JP2012155237A - Side edge light type liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a side edge light type liquid crystal display device which enhances heat dissipation efficiency of heat generated by LEDs by effectively utilizing a rear frame and columns of a stand, and thereby suppresses a decrease in light emission efficiency and a decrease in luminance due to thermal deterioration of the LEDs.SOLUTION: The side edge light type liquid crystal display device is characterized in that: a liquid crystal display panel is arranged on the front side of a light guide plate 2 stored in a thermally conductive rear frame 1; LED bars 3 each having LEDs 3b mounted on a thin and long thermally conductive wiring board 3a are arranged between right and left side faces of the light guide plate 2 and right and left side plates 1a of the rear frame 1; the wiring boards 3a of the LED bars 3 are fixed in contact with inner surfaces of the right and left side plates 1a of the rear frame 1; and right and left thermally conductive columns 4a of a stand 4 are fixed in contact with outer surfaces of both the right and left side parts of the rear frame 1. Heat dissipation efficiency is improved by conducting heat generated by the LEDs 3b to both a back plate 1b of the rear frame 1 and the columns 4a of the stand 4 and then dissipating the heat.

Description

  The present invention relates to a side edge light type liquid crystal display device using LEDs (light emitting diodes), and more particularly to a liquid crystal display device devised so as to efficiently dissipate heat emitted from LEDs.

  A conventional side edge light type liquid crystal display device using a conventional LED has a rear frame 1 as shown in FIG. 3 (a rear view showing a partially broken conventional side edge light type liquid crystal display device). Between the left and right side surfaces of the light guide plate 2 housed in the left and right side plates 1a and 1a of the rear frame 1, LED bars 3 (a plurality of LEDs 3b mounted on an elongated wiring board 3a) are disposed, Light emitted from the LED 3b is incident on the light guide plate 2 from the left and right side surfaces to cause the light guide plate 2 to emit light, and behind the liquid crystal display panel (not shown in FIG. 3) disposed on the front side of the light guide plate 2 It is comprised so that light may be irradiated from. Then, the wiring board 3a of the LED bar 3 is fixed in contact with the left and right side plates 1a, 1a of the rear frame 1, and the heat generated from the LED 3b is conducted to the left and right side plates 1a, 1a of the rear frame 1 through the wiring board 3a. Further, as indicated by an arrow X in FIG. 4, heat is dissipated while being conducted toward an intermediate portion of the back plate 1 b of the rear frame 1.

  On the other hand, there is known an image display device in which a column that rises from a pedestal is arranged so as to contact a heat generating unit including a plasma display panel, a chassis, and a circuit board, and the column is actively used as a cooling member (patent) Reference 1).

  Also, in a side edge light type liquid crystal display device using LEDs, the area of the substrate on which the LEDs are mounted is made larger than the area of the light incident surface of the light guide plate to improve heat dissipation (patent) Document 2) and those in which a substrate on which an LED is mounted are brought into contact with a side surface covering member of a light guide plate to improve heat dissipation (Patent Document 3) are also known.

JP 2010-14957 A JP 2008-298905 A JP 2008-166200 A

  However, in the conventional side edge light type liquid crystal display device shown in FIG. 3, the heat generated from the LED 3b is radiated from the left and right side portions of the rear frame 1, that is, the left and right side portions of the left and right side plates 1a and 1a and the back plate 1b. The two struts 4a and 4a of the stand 4 are fixed to the central portion of the back plate 1b of the rear frame 1 and do not substantially contribute to heat dissipation, so it is difficult to say that the heat dissipation efficiency is sufficient. Therefore, the LED 3b may be thermally deteriorated in a relatively short period of time, leading to a decrease in light emission efficiency and a decrease in luminance.

  On the other hand, the image display device of Patent Document 1 uses a column rising from a pedestal portion as a cooling member, but is not a side edge light type liquid crystal display device using LEDs. It is unclear how the column is specifically used as a cooling member in the liquid crystal display device, and the display devices of Patent Documents 2 and 3 do not use the column of the stand as a heat dissipation member.

