KR101728743B1 - Light Guiding Plate including Scattering Layer and Back Light Unit Having the Same - Google Patents

Light Guiding Plate including Scattering Layer and Back Light Unit Having the Same Download PDF

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Publication number
KR101728743B1
KR101728743B1 KR1020150065690A KR20150065690A KR101728743B1 KR 101728743 B1 KR101728743 B1 KR 101728743B1 KR 1020150065690 A KR1020150065690 A KR 1020150065690A KR 20150065690 A KR20150065690 A KR 20150065690A KR 101728743 B1 KR101728743 B1 KR 101728743B1
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KR
South Korea
Prior art keywords
light
guide plate
light guide
scattering
light source
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KR1020150065690A
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Korean (ko)
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KR20160133090A (en
Inventor
최진연
최윤석
정진영
Original Assignee
주식회사 엘엠에스
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Priority to KR1020150065690A priority Critical patent/KR101728743B1/en
Publication of KR20160133090A publication Critical patent/KR20160133090A/en
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Publication of KR101728743B1 publication Critical patent/KR101728743B1/en

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    • 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
    • G02F1/133524—Light-guides, e.g. fibre-optic bundles, louvered or jalousie light-guides
    • 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
    • G02F1/133528—Polarisers
    • 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
    • G02F1/133615—Edge-illuminating devices, i.e. illuminating from the side
    • G02F2001/133507—

Abstract

The present invention relates to a backlight unit including a light source, a diffusion sheet and a light collecting sheet, a light guide plate for transmitting light generated from the light source to the diffusion sheet, A light guide plate body which receives light emitted from the light source and transmits the light to the diffusion sheet, and a plurality of scatterers arranged between the light source and the one side of the light guide plate main body and having different refractive indexes, And a light scattering layer for scattering the light scattered by the light scattering layer and transmitting the scattered light to the light guide plate main body, wherein a plurality of the light sources are spaced apart from each other and disposed adjacent to the light scattering layer.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a light guide plate having a light scattering layer and a backlight unit having the light guide plate,

The present invention relates to a light guide plate for transmitting light generated from a light source to an upper portion thereof and a backlight unit having the light guide plate and a light scattering layer disposed adjacent to the light source and transmitting the generated light to the light guide plate main body, The present invention relates to a backlight unit.

2. Description of the Related Art In recent years, the use of flat panel display panels has been expanding.

Generally, a liquid crystal display (LCD) requires a backlight unit that provides uniform light throughout the screen, unlike a conventional CRT.

Specifically, the backlight unit is configured to provide uniform light on the rear surface of the liquid crystal display device. The LED, which is a light source, is disposed on one side of the light guide plate. Reflected light, which leaks from the light guide plate, A sheet is disposed.

In this state, the light generated by the light source is reflected upward by the light guide plate and the reflection sheet, and the reflected light is uniformly transmitted to the upper portion through the light collecting sheet.

That is, in the backlight unit, the light generated from the light source provided on the side surface is reflected upward by the light guide plate and the reflective sheet, and the reflected light is uniformly condensed through the condenser sheet.

At this time, the light source that transmits light to the light guide plate is composed of a plurality of LEDs and is spaced apart to reduce the number of LEDs in consideration of energy efficiency and thin thickness.

However, when light is received from a light source having a plurality of LEDs spaced apart from each other, light can not be uniformly transmitted to one side of the light guide plate adjacent to the light source.

1, in the conventional light guide plate 10, when a plurality of LEDs are arranged so as to be spaced apart from each other and disposed directly in contact with one side of the light guide plate, A dark portion A and a bright portion B are generated.

In this case, the brightness of the light transmitted from the light guide plate to the diffusion sheet is uneven, which results in a problem that the brightness of the liquid crystal display device is uneven.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is an object of the present invention to provide a light guide plate for a backlight unit, which has a separate light scattering layer and is provided with a plurality of spaced light sources, And a backlight unit including the light guide plate having a light scattering layer capable of uniformizing the light uniformity in the light guide plate.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not intended to limit the invention to the precise form disclosed. There will be.

