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KR20090030455A - Brightness enhancement sheet of lcd backlight unit - Google Patents

Brightness enhancement sheet of lcd backlight unit Download PDF

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Publication number
KR20090030455A
KR20090030455A KR1020070095774A KR20070095774A KR20090030455A KR 20090030455 A KR20090030455 A KR 20090030455A KR 1020070095774 A KR1020070095774 A KR 1020070095774A KR 20070095774 A KR20070095774 A KR 20070095774A KR 20090030455 A KR20090030455 A KR 20090030455A
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KR
South Korea
Prior art keywords
sheet
light
prism
brightness
present
Prior art date
Application number
KR1020070095774A
Other languages
Korean (ko)
Inventor
홍병희
Original Assignee
홍병희
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 홍병희 filed Critical 홍병희
Priority to KR1020070095774A priority Critical patent/KR20090030455A/en
Publication of KR20090030455A publication Critical patent/KR20090030455A/en

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    • 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
    • G02B6/0033—Means for improving the coupling-out of light from the light guide
    • G02B6/0035—Means for improving the coupling-out of light from the light guide provided on the surface of the light guide or in the bulk of it
    • G02B6/0036—2-D arrangement of prisms, protrusions, indentations or roughened surfaces
    • 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
    • G02B6/0033—Means for improving the coupling-out of light from the light guide
    • G02B6/005—Means for improving the coupling-out of light from the light guide provided by one optical element, or plurality thereof, placed on the light output side of the light guide
    • G02B6/0053—Prismatic sheet or layer; Brightness enhancement element, sheet or layer
    • 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
    • G02B6/0033—Means for improving the coupling-out of light from the light guide
    • G02B6/0058—Means for improving the coupling-out of light from the light guide varying in density, size, shape or depth along the light guide
    • G02B6/0061—Means for improving the coupling-out of light from the light guide varying in density, size, shape or depth along the light guide to provide homogeneous light output intensity
    • 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
    • G02F1/133504—Diffusing, scattering, diffracting elements
    • 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
    • G02F1/133602—Direct backlight
    • G02F1/133606—Direct backlight including a specially adapted diffusing, scattering or light controlling members

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Nonlinear Science (AREA)
  • Mathematical Physics (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Optical Elements Other Than Lenses (AREA)

Abstract

The present invention relates to a brightness improving sheet of an LCD backlight unit, and to provide an optical sheet having better brightness improving characteristics than conventional optical sheets. The brightness enhancing sheet of the present invention includes a substrate having an upper surface and made of a transparent material, and a plurality of prism structures formed on the upper surface of the substrate and made of a transparent material. In particular, the prism structures extend in a first direction and are formed in a discontinuous pattern along a second direction perpendicular to the first direction, exposing the upper surface of the substrate between the prism structures. The brightness enhancing sheet of the present invention can be particularly optimized for a direct type backlight unit.

Description

Brightness improvement sheet of LCD backlight unit {BRIGHTNESS ENHANCEMENT SHEET OF LCD BACKLIGHT UNIT}

The present invention relates to a brightness improving sheet of an LCD backlight unit, and more particularly, to a brightness improving sheet for advancing a light direction perpendicular to a liquid crystal panel in order to increase the front brightness of an LCD screen.

In general, flat displays are classified into light-emitting and light-receiving types. A well-known liquid crystal display (hereinafter referred to as "LCD") is a representative example of a light receiving flat panel display. Since the LCD is difficult to emit light, the LCD forms an image through the liquid crystal unit by using light incident from a separate light source. That is, the LCD must essentially include a backlight unit installed on the back of the liquid crystal unit to irradiate light.

The backlight unit should not only stay on irradiating light but should have a characteristic of emitting light evenly across the surface in order to maintain brightness uniformity of the screen. In addition, the backlight unit should have characteristics that emit light in a direction perpendicular to the surface in order to improve the front brightness, and reflect back all the light emitted outside the upper surface so that there is no light loss. As such, the backlight unit is composed of various optical components in addition to the light source lamp, and thus, determines the price and performance of the LCD.

The backlight unit is generally classified into a side light type and a directly arrayed type according to the arrangement of the light sources. In the light guide plate type, lamps used as light sources are arranged at both edges of the light guide plate, and in the direct type, a plurality of light source lamps are evenly arranged below the diffuser plate.

The light guide plate type and the direct type have some differences in detailed configurations but commonly require a brightness enhancement sheet. The brightness improving sheet refracts and condenses the light from the diffuser sheet, the light guide plate, or the diffuser plate directly below, thereby advancing the light in a direction perpendicular to the panel of the liquid crystal unit and increasing the front luminance of the screen. The most commonly used prism sheet to perform this role is a prism sheet. In general, the prism sheet has a structure in which a prism pattern having a cross-sectional shape is continuously formed on its upper surface.

