KR20120026691A - Liquid crystal display device - Google Patents

Abstract

PURPOSE: A liquid crystal display device is provided to guide light emitted from an LED through a reflection pattern and a reflection plate, thereby realizing a surface light source of high brightness. CONSTITUTION: An LED assembly(129) comprises a plurality of LEDs and a PCB on which a plurality of LEDs are mounted. The thickness of a light guide plate(125) gradually decreases. A diffusing plate(123) is located on the top of the light guide plate. A liquid crystal panel(110) is placed on the diffusing plate. The farther a cover bottom(150) gets from the LED assembly, the closer the cover bottom gets to the diffusing plate.

Description

[0001] Liquid crystal display device [0002]

The present invention relates to a liquid crystal display device including an edge type backlight unit.

Liquid crystal display devices (LCDs), which are used for TVs and monitors due to their high contrast ratio and are advantageous for displaying moving images, are characterized by optical anisotropy and polarization of liquid crystals. The principle of image implementation by

Such a liquid crystal display is an essential component of a liquid crystal panel bonded through a liquid crystal layer between two side-by-side substrates, and realizes a difference in transmittance by changing an arrangement direction of liquid crystal molecules with an electric field in the liquid crystal panel. do.

However, since the liquid crystal panel does not have its own light emitting element, a separate light source is required in order to display the difference in transmittance as an image. To this end, a backlight including a light source is disposed on the back of the liquid crystal panel.

On the other hand, the general backlight unit is divided into an edge type (edge type) and a direct type (direct type) according to the arrangement of the lamp, the edge type has a structure in which one or a pair of lamps are disposed on one side of the light guide plate, Two or two pairs of lamps have a structure in which both sides of the light guide plate are arranged, and the direct type has a structure in which several lamps are arranged under the optical sheet.

Here, the edge type is easier to manufacture than the direct type, and has the advantage of being lighter in weight and lower power consumption than the direct type.

1 is a cross-sectional view of a liquid crystal display using a general edge type backlight unit.

As illustrated, a general liquid crystal display device includes a liquid crystal panel 10, a backlight unit 20, a support main 30, a cover bottom 50, and a top cover 40.

The liquid crystal panel 10 is a part that plays a key role in image expression and is composed of first and second substrates 12 and 14 bonded to each other with a liquid crystal layer interposed therebetween.

The backlight unit 20 is provided behind the liquid crystal panel 10.

The backlight unit 20 includes an LED assembly 29 arranged along at least one edge length direction of the support main 30, a white or silver reflecting plate 25 seated on the cover bottom 50, and a reflecting plate ( A light guide plate 23 seated on 25 and a plurality of optical sheets 21 interposed thereon.

At this time, the LED assembly 29 is configured on one side of the light guide plate 23, and the plurality of LEDs 29a emitting white light and the LED PCB (printed circuit board: 29b, hereinafter, PCB) is mounted on which the LED 29a is mounted. ).

Accordingly, the light guide plate 23 to which light emitted from the plurality of LEDs 29a is incident enters a wide area of the light guide plate 23 while light incident from the LEDs 29a travels inside the light guide plate 23 by a plurality of total reflections. Spread evenly to provide a surface light source to the liquid crystal panel (10).

The liquid crystal panel 10 and the backlight unit 20 have a top cover 40 surrounding the top edge of the liquid crystal panel 10 and a back surface of the backlight unit 20 in a state where the edges are surrounded by the support main 30 having a rectangular frame shape. Cover cover 50 to cover each is coupled in front and rear are integrated through the support main 30 as a medium.

In addition, reference numerals 19a and 19b denote polarizers attached to the front and rear surfaces of the liquid crystal panel 10 to control the polarization direction of light, respectively.

On the other hand, in the process of the light emitted from the plurality of LED (29a) proceeds inside the light guide plate 23 by a plurality of total reflection, the loss of light occurs.

In addition, in the process in which light is emitted to the liquid crystal panel 10 through the light guide plate 23, when light exits from the light guide plate 23 into the air, reflection, refraction, transmission, etc. are generated at the interface.

Even in this case, light does not transmit 100% of the light guide plate 23, and part of the light is lost.

