KR20140085993A - Liquid Display Apparatus - Google Patents

Abstract

The present invention comprises a liquid crystal panel and a backlight unit placed on the lower part of the liquid crystal panel. The liquid crystal panel and the backlight unit are attached to each other by an adhesive layer. Adhesive layers are formed between respective configuration elements of the backlight unit such as a reflective sheet, a light guide plate, a diffusion plate, an upper prism sheet, and a lower prism sheet to attach the respective configuration elements of the backlight unit by the adhesive layers.

Description

[0001] The present invention relates to a liquid crystal display device,

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

2. Description of the Related Art In general, a liquid crystal display device is a display device which can display a desired image by individually supplying data signals according to image information to pixels arranged in a matrix form and adjusting light transmittance of the pixels.

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

The liquid crystal panel includes a thin film transistor array substrate and a color filter substrate bonded to each other so as to maintain a uniform cell gap, and a liquid crystal layer formed in a cell gap between the array substrate and the color filter substrate. And a liquid crystal layer.

At this time, a common electrode and a pixel electrode are formed on the liquid crystal panel in which the array substrate and the color filter substrate are bonded together 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 is rotated by dielectric anisotropy according to the electric field between the common electrode and the pixel electrode And a character or an image is 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 drawings.

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

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

The liquid crystal panel 10 comprises a color filter substrate, 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 device that can not emit light itself but 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, a backlight unit , 60,70: backlight unit) is required.

The backlight unit includes a structure including a light guide plate 50, an LED assembly 60, a reflective sheet 70, a diffusion sheet 23, and an optical sheet 20 composed of upper and lower prism sheets 21 and 22 An LED assembly 60 for generating light is provided on one side of a light guide plate 50. A reflective sheet 70 is provided on the back surface of the light guide plate 50, Is installed. The light emitted from the LED assembly 60 is incident on the side surface of the light guide plate 50 of transparent material and the reflective sheet 70 disposed on the back surface of the light guide plate 50 is transmitted through the back surface of the light guide plate 50 The light is reflected to the upper surface of the light guide plate, thereby reducing light loss and improving the uniformity. Between the light guide plate 50 and the liquid crystal panel 10, a diffusion sheet 23 for diffusing light and prism sheets 21 and 22 for condensing light are arranged.

The liquid crystal panel 10 and the backlight unit are coupled and supported by a mechanism structure such as the guide panel 80 and the cover bottom 90.

The guide panel 80 has a side edge of the liquid crystal panel 10 and a backlight unit inside the cover panel 90. The cover bottom 90 is coupled to the back surface of the guide panel 80, Insert the unit. The liquid crystal panel 10 is fixed to the guide panel 80 through the light shielding tape 30.

At this time, the guide panel 80, the cover bottom 90, and the light shielding tape 30, which are the edge portions of the liquid crystal display, form a bezel.

Since the bezel is a portion where the image is not displayed, it forms the frame of the screen. Therefore, the liquid crystal display device nowadays attempts to visually enlarge the screen by minimizing the size of the bezel.

Since the guide panel 80 and the cover bottom 90 are disposed in the bezel area which forms the frame of the screen and the backlight unit and the liquid crystal display panel are supported while the guide panel 80 and the cover bottom 90 are disposed, Due to the volume, there are limits to reducing the bezel area and thickness.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is an object of the present invention to reduce a bezel area of a liquid crystal display device, to visually enlarge a screen, and to reduce the thickness thereof, thereby facilitating portability and installation.

In order to achieve the above-mentioned object, the present invention includes a liquid crystal panel and a backlight unit located under the liquid crystal panel. Wherein the liquid crystal panel includes an upper substrate and a lower substrate facing each other with a liquid crystal layer interposed therebetween, an upper polarizer disposed on the upper substrate, and a lower polarizer positioned below the lower substrate, A light guide plate for guiding light from the light guide plate to the liquid crystal panel, a reflective sheet disposed under the light guide plate, an LED assembly inserted in a groove formed in the light guide plate, and an optical sheet disposed on the light guide plate, The liquid crystal panel, the optical sheet, the light guide plate, and the reflective sheet are bonded to each other. Here, the optical sheet includes a diffusion sheet and a prism sheet, and the prism sheet includes an upper prism sheet and a lower prism sheet.

