KR102436555B1 - Backlight unit and liquid crystal display module having the same - Google Patents

Abstract

The present invention provides a backlight unit capable of preventing thermal deformation of a light guide plate and flow of the light guide plate and a liquid crystal display module having the same. a holder wing fixed to the panel; Each of the holder wings has a holder protrusion that protrudes from the non-light incident surface of the light guide plate and comes into contact with the light guide plate.

Description

A backlight unit and a liquid crystal display module having the same

The present invention relates to a backlight unit capable of preventing thermal deformation of a light guide plate and flow of the light guide plate, and a liquid crystal display module having the same.

In general, a liquid crystal display (LCD) is one of the flat panel display devices that display an image using liquid crystal, and has advantages of being thinner and lighter than other display devices, and having a low driving voltage and low power consumption. It is widely used throughout.

Such a liquid crystal display includes a liquid crystal panel in which liquid crystal cells are arranged in a matrix, and a backlight unit irradiating light to the liquid crystal panel.

A general backlight unit is classified into an edge type and a direct type according to an arrangement structure of a lamp. The edge type has a structure in which at least one light source is disposed on at least one side of the light guide plate, and has a structure in which a plurality of direct light sources are disposed under the diffusion plate. In recent years, the edge type is mainly used due to the slimming trend of liquid crystal display devices.

The edge-type backlight unit includes a light guide plate to propagate the light emitted from the light source to the entire area of the liquid crystal display panel. However, there is a problem in that the light guide plate is thermally deformed by the high-temperature heat emitted from the light source, and the light guide plate flows due to an external impact. In order to solve this problem, a structure in which a holder is attached to a bottom cover or a guide panel using double-sided tape to prevent movement of the light guide plate has been proposed. However, when the holder is fixed using a double-sided tape, there is a problem in that the cost increases because the double-sided tape and the double-sided tape attaching process are additionally required. In addition, there is a problem in that when the double-sided tape is attached, misalignment occurs due to an operator's work error, and the adhesive force of the double-sided tape is lowered during rework, making it impossible to reuse the double-sided tape during rework.

In order to solve the above problems, the present invention provides a backlight unit capable of preventing thermal deformation of the light guide plate and flow of the light guide plate, and a liquid crystal display module having the same.

In order to achieve the above technical object, the holder portion of the holder accommodating portion of the guide panel according to the present invention includes a holder wing portion fixed to the guide panel; Each of the holder wings has a holder protrusion that protrudes from the non-light incident surface of the light guide plate and comes into contact with the light guide plate.

Here, the holder protrusion has a curved shape, and the apex of the curved holder protrusion is closer to the outer surface of the guide panel after the light guide plate is expanded than before the light guide plate is expanded.

In the present invention, the flow of the light guide plate can be prevented by using the holder protrusion fitted to the guide panel, and deformation of the light guide plate that is expanded due to thermal expansion can be prevented. In addition, in the present invention, since the holder part is inserted into the holder accommodating part by using the self-elasticity of the holder part without a double-sided adhesive, workability can be improved. In addition, in the present invention, since the holder portion can be inserted into the holder receiving portion without the double-sided tape, cost increase and misalignment caused by the double-sided tape can be prevented. In addition, in the present invention, the rework process is easy because the holder part is fixed by an inserting method instead of an attaching method using a double-sided tape.

1 is a cross-sectional view illustrating a liquid crystal display module according to a first embodiment of the present invention.
Figure 2a is a perspective view showing in detail the guide panel shown in Figure 1,
Figure 2b is a perspective view showing a holder portion inserted into the guide panel shown in Figure 2a,
FIG. 2C is a perspective view illustrating a holder cover part formed to cover the holder part shown in FIG. 2B .
3A and 3B are plan views illustrating deformation of the holder part before and after thermal expansion of the light guide plate according to the present invention.
4 is a cross-sectional view illustrating a liquid crystal display module according to a second exemplary embodiment of the present invention.
5 is a perspective view illustrating a holder cover unit integrated with the guide panel shown in FIG. 4 .

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings and examples.

1 is a cross-sectional view showing a liquid crystal display module according to the present invention.

The liquid crystal display module illustrated in FIG. 1 includes a liquid crystal panel 130 and a backlight unit.

The liquid crystal panel 130 implements an image by using the light emitted through the backlight unit. To this end, the liquid crystal panel 130 includes an upper substrate 132 , a lower substrate 134 , an upper polarizing plate 136 , and a lower polarizing plate 138 .

