JP2007322595A - Liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reliably secure the light sources at the predetermined locations over a long period when mounting the light sources of the back light on a flexible circuit board connected to the liquid crystal display panel and positioning them to the side of the light guide plate via the flexible board. <P>SOLUTION: A liquid crystal display has: a liquid crystal display panel 10 having a terminal 11a; a back light 20 accommodating an illuminating means including a light guide plate 22 and light sources 23 positioned on its side in a holder case 21a, and disposed on the surface back of the viewing surface of the liquid crystal display panel 10; and a flexible circuit board 30 whose one end 30a is connected to the terminal 11a and the other end 30b is folded toward the back light 20. The other end 30b of the flexible circuit board 30 is folded back between the terminal 11a and the holder case 21a, and the light source 23 are mounted on the folded end 30b in the predetermined positions facing the side of the light guide plate 22. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a liquid crystal display device having a backlight for irradiating light to the liquid crystal display panel, and more particularly to a liquid crystal display device in which a light source of a backlight is mounted on a flexible substrate connected to the liquid crystal display panel. It is.

  Since the liquid crystal display panel is a passive component, a terminal portion is provided on at least one side, and a flexible substrate that supplies a display drive signal is connected to the terminal portion. In addition, a transmissive or transflective liquid crystal display panel includes a backlight so that a bright display can be obtained even in a dark environment.

  In a liquid crystal display device having this type of backlight, when processing the flexible substrate at the time of assembly, for example, as described in Patent Document 1, the flexible substrate is folded back to the back side of the backlight, and a double-sided adhesive tape or the like is used. It is fixed to the backlight case.

  An example of this will be described with reference to FIG. FIG. 3 is a schematic cross-sectional view showing an enlarged part of a liquid crystal display device in which a sidelight-type backlight 20 is arranged on the side opposite to the observation surface (back side) of the liquid crystal display panel 10.

  The liquid crystal display panel 10 is a laminated body in which a first transparent electrode substrate 11 on the front side and a second transparent electrode substrate 12 on the rear side are bonded together via a peripheral sealing material (not shown). Has been. Further, polarizing plates 13 and 13 are attached to the outer surfaces of the transparent electrode substrates 11 and 12.

  In this example, the terminal part 11a is connected to the first transparent electrode substrate 11 on the front side so as to protrude sideways, and one end of the flexible substrate 30 is connected to the terminal part 11a. In many cases, the flexible substrate 30 uses a TCP (Tape Carrier Package) or a COF (Chip On Film) on which a chip component 31 for display driving is mounted.

  The backlight 20 includes a holder case 21 having a surface facing the second transparent electrode substrate 12 on the rear side, and a light guide plate 22 made of, for example, acrylic resin is accommodated in the holder case 21. Since it is a side light type, a light source 23 is disposed in the holder case 21 on the side of the light guide plate 22. Usually, since a light emitting diode is used for the light source 23, the light source may be referred to as the light emitting diode 23 in the following description.

  The number of the light emitting diodes 23 is determined according to the amount of light required, and is disposed on the side of the light guide plate 22 in a state of being mounted on another backlight substrate having power supply wiring. Then, in order to reduce the number of parts and assembly man-hours by sharing the board, the following is performed.

  That is, the light emitting diode 23 is mounted on the flexible substrate 30 by including the power supply wiring, and the light emitting diode 23 is attached to the light guide plate 22 from the lower surface side of the holder case 21 as the flexible substrate 30 is folded back to the back surface side of the backlight 20. It arrange | positions to a side and fixes the flexible substrate 30 to the lower surface of the holder case 21 with the double-sided adhesive tape T. FIG.

JP 2002-258317 A

  However, since the flexible substrate 30 is bent by about 180 ° when viewed from the terminal portion 11a of the liquid crystal display panel 10, the restoring force is always applied to the double-sided adhesive tape T. In addition, the adhesive strength of the double-sided adhesive tape T deteriorates not only with time but also with temperature and humidity.

