KR102053597B1 - Liquid crystal display device - Google Patents

Liquid crystal display device Download PDF

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Publication number
KR102053597B1
KR102053597B1 KR1020120143612A KR20120143612A KR102053597B1 KR 102053597 B1 KR102053597 B1 KR 102053597B1 KR 1020120143612 A KR1020120143612 A KR 1020120143612A KR 20120143612 A KR20120143612 A KR 20120143612A KR 102053597 B1 KR102053597 B1 KR 102053597B1
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KR
South Korea
Prior art keywords
light
guide plate
light guide
liquid crystal
pattern
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KR1020120143612A
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Korean (ko)
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KR20140075356A (en
Inventor
송영기
강재경
Original Assignee
엘지디스플레이 주식회사
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Priority to KR1020120143612A priority Critical patent/KR102053597B1/en
Publication of KR20140075356A publication Critical patent/KR20140075356A/en
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Publication of KR102053597B1 publication Critical patent/KR102053597B1/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
    • G02B5/00—Optical elements other than lenses
    • G02B5/04—Prisms
    • G02B5/045—Prism arrays
    • 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
    • G02B6/0038—Linear indentations or grooves, e.g. arc-shaped grooves or meandering grooves, extending over the full length or width of the light guide
    • 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
    • G02B6/0051—Diffusing 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
    • G02F1/133615—Edge-illuminating devices, i.e. illuminating from the side

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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)
  • Planar Illumination Modules (AREA)

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display, and more particularly, to a liquid crystal display having a high brightness and a light weight and a thin shape.
A feature of the present invention is to form a diffusion layer and an intaglio prism acid pattern on the upper and lower surfaces of the light guide plate, and an embossed prism acid pattern corresponding to the intaglio prism acid pattern formed on the lower surface of the light guide plate on the upper surface of the reflecting plate. To form.
As a result, the configuration of the optical sheet on the upper part of the light guide plate can be omitted, and light loss can be prevented from being generated by the optical sheet, thereby providing a high luminance of light to the liquid crystal panel.
In addition, there are many components of the backlight unit to hinder the light weight and thinness of the liquid crystal display device, or to reduce the efficiency of the process due to an increase in the working time in the modular process of the liquid crystal display device. The device can be provided, and the working time can be shortened, improving the efficiency of the process.

Description

Liquid crystal display device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display, and more particularly, to a liquid crystal display having a high brightness and a light weight and a thin shape.

In line with the recent information age, the display field has also been rapidly developed, and a liquid crystal display device (FPD) as a flat panel display device (FPD) having the advantages of thinning, light weight, and low power consumption in response to this has been developed. LCD, plasma display panel device (PDP), electroluminescence display device (ELD), field emission display device (FED), etc. : It is rapidly replacing CRT.

Among them, liquid crystal display devices are used most actively in the field of notebooks, monitors, TVs, etc. because of their excellent contrast ratio and high contrast ratio, and liquid crystal display devices do not have their own light emitting elements. Will be required.

Accordingly, a backlight unit having a light source is provided on a rear surface of the liquid crystal panel to irradiate light toward the front of the liquid crystal panel, thereby realizing an image of identifiable luminance.

Meanwhile, a general backlight unit is classified into a side light method and a direct type method according to an arrangement of light sources. The side light method is a structure in which one or a pair of light sources is disposed at one side of the light guide plate. It has, or two or two pairs of light sources have a structure arranged on each side of the light guide plate, the direct type has a structure in which several light sources are arranged under the optical sheet.

Here, the side light method is easier to manufacture than the direct type method, and has the advantages of lighter weight and lower power consumption than the direct type.

1 is an exploded perspective view of a side light type backlight unit.

As shown in the drawing, the backlight unit 20 includes a white or silver reflecting plate 25 and a light emitting plate 23 mounted on the LED assembly 29 and the reflecting plate 25, which are light sources arranged along the longitudinal direction of one side thereof. The optical sheet 21 is mounted on the light guide plate 23.

The LED assembly 29 is located at one side of the light guide plate 23 so as to face the light incident surface of the light guide plate 23. The LED assembly 29 includes a plurality of LEDs 29a and a plurality of LEDs 29a at regular intervals. It includes a PCB (29b) spaced apart.

The optical sheet 21 on the light guide plate 23 diffuses or condenses the light passing through the light guide plate 23 to inject a more uniform surface light source into the liquid crystal panel. The first and second diffusion sheets 21a and 21c may be used. And a light collecting sheet 21b.

Here, the light collecting sheets 21b are arranged adjacent to each other in a band shape so that a plurality of patterns having a shape of repeating hills and valleys are arranged in a row to protrude from the support layer, so that the light collecting sheets 21b are positioned above the light collecting sheets 21b. The liquid crystal panel collects high brightness light.

