KR101981585B1 - Liquid crystal display device - Google Patents

Abstract

The present invention relates to a liquid crystal display device having thermal durability.
A liquid crystal display device according to the present invention is a liquid crystal display device comprising a cover bottom assembly composed of a rectangular plate-shaped base part, a reinforcing part having a shape opened at the center and supporting the base part at the back side of the base part, And an LED housing disposed on a rear surface of the printed circuit board, wherein the reinforcing portion is formed on both edges in a direction perpendicular to the longitudinal direction of the base portion, And a central reinforcing portion disposed on the inner side of the rim reinforcing portion and composed of first and second central reinforcing portions arranged in parallel to the rim reinforcing portion, wherein the base portion includes a first reinforcing portion and a second reinforcing portion, And a plurality of escape grooves formed at positions corresponding to the respective central reinforcing portions.
According to the present invention, it is possible to prevent thermal deformation due to the difference in thermal coefficient between the edge and the center portion where the LED assembly is disposed.

Description

[0001] LIQUID CRYSTAL DISPLAY DEVICE [0002]

The present invention relates to a liquid crystal display, and more particularly, to a liquid crystal display having excellent heat furability.

2. Description of the Related Art In recent years, the display field has rapidly developed in line with the information age. In response to this trend, a flat panel display device (FPD) having a thinness, light weight, LCD, and organic light emitting diode (OLED) display devices have been widely used with excellent performance.

Among these, liquid crystal display devices which are advantageous for moving picture display and have a large contrast ratio are being actively used in notebooks, TVs, monitors, and the like.

Such a liquid crystal display device (LCD) represents an image realization principle by optical anisotropy and polarization of a liquid crystal.

Such a liquid crystal display device has a liquid crystal panel in which a liquid crystal layer is interposed between two substrates arranged side by side, and the direction of arrangement of the liquid crystal molecules is changed by the electric field in the liquid crystal panel, .

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

Such a liquid crystal panel and a backlight unit are integrated and modularized by a top cover located at the front face of the liquid crystal panel, a support main which separates the liquid crystal panel and the backlight unit, and a cover bottom located at the back face of the backlight unit,

As a light source of the backlight unit, a fluorescent lamp such as a cold cathode fluorescent lamp (CCFL) or an external electrode fluorescent lamp (EEFL) has been widely used. Recently, however, Light-emitting diodes (LEDs), which have advantages in terms of power consumption, weight, and brightness, have been replacing fluorescent lamps with lightweight trends.

According to the position of the light source, it can be classified into a direct type and an edge type. In the direct type backlight unit, a light source is disposed below the liquid crystal panel, and light emitted from the light source is directly incident on the liquid crystal panel In the backlight unit of the side-type system, a light guide plate is disposed under the liquid crystal panel, and a light source is disposed on at least one side surface of the light guide plate so that light emitted from the light source is indirectly reflected by the light- .

At this time, the side-type backlight unit is easier to manufacture than a direct-type backlight unit, and has a tendency to be used in many cases because it is thin, light in weight and low in power consumption.

In recent years, the liquid crystal display device including the backlight unit has been used in a wide variety of fields such as a desktop computer monitor and a wall-hung television as well as a portable computer, and a research for enlarging the display area to have a wider display area It is actively proceeding.

At this time, the liquid crystal display device including the side-type backlight unit becomes large in size, and the temperature difference between the edge portion where the light source is positioned and the center portion where the light source is not formed becomes further widened. Such a temperature difference causes the liquid crystal panel and the backlight unit There is a phenomenon that the component to be modulated, particularly the cover bottom on which the backlight unit is mounted, is twisted due to thermal deformation.

This is a phenomenon caused by different thermal expansion between the edge portion of the cover bottom and the central portion. When the cover bottom is severely twisted by the thermal deformation, the top cover is also twisted together and the inner liquid crystal panel is pressed by the top cover, . In addition, internal components are damaged, and in some cases, the liquid crystal display device is often damaged.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to solve the above-mentioned problems and to provide a cover ballum assembly comprising two component elements for improving rigidity and heat dissipation and forming an escape groove for avoiding thermal deformation, And a liquid crystal display device.

It is another object of the present invention to provide a liquid crystal display device in which an escape groove formed in a cover bottom assembly is not exposed.