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

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

The LED assembly includes a light emitting device and a printed circuit board that supplies power and signals to the light emitting device. The printed circuit board is formed of FPCB or metal PCB.

When the FPCB is applied to the printed circuit board, a diffusion sheet is disposed on a side surface of the FPCB, a prism sheet is disposed on the FPCB and the diffusion sheet, and the prism sheet covers the entire FPCB and the diffusion sheet have.

When a metal PCB is applied to the printed circuit board, an optical sheet is disposed on a side surface of the metal PCB, a lower polarizer is disposed on the metal PCB and the optical sheet, and the lower polarizer covers the entire surface of the metal PCB and the optical sheet. Respectively.

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 integral 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 composed of an integral optical sheet in which a prism sheet and an optical sheet are integrally formed. The light guide plate may be formed of a diffusion sheet integrated light guide plate integrally formed with the diffusion sheet.

The backlight unit may include a light guide plate having a plurality of grooves formed on a back surface thereof, and a direct-type LED assembly including an LED assembly and an optical sheet inserted in the light guide plate grooves.

On the other hand, an adhesive layer is formed between the liquid crystal panel, the optical sheet, the light guide plate, and the reflective sheet to adhere the respective components, and the adhesive layer is formed to have the same size as each component and has an index of refraction of 1.38 to 1.80 .

According to an embodiment of the present invention, it is possible to reduce the size and thickness of the bezel by joining all components of a liquid crystal display device and deleting components such as a guide panel and a cover bottom.

1 is a schematic exploded perspective view of a conventional liquid crystal display device.
2 is a schematic exploded perspective view according to the present invention.
3 is a sectional view showing various embodiments of the LED assembly and the optical sheet according to the present invention.
4 is a 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 illustrating a direct-type LED assembly according to an exemplary embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Like reference numerals throughout the specification denote substantially identical components.

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, a backlight unit disposed 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.

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

However, in the present invention, the cover bottom and the guide panel are removed, and the liquid crystal panel 100 and the backlight units 200, 600, and 700 are fixed to the adhesive layer (800), and fixed with an adhesive layer (800). When the cover bottom, the guide panel, and the light-shielding tape are removed as described above, a light leakage phenomenon occurs in which light generated in the backlight unit leaks to the side. To prevent this, a black print layer 900 is formed on all sides of the liquid crystal panel and the backlight unit ).

As described above, when the cover bottom and the guide panel, which are the bezel areas of the liquid crystal display, are removed, 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 eliminated.

The backlight unit includes a light guide plate 500 for guiding light from the light source to the liquid crystal panel, a reflective sheet 700 disposed under the light guide plate, an LED assembly 600 inserted in the groove formed in the light guide plate, The term " reflection sheet " refers to a structure including all of the optical sheets 200 disposed on the upper side. The arrangement of the backlight units is such that the reflective sheet 700 is disposed on the most bottom surface, And the LED assembly 600 is inserted into the groove 510 formed on the side of the light guide plate. An optical sheet 200 composed of a diffusion sheet 230 and upper and lower prism sheets 210 and 220 is disposed above the light guide plate.

In 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. The reflective sheet 700 is disposed under the light guide plate, and the light incident on the lower portion of the light guide plate is reentered 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 to uniformize the light distribution emitted upward from the light guide plate and to condense the light in a direction perpendicular to the plane of the liquid crystal panel.

An adhesive layer 800 is formed between the reflective sheet, the light guide plate, and the optical sheet, which are components of the backlight unit, and each component is adhered by an adhesive layer. The 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 the components of the optical sheets are adhered to each other.

The liquid crystal panel 100 includes a top substrate 120 and a bottom substrate 130 facing each other with a liquid crystal layer (not shown) interposed therebetween.

