JP4572593B2 - Liquid crystal display - Google Patents

Description

  The present invention relates to a liquid crystal display device used for various display devices for in-vehicle use, and particularly in a small liquid crystal display device using a fluorescent tube (CFL) as a backlight light source, damage and disconnection of a lead wire drawn from the CFL. This is related to the protective structure of the CFL lead wire without the above.

  Display devices such as various on-vehicle meters and navigation devices are required to be power-saving, small, light, and thin, and liquid crystal display devices are often used as the display devices.

  In such a liquid crystal display device, a transmissive liquid crystal display device is used in which light from a backlight disposed on the back surface of the liquid crystal panel is irradiated on the back surface of the liquid crystal panel to view an image formed on the liquid crystal panel. As the backlight, a fluorescent tube (CFL) such as a hot cathode fluorescent tube (HCFL) or a cold cathode fluorescent tube (CCFL) is used. The backlight arrangement method includes a direct light method and a side light method. The direct light system is often used in liquid crystal display devices that require high brightness, such as large liquid crystal modules and medium-sized televisions. On the other hand, side-light type display devices are generally used for small-sized measuring devices, navigation devices, and various on-vehicle display devices that do not require so high luminance.

  Most of the sidelight type backlights use a light guide plate that changes a linear light source arranged on the side surface of the illumination device to a planar light source. A reflection plate is disposed on the back surface of the light guide plate, and an optical sheet called a prism sheet is disposed on the front surface. Conventionally, a linear cold cathode fluorescent tube (CCFL) has been often used as the light source, and the light source is disposed at the edge of the light guide plate, so it is also referred to as an edge light type backlight.

  A conventional liquid crystal display device using this type of sidelight type backlight will be described with reference to FIG. FIG. 5 is an exploded perspective view showing a state before the liquid crystal panel of the liquid crystal display device disclosed in Patent Document 1 is attached.

  That is, the liquid crystal display device 100 shown in FIG. 5 includes a liquid crystal panel 111, an illumination device 112 that illuminates the liquid crystal panel 111 from the back, and a metal support frame 113 that supports the liquid crystal panel 111 as main components. Yes. In a general liquid crystal display device, a liquid crystal panel 111 is sandwiched and supported between a front support frame 113a and a back support frame 113b similar to the support frame 113a. The liquid crystal panel 111 is configured such that liquid crystal is sealed between a pair of glass plates, and the display area faces forward from a window formed in the front support frame 113a. The illuminating device 112 is attached so as to face the light guide plate 121 dropped into the recess formed in the support frame 113b serving as a casing of the liquid crystal display device and the side end surface that is the light incident surface of the light guide plate 121 close to or in close contact with each other. In addition, one or a plurality of backlight light sources 122 are provided.

  In the liquid crystal display device of FIG. 5, holding members 131a to 131d having electrical insulation properties shown in FIG. 6 are provided at the four corners of the metal support frame 113b, and the holding members 131a to 131d are engaged with the support frame 113b. Engaging means, liquid crystal panel positioning means 133 for positioning the liquid crystal panel 111 on the holding members 131a to 131d, light guide plate positioning means 134 for positioning the light guide plate 121 on the holding members 131a to 131d, and holding the light source 122. The light source positioning means 135 for positioning the members 131a to 131d and the lead wire fixing means 136 for fixing the input / output lead wire 122a of the light source 122 within the support frame 113 are provided, and the input / output lead wire 122a of the light source 122 is further bundled. Lead wire drawing guide means 137 is provided.

  As shown in FIG. 7, the lead wire pulling guide means 137 includes a plurality of ribs 165 formed on the holding member 131c, and a bushing 166 that presses and fixes the input / output lead wires 122a back and forth in a bundled state. The bushing 166 has a female portion 167 and a male portion 168 that can be opened and closed via a hinge portion 169, and holds the input / output lead wire 122a in a closed state. The bushing 166 is made of an electrically insulating synthetic resin such as nylon so as not to damage the lead wire 122a. An engagement groove 172 that engages with the side wall 171 of the support frame 113 is formed on the outer peripheral surface of the female portion 167. Reference numeral 144 denotes a frame body of the support frame 113.