Another object of the present invention is to provide a liquid crystal display device capable of preventing damage to components due to thermal deformation and preventing light leakage.

According to another aspect of the present invention, there is provided a liquid crystal display device including a base plate having a rectangular plate shape, a cover having a central opening and a reinforcing portion for supporting and supporting the base at the backside of the base, A bottom end assembly; An LED assembly having a plurality of LEDs mounted on a printed circuit board and disposed along a longitudinal direction of the reinforcing portion; And an LED housing disposed on a rear surface of the printed circuit board, wherein the reinforcing portion includes a rim reinforcing portion which rims on both edges in a direction perpendicular to the longitudinal direction of the base portion, and a rim reinforcing portion disposed inside the rim reinforcing portion, And a central reinforcing portion formed of first and second central reinforcing portions arranged in parallel to the first and second central reinforcing portions. The base includes a plurality of escape grooves formed at positions corresponding to the first and second central reinforcing portions.

The LED housing is composed of a vertical part in contact with the back surface of the printed circuit board and a horizontal part perpendicular to the vertical part and covering one side of the plurality of LEDs and a part of the back edge of the base part.

At this time, the horizontal portion of the LED housing is exposed to the outside and is in contact with the atmosphere.

The base portion is seated on an inner surface of the horizontal portion, and the reinforcing portion is partially located on an outer surface of the horizontal portion.

And the plurality of escape grooves are formed in two rows along the direction perpendicular to the longitudinal direction corresponding to each of the first and second central reinforcing portions.

At this time, the length of the escape grooves formed on the outermost side of the plurality of escape grooves is longer than the length of the escape grooves formed on the inner side.

On the other hand, among the rim reinforcing portions, the rim reinforcing portions in the longitudinal direction facing each other are made of aluminum, the remaining rim reinforcing portions are made of an electrolytic galvanized liner (EGI), and the center reinforcing portion is made of aluminum .

According to the liquid crystal display device according to the present invention, it is possible to prevent thermal deformation by forming a plurality of escape grooves in the base portion of the cover bottom assembly for operating as a fluid space for thermal contraction and expansion.

As a result, it is possible to prevent damage to internal components, prevent light leakage due to distortion, and further realize a liquid crystal display device having excellent heat durability.

In addition, by preventing a plurality of escape grooves from being exposed to the outside of the liquid crystal display device, it is possible to prevent dust and foreign matter from being injected and to prevent light leakage through a plurality of escape grooves.

1 is an exploded perspective view illustrating a liquid crystal display device according to a preferred embodiment of the present invention.
FIG. 2A is a cross-sectional view taken along the line A-A of FIG. 1; FIG.
2B is a cross-sectional view taken along the line B-B in FIG.
2C is a sectional view taken along the line C - C in Fig. 1; Fig.
3 is a rear perspective view illustrating a coupling between components of a cover bottom assembly according to a preferred embodiment of the present invention.
4 is a plan view of a base portion of a cover bottom assembly according to a preferred embodiment of the present invention.
5A and 5B are enlarged plan views of the AB region of FIG. 4;

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

FIG. 1 is an exploded perspective view showing a liquid crystal display device according to a preferred embodiment of the present invention, FIG. 2 (a) is a cross-sectional view taken along line A-A in FIG. 1, 3 is a sectional view taken along the line C - C of FIG. 1. FIG. 3 is a rear perspective view illustrating a coupling between components of the cover bottom assembly according to a preferred embodiment of the present invention. FIG. to be.

The liquid crystal display 100 includes a liquid crystal panel 110, a backlight unit 120, a support main body 130 for modulating the liquid crystal panel 110 and the backlight unit 120, 140 and a cover bottom assembly 150.

The liquid crystal panel 110 is a part that plays a key role in image display and is composed of a first substrate 112 and a second substrate 114 which are bonded to each other with a liquid crystal layer interposed therebetween.

Although not shown in the drawings, a plurality of gate lines and data lines cross each other on the inner surface of a first substrate 112, which is usually called a lower substrate or an array substrate, on the premise of an active matrix system, pixels are defined, And a thin film transistor (TFT) is provided and connected in a one-to-one correspondence with the transparent pixel electrode formed in each pixel.

