JP2010271661A - Liquid crystal module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal module that emits white light from a light guide plate to the back of a liquid crystal panel by use of a blue light emitting LED chip as it is, that avoids a cost increase due to increases in the number of components and the number of man days required for assembly, and that has high luminance and excellent heat dissipation. <P>SOLUTION: The liquid crystal module has the configuration described below. The light guide plate 10 is disposed on the back side of the liquid crystal panel 4, and the blue light emitting LED chip 11 is disposed on a side face of the light guide plate 10. In addition, a fluorescent coating film 15 that emits yellow fluorescence is formed on the surface of the light guide plate 10 or the light guide plate 10 contains a fluorescent material. Preferably, a reflecting metal plate 16 is disposed on the back of the light guide plate 10. A contact piece 16a is integrally formed with the reflecting metal plate, thereby disposed in contact with the LED chip 11. White light is generated by combining blue light emitted from the LED chip 11 and yellow fluorescence emitted from the fluorescent coating film 15 or fluorescent material and the white light is emitted from behind the liquid crystal panel 4. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a liquid crystal module, and more particularly to a liquid crystal module having an improved backlight provided on the back side of a liquid crystal panel.

  In a conventional liquid crystal module, a light source is disposed on the back side of the liquid crystal panel to directly illuminate the liquid crystal panel from behind, and a light guide plate is disposed on the back side of the liquid crystal panel. There is a sidelight type liquid crystal module that irradiates light from a light source arranged on a side surface to the liquid crystal panel from behind through the light guide plate.

  Many of the latter sidelight type liquid crystal modules use an LED chip as a light source for the backlight. When white light emission is required, the blue light emitting LED chip is usually covered with a phosphor that emits yellow fluorescence. A white light emitting device is used.

  On the other hand, as a planar light source used as a display backlight, a blue light emitting diode is optically connected to at least one end face of a transparent light guide plate, and white powder is applied to one of the main surfaces of the light guide plate. A transparent film is provided on the main surface of the light guide plate opposite to the scattering layer, and a fluorescent material that emits fluorescence when excited by the light emission of the blue light emitting diode is provided on the surface or inside of the film. A planar light source is known (Patent Document 1). In the planar light source, for example, when an orange fluorescent pigment is used as the fluorescent material, the emission color is white.

  In addition, a liquid crystal display device (Patent Document 2) in which a reflector made of an aluminum plate with an acrylic white reflective coating is disposed on the lower surface side of the light guide plate, or a cold cathode tube is disposed on the side surface of the light guide plate, aluminum There is also known a liquid crystal display device (Patent Document 3) in which a heat radiating sheet is provided in contact with the lower surface of the light guide plate in the vicinity of the cold cathode tube.

JP-A-8-7614 Japanese Patent Laid-Open No. 6-51310 JP-A-9-318940

  However, as in the past, when using an LED chip that emits white light by covering a blue light emitting LED chip with a yellow light emitting LED chip, the cost is high, so the blue light emitting LED chip is used as it is. Therefore, it is desired to improve the backlight of the liquid crystal module so as to emit white light.

  The planar light source disclosed in Patent Document 1 meets the above-described demand, but includes a fluorescent material that is excited by light emission of a blue light-emitting diode on the surface of the light guide plate opposite to the surface on which the scattering layer is formed. Since the film is provided, the number of parts and the number of assembling steps are increased, and there is a problem that the cost is increased.

  Further, the liquid crystal display device of Patent Document 2 is expensive because it uses an aluminum plate with an acrylic white reflective coating on the surface of the aluminum plate, and the liquid crystal display device of Patent Document 3 is a light guide plate. There is a problem that the heat radiation effect is not sufficient because the heat radiation sheet is provided only on the lower surface near the cold cathode tube.

  The present invention has been made under the circumstances described above, and the problem to be solved is that a blue light emitting LED chip can be used as it is to irradiate the back surface of the liquid crystal panel with white light emission from the light guide plate. An object of the present invention is to provide a liquid crystal module having high brightness and excellent heat dissipation, which does not cause an increase in cost due to an increase in the number of assembly steps.

  In order to solve the above problems, a liquid crystal module according to a first aspect of the present invention is a liquid crystal module in which a light guide plate is disposed on the back side of a liquid crystal panel and a light source is disposed on a side surface of the light guide plate. And a fluorescent coating film that emits yellow fluorescence is formed on the surface of the light guide plate.

  The liquid crystal module according to the second aspect of the invention is a liquid crystal module in which a light guide plate is disposed on the back side of the liquid crystal panel and a light source is disposed on a side surface of the light guide plate. The light guide plate includes a fluorescent material that emits yellow fluorescence.

  In the liquid crystal module according to the first and second inventions, it is desirable to dispose a metal reflector on the entire back surface of the light guide plate. Further, a contact piece is integrally formed on the metal reflector and the contact piece is connected to the LED. It is desirable to contact the chip.