A color filter for realizing color, a black matrix for preventing light leakage, and a common electrode forming an electric field with the pixel electrode are formed on the upper substrate 132 . Meanwhile, the common electrode is formed on the lower substrate 134 when a horizontal electric field or a fringe electric field is formed with the pixel electrode. A gate line and a data line formed to cross each other, a thin film transistor formed at an intersection thereof, and a pixel electrode connected to the thin film transistor are formed on the lower substrate 134 .

The upper substrate 132 and the lower substrate 134 are bonded to face each other with the liquid crystal layer interposed therebetween. The liquid crystal layer is rotated by the electric field between the pixel electrode and the common electrode, and the amount of light transmission is determined according to the degree of rotation of the liquid crystal layer.

The lower polarizing plate 138 is attached to the lower surface of the lower substrate 134 , the upper polarizing plate 136 is attached to the upper surface of the upper substrate 132 , and each of the lower polarizing plate 138 and the upper polarizing plate 136 receives incident light. Only the linearly polarized light parallel to its own transmission axis is selectively transmitted.

The backlight unit is disposed under the liquid crystal panel 130 to provide light to the liquid crystal panel 130 . To this end, the backlight unit includes an accommodating part for providing an accommodating space, a light source assembly 140 , a light guide plate 122 , a plurality of optical sheets 128 and a reflective sheet 124 accommodated in the accommodating space.

The light source assembly 140 includes a light source 142 and a light source circuit board 144 .

At least one light source 142 is mounted on the light source circuit board 144 to supply a driving voltage to the light source 142 . The light source 142 is formed of any one of a light emitting diode (LED), a cold cathode fluorescent lamp (CCFL), and an external electrode fluorescent lamp (EEFL). The light emitted from the light source 142 is directly incident into the light guide plate 122 , or is reflected by a light source housing (not shown) formed to surround the light source 142 and is incident into the light guide plate 122 . In addition, the light source 142 is formed to face at least one side (light incident surface) of the light guide plate 122 . For example, the light source 142 may be formed to face both sides of the light guide plate 122 to reduce power consumption and cost.

The plurality of optical sheets 128 includes at least one diffusion sheet, a prism sheet, and a luminance enhancing sheet positioned on the light guide plate 122 . The diffusion sheet is located on the light guide plate 122 and controls the direction of the light so that the light travels toward the light collecting sheet while dispersing the light incident through the light guide plate 122 . The light collecting sheet condenses the light diffused through the diffusion sheet toward the liquid crystal panel 130 . At this time, the light passing through the light collecting sheet travels perpendicular to the liquid crystal panel 130 . The luminance enhancing sheet enhances luminance between the prism sheet and the lower polarizing plate 138 .

The reflective sheet 124 is disposed under the light guide plate 122 , and reflects light emitted from the light source 142 to the outside through the rear surface of the light guide plate 122 toward the light guide plate 122 .

The light guide plate 122 is disposed to face the light source 142 to guide the light incident from the light source 142 , diffuses and condenses the light guided by the light guide plate 122 , and emits it to the front surface of the light guide plate 122 .

The receiving unit includes a lower case 146 and a guide panel 112 .

The lower case 146 serves as an outer cover of a display device such as a notebook computer, a mobile device, and a TV. The edge region of the lower case 146 is coupled to the guide panel 112 . Accordingly, the light source assembly 140 , the light guide plate 122 , the optical sheet 128 , and the reflective sheet 124 are accommodated in the storage space provided by the lower case 146 and the guide panel 112 .

The guide panel 112 is formed by extrusion molding using a metal such as aluminum (Al). As shown in FIG. 2A , the guide panel 112 includes a holder accommodating part 114 in which the holder part 150 can be accommodated in an area facing the non-light incident surface excluding the light incident surface of the light guide plate 122 , and a holder cover. The portion 118 is formed to provide a cover receiving portion 116 that can be accommodated. To this end, the guide panel 122 includes first to third support portions 112a, 112b, and 112c arranged in a step shape.

The first support part 112a is formed in a rectangular band shape to provide a storage space in which the light guide plate 122 can be accommodated. A second support part 112b higher than the height of the holder part 150 is formed on the first support part 112a to provide a groove-shaped holder accommodating part 114, and the holder accommodating part 114 is formed on the second support part 112b. ) A third support portion 112c higher than the height of the holder cover portion 118 is formed to provide the groove-shaped cover accommodation portion 116 having a larger area.