In addition, the first diffusion sheet 21a is positioned directly on the light guide plate 23, and serves to adjust the direction of light to propagate toward the light collecting sheet while dispersing light incident through the light guide plate 23. The sheet 21c is positioned above the light collecting sheet 21b to adjust the direction of the light so that the light travels toward the liquid crystal panel while dispersing the light collected through the light collecting sheet 21b once again.

Meanwhile, as shown in FIG. 2A, the LED assembly 29, which is a light source, is arranged along one edge of the light guide plate 23, so that light emitted from the light guide plate 23 is opposite to the side edge where the LED assembly 29 is located. The light is refracted in the direction.

Accordingly, the light emitted from the side of the light guide plate 23 by placing the optical sheet 21 made of the light collecting sheet 21b and the first and second diffusion sheets 21a and 21c on the light guide plate 23 may cause the liquid crystal panel. Be guided toward

FIG. 2B is a comparison graph in which the amount of light emitted from the backlight unit 20 including the optical sheet 21 and the amount of light emitted from the light guide plate 23 are measured for each position, and the horizontal axis is 0 as the front of the light guide plate 23. The position angle at which light is emitted is shown, and the vertical axis is a result of measuring the amount of light emitted from the backlight unit 20 on the basis of 1.

Referring to FIG. 2B, it can be seen that the amount of light emitted from the light guide plate 23 emits a greater amount of light from the side than in front of the light guide plate 23, and the light emitted from the light guide plate 23 is converted into an optical sheet ( By processing through 21), it can be seen that a large amount of light is emitted to the front of the light guide plate 23.

Therefore, the side light type backlight unit 20 including the light guide plate 23 is essentially a configuration in which a plurality of optical sheets 21 on the light guide plate 23 is interposed.

However, as the plurality of optical sheets 21 are positioned above the light guide plate 23, the light efficiency is lowered.

That is, when the amount of light emitted from the LED 29a of the LED assembly 29 is 100%, the amount of light incident on the liquid crystal panel is about 70 to 80%, and the plurality of optical sheets positioned on the light guide plate 23 ( This is because absorption of some light and low efficiency of each optical sheet 21 are laminated by 21), and the overall light utilization efficiency is lowered.

In addition, the use of a plurality of optical sheets 21 inhibits the thinness and light weight of the liquid crystal display device, and increases the working time in the modularization process of the liquid crystal display device, resulting in a problem that the efficiency of the process is lowered.

The present invention has been made to solve the above problems, and a first object of the present invention is to provide a liquid crystal display device having improved light efficiency, and a second object of the present invention is to provide a high brightness liquid crystal display device.

In addition, a third object of the present invention is to reduce the assembly time and the material cost during the modularization process of the liquid crystal display device while realizing the light weight and thinness of the liquid crystal display device.

In order to achieve the above object, the present invention is a liquid crystal panel; A light guide plate positioned below the liquid crystal panel, having a diffusion layer formed on an upper surface corresponding to the liquid crystal panel, and having a negative prism acid pattern formed on a lower surface thereof; A reflector plate disposed below the light guide plate and having an embossed prism pattern formed on an upper surface of the light guide plate; And an LED assembly arranged along a light receiving surface of the light guide plate, wherein the engraved prism acid pattern is configured to reduce the angle of the refracted light emitted from the lower part of the light guide plate to a normal line perpendicular to the light guide plate. The prism acid pattern provides a liquid crystal display device in which an angle formed between the reflected light reflected by the embossed prism acid pattern and the normal line is reduced.

At this time, the intaglio prism acid pattern is formed in a band shape in which peaks and valleys are repeated along the longitudinal direction of the LED assembly, and the first inclined surface of the short side facing the one direction in which the LED assembly is located is opposite to the one direction. The second inclined surface of the long side toward the other direction, wherein the first inclined surface is an angle formed with the lower surface of the light guide plate is greater than the total reflection critical angle inside the light guide plate and less than 90 degrees.

The second inclined surface has an angle of 1 to 3 degrees with the lower surface of the light guide plate, and the intaglio prism pattern has a height of 5 to 10 μm.

At this time, the embossed prism acid pattern has a band shape in which peaks and valleys are repeated along the longitudinal direction of the LED assembly, and the third inclined surface of the long side facing one direction in which the LED assembly is located is opposite to the one side in the one direction. And a fourth inclined surface of the short side facing the other direction, wherein the third inclined surface has an angle θ3 of the upper surface of the reflector plate θ3 = 1/2 (θ1-θ4) (θ1 is a lower surface of the light guide plate and the An angle formed by the first inclined plane, θ4, satisfies an angle formed by a normal perpendicular to the first inclined plane and light refracted by the first inclined plane.