  Like the liquid crystal module according to the first invention, when the LED chip emitting blue light is disposed on the side surface of the light guide plate and the fluorescent coating film that emits yellow fluorescence is formed on the surface of the light guide plate, When the emitted blue light is emitted from the surface of the light guide plate, the blue light and the yellow fluorescent light emitted from the fluorescent coating on the surface of the light guide plate are combined into white light, which is irradiated onto the liquid crystal panel from behind. The

  In addition, as in the liquid crystal module according to the second aspect of the invention, when a blue light emitting LED chip is disposed on the side surface of the light guide plate and the fluorescent material emitting yellow fluorescence is contained in the light guide plate, the light guide plate is led from the LED chip. The blue light incident on the light plate and the yellow fluorescent light emitted from the fluorescent material in the light guide plate are combined into white light, and the liquid crystal panel is irradiated from the surface of the light guide plate.

  Thus, since the liquid crystal modules according to the first and second inventions use the blue light emitting LED chip as they are, the cost of the LED chip is lower than that of the conventional white light emitting LED chip, Since there is no need to provide a film containing a fluorescent material on the light guide plate as in Patent Document 1, the cost is not increased due to an increase in the number of parts and the number of assembly steps, and the overall cost is reduced. Is possible.

  In the liquid crystal module according to the first and second inventions, the metal reflector is disposed on the entire back surface of the light guide plate. The blue light incident on the light guide plate from the LED chip is the metal reflector on the back surface of the light guide plate. And when almost all of the blue light is transmitted through the fluorescent coating on the surface of the light guide plate without waste, it is combined with white light and applied to the liquid crystal panel, or the blue light incident on the light guide plate from the LED chip and The synthetic white light with the yellow fluorescent light emitted from the fluorescent material in the light guide plate is reflected by the metal reflector on the back of the light guide plate, and almost all of the synthetic white light is emitted from the light guide plate surface to the liquid crystal panel without waste. The brightness of the liquid crystal panel is improved. Further, the metal reflector is inexpensive because it does not have an acrylic white reflective coating on the surface.

  Further, in the above liquid crystal module, when the contact piece is integrally formed on the metal reflector and the contact piece is brought into contact with the LED chip, the heat generated by the LED chip passes through the contact piece, and the entire back surface of the light guide plate. Since the heat is conducted to the metal reflector disposed on the surface of the metal reflector and efficiently radiated from the entire surface of the metal reflector, there is no risk of overheating in the vicinity of the LED chip.

It is a disassembled perspective view which shows one Embodiment of the liquid crystal module which concerns on 1st invention. It is a partial expansion perspective view which abbreviate | omits the flexible wiring board for LED and shows the backlight unit integrated in the liquid crystal module. It is a partial expanded sectional view of the same backlight unit. It is a partial expanded sectional view of the backlight unit integrated in the liquid crystal module concerning a 2nd invention.

The liquid crystal module of the first invention shown in exploded form in FIG. 1 is a small-sized liquid crystal module in which a sidelight type backlight unit BLU is incorporated, and includes a rear frame 1, a backlight unit BLU, optical sheets 2, 3, It is composed of main parts such as the liquid crystal panel 4 and the bezel 5 and other various parts.
In FIG. 1, in order to make the configuration of the backlight unit BLU easier to understand, the LED flexible printed wiring board 13 of the backlight unit BLU is drawn separately from the LED chip 11, but as described later, The LED flexible printed wiring board 13 is previously overlapped with the LED chip 11 and connected with a conductive adhesive.

  An outline of the overall configuration of the liquid crystal module is as follows. The rear frame 1 is injection-molded in a rectangular frame shape with a white synthetic resin, and a backlight unit support portion 1a is formed on the inner periphery thereof. The backlight unit BLU is fitted in the rear frame 1 and supported by the support portion 1a. The backlight unit BLU will be described in detail later.

  On the upper side (light emission surface side) of the backlight unit BLU, a liquid crystal panel 4 is disposed with one light diffusion sheet 2 and two prism sheets 3 and 3 interposed as optical sheets. It is fitted in the frame 1. Then, a rectangular frame-shaped metal bezel 5 is fitted to the rear frame 1 from above the liquid crystal panel 4, and the respective engaging claws 1 b formed on the frame 1 are respectively engaged with the bezel 5. It is integrally assembled so as not to be separated by engaging with the joint 5a. A main flexible printed wiring board 6 is connected to the liquid crystal panel 4, and the flexible printed wiring board 6 and the flexible printed wiring board for LED 13 have one side when the bezel 5 is fitted to the frame 1. Are drawn out from the two outlets (two outlets formed on one side of the backlight unit BLU on the LED chip arrangement side).

  In FIG. 1, 7a and 7b are spacers inserted between the upper prism sheet 3 and the liquid crystal panel 4, 8 is a masking tape inserted between the liquid crystal panel 4 and the bezel 5, and 9 is a liquid crystal panel. 4 is an insulating tape that covers a connection portion between the main flexible printed wiring board 6 and the main flexible printed wiring board 6.