On the inner surface of the second substrate 114 called an upper substrate or a color filter substrate, a color filter of red (R), green (G), and blue (B) And a black matrix covering the non-display elements such as the gate lines, the data lines, and the thin film transistors is provided. A transparent common electrode corresponding to the pixel electrode may be provided on the first substrate 112 or the second substrate 114.

The first and second polarizers 119a and 119b selectively transmit only specific light to the outer surfaces of the first and second substrates 112 and 114, respectively.

A printed circuit board 117 is connected to at least one edge of the liquid crystal panel 110 via a connection member 116 such as a flexible circuit board or a tape carrier package (TCP) To the side of the support main portion 130 or to the back surface of the base portion 151 of the cover bottom assembly 150, as shown in FIG.

When the thin film transistor selected for each gate line is turned on by the on or off signal of the gate driving circuit transmitted through the printed circuit board 117, the liquid crystal panel 110 having the above- The signal voltage is transmitted to the corresponding pixel electrode through the data line, and the alignment direction of the liquid crystal molecules is changed by the electric field between the pixel electrode and the common electrode.

On the rear surface of the liquid crystal panel 110, a backlight unit 120 is provided to supply light so that the difference in transmittance can be displayed as an image.

The backlight unit 120 includes a light source arranged along both edges facing each other, a reflective plate 125, a light guide plate 123 resting on the reflective plate 125, and a plurality of optical sheets 121 ). The cover bottom assembly 150 is disposed on the back surface of the backlight unit 120. The cover bottom assembly 150 includes a base 151 and a rim reinforcement 154 and a center reinforcement 155 And a reinforcing portion 153 provided with a reinforcing portion 153.

Here, the LED 129a is used as a light source, and a plurality of LEDs 129a are spaced apart from each other by a predetermined distance to be mounted on a printed circuit board (PCB) 129b, thereby forming an LED assembly 129.

At this time, the printed circuit board 129b may correspond to a metal core printed circuit board (MCPCB) having a heat dissipating function for dissipating heat generated from the plurality of LEDs 129a.

An LED housing 128 is provided outside the LED assembly 129. The LED housing 128 is made of a metal material having excellent thermal conductivity, for example, aluminum.

The LED housing 128 includes a vertical portion 126 covering the back surface of the printed circuit board 129b and a plurality of LEDs 129a vertically connected to the vertical portion 126 and facing the cover bottom assembly 150 And a horizontal portion 127 surrounding the bottom surface and the back edge of the base portion 151 of the cover bottom assembly 150.

At this time, the printed circuit board 129b of the LED assembly 129 is attached and fixed to the inside of the vertical portion 126 of the LED housing 128 through an adhesive material or adhesive means (for example, a tape) Is faced to the light-incoming portion of the light guide plate 123. The light-

The light emitted from the plurality of LEDs 129a of the LED assembly 129 is incident into the light guide plate 123 through the light incident portion and is indirectly incident on the liquid crystal panel 110 using the refraction and reflection at the light guide plate 123. [ .

2C, only the center reinforcing portion 155 of the reinforcing portion 153 of the cover bottom assembly 150 is partially in contact with the back surface of the horizontal portion 127 of the LED housing 128. As shown in FIG. As the cover bottom assembly 150 is partially contacted only partially in this manner, most of the horizontal portion 127 is exposed to the outside of the liquid crystal display device 100 and comes into contact with the atmosphere.

The heat generated from each of the plurality of LEDs 129a of the LED assembly 129 is transmitted to the horizontal portion 127 through the vertical portion 126 of the LED housing 128 via the printed circuit board 129b And is quickly released to the outside by the horizontal portion 127 exposed to the outside. Since the heat of the high temperature generated from the plurality of LEDs 129a is discharged more rapidly through the LED housing 128, the life of each of the plurality of LEDs 129a can be prolonged, . ≪ / RTI >

On the other hand, the LED housing 128 may have grooves on the inner surface and the outer surface of the horizontal portion 127, respectively. The groove formed in the inner surface of the horizontal portion 127 of the LED housing 128 provides a space for the printed circuit board 129b of the LED assembly 129 to be disposed and can serve as a space for air circulation. 2C, the groove formed on the outer surface of the horizontal portion 127 of the LED housing 128 may serve as a space for the center reinforcement portion 155 to be disposed.