Therefore, the liquid crystal display device using the edge type backlight unit 20 is easier to manufacture than the direct type, has the advantages of lighter weight and lower power consumption than the direct type, and has low light efficiency.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a liquid crystal display device with improved light efficiency, light weight, low thickness, and low power consumption.

In order to achieve the above object, the present invention is a liquid crystal panel; An LED assembly positioned below the liquid crystal panel and including a plurality of LEDs and a PCB on which the plurality of LEDs are mounted; An optical guide plate which is gradually obliquely reduced in thickness toward the opposite side from the light incident surface corresponding to the LED by the upper surface configured to be inclined away from the LED assembly; A diffusion plate positioned above the optical guide plate; A liquid crystal panel seated on the diffusion plate; The bottom surface is formed with a side space to which the LED assembly is attached and spaced apart from the diffusion plate, the bottom surface close to the LED assembly is located far from the diffusion plate, the further away from the LED assembly the diffusion plate And a cover bottom located close to the light emitting device, wherein the light emitted from the plurality of LEDs provides a surface light source through spaced spaces between the diffuser plate and the bottom surface.

In this case, the bottom surface includes a first surface parallel to the diffusion plate and a second surface having an inclination, and the light guide plate is positioned on the first surface.

The optical guide plate adjusts the directing angle of the light emitted from the plurality of LEDs, and the optical guide plate narrows the directing angle of the light emitted from the LED, thereby improving the straightness of the light.

At this time, the cross section of the optical guide plate is an isosceles triangle or quadrangular shape, and the width of the lower surface from the light incident surface to the opposite surface of the optical guide plate is 1/2 to 1 of the width of the bottom surface of the cover bottom. / 3.

Here, the optical guide plate is made of a plastic material such as polymethylmethacrylate (PMMA), which is an acrylic transparent resin, or a polycarbonate (PC) -based resin, and a reflective pattern is formed on the rear surface of the diffusion plate. The reflective pattern is formed at a higher density per unit area as it is closer to the LED assembly, and is formed at a lower density per unit area as it is farther from the LED assembly.

In addition, a reflecting plate is seated on the bottom surface of the cover bottom.

As described above, according to the present invention, the light guide plate is provided so that the light incident surface is positioned in front of the light emitted from the LED, and the reflective pattern formed on the rear surface of the diffuser plate and the reflecting plate seated on the horizontal surface of the cover bottom. By guiding the light emitted from the LED, there is an effect that can be implemented as a surface light source of high brightness.

Through this, when the surface light source implemented from the conventional light guide plate goes out into the air, there is an effect that can solve the problem that some light is lost at the interface.

As a result, the process can be easily simplified and reassembled, and the process cost of the liquid crystal display can also be reduced.

1 is a cross-sectional view of a liquid crystal display device using a general LED as a light source.
2 is an exploded perspective view schematically illustrating a liquid crystal display according to an exemplary embodiment of the present invention.
FIG. 3A is a schematic cross-sectional view of a modular view of the liquid crystal display of FIG. 2. FIG.
3B is a schematic cross-sectional view of the light path of FIG. 3A.
4a to 4b and the experimental results comparing the appearance of the direction of light changes depending on the presence or absence of the light guide plate.
5a to 5b are experimental results comparing the appearance of the light path according to the presence of the light guide plate and the diffusion pattern on the back of the diffusion plate.

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

2 is an exploded perspective view schematically illustrating a liquid crystal display according to an exemplary embodiment of the present invention.

As shown, the liquid crystal display device includes a liquid crystal panel 110, a backlight unit 120, a support main 130, a cover bottom 150, and a top cover for modularizing the liquid crystal panel 110 and the backlight unit 120. 140.

Looking at each of them in more detail, the liquid crystal panel 110 plays a key role in image expression, and the first substrate 112 and the second substrate 114 bonded to each other with the liquid crystal layer interposed therebetween. Include.

At this time, although not shown in the drawings under the premise of an active matrix method, a plurality of gate lines and data lines intersect each other and a pixel is defined on an inner surface of the first substrate 112, which is commonly referred to as a lower substrate or an array substrate. Thin film transistors (TFTs) are provided at each intersection to correspond one-to-one to the transparent pixel electrodes formed in each pixel.

