KR20130028271A - Backlight unit and liquid crystal display device including thereof - Google Patents

Abstract

The present invention relates to a backlight unit and a liquid crystal display including the same, and is characterized by applying a sheet hanger of a modified shape in order to improve the strength and reliability of the sheet hanger.

Description

BACKLIGHT UNIT AND LIQUID CRYSTAL DISPLAY DEVICE INCLUDING THEREOF}

The present invention relates to a backlight unit and a liquid crystal display device including the same, and more particularly, to a backlight unit including a sheet hanger part of a changed shape in order to reduce defects of the sheet hanger part and a liquid crystal display device including the same.

Recently, as the information society develops, the demand for the display field is increasing in various forms, and in response, various flat panel display devices, for example, liquid crystal, which have features such as thinning, light weight, and low power consumption Liquid crystal display devices, plasma display panel devices, electroluminescent display devices, and the like have been studied.

Among these, the liquid crystal display is one of the most widely used flat panel display devices, and includes a liquid crystal layer between the two substrates and the two substrates on which the pixel electrode and the common electrode are formed.

Such a liquid crystal display determines an orientation of liquid crystal molecules of a liquid crystal layer according to an electric field generated by a voltage applied to an electrode, and controls polarization of incident light to display an image.

The liquid crystal display device does not have a light emitting device, and thus a separate light source must be provided. The light source is called a backlight unit (BLU).

Here, as a light source of the backlight unit, a light emitting diode (LED) having small size, low power consumption, high reliability, and the like is widely used.

In general, the backlight unit may be broadly classified into a side type backlight unit and a direct type backlight unit.

In the side type backlight unit, the LED assembly is disposed on the side of the liquid crystal display device to supply light to the liquid crystal panel through the reflective sheet and the light guide plate, and the thickness of the LED backlight unit is mainly used in a notebook or the like.

On the other hand, in the direct type backlight unit, the LED assembly is disposed on the back of the liquid crystal display, and the light is irradiated to the front of the liquid crystal panel through the backlight unit to enable high brightness, and is mainly used for LCD TVs. .

Hereinafter, a backlight unit will be described with reference to the drawings.

1 is a partial cross-sectional view of a liquid crystal display device including a general side type backlight unit, FIG. 2 is a view showing a state in which a plurality of optical sheets are fixed to a sheet fixing portion of a cover bottom by a sheet hook portion, and FIG. Is a view referred to to explain a conventional sheet hook portion.

As shown in FIG. 1, the liquid crystal display device 1 includes a liquid crystal panel 30, a backlight unit 60, a cover bottom 70, a top cover 80, and the like.

The liquid crystal panel 30 includes an array substrate (not shown) and a color filter substrate (not shown) that are bonded to each other with a liquid crystal layer (not shown) interposed therebetween.

The first polarizing plate 12 and the second polarizing plate 22 for selectively transmitting only specific light are attached to the outer surfaces of the array substrate and the color filter substrate, respectively.

The backlight unit 60 includes a reflective sheet 42, a light guide plate 44, a plurality of optical sheets 46, and an LED assembly 50, and serves to supply light to the liquid crystal panel 30.

Here, the LED assembly 50 is composed of a plurality of LEDs 54 and the printed circuit board 52, the plurality of LEDs 54 are arranged at a predetermined interval apart from the printed circuit board 52.

At this time, the LED 54 is a high-brightness LED, which is accompanied by high heat in the process of converting electrical energy into light energy, and when the temperature of the LED is above a certain temperature (junction temperature), the efficiency of light emitted from the LED is significantly reduced. There is this.

Therefore, the LED 54 may be mounted on a printed circuit board mainly made of metal so as to easily dissipate heat generated while driving the LED.

In addition, the printed circuit board 52 may be attached to the LED housing (not shown), and although not shown, a heat sink may be further disposed on the rear surface of the printed circuit board 52.

The reflective sheet 42 serves to reflect incident light toward the liquid crystal panel 30 when incident light from the plurality of LEDs 54 passes through the rear surface of the light guide plate 44.

The light guide plate 44 serves to provide a surface light source to the liquid crystal panel 30 by allowing the light incident from the plurality of LEDs 54 to be totally reflected, and a printed pattern having a specific shape may be formed on the rear surface of the light guide plate 44. .

The plurality of optical sheets 46 include a diffusion sheet, at least one light collecting sheet, and the like, and diffuse or collect light passing through the front surface (upper side) of the light guide plate 44 to provide a uniform surface light source to the liquid crystal panel 30. To be supplied.