Although the LED housing 128 is shown to correspond to the number of the LED assemblies 129, the present invention is not limited thereto, and both ends of the horizontal portion 127 of each LED housing 128 may be connected to each other, Of the LED housing.

A base portion 151 of the cover bottom assembly 150 is seated inside the horizontal portion 127 of the LED housing 128. An upper portion of the base portion 151 of the cover bottom assembly 150 (Not shown).

The reflection plate 125 reflects light passing through the back surface of the light guide plate 123 in a rectangular plate shape toward the liquid crystal panel 110, thereby improving the brightness of light.

The light guide plate 123 guides light emitted from each of the plurality of LEDs 129a to serve as a high-quality surface light source.

The light guide plate 123 has a rectangular plate shape and may include a pattern of a specific shape on the back surface to supply a uniform surface light source. The pattern may be formed in various shapes such as an elliptical pattern, a polygon pattern, a hologram pattern, and the like in order to guide light incident into the light guide plate 123, Is formed on the lower surface of the light guide plate 123 by a printing method or an injection method.

The light guide plate 123 may be made of polymethyl methacrylate (PMMA) or polymethacrylic styrene (MS) resin in which polymethyl methacrylate (PMMA) and polystyrene (PS) are mixed. have.

The plurality of optical sheets 121 interposed on the light guide unit 123 are formed so as to diffuse or condense the light converted into the surface light source by the light guide plate 123 so that a more uniform surface light source is incident on the liquid crystal panel 110. [ do.

The plurality of optical sheets 121 may include a diffusion sheet for diffusing light, a prism sheet for condensing light, and a protective sheet for protecting the prism sheet and serving as an auxiliary for diffusing light.

The liquid crystal panel 110 and the backlight unit 120 described above are modularized through the top cover 140, the support main body 130, and the cover bottom assembly 150.

The support main body 130 has a rectangular frame shape and is an instrument for separating the liquid crystal panel 110 and the backlight unit 120 from each other.

The support main 130 includes a first portion 132 surrounding the edges of the liquid crystal panel 110 and the backlight unit 120 and a second portion 132 perpendicularly connected to the first portion 132, And a second portion 134 for separating the liquid crystal panel 110 and the backlight unit 120 from each other.

The top cover 140 has a rectangular frame shape bent in a "? &Quot; shape so as to cover a front edge of the liquid crystal panel 110 and a side portion of the support main 130, So that the image to be implemented can be displayed.

The cover bottom assembly 150 which is a core structure of the present invention is a base structure of the entire structure of the liquid crystal display device 100 and includes a base portion 151 for supporting the backlight unit 120 and a base portion 151 And a reinforcing portion 153 for reinforcing the support.

Here, the base portion 151 has a rectangular plate shape and can be made of aluminum for rigidity.

A reflective plate 125, a light guide plate 123, and a plurality of optical sheets 121 are sequentially placed on the front surface of the base unit 151.

Particularly, the base portion 151 is characterized by including a plurality of escape grooves 152 for avoiding deformation due to heat.

At this time, the plurality of escape grooves 152 serve as the first role of releasing the heat transmitted from the opposite edges of the base portion 151 and the first space serving as the heat dissipation preventing portion by providing the space for contraction and expansion due to heat. 2 role. That is, the plurality of escape grooves 152 serve as a discharge space for releasing heat and a flow space for heat shrinkage and expansion.

The plurality of escape grooves 152 are formed in a state of being spaced apart from each other by a predetermined area in a direction perpendicular to the longitudinal direction. The escape grooves 152 are formed in a row at positions corresponding to the central reinforcing portions 155, . This will be described in detail later.

The cover bottom assembly 150 including the base portion 151 is configured such that heat is intensively generated from a light source disposed along the longitudinal direction of both opposite edges of the cover bottom assembly 151 and the heat coefficient between the edge portion where the light source is disposed and the center portion the plurality of escape grooves 152 of the inner base 151 serve as a compensating means for compensating for the difference in thermal coefficient, thereby avoiding thermal deformation. As a result, damage to internal components is prevented, and a reliable liquid crystal display device can be realized.

The reinforcing portion 153 is provided on the rear surface of the base portion 151 to support and reinforce the base portion 151. The reinforcing portion 153 includes a rim reinforcing portion 154 for trimming the edge in the direction perpendicular to the longitudinal direction in which the light source is disposed, And a center reinforcing portion 155.

