JP3748908B2 - Liquid crystal display - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a liquid crystal display, and more particularly to a liquid crystal display in which a light source is disposed on a side surface of a light guide plate .
[0002]
[Prior art]
Conventionally, in a liquid crystal display device, as disclosed in Japanese Patent Laid-Open No. 5-72514, a liquid crystal cell and a lighting device including a light guide plate and a light source disposed below the liquid crystal cell are used using a metal frame. It was supported and housed to form a so-called module. In many of these modules, the illuminating device and the liquid crystal cell can be handled independently by separately accommodating the illuminating device in a resin frame and placing the liquid crystal cell on the frame and storing it in a metal frame. .
[0003]
However, liquid crystals and light guide plates have a relatively long life, but light sources have a much shorter life and higher failure rate than liquid crystal cells, so they must be replaced according to the appropriate elapsed time of use. Since both the frame and the resin frame must be disassembled, the replacement workability is poor, and if dust enters during the replacement work, the display quality will be lowered.
[0004]
[Problems to be solved by the invention]
The present invention has been made in consideration of the above points, and has as its main object to improve the light source replacement workability, and also to satisfactorily dissipate heat generated from the light source.
[0005]
[Means for Solving the Problems]
The present invention includes a light source, a reflector disposed so as to surround the light source, a printed circuit board on which lead wires of the light source are printed and wired, and a support member in which the light source, the reflector, and the printed circuit board are fixedly disposed. A light source unit is configured, and the light source unit is housed in a frame having a downwardly opened space for detachably disposing from the back side of the frame to the side of the light guide plate, and the light source unit positioned and arranged in the space The liquid crystal display device is fixed from the back side with a fixing angle.
[0006]
According to the present invention, the light guide plate has a heat radiating plate on the back surface, the reflecting plate has good thermal conductivity, and the reflecting plate is in contact with the back surface of the heat radiating plate.
[0007]
[0008]
[0009]
[0010]
[Action]
According to the present invention, a light source unit is constituted by the light source, the reflection plate arranged so as to surround the light source, and the support member on which the light source and the reflection plate are fixedly arranged, and the light source unit can be attached to and detached from the frame body. As a result, the replacement work of the light source becomes extremely easy.
[0011]
Further, since the frame has a structure having a space for detachably arranging the light source unit from the back side of the frame to the side of the light guide plate, and a fixing means for fixing the light source unit positioned in this space, The light source unit can be attached and detached from the back side of the frame, and the light source replacement workability is improved even when the lighting device is thinned or when various parts are arranged on the side surface and it is difficult to replace it from the side surface direction. Can keep good. Furthermore, since the display surface side is not released, it is possible to prevent dust from entering between the display and the light guide plate.
[0012]
Moreover, since the light source unit has the printed circuit board on which the lead wire of the light source is wired and fixed to the support member, the lead wire is not loosened, and the light source unit can be easily replaced. Furthermore, since there is no positional deviation between the light source and its lead wire, it is possible to prevent the light source from becoming unstable due to impedance mismatch.
[0013]
In addition, since the reflector of the light source unit is a member with good thermal conductivity and is in contact with the heat sink on the back of the light guide plate, the heat generated from the light source can be dissipated from the back side, and the display on the front side It is possible to suppress uneven heat effects on the vessel.
[0014]
[0015]
【Example】
1 and 2 are exploded sectional views of the principal part of a liquid crystal display device provided with the illumination device of the embodiment of the present invention, and FIG. 3 is a sectional view of the principal part of the liquid crystal display device. 4 is a cross-sectional view of the light source unit, FIG. 5 is a front view of the main part of the light source unit, FIG. 6 is a rear view of the main part of the light source unit, and FIG. In the figure, reference numeral 1 denotes a twisted nematic type or super twisted nematic type liquid crystal display (hereinafter referred to as a liquid crystal cell) that is sandwiched between two substrates 11 and has a polarizing plate 12, for example. The substrate 13 is connected, and the driving element is, for example, of the tape automated bonding (TAB) type in which the semiconductor element is fixed to the flexible substrate 14. An elastic cushioning material 15 may be disposed under the liquid crystal cell 1 as necessary.