An inner surface of the second substrate 114, called an upper substrate or a color filter substrate, may correspond to each pixel, for example, a color filter of red (R), green (G), and blue (B) color, and these. A black matrix is provided around each other to cover non-display elements such as gate lines, data lines, and thin film transistors. In addition, a transparent common electrode covering them is provided.

A polarizer (not shown) for selectively transmitting only specific light is attached to the outer surfaces of the first and second substrates 112 and 114, respectively.

Along the at least one edge of the liquid crystal panel 110, the printed circuit board 117 is connected through a connecting member 116 such as a flexible circuit board or a tape carrier package (TCP) to support the modularization process. The side surface of the main 130 or the cover bottom 150 is properly folded to be in close contact.

When the thin film transistor selected for each gate line is turned on by the on / off signal of the gate driver circuit, the liquid crystal panel 110 transmits the signal voltage of the data driver circuit to the corresponding pixel electrode through the data line. The arrangement direction of the liquid crystal molecules is changed by the electric field between the pixel electrode and the common electrode, indicating a difference in transmittance.

In addition, the liquid crystal display according to the present invention is provided with a backlight unit 120 for supplying light from its rear surface such 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, a white or silver reflecting plate 127, an optical guide plate 125 mounted on the reflecting plate 127, and a diffusion plate 123 interposed therebetween. It includes a plurality of optical sheet 121.

The LED assembly 129 is located on one side of the light guide plate 125 so as to face the light incident surface of the light guide plate 125, 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 regular intervals.

At this time, the plurality of LEDs 129a include LED chips (not shown) that emit all of the colors of RGB or emit white, and emit white light toward the light guide plate 125. The plurality of LEDs 129a emit light having the colors of red (R), green (G), and blue (B), respectively, and turn on the plurality of RGB LEDs (129a) at once to generate white light by color mixing. It can also be implemented.

The light guide plate 125 to which the light emitted from the plurality of LEDs 129a is incident serves to adjust the directivity angle of the light emitted from the plurality of LEDs 129a, that is, the light guide plate 125 of the present invention. ) Adjusts the directivity angle of the light emitted from the LED 129a to about 90 to about 100 degrees.

Through this, the light emitted from the LED 129a is improved in the straightness, and is emitted farther.

That is, the light guide plate 125 serves to adjust the directing angle of the light emitted from the plurality of LEDs 129a, so that the light emitted from the plurality of LEDs 129a is emitted in a larger area.

The light guide plate 125 is configured such that a lower surface facing the reflecting plate 127 and an upper surface corresponding to the lower surface are inclined, that is, the light guide plate 125 is inclined away from the LED assembly 129. The upper surface is configured to have a thickness gradually obliquely toward the opposite surface from the light incident surface corresponding to the LED 129a.

Thus, the light guide plate 125 may have an isosceles triangle or a rectangular shape in which the top surface is inclined.

The light guide plate 125 is provided on one side of the reflector plate 127 where the LED assembly 129 is located.

Here, when the reflecting plate 127 has the same size as the bottom surface 151 of the cover bottom 150, which will be described later, the width of the lower surface from the light incident surface to the opposite surface of the light guide plate 125 is the reflecting plate 127 Is formed with a width of 1/2 to 1/3.

This is because the conventional light guide plate (23 of FIG. 1) is formed with the same area or the same area as the reflecting plate (25 of FIG. 1), and has a completely different structure from the structure seated on the reflecting plate (25 of FIG. 1). .

The light guide plate 125 may be formed of a plastic material such as polymethylmethacrylate (PMMA), which is one of transparent materials capable of transmitting light, or polycarbonate (PC). Is produced by.

Here, PMMA is an acrylic resin, which is excellent in transparency, weather resistance and colorability, and induces light diffusion when light is transmitted.

The reflection plate 127 is positioned on the rear surface of the light guide plate 125 and reflects light toward the liquid crystal panel 110 to improve the brightness of the light.

In addition, the diffuser plate 123 allows the light passing through the diffuser plate 123 to have a uniform diffusion effect, and a reflective pattern 123a is formed on the rear surface of the diffuser plate 123.

