KR100732983B1 - LCD and manufacturing method for light guiding plate used for LCD - Google Patents

Abstract

The present invention relates to a liquid crystal display device and a method of manufacturing a light guide plate employed therein, and more particularly, to remove a reflective sheet disposed on a lower surface of a light guide plate for guiding light of a lamp among components constituting a backlight assembly constituting the liquid crystal display device. The present invention relates to a liquid crystal display device in which a light reflecting film integral with the light guide plate is formed on side and bottom surfaces of the light guide plate which are not in contact with the lamp reflection plate by vacuum deposition such as sputtering, and a method of manufacturing the light guide plate employed therein.

According to the present invention, even when heat is continuously generated from a lamp in the backlight assembly, the light reflecting film formed by vacuum deposition on the light guide plate is not thermally expanded, so that the reflecting sheet does not occur and the brightness of the backlight assembly is improved. To provide a uniform surface light source.

In addition, the manufacturing cost and manufacturing cost of the backlight assembly can be reduced.

Backlight Assembly, Lamp Reflector, Deposition

Description

LCD and manufacturing method for light guiding plate used for LCD

1 is an exploded perspective view showing a liquid crystal display device according to the present invention.

2 is a partial cross-sectional view of a light guide plate according to the present invention.

3 is a partial cross-sectional view of a light guide plate of another embodiment according to the present invention.

4 is a flowchart illustrating a method of manufacturing a light guide plate according to the present invention.

The present invention relates to a liquid crystal display device and a method of manufacturing a light guide plate employed therein, and more particularly, a light guide plate for inducing and diverting light emitted from a lamp in a vertical direction in a backlight assembly of a liquid crystal display device to be in contact with a lamp reflection plate. A liquid crystal display device having a light reflection film formed by a deposition method such as sputtering on the side surfaces and a lower surface of which is not formed so that the reflection sheet does not move due to thermal expansion, thereby reducing luminance and extending life, and a method of manufacturing a light guide plate employed therein. It is about.

As is generally known, one of the display devices, cathode ray tube (CRT) has been mainly used in monitors such as televisions, measuring instruments and information terminal devices, but due to the large weight or size of the CRT itself The demand for miniaturization and weight reduction of electronic products could not be met.

In order to replace the CRT, the advantages of small size and light weight, and a liquid crystal display (hereinafter referred to as 'LCD') displayed by digital control have been actively developed, and in recent years, the role as a flat panel display device has been sufficiently developed. Beyond workable, it is widely used in various fields, and the demand is gradually increasing.

This LCD can be miniaturized because it does not emit light from itself unlike the case of the CRT, and the backlight assembly is configured to supply the light necessary for forming the LCD screen.

In the configuration of the backlight assembly, the lamp generating light, the lamp reflector reflecting the light generated by receiving the lamp toward the light guide plate, and the light emitted from the lamp and the light reflected from the lamp reflector are directed in the vertical direction. A light guide plate for converting the light guide plate, a reflective sheet disposed on the bottom surface of the light guide plate to reflect the light passing through the light without being reflected by the diffused dots of the light guide plate, a polarizing sheet disposed above the light guide plate to change the light into light in the front direction, and a viewing angle It consists of a sheet consisting of a diffusion sheet for converting this widened light into a light having a narrow viewing angle, and a sheet of protection sheet that protects between the diffusion sheet and the liquid crystal panel. The display unit disposed is protected by the top chassis, and the top chassis and the mold frame are in between. It is combined while receiving a byte assembly and the display unit.                         

There are two types of backlight assembly having a structure as described above, silk type and V-CUT type, depending on the structure of the light guide plate.

In the silk type, a plurality of diffused dots are formed in a matrix form on the lower surface of the light guide plate made of acrylic material, which is close to the fluorescent lamp to form a uniform surface light source by appropriately controlling the light guide action and the light diffusion action of the acrylic. The spacing between the silver diffusion dots is wide, and the spacing between the diffusion dots is narrow far away from the fluorescent lamp.

In the silk light guide plate, a reflective sheet made of polyethylene terephthalate (PET) material is disposed below the light guide plate, and the reflection of the PET material is also applied to the side surface of the light guide plate (excluding the light incident surface). The sheet is attached to inject light passing through the diffused dots back into the light guide plate, and the heat generated from the backlight assembly causes the thermal expansion of the PET sheet to thermally expand, thereby expanding the portion of the reflective sheet in a limited space in the mold frame. There is a lack of space to be located, which causes the folds to be lumped, and this phenomenon is called a dent of the reflective sheet.

In addition, unlike the silk type, the light guide plate of the V-CUT type has a plurality of V-shaped grooves formed on the lower surface of the light guide plate instead of being silk printed, and the V-shaped grooves serve as diffusion dots in the silk light guide plate. Do it.