1 is a perspective view of a prism sheet according to one example of the prior art. As shown in FIG. 1, the prism sheet 10 is composed of a substrate 12 in the form of a sheet or film, and a plurality of prism structures 14 formed on an upper surface thereof. Each prism structure 14 is in the form of a triangular prism extending in one direction while being cross-shaped and mountain-shaped, and these prismatic structures 14 are continuously arranged at a constant pitch P. That is, in the conventional prism sheet 10, the prism structure 14 has a continuous pattern.

2 is a schematic diagram for explaining the optical principle of the prism sheet 10 according to the prior art. Referring to FIG. 2, light incident on the prism sheet 10 is totally reflected 21 in the prism structure 14, transmitted through refraction 22, 23, or refracted and totally reflected 24 again. Most of the light that is refracted and transmitted is emitted in the form of vertical light (22), but there is also a considerable amount of light leaking out to the side (23).

In view of the purpose of improving the luminance of the prism sheet 10, the more light emitted as vertical light among the total incident light, the more excellent the optical sheet can be. On the other hand, since all of the vertically incident light is totally reflected, the less the vertically incident light, the better the brightness enhancement effect can be expected.

Of course, the vertically incident, totally reflected or refracted totally reflected light can be used again because it is reflected from the optical sheets below the prism sheet and re-incident into the prism sheet. However, the loss of light in the process is inevitable, and even if the light is reincident to the prism sheet through the circulation process, the fundamental problem is not solved. Eventually, in order to achieve an excellent brightness enhancement effect, the amount of light emitted should be increased, and in particular, the amount of light emitted as vertical light should be increased.

On the other hand, when examining the distribution of light incident on the prism sheet, the light guide plate type has more light incident obliquely than the light incident vertically, and the direct type has more light incident vertically than the light incident obliquely. Therefore, the conventional prism sheet 10 may be said to be optimized for a light guide plate type backlight unit rather than a direct type. In the case of the direct type, since a lot of light is incident vertically and all of them are totally reflected, not only the amount of light emitted is insufficient but also the amount of vertical light is reduced.

Accordingly, an object of the present invention is to provide an optical sheet having better brightness enhancement characteristics than conventional optical sheets, and is particularly optimized for a direct type backlight unit to provide an excellent effect as well as providing a brightness enhancement sheet useful for a light guide plate type backlight unit. It is to.

Furthermore, another object of the present invention is to obtain excellent LCD screen characteristics by improving surface luminance distribution characteristics, vertical light distribution characteristics, viewing angle characteristics, and the like.

To this end, the present invention proposes a brightness enhancement sheet in which a prism structure is formed in a new pattern. Specifically, the present invention provides a brightness improving sheet of an LCD backlight unit in which the prism structures are not arranged continuously but are spaced apart at regular intervals, that is, formed in a discontinuous pattern.

The brightness improving sheet of the LCD backlight unit according to the present invention includes a substrate having an upper surface and made of a transparent material, and a plurality of prism structures formed on the upper surface of the substrate and made of a transparent material. In particular, the prism structures extend in a first direction and are formed in a discontinuous pattern along a second direction perpendicular to the first direction, exposing the upper surface of the substrate between the prism structures.

In the brightness improving sheet of the LCD backlight unit, the pitch between the prism structures and the spacing between the prism structures may be all constant, all of them may be constant, or one may be constant and the other may not be constant.

In addition, the cross section of the prism structures may be any one of a triangular, trapezoidal, and semicircular.

In addition, the size, height, and angle of the prism structures may be always constant or at least one may not be constant.

The luminance improving sheet of the LCD backlight unit according to the present invention can improve the surface luminance distribution characteristics, vertical light distribution characteristics, viewing angle characteristics, etc. by directly emitting light incident through a flat surface existing between the prism structures, and furthermore, LCD It is possible to improve the screen characteristics.

In particular, the brightness enhancing sheet according to the present invention is optimized for the direct type backlight unit to exhibit an excellent effect, and can be usefully applied to the light guide plate type backlight unit.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

However, in describing the embodiments, descriptions of technical contents that are well known in the technical field to which the present invention pertains and are not directly related to the present invention are omitted. This is to more clearly communicate without obscure the core of the present invention by omitting unnecessary description.

On the other hand, in the accompanying drawings, some components are exaggerated, omitted, or schematically illustrated, and the size of each component does not entirely reflect the actual size. Like reference numerals refer to like or corresponding elements throughout the accompanying drawings.