The embossed prism acid pattern has a height of 10 to 40 μm, and the embossed prism acid pattern has a size 2 to 4 times larger than that of the engraved prism acid pattern.

In addition, the diffusion layer may include a light diffusion component including a bead, or a fine pattern may be formed, a cover bottom configured to be in close contact with the guide panel and the guide panel surrounding the edge of the liquid crystal panel, and the edge of the liquid crystal panel. The cover includes a top cover that is assembled to the guide panel and cover bottom assembly.

As described above, according to the present invention, the diffusion layer and the negative prism acid pattern are formed on the upper and lower surfaces of the light guide plate, and the embossed prism acid pattern formed on the lower surface of the light guide plate is formed on the upper surface of the reflector. By forming the prism acid pattern of the shape, the configuration of the optical sheet on the upper part of the light guide plate can be omitted, thereby preventing light loss from being generated by the optical sheet, thereby providing a high luminance of light to the liquid crystal panel. It has an effect.

In addition, there are many components of the backlight unit to hinder the light weight and thinness of the liquid crystal display device, or to reduce the efficiency of the process due to an increase in the working time in the modular process of the liquid crystal display device. There is an effect to provide a device, it is possible to reduce the working process time has the effect of improving the efficiency of the process.

1 is an exploded perspective view of a side light backlight unit.
FIG. 2A is a cross-sectional view illustrating a traveling path of light exiting the light guide plate of FIG. 1. FIG.
Figure 2b is a comparison graph measuring the amount of light emitted from the backlight unit including the optical sheet and the amount of light emitted from the light guide plate for each position.
3 is an exploded perspective view of a liquid crystal display according to an exemplary embodiment of the present invention.
4 is an exploded perspective view of the liquid crystal panel of FIG. 3.
5 is an exploded perspective view of the backlight unit of FIG. 3;
FIG. 6A is a schematic cross-sectional view of the cross section of FIG. 5; FIG.
FIG. 6B is an enlarged view of FIG. 6A.
FIG. 7 is a cross-sectional view schematically illustrating a process of light of a liquid crystal display according to an exemplary embodiment of the present invention. FIG.
8A is a simulation result of measuring the luminance of the backlight unit of the present invention.
Figure 8b is a graph measuring the amount of light emitted from the backlight unit of the present invention by position.

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

3 is an exploded perspective view of a liquid crystal display according to an exemplary embodiment of the present invention, and FIG. 4 is an exploded perspective view of the liquid crystal panel of FIG. 3.

As illustrated, the liquid crystal display device includes a liquid crystal panel 110, a backlight unit 120, a guide panel 130, a cover bottom 150, and a top cover 140.

In this case, for convenience of description, the direction on the drawing is defined, and the backlight unit 120 is disposed behind the liquid crystal panel 110 under the premise that the display surface of the liquid crystal panel 110 faces the front side, The cover bottom 150, which is in close contact with the back surface of the backlight unit 120 in a state in which the rectangular frame-shaped guide panel 130 is worn, is integrated by being integrated in front and rear.

Let's take a closer look at each of these.

First, the liquid crystal panel 110 will be described in more detail with reference to FIG. 3, which is an exploded perspective view of the liquid crystal panel 110. A plurality of gate lines 111a may be formed on one surface of the first substrate 112 called a lower substrate or an array substrate. ) And the data line 111b vertically and horizontally cross each other to define the pixel P. The thin film transistor T is provided at the intersection of these two lines and is connected one-to-one with the transparent pixel electrode 113a provided in each pixel region P. FIG.

In addition, the second substrate 114 facing the first substrate 112 with the liquid crystal layer 160 therebetween is called an upper substrate or a color filter substrate, and one surface of the first substrate 112 is The grid-like black matrix 118 covering the pixel region P to expose only the pixel electrode 113a while covering the non-display elements such as the gate line 111a, the data line 111b, and the thin film transistor T is formed. It is composed.

In addition, transparent common electrodes covering R (red), G (green), and B (blue) color filters 115 and all of them are sequentially arranged to correspond to each pixel region P in the lattice. (113b).

First and second polarizing plates 119a and 119b for selectively transmitting only specific light are attached to an outer surface of each of the first second substrates 112 and 114.

In addition, the gate and the data printed circuit board 117 are connected through at least one edge of the liquid crystal panel 110 via a connecting member 116 such as a flexible printed circuit board, so that the side surface or the cover of the guide panel 130 is modularized. It is folded to the back of the bottom 150 is in close contact.

At this time, although not clearly shown in the drawings, the upper and lower alignment layers for determining the initial molecular alignment direction of the liquid crystal are interposed between the two substrates 112 and 114 and the liquid crystal layer 160. A seal pattern (not shown) is formed along the edges of both substrates 112 and 114 to prevent leakage of the liquid crystal layer 160 filled between the two substrates 112 and 114.

