KR102068958B1 - Liquid Display Apparatus - Google Patents

Abstract

The present invention comprises a liquid crystal panel and a backlight unit positioned below the liquid crystal panel, wherein the liquid crystal panel and the backlight unit are bonded by an adhesive layer. In addition, a liquid crystal display device having a structure in which an adhesive layer is formed between a reflective sheet, a light guide plate, a diffusion sheet, and upper and lower prism sheets, which are components of each backlight unit, is also bonded to each component of the backlight unit by an adhesive layer.

Description

Liquid crystal display device {Liquid Display Apparatus}

The present invention relates to a bezel and a liquid crystal display device having a reduced thickness.

BACKGROUND ART In general, a liquid crystal display device is a display device in which data signals corresponding to image information are individually supplied to pixels arranged in a matrix form so that a desired image can be displayed by adjusting light transmittance of the pixels.

Accordingly, the liquid crystal display includes a liquid crystal panel in which pixels are arranged in a matrix and a driver for driving the pixels.

The liquid crystal panel is formed in a thin film transistor array substrate, a color filter substrate, and a cell gap between the array substrate and the color filter substrate, which are bonded to face each other to maintain a uniform cell gap. It consists of a liquid crystal layer.

In this case, a common electrode and a pixel electrode are formed in the liquid crystal panel where the array substrate and the color filter substrate are bonded to apply an electric field to the liquid crystal layer. Therefore, when the voltage of the data signal applied to the pixel electrode is controlled while the voltage is applied to the common electrode, the liquid crystal of the liquid crystal layer rotates by dielectric anisotropy according to the electric field between the common electrode and the pixel electrode. Characters or images are displayed by transmitting or blocking light for each pixel. Hereinafter, a general liquid crystal display device will be described in detail with reference to the accompanying drawings.

1 is an exploded perspective view schematically illustrating a structure of a general liquid crystal display.

As shown in the figure, a general liquid crystal display device includes a liquid crystal panel 10 and a backlight unit.

The liquid crystal panel 10 includes a color filter substrate and an array substrate, and a liquid crystal layer formed between the color filter substrate and the array substrate.

Since the liquid crystal display device configured as described above is a light-receiving element that does not emit light by itself and displays an image by controlling the transmittance of light coming from the outside, a separate device for irradiating light to the liquid crystal panel, that is, the backlight units 20 and 50. (60,70: backlight unit) is required.

The backlight unit includes a light guide plate 50, an LED assembly 60, a reflective sheet 70, a diffusion sheet 23, and an optical sheet 20 including upper and lower prism sheets 21 and 22. In detail, the LED assembly 60 for generating light is provided at one side of the light guide plate 50, and the reflective sheet 70 is formed on the rear surface of the light guide plate 50. It is installed. Light emitted from the LED assembly 60 is incident on the side of the light guide plate 50 of a transparent material, and the reflective sheet 70 disposed on the rear surface of the light guide plate 50 passes through the rear surface of the light guide plate 50. By reflecting the light to the upper surface of the light guide plate, it reduces the loss of light and improves the uniformity. The diffusion sheet 23 for diffusing light and the prism sheets 21 and 22 for condensing light are disposed between the light guide plate 50 and the liquid crystal panel 10.

In addition, the liquid crystal panel 10 and the backlight unit are coupled and supported by a mechanical structure such as the guide panel 80 and the cover bottom 90.

The guide panel 80 borders each side end of the liquid crystal panel 10, and a backlight unit is mounted therein, and the cover bottom 90 is coupled to the rear surface of the guide panel 80 so that the guide panel 80 and the backlight are provided. Insert the unit. The liquid crystal panel 10 is fixed to the guide panel 80 through the light shielding tape 30.

In this case, the guide panel 80, the cover bottom 90, and the light blocking tape 30, which are edges of the liquid crystal display, form a bezel.

Since the bezel is a portion where an image is not displayed and forms an edge of a screen, an LCD has recently attempted to make the screen visually large by reducing the size of the bezel to a minimum.

However, since the guide panel 80 and the cover bottom 90 are disposed in the bezel area forming the edge of the screen and support the backlight unit (and the liquid crystal display panel), the guide panel 80 and the cover bottom 90 may be formed. Due to its volume, there is a limit to reducing the bezel area and thickness.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to reduce the bezel area of a liquid crystal display device so that the screen is visually enlarged and the thickness is reduced to facilitate portability and installation.