The rim reinforcing portion 154 is constituted by first and second rim reinforcing portions 154a which rims are opposite to each other in the direction perpendicular to the longitudinal direction of the base portion 151. The first and second rim reinforcing portions 154a, (154a) may be configured in a separate bar shape. The rim reinforcing portion 154 may be formed as first to fourth rim reinforcing portions corresponding to the respective four edges of the base portion 151. Each of the rim reinforcing portions may be formed in a bar shape and separated from each other.

Here, the first and second frame reinforcing portions 154a may have a shape bent in a " b " shape so as to cover a part of the side surface of the backlight unit 120. [

The center reinforcing portion 155 is provided with first and second center reinforcing portions 155a and 155b in the form of bars. The first and second center reinforcing portions 155a and 155b are provided in the first and second frame reinforcing portions 155a and 155b, The first and second frame reinforcement parts 154a and 154b are arranged in parallel with the first and second frame reinforcement parts 154a in a state of being spaced apart from each other by a predetermined distance in the inside of the base part 151a, thereby reinforcing the center part of the base part 151, .

3, the central reinforcing portion 155 is joined at the rear of the base portion 151 at the time of modularization and is located at the back surface of the plurality of escape grooves 152 of the base portion 151. [ This prevents a plurality of escape grooves 152 formed in the base 151 from being exposed to the outside of the liquid crystal display 100 and prevents light leakage that may be generated by a plurality of escape grooves 152 .

The cover bottom assembly 150 having the above-described structure may have different materials from each other.

More specifically, the base portion 151 and the first and second edge reinforcement portions 154a may be made of an electrolytic galvanized liner (EGI) and the center reinforcement portion 155 may be made of aluminum have. In other words, aluminum has excellent corrosion resistance, thermal conductivity and rigidity, and has a light weight, but has a high component cost. As a part of replacing aluminum, electrolytic galvanized lanthanum (EGI), which has a relatively low cost compared to aluminum and has comparatively excellent characteristics, has been used in many cases.

In the present invention, the base portion 151 on which the backlight unit 120 is mounted and the central reinforcing portion 155 are made of aluminum and the other first and second reinforcement portions 155, The two-frame reinforcing portion 154a is made of an electro-galvanized steel sheet, thereby partially improving the rigidity, preventing thermal deformation, and reducing the overall manufacturing cost. In particular, when the present invention is applied to a large-area liquid crystal display device, it is possible to maintain the rigidity while reducing the overall manufacturing cost. In addition, the LED housing 128 according to the present invention serves as a longitudinal frame reinforcement for supporting the light source and rapidly emitting heat and arranging the light sources, and the structure of the frame reinforcement in the longitudinal direction is omitted . Accordingly, the parts cost of the cover bottom assembly 150 is reduced, the overall manufacturing cost is reduced, and a lightweight and thin liquid crystal display device can be realized.

On the other hand, the rim reinforcing portion 154 and the central reinforcing portion 155 constituting the reinforcing portion 153 are shown to be separated from each other. However, the present invention is not limited to this, but may be formed integrally. In this case, it is most preferable that the reinforcing portion 153 is made of aluminum for rigidity, but it is not limited to this, and it may be made of an electro galvanized steel sheet.

As described above, it is most preferable to change the material according to the need for rigidity. However, the present invention is not limited to this, and it is possible to change the material or the thickness within a range that can reinforce the rigid structure or maintain a certain rigidity. Do. For example, the thickness of one of the base portion 151 and the reinforcing portion 153 or one of them may be adjusted to reinforce the rigidity or to maintain a certain rigidity, to reinforce the rigidity by appropriately changing the material together with the thickness, It is possible to maintain constant stiffness.

The liquid crystal panel 110 and the backlight unit 120 are covered with the top cover 140 covering the top edge of the liquid crystal panel 110 in a state where the liquid crystal panel 110 and the backlight unit 120 are surrounded by the support main body 130, And the cover bottom assembly 150 covering the back surface of the cover bottom assembly 150 are coupled to each other at the front and rear sides to be integrated through the support main body 130 to be modularized.