The light guide plate of the V-CUT type also has a reflective sheet disposed on the lower surface thereof, but like the silk printing type, thermal expansion of the reflective sheet occurs for the heat generated from the backlight assembly, causing the reflective sheet to morph.

When the reflective sheet undergoes thermal expansion and hum occurs, non-uniform reflection of light occurs, resulting in a decrease in brightness, photo spots on the surface of the liquid crystal panel, and deterioration of light uniformity, causing quality problems. Addition of airborne causes additional airborne and cost increase.

An object of the present invention is to improve the structure and manufacturing method of the light guide plate constituting the backlight assembly of the liquid crystal display device and the reflective sheet disposed on the bottom of the light guide plate to block the phenomena of the reflective sheet by the light and heat continuously emitted from the lamp It is to prevent the degradation of the brightness of the backlight assembly, and to provide a uniform surface light source.

Other objects of the present invention will be described in more detail in the configuration and operation described below.

The liquid crystal display according to the present invention comprises a display unit, a backlight assembly, a mold frame, and a top chassis.

The display unit includes a liquid crystal panel formed by injecting liquid crystal between a color filter substrate and a thin film transistor (TFT) substrate, a printed circuit board spaced apart from a predetermined side surface of the liquid crystal panel, and a liquid crystal panel. And a tape carrier package connected between the two members between the printed circuit board and the printed circuit board.

The backlight assembly includes a lamp, a semi-circular lamp reflector surrounding the lamp in a longitudinal direction, a light guide plate disposed on a side of the lamp reflector, and a plurality of sheets disposed on the light guide plate, and the mold frame includes a backlight assembly. An accommodating space is formed, and the top chassis is mounted on an upper portion of the panel assembly and combined with the mold frame containing the backlight assembly.

At this time, the light guide plate is characterized in that the light reflecting film is formed by vacuum deposition to reflect the light inside the light guide plate to the upper side.

The light guide plate is further formed on side surfaces of the light guide plate that do not face the lamp reflection plate to prevent light from leaking to the side of the light guide plate.

In addition, the method of manufacturing a light guide plate employed in the liquid crystal display according to the present invention includes a method in which a light reflection film is formed on the lower surface or the lower surface of the light guide plate and the side surfaces of the light guide plate not facing the lamp reflector by vacuum deposition. It is done.

Hereinafter, with reference to the drawings will be described in more detail.

1 and 2, the LCD 200 according to the present invention includes a display unit 20 and a backlight assembly 90 disposed under the display unit 20 to transmit light to the display unit 20. And a mold frame 70 in which an accommodation space for accommodating the backlight assembly 90 is formed, and a top chassis 10 mounted on an upper portion of the display unit 20 and coupled to the mold frame 70.

Specifically, the display unit 20 includes a liquid crystal panel 21 in which liquid crystal is injected between a color filter substrate and a TFT substrate, a printed circuit board 23 spaced apart from a predetermined side of the liquid crystal panel 21, and It consists of a plurality of tape carrier packages 25.                     

A plurality of liquid crystal capacitors (not shown) are formed on the TFT substrate of the liquid crystal panel 21 in the form of a matrix, and a corresponding TFT array is formed on each liquid crystal capacitor, and the gate and source electrodes of the TFT element are formed in one row or the like. It is configured to share a power line of heat.

In order to connect the printed circuit board 23 generating the control signal for driving the TFT array with the liquid crystal panel 21, a plurality of tape carrier packages 25 are disposed between the printed circuit board 23 and the liquid crystal panel 21. In physically and electrically connected.

The backlight assembly 90 disposed below the display unit 20 to provide light includes a lamp 55, a lamp reflector 50, and a quadrangle disposed horizontally on an open side of the lamp reflector 50. The light guide plate 40 which is a flat plate of a phase, and the sheet | seats 37 arrange | positioned and laminated | stacked on the light guide plate 40 are comprised.

 The lamp reflector 50 is a semicircular shape that encloses the lamp 55 in a longitudinal direction, and a side opposite to the light guide plate 40 with respect to the lamp 10 surrounds the lamp 55 largely, and the semicircle of the lamp reflector 50 is The upper and lower extensions extend a predetermined length in the same horizontal direction as the light guide plate 40 to guide the light of the lamp 55 to the light guide plate 40.

The light guide plate 40, which is a feature of the present invention, is arranged horizontally on the open side of the lamp reflector 50 described above as a flat rectangular flat plate, as shown in the partial cross-sectional view of FIG. Is used, and the diffused dots (not shown) which are silk-printed in a matrix shape on the lower surface thereof have a larger dot size as the distance from the lamp reflector 50 increases, so that the distance between the dots is narrower, and the lamp reflector 50 The distance between the dots is formed because the dot size of each look is small.

