
ID=60142018
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| KR1020160014134A KR20170092892A (en) | 2016-02-04 | 2016-02-04 | Light diffusion sheet for lcd back light unit having excellent polarization |
Country Status (1)
| Country | Link |
|---|---|
| KR (1) | KR20170092892A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20210034914A (en) * | 2019-09-23 | 2021-03-31 | 주식회사 엘엠에스 | Optical film for fingerprinting |
-
2016
- 2016-02-04 KR KR1020160014134A patent/KR20170092892A/en unknown
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20210034914A (en) * | 2019-09-23 | 2021-03-31 | 주식회사 엘엠에스 | Optical film for fingerprinting |
| WO2021060708A1 (en) * | 2019-09-23 | 2021-04-01 | 주식회사 엘엠에스 | Optical film for fingerprint recognition |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| KR101608127B1 (en) | Optical diffusion film and liquid crystal display backlight source using the same | |
| KR101920523B1 (en) | Anti-glare film, polarizing plate and image display device | |
| KR100680127B1 (en) | Light-diffusing sheet for back light unit of liquid crystal display | |
| JP2007206674A (en) | Optical thin sheet | |
| US20080213513A1 (en) | Antiglare film | |
| KR20090056903A (en) | Multi-functional optic sheet | |
| KR102105135B1 (en) | A buffer sheet and a flat panel display | |
| KR100909427B1 (en) | Light control film | |
| KR100920645B1 (en) | Prism Complex Film | |
| KR101752245B1 (en) | Light Diffusing Sheet for Back Light Unit | |
| TW200304552A (en) | Anti-Newton ring sheet | |
| KR101087026B1 (en) | Multi-functional optic film | |
| KR20120078508A (en) | Optical sheet | |
| KR20170092892A (en) | Light diffusion sheet for lcd back light unit having excellent polarization | |
| KR20130053489A (en) | Light diffusion sheet for a back light unit and the manufacturing method thereof | |
| WO2021235491A1 (en) | Optical sheet, backlight unit, liquid crystal display apparatus, and information device | |
| KR100988764B1 (en) | Multi-functional optic film | |
| JP2006058616A (en) | Glare-proof film, glare-proof polarizing plate, image display device and selection method of glare-proof film | |
| KR100920371B1 (en) | Light-diffusing film for direct back light unit of lcd | |
| KR20110076320A (en) | Prism film having complex function and preparing thereof | |
| KR100973599B1 (en) | Optical film eliminating protective films and Preparing thereof | |
| KR100804061B1 (en) | Diffuser film for high luminance LCD backlight | |
| KR20180074288A (en) | Light Diffusing Sheet for Back-light Unit | |
| KR20090129655A (en) | Light-diffusing sheet and diffusing sheet for back light unit | |
| KR20110133678A (en) | Light-diffusing sheet for lcd back light unit |