  Therefore, the double-sided adhesive tape T cannot withstand the restoring force of the flexible substrate 30, and the flexible substrate 30 floats up from the holder case 21 in the direction of the arrow in FIG. 3, and accordingly, the optical axis of the light emitting diode 23 is shifted and uneven light emission occurs. Sometimes. Further, in the case of in-vehicle use, since vibration is further applied, in the worst case, the flexible substrate 30 may be completely peeled from the holder case 21.

  To prevent this, for example, the flexible substrate 30 may be screwed to the holder case 21. However, since the holder case 21 is molded with a minimum necessary thickness in order to reduce the thickness and weight, the female case 30 is female. It is difficult to form a screw hole. Further, even if the female screw hole can be formed, the light emitting diode 23 may be staggered if it is stopped at one point, so it is necessary to stop it at several points, which is not preferable from the viewpoint of assembly workability.

  Accordingly, an object of the present invention is to provide a long-term operation when a light source of a backlight is mounted on a flexible substrate connected to a liquid crystal display panel, and the light source is disposed at a side position of the light guide plate of the backlight via the flexible substrate. In other words, the light source can be securely fixed at an intended position.

  In order to solve the above-mentioned problem, the invention according to claim 1 is a lighting device including a liquid crystal display panel having a terminal portion on at least one side, a light guide plate in a holder case, and a light source disposed on the side thereof. In a liquid crystal display device comprising a backlight housed and disposed on the side opposite to the observation surface of the liquid crystal display panel, and a flexible substrate having one end connected to the terminal portion and the other end folded back to the backlight side The other end of the flexible substrate is folded between the terminal portion and the holder case, and the light source is disposed on a side of the light guide plate in the holder case at a predetermined portion on the folded other end side. It is characterized by being implemented as follows.

  According to a first aspect of the present invention, in the first aspect, a chip component for display driving is mounted adjacent to the light source on the other end side of the flexible substrate, and the chip component is mounted together with the light source on the holder case. It is characterized by being housed inside.

  According to the first aspect of the present invention, the other end of the flexible substrate whose one end is connected to the terminal portion of the liquid crystal display panel is folded back between the terminal portion and the holder case, thereby restoring the flexible substrate. The force is received by the holder case, and the other end of the flexible substrate is always kept in pressure contact with the holder case. Therefore, by mounting the light source on the folded portion of the flexible substrate and arranging the light source on the side of the light guide plate in the holder case, the light source can be reliably fixed at an intended position for a long period of time.

  According to the second aspect of the present invention, the display driving chip component is mounted in the holder case together with the light source by mounting the display driving chip component adjacent to the light source on the folded portion of the flexible substrate. Therefore, the size and thickness can be further reduced.

  Next, an embodiment of the present invention will be described with reference to FIGS. 1 and 2, but the present invention is not limited to this. FIG. 1 is an enlarged schematic sectional view showing a part of a liquid crystal display device according to the present invention, and FIG. 2 is a perspective view showing a part of a holder case of a backlight. Note that the same reference numerals are used for components that do not need to be changed from the conventional example described in FIG.

  As shown in FIG. 1, this liquid crystal display device includes a liquid crystal display panel 10 and a sidelight type backlight 20. The liquid crystal display panel 10 is the same as the conventional example described in FIG. Similarly, a liquid crystal substance is sealed between the first transparent electrode substrate 11 on the front side and the second transparent electrode substrate 12 on the rear side, which are bonded to each other via a peripheral sealing material (not shown), and each transparent electrode substrate 11 is sealed. , 12 may be a liquid crystal display panel having polarizing plates 13, 13 attached to the outer surface thereof.

  Also in this embodiment, the terminal portion 11a is connected to the front first transparent electrode substrate 11 so as to protrude laterally, and the TCP 11 in which the chip component 31 for display driving is mounted on the terminal portion 11a. One end 30a of a flexible board 30 such as COF or COF is connected. In addition, a terminal part may be provided in the 2nd transparent electrode substrate 12 of a rear side, and such an aspect is also included in this invention.

