KR101794647B1 - Liquid Crystal Display Device - Google Patents

Abstract

The present invention relates to a liquid crystal display device in which a heat pipe is disposed in a structure having an edge type backlight to uniformly raise the surface temperature of a liquid crystal panel to improve a response speed, A light source disposed on both sides of the light guide plate, a cover bottom housing the light source and the light guide plate, And a plurality of heat pipes disposed on the bottom surface of the cover bottom and spaced apart from each other.

Description

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

The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device in which a heat pipe is disposed in a structure having an edge type backlight to uniformly raise the surface temperature of the liquid crystal panel to improve the response speed.

Specific examples of the flat panel display include a liquid crystal display (LCD), a plasma display panel (PDP), a field emission display (FED), an electroluminescent display and a luminescence display device (ELD). These devices commonly use a flat panel display panel for realizing an image. The flat panel display panel has a pair of transparent insulation layers And has a structure in which substrates are bonded together.

Among them, the liquid crystal display device displays an image by adjusting the light transmittance of the liquid crystal using an electric field. To this end, the image display apparatus includes a display panel having a liquid crystal cell, a backlight unit for irradiating the display panel with light, and a drive circuit for driving the liquid crystal cell.

The backlight unit is divided into an edge type and a direct type according to the arrangement of the light sources.

Hereinafter, a conventional liquid crystal display device will be described with reference to the accompanying drawings.

1 is a cross-sectional view showing a conventional liquid crystal display device.

Fig. 1 shows a liquid crystal display device having an edge type backlight. Accordingly, the conventional liquid crystal display device includes a panel 25, a light guide plate 12 disposed under the panel 25, LEDs 16 serving as light sources on both sides of the light guide plate 12, A cover bottom 10 for accommodating the LED 12 and the LED 16 together and a case top 20 for covering the edge and sides of the panel 25 and meeting the cover bottom 10.

A reflective plate 11 is further provided between the cover bottom 10 and the light guide plate 12 so that the light emitted from the LED 16 and transmitted to the light guide plate 12 is transmitted to the upper side of the panel 25 .

The LED 16 is disposed on the LED substrate 15, and the LED substrate 15 is attached to the side surface of the cover bottom.

At this time, the cover bottom 10 has an inverted '' shape in cross section, and has four sides raised from the lower surface and the four sides of the lower surface. Then, the LED substrate 15 is bonded to both side surfaces of the cover bottom 10 facing each other. In this case, an adhesive layer may be interposed between the LED substrate 15 and the cover bottom 10.

The panel 25 includes upper and lower substrates opposed to each other and a liquid crystal layer therebetween. A TCP or COF film including a source drive IC (not shown) is connected to the surface of the lower substrate.

However, the conventional liquid crystal display device has the following problems.

In a liquid crystal display device provided with an edge type backlight, since the light source is located only on both sides of the panel, there is a phenomenon that heat is concentrated only on a part of the side of the panel. Edge edgings of these heat are observed to be dominant and worsening.

However, the liquid crystal in the panel is very sensitive to the temperature change. Therefore, it is necessary to maintain a condition of 30 ° C or more when driving, and a fast moving image such as a moving image can be stably displayed without afterimage.

However, the panel does not include a device that generates a large amount of heat, and a component that can greatly affect the panel side in the liquid crystal display device is a light source. In the case of an edge type, So that the temperature change of the surface of the panel, particularly the temperature change of the central portion, is very small. As a result, there is a problem that the driving response speed is lowered in a moving image or the like.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a liquid crystal display device in which a heat pipe is disposed in a structure having an edge type backlight to uniformly raise the surface temperature of a liquid crystal panel, There is a purpose.

According to an aspect of the present invention, there is provided a liquid crystal display comprising: a liquid crystal panel; a light guide plate disposed under the liquid crystal panel; a light source disposed at both sides of the light guide plate; a cover bottom for accommodating the light source and the light guide plate; And a plurality of heat pipes disposed on the bottom surface of the cover bottom and spaced apart from each other.