  However, in this type of conventional liquid crystal display device, the backlight light source 122 is fixed to the support frame 113b on the back surface of the illumination device, and the lead wire 122a of the CFL light source is connected to the metal support frame 113a on the front surface. Since it is led out from the notch portion of the support frame 113b on the back surface, it contacts the sharp edges of the notch portions of the support frames 113a and 113b at the time of mounting on the vehicle or during operation, and the lead wire coating is damaged and becomes a malfunction. Or disconnection due to vibration. Especially when mounting on a car, etc., the lead wire is routed to the back side or side of the liquid crystal display device in a limited space, making it easy to contact the notch, and the lead wire is placed in the limited space. Therefore, there is a high risk of disconnection because a force due to vibration is applied to the part while the state in contact with the notch is continued. The bushing 166 is for preventing this, and a product made of an electrically insulating synthetic resin is used. However, since the bushing 166 must be fixed to a metal support frame, the assembly is troublesome. Further, the bushing 16 impedes the degree of freedom in routing the lead wire, which again makes assembly difficult.

In the above conventional example, holding members 131a to 131d having electrical insulation are provided at the four corners of the metal support frame 113b. However, the holding members 131a to 131d are separated from each other. The assembly process of positioning and fixing by the engaging means and assembling the liquid crystal panel 111, the light guide plate 121, etc. was complicated.
Japanese Patent No. 2724642 (paragraphs [0021] to [0036], FIG. 1, FIG. 4, FIG. 10)

  The inventor of the present application has made various studies in order to solve the above-described problems. As a result, an optical sheet and a diffusion plate which are disposed in parallel to the liquid crystal panel on the back surface of the liquid crystal panel of the liquid crystal display device, and the diffusion plate Focusing on a lighting device having a backlight light source such as CFL and a reflecting plate disposed on the peripheral end surface of the glass, and upper and lower cases made of synthetic resin for sandwiching the lighting device to draw out lead wires of the light source, and The present inventors have found that the problem can be solved by covering the periphery of the lead wire outlet of the metal front frame and the back shield cover with lead wire protecting means provided on the upper and lower cases, and have completed the present invention. Is.

  That is, the present invention relates to a means for protecting lead wires of an illumination light source in a liquid crystal display device, and in particular, covers the lead wires drawn from the light source of the illumination device of the liquid crystal display device, and the edges of the upper and lower cases of the illumination device Another object is to prevent damage from metal edges such as the front frame and shield cover of the liquid crystal display device.

  Further, the present invention is configured so that the lighting device can be assembled with an upper case and a lower case made of synthetic resin, preventing damage to the lead wires of the light source, and facilitating the assembly of a small liquid crystal display device member. It is intended to provide.

  In order to solve the above problems, the invention of a liquid crystal display device according to claim 1 of the present application includes a liquid crystal panel, a lighting device having a light source disposed on the back surface of the liquid crystal panel, the liquid crystal panel, and the lighting device. In a liquid crystal display device comprising a metal front frame and a metal back shield cover to be housed, the lighting device is sandwiched between upper and lower cases made of resin, and the metal front frame and back shield The lead wire outlet provided in the cover is covered with lead wire protection means provided in at least one of the upper and lower cases.

  The invention according to claim 2 of the present application is the liquid crystal display device according to claim 1, wherein the lead wire protection means is a ridge provided at a lead wire outlet formed in the case, It is characterized by being formed so as to reach the position of the lead wire outlet provided in the front frame and the shield cover on the back.

  The invention according to claim 3 of the present application is the liquid crystal display device according to claim 1 or 2, wherein the lead wire positioning means is provided at one end of the back surface of the lower case where the illumination device is disposed. The lead wire is provided to the back side of the lower case, and is taken out from the lead wire outlet provided in the metal front frame and back shield cover via the positioning means. And

  The invention according to claim 4 of the present application is the liquid crystal display device according to claim 1 or 2, wherein the lead wire protection means is formed in an upper case, and the upper case is a conductive synthetic resin. It is characterized by that.

  The invention according to claim 5 of the present application is the liquid crystal display device according to claim 1 or 2, characterized in that the lead wire protection means is an elastic synthetic resin.

  According to the first aspect of the invention, the covering of the lead wire of the light source of the illuminating device drawn out from the liquid crystal display device is applied to the edges of the upper and lower cases of the illuminating device, and the metal edges such as the front frame and shield cover of the liquid crystal display device. Can be prevented from being damaged by. In addition, since the lighting device is assembled by sandwiching it between the upper case and the lower case made of synthetic resin, it is possible to prevent damage to the lead wires of the light source and to easily assemble the members of the liquid crystal display device. become able to. Furthermore, there is no need to provide an electrically insulating holding member on the metal front frame or the back shield cover, and no special processing necessary for attaching the holding member is required. Will be able to provide.