In order to achieve the above object, the present invention includes a liquid crystal panel and a backlight unit positioned below the liquid crystal panel. The liquid crystal panel includes an upper substrate, a lower substrate, and an upper polarizing plate disposed on the upper substrate, and a lower polarizing plate disposed below the lower substrate, the upper and lower substrates facing each other with the liquid crystal layer interposed therebetween, wherein the backlight unit includes a light source. A light guide plate for guiding light from the liquid crystal panel, a reflective sheet disposed below the light guide plate, an LED assembly inserted into a groove formed in the light guide plate, and an optical sheet disposed above the light guide plate. The liquid crystal panel, the optical sheet, the light guide plate, and the reflective sheet provide a liquid crystal display device bonded to each other. The optical sheet may include a diffusion sheet and a prism sheet, and the prism sheet may include an upper prism sheet and a lower prism sheet.

In addition, a black print layer is formed on side surfaces of the liquid crystal panel and the backlight unit to prevent light leakage.

The lower polarizing plate is formed to have the same size as the lower substrate, and the reflecting sheet, the light guide plate, the diffusion sheet, the prism sheet, the lower substrate, and the lower polarizing plate are formed to have the same size.

On the other hand, the LED assembly is composed of a light emitting device and a printed circuit board for supplying power and signals to the light emitting device, the printed circuit board is composed of FPCB or metal PCB.

When the FPCB is applied to the printed circuit board, the diffusion sheet is located on the side of the FPCB, the prism sheet is located on the upper portion of the FPCB and the diffusion sheet, the prism sheet is formed in a structure covering the entire FPCB and the diffusion sheet have.

In addition, when the metal PCB is applied to the printed circuit board, the optical sheet is located on the side of the metal PCB, the lower polarizing plate is located on the upper portion of the metal PCB and the optical sheet, the lower polarizing plate covers the entire metal PCB and the optical sheet. It is formed.

The optical sheet and the light guide plate used in the present invention may have various configurations. The optical sheet may be composed of an integrated prism sheet and a diffusion sheet in which an upper prism sheet and a lower prism sheet are integrally formed. The optical sheet may be configured as an integrated optical sheet in which the prism sheet and the optical sheet are integrally formed. The light guide plate may be formed as a diffusion sheet integrated light guide plate integrally formed with the diffusion sheet.

The backlight unit may apply a direct type LED assembly including a light guide plate having a plurality of grooves formed on a rear surface thereof, an LED assembly and an optical sheet inserted into the groove of the light guide plate.

Meanwhile, an adhesive layer is formed between the liquid crystal panel, the optical sheet, the light guide plate, and the reflective sheet to bond respective components, and the adhesive layer is formed to the same size as each component and has an refractive index of 1.38 to 1.80 Is made of.

According to the exemplary embodiment of the present invention, all components of the liquid crystal display are bonded to each other, and components such as the guide panel and the cover bottom may be removed to reduce the bezel size and thickness.

1 is a schematic exploded perspective view of a liquid crystal display according to the prior art.
2 is a schematic exploded perspective view according to the present invention.
3 is a cross-sectional view showing various embodiments of the LED assembly and the optical sheet according to the present invention.
4 is a cross-sectional view showing various embodiments of an optical sheet and a light guide plate according to the present invention.
5 is a cross-sectional view of a direct type LED assembly according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Like numbers refer to like elements throughout.

2 is a schematic exploded perspective view of the present invention.

As shown in FIG. 2, the liquid crystal display device of the present invention includes a liquid crystal panel 100 and a backlight unit positioned below the liquid crystal panel, and an adhesive layer 800 formed between the liquid crystal panel and the backlight unit. The liquid crystal panel and the backlight unit are bonded by the adhesive layer.

The black print layer 900 is formed on side surfaces of the liquid crystal panel 100 and the backlight units 200, 600, and 700.

In the prior art, the backlight unit and the liquid crystal panel are fixed by the cover bottom and the guide panel, and side light leakage is prevented. In the present invention, the cover bottom and the guide panel are removed, and the liquid crystal panel 100 and the backlight unit 200, 600, and 700 are bonded to each other. It is fixed to the (800), and fixed to the adhesive layer (800). As such, when the cover bottom, the guide panel and the light shielding tape are deleted, a light leakage phenomenon occurs in which light generated from the backlight unit leaks to the side, and a black print layer 900 is formed on all sides of the liquid crystal panel and the backlight unit to prevent this. ).

As described above, when the cover bottom and the guide panel, which are bezel regions of the liquid crystal display, are deleted, the screen is visually enlarged. When the liquid crystal panel and the backlight unit are adhered to each other, the air gap of the conventional structure is deleted to reduce the thickness.