Accordingly, the liquid crystal panel 110 is turned on by the thin film transistor T selected for each gate line 111a by the on / off signal of the thin film transistor T that is scanned and transferred to the gate line 111a. When on, the image signal of the data line 111b is transmitted to the corresponding pixel electrode 113a, and the arrangement direction of the liquid crystal molecules is changed by the electric field between the pixel electrode 113a and the common electrode 113b. The difference in transmittance is shown.

In addition, the liquid crystal display according to the present invention includes a backlight unit 120 for supplying light from the rear surface of the liquid crystal panel 110 so that the difference in transmittance of the liquid crystal panel 110 is expressed to the outside.

The backlight unit 120 includes an LED assembly 129 arranged along at least one edge length direction of the guide panel 130, a reflecting plate 220, and a light guide plate 210 mounted on the reflecting plate 220. .

The LED assembly 129 is a light source of the backlight unit 120 and includes a plurality of LEDs 129a and a PCB 129b on which the plurality of LEDs 129a are mounted at regular intervals.

In this case, the light guide plate 210 includes a diffusion layer 213 on an upper surface and an intaglio prism pattern 215 having a specific shape on the lower surface 211d (see FIG. 5), thereby incident from the LED 129a. The light is propagated through the light guide plate 210 by a plurality of total reflections so that the light is spread evenly into the light guide plate 210, and at the same time, some light is emitted toward the reflector plate 220 positioned below the light guide plate 210. .

The reflective plate 220 reflects the light passing through the lower surface 211d (see FIG. 5) of the light guide plate 210 toward the liquid crystal panel 110 to provide the surface light source of high luminance to the liquid crystal panel 110.

At this time, the reflective plate 220 according to the embodiment of the present invention and the intaglio prismatic pattern 215 formed on the lower surface (211d (see FIG. 5)) of the light guide plate 210 on the upper surface (221, Figure 5) It further includes a corresponding prism-shaped pattern 225 of a specific shape.

In the backlight unit 120, light emitted from the LED 129a is incident into the light guide plate 210 through the light incidence surface 211a (see FIG. 5) of the light guide plate 210, and the incident light is reflected by a plurality of total reflections. As it travels in the light guide plate 210 and spreads evenly to a large area of the light guide plate 210, the light emitting plate 210 is disposed on the lower surface 211d (see FIG. 5) of the light guide plate 210 and the upper surface 221 (see FIG. 5) of the reflecting plate 220. By allowing the formed patterns 215 and 225 to emit a uniform surface light source of high brightness toward the liquid crystal panel 110, the liquid crystal panel 110 finally displays an image.

We will discuss this in more detail later.

The liquid crystal panel 110 and the backlight unit 120 are modularized through the top cover 140, the guide panel 130, and the cover bottom 150. The top cover 140 has upper and side edges of the liquid crystal panel 110. A rectangular frame having a cross section bent in a shape of “a” so as to cover the upper surface of the top cover 140 is opened to display an image implemented in the liquid crystal panel 110.

In addition, the cover bottom 150 on which the liquid crystal panel 110 and the backlight unit 120 are seated, and which is the basis for assembling the entire structure of the liquid crystal display device, has a rectangular plate shape and its edge is vertically bent at a predetermined height. .

The guide panel 130 having a rectangular frame shape seated on the cover bottom 150 and surrounding the edges of the liquid crystal panel 110 and the backlight unit 120 is combined with the top cover 140 and the cover bottom 150.

In this case, the top cover 140 may also be referred to as a case top or a top case, and the guide panel 130 may also be referred to as a support main or main support, and a mold frame, and the cover bottom 150 may be referred to as a bottom cover or a lower cover. It is also built.

Meanwhile, in order to implement a light weight and thin liquid crystal display device, the top cover 140 and the cover bottom 150 are removed, and the liquid crystal panel 110 and the backlight are formed through the adhesive tape (not shown) and the guide panel 130. Unit 120 may be modular. This can reduce material costs.

In the above-described liquid crystal display of the present invention, the diffusion layer 213 and the intaglio prism pattern 215 are formed on the upper and lower surfaces 211c and 211d of the light guide plate 210 of the backlight unit 120. And an embossed prism mountain corresponding to the intaglio prism mountain pattern 215 formed on the lower surface 211d (see FIG. 4) of the light guide plate 210 on the upper surface 221 (see FIG. 4) of the reflecting plate 220. By forming the pattern 225, high luminance light is provided to the liquid crystal panel 110.

That is, in the liquid crystal display of the present invention, the light incident on the light guide plate 210 is uniformly processed into a high quality surface light source even without a plurality of optical sheets (21 in FIG. 1) being disposed on the light guide plate 210. It is provided to the panel 110.