The light incident surface 45 adjacent to the lamp reflector 50 by the light guide plate 40 is a surface that guides light into the light guide plate 40, and is in contact with the sheets 37 stacked on the light guide plate 40. The light surface 47 is a surface for transmitting the light guided into the light guide plate 40 to the sheets 37.

In this case, the light guide plate 40 is formed with a light reflection film 160 by vacuum deposition so that light applied from the lamp reflector 50 can be reflected to the light exit surface 47 without passing through the light guide plate 40.

Specifically, the light reflection film 160 may be formed on all surfaces of the light guide plate except for the light incident surface 45 and the light exit surface 47, and the light guided to the light guide plate 40 may be formed on the side surfaces other than the light incident surface 45. The light reflecting film 160 is formed to reflect the leaking to the outside of the light guide plate 40 into the light guide plate 40, and the lower surface opposite to the light exiting surface 47 is guided into the light guide plate 40. The light reflection film 160 is formed to reflect the light toward the light exit surface 47.

For example, aluminum is used to form the light reflecting film 160. The light reflecting film 160 is a material having excellent light reflectivity and adhesion by vapor deposition and a property of low thermal expansion, and the light reflecting film 160. The thickness of H should be formed to reflect light at least, and become thicker or thinner in proportion to the time of processing in the vacuum chamber (not shown) in which the deposition process is performed.                     

In addition, in order to improve the light reflectance of the light reflecting film 160, it is also possible to form a multilayer film of low refractive index SiO2 and high refractive index TiO2 on the light reflecting film 160 to form a visible light transmitting infrared reflecting film (not shown). .

 In the sheet 37, a diffusion sheet 31, a polarizing sheet 33, and a protective sheet 35 are sequentially stacked on the light guide plate 40.

The liquid crystal display 200 according to the present invention having the configuration as described above has the following functions.

First, when AC power is applied to the lamp 55 in an inverter circuit (not shown), the lamp 55 emits light by plasma discharge, and the emitted light is reflected by the inner side surface of the lamp reflector 50 so that the light guide plate ( 40).

The light guide plate 40 converts the light applied from the lamp 55 and the lamp reflection plate 50 in the vertical direction to inject a surface light source into the sheet 37, and includes a light reflection film formed under the light guide plate 40. 160 reflects light passing through the lower part of the light guide plate 40 and converts the light into vertical light, and the polarizing sheet 35 and the diffusion sheet 33 of the sheet type 37 convert the incident light into the front light. The front brightness is improved by converting into light, and the brightness is further improved by converting into light having a narrow viewing angle.

At this time, the heat and light continuously generated from the lamp 55 of the backlight assembly 90 is also applied to the light reflection film 160 formed on the light guide plate 40, but the aluminum used as the light reflection film 160 by vapor deposition is the light guide plate ( 40) Excellent adhesion to the light guide plate, and has a structure integral with the light guide plate by evaporation, so the degree of thermal expansion is small, the sheet does not occur, the uniform reflection of light disposed on the light guide plate 40 The uniform surface light source is provided to the diffusion sheet 33.

In addition, a protective sheet 31 passes light between the diffusion sheet 33 and the liquid crystal panel 20 and physically protects the diffusion sheet 33 on the upper portion of the diffusion sheet 33.

Each of the liquid crystal pixels (not shown) formed in the liquid crystal panel 20 functions as an optical shutter that blocks and passes light applied as described above, and is disposed on the side surface of the liquid crystal panel 20. The drive IC (not shown) formed on the VE is converted into a gate control signal and a source data signal by applying a signal applied from the timing controller (not shown) and applied to each liquid crystal pixel (not shown). Determination of blocking is performed, and the entire liquid crystal pixels block or pass light, respectively, to form the entire screen.

As described above, the light reflecting layer 160 formed on the light incident surface 45 and the light exiting surface 47 of the light guide plate has a backlight assembly 90 by removing the reflective sheet, which has been additionally inserted in order to perform light reflection. By simplifying the configuration, since no phenomenon occurs in the heat generated by the backlight assembly 90, a uniform surface light source is provided to the liquid crystal display device 200.

In addition, since the dent of the sheet does not occur, it is not necessary to replace the backlight assembly 90, thereby extending the life of the backlight assembly 90.

In addition, when the printed circuit board 23 bent under the liquid crystal panel 20 and accommodated in the mold frame 70 is in contact with the light reflecting layer 160 made of metal, the light reflecting layer does not need to be separately formed. A ground path through 160 is formed.

3 is another embodiment according to the present invention, wherein the light guide plate is a V-CUT type.