In addition, the plurality of optical sheets 46 includes a plurality of sheet hook portions 47 to be fixed to the cover bottom 70.

A liquid crystal panel including an array substrate and a color filter substrate bonded to each other with a liquid crystal layer (not shown) interposed therebetween is disposed on the plurality of optical sheets 46.

The cover bottom 70 serves as an overall skeleton, and the reflective sheet 42 is positioned inside the cover bottom 70, and the light guide plate 44 and the plurality of optical sheets 46 are disposed on the upper side of the reflective sheet 42. Is placed.

In addition, a plurality of sheet fixing parts 72 are formed on the cover bottom 70 to fix the plurality of optical sheets 46.

Here, the seat fixing portion 72 has a structure in which a part of the side surface of the cover bottom 70 extends, and is formed to correspond to the position of the seat hook portion 47.

After the liquid crystal panel 30 and the backlight unit 60 are disposed inside the cover bottom 70, the liquid crystal display module is completed by combining the cover bottom 70 and the top cover 80.

In this case, the liquid crystal panel 30 and the backlight unit 60 may further include a square frame-shaped support main 75.

As shown in Figs. 2 and 3, the plurality of optical sheets 46 includes a plurality of sheet hook portions 47. As shown in Figs.

Here, the sheet hook portion 47 has an opening 47a to fix the plurality of optical sheets 46 to the sheet fixing portion 72 of the cover bottom 70.

That is, the opening 47a of the seat hook portion 47 is hooked on the seat fixing portion 72 of the cover bottom 70 to prevent sagging or detachment of the plurality of optical sheets 46.

In addition, the seat hook portion 47 is required to maintain the strength to satisfy the reliability during impact or thermal expansion / contraction.

However, recently, as the liquid crystal module LCM narrows the bezel, the strength of the conventional sheet hanger 47 is weakened.

That is, in order to maintain the strength of the seat hook portion 47, the width a of the seat hook portion 47 must be kept constant. The bezel becomes narrower, and the width a of the seat hook portion 47 is maintained. Since the degree narrowed, the strength of the conventional sheet hook portion 47 is weakened.

4 and 5 are views showing a state in which the seat hook portion is damaged by an external force.

As a result of the impact test of the liquid crystal module LCM using the optical sheet 46 having the narrowed sheet hook portion 47, as shown in FIGS. 4 and 5, the sheet hook portion ( 47) A crush or tear occurred.

That is, when an external force is applied to the seat hook portion 47, stress is concentrated on the portion indicated by the dotted line so that both sides of the opening 47a may be crushed or cracked, and even a part of the seat hook portion 47 may be torn off. Can lose.

Recently, due to the narrow bezel application, the strength of the seat hook portion 47 is required despite the decrease in the width of the seat hook portion 47.

In addition, in order to support the widened optical sheet 46 due to the large area of the liquid crystal display device, an increase in the strength of the sheet hook portion 47 is required.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a backlight unit including a sheet hook portion having a changed shape and a liquid crystal display device including the same in order to reduce defects of the sheet hook portion.

The backlight unit for achieving the above object includes a plurality of optical sheets for supplying a uniform surface light source to the liquid crystal panel by diffusing or condensing the light supplied from the light source, the plurality of optical sheets are a plurality of openings And characterized in that it comprises a plurality of seat hook portion consisting of at least one connection.

Here, the opening may be circular or elliptical.

The opening may have a trapezoidal shape in which an upper side is shorter than a lower side in a direction in which the sheet hanger extends, and the connecting portion may have an inverted trapezoidal shape in which an upper side is longer than a lower side in a direction in which the sheet hanger extends.

On the other hand, the seat hook portion is preferably located to correspond to the seat fixing portion of the cover bottom.

The liquid crystal display device for achieving the above object includes a backlight unit having a plurality of optical sheets for supplying a uniform surface light source to the liquid crystal panel by diffusing or condensing the light supplied from the light source. The optical sheet is characterized in that it comprises a plurality of sheet hook portion consisting of a plurality of openings and at least one connecting portion.

Here, the opening may be circular or elliptical.

The opening may have a trapezoidal shape in which an upper side is shorter than a lower side in a direction in which the sheet hanger extends, and the connecting portion may have an inverted trapezoidal shape in which an upper side is longer than a lower side in a direction in which the sheet hanger extends.

On the other hand, the seat hook portion is preferably located to correspond to the seat fixing portion of the cover bottom.

As described above, in the backlight unit and the liquid crystal display including the same according to the present invention, the strength and reliability of the sheet hanger can be improved by changing the shape of the sheet hanger.