The reflective pattern 123a formed on the back of the diffusion plate 123 serves to guide the light emitted from the plurality of LEDs 129a.

That is, the reflection pattern 123a of the diffusion plate 123 guides the light emitted from the LED 129a together with the reflection plate 127 seated on the horizontal plane 151 of the cover bottom 150 to be described later. It will play a role to implement the light source. We will discuss this in more detail later.

The plurality of optical sheets 121 interposed on the diffusion plate 123 include a diffusion sheet and at least one light collecting sheet, and diffuses the light emitted from the LED 129a through the light diffusion sheet and the light collecting sheet. Alternatively, the light is collected and a more uniform surface light source is incident on the liquid crystal panel 110.

The liquid crystal panel 110 and the backlight unit 120 are modularized through the top cover 140, the support main 130, and the cover bottom 150. The top cover 140 is the top and side surfaces of the liquid crystal panel 110. A rectangular frame having a cross section bent in a shape of “a” so as to cover an edge thereof is configured to open an entire surface of the top cover 140 to display an image implemented in the liquid crystal panel 110.

In addition, the cover bottom 150, which is the basis for assembling the entire apparatus of the liquid crystal display device, has a rectangular plate shape having an edge portion of which the edge is vertically bent, and has a bottom surface 151 closely attached to the back surface of the backlight unit 120 and an edge thereof. Is made up of the vertically bent side 153.

At this time, the LED assembly 129 is adhesiveness such as a double-sided tape on one side of the cover bottom 150 so that light emitted from the plurality of LEDs 129a faces the other side opposite to the one side of the cover bottom 150. The position is fixed through the material (not shown).

As the reflective plate 127 is seated on the bottom 151 of the cover bottom 150, and the diffusion plate 123 and the plurality of optical sheets 121 are interposed on the side surface 153 of the cover bottom 150. The cover bottom 150 defines a light guide region A for guiding light emitted from the LED assembly 129 through the bottom 151 and the side 153.

That is, the light emitted from the plurality of LEDs 129a fixed to one side of the cover bottom 150 is separated from the reflecting plate 127 formed on the bottom 151 of the cover bottom 150 and the reflecting plate 127 thereof. Through the reflective pattern 123a of the diffusion plate 123 positioned with the interspace therebetween, the light spreads evenly in the light guide region A. FIG.

As a result, it is processed into a high luminance surface light source, thereby providing a uniform surface light source to the liquid crystal panel 110.

In particular, the bottom surface 151 of the cover bottom 150 of the present invention by forming a different distance from the diffuser plate 123 according to the fixed position of the LED assembly 129, to realize a more uniform surface and circle do.

That is, the bottom surface 151 of the cover bottom 150 close to the LED assembly 129 fixed to one side of the cover bottom 150 is located far from the diffusion plate 123, and the further away from the LED assembly 129 Close to the diffusion plate 123.

Therefore, both sides perpendicular to one side to which the LED assembly 129 is attached have a form in which the width increases with distance from the LED assembly 129.

Through this, the light emitted from the plurality of LEDs (129a) is a lot of total internal reflection occurs on the side of the edge portion where the LED assembly 129 of the cover bottom 150 is fixed, through which the other edge portion of the cover bottom 150 Until the light reaches.

That is, the light emitted from the plurality of LEDs 129a is spread out to a larger area of the light guide region A of the cover bottom 150.

In addition, although not clearly shown in the drawings, the diffusion plate 123 and the plurality of light diffusing sheet 121 is to prevent the central sag through the sheet support pin (not shown).

That is, in the backlight unit 120 of the present invention, the light guide plate 125 is positioned between the diffuser plate 123 and the reflecting plate 127, but the light guide plate 125 is located only on one side where the LED assembly 129 is located. Only formed, there is substantially nothing between the reflecting plate 127 and the diffusion plate 123.

Accordingly, it is preferable to prevent sagging of the central portion of the diffusion plate 123 and the plurality of light diffusing sheets 121 through sheet support pins (not shown).