Although not shown, a plurality of gate lines and data lines cross each other on the inner surface of a lower substrate 130 called an array substrate, pixels are defined, and thin film transistors (TFT) are provided for each of the intersections. And are connected in a one-to-one correspondence with the transparent pixel electrodes formed in the respective pixels.

A color filter of red (R), green (G), and blue (B) colors corresponding to each pixel is disposed on the inner surface of the upper substrate 120 called a color filter substrate, A data line, and a black matrix for covering non-display elements such as thin film transistors. When a signal is applied to the gate line to turn on the thin film transistor, a signal is applied to the pixel electrode through the data line. As a result, 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 located below the lower substrate 130.

As described above, the backlight unit is positioned below the liquid crystal panel to supply light, and the liquid crystal molecules of the liquid crystal layer are driven to generate a difference in transmittance generated externally, thereby realizing an image of the liquid crystal display device.

3 is a cross-sectional view of various embodiments of an LED assembly and an 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, the liquid crystal panel 100 are formed basically of the same size, and the adhesive layer 800 is formed between the respective components as described above, and they are adhered and fixed to each other by the adhesive layer.

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 is composed of an LED 610 and a flexible printed circuit board (FPCB) 630 or a printed circuit board (PCB) 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 on the light guide plate.

3 (a), the metal PCB is formed to have a thickness similar to the thickness of the optical sheet 200, and the metal PCB 620 having a shape protruding from the upper side of the light guide plate 500 is formed. The optical sheet is formed to have a length corresponding to the width of the metal PCB. Thus, the metal PCB and the optical sheet are formed without overlapping portions, and the upper surface of the metal PCB 620 and the optical sheet 200 are formed on the same line.

The lower polarizer 140 positioned above the metal PCB and the optical sheet is 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 size of the metal PCB 620 and the optical sheet 200. An adhesive layer 800 is formed on the lower portion of the lower polarizer 140 to be bonded to the upper portion of the metal PCB and the optical sheet. When the lower polarizer, the metal PCB, and the optical sheet are formed as described above, the lower polarizer, the metal PCB, and the optical sheet can be bonded without changing the size and thickness of the adhesive layer.

That is, an optical sheet is disposed on a side surface of the metal PCB, and a lower polarizer is disposed on the metal PCB and the optical sheet, and the lower polarizer covers the entire metal PCB and the optical sheet.

3 (b), the FPCB 630 of the LED assembly 600 is mounted on the side of the FPCB 630 of the LED assembly 600, A diffusion sheet 230 is disposed. The thickness of the FPCB 630 is similar to the thickness of the diffusion sheet 230, and the diffusion sheet is formed to have a length corresponding to the FPCB width. 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 plate 140 disposed on the upper part of 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 the upper and lower prism sheets, the FPCB, and the diffusion sheet can be bonded without changing the thickness.

That is, a diffusion sheet is disposed on a side surface of the FPCB, and a prism sheet is disposed on the FPCB and the diffusion sheet, and the prism sheet covers the entire FPCB and the diffusion sheet.

3C is a perspective view illustrating another embodiment of the FPCB fixing method in which the step 510 is formed in the upper portion of the groove 510 formed in the light guide plate 500 by the thickness and width of the FPCB 630, And the whole is inserted into the grooves 510 and 520 of the light guide plate. The optical sheet 200 having the same size as the size of the light guide plate is adhered to an upper portion of the light guide plate with an adhesive layer. When the entire LED assembly is inserted into the grooves of the light guide plate, there is no portion protruding from the top of the light guide plate, and the size of the optical sheet disposed thereon is not changed, simplifying the manufacturing process and structure.

4 is a 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 can be variously modified.

4 (a) shows an embodiment in which the upper and lower prism sheets among the constituent elements of the optical sheet are not used individually but the prism sheet 240 which is integrally formed is used. When the integral 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.

Fig. 4 (b) shows an embodiment in which the diffusion sheet and the upper and lower prism sheets, which are components of the optical sheet, are integrally formed. If the integrated optical sheet 250 is used as in the present embodiment, the thickness of the liquid crystal display device can be further reduced since the two adhesive layers and the sheet layer can be omitted.