The backlight unit includes a light guide plate 500 for guiding light from a light source to the liquid crystal panel, a reflective sheet 700 disposed below the light guide plate, an LED assembly 600 inserted into a groove formed in the light guide plate, and the light guide plate. As a term referring to a structure including all of the optical sheets 200 disposed on the upper side, in the arrangement of the backlight unit, the reflective sheet 700 is disposed at the bottom and the light guide plate 500 is disposed on the reflective sheet. The LED assembly 600 is inserted into the groove 510 formed at the light guide plate side. The optical sheet 200 including the diffusion sheet 230 and the upper and lower prism sheets 210 and 220 is disposed on the light guide plate.

Referring to the operation of the backlight unit, light is first incident on the light guide plate 500 from the LED assembly 600. The light incident on the light guide plate is reflected upward by a pattern (not shown) formed on the bottom surface of the light guide plate. In addition, the reflective sheet 700 is positioned under the light guide plate, and the light incident to the bottom of the light guide plate is re-entered into the light guide plate.

The diffusion sheet 230 and the upper and lower prism sheets 210 and 220 are disposed on the light guide plate so that the light distribution emitted from the light guide plate to the top is uniform, and the light is focused in a direction perpendicular to the plane of the liquid crystal panel.

An adhesive layer 800 is formed between each component of the backlight unit, which is a reflective sheet, a light guide plate, and an optical sheet, and each component is bonded by an adhesive layer. An adhesive layer 800 is also formed between the diffusion sheet 230 and the upper and lower prism sheets 210 and 220, which are components of the optical sheet 200, so that each component of the optical sheet is bonded to each other.

In addition, the liquid crystal panel 100 plays a key role in image expression, and includes an upper substrate 120 and a lower substrate 130 that are bonded to each other with a liquid crystal layer (not shown) interposed therebetween.

Although not shown, a plurality of gate lines and data lines intersect each other to define a pixel on an inner surface of the lower substrate 130, which is commonly referred to as an array substrate, and a thin film transistor (TFT) is provided at each crossing point. They are connected one-to-one with the transparent pixel electrodes formed in each pixel.

In addition, the inner surface of the upper substrate 120 called a color filter substrate includes a color filter of red (R), green (G), and blue (B) color corresponding to each pixel, and a gate line covering each of them. And black matrices covering non-display elements such as data lines and thin film transistors. When a signal is applied to the gate wiring and the thin film transistor is turned on, a signal is applied to the pixel electrode through the data wiring. Accordingly, an electric field is formed between the pixel electrode and the common electrode, and the liquid crystal molecules of the liquid crystal layer are driven by the electric field.

An upper polarizer 110 is positioned on the upper substrate 120, and a lower polarizer is positioned below the lower substrate 130.

As described above, the backlight unit is positioned below the liquid crystal panel to supply light, and the difference in transmittance generated by driving the liquid crystal molecules of the liquid crystal layer is expressed to the outside, thereby causing the liquid crystal display to realize an image.

3 is a cross-sectional view according to various embodiments of the LED assembly and the optical sheet of the present invention.

Referring to FIG. 3, the reflective sheet 700, the light guide plate 500, the diffusion sheet 230, the upper prism sheet 210, the lower prism sheet 220, and the liquid crystal panel constituting the liquid crystal display device according to the present invention. The size or the outer dimensions of the components of 100 are basically all the same, and as described above, an adhesive layer 800 is formed between the respective components, and the adhesive layers are bonded and fixed to each other by the adhesive layer.

In addition, the LED assembly 600 includes a light emitting device and a printed circuit board for supplying power and signals to the light emitting device. That is, the LED assembly includes an LED 610 and a flexible printed circuit board (FPCB) 630 or a metal printed circuit board (620) for supplying signals and power to the LEDs. The LED assembly is inserted into the light guide plate groove 510 as described above. In detail, only the LED portion of the LED assembly is inserted into the light guide plate groove, and the FPCB or the metal PCB is positioned above the light guide plate.

Referring to FIG. 3 (a) with respect to the metal PCB 620 having a shape projecting on the light guide plate 500, the metal PCB is formed to be similar to the thickness of the optical sheet 200, and the metal PCB The optical sheet located on the side of the metal PCB is formed by removing the length by the width of the PCB. Therefore, the metal PCB and the optical sheet are formed without overlapping portions, and the upper surfaces of the metal PCB 620 and the optical sheet 200 are formed on the same line.