The plurality of heat pipes may be disposed at equal intervals. Alternatively, the plurality of heat pipes may be selectively disposed in an area adjacent to the light source.

The heat pipe includes first and second capillaries facing each other, a vapor layer between the first and second capillaries, and a shell surrounding the outer periphery of the first and second capillaries, ). ≪ / RTI >

Also, the heat pipe may be on a plate.

Meanwhile, the heat pipe may contact the cover bottom with an adhesive layer interposed therebetween, or may be mechanically fastened to the cover bottom.

The light source may be a light emitting diode (LED).

A substrate to which the light source is connected; And a housing for fixing the substrate to the cover bottom side. The light pipe further includes a reflection plate disposed under the light pipe, and the reflection plate is in contact with the heat pipe. In this case, the heat transfer path from the light source is the light source, the substrate, the housing, the heat pipe, the reflection plate, the light guide plate, and the liquid crystal panel.

The liquid crystal display of the present invention as described above has the following effects.

A liquid crystal display device of the present invention is a liquid crystal display device in which a heat pipe is disposed adjacent to a light source positioned on both sides of a light guide plate so that heat generated from the light source is transmitted from a housing of a light source to a heat pipe, It is possible to uniformly transmit heat to the entire liquid crystal panel through the light guide plate and the optical sheet.

Accordingly, the temperature of the surface of the liquid crystal panel is increased, so that the liquid crystal sensitive to temperature can react quickly. As a result, the temperature of the liquid crystal can be maintained at 30 ° C or more at which the moving image or the rapidly changing image can be displayed in the entire liquid crystal panel, and the reaction speed of the liquid crystal (MPRT: Motion Picture Response Time) can be improved. Thus, a clear image can be displayed without any afterimage.

In addition, by the arrangement of the heat pipes, uniform heat distribution is possible throughout the liquid crystal panel, so that the temperature is not concentrated only in a specific region.

1 is a cross-sectional view of a conventional liquid crystal display
2 is a sectional view showing a liquid crystal display device of the present invention
Fig. 3 is a plan view showing a lower inner surface of the cover bottom of Fig. 2
4 is a flowchart showing a thermal path of the liquid crystal display device of the present invention
Figure 5 is a cross-sectional view of the heat pipe of Figure 3;
6 is a plan view illustrating a liquid crystal display device according to another embodiment of the present invention.
7 is a view showing the thermal distribution simulation of Fig. 6
Figs. 8 and 9 are diagrams showing a plurality of regions between a center portion and an edge portion when the heat pipe is not used and applied

Hereinafter, a liquid crystal display device according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 is a cross-sectional view of a liquid crystal display device according to the present invention, and FIG. 3 is a plan view showing a lower inner surface of the cover bottom of FIG.

2, the liquid crystal display of the present invention includes a liquid crystal panel 100, a light guide plate 120 under the liquid crystal panel 100, a light source 131 located at both sides of the light guide plate 120, A cover bottom 140 for accommodating the light source 131 and the light guide plate 120 and a plurality of heat pipes 125 disposed on the bottom surface of the cover bottom 140 so as to be spaced apart from each other. 3 is a plan view of an inner bottom surface of the cover bottom 140. A light source 131 is disposed along the upper and lower sides of the inner bottom surface of the cover bottom 140, And a plurality of heat pipes 125 are disposed between the left side and the right side of the inner bottom surface of the cover bottom 140 in a direction intersecting the direction of the light source 131.

The heat pipe 125 is provided to distribute the heat from the light source 131 to the front surface of the liquid crystal panel 100 uniformly and is disposed at least in a region adjacent to the light source 131, And are spaced apart from each other for dispersion.

As shown in FIG. 3, the heat pipes 125 may be arranged at equal intervals, or alternatively, may be arranged to be concentrated in a region adjacent to the light source 131.