  This liquid crystal module has a great feature in the sidelight type backlight unit BLU arranged on the back side (lower side in FIG. 1) of the liquid crystal panel 4. That is, as shown in FIGS. 1 to 3, the backlight unit BLU has a plurality of blue light emitting LED chips 11 as light sources on the side surface of the light guide plate 10 made of synthetic resin having excellent transparency (this embodiment And three LED chips 11 are connected to the flexible printed wiring board 13 for LED stacked thereon by a conductive adhesive 14 or the like. A fluorescent coating film 15 that is excited by blue light emitted from the LED chip 11 to emit yellow fluorescence is applied and formed on the surface (light emitting surface) of the light guide plate 10.

  In addition, a metal reflector 16 also serving as a heat sink made of an aluminum plate or the like is disposed on the entire back surface of the light guide plate 10, and an LED chip is formed from one side of the metal reflector 16 (one side on the LED chip arrangement side). A plurality of contact pieces 16 a are provided so as to correspond to 11. These contact pieces 16a are in contact with the lower surface of the LED chip 11 and support the LED chip 11 from below.

  In the liquid crystal module in which the backlight unit BLU is incorporated on the back side of the liquid crystal panel 4, the blue light incident on the light guide plate 10 from the LED chip 11 is reflected by the metal reflector 16 on the back side of the light guide plate 10. Thus, almost all of the blue light passes through the fluorescent coating 15 on the surface of the light guide plate 10 without waste, and is then combined with yellow fluorescence emitted from the fluorescent coating 15 to become white light. It will be irradiated from behind. As described above, almost all of the blue light incident on the light guide plate 10 from the LED chip 11 is synthesized into white light without waste and is applied to the liquid crystal panel 4, so that the brightness of the liquid crystal panel 4 is improved and the display is bright and clear. Liquid crystal display can be performed. Moreover, since the liquid crystal module uses the blue light emitting LED chip 11 as it is, the cost of the LED chip is lower than that of the conventional white light emitting LED chip, and the fluorescent coating 15 is formed on the surface of the light guide plate 10. Therefore, it becomes unnecessary to provide a film having a fluorescent material on the light guide plate as in Patent Document 1, and the cost is not increased due to an increase in the number of parts and the number of assembling steps, so that the cost can be reduced as a whole. It becomes. Furthermore, the heat generated in the LED chip 11 is conducted through the contact piece 16a to the metal reflecting plate 16 disposed on the entire back surface of the light guide plate 10, and is efficiently radiated from the entire surface of the metal reflecting plate 16, so that the LED chip 11 The worry of overheating the vicinity of is also eliminated.

  FIG. 4 is a partial enlarged cross-sectional view of a backlight unit BLU incorporated in the liquid crystal module according to the second invention. This backlight unit BLU is replaced with the light guide plate 10 having a fluorescent coating film formed on the surface thereof. The configuration is the same as that of the backlight unit BLU shown in FIG. 3 except that the light guide plate 17 containing a fluorescent material emitting yellow fluorescence in a uniform dispersed state is used.

  In the liquid crystal module of the second invention in which the backlight unit BLU as described above is incorporated on the back side of the liquid crystal panel 4, the light emitted from the blue light incident on the light guide plate 17 from the LED chip 11 and the fluorescent material in the light guide plate 17. The synthetic white light with the yellow fluorescent light is reflected by the metal reflector 16 on the back surface of the light guide plate 17 and almost all of the synthetic white light is irradiated to the liquid crystal panel 4 from the surface of the light guide plate 17 without waste. Will improve. And this liquid crystal module also uses the blue light emitting LED chip 11 as it is, so the parts cost is low, and since the fluorescent material is contained in the light guide plate 17, there is no cost increase due to an increase in the number of parts and assembly man-hours, Moreover, since the heat emitted from the LED chip 11 is dissipated from the metal reflector 16, there is no fear of overheating.

DESCRIPTION OF SYMBOLS 1 Rear frame 2,3 Optical sheet 4 Liquid crystal panel 5 Bezel 10, 17 Light guide plate 11 Blue light emitting LED chip 13 Flexible printed wiring board for LED 15 Fluorescent coating film 16 Metal reflector 16a Contact piece BLU backlight unit

Claims (4)

In the liquid crystal module in which the light guide plate is arranged on the back side of the liquid crystal panel and the light source is arranged on the side surface of the light guide plate,
A liquid crystal module comprising: a blue light emitting LED chip as the light source; and a fluorescent coating film that emits yellow fluorescence on the surface of the light guide plate. In the liquid crystal module in which the light guide plate is arranged on the back side of the liquid crystal panel and the light source is arranged on the side surface of the light guide plate,
A liquid crystal module comprising: a blue light emitting LED chip as the light source; and the light guide plate containing a fluorescent material that emits yellow fluorescence.   The liquid crystal module according to claim 1, wherein a metal reflector is disposed on the entire back surface of the light guide plate.   4. The liquid crystal module according to claim 3, wherein a contact piece is integrally formed on the metal reflector, and the contact piece is brought into contact with the LED chip.

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