  According to the second aspect of the present invention, the lead wire protection means makes the surface of the case flush with the surface of the metal front frame or shield cover. Wire covering can be prevented from being damaged by metal edges such as the edges of the upper and lower cases of the lighting device, the front frame of the liquid crystal display device, and the shield cover.

  According to the invention of claim 3, in addition to the above-described effect, the lead wire of the light source is led to the back side of the lower case and pulled out through the positioning means. The holding and fitting of the upper and lower cases and the drawing of the lead wire are facilitated. Furthermore, since the lead wire is not drawn directly from the lighting device but on the back side of the lower case, entry of dust and the like can be prevented and adverse effects on the display can be suppressed. Since the lead wire is not arranged in the lighting device, the frame can be narrowed.

  According to the invention of claim 4, since the upper case is made of a synthetic resin having conductivity, it is difficult for noise to be generated due to static electricity or for parts to be destroyed.

  Furthermore, according to the invention of claim 5, since the lead wire protection means is a synthetic resin having elasticity, even if the lead wire is bent when the liquid crystal display device is assembled or attached, the stress is Since it is absorbed by the synthetic resin having elasticity, the lead wire protection effect is further improved.

  Hereinafter, embodiments of the liquid crystal display device according to the present invention will be described in detail with reference to the accompanying drawings. However, the embodiment shown below shows an example of a liquid crystal display device for embodying the technical idea of the present invention, and is not intended to specify the present invention as this liquid crystal display device. Other embodiments within the scope of the claims are equally applicable.

  FIG. 1 is an exploded perspective view showing the structure of a liquid crystal display device according to the present invention in order, with the front and back sides of the liquid crystal display device facing down and the constituent members in order. FIG. 2 is an external perspective view of a liquid crystal display device constructed by assembling the components shown in FIG. FIG. 3 is an enlarged perspective view of the vicinity of the lead wire outlet of the light source of the liquid crystal display device of FIG. FIG. 4 is a partially enlarged sectional view taken along line A-A ′ of FIG. 3.

  In FIG. 1, a liquid crystal display device 10 includes a front frame 21 that is a frontmost frame of a liquid crystal display device that is attached to the front surface of the liquid crystal panel, a liquid crystal panel 30, and a lighting device 40 that is disposed on the back surface of the liquid crystal panel. It comprises a circuit board 50 on which a plurality of electronic components such as an IC for controlling a liquid crystal panel driving IC are mounted, and a shield cover 22 fitted to the front frame 21.

  The liquid crystal panel 30 is connected to a circuit board 50 for driving the liquid crystal panel through a flexible printed wiring board 31 from a terminal portion provided on one side thereof.

The lighting device 40 in this embodiment is
(1) an approximately box-shaped lower case 42 formed by a synthetic resin mold;
(2) a reflecting plate 46 provided on the inner surface of the lower case 42 and having two opposing sides rising from the bottom along the side wall so as to form lamp houses 461 and 462 and bent into an L-shaped cross section;
(3) a light source 45 which is a linear cold cathode fluorescent lamp CCFL formed in a U-shape, which is disposed on three sides of the lower case 42 on the reflecting plate 46;
(4) A diffusion plate 44 made of an acrylic resin light guide plate and a diffusion sheet applied to the light guide plate, the side end surfaces of which are closely or closely surrounded by the light source 45;
(5) an optical sheet 43 including two prism sheets 43a and 43b disposed on the front surface of the diffusion plate 44;
(6) an upper case 41 fitted into the lower case 42 containing these members;
Consists of.

  A lead wire 47 is drawn from both ends of the light source 45, and a connector 48 is attached to one end thereof. The upper case 41 is formed of a conductive synthetic resin mold, and the back surface of the liquid crystal panel 30 is illuminated by light emitted from the opening 411 on the front surface of the frame-like case. The upper case 41 is specifically made of resin mixed with a conductive filler, and is generated from a light source by contacting or connecting to a metal front frame 21 or a metal shield cover 22 and taking a ground. The influence of the noise on the liquid crystal panel 30 can be effectively prevented.