The light emitted from each of the plurality of LEDs 129a of the backlight unit 120 is incident on the light entrance portion of the light guide plate 123 and then refracted toward the liquid crystal panel 110 inside the light guide plate 123, 125 and the liquid crystal panel 110 while being passed through the plurality of optical sheets 121. In this case,

Here, the top cover 140 may be referred to as a case top or a top case, and the support main 130 may be referred to as a guide panel or a main support or a mold frame. The cover bottom assembly 150 may be a bottom cover assembly It can be called.

FIG. 4 is a plan view showing a base portion of a cover bottom assembly according to a preferred embodiment of the present invention. FIGS. 5A and 5B are enlarged plan views of the AB region of FIG. 4, and FIGS. Here, for convenience of explanation, the longitudinal direction is referred to as a first direction, and the direction perpendicular to the longitudinal direction is referred to as a second direction.

As shown in FIG. 4, the base portion 151 has a plurality of escape grooves 152 formed along the second direction and having an opening therein.

 Here, the plurality of escape grooves 152 include escape grooves 152 formed along the second direction in parallel with two rows corresponding to the positions of the first central reinforcing portions (155a in FIG. 3), and the second central reinforcing portions 3, 155b) along the second direction along two rows.

At this time, each of the plurality of escape grooves 152 has a predetermined length in the second direction. The first length D1 of the escape groove 152a formed on the outermost side is the second length of the escape groove 152b formed on the inner side (D2). This is because the LED assembly (129 in FIG. 1) is disposed at both edges in the first direction. That is, heat generated from a plurality of LEDs (129a in FIG. 1) can be discharged more rapidly, and heat generated by the first The length D1 is longer than the second length D2 of the inner escape groove 152b. This makes it possible to more effectively prevent thermal deformation.

Meanwhile, although not shown in the drawing, when the LED assembly is disposed only at one edge of the first direction, the length of the escape groove formed along one edge of the corresponding base may be longer than the length of the remaining escape groove.

Each of the plurality of escape grooves 152 may have a rectangular shape as shown in FIG. 5A, or an elliptical shape as shown in FIG. 5B.

The embodiments of the present invention as described above are merely illustrative, and those skilled in the art can make modifications without departing from the gist of the present invention. Accordingly, the protection scope of the present invention includes modifications of the present invention within the scope of the appended claims and equivalents thereof.

110: liquid crystal panel 120: backlight unit
121: multiple optical sheets 123: light guide plate
125: reflector 128: LED housing
150: cover bottom assembly 151: base portion
152: escape groove 153: reinforced portion

Claims (7)

A cover bolt assembly having a rectangular base plate portion and a reinforcing portion having a shape with an open center and reinforcing the base portion at the back surface of the base portion;
An LED assembly having a plurality of LEDs mounted on a printed circuit board and disposed along a longitudinal direction of the reinforcing portion; And
And an LED housing disposed on a rear surface of the printed circuit board,
The reinforcing portion
A rim reinforcing portion which rims on both edges in a direction perpendicular to the longitudinal direction of the base portion and first and second central reinforcing portions which are disposed inside the rim reinforcing portion and are arranged in parallel to each other in parallel to each other; ≪ / RTI &
The base portion
And a plurality of escape grooves formed at positions corresponding to the first and second central reinforcing portions.
The method according to claim 1,
The LED housing
And a horizontal portion that is perpendicular to the vertical portion and includes a side surface of the plurality of LEDs and a rear edge portion of the base portion.
3. The method of claim 2,
Wherein the horizontal portion of the LED housing is exposed to the outside and is in contact with the atmosphere.
3. The method of claim 2,
On the inner surface of the horizontal portion
The base portion is seated,
On the outer surface of the horizontal portion
And the reinforcing portion is partially located.
The method according to claim 1,
The plurality of escape grooves
Wherein the first central reinforcing portion and the second central reinforcing portion are arranged in two lines along a direction perpendicular to the longitudinal direction corresponding to each of the first and second central reinforcing portions.
6. The method of claim 5,
Wherein a length of an escape groove formed on an outermost side of the plurality of escape grooves is longer than a length of an escape groove formed on an inner side.
The method according to claim 1,
Wherein the rim reinforcing portion in the longitudinal direction facing each other is made of aluminum and the remaining rim reinforcing portion is made of an electrolytic galvanized liner (EGI), and the center reinforcing portion is made of aluminum Liquid crystal display device.

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