3 is a perspective view of a brightness improving sheet according to an embodiment of the present invention. Referring to FIG. 3, the brightness enhancing sheet 30 of the present invention is largely composed of a substrate 32 and a prism structure 34.

The substrate 32 is a sheet or film having a thickness of several tens of micrometers to several hundred micrometers. The material of the substrate 32 is a resin of a transparent material. For example, an acryl resin, polyethylene terephthalate (PET) resin, polycarbonate (PC) resin, or the like is used.

The prism structure 34 is in the form of a triangular column lying sideways, a plurality of discontinuously formed on the upper surface (32a) of the substrate (32). The material of the prism structure 34 is a resin of a transparent material similar to the material of the substrate 32. The substrate 32 and the prism structure 34 may be made of different resin materials or may be made of the same resin material.

More specifically with respect to the prism structure 34, each prism structure 34 extends along the first direction (y direction in the figure), the cross section of which is triangular. That is, the upper surface 32a of the substrate 32 and the two inclined surfaces 34a and 34b of the prism structure 34 are triangular. At this time, the prism angle θ formed by the two inclined surfaces 34a and 34b of the prism structure 34 is 90 degrees or around 90 degrees.

On the other hand, the prism structures 34 are repeated at a constant pitch P along a second direction (x direction in the drawing) perpendicular to the first direction. In particular, the prism structure 34 is spaced apart by a predetermined distance G in the second direction. That is, the neighboring prism structures 34 are spaced apart from each other by a constant gap G, between which the flat upper surface 32a of the substrate 32 is exposed. Therefore, in the brightness improving sheet 30 of the present invention, the prism structure 34 has a discontinuous pattern. The pitch P of the prism structure 34 is several tens of micrometers to several hundred micrometers, and the space | interval G is one of the moisture of the pitch P.

The prism structure of the brightness enhancing sheet according to the present invention is not necessarily limited to the above-described embodiment, and various modifications may be made as necessary as long as the prism structure has a discontinuous pattern. For example, the cross section of the prism structure may be trapezoidal, semicircular, etc. in addition to the triangle. In addition, the pitch and spacing of the prism structures are not necessarily constant, and neither the pitch nor the spacing may be constant, or either of the pitch and the spacing may not be constant. In addition, the size, height and angle of neighboring prism structures do not always have to be constant, and even in one prism structure, the height does not always have to be uniform.

4 is a schematic view for explaining the optical principle of the brightness improving sheet according to the present invention. Referring to FIG. 4, light incident toward the prism structure 34 of the brightness enhancement sheet 30 is totally reflected (not shown), transmitted through the vertical light while being refracted (42), or transmitted at an angle while being refracted (44). Refracted and totally reflected again (45). This is the same as before.

However, in the brightness improving sheet 30 of the present invention, since the prism structure 34 has a discontinuous pattern, that is, the flat surface 32a exists between the adjacent prism structures 34, the light incident through this portion is The progress path is different from the conventional one. Specifically, the incident light is directly emitted (41, 43) in the portion without the prism structure 34 and only the flat surface 32a. In particular, as indicated by the reference numeral 41, the vertically incident light shows a great difference from the conventional point in that the vertical light is output as it is.

Referring to FIG. 2 and FIG. 4, the light incident vertically is totally reflected in the prism structure 14 as indicated by 21 in FIG. 2, which is the case even in the present invention. The same applies to the part with (34). However, in the present invention, the light incident perpendicularly to the portion without the prism structure 34 is emitted as the vertical light as indicated by 41 in FIG. 4. Therefore, in the present invention, the amount of light emitted as vertical light increases.

On the other hand, in the case of obliquely incident light, conventionally, as indicated by No. 22 of FIG. 2, it is emitted as a vertical light or leaks laterally as indicated by No. 23. In the present invention, as indicated by No. 43 of FIG. 4. As it is, it is obliquely emitted. That is, when limited to only the light incident at an angle, it can be said that the light emitted as the vertical light in the portion without the prism structure 34 is somewhat reduced. But instead, the light leaking out sideways is emitted closer to the vertical light, which is more helpful for improving the brightness.

In addition, considering the overall light including vertically incident light, the effect of contributing to the increase in vertical light is that the vertically incident light is not totally reflected and is emitted as it is. This is much greater than affecting vertical light reduction. In addition, it can be seen that the effect of the discontinuous prism pattern of the present invention is superior even in terms of overall luminance rather than vertical light.