The metal polarizer 140 and the lower polarizer 140 positioned on the optical sheet are formed to have the same size as the upper and lower substrates of the liquid crystal panel. That is, the lower polarizer is formed to have the same size as the sum of the sizes of the metal PCB 620 and the optical sheet 200. In addition, an adhesive layer 800 is formed below the lower polarizing plate 140 to be bonded to the upper portion of the metal PCB and the optical sheet. As such, when the lower polarizing plate and the metal PCB and the optical sheet are formed, the lower polarizing plate and the metal PCB and the optical sheet can be bonded without changing the size and thickness of the adhesive layer.

That is, the optical sheet is located on the side of the metal PCB, the lower polarizing plate is positioned on the upper portion of the metal PCB and the optical sheet, the lower polarizing plate is formed to cover the entire metal PCB and the optical sheet.

Another embodiment using the FPCB 630 instead of the metal PCB 620 as the LED assembly 600 will be described with reference to FIG. 3 (b). The optical sheet 200 is formed on the FPCB 630 side of the LED assembly 600. ), The diffusion sheet 230 is disposed. In addition, the thickness of the FPCB 630 is formed to be similar to the thickness of the diffusion sheet 230, the diffusion sheet is formed by deleting the length by the width of the FPCB. For this reason, the FPCB and the diffusion sheet are arranged on the same line without overlapping portions. That is, the upper and lower prism sheets 210 and 220 and the lower polarizer 140 disposed on the FPCB and the diffusion sheet are formed to have the same size as that of the backlight unit or the liquid crystal panel 100, and thus the size of the adhesive layer 800. And it is possible to bond the upper and lower prism sheet, FPCB, diffusion sheet without changing the thickness.

That is, the diffusion sheet is located on the side of the FPCB, the prism sheet is located on the upper portion of the FPCB and the diffusion sheet, the prism sheet is formed in a structure covering the entire FPCB and the diffusion sheet.

3 (c) illustrates another embodiment of fixing the FPCB. A step 520 is formed in the upper end of the groove 510 formed in the light guide plate 500 by the thickness and width of the FPCB 630. The whole is inserted into the grooves 510 and 520 of the light guide plate. In addition, the optical sheet 200 having the same size as the size of the light guide plate is bonded to the upper part of the light guide plate with an adhesive layer. As such, when the entire LED assembly is inserted into the light guide plate groove, there is no part protruding to the upper part of the light guide plate, so that the size of the optical sheet disposed thereon is not changed, thereby simplifying the manufacturing process and structure.

4 is a cross-sectional view showing various embodiments of an optical sheet and a light guide plate according to the present invention. Referring to FIG. 4, the optical sheet 200 and the light guide plate 500 used in the present invention may be variously modified.

4A illustrates an embodiment in which the prism sheet 240 is integrally formed without using upper and lower prism sheets individually among the components of the optical sheet. When the integrated prism sheet 240 is used as in the present embodiment, since one adhesive layer and a prism sheet layer can be omitted, the thickness of the liquid crystal display device is reduced compared to the basic configuration.

Figure 4 (b) is an embodiment in which both the diffusion sheet and the upper and lower prism sheet, which is a component of the optical sheet, are integrally formed. When the integrated optical sheet 250 is used as in this embodiment, since the two adhesive layers and the sheet layer can be omitted, the thickness of the liquid crystal display device is further reduced.

FIG. 4 (c) illustrates an embodiment using a diffusion sheet integrated light guide plate 530 in which a diffusion sheet, which is a component of an optical sheet, and a light guide plate are integrally formed. In other words, the diffusion sheet function is added to the light guide plate, and the diffusion sheet is omitted. When the integrated light guide plate 530 integrating the functions of the optical sheet and the light guide plate is configured, a liquid crystal display device having a reduced thickness compared to the basic configuration may be implemented in the same manner as in the other embodiments.

The structure of the present invention can also be applied to a direct type LED backlight. Referring to FIG. 5, the direct type LED backlight according to the present exemplary embodiment has a structure in which a plurality of grooves 540 are formed on a rear surface of the light guide plate 500, and a direct type LED assembly 640 is inserted into the grooves. Except for the component is bonded by the adhesive layer, including the same as the existing structure. In addition, in the direct type LED backlight, the optical sheet and the light guide plate may be integrated as shown in FIG. 4.

Table 1 below shows simulation results of luminance / emission angle according to the refractive index of the adhesive layer in the structure of the liquid crystal display device to which the respective components are bonded.

TABLE 1

In this simulation, the adhesive layer was formed of an acrylic resin having a refractive index of 1.38 to 1.80. The adhesive layer is formed to the same size as each component constituting the liquid crystal display device.