The heat pipe may be connected to the cover bottom 140 through an adhesive layer (not shown) or may be fastened to the cover bottom 140 through a mechanical connection such as a hole or a hook.

The liquid crystal panel 100 includes first and second substrates 101 and 102 opposed to each other with a liquid crystal layer interposed therebetween and first and second substrates 101 and 102 disposed on the rear surfaces of the first and second substrates 101 and 102, 1, and a second polarizing plate 103, 104, respectively. Though not shown, a thin film transistor array is formed on the first substrate 101, and a color filter array is formed on the second substrate 102.

A plurality of optical sheets 110, 111, 112, 113, and 114 are disposed on the light guide plate 120 to transmit the light from the lower portion to the liquid crystal panel 100 with minimal loss. Examples of the optical sheet include a prism sheet and a diffusion sheet.

Also, the light source 131 may be a lamp or a light emitting diode (LED). The experimental example to be described later is an example in which the light source 131 is an LED. When a light source is provided as an LED, there is an advantage in that power reduction and color sharpness are higher than those of a lamp.

When the light source 131 is an LED, a substrate 130 to which the LEDs are connected and a housing 135 that fixes the substrate 130 to the cover bottom 140 side are further included.

The reflection plate 121 may be arranged to be in contact with the heat pipe 125 in order to concentrate and transmit light to the upper portion of the light guide plate 120. 2, the heat generated from the light source 131 passes through the substrate 130, the housing 135, the heat pipe 125, the reflection plate 121, and the light guide plate 120 in this order And is transmitted to the liquid crystal panel 100 through the upper optical sheet 110 or passes through the substrate 130, the housing 135 and the cover bottom 140 and is then connected to the heat pipe 125, The reflection plate 121 and the light guide plate 120 may be transmitted in the order of the pipe 125, the reflection plate 121, and the light guide plate 120, and may be transmitted to the liquid crystal panel 100 via the upper optical sheet 110. This is because the heat generated from the light source 131 is dispersed in a plane through the heat pipe 125 dispersedly disposed on the surface of the light guide plate 120 so that the temperature does not rise only at a specific portion of the liquid crystal panel 100, To apply heat. This makes it possible to obtain a driving speed enough to drive a moving image particularly in the central portion of the liquid crystal panel 100.

In addition, the case top 150 is further formed to surround the edge and the side of the liquid crystal panel 100 and the side of the cover bottom 140. A support main 145 is further provided between the case top 150 and the cover bottom 140 to support the support main 145 therebetween. At this time, the support main body 145 has protrusions on the lower side of the liquid crystal panel 100, and supports the liquid crystal panel 100. At this time, the protrusion is positioned between the optical sheet 110 and the liquid crystal panel 100. In this case, the projecting portion may be omitted. Further, since the buffer member 147 is further provided between the liquid crystal panel 100 and the protrusion, it is possible to prevent the liquid crystal panel 100 from being impacted during assembly.

4 is a flowchart showing a thermal path of the liquid crystal display device of the present invention.

When the light source 131 is turned on, the heat transfer path is viewed in the order of the medium. The light source 131, the substrate 130, the housing 135, the heat pipe 125, the reflection plate 121, A light guide plate 120, an optical sheet 110, and the liquid crystal panel 100.

That is, with reference to FIG.

When the LED functioning as the light source 131 is turned on (110S), heat is generated in the LED, and heat is directly transmitted to the housing 135 through the substrate 130 connected to the LED 120S. Here, the housing 135 is structurally connected to the cover bottom 140 and a part of the upper surface of the housing 135 is connected to the heat pipe 125, and the heat transfer from the housing 135 to the heat pipe 130S is performed. And the brightness enhancement effect is obtained. This is because the heat is not concentrated in the LED forming area and the heat can be dispersed by the presence of the plural spaced heat pipes 125.