According to an aspect of the present invention, there is provided a backlight unit including a light source, a diffusion sheet, and a light collecting sheet, the light guide plate transmitting light generated from the light source to the diffusion sheet, A light guide plate body disposed at a lower portion of the diffusion sheet and receiving light emitted from the light source and transmitting the light to the diffusion sheet and a plurality of scatterers having a refractive index different from that of the binder, And a light scattering layer disposed between one side of the light guide plate main body and the light source to scatter light generated from the light source and transmit the scattered light to the light guide plate main body, and the light source is disposed adjacent to the light scattering layer.

In addition, the scatterer may be configured to have a size such that mie-scattering occurs corresponding to the wavelength of light generated in the light source.

The scattering body may have a size of 0.1 to 2 탆 when the light emitted from the light source has a wavelength in a visible light region.

The light guide plate main body may include a light introducing portion having a thickness larger than a size of the light source and contacting the light scattering layer, and a light transmitting portion having a thickness smaller than that of the light introducing portion and continuously formed with the light introducing portion . ≪ / RTI >

The light scattering layer may be formed integrally with the light introducing portion, and the scattering body may be provided in the light introducing portion.

Further, the scattering body may have a spherical shape.

The light guide plate main body has a uniform thickness and is formed to be long along the lateral direction, and the light scattering layer is formed to have the same thickness as the light guide plate main body.

The light scattering layer may have the same thickness as the light guide plate main body, and may have a saw-tooth shape at one side in the light source direction along a direction perpendicular to the up-down direction or the up-down direction.

According to another aspect of the present invention, there is provided a light source for generating light by spacing a plurality of LEDs, a light guide plate according to any one of claims 1 to 8, And a light condensing sheet portion for uniformly condensing and diffusing the light diffused by the diffusion sheet in the upward direction.

The light condensing sheet portion may include an upper optical sheet having a first structured pattern in which the first unit condenser is continuously repeated with a decreasing transverse sectional area, and a second optical sheet having a cross- And a lower optical sheet having a second structured pattern in which the unit condenser is continuously repeated.

The light guide plate may further include a reflection polarizing film disposed in a laminated form with the lower optical sheet and the upper optical sheet and selectively transmitting light according to the polarization of light transmitted from below.

In order to solve the above problems, the present invention has the following effects.

First, even if a light source having a plurality of LEDs spaced apart is used, light is uniformly diffused in the main body of the light guide plate, thereby reducing the number of LEDs as a whole and increasing the light efficiency.

The effects of the present invention are not limited to the above-mentioned effects, and other effects not mentioned can be clearly understood by those skilled in the art from the description of the claims.

1 is a schematic view illustrating a state in which light is transmitted by a light guide plate included in a conventional backlight unit;
FIG. 2 is an exploded perspective view illustrating the structure of a backlight unit including a light guide plate according to an embodiment of the present invention; FIG.
FIG. 3 is a perspective view schematically showing the configuration of the light guide plate of FIG. 2; FIG.
FIG. 4 is a side view showing the internal configuration of the light guide plate of FIG. 2; FIG.
FIG. 5 is a view showing a state where light is scattered by a light scattering layer provided in the light guide plate of FIG. 2; FIG.
FIG. 6 is a view illustrating a state where light is scattered according to the size of a scatterer provided in the light scattering layer of FIG. 2; FIG.
FIG. 7 is a view illustrating a light guide plate of the light guide plate of FIG. 2 having a uniform thickness; FIG.
FIG. 8 is a view showing a modified form of the light guide plate of FIG. 2; FIG.
FIG. 9 is a view illustrating a state in which a separate reflective polarizing film is further included in the backlight unit of FIG. 2; And
10 is a view showing a state in which light is transmitted or reflected by the reflective polarizing film of FIG.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. In describing the present embodiment, the same designations and the same reference numerals are used for the same components, and further description thereof will be omitted.