  The present invention has been made under the circumstances described above, and the problem to be solved is to effectively use the rear frame and the support column of the stand to increase the heat dissipation efficiency of the heat generated from the LED, and to accompany the thermal deterioration of the LED. It is an object of the present invention to provide a side edge light type liquid crystal display device which suppresses a decrease in luminous efficiency and a decrease in luminance.

  In order to solve the above-mentioned problems, a side edge light type liquid crystal display device according to the present invention is provided with a liquid crystal display panel on the front side of a light guide plate housed in a thermally conductive rear frame, and has an elongated thermal conductivity. The LED bar having a plurality of LEDs mounted on the wiring board is disposed between the left and right side surfaces of the light guide plate and the inner surfaces of the left and right side plates of the rear frame, and the wiring board of the LED bar is arranged on the left and right side plates of the rear frame. The left and right heat conductive columns of the stand are fixed in contact with the outer surfaces of the left and right sides of the rear frame.

  In the side edge light type liquid crystal display device of the present invention, it is preferable that the left and right columns of the stand are fixed in contact with the outer surfaces of the left and right side plates of the rear frame. And it is preferable to fix together the wiring board of a LED bar, the side plate of a rear frame, and the support | pillar of a stand with screws. Further, it is preferable that the upper ends of the left and right support columns of the stand and the upper end of the rear frame are the same height, or the upper ends of the left and right support columns of the stand are slightly lower than the upper end of the rear frame.

  As in the side edge light type liquid crystal display device according to the present invention, the wiring board of the LED bar is fixed in contact with the inner surfaces of the left and right side plates of the rear frame, and the left and right columns of the stand are fixed to the left and right side portions of the rear frame. If the LED bar wiring board, rear frame, and stand column are all thermally conductive, the heat generated from the LED will pass through the wiring board and both the left and right sides of the rear frame. The heat is transferred from the back plate to the middle part of the rear plate of the rear frame, while the rest of the heat is transferred. Furthermore, heat is conducted through the stand column. As described above, in the liquid crystal display device of the present invention, the heat emitted from the LEDs is conducted through the two heat dissipation paths to be dissipated, so that the heat dissipation efficiency is greatly improved and the light emission efficiency is reduced due to the thermal degradation of the LEDs. A decrease in luminance can be suppressed.

  As long as the left and right sides of the rear frame can be fixed to the left and right sides of the rear frame, the stand columns can be fixed to the right and left sides of the back frame. In the case of fixing, since the conduction distance until the heat generated in the LED is conducted to the support column of the stand is the shortest, there is an advantage that the heat is quickly conducted to the support column and efficiently dissipated. Moreover, the LED bar wiring board, rear frame side plate, and stand column can be fastened and fixed together with screws, making it easy to fix the LED bar and column, reducing the number of screws for fixing and reducing costs. It is also possible to plan.

  Also, if the upper ends of the left and right support posts and the upper end of the rear frame are the same height, or the upper ends of the left and right support posts are slightly lower than the upper end of the rear frame, Since the support is in contact with the entire length in the vertical direction of the portion, the contact area of the support is increased, and the heat conduction efficiency to the support is further improved.

It is a rear view which shows a side edge light type liquid crystal display device concerning one embodiment of the present invention partially fractured. It is a rear view which shows the thermal radiation path | route of the liquid crystal display device. It is a rear view which shows the conventional side edge light type liquid crystal display device partially broken. It is a rear view which shows the heat dissipation path | route of the conventional liquid crystal display device.

  Embodiments of a side edge light type liquid crystal display device according to the present invention will be described below with reference to the drawings.

  A side edge light type liquid crystal display device 10 shown in FIGS. 1 and 2 is incorporated in a cabinet 11 such as a thin liquid crystal television. Reference numeral 1 denotes a rear frame made of sheet metal having good thermal conductivity. The rear frame 1 accommodates a light guide plate 2 made of synthetic resin having excellent transparency.