As a result, light loss may be prevented from occurring due to the optical sheet (21 in FIG. 1), thereby providing a surface light source having high luminance to the liquid crystal panel.

In addition, there are many components of the backlight unit 120 to hinder the light weight and thinness of the liquid crystal display device, or to increase the work process time in the modularization process of the liquid crystal display device. The liquid crystal display device of the present invention can be provided, and the working process time can be reduced, thereby improving the efficiency of the process.

That is, the present invention can provide an efficient backlight unit 120 with excellent performance.

This will be described in more detail with reference to FIGS. 5 and 6A through 6B.

FIG. 5 is an exploded perspective view of the backlight unit of FIG. 3, FIG. 6A is a cross-sectional view schematically illustrating the cross section of FIG. 5, and FIG. 6B is an enlarged view of FIG. 6A.

As shown, the backlight unit 120 includes a white or silver reflector 220 seated on the cover bottom (150 of FIG. 3), and an LED assembly 129 which is a light source arranged along a longitudinal direction of one side thereof. The light guide plate 210 is mounted on the reflector plate 220.

The LED assembly 129 is located at one side of the light guide plate 210 so as to face the light incident surface 211a of the light guide plate 210, and the LED assembly 129 includes a plurality of LEDs 129a and a plurality of LEDs 129a. Includes a PCB 129b which is mounted at a predetermined interval apart.

In this case, the plurality of LEDs 129a emit light having red (R), green (G), and blue (B) colors toward the light incident surface 211a of the light guide plate 210, respectively. By lighting the LEDs 129a at once, white light by color mixing can be realized.

In particular, recently, in order to improve luminous efficiency and luminance, a blue LED 129a including a blue LED chip having excellent luminous efficiency and luminance is used, and as a phosphor, 'cerium doped yttrium aluminum garnet (YAG: Ce)', In other words, a blue LED 129a made of yellow phosphor is used.

The blue light emitted from the LED 129a is transmitted through the phosphor and mixed with the yellow light emitted by the phosphor, thereby realizing white light.

In addition to the LED assembly 129, a fluorescent lamp such as a cold cathode fluorescent lamp or an external electrode fluorescent lamp may be used.

The light guide plate 210 to which light emitted from the plurality of LEDs 129a is incident is spread evenly to a large area of the light guide plate 210 while the light incident from the LED 129a is propagated through the light guide plate 210 by a plurality of total reflections. The surface light source is provided to the liquid crystal panel 110 of FIG. 3.

Accordingly, the light guide plate 210 may be formed of a plastic material such as polymethylmethacrylate (PMMA), which is one of transparent materials capable of transmitting light, or polycarbonate (PC). It is manufactured in a flat type.

The light guide plate 210 is excellent in transparency, weather resistance, and colorability to induce light diffusion when light is transmitted.

The light guide plate 210 connects the light incident surface 211a corresponding to the LED assembly 129, the light incident surface 211b on the opposite side thereof, and connects the light incident surface 211a and the light incident surface 211b to emit light. It consists of a surface 211c, a lower surface 211d facing the reflecting plate 220 and both side surfaces 211e and 211f facing each other.

In addition, a diffusion layer 213 for diffusing light is provided on the upper surface 211c of the light guide plate 210, and the diffusion layer 213 includes a light diffusion component such as a bead or does not include beads. It may be configured by forming a fine pattern on the diffusion layer 213.

Through this, the diffusion layer 213 diffuses the light by refracting and scattering the incident light, and serves to emit uneven light passing through the light guide plate 210 as uniform light.

At this time, the bead is included in the binder resin, the bead is characterized in that the light can be partially prevented by dispersing the light incident on the diffusion layer 213.

Here, as the binder resin, the transparency is high, the light transmittance is excellent and the viscosity is easy to be adjusted. For example, acrylic, urethane, epoxy, vinyl, polyester, polyamide resin, or the like can be used.

In addition, the diffusion layer 213 that does not contain beads has a feature that can adjust the light scattering angle according to the shape of the micropattern, the micropattern has a variety of elliptical pattern (elliptical pattern), polygonal pattern (polygon pattern) By using a hologram pattern, the light incident by the interference pattern is refracted in the asymmetrical direction so that the collected light can be diffused at a more inclined angle.

As a result, light is dispersed through the diffusion layer 213 to prevent the light from being partially concentrated.