As a result, the defect of the seat hook part can be reduced.

1 is a partial cross-sectional view of a liquid crystal display including a general side type backlight unit.
2 is a view showing a state in which a plurality of optical sheets are fixed to the seat fixing portion of the cover bottom by the sheet hook portion.
3 is a diagram referred to explain a conventional sheet hook portion.
4 and 5 are views showing a state in which the seat hook portion is damaged by an external force.
6 is an exploded perspective view of a liquid crystal display according to an exemplary embodiment of the present invention.
7 is a view showing a seat hook portion according to the first embodiment of the present invention.
8 is a view showing a sheet hook portion according to a second embodiment of the present invention.
9 is a view showing a seat hook portion according to a third embodiment of the present invention.
10 is a view showing a seat hook portion according to a fourth embodiment of the present invention.
11 to 13 are views for reference to compare the stress intensity that the seat hook portion receives when an external force is applied.

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

6 is an exploded perspective view of a liquid crystal display according to an exemplary embodiment of the present invention, and FIG. 7 is a view showing a sheet hook part according to the first exemplary embodiment of the present invention.

As shown in FIG. 6, the liquid crystal display device 100 includes a liquid crystal panel 130, a backlight unit 160, a cover bottom 170, and a top cover 180.

The liquid crystal panel 130 plays a key role in image expression, and includes a first substrate 110 and a second substrate 120 bonded to each other with a liquid crystal layer interposed therebetween.

In this case, the area of one edge of the first substrate 110 is larger than that of the second substrate 120, and a plurality of gate wires (not shown) and data wires (not shown) are formed at one edge of the first substrate 110. A driving circuit 115 for applying a signal may be formed.

The first substrate 110 is commonly referred to as an array substrate, and a plurality of gate lines and data lines intersect on the inner surface thereof to define a pixel region Pixel.

In addition, a thin film transistor (not shown), which is a switching element, is provided in each pixel area so as to correspond to the pixel electrode (not shown) in one-to-one correspondence.

The second substrate 120 is commonly referred to as a color filter substrate, and a color filter layer (not shown) and a black matrix (not shown) are formed on an inner surface thereof.

Here, the color filter layer includes red, green, and blue color filter patterns (not shown) corresponding to red, green, and blue pixel areas (not shown).

In addition, the black matrix (not shown) covers red, green, and blue color filter patterns (not shown), and non-display elements such as gate wiring (not shown), data wiring (not shown), and thin film transistor (not shown). It serves to hide.

In addition, the second substrate 120 includes a transparent common electrode (not shown) covering the color filter layer and the black matrix.

In addition, polarizing plates (not shown) for selectively transmitting only specific light are attached to the outer surfaces of the first substrate 110 and the second substrate 120, respectively.

The backlight unit 160 includes a reflective sheet 142, a light guide plate 144, an LED assembly 150, and a plurality of optical sheets 146, and serves to supply light to the liquid crystal panel 130.

In general, the backlight unit 160 may be largely classified into a side type backlight unit and a direct type backlight unit.

In the liquid crystal display device 100 according to the present invention, a side type backlight in which the LED assembly 150 is disposed on the inner side of the cover bottom 170 is described as an example, but is not limited thereto.

The reflective sheet 142 is disposed inside the cover bottom 170, and the light guide plate 144 is disposed on the reflective sheet 142.

The reflective sheet 142 uses a plate having a high light reflectance, and when light incident from the plurality of LEDs 154 passes through the rear surface of the light guide plate 144, is reflected toward the liquid crystal panel 130 to improve the brightness of the light. Let's do it.

In the light guide plate 144, the light incident from the plurality of LEDs 154 continues to be totally reflected. Accordingly, the light may be uniformly diffused on the light guide plate 144 to provide a surface light source to the liquid crystal panel 130.

A print pattern having a specific shape may be formed on the rear surface of the light guide plate 144.

The plurality of optical sheets 146 include a diffusion sheet, at least one light collecting sheet, and the like, and diffuse or collect light passing through the front surface (upper side) of the light guide plate 144 to provide a uniform surface light source to the liquid crystal panel 130. To be supplied.

In addition, the plurality of optical sheets 146 may include a plurality of sheet hook parts 147 to be fixed to the cover bottom 170.

As shown in FIG. 7, the seat hook portion 147 according to the first embodiment of the present invention may include a connecting portion 147b between the openings 147a.