  LED bars 3 and 3 are disposed between the left and right side surfaces of the light guide plate 2 and the inner surfaces of the left and right side plates 1a and 1a of the rear frame 1, respectively. The LED bar 3 includes a plurality of LEDs (light emitting diodes) 3b that emit white light at a predetermined interval on an elongated wiring substrate 3a (single layer substrate) having thermal conductivity, and has a heat dissipation efficiency. From the viewpoint of improving, the LED bar 3 in which the LED 3b is mounted on the wiring board 3a made of metal such as aluminum having good thermal conductivity is preferably used. Each LED bar 3 makes the LED 3b face the left and right side surfaces of the light guide plate 2 leaving a slight gap, and makes the opposite surface of the wiring board 3a come into surface contact with the inner surfaces of the left and right side plates 1a and 1a of the rear frame 1. These are fixed together with screws 5 as will be described later.

A liquid crystal panel (not shown in FIG. 1) is arranged on the front side (front side) of the light guide plate 2 via an optical sheet (not shown in FIG. 1) such as a light diffusion sheet. A light reflection layer is formed on the back surface of the light guide plate 2. Therefore, when each LED 3a of the LED bar 3 emits light, the light enters the light guide plate 2 from the left and right side surfaces of the light guide plate 2, the light guide plate 2 emits light, and the light emitted from the front surface of the light guide plate 2 is the optical sheet. Since it is diffused by the (light diffusing sheet) and the liquid crystal panel is uniformly irradiated from behind, liquid crystal display without luminance unevenness is performed. At this time, light to be emitted from the back surface of the light guide plate 2 is reflected to the front surface side by the light reflection layer on the back surface, and is effectively used for illumination of the liquid crystal panel, so there is no waste.
Of course, instead of the light reflecting layer on the back surface of the light guide plate 2, a light reflecting sheet may be disposed between the back surface of the light guide plate 2 and the back plate 1 b of the rear frame 1.

  This side edge light type liquid crystal display device is different from the conventional liquid crystal display device in that the distance between the metal posts 4a, 4a having good thermal conductivity of the stand 4 is increased, and the left and right posts 4a, 4a The pillar 4a, the side plate 1a, and the wiring board 3a of the LED bar 3 are fastened and fixed together by a plurality of screws 5 in surface contact with the outer surfaces of the left and right side plates 1a, 1a of the rear frame 1. The upper end of the support column 4 a and the upper end of the rear frame 1 are the same height, or the upper end of the support column 4 a is slightly lower than the upper end of the rear frame 1.

  The support 4a and the wiring board 3a of the LED bar 3 may be individually fixed to the side plate 1a of the rear frame 1 with screws. However, as described above, the support 4a, the side plate 1a, and the wiring board 3a of the LED bar 3 are connected to the screw 5 by screws. Fastening together is preferable because the work of fixing the wiring board 3a of the LED bar 3 and the support column 4a of the stand 4 becomes easy, and there is an advantage that the number of fixing screws can be reduced and the cost can be reduced. .

  Further, as described above, the upper ends of the left and right columns 4a, 4a of the stand 4 and the upper end of the rear frame 1 are the same height, or the upper ends of the left and right columns 4a, 4a of the stand 4 are higher than the upper end of the rear frame 1. If the height is a little lower, the columns 4a and 4a are in contact with each other over almost the entire length of the left and right side plates 1a and 1a of the rear frame 1, so that the contact area of the columns 4a and 4a is large. It is preferable because there is an advantage that the heat conduction efficiency to the columns 4a, 4a is further improved.

  Like the side edge light type liquid crystal display device 10 described above, the wiring board 3a of the LED bar 3 and the left and right columns 4a, 4a of the stand 4 are brought into contact with the inner and outer surfaces of the left and right side plates 1a, 1a of the rear frame 1. When the screws 5 are fastened together, the wiring board 3a of the LED bar 3, the rear frame 1, and the support column 4a of the stand all have good thermal conductivity, so that the heat generated from the LED 3b is generated by the wiring board. 3a is conducted to the side plate 1a of the rear frame 1 and part of the heat is further conducted from the back plate 1b to the middle portion of the back plate 1b of the rear frame 1 as shown by an arrow X in FIG. On the other hand, the remaining heat is further conducted through the support column 4a of the stand as shown by the arrow Y in FIG. As described above, in the side edge light type liquid crystal display device 10 of the present embodiment, the heat emitted from the LED 3b is conducted through two heat dissipation paths, that is, the heat dissipation path indicated by the arrow X and the heat dissipation path indicated by the arrow Y. Therefore, the heat dissipation efficiency is greatly improved, and it is possible to suppress a decrease in light emission efficiency and a decrease in luminance due to thermal degradation of the LED 3b.