In the following description, a backlight unit including a light guide plate according to an embodiment of the present invention will be described as an example applied to a flat panel liquid crystal display device such as an LCD or an LED panel. However, the present invention is not limited to this, and may be used alone, or may be a backlight unit applied to a mechanism other than that applied to a liquid crystal display, or may be a backlight unit, The present invention may be applied to any apparatus that changes the position of the object.

<Configuration>

First, referring to FIGS. 2 to 6, a schematic configuration of a backlight unit to which a light guide plate according to an embodiment of the present invention is applied will be described.

FIG. 2 is an exploded perspective view showing a configuration of a backlight unit having a light guide plate according to an embodiment of the present invention, FIG. 3 is a perspective view schematically showing the configuration of the light guide plate of FIG. 2, Fig.

And FIG. 5 is a view showing a state where light is scattered by the light scattering layer provided in the light guide plate of FIG. 2. FIG. 6 is a view showing a state where light is scattered according to the size of the scattering body provided in the light scattering layer of FIG. to be.

As shown in the figure, in forming a liquid crystal display device, a back light unit (BLU) for providing light to the liquid crystal panel must be provided. The backlight unit includes the light source 100, the light guide plate 200, the diffusion sheet 300, and the light condensing sheet unit 400.

The light source 100 generally comprises a light emitting body that emits light, and emits light from the side of the light guide plate 200 to transmit light toward the light guide plate 200.

In the present embodiment, the light source 100 is composed of a plurality of LED lights, and a plurality of the LED lights are spaced apart from each other.

As shown in this embodiment, the light source 100 is integrally formed with a separate reflection plate 110, and the light guide plate 200 to be described later is disposed on the upper surface of the reflection plate 110.

The light source 100 is provided on one side of the reflector 110 so that the light generated by the plurality of LEDs moves along the transverse direction of the reflector 110.

Here, the horizontal direction is a direction in which the light guide plate 200 is moved along the surface of the reflection plate 110 as shown in the figure, and the vertical direction is a direction in which the light guide plate 200 described later is stacked on the upper or lower surface of the reflection plate 110 Direction.

The light guide plate 200 is stacked on the upper surface of the reflection plate 110 and transmits light transmitted from the light source 100 to the upper side of the light guide plate 200. The light guide plate 200 is formed in the form of a film, .

In this embodiment, the light source 100 is disposed on one side of the light guide plate 200, and the light source 100 generates light toward the light guide plate 200. The light guide plate 200 transmits the light from the light source 100 toward the light condensing sheet unit 400.

The specific configuration of the light guide plate 200 will be described later.

The diffusion sheet 300 is disposed on the light guide plate 200 to diffuse the light transmitted from the light guide plate 200 and to transmit the diffused light to the light condensing sheet unit 400.

The light condensing sheet unit 400 is disposed on the upper side of the light guide plate 200, and condenses the transmitted light to move it upward. The light collecting sheet unit 400 includes a pair of upper optical sheets 410 and a lower optical sheet 420 formed in a laminated manner to totally transfer light from the light guide plate 200 to the upper portion.

In general, the light collecting sheet unit 400 is formed in the form of a pair of prism sheets, and is configured to condense light. Alternatively, the light collecting sheet unit 400 may be formed as a single unit or an inverted prism unit.

The light condensing sheet portion 400 according to the present embodiment includes the upper optical sheet 410 and the lower optical sheet 420 and is disposed on the upper portion of the diffusion sheet 300 in a stacked state. .

The upper optical sheet 410 is configured to have a first structured pattern 412 in which the first unit condenser whose cross sectional area decreases as it goes to the upper part is continuously repeated, and the lower optical sheet 420 has a cross- And the second unit condenser, whose upper surface is bonded to the lower surface of the upper optical sheet 410, has a second structured pattern 422 that is continuously repeated.

Here, the cross-sectional area refers to a cross-section along the lateral direction of the first structured pattern 412 or the second structured pattern 422.

Specifically, the upper optical sheet 410 includes a first base film 414 and the first structured pattern 412.

As the first base film 414, a light-transmissive film is generally used so that light incident from the bottom can be easily transmitted. The first structured pattern 412 for refracting and condensing incident light is formed on the upper surface of the first base film 414 so as to be integrated with the first base film 414.