The holder accommodating part 114 includes first and second accommodating spaces 114a and 114b. The first accommodation space 114a is a space in which the holder protrusion 154 is accommodated as shown in FIG. 2B . The first accommodating space 114a is formed in such a way that a region facing the non-light incident surface of the light guide plate 122 is opened so that the holder protrusion 154 can contact the non-light incident surface of the light guide plate 122 . The second accommodating space 114b is a space in which the holder wing part 152 is accommodated, and is formed to be narrower than the first accommodating space 114a. The second accommodating space 114b has a closed region facing the non-light incident surface of the light guide plate 122 to prevent the holder 150 from being separated toward the non-light incident surface of the light guide plate 122 . And, as shown in FIG. 2c , the holder cover part 118 of a sponge material is accommodated in the cover accommodation part 116 so as to cover the first and second accommodation spaces 114a and 114b, so that the holder 150 is liquid crystal. It is possible to prevent separation toward the display panel 130 .

The holder unit 150 accommodated in the first and second accommodation spaces 114a and 114b limits the movement of the light guide plate 122 . To this end, the holder part 150 includes a holder protrusion 154 and a holder wing part 152 as shown in FIGS. 3A and 3B .

The holder wings 152 are located on both sides of the holder protrusion 154 , and are accommodated in the second accommodation space 114b to prevent the holder 150 from being separated toward the light guide plate 122 .

The holder protrusion 154 protrudes from the holder wing 152 toward the non-light incident surface of the light guide plate 122 as shown in FIG. 3A . The holder protrusion 154 contacts the non-light incident surface of the light guide plate 122 at low temperature and room temperature to prevent the light guide plate 122 from flowing. In addition, as shown in FIG. 3B , the holder protrusion 154 is compressed and deformed according to the thermal expansion of the light guide plate 122 when thermal expansion of the light guide plate 122 occurs at a high temperature to fix the light guide plate 122 . That is, when the holder protrusion 154 is formed in a curved shape, since the holder protrusion 154 is pressed by the thermally expanded light guide plate 122 , the holder protrusion 154 is deformed with a small curvature. That is, the apex of the holder protrusion 154 is deformed closer to the outer surface of the guide panel 112 after the thermal expansion of the light guide plate 122 than before the thermal expansion of the light guide plate 122 .

Meanwhile, the holder part 150 is formed of a material having a hardness that expands when the light guide plate 122 is contracted and can be contracted when the light guide plate 122 is expanded. For example, the holder 150 is formed of a silicon material having a hardness of 50 to 80. Here, when the hardness of the holder part 150 is less than 50, the shape of the holder protrusion part 154 cannot be maintained at low and normal temperatures, and thus the flow of the light guide plate 122 cannot be prevented. When the hardness of the holder part 150 exceeds 80, since the holder part 150 is not deformed according to the deformation of the light guide plate 122 , the effect of preventing thermal expansion of the light guide plate 122 cannot be obtained.

In addition, the holder 150 is preferably formed in a non-reflective color so as not to reflect the light passing through the non-light incident surface of the light guide plate 122 . However, since the holder 150 is located in the bezel area, it may be formed in white.

As such, the holder part 150 prevents the flow of the light guide plate 122 by maintaining the shape of the holder protrusion 154 at low and room temperature as it is, and when the light guide plate 122 is thermally expanded, the holder protrusion 154 is compressed to thermally expand. It is possible to prevent deformation of the light guide plate 122 that is expanded by the .

On the other hand, when assembling the holder unit 150, when the operator presses the holder unit 150 having elasticity, the holder unit 150 is compressed by the elasticity, and the operator places the compressed holder unit 150 into the holder receiving unit. (114) is inserted. The holder unit 150 inserted into the holder receiving unit 114 is restored to its original shape. As described above, in the present invention, since the holder unit 150 is inserted into the holder receiving unit 114 by using the elasticity of the holder unit 150 without a double-sided adhesive, workability can be improved. In addition, in the present invention, since the holder 150 can be inserted into the holder accommodating part 114 without the double-sided tape, it is possible to prevent an increase in cost and misalignment due to the double-sided tape. In addition, in the present invention, the rework process is easy because the holder unit 150 is fixed by a fitting method instead of an attachment method using a double-sided tape.

4 is a cross-sectional view illustrating a liquid crystal display device according to a second exemplary embodiment of the present invention.

The liquid crystal display shown in FIG. 4 has the same components as the liquid crystal display shown in FIG. 1 , except that the holder cover 118 is integrally formed with the guide panel 112 . Accordingly, detailed descriptions of the same components will be omitted.