The liquid crystal panel 110 is seated on the plurality of optical sheets 121 seated on the cover bottom 150, and the support main body 130 having a rectangular frame shape covering 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 to modularize the liquid crystal panel 110 and the backlight unit 120.

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

In this case, the backlight unit 120 having the above-described structure is generally called a side light method, and according to the purpose, a plurality of LEDs 129a may be arranged on the PCB 129b. In addition, it is also possible to include a plurality of sets of each of the LED assembly 129 and to interpose corresponding to each other along the side edge portions of the cover bottom 150 facing each other.

As described above, the liquid crystal display of the present invention allows the light emitted from the plurality of LEDs 129a to spread out through the light guide plate 125 to a larger area, and is formed on the rear surface of the diffuser plate 123. The light emitted from the LED 129a is guided through the reflective plate 127 seated on the horizontal surface 151 of the pattern 123a and the cover bottom 150, and is fixed to one side of the cover bottom 150. Light emitted from 129a is realized as a surface light source of high luminance.

That is, the backlight unit 120 of the present invention allows the surface light source implemented through the light guide region A to pass through the diffuser plate 123 and the plurality of optical sheets 121 as it is. When the surface light source embodied in 23 goes out into the air, it is possible to solve the problem that some light is lost at the interface.

In particular, it is possible to provide a liquid crystal display device including the edge type backlight unit 120, which is more lightweight, and can reduce the process cost.

FIG. 3A is a schematic cross-sectional view of the LCD module of FIG. 2.

As shown, the LED assembly 129 consisting of a reflecting plate 127, an optical guide plate 125, a diffusion plate 123, a plurality of optical sheets 121 and a plurality of LEDs (129a) and PCB (129b) The liquid crystal panel 110 including the backlight unit (120 of FIG. 2) and the first and second substrates 112 and 114 includes an edge surrounded by the support main 130, and a bottom surface 151 and a rear surface thereof. The cover bottom 150 formed of the side surface 153 is coupled, and the top cover 140 covering the upper edge and the side surface of the liquid crystal panel 110 is coupled to the support main 130 and the cover bottom 150.

Here, the cover bottom 150 is composed of a bottom surface 151 on which the reflecting plate 127 is seated, and a side surface 153 whose edge is vertically bent upward, and the LED assembly 129 is one of the cover bottom 150. The position is fixed to the side through an adhesive material (not shown) such as a double-sided tape.

The light guide plate 125 is mounted on the reflector plate 127, and the light guide plate 125 corresponds to a light incident surface in a direction in which light is emitted from the LED 129a of the LED assembly 129.

The diffuser plate 123 on which the reflective pattern 123a is formed is mounted on the side surface 153 of the cover bottom 150, and a plurality of light diffusing sheets 121 are mounted on the diffuser plate 123.

That is, the reflecting plate 127 and the diffusion plate 123 seated on the bottom 151 of the cover bottom 150 is positioned with a space between the spaced apart.

Accordingly, the cover bottom 150 defines a light guide region A for guiding light emitted from the plurality of LEDs 129a of the LED assembly 129 through the bottom 151 and the side surface 153.

Accordingly, when light is emitted from the plurality of LEDs 129a, the emitted light is incident into the light guide plate 125 through the light incident surface of the light guide plate 125, and the light incident on the light guide plate 125 is provided. The orientation angle is narrowed by the light guide plate 125.

That is, the directivity angle of the light emitted from the LED 129a is 140 to 150, but the directivity angle is narrowed to 90 to 100 by the light guide plate 125.

As a result, the straightness of the light emitted from the LED 129a is improved.

Therefore, the light emitted from the LED 129a of one edge of the cover bottom 150 is emitted farther toward the other edge facing the one edge as the straightness is improved.

In addition, the light having improved straightness through the light guide plate 125 is totally reflected within the defined light guide area A of the cover bottom 150 several times, and thereby the light guide area A of the cover bottom 150. Spreads evenly).

Through this, the surface light source is realized.

In this case, the bottom surface 151 of the cover bottom 150 forms a different distance from the diffusion plate 123 according to the position of the LED assembly 129, and the diffusion plate 123 corresponding to an area close to the LED assembly 129. ) Is formed on the back of the diffuser plate 123a at a high density per unit area, and is formed on the back of the diffuser plate 123 corresponding to a region away from the LED assembly 129 at a low density.