The first structured pattern 412 is composed of a plurality of first unit condensers that are continuously formed on the upper surface of the first base film 414 and protrude upward to form a sloped surface having a smaller cross sectional area .

The first unit condenser refracts and condenses the light transmitted through the first base film 414 and transmits the light to the upper part.

In general, the first structured pattern 412 includes a plurality of prism shapes formed such that upper and lower end faces of a triangular shape extend along one direction.

The lower optical sheet 420 according to the embodiment of the present invention includes the second base film 424 and the second structured pattern 422 similarly to the upper optical sheet 410 described above .

The second structured pattern 422 is disposed on the lower surface of the upper optical sheet 410 and is formed on the upper surface of the second base film 424.

In addition, the first base film 414 and the second base film 424 may be formed of acrylic or urethane, and may have a high light transmittance so as to transmit the light transmitted from the diffusion sheet 300. It is preferable that it is made of a material.

Each of the first structured pattern 412 and the second structured pattern 422 is elongated in the transverse direction and the extension direction of the first structured pattern 412 is extended along the second structured pattern 422 The upper optical sheet 410 and the lower optical sheet 420 are stacked.

In this embodiment, the upper optical sheet 410 and the lower optical sheet 420 are arranged so that the extension directions of the first structured pattern 412 and the second structured pattern 422 are perpendicular to each other, The upper optical sheet 410 and the lower optical sheet 420 may be arranged not only in a vertical direction but also in a crossing direction.

Meanwhile, although not shown in the drawing, the first structured pattern 412 or the second structured pattern 422 may be formed to have a height varying along the extending direction without uniformity.

Accordingly, light diffused and transmitted by the diffusion sheet 300 can be more effectively condensed and transmitted to the upper direction.

The light condensing sheet portion 400 having such a structure is condensed in a direction orthogonal to the surface of the light condensing sheet portion 400 by the structured pattern formed on the upper optical sheet 410 and the lower optical sheet 420 .

However, the shapes of the first structured pattern 412 and the second structured pattern 422 formed on the upper optical sheet 410 and the lower optical sheet 420 are not limited to specific shapes, So that the configuration according to the embodiment of FIG.

As described above, a backlight unit including the light guide plate 200 according to the present invention is formed, and refracts, diffuses, and collects light generated from the light source 100 and transmits the light to the upper part.

The light guide plate 200 according to the present invention includes a light guide plate main body 210 for transmitting light generated from a light source 100 upward, And a light scattering layer 220 for diffusing light between the light source 100 and the light guide plate main body 210.

The light guide plate main body 210 has a film shape and receives light from the light source 100 provided at one side and transmits the light to the upper side.

In order to uniformly supply light transmitted from the light source 100, various types of patterns may be formed on the lower surface of the light guide plate body 210. For example, the light guide plate body 210 may be formed of an acrylic resin, which is one of transparent materials capable of transmitting light, . &Lt; / RTI &gt;

Here, the light guide plate main body 210 includes a light introducing part 214 and a light transmitting part 212 to realize a light weight and thin liquid crystal display device by reducing the thickness to have the greatest influence on the thickness of the backlight unit .

The light introducing portion 214 has a relatively larger thickness than the light source 100 and is disposed adjacent to the light scattering layer 220 described later. In this case, the light introducing portion 214 is formed to be larger than the thickness of the light source 100, as shown in the figure, so that light generated from the light source 100 can be stably received.

The light transmitting portion 212 is formed to extend from the light introducing portion 214 to have a uniform thickness in the form of a film and has a thickness D2 that is relatively smaller than the thickness D1 of the light introducing portion 214 .

Specifically, the light transmitting portion 212 has a thickness smaller than that of the light introducing portion 214, and is formed continuously along the lateral direction.

At this time, the light transmitting portion 212 is formed along the traveling direction of light emitted from the light source 100 in the form of a film along the lateral direction in the light introducing portion 214.