The guide panel 112 is formed by injection molding using a plastic material. The second support portion 112b of the guide panel 112 is formed to be integrated with the holder cover portion 118 . At this time, the holder cover portion 118 is formed of a plastic material that is the same material as the guide panel 112 .

The holder cover part 118 may be formed to cover the holder accommodation part 114 in which the holder part 150 is accommodated, thereby preventing the holder part 150 from being separated toward the liquid crystal display panel 130 .

In the second embodiment of the present invention as described above, since the shape of the holder protrusion 154 can be maintained at low temperature and room temperature, the flow of the light guide plate 122 is prevented, and when the light guide plate 122 is thermally expanded, the holder protrusion 154 is By being compressed, it is possible to prevent deformation of the light guide plate 122 that is expanded due to thermal expansion.

Meanwhile, in the present invention, one holder unit 150 is disposed on each non-light incident surface of the light guide plate 122 as an example, but a plurality of holder units 150 are disposed on each non-light incident surface of the light guide plate 122 or At least one holder unit 150 may be disposed on at least one non-light incident surface of the maximum three non-light incident surfaces of the light guide plate 122 .

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and it is known in the art to which the present invention pertains that various substitutions, modifications and changes are possible without departing from the technical spirit of the present invention. It will be clear to those who have the knowledge of

112: guide panel 114: holder accommodating part
116: cover receiving portion 118: holder cover portion
122: light guide plate 150: holder part
152: holder wing 154: holder protrusion

Claims (12)

a light guide plate;
A guide including a first support part having a rectangular band shape having a receiving space in which the light guide plate is accommodated, and a second support part positioned on the first support part and having a holder receiving part in an area facing the non-light incident surface except for the light incident surface of the light guide plate panel;
and a holder unit accommodated in the holder receiving unit,
the holder part
a holder wing unit accommodated in the holder receiving unit and fixed to the guide panel;
and a holder protrusion protruding from each of the holder wings to a non-light incident surface of the light guide plate and contacting the light guide plate;
The holder receiving part
a first accommodating space in which the holder protrusion is accommodated and in which an area facing the non-light incident surface is opened;
and a second accommodating space in which the holder wing is accommodated and an area facing the non-light incident surface is closed. The method of claim 1,
The holder protrusion is formed in a curved shape,
The apex of the curved holder protrusion is closer to the outer surface of the guide panel after the light guide plate is expanded than before the light guide plate is expanded. delete The method of claim 1,
The backlight unit further comprising a holder cover disposed on the guide panel to cover the first and second storage spaces. 5. The method of claim 4,
The holder cover part is made of a sponge material, and the guide panel is a backlight unit made of a metal material. 5. The method of claim 4,
A backlight unit in which the guide panel and the holder cover are integrated with the same material. 7. The method of claim 6,
The holder cover part and the guide panel are made of a plastic material. The method of claim 1,
The holder part is a backlight unit made of a silicon material having a hardness of 50 to 80. a liquid crystal display panel for displaying an image;
9. A liquid crystal display module comprising the backlight unit of any one of claims 1, 2, and 4 to 8 for supplying light to the liquid crystal display panel. a liquid crystal display panel for displaying an image;
a light guide plate positioned below the liquid crystal display panel;
A first support part having a rectangular band shape having a receiving space in which the light guide plate is accommodated, and a second support part positioned on the first support part and having a groove-shaped holder receiving part in a region facing a non-light incident surface except for a light incident surface of the light guide plate and a guide panel disposed on the second support part and including a third support part on which an edge of the liquid crystal display panel is seated, the guide panel having a groove-shaped cover receiving part having a larger area than the holder receiving part; and
and a holder unit accommodated in the holder receiving unit,
the holder part
a holder wing unit accommodated in the holder receiving unit and fixed to the guide panel; and
and a holder protrusion protruding from each of the holder wings to a non-light incident surface of the light guide plate and contacting the light guide plate;
The holder receiving part
a first storage space in which the holder protrusion is accommodated and an area facing the non-light incident surface is opened;
and a second accommodating space in which the holder wing is accommodated and an area facing the non-light incident surface is closed. 11. The method of claim 10,
The holder wing portion is fixed to the guide panel by the closed shape of the second accommodation space. 11. The method of claim 10,
The liquid crystal display module further comprising a holder cover portion vertically spaced apart from the holder portion and disposed on the second support portion of the guide panel to cover the first and second accommodation spaces.

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