Here, the seat hook portion 147 may be positioned to correspond to the seat fixing portion 172 of the cover bottom 170, a plurality of optical sheets 146 to the sheet fixing portion 172 of the cover bottom 170 It plays a role of fixing.

That is, the plurality of openings 147a may be applied to each of the seat fixing parts 172 of the cover bottom 170 to prevent sagging or separation of the plurality of optical sheets 146.

As described above, the seat hook portion 147 according to the first embodiment of the present invention may improve the strength of the seat hook portion 147 against external force by adding a connecting portion 147b between the openings 147a.

In other words, when the at least one connecting portion 147b is added between the openings 147a, even if an external force is applied, the stress applied to both sides of the opening 147a is dispersed, thereby increasing the strength of the seat hook portion 147 against the external force. Can be improved.

As a result, even if the width a of the seat hanger 147 is narrowed due to the application of a narrow bezel, the strength of the seat hanger 147 may be improved.

The shape of the seat hook 147 as described above may be an elliptic shape as shown, but is not limited thereto, and may be a shape such as a circle or a rectangle.

This will be described later with reference to FIGS. 9 to 10.

The LED assembly 150 is arranged on one side of the light guide plate 144 and includes a plurality of LEDs 154 and a printed circuit board 152.

In this case, the plurality of light emitting diodes (LEDs) 154 may emit light having a color of red (R), green (G), and blue (B) toward the light incident surface of the light guide plate 144.

The light emitted from the plurality of LEDs 154 is transferred to the liquid crystal panel 130 through the light guide plate 144 and the plurality of optical sheets 146.

The plurality of LEDs 154 may be disposed on a surface of the printed circuit boards 152 at predetermined intervals.

The printed circuit board 152 is electrically connected to the plurality of LEDs 154.

In this case, the LED 154 is a high-brightness LED, which is accompanied by high heat in the process of converting electrical energy into light energy, and when the temperature of the LED is above a certain temperature (junction temperature), the efficiency of light emitted from the LED is significantly reduced. There is this.

Therefore, the LED may be mounted on a printed circuit board mainly made of metal so as to easily dissipate heat generated while driving the LED.

In addition, the printed circuit board 152 may be attached to the LED housing (not shown), and although not shown, a heat sink may be further disposed on the rear surface of the printed circuit board 152.

The LED assembly 150 may receive various driving signals for driving a plurality of LEDs through an external driving driver to supply light to the liquid crystal panel.

Although not shown, the LED assembly 150 may include a power supply unit (not shown) for supplying power to the plurality of LEDs 154. The power supply unit (not shown) serves to supply power to the plurality of LEDs 154.

The cover bottom 170 serves as an overall skeleton, and the LED assembly 150 is disposed on an inner side surface of the cover bottom 170 according to the present invention.

In addition, the reflective sheet 142 is positioned inside the cover bottom 170, and the light guide plate 144 and the plurality of optical sheets 146 are disposed on the reflective sheet 142 in the order of the plurality of optical sheets 146. A liquid crystal panel 130 including a first substrate 110 and a second substrate 120 bonded to each other with a liquid crystal layer (not shown) therebetween is disposed thereon.

In addition, a plurality of sheet fixing parts 172 for fixing the plurality of optical sheets 146 may be formed in the cover bottom 170.

Here, the sheet fixing part 172 may be, for example, a structure in which a part of the side surface of the cover bottom 170 is extended, and is formed to correspond to the position of the sheet hanging part 147.

In addition, the shape of the sheet fixing part 172 may be a shape suitable for the shape of the seat hook 147, for example, may be a variety of shapes such as round, oval or square.

After the liquid crystal panel 130 and the backlight unit 160 are disposed inside the cover bottom 170, the liquid crystal display module is completed by combining the cover bottom 170 and the top cover 180.

The liquid crystal display device 100 may further include a rectangular frame (not shown) positioned on the cover bottom 170 and covering the edges of the liquid crystal panel 130 and the backlight unit 160. Can be.

8 is a view showing a sheet hook portion according to a second embodiment of the present invention.

As shown in FIG. 8, the seat hook portion 247 according to the second embodiment of the present invention may include a plurality of connecting portions 247b between the openings 247a.

As described above, the seat hook portion 247 according to the second embodiment of the present invention further improves the strength of the seat hook portion 247 against external force by adding a plurality of connecting portions 247b between the openings 247a. Can be.

As the number of the connecting portions 247b is added between the openings 247a, the stress applied to both sides of the openings 247a may be further dispersed.

As a result, even if the width a of the seat hook portion 247 is narrowed due to the application of a narrow bezel, the strength of the seat hook portion 247 may be improved.