[0016]
A lighting device 2 is disposed below the liquid crystal cell 1. The illumination device 2 accommodates the light guide plate 3 disposed along the back surface of the liquid crystal cell 1, the light source unit 4 that irradiates light to the side surface of the light guide plate 3, and the light guide plate 3 and the light source unit 4. For example, a resin frame 5 is provided. The light guide plate 3 is made of a light conductive flat plate made of an acrylic resin or the like in which a light diffusing plate 31 is disposed on the surface and a reflective sheet 32 and a heat radiating plate 33 made of an aluminum thin plate having a good thermal conductivity are disposed on the bottom surface. The light source unit 4 includes a linear light source 41 composed of a cold-cathode tube or a fluorescent lamp driven at high frequency, and a metal having high heat conductivity and strength arranged so as to surround the light source 41 with a C-shaped cross section. Preferably, the reflector 42 made of aluminum having a wall thickness of 0.2 mm or more, a support member 43 made of a resin molded product, a printed board 44 in which the lead wires of the light source 41 are printed and wired, and heat-resistant flexibility For example, a ring-shaped spacer 45 made of silicon rubber is used. The frame 5 may be constituted by an upper frame 51 having a substantially square shape in plan view for supporting the light guide plate 3, but an upper frame 51 and a bottom frame (not shown) provided with mutual locking means as required. Or the like.
[0017]
Next, the light source unit 4 will be described in detail with reference to FIGS. Cylindrical light source terminal receiving portions 431 that receive both ends of the light source 41 are integrally provided at both ends of the support member 43. The light source terminal receiving portion 431 is elastically biased toward the light source terminal side, for example, in the same manner as the both-end holding mechanism generally used in a direct type fluorescent lamp, so that the light source 41 can be easily replaced. A terminal connection structure can be incorporated.
[0018]
When it is not necessary to remove the light source 41 from the light source unit 4, both ends of the light source 41 may be integrally fixed to the light source terminal receiving portion 431, or the support member 43 may be provided without providing the light source terminal receiving portion 431. It may be fixed directly.
[0019]
In order to form an appropriate distance between the light guide plate 3 and the reflection plate 42, a plurality of the ring-shaped spacers 45 are arranged at appropriate positions on the outer surface of the light source 41. The reflection plate 42 is disposed so as to be positioned between the light source terminal receiving portions 431 and is fixed to the upper surface side of the support member 43, and a silver vapor deposition process for increasing the reflection efficiency is performed on the reflection surface facing the light source 41. A reflecting member surrounding the light source 41 is formed together with a reflecting sheet 53 described later.
[0020]
The printed circuit board 44 is fixed to the lower surface side of the support member 43 in order to keep the distance between the wide lead wire printed and wired and the light source 41 constant, and the light source terminal receiving portion 431 is electrically connected to the light source terminal receiving portion 431 by a short lead wire 432. Connections are made. In this way, the lead wire of the light source 41 is widened and wired to the printed circuit board 44, and the printed circuit board 44 and the light source 41 are integrated and positioned by the support member. Therefore, when the light source 41 is driven at a high frequency, the lead wire Impedance mismatch due to the positional deviation of the light source 41 can be prevented, and the lighting state of the light source 41 can be stabilized. Further, the support member 43 has a locking hole 433 for receiving a locking claw 71 of a unit fixing angle 7 to be described later and a locking claw for receiving a lower end portion of the printed circuit board 13 for use in positioning and fixing the light source unit 4. 434 is formed.
[0021]
The frame body 5 that supports the liquid crystal cell 1 and houses the illumination elements has a space 52 opened downward at a side position of the light guide plate 3 in order to detach the light source unit 4 from the back side of the frame body 5. Yes. Further, the upper frame 51 is configured to be positioned between the liquid crystal cell 1 and the light guide plate 3, and transmits light emitted from the surface of the light guide plate 3 to substantially the center so as to guide at least the effective display surface of the liquid crystal cell 1. It has a hole. On the back surface of the upper frame 51 positioned above the space 52, the reflective sheet 53 is bonded to an adhesive member such as an adhesive or a double-sided tape over a range connecting the upper edge of the side surface of the light guide plate 3 and the upper edge of the reflective plate 42 in the mounted state. The light source 41 excluding the side surface of the light guide plate 3 is surrounded by the reflection sheet 53 and the reflection plate 42. As described above, the reflection sheet 53 as the first reflection member in which the reflection member surrounding the light source 41 is fixed to the frame 5 and the reflection plate 42 as the second reflection member fixed to the removable light source unit 4. Since the structure is separable, the light source unit 4 can be easily attached and detached while maintaining the reflection efficiency, and when the light source unit 4 is mounted, the gap that may occur between the reflector 42 and the light guide plate 3 is reflected. The sheet 53 can be reliably closed.