In addition, the lower surface 211d of the light guide plate 210 includes a pattern of a specific shape in order to implement a uniform surface light source and to supply high-brightness light to the liquid crystal panel (110 of FIG. 3), the pattern of which is a light guide plate 210. Are arranged adjacent to each other in the shape of a band across the side surfaces 211e and 211f along the longitudinal direction of the light incident surface 211a of the plurality of concave prism mountain patterns 215 in which the hills and valleys are repeated. Are arranged. As shown in FIG. 6B, the intaglio prism mountain pattern 215 is formed to have a height h1 of 5 to 10 μm, and the first inclined surface 215a of the short side is formed on the light incident surface 211a of the light guide plate 210. The second inclined surface 215b of the long side is formed to face the incoming light incident surface 211b of the light guide plate 210.

Here, the first inclined surface 215a of the short side of the intaglio prism pattern 215 has an angle greater than or equal to the total reflection critical angle θi within the lower surface 211d of the light guide plate 210 and the light guide plate 210 and less than or equal to 90 degrees. The second inclined surface 215b of the long side is formed to have an angle θ2 of 1 to 3 degrees with the lower surface 211d of the light guide plate 210.

In the prism mountain pattern 215, the first inclined surface 215a forms the lower exit surface of the light guide plate 210.

That is, some of the light emitted from the LED 129a of the LED assembly 129 and incident into the light guide plate 210 through the light incident surface 211a of the light guide plate 210 is a first inclined surface of the prism mountain pattern 215. The light is refracted through 215a and exits to the lower part of the light guide plate 210.

In addition, some of the light incident into the light guide plate 210 is totally reflected by the second inclined surface 215b of the intaglio prism mountain pattern 215 to travel inside the light guide plate 215 and into the light guide plate 210. Spread evenly.

At this time, the light emitted to the lower portion of the light guide plate 210 is reflected by the reflecting plate 220 positioned below the light guide plate 210 to be emitted to the front of the light guide plate 210, for this purpose, the upper surface of the reflecting plate 220 An embossed prism pattern 225 is formed at 221 to correspond to the intaglio prism mountain pattern 215 formed on the lower surface 211d of the light guide plate 210.

That is, the reflecting plate 220 is in the same direction as the intaglio prism pattern 215 formed on the lower surface 211d of the light guide plate 210 on the upper surface 221 facing the lower surface 211d of the light guide plate 210. By adjacently arranged in a band shape that traverses, a plurality of embossed prismatic pattern 225 in the form of repeating the peaks and valleys are arranged in a row to protrude.

The embossed prism acid pattern 225 has a height h2 of 10 to 40 μm. The embossed prism acid pattern 225 has an overall size formed on the lower surface 211d of the light guide plate 210. It is about 2 to 4 times larger than the intaglio prism pattern 215.

The long side third inclined surface 225a is formed to face one direction toward the LED assembly 129, and the short side fourth inclined surface 225b is formed to face the other direction on the opposite side thereof.

Here, the third inclined surface 225a of the long side of the embossed prism mountain pattern 225 is the first inclined surface 215a of the short side of the intaglio prism mountain pattern 215 formed on the lower surface 211d of the light guide plate 210. It is formed to have an angle (θ3) corresponding to), which is formed to satisfy the following equation (1).

[theta] 3 = 1/2 ([theta] 1- [theta] 4). … … Formula (1)

Here, θ1 is an angle greater than or equal to the total reflection critical angle θi and less than 90 degrees in the lower surface 211d of the light guide plate 210, and θ4 is an intaglio formed in the lower surface 211d of the light guide plate 210. The angle of refraction of light refracted by the first inclined surface 215a on the short side of the prismatic mountain pattern 215, and is formed by the normal perpendicular to the first inclined surface 215a and the light refracted by the first inclined surface 215a. to be.

Accordingly, light that is refracted through the first inclined surface 215a, which is the lower exit surface of the light guide plate 210, and exits to the bottom of the light guide plate 210, is formed by the embossed prismatic pattern 225 of the reflective plate 220. 210 is reflected toward the front.

Accordingly, the liquid crystal display of the present invention provides a uniform surface light source of high brightness to the liquid crystal panel 110 (see FIG. 3) through the light emitted toward the front of the light guide plate 210.

That is, the liquid crystal display of the present invention is processed to a high quality uniform surface light source without providing a plurality of optical sheets (21 in FIG. 1) on the light guide plate 210 to provide the liquid crystal panel (110 in FIG. 3). As a result, light loss can be prevented from being generated by the optical sheet (21 in FIG. 1), and a high amount of light can be provided to the liquid crystal panel (110 in FIG. 3).

FIG. 7 is a cross-sectional view schematically illustrating a process of light of a liquid crystal display according to an exemplary embodiment of the present invention.

As shown, light emitted from the plurality of LEDs 129a of the LED assembly 129 is incident into the light guide plate 210 through the light incident surface 211a of the light guide plate 210, and at this time, inside the light guide plate 210. The incident light is totally reflected several times in the light guide plate 210 and is evenly spread in a wide area of the light guide plate 210 while traveling in the light guide plate 210.