  The backlight 20 includes a holder case 21a in which illumination means for the liquid crystal display panel 10 is housed. The holder case 21a in this embodiment is a surface facing the rear second transparent electrode substrate 12, 3 is different from the holder case 21 of the conventional example described in FIG. 3 in that the side portion of the light guide plate 22 is also opened.

  In this holder case 21a, a light guide plate 22 made of, for example, acrylic resin is accommodated at a position facing the second transparent electrode substrate 12 on the rear side, and the remaining light guide plate 22 side as shown in FIG. The side portion is a component storage portion S whose upper surface is opened. In this component storage portion S, a light emitting diode 23 as a light source is preferably stored together with a chip component 31 for display driving.

  In the present invention, the other end 30b of the flexible substrate 30 is folded not between the bottom surface side of the holder case 21a but between the terminal portion 11a of the liquid crystal display panel 10 and the holder case 21a. At this time, the component housing portion S is covered with the other end 30 b side of the flexible substrate 30, and the other end 30 b side is received by the side frame of the holder case 21 a and / or the end portion of the light guide plate 22.

  Accordingly, the restoring force of the flexible substrate 30 holds the other end 30b side in a stable state in pressure contact with the holder case 21a. Therefore, as shown in FIG. 1, the light emitting diode 23 is mounted on the folded other end 30 b side of the flexible substrate 30, stored in the component storage portion S, and disposed on the side of the light guide plate 22. It is possible to reliably fix the light emitting diode 23 at an intended position over a period.

  Further, when there is a margin in the component storage portion S, as shown in FIG. 1, the display driving chip component 31 is mounted adjacent to the light emitting diode 23 on the side of the other end 30 b of the flexible substrate 30 that is folded back. Then, by storing the chip component 31 together with the light emitting diode 23 in the component storage portion S, compared to the case where the chip component 31 is arranged on the bottom surface side of the holder case 21 in the conventional example described in FIG. The thickness of the device can be reduced.

  In the above embodiment, as shown in FIG. 2, the entire upper surface of the component storage unit S is opened. However, as another embodiment, a top plate is provided in the component storage unit S, and the top plate emits light. A hole through which the diode 23 and the chip component 31 can pass may be formed. In this case, the width of the flexible substrate 30 on the other end 30b side may be narrower than the component storage portion S.

  Alternatively, the other end 30b of the flexible substrate 30 may be fixed to the holder case 21a with a double-sided adhesive tape or the like. The liquid crystal display panel 10 may be either STN type or thin film transistor (TFT) type.

FIG. 2 is a schematic cross-sectional view showing an enlarged part of a liquid crystal display device according to the present invention. The perspective view which shows a part of backlight holder case in the said liquid crystal display device. FIG. 10 is a schematic cross-sectional view showing an enlarged part of a conventional liquid crystal display device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Liquid crystal display panel 11,12 Transparent electrode substrate 11a Terminal part 20 Backlight 21a Holder case 22 Light guide plate 23 Light emitting diode (light source)
DESCRIPTION OF SYMBOLS 30 Flexible substrate 30a One end of a flexible substrate 30b The other end of a flexible substrate 31 Chip components

Claims (2)

Illumination means including a liquid crystal display panel having a terminal portion on at least one side and a light guide plate and a light source disposed on the side of the light guide plate is accommodated in the holder case, and is disposed on the side opposite to the observation surface of the liquid crystal display panel. In a liquid crystal display device comprising a backlight and a flexible substrate having one end connected to the terminal portion and the other end folded back to the backlight side,
The other end of the flexible substrate is folded between the terminal portion and the holder case, and the light source is disposed on a side of the light guide plate in the holder case at a predetermined portion on the folded other end side. The liquid crystal display device is mounted as described above. 2. The display drive chip component is mounted on the other end side of the flexible substrate adjacent to the light source, and the chip component is housed in the holder case together with the light source. Liquid crystal display device.

Images