[0022]
6 is a metal frame having a substantially rectangular surface that covers the liquid crystal cell 1 and has a through hole 61 provided so that a liquid crystal display can be observed at a substantially central portion of the surface. Has a fixing means (not shown) for locking to the bottom frame of the frame body 5 and an L-shaped notch 62 as shown in FIGS. In addition to these fixing means, screws or the like may be further used as fixing auxiliary means for the frame 5 or the metal frame 6.
[0023]
7 is a fixing means for fixing the light source unit 4 disposed in the space 52 of the frame body 5 and a unit fixing angle having a substantially L-shaped cross section that also serves as a part of the bottom frame of the frame body 5. A locking claw 71 to be inserted into the locking hole 433 is formed on the bottom surface portion, and a small protrusion 72 that is guided and locked by the L-shaped notch 62 of the metal frame 6 is formed on the side surface portion.
[0024]
In such a configuration, when assembling, the upper frame 51 and the bottom frame with the light guide plate 3 sandwiched therebetween are fixed by the locking means, and the frame body 5 is completed. Next, the liquid crystal cell 1 is overlaid on the front surface side of the frame body 5, and the surrounding flexible substrate 14 with a driving element and the printed circuit board 13 are bent at a substantially right angle to the rear side of the liquid crystal cell 1, and then the section L The metal frame 6 is put over the formed angle 8. Then, the metal frame 6 is fixed to the frame body 5 by fixing means on the side surface of the metal frame 6 (see FIG. 1).
[0025]
Next, the light source unit 4 is positioned and arranged in the space 52 of the frame 5, and the unit fixing angle 7 is applied from below. Here, since most of the lead wires of the light source 41 are printed on the printed circuit board 44 and the printed circuit board 44 is integrated, the light source unit 4 does not interfere with the assembly. The power supply to the light source unit 4 can be performed through an electrical connection means such as a lead wire with a detachable connector as required. Then, the unit fixing angle 7 is inserted into the locking hole 433 of the support member 43 with the locking claw 71, and then the small protrusion 72 is attached to the metal frame 6 so that the side surface portion is applied to the inner side surface of the metal frame 6. The light source unit 4 is fixed by moving along the notch 62, that is, moving upward and then laterally (in the order of (a)-(b)-(c) in FIG. 7) (see FIG. 3). ).
[0026]
When the light source unit 4 is fixed, the lower end of the reflecting plate 42 comes into contact with the heat radiating plate 33 on the back surface of the light guide plate 3, so that the heat generated from the light source 41 passes through the reflecting plate 42 and the heat radiating plate 33 with good thermal conductivity. The liquid crystal cell 1 that is susceptible to heat influence can be protected from non-uniform heating by the light source 41. Moreover, since the upper end of the reflecting plate 42 contacts the reflecting sheet 53 on the back side of the upper frame 51, the reflecting sheet 53 can reliably prevent light leakage.
[0027]
Next, when the light source 41 is replaced, the fixing angle 7 is moved laterally and then downward from the illumination device 2, that is, the back side of the liquid crystal display device ((c)-(b)-in FIG. 7). Thus, the small projection 72 is removed from the L-shaped notch 62 of the metal frame 6 and the locking claw 71 is removed from the locking hole 433 to remove the unit fixing angle 7 (see FIG. 2). Next, the light source unit 4 is moved downward and taken out from the empty space 52 (see FIG. 1), and the electrical connection means is disconnected as necessary. Then, the light source 41 is removed from the light source terminal receiving portion 431 of the support member 43 and replaced. Here, a ring-shaped spacer 45 is attached to the new light source 41. When the light source 41 is integrated with the light source unit 4 and cannot be removed, the entire light source unit 4 may be replaced.