At this time, an intaglio prism pattern formed on the lower surface 211d of the light guide plate 210 at a critical angle (θi of FIG. 6B), which is totally reflected in the light guide plate 210 and propagates in the light guide plate 210. The light irradiated onto the first inclined surface 215a of the 215 is refracted through the first inclined surface 215a and emitted to the lower portion of the light guide plate 210.

In this case, the angle of the first inclined surface 215a to form a light emitted from the lower portion of the light guide plate 210 through the first inclined surface 215a with a normal line perpendicular to the light guide plate 210 is reduced.

The light exiting to the lower portion of the light guide plate 210 is directed to the light guide plate 210 by an embossed prism pattern 225 formed on the upper surface 221 of the reflective plate 220 positioned below the light guide plate 210. Will be reflected.

In this case, the reflected light reflected by the embossed prism pattern 225 may further reduce the angle formed by the normal to the light guide plate 210.

Therefore, the light reflected toward the front of the light guide plate 210 is transmitted through the light guide plate 210 perpendicular to the light guide plate 210 in the process of passing through the light guide plate 210, and to the upper surface 211c of the light guide plate 210. Diffusion is performed by the diffusion layer 213 formed to exit the light guide plate 210.

The light guide plate 210 is irradiated to a lower surface 211d of the light guide plate 210 than the first inclined surface 215a of the intaglio prism pattern 215 of the light guide plate 210 at a critical angle (θi of FIG. 6B) or more. The light emitted to the lower portion is also reflected toward the light guide plate 210 by the embossed prism mountain pattern 225 formed on the upper surface 221 of the reflector plate 220, and is emitted toward the front of the light guide plate 210.

Accordingly, the liquid crystal display of the present invention provides a uniform surface light source of high brightness to the liquid crystal panel 110 through the light emitted toward the front of the light guide plate 210.

That is, in the liquid crystal display of the present invention, the light incident on the light guide plate 210 is perpendicular to the light guide plate 210 without the plurality of optical sheets (21 in FIG. 1) interposed on the light guide plate 210. ) To be emitted toward the front, and processed into a uniform surface light source of high quality to be provided to the liquid crystal panel 110.

Through this, the configuration of the optical sheet (21 in FIG. 1) of the upper portion of the light guide plate 210 can be omitted, it is possible to prevent the light loss caused by the optical sheet (21 in FIG. 1). Therefore, the light amount having high luminance can be provided to the liquid crystal panel 110.

In addition, there are many components of the backlight unit (120 of FIG. 5), which hinders the light weight and thinness of the liquid crystal display device or increases the working process time in the modularization process of the liquid crystal display device. It is possible to provide a light weight and thin liquid crystal display device, and to reduce the working time, thereby improving the efficiency of the process.

8A is a simulation result of measuring the luminance of the backlight unit of the present invention, and FIG. 8B is a graph measuring the amount of light emitted from the backlight unit of the present invention for each position.

Here, the horizontal axis of FIG. 8B represents a position angle at which light is emitted based on 0, which is the front of the backlight unit (120 of FIG. 5), and the vertical axis represents the amount of light emitted from the backlight unit (120 of FIG. 5), based on 1. It is the result measured.

Referring to FIG. 8A, the backlight unit (120 of FIG. 5) of the exemplary embodiment of the present invention measures high front luminance even when the optical sheet (21 of FIG. 1) is not positioned above the light guide plate 210 of FIG. 7. You can check it.

8B, it can be seen that a large amount of light is emitted from the backlight unit 120 of FIG. 5 in the embodiment of the present invention.

That is, as shown in FIGS. 2A and 2B, the light emitted from the existing light guide plate 23 is refracted in the direction opposite to one edge where the LED assembly 29 is located, and thus is emitted from the light guide plate 23. The amount of light to be emitted is a greater amount of light from the side than from the front of the light guide plate 23.

Therefore, one or more optical sheets 21 must be positioned on top of the light guide plate 23, but the backlight unit (120 of FIG. 5) of the present invention has a top and bottom surfaces (FIG. 7 of FIG. 7). A diffusion layer (213 in FIG. 7) and an intaglio prism pattern (215 in FIG. 7) are formed in 211c and 211d in FIG. 7, and the light guide plate (221 in FIG. 7) is formed on the upper surface (221 in FIG. 7) of the reflecting plate (220 in FIG. The light guide plate (Fig. 7) is formed by forming an embossed prism acid pattern (215 in Fig. 7) corresponding to the intaglio prism mountain pattern (215 in Fig. 7) formed on the lower surface (2101 in Fig. 7). Even though the plurality of optical sheets (21 of FIG. 1) are not disposed on the upper part of 210, the light incident on the light guide plate (210 of FIG. 7) is uniformly processed into a high-quality surface light source, thereby providing a uniform surface light source with high luminance. It may be provided to the liquid crystal panel (110 in FIG. 7).