  The lower case 42 is provided with positioning means 421 for the lead wire 47 at one end of the back side 42b of the side 42a where the light source 45 is disposed close to or in close contact with the end face of the diffusion plate 44. That is, the lead wire 47 of the light source 45 passes through two vertically extending grooves 422 provided on the side surface of the lower case from the side 42 a where the light source 45 of the lower case 42 is disposed close to or in close proximity to the end surface of the diffusion plate 44. It is guided to the back side 42 b of the lower case 42 and pulled out from the lead wire outlet 423 through the positioning means 421. This positioning means 421 has a structure in which two protrusions are arranged in parallel, and a lead wire 47 is sandwiched between them.

  With such a configuration, the lighting device 40 is assembled by being sandwiched between the upper case 41 and the lower case 42 made of synthetic resin, so that the lead wire 47 of the light source 45 is prevented from being damaged and the liquid crystal display device is assembled. It can be done easily. In addition, since the lead wire 47 is guided to the back side of the lower case 42 and pulled out through the positioning means 421, it is easy to hold the light source, fit the upper and lower cases, and pull out the lead wire.

  Furthermore, since the lead wire is not drawn directly from the lighting device 40 but on the back side of the lower case 42, entry of dust or the like into the lighting device 40 can be prevented and adverse effects on the display can be suppressed. That is, since there is a distance between the groove 422 in the vicinity of both ends of the light source 45 and the lead wire outlet 423, dust entering from the lead wire outlet 423 is difficult to reach both ends of the light source 45. Further, since the lead wire is not disposed in the lighting device 40, the frame can be narrowed.

  The upper case 41 is fitted to the outside of the lower case 42 like a lid that wraps the lower case 42, and a hook 424 provided on the outer peripheral side surface of the lower case 42 and an annular engaging means 412 provided around the frame of the upper case 42. Both cases are fixed by meshing. In the drawing, eight hooks 424 and eight engaging means 412 are provided. The lead wire outlet 413 of the upper case 41 and the lead wire outlet 423 of the lower case 42 overlap each other, and the lead wire outlet 413 of the upper case 41 is positioned in front of the lead wire outlet 423 of the lower case 42, and leads Lead wire protection means 414 covers the periphery of the wire outlet 423.

  In the embodiment, the lead wire outlet 423, the lower case hook 424, and the upper case engaging means 412 are provided at corresponding positions. In this way, the lead wire protection means 414 and the engagement means 412 can be integrally formed, so that the lead wire protection means 414 that is very effective in terms of strength and space can be provided.

  The lead wire protection means 414 is formed integrally with a conductive synthetic resin in the same manner as the upper case 41 and has a smooth outlet, or is covered with an elastic material such as conductive silicone rubber. ing. When at least the upper case 41 is formed of a conductive material, it reduces the generation of static electricity and helps to prevent noise and electrostatic breakdown of parts. Further, when the lead wire protection means is formed of an elastic material, the lead wire is less likely to be damaged, and thus the lead wire is more easily protected.

  Thus, by providing the upper case 41 and the lower case 42, it is not necessary to provide a lead wire holding member having electrical insulation on the metal support frame as in the conventional example, and the lead wire holding member is attached. Since such special processing is not required, manufacture and assembly are facilitated.

  The circuit board 50 incorporates various electronic component circuits such as a liquid crystal panel driving IC 501 and an external connection connector 502, and is arranged to be engaged with a lower case protrusion 425 provided on the back side 42b of the lower case 42. Is done. A ground pad for grounding the shield cover 22 and the ground is formed on the circuit board 50, and comes into contact with a connection piece provided on the back surface of the shield cover 22. A flexible printed wiring board 31 attached to a terminal portion provided on one side of the liquid crystal panel 30 is connected to the connector 503.

  The shield cover 22 is made of metal, covers the circuit board 50, and is fixed to the protrusions of the lower case 42 with screws 223. Similarly, the metal front frame 21 is put on the shield cover 22 on the back of the liquid crystal display device from the front, and the front frame 21 and the shield cover 22 are engaged with the holes 211 provided on the front frame and the claws 221 provided on the shield cover. Combined by the engaging means, the above-mentioned member is sandwiched from the front and rear.

  As described above, the liquid crystal display device of the present invention can be assembled by the engagement of the upper case 41 and the lower case 42, and the front frame 21 and the shield cover 22, so that the assembly is very easy.