In order to confirm the above description, the inventors conducted simulations on the conventional prism sheet and the brightness enhancement sheet of the present invention, respectively, and the results are shown in FIGS. 5A and 5B. 5A and 5B are simulation graphs showing luminance characteristics according to incident angles. FIG. 5A shows vertical light average luminance and FIG. 5B shows surface average luminance, respectively. 5A and 5B, the incident angle of the x-axis (horizontal axis) is an angle formed between the upper surface of the substrate of the sheet and the incident light. For example, 90 degrees means light incident vertically.

The sheet and the surface light source used in this simulation are both 5 mm in width and width and 0.006 mm in distance between the two. In the simulation, the vertical light distribution and the surface luminance distribution of the light passing through the sheet were measured while changing the angle of the light source so that the incident angle of the light incident on the sheet was 0 degrees to 90 degrees.

Referring to FIG. 5A, it can be seen that the average brightness of the vertical light of the present invention is slightly decreased when the incident angle is 55 degrees to 65 degrees, but much higher when the incident angle is 85 degrees or more. This is because, as described above, the amount of light that is incident obliquely and is emitted as vertical light is somewhat reduced, and the amount of light that is incident vertically and is emitted as vertical light is analyzed to be much increased.

Referring to Figure 5b, it can be seen that the surface average brightness of the present invention is significantly increased compared to the prior art at the incident angle of 45 degrees or more. As described above, it is analyzed that not only the amount of light vertically incident and emitted as it is, but also the amount of light emitted as it enters obliquely and close to the vertical light increases.

Summarizing the above, it can be inferred that the brightness improving sheet according to the present invention can be optimized and used for a direct type with more light incident vertically than light incident at an angle.

On the other hand, various types are known as the brightness enhancement sheet previously developed or proposed as shown in FIG. The inventors conducted simulations to compare various characteristics of these conventional brightness enhancing sheets and the brightness enhancing sheet of the present invention.

7 is a schematic of the model used for this simulation. Referring to FIG. 7, the simulation used the brightness enhancement sheet 70, the diffusion plate 72, and the surface light source 74, all of which were the same in size of 8 mm in width (L) and 4 mm in length (W). Do. The distance t1 between the brightness enhancement sheet 70 and the diffuser plate 72 is 0.004 mm, and the distance t2 between the diffuser plate 72 and the surface light source 74 is 0.04 mm. The diffusion plate 72 has a refractive index of 1.49, a bead radius of 1000 nm, a bead refractive index of 2.00, and a number density of beads of 340,000 pieces / mm 2. The shapes of the various brightness enhancing sheets 70 used in the simulations are shown in FIG. 6, and the prism angles, prism thicknesses, total thicknesses, and refractive indices are shown in Table 1.

division Prism Angle (degrees) Prism Pitch (μm) Overall thickness (μm) Refractive index Board prism Conventional type 1 90 24 150 1.667 1.59 Conventional type 2 rounded 24 150 1.667 1.59 Conventional type 3 rounded 50 180 1.667 1.59 Conventional Type 4 flat 24 148 1.667 1.59 Conventional type 5 rounded 24 162 1.667 1.59 Conventional type 6 rounded 24 162 1.667 1.59 The present invention 90 48 148 1.667 1.59

This simulation investigated the various characteristics of the light incident on the sheet through the diffuser plate and spread through the sheet, that is, the distribution and brightness of surface brightness, the distribution and intensity of vertical light, and the viewing angle. 8A to 8C show surface luminance characteristics, FIGS. 9A to 9C show vertical light characteristics, and FIG. 10 shows viewing angle characteristics.

More specifically, FIG. 8A is a comparison of surface luminance distribution, that is, uniformity. FIGS. 8B and 8C are brightnesses of the front average surface brightness of each sheet, and FIG. 8C is used to compare the brightness of the surface brightness. The brightness of the central (1/4 area) average surface luminance of each sheet is shown.

Referring to FIG. 8A, it can be visually confirmed that the luminance improving sheet of the present invention has better surface luminance distribution than the conventional sheet. 8B and 8C, it can be seen that the surface luminance brightness of the present invention is higher than that of the conventional sheet. For example, the sheet of the present invention has increased the brightness of the surface brightness by approximately 40% compared to the conventional type 1 sheet.

9A is a comparison of the vertical light distribution, and FIGS. 9B and 9C are comparisons of the intensities of the vertical lights. FIG. 9B is the intensity of the front average vertical light of each sheet, and FIG. The intensity of the vertical light is shown respectively.