The light transmitting portion 212 may be formed separately from the light introducing portion 214. Alternatively, the light transmitting portion 212 may be integrally formed by extending from the light introducing portion 214 in a direction opposite to the light source 100 have.

Accordingly, the light introducing portion 214 is integrally formed with the light transmitting portion 212 by forming an inclined surface that sharply decreases in thickness from D1 to D2.

As described above, the light transmitting portion 212 has a pattern formed on the lower surface thereof, and has a uniform thickness to stably transmit and reflect the light transmitted from the light source 100 to the upper portion. As shown in FIG.

Since the light guide plate 200 has the light transmitting portion 212 having a thickness smaller than that of the light introducing portion 214 and the light introducing portion 214, the overall thickness of the light guide plate 200 can be reduced have.

The light scattering layer 220 according to the present invention is disposed between one side of the light guide plate body 210 and the light source 100 and includes a plurality of scatterers 222 having different refractive indices, 0.0 &gt; 100). &Lt; / RTI &gt;

More specifically, the light scattering layer 220 is bonded to one side of the light guide panel 210 and is disposed in the lower part of the diffusion sheet 300 in the form of a sheet together with the light guide panel main body 210.

The light source 100 is in contact with the light scattering layer 220 and receives and diffuses the light generated from the plurality of LEDs.

Here, the light scattering layer 220 includes the scatterer 222 described above, and light scattered from the light source 100 is scattered by the plurality of scatterers 222.

The light diffused by the scattering body 222 is transmitted to the light guide panel main body 210 and is transmitted to the upper part by the light guide panel main body 210.

More specifically, the light scattering layer 220 includes a light scattering layer 220 and a scattering body 222 having a refractive index different from that of the binder.

The binder is made of a general transparent resin and is configured to maintain the shape so that the plurality of scatterers (222) are spaced apart from each other. The binder is made of a material capable of minimizing the brightness reduction of light emitted from the light source do.

The binder is configured to have a refractive index different from that of the scattering body 222 so that light emitted from the light source 100 is diffused by the scattering body 222.

5, the light generated by the light source 100 is scattered by the light scattering layer 220 and is transmitted to the light guide plate main body 210. [

The light scattering layer 220 has a size greater than or equal to the thickness of the light guide panel 210 to receive light from the light source 100 as much as possible and transmit the light to the light guide panel 210 do.

The light scattering layer 220 has a thickness equal to the thickness of the light introducing portion 214 and is configured to have a thickness greater than that of the light transmitting portion 212 as shown in FIG.

 The size of the scattering body 222 according to the present invention may have a small size ranging from several hundred nanometers to several micrometers and may have a size such that mie-scattering occurs corresponding to the wavelength of light generated in the light source 100 .

Specifically, scattering is a phenomenon in which light collides with a specific particle and is scattered in various directions. It refers to a phenomenon in which waves or high-speed particle beams collide with many molecules, atoms, and particles to change the direction of motion and scatter. It occurs in gas, liquid, and solid interior, but in solid or liquid, diffuse light is synthesized and is seen more as refracted light or reflected light.

Representative scattering includes Rayleigh scattering and Mie-scattering.

First, Rayleigh scattering refers to scattering occurring when the size of particles causing scattering is very small and is smaller than the wavelength of light, which is inversely proportional to the fourth power of the wavelength of light. That is, the amount of scattered light sharply increases as the wavelength becomes longer It decreases.

As shown in FIG. 6 (a), the Rayleigh scattering causes light to scatter both forward and backward when the light collides against a specific particle.

On the contrary, non-scattering occurs when the size of a specific particle colliding with light is similar to the wavelength of light, and forward scattering is remarkable and relatively small energy is scattered backward as shown in FIG. 6 (b).

Such scattering is influenced by the density, size and shape of the particles, and particularly scattering occurs in spherical particles.

Accordingly, the scatterer 222 according to the present invention is configured such that scattering occurs in a forward scattering state in order to diffuse and transmit the light transmitted from the light source 100 to the light guide plate body 210 forward desirable.

In this embodiment, the scatterer 222 has a spherical shape and has a size corresponding to the wavelength of the visible light region so that light generated from the light source 100 can be scattered forward.