When the refractive index of the adhesive layer between the light guide plate and the diffusion sheet of Table 1 is 1.38 and the refractive index of the adhesive layer between the diffusion sheet and the lower prism sheet is 1.62, the luminance is reduced by 2.2% compared to the prior art, and the emission angle is narrowed by 29.3 degrees.

Then, when the adhesive layer refractive index between the light guide plate and the diffusion sheet of Table 1 is 1.38, and the adhesive layer refractive index between the diffusion sheet and the lower prism sheet is 1.80, the luminance is increased by 54.3% compared to the prior art, and the emission angle is narrowed by 24.5 degrees.

As such, when the components of the liquid crystal display are bonded by the adhesive layer, high luminance and low emission angles that cannot be realized in the conventional structure can be realized.

As the adhesive layer, not only acrylic resin but also SVR, which is a photocurable polymer material, and OCA, which is an optically clear adhesive, can be used.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

10,100: liquid crystal panel 60,600: LED assembly
110: upper polarizer 610: LED
120: upper substrate 620: metal PCB
130: lower substrate 630: FPCB
140: lower polarizer 640: direct type LED assembly
20,200: Optical sheet 70,700: Reflective sheet
21,210: upper prism sheet 80: guide panel
22,220: lower prism sheet 90: cover bottom
23,230: diffusion sheet 800: adhesive layer
50,500 light guide plate 900 black printing layer
510,540: Home
520: step

Claims (14)

A liquid crystal display device comprising a liquid crystal panel and a backlight unit positioned below the liquid crystal panel.
The liquid crystal panel includes an upper substrate, a lower substrate, and an upper polarizing plate disposed on the upper substrate and the lower substrate facing each other with the liquid crystal layer interposed therebetween, and a lower polarizing plate disposed below the lower substrate.
The backlight unit includes a light guide plate for guiding light from a light source to the liquid crystal panel, a reflective sheet disposed below the light guide plate, an LED assembly inserted into a groove formed in the light guide plate, and an optical sheet disposed above the light guide plate. Including;
The liquid crystal panel, the optical sheet, the light guide plate, and the reflective sheet are bonded to each other,
Black printed layers are formed on all sides of the liquid crystal panel and the backlight unit to prevent light leakage.
And an adhesive layer formed on the entire surface between each of the liquid crystal panel, the optical sheet, the light guide plate, and the reflective sheet, and configured to transmit light.
delete The method of claim 1,
The lower polarizer is formed to have the same size as the lower substrate.
The method of claim 1,
The optical sheet includes a diffusion sheet, a prism sheet,
The prism sheet includes an upper prism sheet and a lower prism sheet.
The method of claim 4, wherein
The reflective sheet, the light guide plate, the diffusion sheet, the prism sheet, the lower substrate, and the lower polarizing plate are formed in the same size.
The method of claim 1,
The LED assembly comprises a light emitting device and a printed circuit board for supplying power and signals to the light emitting device.
The method of claim 6,
The printed circuit board includes a flexible printed circuit board (FPCB) or a metal printed circuit board (PCB).
The method of claim 7, wherein
The diffusion sheet is located on the side of the FPCB,
A prism sheet is positioned above the FPCB and the diffusion sheet, and the prism sheet covers the entire FPCB and the diffusion sheet.
The method of claim 7, wherein
The optical sheet is located on the side of the metal PCB,
And a lower polarizer positioned on the metal PCB and the optical sheet so that the lower polarizer covers the entire metal PCB and the optical sheet.
The method of claim 1,
And the optical sheet includes an integrated prism sheet and a diffusion sheet in which an upper prism sheet and a lower prism sheet are integrally formed.
The method of claim 1,
And the optical sheet comprises an integrated optical sheet in which a prism sheet and a diffusion sheet are integrally formed.
The method of claim 1,
And the light guide plate is formed of a diffusion sheet integrated light guide plate integrally formed with the diffusion sheet.
The method of claim 1,
The backlight unit includes a light guide plate having a plurality of grooves formed on a rear surface thereof, an LED assembly and an optical sheet inserted into the groove of the light guide plate.
The method of claim 1,
The area of the adhesive layer formed between the liquid crystal panel and the optical sheet is the same as the area of the liquid crystal panel,
The area of the adhesive layer formed between the optical sheet and the light guide plate is the same as that of the optical sheet,
The area of the adhesive layer formed between the light guide plate and the reflective sheet is equal to the area of the light guide plate,
The adhesive layer is a liquid crystal display device consisting of an acrylic resin having a refractive index of 1.38 to 1.80.

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