9A, it can be visually confirmed that the luminance improving sheet of the present invention has better vertical light distribution than the conventional sheet. 9B and 9C, it can be seen that the vertical light intensity of the present invention is higher than that of the conventional sheet. For example, compared to the conventional type 1 sheet, the sheet of the present invention has increased the intensity of the front average vertical light by approximately 5% and the intensity of the central average vertical light by 3%.

10 is a comparison of the viewing angle distribution, it can be seen that the viewing angle is improved in the brightness enhancement sheet of the present invention than the conventional sheet.

The brightness enhancing sheet of the present invention described above can not only replace the existing prism sheet, but can also be applied to a composite sheet in which several existing optical sheets are implemented in one sheet. In addition, the brightness improving sheet of the present invention may use only one sheet or two sheets overlapping. When using two sheets of brightness improving sheet, the upper and lower brightness enhancing sheets are overlapped so that the prism structures are perpendicular to each other.

So far, the brightness improving sheet of the LCD backlight unit according to the present invention has been described through the examples. In the present specification and drawings, preferred embodiments of the present invention have been disclosed, and although specific terms have been used, these are merely used in a general sense to easily explain the technical contents of the present invention and to help the understanding of the present invention. It is not intended to limit the scope. It will be apparent to those skilled in the art that other modifications based on the technical idea of the present invention can be carried out in addition to the embodiments disclosed herein.

1 is a perspective view of a prism sheet according to one example of the prior art.

2 is a schematic view for explaining the optical principle of the prism sheet according to the prior art.

3 is a perspective view of a brightness improving sheet according to an embodiment of the present invention.

4 is a schematic view for explaining the optical principle of the brightness improving sheet according to the present invention.

5A and 5B are simulation graphs showing luminance characteristics according to incident angles.

6 is a perspective view showing various types of brightness enhancement sheets.

7 is a schematic of the model used for simulation.

8A to 8C are comparison diagrams of surface luminance characteristics through simulations.

9A to 9C are comparison diagrams of vertical light characteristics through simulations.

10 is a comparative view of viewing angle characteristics through simulation.

Claims (7)

A substrate having an upper surface and made of a transparent material; And A plurality of prismatic structures formed on an upper surface of the substrate and made of a transparent material; Wherein the prism structures extend in a first direction and are formed in a discontinuous pattern along a second direction perpendicular to the first direction, exposing an upper surface of the substrate between the prism structures. Brightness improvement sheet of LCD backlight unit. The method according to claim 1, And a pitch between the prism structures and a distance between the prism structures are all constant. The method according to claim 1, And the pitch between the prism structures and the spacing between the prism structures are not constant. The method according to claim 1, Wherein one of the pitch of the prism structures and the distance between the prism structures is constant and the other is not constant. The method according to claim 1, The cross-section of the prism structures is any one of a triangular, trapezoidal, semi-circular shape, the brightness improving sheet of the LCD backlight unit. The method according to claim 1, The size, height and angle of the prism structures are always constant, the brightness improving sheet of the LCD backlight unit. The method according to claim 1, And at least one of the size, height, and angle of the prism structures is not constant.
KR1020070095774A 2007-09-20 2007-09-20 Brightness enhancement sheet of lcd backlight unit KR20090030455A (en)

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10222533B2 (en) 2014-04-09 2019-03-05 Kookmin University Industry Academy Cooperation Foundation Backlight unit and display device comprising same
CN110068957A (en) * 2019-04-30 2019-07-30 深圳市隆利科技股份有限公司 Backlight module and LCD display device for fingerprint recognition in LCD screen
KR20200142313A (en) * 2019-06-12 2020-12-22 주식회사 엘엠에스 Opotical film for fingerprinting
KR20210055899A (en) * 2019-11-08 2021-05-18 주식회사 엘엠에스 Optical film for fingerprinting recognition
US11288486B2 (en) 2019-06-12 2022-03-29 Lms Co., Ltd. Fingerprint recognition optical film, and backlight unit and liquid crystal display device comprising the film optical

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10222533B2 (en) 2014-04-09 2019-03-05 Kookmin University Industry Academy Cooperation Foundation Backlight unit and display device comprising same
CN110068957A (en) * 2019-04-30 2019-07-30 深圳市隆利科技股份有限公司 Backlight module and LCD display device for fingerprint recognition in LCD screen
KR20200142313A (en) * 2019-06-12 2020-12-22 주식회사 엘엠에스 Opotical film for fingerprinting
US11288486B2 (en) 2019-06-12 2022-03-29 Lms Co., Ltd. Fingerprint recognition optical film, and backlight unit and liquid crystal display device comprising the film optical
KR20210055899A (en) * 2019-11-08 2021-05-18 주식회사 엘엠에스 Optical film for fingerprinting recognition

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