Specifically, the scattering body 222 may be formed of at least one of PDMS, ZrO 2, TiO 2, Al 2 O 3, MgO, and SiO 2, and is preferably formed in a spherical shape. Among them, PDMS particles are more advantageous because the light absorption rate (@ 550 nm) is 0.023% or less and scattering occurs more than SiO2 (0.045%) and Al2O3 (0.1%) particles.

The refractive index of the scattering body 222 is preferably 1.5 to 2.7, and the refractive index difference from the binder is preferably 0.01 to 0.7.

If the light emitted from the light source 100 is light in the visible light region, the scattering body 222 may have a size of about 0.1 to 2 mu m and a size similar to that of the visible light region. By maximizing the effect, the light emitted from the light source 100 toward the scattering body 222 can be forward scattered.

Accordingly, light directivity of the light emitted from the light source 100 is reduced and scattering occurs, so that the light uniformity of the light guide plate can be improved.

In addition, the fill factor of the scatterer 222 in the binder may vary depending on the type of the scatterer 222, and the range is preferably 10 wt% to 90 wt%.

 At this time, the haze (turbidity) can be adjusted by the filling rate of the scatterer 222, which can control the degree of light scattering. Also, the content may vary depending on the type of the scattering body 222, and in the case of PDMS particles, 15 wt% is suitable.

The light scattering layer 220 according to the present invention is disposed between the light guide plate body 210 and the light source 100 to scatter the light generated from the light source 100 forward, It is possible to minimize the occurrence of dark portions on the light guide panel main body 210. [

1, in the conventional light guide plate 200, when the light guide plate 200 is directly disposed on one side in a state where a plurality of LEDs are spaced apart from each other, A dark portion A and a bright portion B are generated on one side of the display panel 200.

In this case, the brightness of the light transmitted from the light guide plate 200 to the diffusion sheet 300 becomes uneven, and the brightness of the liquid crystal display device becomes uneven.

However, since the light scattering layer 220 is further provided as in the present invention, even if the light source 100 has a plurality of LEDs and is disposed apart from the light source 100, light generated from the light source 100 can be transmitted to the light guide plate body 210 It is possible to minimize the occurrence of dark portions in the light guide panel main body 210 by being diffused by the scattering body 222 before being transmitted.

Although not shown, the light scattering layer 220 has the same thickness as the light guide plate main body 210 and has one side in the direction of the light source 100 along the vertical direction or the vertical direction, As shown in FIG.

For example, the light scattering layer 220 may be formed as a pyramid, a prism, or a cylindrical shape so as to protrude toward the light source 100.

As described above, the light scattering layer 220 may be formed in various shapes not in a quadrangular shape, but may diffuse the light emitted from the light source 100 uniformly, (210).

<Modifications>

7 and 8, a modified form of the light scattering layer 220 in the light guide plate 200 according to the present invention will now be described.

First, FIG. 7 is a view showing a form in which the light guide plate main body in the light guide plate of FIG. 2 is formed to have a uniform thickness.

Referring to FIG. 7, the structure of the light guide plate 210 according to the present invention will be described with reference to FIG. 7. The light guide plate 210 is not provided with a separate light introducing portion 214 and has a uniform thickness.

Specifically, the light guide plate main body 210 is formed only of the light transmitting portion 212 having a uniform film thickness without the light introducing portion 214 described above.

The light scattering layer 220 is provided between one side of the light transmitting portion 212 and the light source 100.

Accordingly, the light emitted from the light source 100 is diffused by the scattering body 222 provided in the light scattering layer 220 and diffused and transmitted to the light transmitting portion 212 evenly.

The light is diffused through the light scattering layer 220 and is transmitted to the light guide panel main body 210 so that light is emitted from the light source 100 having a plurality of spaced LEDs, Light can be diffused and transmitted evenly.

8 is a view showing a modified form of the light guide plate 200 of FIG. 2. Referring to FIG.