  The support 4a of the stand 4 may be fixed in contact with the left and right side portions of the rear frame 1, that is, the left and right side plates 1a and 1a or the left and right side portions of the back plate 1b, but the liquid crystal display device 10 of the present embodiment. When the right and left side plates 1a and 1a of the rear frame 1 are fixed in contact with the support columns 4a and 4a of the rear frame 1, the conduction distance until the heat generated by the LED 3b is transmitted to the support column 4a of the stand 4 is the shortest. Therefore, there is an advantage that heat is quickly conducted to the support column 4a and efficiently dissipated, and the wiring board 3a of the LED bar 3, the side plate 1a of the rear frame 1 and the support column 4a of the stand 4 are connected as described above. Since the screws 5 can be fastened together, the fixing work of the LED bar 3 and the column 4a is simplified, and there is an advantage that the number of fixing screws can be reduced to reduce the cost, which is preferable.

DESCRIPTION OF SYMBOLS 1 Rear frame 1a Left and right side plates of rear frame 1b Back plate of rear frame 2 Light guide plate 3 LED bar 3a LED bar wiring board 3b LED
4 Stand 4a Stand left and right support 5 Screw

In order to solve the above-mentioned problems, a side edge light type liquid crystal display device according to the present invention is provided with a liquid crystal display panel on the front side of a light guide plate housed in a thermally conductive rear frame, and has an elongated thermal conductivity. An LED bar having a plurality of LEDs mounted on the wiring board is disposed between the left and / or right side surface of the light guide plate and the inner surface of the left and / or right side plate of the rear frame. The left and / or right side plate of the rear frame is fixed in contact with the inner surface of the rear frame, and the left and right heat conductive columns of the stand are fixed in contact with the outer surfaces of the left and right sides of the rear frame. is there.

As in the side edge light type liquid crystal display device according to the present invention, the wiring board of the LED bar is fixed in contact with the inner surface of the left and / or right side plate of the rear frame, and the left and right columns of the stand are fixed to the rear frame. If the LED bar wiring board, rear frame, and stand column are all thermally conductive when they are in contact with the outer surfaces of the left and right side parts, the heat generated from the LED passes through the wiring board to the rear frame. dorsal conducted to the left and or right section min (left and or right portions of the left and or right side plates and the back plate), a part of the heat is being conducted further towards the middle portion of the back plate of the rear frame While the heat is radiated from the plate, the remaining heat is further conducted through the stand column and radiated. As described above, in the liquid crystal display device of the present invention, the heat emitted from the LEDs is conducted through the two heat dissipation paths to be dissipated, so that the heat dissipation efficiency is greatly improved and the light emission efficiency is reduced due to the thermal deterioration of the LED A decrease in luminance can be suppressed.

Claims (4)

  A liquid crystal display panel is arranged on the front side of the light guide plate housed inside the heat conductive rear frame, and LED bars each having a plurality of LEDs mounted on an elongated heat conductive wiring board are connected to the left and right side surfaces of the light guide plate. The LED bar wiring board is fixed in contact with the inner surfaces of the left and right side plates of the rear frame, and the left and right heat conductive columns of the stand are mounted on the rear. A side edge light type liquid crystal display device characterized by being fixed in contact with the outer surfaces of the left and right sides of the frame.   2. The liquid crystal display device according to claim 1, wherein the left and right columns of the stand are fixed in contact with the outer surfaces of the left and right side plates of the rear frame.   3. The liquid crystal display device according to claim 2, wherein the wiring board of the LED bar, the side plate of the rear frame, and the support column of the stand are fastened and fixed together with screws.   The upper ends of the left and right support columns of the stand and the upper end of the rear frame are the same height, or the upper ends of the left and right support columns of the stand are slightly lower than the upper end of the rear frame. The liquid crystal display device according to claim 3.

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