The light guide plate 150 of the V-CUT type has a V shape on the bottom surface of the light guide plate 150, and a plurality of grooves 155 are formed in a horizontal direction with the lamp 55, and the light generated from the lamp 55 is V shaped. A plurality of grooves 155 formed in a V shape serve as a diffusion dot 145 of the silk light guide plate 40 of FIG. 2.

In the light guide plate 150 of the V-CUT type, like the silk light guide plate 40, the light passes through the light guide plate 150 without being reflected from the V-shaped groove 155, and the light is vertically directed. Reflecting is the light reflecting film 170 formed on the lower surface of the light guide plate 150 by vacuum deposition.

After the light is applied in the vertical direction through the light guide plate 150, the subsequent operation is performed by the same process as in the embodiment of Figure 2, the light guide plate 150 of the V-CUT type back light reflecting film 170 The thermal expansion of the lamp 55 does not cause thermal expansion due to thermal expansion, and provides a uniform surface light source to the display unit 20.

As a method of forming the light reflection film 170 as described above, for example, a deposition process by sputtering is used as shown in FIG. 7.

First, the light guide plates 40 and 150 are connected to a cathode in a vacuum chamber (not shown) to be loaded. (S10)

An anode in the vacuum chamber (not shown) is connected to and loaded with a target of a predetermined metal material to be the light reflecting films 160 and 170, and then grounded (S30).                     

The air in the vacuum chamber (not shown) is exhausted to a predetermined pressure to form a vacuum in the vacuum chamber (S50).

A predetermined amount of gas for the discharge catalyst is injected into the vacuum chamber (S70).

~ 10

Pa가 바람직하며, 방전 촉매용 가스로는 바람직하게 Ar(아르곤)가스가 이용될 수 있다.The predetermined pressure of the vacuum is 10

To 10

Pa is preferable, and Ar (argon) gas may be preferably used as the gas for the discharge catalyst.

Plasma discharge is started when a high voltage is applied to the cathode in the vacuum chamber (not shown). (S90)

The cations of the gas for the discharge catalyst are accelerated by the electrical energy to hit the target, and the atoms separated by the impact are deposited on the light guide plates 40 and 150 connected to the cathode to form the light reflecting films 160 and 170. It is formed. (S110)

The light guide plates 40 and 150 on which the light reflection films 160 and 170 are formed are unloaded in a vacuum chamber (not shown).

By using the vacuum deposition method as described above, the light guide plate of various forms, which could not be realized by a material problem in which the reflective sheet attached to the bottom of the light guide plate cannot be bent at various angles in the prior art, is realized in the implementation of the light reflection film by vacuum deposition. It can be implemented accordingly.

In addition, various methods may be used for the vacuum deposition method used to form the light reflection film on the light guide plate, and typically, deposition by sputtering may be used, and a melting point of the light guide plate on which the thin film by vacuum deposition is formed may be used. In consideration of this, a low temperature heating deposition method may be preferably used.                     

As described in detail above, the present invention has been described in detail with respect to preferred embodiments, but those skilled in the art to which the present invention pertains, various embodiments of the present invention without departing from the spirit and scope of the present invention It will be appreciated that the present invention may be modified or modified as described above.

As described above, according to the present invention, even in the light and heat continuously emitted from the lamp, the light reflecting film does not occur in the reflective sheet, thereby preventing a decrease in reflectance, and providing a uniform surface light source to provide a liquid crystal display device. By maintaining the brightness of the uniformity has the effect of extending the life of the backlight assembly.

In addition, since the light reflection film is formed on the light guide plate instead of the reflective sheet, the manufacturing process is shortened and the manufacturing cost is reduced.

In addition, when the printed circuit board is configured to be in contact with the metal light reflection film, the ground path through the light reflection film is formed without the need for a separate ground line, thereby simplifying the configuration and ensuring the reliability of the leakage current.

Claims (10)

A lamp reflector roundly extending in a longitudinal direction in an open state and reflecting light emitted from the lamp toward an open side; A light guide plate disposed in close contact with an open side of the lamp reflector and configured to guide light applied through a light incident side adjacent to the open side to the front; Sheets stacked on the front surface of the light guide plate and configured to polarize and diffuse light applied from the front surface of the light guide plate and transmit the light to the front surface; It is disposed on the front of the sheet comprises a display unit for forming a screen by using the light transmitted from the sheet, On the lower surface of the light guide plate and the side not facing the lamp reflection plate, a visible light transmitting infrared reflecting film formed of a metal light reflecting film formed by vacuum deposition and a multilayer film of high refractive index TiO 2 and low refractive index SiO 2 is formed. Liquid crystal display device. delete The liquid crystal display device according to claim 1, wherein the light reflecting film is made of aluminum. delete delete delete delete delete delete delete

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