As a result, the configuration of the optical sheet (21 of FIG. 1) on the light guide plate 210 of FIG. 7 can be omitted, and light loss can be prevented from being generated by the optical sheet (21 of FIG. The amount of light may be provided to the liquid crystal panel 110 (see FIG. 7).

In addition, since the components of the backlight unit (120 of FIG. 7) are large, the light weight and thinness of the liquid crystal display device are inhibited or the working process time is increased in the modularization process of the liquid crystal display device. It is possible to provide a light weight and thin liquid crystal display device, and to reduce the working time, thereby improving the efficiency of the process.

The present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention.

120: backlight unit
129: LED assembly (129a: LED, 129b: PCB)
210: light guide plate 211a: light incident surface, 211b: incoming light incident surface, 211c: upper surface, 211d: lower surface
213: diffusion layer
215: Engraved prism mountain pattern (215a, 215b: first and second inclined surfaces)
220: reflector plate (221: upper surface)
225: embossed prism pattern (225a, 225b: third and fourth inclined surfaces)

Claims (11)

A liquid crystal panel;
A light guide plate positioned below the liquid crystal panel, having a diffusion layer formed on an upper surface corresponding to the liquid crystal panel, and a negative prism acid pattern formed on a lower surface of the liquid crystal panel;
A reflector plate disposed below the light guide plate and having an embossed prism pattern formed on an upper surface of the light guide plate;
LED assembly arranged along the light incident surface of the light guide plate
The engraved prism acid pattern may include an angle of forming the refracted light emitted from the lower portion of the light guide plate with a normal line perpendicular to the light guide plate. The embossed prism acid pattern may include the embossed prism acid pattern. The angle formed by the reflected light reflected by the normal and the normal line is reduced,
The engraved prism pattern has a band shape in which peaks and valleys are repeated along the length direction of the LED assembly, and the other inclined side of the first inclined surface facing one direction in which the LED assembly is located is opposite to the one direction. The second inclined surface of the long side facing in the direction,
The embossed prismatic pattern has a band shape in which peaks and valleys are repeated along the longitudinal direction of the LED assembly, and the other side of the third inclined surface facing the one direction in which the LED assembly is located is opposite to the one direction. The fourth inclined surface of the short side facing in the direction,
The third inclined surface has an angle θ3 of the upper surface of the reflector plate θ3 = 1/2 (θ1-θ4) (θ1 is an angle formed by the lower surface of the light guide plate and the first inclined surface, and θ4 is the first inclined surface). And an angle formed by a perpendicular normal and light refracted by the first inclined plane.
delete The method of claim 1,
The first inclined surface is an angle formed with the lower surface of the light guide plate is greater than the total reflection critical angle inside the light guide plate and less than 90 degrees.
The method of claim 3, wherein
And the second inclined surface has an angle of 1 to 3 degrees to the lower surface of the light guide plate.
The method of claim 3, wherein
The engraved prism acid pattern has a height of 5 to 10 μm.
delete delete The method of claim 1,
The embossed prism acid pattern has a height of 10 to 40 μm.
The method of claim 1,
The embossed prism acid pattern is 2 to 4 times larger in size than the intaglio prism pattern.
The method of claim 1,
The diffusion layer includes a light diffusion component including a bead or a fine pattern formed therein.
The method of claim 1,
And a top cover covering the guide panel surrounding the edge of the liquid crystal panel and a cover bottom formed in close contact with the guide panel, and a top cover bordering the edge of the liquid crystal panel and assembled to the guide panel and the cover bottom.
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CN106502000A (en) * 2016-12-02 2017-03-15 武汉华星光电技术有限公司 Backlight module and display floater

Citations (2)

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Publication number Priority date Publication date Assignee Title
JP2002109932A (en) * 2000-10-03 2002-04-12 Enplas Corp Flat light source device and image display device
JP2010146771A (en) * 2008-12-16 2010-07-01 Kuraray Co Ltd Light guide plate, and manufacturing method of light guide plate

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Publication number Priority date Publication date Assignee Title
TW574509B (en) * 2001-02-14 2004-02-01 Yuka Denshi Co Ltd Light guide body, light reflective sheet and surface light source device and liquid crystal device using the light reflective sheet, and the manufacturing method of light reflective sheet

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002109932A (en) * 2000-10-03 2002-04-12 Enplas Corp Flat light source device and image display device
JP2010146771A (en) * 2008-12-16 2010-07-01 Kuraray Co Ltd Light guide plate, and manufacturing method of light guide plate

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