The light scattering layer 220 is formed integrally with the light introducing portion 214 so that the light scattering body 222 is formed on the light introducing portion 214. [ May be provided.

More specifically, the light scattering layer 220 is integrally formed with the light introducing portion 214 to have a relatively larger thickness than the light transmitting portion 212, and the light transmitting portion 212 and the light source 100 .

The light scattering layer 220 has the same shape as the light introducing portion 214 and is formed to have a relatively larger thickness than the light transmitting portion 212 and the light source 100 as shown in FIG.

In addition, the light scattering layer 220 is configured to be integrally connected to the light transmitting portion 212 with a drastic reduction in thickness along the lateral direction.

Accordingly, the light scattering layer 220 is formed integrally with the light introducing portion 214, and a plurality of the scattering bodies 222 are provided therein.

<Addition of reflective polarizing film>

Next, with reference to FIGS. 9 and 10, a description will be made of a state in which a separate reflective polarizing film 500 is further included in the backlight unit having the light guide plate 200 according to the present invention.

FIG. 9 is a view illustrating a state in which a separate reflective polarizing film is further included in the backlight unit of FIG. 2, and FIG. 10 is a view illustrating a state in which light is transmitted or reflected by the reflective polarizing film of FIG.

The upper optical sheet 410 and the lower optical sheet 420 may be integrally formed on the upper optical sheet 410 so that the upper optical sheet 410 and the lower optical sheet 420 To selectively transmit the condensed light.

The reflective polarizer 500 selectively transmits light in one polarization state according to the polarization state of light and returns light having a different polarization state to the light guide plate 200. An example of such a film is a Dual Brightness Enhancement Film (DBEF).

The reflected light that does not pass through the DBEF is reflected again through the light guide plate 200 at the lower end of the BLU and then directed upward. DBEF repeats the role of reflecting the remaining light after passing only polarized light.

By repeating this process, only the desired polarized light is emitted upward, so that the loss of emitted light is reduced and the brightness of the display module is increased.

10, the reflective polarizer film 500 is stacked on the upper optical sheet 410 and disposed on the lower optical sheet 420 and the upper optical sheet 410, And the condensed light passes through the reflective polarizer film 500. Here, the light directed to the reflective polarizer film 500 is a mixture of polarized lights of different polarities, and the light of P1 having the polarized light of the region transmitted by the reflective polarizer film 500 and the light of the reflective polarizer film 500 And the light of P2 having the polarization of the non-transmissive region.

As shown in the figure, the light passing through the upper optical sheet 410 and the lower optical sheet 420 is in a mixed state of P1 and P2, but the reflective polarizing film 500 transmits only the P1 light, Direction.

Therefore, the light of P1 is emitted to the outside, but the light of P2 is reflected and returned to the bottom, and is reflected by the upper optical sheet 410, the lower optical sheet 420, the light guide plate 200, Through this process, the light of the polarized light P2 is changed to a state suitable for transmission of the reflective polarizing film 500 through such repetition.

By providing the reflective polarizer film 500 as described above, it is possible to reduce the loss of light and increase the brightness of the liquid crystal display device by emitting light having a desired refraction angle and wavelength to the upper portion.

The reflective polarizing film 500 may be stacked on the upper optical sheet 410 and may be disposed between the upper optical sheet 410 and the lower optical sheet 420 It is possible.

It will be apparent to those skilled in the art that the present invention can be embodied in other specific forms without departing from the spirit or scope of the invention as defined in the appended claims. It is obvious to them. Therefore, the above-described embodiments are to be considered as illustrative rather than restrictive, and the present invention is not limited to the above description, but may be modified within the scope of the appended claims and equivalents thereof.