As a result, a surface light source having more uniform luminance may be realized.

In detail, the most light is emitted from one edge of the cover bottom 150 where the LED assembly 129 is positioned, and thus the luminance is highest.

In addition, some of the light passing through the light guide plate 125 may be emitted vertically to the top of the light guide plate 125 by the light guide plate 125, so that the brightness of one edge portion of the cover bottom is higher. do.

As a result, luminance unevenness of the surface light source provided to the liquid crystal panel 110 is generated. In the present invention, the bottom surface 151 of the cover bottom 150 of one edge portion where the LED assembly 129 is positioned is diffused into the diffuser plate 123. By locating away from the cover plate 150, the reflector plate 127 and the diffuser plate 123 seated on the bottom 151 of the cover bottom 150 are spaced apart from each other.

Through this, the light emitted from the LED 129a is not directly incident to the diffusion plate 123, but is diffused to the light guide region A of the cover bottom 150.

 In addition, by forming the reflective pattern 123a formed on the rear surface of the diffusion plate 123 corresponding to one edge side where the LED assembly 129 of the cover bottom 150 is located, the LED assembly 129 is positioned. What you do is make more total reflection of the edges.

As the total internal reflection occurs a lot, the light is spread more widely in the light guide region A of the cover bottom 150.

Therefore, the surface light source having uniform luminance is realized without being affected by the position of the LED assembly 129.

FIG. 3B is a schematic cross-sectional view of the light path of FIG. 3A.

As shown, when the light is emitted from the LED 129a fixed to one side of the cover bottom 150, the light through the light guide plate 125, the light is the opposite side of the one edge portion to which the LED 129a is attached Spread farther towards the other edge.

Then, the distance between the bottom surface 151 of the cover bottom 150 and the diffusion plate 123 is spaced apart, and the reflective pattern 123a formed on the rear surface of the diffusion plate 123 is formed at a high density per unit area, thereby providing an LED ( On the side of one edge portion to which 129a) is attached, more total internal reflection occurs than on the other edge side thereof.

Therefore, the light totally reflected at one edge portion where the LED 129a is fixed is spread to the other edge portion, and the light is more evenly spread over the entire light guide region A of the cover bottom 150.

4A to 4B and the results of experiments in which the direction of light is changed according to the presence or absence of the light guide plate, and FIGS. 5A to 5B show the presence or absence of the light guide plate and the diffusion pattern on the back surface of the diffuser plate. Experimental results comparing the path changes.

Figure 4a is an experimental result showing the directivity angle of the light emitted from the general LED, Figure 4b is an experimental result showing the directivity angle of the light emitted from the LED passed through the light guide plate.

Figure 5a is a result of simulating the path of light emitted from the LED when the optical guide plate is not provided in the embodiment of the present invention, Figure 5b is a light incident surface in front of the light is emitted from the LED according to an embodiment of the present invention When the light guide plate is provided so that the light guide plate is located, and the reflective pattern is formed at a high density per unit area on the back surface of the diffusion plate corresponding to the near area where the LED is located, it is a result of simulating the traveling path of the light emitted from the LED.

First, comparing FIG. 4A and FIG. 4B, the light emitted from the LED 129a passes through the light guide plate 125 of FIG. 3B, whereby the directivity angle is reduced while being emitted farther.

5A to 5B, when the light guide plate 125 of FIG. 3B is not provided as shown in FIG. 5A, the light emitted from the LED (129a of FIG. 3B) has a large directivity angle, and many lights are LEDs. It can be seen that 129a of FIG. 3B is emitted to one edge side of the fixed cover bottom 150 (FIG. 3B).

Accordingly, the luminance of one edge portion where the LED (129a of FIG. 3B) is located is brighter than that of the other regions. As a result, luminance unevenness of the surface light source provided to the liquid crystal panel 110 of FIG. 3A is generated.

In contrast, referring to FIG. 5B, the light emitted from the LED (129a of FIG. 3B) is applied to the cover bottom (150 of FIG. 3B) where the LED (129a of FIG. 3B) is fixed through the light guide plate 125 (FIG. 3B). It can be seen that far out to the other edge portion opposite to one edge portion.