[0028]
In such a replacement operation of the light source 41, the liquid crystal cell 1 and the light guide plate 3 are housed and fixed by the metal frame 6 and the frame body 5, so that it is not necessary to align them again. No dust is mixed between the light guide plate 3 and the light guide plate 3. In the display device, the display surface is carefully observed, so that shadows appear on the display surface or foreign matter itself is observed, so that the display quality is significantly reduced. It is extremely useful that no dust is mixed in. Then, the light source unit 4 for which the replacement of the light source 41 has been completed is incorporated and fixed in the illumination device 2 as described above.
[0029]
Thus, since only the light source unit 4 can be attached and detached without disassembling the frame 5 constituting the illumination device 2 or the metal frame 6 constituting the liquid crystal display device, the workability of replacing the light source 41 can be greatly enhanced. .
[0030]
The lighting device 2 described above can be attached not only to the liquid crystal display device but also to other display devices.
[0031]
【The invention's effect】
According to the present invention, a light source unit is constituted by the light source, the reflection plate arranged so as to surround the light source, and the support member on which the light source and the reflection plate are fixedly arranged, and the light source unit can be attached to and detached from the frame body. As a result, the replacement work of the light source becomes extremely easy.
[0032]
In addition, the frame body has a space for arranging the light source unit from the back side of the frame body to the side of the light guide plate, and a fixing means for fixing the light source unit positioned and arranged in this space. It can be attached and detached from the back side of the frame body, and the light source replacement workability can be kept good even when the lighting device is thinned or various parts are arranged on the side surface and replacement from the side surface direction is difficult. it can. Furthermore, since the display surface side is not released, it is possible to prevent dust from entering between the display and the light guide plate.
[0033]
Moreover, since the light source unit has the printed circuit board on which the lead wire of the light source is wired and fixed to the support member, the lead wire is not loosened, and the light source unit can be easily replaced. Furthermore, since there is no positional deviation between the light source and its lead wire, it is possible to prevent the light source from becoming unstable due to impedance mismatch.
[0034]
And, since the reflector of the light source unit is a member with good thermal conductivity and it is configured to contact the heat radiating plate on the back of the light guide plate, the heat generated from the light source can be made uniform and radiated from the back side, Uneven heat effects on the front side display can be suppressed.
[0035]
[Brief description of the drawings]
FIG. 1 is an exploded cross-sectional view of a main part of a liquid crystal display device using an illumination device according to an embodiment of the present invention.
FIG. 2 is an exploded cross-sectional view of a main part of the same embodiment.
FIG. 3 is a cross-sectional view of a main part of the same embodiment.
FIG. 4 is a cross-sectional view of the light source unit of the embodiment.
FIG. 5 is a front view of a main part of the light source unit.
FIG. 6 is a main part rear view of the light source unit.
FIGS. 7A to 7C are explanatory views showing the attachment / detachment state of the unit fixing angle according to the embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Liquid crystal cell 2 Illuminating device 3 Light guide plate 33 Heat sink 4 Light source unit 41 Light source 42 Reflector 43 Support member 44 Printed circuit board 45 Ring-shaped space | interval 5 Frame 51 Upper frame 52 Space 6 Metal frame 7 Unit fixing angle

Claims (2)

A liquid crystal cell; a light guide plate disposed along a back surface of the liquid crystal cell; a light source unit that irradiates light to a side surface of the light guide plate; a frame body that positions and accommodates the light guide plate and the light source unit; A metal frame covering the liquid crystal cell, the light guide plate, the light source unit and the frame body from the surface side of the liquid crystal cell, and a fixing angle for fixing the light source unit,
The light source unit includes a light source, a reflecting plate disposed so as to surround the light source, a printed circuit board on which a lead wire of the light source is printed and wired, a support member in which the light source, the reflecting plate, and the printed circuit board are fixedly disposed. Consisting of
The frame has a space opened downward for detachably disposing the light source unit from the back side of the frame to the side of the light guide plate,
The fixing angle fixes the light source unit positioned and arranged in the space from the back side of the frame. The said light guide plate has a heat sink on the back surface, the said reflecting plate is a thing with good heat conductivity, It was set as the structure which this reflector plate contacts the back surface of the said heat sink. LCD display.

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