100: light source 110: reflector
200: light guide plate 210: light guide plate main body
220: light scattering layer 300: diffusion sheet
400: condensing sheet part 500: reflective polarizing film

Claims (11)

A light guide plate for transmitting light generated from the light source to the diffusion sheet in a backlight unit including a light source, a diffusion sheet, and a light condensing sheet,
A light guide plate body formed in a film form and disposed at a lower portion of the diffusion sheet, for receiving light generated from the light source provided at one side and transferring the light to the diffusion sheet; And
A binder and a PDMS material and has a refractive index different from that of the binder and includes a plurality of scattering bodies provided in the binder in an amount of 10 to 90 wt%, the scattering body being disposed between one side of the light guide plate body and the light source, A light scattering layer for scattering light and transmitting the scattered light to the light guide panel main body; / RTI &gt;
Wherein the light guide plate main body has a light guide part having a relatively larger thickness than the light source and dispersed in the scattering member to be integrally formed with the light scattering layer and a light guide part having a relatively smaller thickness than the light guide part, And a light transmitting portion formed,
Wherein the light source is disposed adjacent to the light scattering layer,
Wherein the scattering body is dispersed and disposed inside the light guide portion. The method according to claim 1,
Wherein the scattering body comprises:
Wherein the light-scattering layer has a size such that mie-scattering occurs corresponding to a wavelength of light generated in the light source. 3. The method of claim 2,
Wherein the scattering body comprises:
Wherein the light scattering layer has a size of 0.1 to 2 占 퐉 when the light emitted from the light source has a wavelength of a visible light region. delete delete The method according to claim 1,
Wherein the scattering body comprises:
Wherein the light-scattering layer has a spherical shape. delete The method according to claim 1,
The light-
Wherein the light guide plate has the same thickness as the light guide plate main body and has a sawtooth shape at one side in the light source direction along a vertical direction or a direction perpendicular to the up and down direction. A plurality of LEDs spaced apart from each other to generate light;
A light guide plate according to any one of claims 1 to 3, 6, and 8;
A diffusion sheet laminated on the light guide plate and diffusing light transmitted from the lower portion evenly; And
A light condensing sheet portion for uniformly condensing and transmitting light diffused by the diffusion sheet in an upward direction;
. 10. The method of claim 9,
The light-
An upper optical sheet having a first structured pattern in which a first unit condenser whose transverse area decreases as it goes up is continuously repeated; And
A lower optical sheet having a second structured pattern in which a second unit condenser, which is reduced in cross-sectional area toward the upper portion and is joined to the upper optical sheet, is continuously repeated; . 11. The method of claim 10,
Further comprising a reflective polarizing film disposed in a laminated form with the lower optical sheet and the upper optical sheet and selectively transmitting light according to a polarization of light transmitted from the lower portion.
KR1020150065690A 2015-05-12 2015-05-12 Light Guiding Plate including Scattering Layer and Back Light Unit Having the Same KR101728743B1 (en)

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Publication number Priority date Publication date Assignee Title
KR20210121699A (en) * 2020-03-31 2021-10-08 주식회사 엘엠에스 Optical film to reduce hotspots

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Publication number Priority date Publication date Assignee Title
CN110107861A (en) * 2019-06-05 2019-08-09 华域视觉科技(上海)有限公司 Vehicular illumination device

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JP2007502010A (en) * 2003-05-16 2007-02-01 スリーエム イノベイティブ プロパティズ カンパニー Method for stacking surface structured optical films
JP2008016429A (en) * 2006-06-30 2008-01-24 Lg Philips Lcd Co Ltd Backlight assembly and liquid crystal display
JP2008053009A (en) * 2006-08-23 2008-03-06 Nidec Copal Corp Light guide plate, and surface light emitting device

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JP2007502010A (en) * 2003-05-16 2007-02-01 スリーエム イノベイティブ プロパティズ カンパニー Method for stacking surface structured optical films
JP2008016429A (en) * 2006-06-30 2008-01-24 Lg Philips Lcd Co Ltd Backlight assembly and liquid crystal display
JP2008053009A (en) * 2006-08-23 2008-03-06 Nidec Copal Corp Light guide plate, and surface light emitting device

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Publication number Priority date Publication date Assignee Title
KR20210121699A (en) * 2020-03-31 2021-10-08 주식회사 엘엠에스 Optical film to reduce hotspots
KR102343050B1 (en) * 2020-03-31 2021-12-27 주식회사 엘엠에스 Optical film to reduce hotspots

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