Fig. 4 (c) shows an embodiment using a diffusing sheet-integrated light guide plate 530 in which a diffusion sheet, which is a component of the optical sheet, and a light guide plate are integrally formed. That is, the diffusion sheet function is added to the light guide plate, and the diffusion sheet is omitted. It is possible to realize a liquid crystal display device having a reduced thickness as compared with the basic structure by constituting the integrated light guide plate 530 in which the functions of the optical sheet and the light guide plate are integrated.

The structure of the present invention can also be applied to a direct-type LED backlight. 5, the direct-type LED backlight according to the present embodiment has a structure in which a plurality of grooves 540 are formed on the back surface of the light guide plate 500 and a direct-type LED assembly 640 is inserted into the grooves, Is the same as the existing structure except that the components including the adhesive layer are bonded by the adhesive layer. Also in the direct-type LED backlight, the optical sheet and the light guide plate may be integrally formed as shown in Fig.

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

<Table 1>

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

The refractive index of the adhesive layer between the light guide plate and the diffusion sheet in 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% from the conventional technology and the emission angle is narrowed by 29.3 degrees.

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

When the constituent elements of each liquid crystal display device are bonded by the adhesive layer, a high luminance and a low emission angle which can not be realized by the conventional structure can be realized.

As the adhesive layer, not only acrylic resin but also SVR which is a photo-curable polymer material and OCA which is a transparent adhesive for optical use can be used.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the 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 comprising a liquid crystal panel and a backlight unit disposed under the liquid crystal panel,
Wherein the liquid crystal panel comprises an upper substrate and a lower substrate facing each other with a liquid crystal layer interposed therebetween, an upper polarizer disposed on the upper substrate, and a lower polarizer positioned below the lower substrate,
The backlight unit includes a light guide plate for guiding light from the light source to the liquid crystal panel, a reflective sheet disposed under the light guide plate, an LED assembly inserted in the groove formed in the light guide plate, / RTI &gt;
Wherein the liquid crystal panel, the optical sheet, the light guide plate, and the reflection sheet are bonded to each other.
The method according to claim 1,
And a black print layer for preventing light leakage is formed on the side surfaces of the liquid crystal panel and the backlight unit.
The method according to claim 1,
Wherein the lower polarizer plate has the same size as the lower substrate.
The method according to claim 1,
Wherein the optical sheet includes a diffusion sheet and a prism sheet,
Wherein the prism sheet includes an upper prism sheet and a lower prism sheet.
5. 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 polarizer are formed to have the same size.
3. The method of claim 2,
Wherein 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 according to claim 6,
Wherein the printed circuit board comprises a flexible printed circuit board (FPCB) or a printed circuit board (PCB).
8. The method of claim 7,
A diffusion sheet is disposed on a side surface of the FPCB,
Wherein a prism sheet is disposed on the FPCB and the diffusion sheet, and the prism sheet covers the entire FPCB and the diffusion sheet.
8. The method of claim 7,
An optical sheet is disposed on a side surface of the metal PCB,
Wherein the lower polarizer is positioned on the upper part of the metal PCB and the optical sheet, and the lower polarizer covers the entire metal PCB and the optical sheet.
The method according to claim 1,
Wherein the optical sheet comprises an integral prism sheet in which an upper prism sheet and a lower prism sheet are integrally formed, and a diffusion sheet.
The method according to claim 1,
Wherein the optical sheet comprises an integral optical sheet in which a prism sheet and an optical sheet are integrally formed.
The method according to claim 1,
Wherein the light guide plate is formed of a diffusion sheet integrated light guide plate integrally formed with a diffusion sheet.
The method according to claim 1,
Wherein the backlight unit includes a light guide plate having a plurality of grooves formed on a back surface thereof, an LED assembly inserted into the light guide plate grooves, and an optical sheet.
The method according to claim 1,
An adhesive layer is formed between the liquid crystal panel, the optical sheet, the light guide plate, and the reflective sheet to adhere the respective components to each other,
Wherein the adhesive layer is formed to have the same size as each of the constituent elements, and is made of an acrylic resin having a refractive index of 1.38 to 1.80.

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