Heat is spread through the light guide plate 120 and the plurality of optical sheets 110 in contact with the heat pipe 125, and heat is transmitted to the liquid crystal panel 100 (140S). When the heat is transferred to the liquid crystal panel 100, the heat is uniformly transmitted to each region of the liquid crystal panel 100, and the temperature of the liquid crystal sensitive to the temperature is increased to improve the driving speed, particularly, the Motion Picture Response Time (MPRT) .

On the other hand, the heat pipe is arranged on a plate, and it is possible to make the backlight unit slimmer, and it is possible to easily contact the reflector 121 and the housing bottom 135 located at the upper portion thereof with the cover bottom 140 .

5 is a cross-sectional view showing the heat pipe of FIG.

5, the heat pipe 125 includes first and second capillary structures 1251 and 1252 opposed to each other, and a vapor layer (not shown) between the first and second capillaries 1251 and 1252 And a shell 1253 enclosing the outer surfaces of the first and second capillaries 1251 and 1252 and blocking the inner vapor layer 1255.

Here, the first and second capillaries 1251 and 1252 each include a liquid, and the capillary force varies depending on the temperature, thereby changing the flow of the vapor in the vapor layer 1255 therebetween. For example, the liquid in the first and second capillaries 1251 and 1252 may be acetone. At this time, when acetone is supplied with heat, it is vaporized and moves to a lower temperature side, and flows to maintain thermal equilibrium.

FIG. 6 is a plan view of a liquid crystal display device according to another embodiment of the present invention, and FIG. 7 is a diagram illustrating a thermal distribution simulation of FIG.

The heat pipe 225 shown in FIG. 6 selectively shows a heat pipe disposed in an area adjacent to the light source. Only the lower inner surface 240 of the cover bottom is shown for convenience. The remaining components are the same as the structure of FIG. 2 described above.

In this case, when the distribution of the heat is simulated as shown in FIG. 7 in the arrangement of FIG. 6, it can be seen that the heat is stronger at the line where the heat pipe 225 is disposed, at the central portion and at the edge. This means that heat is dispersed in the central portion and the heat pipe corresponding region, which are less affected by the light source disposed on the side portion, thereby improving the driving speed of the liquid crystal by improving the driving temperature. In addition, the heat is transmitted to the panel side through the heat pipe, and the heat can be prevented from concentrating in the light source itself, thereby preventing deterioration of the light source and improving the brightness.

More specifically, the difference in the surface temperature of the panel when the heat pipe is not used is examined.

Figs. 8 and 9 are views showing a plurality of regions between a center portion and an edge portion when heat pipes are not used and applied. Table 1 shows the temperatures measured corresponding to the respective areas of the panel surfaces of Figs. 8 and 9. Fig.

point No heatpipe (℃) Heat pipe application (℃) One 37.2 37.0 2 38.6 38.2 3 38.9 38.6 4 29.5 31.4 5 30.0 32.3 6 35.9 36.2 7 35.2 33.7 8 36.8 34.2 9 36.0 34.0

In Figs. 8 and 9, the regions 1 to 9 are selected from the left to the center with respect to the center of the liquid crystal panel, and are spaced at the same interval in order from the upper left to the lower right.

Here, it should be noted that when the liquid crystal panel is divided into an upper portion, a middle portion, and a lower portion, it is a region corresponding to the middle portion and the lower portion.

In other words, as shown in Fig. 8, there were regions where the temperature was not higher than 30 占 폚 when the heat pipe was not used, and about 2 占 폚 It can be observed that there is a temperature rise of < RTI ID = 0.0 > Particularly, in the region No. 4, when the heat pipe is not used, the temperature rises to 31.4 ° C in the region not reaching 30 ° C, and thus the reaction rate of the liquid crystal can be expected to be improved.