In this case, the number of the connecting portion 247b added between the openings 247a may be an appropriate number for dispersing the stress applied to both sides of the opening 247a to improve the strength of the sheet hook portion 247.

9 is a view showing a seat hook portion according to a third embodiment of the present invention.

As shown in FIG. 9, the seat hook portion 347 according to the third embodiment of the present invention may include a connecting portion 347b between the openings 347a.

The opening portion 347a may have a trapezoidal shape in which the upper side is shorter than the lower side in the direction in which the sheet hook portion 347 extends, and the connecting portion 347b may have an inverted trapezoidal shape in which the upper side is longer than the lower side as opposed to the opening portion 347a. have.

As such, when the shape of the opening 347a is a trapezoidal shape in which the upper side is shorter than the lower side in the direction in which the sheet hook portion 347 extends, both sides of the opening 347a are formed as inclined surfaces to both sides of the opening 347a. The stress applied can be further distributed in the left and right directions.

As a result, even if the width a of the seat hook portion 347 is narrowed due to the application of a narrow bezel, the strength of the seat hook portion 347 may be improved.

10 is a view showing a seat hook portion according to a fourth embodiment of the present invention.

As shown in FIG. 10, the seat hook portion 447 according to the fourth embodiment of the present invention may include a plurality of connection portions 447b between the openings 447a.

The opening 447a may have a trapezoidal shape in which the upper side is shorter than the lower side in the direction in which the sheet hook portion 447 extends, and the plurality of connection parts 447b has an inverted trapezoidal shape in which the upper side is longer than the lower side as opposed to the opening 447a. Can be.

As the number of the connecting portions 447b is added between the openings 447a as described above, the stress applied to both sides of the opening 447a may be further dispersed.

As a result, even if the width (a) of the seat hook portion 447 is narrowed due to the narrow bezel (Bezel) application, the strength of the seat hook portion 447 can be improved.

11 to 13 are views for reference to compare the stress intensity that the seat hook portion receives when an external force is applied.

As shown in Figs. 11 to 13, the stress applied to both sides of the openings is dispersed by adding at least one connecting portion between the openings of the seat hook portions.

In Fig. 11, the maximum value of the stress Max applied to both sides of the opening is 317.05Mpa, in Fig. 12 the maximum value of the stress is 175.98Mpa, and in Fig. 13 the maximum value of the stress Max is 127.58Mpa. to be.

That is, it can be seen that the maximum value of the stress applied to both sides of the opening decreases as the number of connecting portions added between the openings of the seat hook portion increases.

12 and 13, it can be seen that the stress applied by the external force is distributed to the connection part, and as the number of the connection parts increases, the value of the stress applied to the connection part also decreases.

Therefore, the optical sheet according to the embodiment of the present invention can improve the strength and reliability of the sheet hook portion by providing the optical sheet having the sheet hook portion according to the first to fourth embodiments.

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.

100: liquid crystal display device 130: liquid crystal panel
142: reflective sheet 144: light guide plate
146: optical sheet 147: sheet hook portion
150: LED assembly 160: backlight unit
170: cover cover 180: top cover

Claims (8)

It includes a plurality of optical sheets for supplying a uniform surface light source to the liquid crystal panel by diffusing or condensing the light supplied from the light source,
The plurality of optical sheets includes a plurality of sheet hook portion consisting of a plurality of openings and at least one connecting portion.
The method of claim 1,
And the opening is circular or elliptical.
The method of claim 1,
The opening has a trapezoidal shape in which an upper side is shorter than a lower side in a direction in which the sheet hanger extends,
And the connecting portion has an inverted trapezoidal shape whose upper side is longer than the lower side in the extending direction of the sheet hook portion.
The method of claim 1,
And the seat hook portion is positioned to correspond to the seat fixing portion of the cover bottom.
It comprises a backlight unit having a plurality of optical sheets for supplying a uniform surface light source to the liquid crystal panel by diffusing or condensing the light supplied from the light source,
The plurality of optical sheets includes a plurality of sheet hook portion consisting of a plurality of openings and at least one connecting portion.
The method of claim 5,
And the opening is circular or elliptical.
The method of claim 5,
The opening has a trapezoidal shape in which an upper side is shorter than a lower side in a direction in which the sheet hanger extends,
And the connecting portion has an inverted trapezoidal shape whose upper side is longer than the lower side in the extending direction of the sheet hook portion.
The method according to claim 6,
And the seat hook portion is positioned to correspond to the seat fixing portion of the cover bottom.

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