In this way, the light emitted from the LED (129a in FIG. 3B) is emitted far, thereby spreading evenly over the light guide region (A in FIG. 3B) of the cover bottom (150 in FIG. 3B).

In particular, referring to Figure 5b it can be seen that a lot of total reflection occurs at one edge where the LED (129a of FIG. 3b) is located, it can be seen that a lot of totally reflected light is spread evenly to the other edge of the opposite side.

As described above, the present invention includes a light guide plate (125 in FIG. 3B) so that the light incident surface is located in front of the light emitted from the LED (129a in FIG. 3B), and the back of the diffusion plate (123 in FIG. 3B). Emitted from the LED (129a in FIG. 3B) through the reflection pattern (123 in FIG. 3B) formed on the reflective pattern (123a in FIG. 3B) and the horizontal plane (151 in FIG. 3B) of the cover bottom (150 in FIG. 3B). By guiding the light, the light emitted from the LED (129a of FIG. 3b) fixed to one edge of the cover bottom (150 of FIG. 3b) is realized as a surface light source of high brightness.

Through this, the backlight unit (120 of FIG. 3B) of the present invention passes through the diffuser plate (123 of FIG. 3B) and the plurality of optical sheets (121 of FIG. 3B) as it is through the surface light source implemented through the light guide region (A). By doing so, when the surface light source implemented from the existing light guide plate (23 of FIG. 1) goes out into the air, it is possible to solve the problem that some light is lost at the interface.

In particular, it is possible to provide a liquid crystal display device including an edge type backlight unit (120 of FIG. 3B), which is more lightweight, and can also reduce process costs.

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.

110: liquid crystal panel 112: first substrate, 114: second substrate
119a and 119b: first and second polarizing plates
121: a plurality of optical sheets, 123: diffuser plate (123a: reflection pattern), 125: light guide plate
127: reflector
129: LED assembly (129a: LED, 129b: PCB)
130: support main, 140: top cover
150: cover bottom (151: horizontal plane, 153: edge)

Claims (10)

A liquid crystal panel;
An LED assembly positioned below the liquid crystal panel and including a plurality of LEDs and a PCB on which the plurality of LEDs are mounted;
An optical guide plate which is gradually obliquely reduced in thickness toward the opposite side from the light incident surface corresponding to the LED by the upper surface configured to be inclined away from the LED assembly;
A diffusion plate positioned above the optical guide plate;
A liquid crystal panel seated on the diffusion plate;
The bottom surface is formed with a side space to which the LED assembly is attached and spaced apart from the diffusion plate, the bottom surface close to the LED assembly is located far from the diffusion plate, the further away from the LED assembly the diffusion plate Coverboth located close to
And a light emitted from the plurality of LEDs to implement a surface light source through spaced spaces between the diffuser plate and the bottom surface.
The method of claim 1,
And the bottom surface comprises a first surface parallel to the diffusion plate and a second surface having an inclination.
The method of claim 2,
And a light guide plate on the first surface.
The method of claim 1,
The optical guide plate is a liquid crystal display device for adjusting the directivity angle of the light emitted from the plurality of LED.
The method of claim 4, wherein
The optical guide plate narrows the directivity angle of the light emitted from the LED, thereby improving the straightness of the light.
The method of claim 1,
A cross section of the optical guide plate is an isosceles triangle or square shape.
The method of claim 1,
And a width of the lower surface from the light incident surface to the opposite surface of the light guide plate is 1/2 to 1/3 of the width of the bottom surface of the cover bottom.
The method of claim 1,
The optical guide plate is made of a plastic material such as polymethylmethacrylate (PMMA), which is an acrylic transparent resin, or a polycarbonate (PC) -based resin.
The method of claim 1,
A reflective pattern is formed on a rear surface of the diffusion plate, and the reflective pattern is formed at a higher density per unit area as it is closer to the LED assembly, and is formed at a lower density per unit area as it is farther from the LED assembly.
The method of claim 1,
And a reflective plate mounted on the bottom surface of the cover bottom.

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