In addition, it can be seen that the temperature is lowered when the heat pipe is applied to the region 7 to 9 corresponding to the lower portion, compared with the case where the heat pipe is not used as a whole. This means that the heat pipe is distributing heat, and it can be seen that heat is distributed in a direction to make the temperature uniform throughout the panel. Thus, the luminance can be predicted by the heat distribution. Further, the temperature is maintained at about 33 占 폚 or higher, which is about 2 占 폚 downward, and even if there is such a downward temperature, the driving speed of the liquid crystal is maintained at a certain level.

The temperature observation result described above is based on the structure of Fig. 6 in which two heat pipes are disposed on both sides of the heat source adjacent to the light source, so that uniform distribution of heat can be expected more improved when the heat pipes are arranged more uniformly will be.

Hereinafter, values obtained by comparing the luminance of the surface of the liquid crystal panel with the case where the heat pipe is not used and the case where the heat pipe is applied will be described with reference to Table 2. In this case, when the heat pipe is applied, the experiment is performed based on the case where the arrangement of the heat pipes is arranged more densely than the case of FIG.

point When heat pipe is not used (nit) When applying heat pipes (nit) One 384 429 2 385 405 3 429 457 4 334 365 5 419 417 6 441 440 7 415 454 8 416 460 9 424 437

According to Table 2, it can be seen that the luminance is elevated to a level of about 30 nit or more at the upper and lower edges, especially at the time of application, compared to when no heat pipe is used. In the central part, the luminance values are almost the same.

On the other hand, there is an experimental result that the MPRT of the liquid crystal is reduced by about 1 ms when the temperature at the center of the surface of the panel rises by about 1 캜 compared with, for example, when the heat pipe is not used. This facilitates the transfer of the heat generated in the light source to the liquid crystal panel by the above-mentioned heat pipe arrangement, thereby making the elevated temperature of the liquid crystal panel uniform, thereby improving the reaction speed of the liquid crystal.

While the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. Will be apparent to those of ordinary skill in the art.

100: liquid crystal panel 110: optical sheet
120: light guide plate 121: reflector
125: heat pipe 130: substrate
131: light source 135: housing
140: Cover Bottom 145: Support Main
147: buffer member 150: case top

Claims (11)

A liquid crystal panel;
A light guide plate under the liquid crystal panel;
A plurality of optical sheets stacked on the light guide plate and transmitting heat to the liquid crystal panel, without insertion of an instrument between the light guide plate and the light guide plate;
A reflection plate in contact with a lower surface of the light guide plate;
A light source positioned on both sides of the light guide plate;
A cover bottom housing the light source and the light guide plate;
A substrate to which the light source is connected;
A plurality of heat pipes disposed on the bottom surface of the cover bottom in contact with the reflection plate and spaced apart from each other in a direction intersecting with the light source; And
And a housing which fixes the substrate to the cover bottom side and contacts the reflection plate and the heat pipe on the lower surface of the light guide plate,
The heat transferred to the heat pipe through the light source, the substrate,
Wherein the heat pipe is disposed on a lower side of the heat pipe and is exposed through a cover bottom in contact with the lower surface of the heat pipe and is connected to the reflector on the upper surface of the heat pipe, And the liquid crystal panel is dispersed and transferred to the liquid crystal panel. The method according to claim 1,
Wherein the plurality of heat pipes are spaced at equal intervals. The method according to claim 1,
And the plurality of heat pipes are disposed in an area adjacent to the light source. The method according to claim 1,
The heat pipe includes first and second capillaries which are opposed to each other, a shell between the first and second capillaries, a vapor layer, and a shell that surrounds the outer periphery of the first and second capillaries and blocks the inner vapor layer And the liquid crystal display device. The method according to claim 1,
Wherein the heat pipe is a plate. The method according to claim 1,
Wherein the heat pipe is in contact with the cover bottom with an adhesive layer interposed therebetween. The method according to claim 1,
And the heat pipe is mechanically fastened to the cover bottom. The method according to claim 1,
Wherein the light source is a light emitting diode (LED). delete delete delete

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