  Next, the configuration in the vicinity of the lead wire outlet of the light source 45 of the liquid crystal display device according to the present invention will be described in detail with reference to the enlarged perspective view of FIG. 3 and the partial cross-sectional view of FIG. 4A-A ′. FIG. 3 is a view of the vicinity of the lead wire outlet of the light source 45 of the liquid crystal display device of FIG. 2 as viewed obliquely from below.

  In the liquid crystal display device 10, the front frame 21 is fitted into the shield cover 22 and engaged by the engaging means, and the lead wire 47 is drawn out from the lead wire outlet. The metal edges of the front frame 21 and the shield cover 22 are in a position retracted from the takeout port so as not to touch the lead wire 47 of the light source 45. From the lead wire outlet, the upper case outlet 413 and the lower case outlet 423 that surround the three sides overlap each other, but the lead wire protection means 414 formed on the upper case covers the front side and the inner side of the outlet. Covered with a smooth surface. The lead wire protection means 414 extends to the edge of the metal of the front frame 21 and the shield cover 22, and the front surface thereof is substantially flush with the surface of the front frame 21 to eliminate the step. Further, the portion of the upper case outlet 413 is shaped like a gentle peak. Note that the flexible connection line 503 is connected to the external connection connector 502 of the circuit board 50 and is drawn from the opening 222 of the shield cover 22.

  Here, a specific configuration of the lead wire outlet will be described with reference to a partial cross-sectional view shown in FIG. As apparent from the description of FIG. 3, the metal edges of the front frame 21 and the shield cover 22 are in a position retracted from the outlet. At the take-out port, the metal edge on the bottom surface of the shield cover 22 has an end surface 224 bent so that a sharp cut surface is not exposed. In such a configuration, it is impossible to provide the front frame 21 and the shield cover 22 on the portion where the front frame 21 and the shield cover 22 overlap, that is, on the side surface portion of the front frame 21 and the shield cover 22. This configuration is possible, and even if the lead wire 47 of the light source 45 is moved to the back side of the shield cover 22, the damage can be avoided. In particular, since the lead wire 47 is often routed and connected to the back side, bending the end surface 224 as described above is effective in protecting the lead wire 47. The upper case outlet 413 and the lower case outlet 423 overlap so that the upper case protection means 414 protrudes to the surface, and the lead wires 47 at the side portions of the front frame 21 and the shield cover 22. Damage and disconnection can be avoided.

  In the above embodiment, the lead wire protection means 414 is provided in the upper case, but the lead wire protection means 414 may be provided in the lower case.

  The light source 45 in the above description may be not only the cold cathode fluorescent tube CCFL but also the hot cathode fluorescent tube HCFL.

  Note that the liquid crystal panel used in the present invention may be a simple matrix type, an active matrix type, or another type.

  Also, the size of the liquid crystal panel is suitable for a small one, but is not necessarily limited. The present invention can be applied not only to a small in-vehicle information terminal and various meters but also to a relatively large liquid crystal display device. It is.

1 is an exploded perspective view illustrating the structure of a liquid crystal display device according to the present invention. FIG. 2 is an external perspective view of a liquid crystal display device configured by assembling the components shown in FIG. 1. FIG. 3 is an enlarged perspective view in the vicinity of a lead wire outlet of a light source of the liquid crystal display device of FIG. 2. FIG. 4 is a partially enlarged cross-sectional view taken along line A-A ′ of FIG. 3. It is a disassembled perspective view of the liquid crystal panel of the conventional liquid crystal display device. It is a perspective view of the holding member in the conventional liquid crystal display device. It is a perspective view of the lead wire drawer | drawing-out guide means of the light source in the conventional liquid crystal display device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Liquid crystal display device 21 Front frame 22 Shield cover 31 Flexible printed circuit board 40 Illumination device 41 Upper case 42 Lower case 45 Light source (CFL)
47 Lead wire 414 Lead wire protection means

Claims (3)

A liquid crystal display comprising a liquid crystal panel, a lighting device having a light source disposed on the back of the liquid crystal panel, a metal front frame and a metal back shield cover for housing the liquid crystal panel and the lighting device In the device
The lighting device is held between the upper and lower cases made of resin, the periphery of the metal front frame and the rear shield lead wire outlet port provided on the cover, covered with lead protection means provided Ueke over scan and,
The lead wire protection means is a ridge provided in a lead wire outlet formed in the upper case, and is formed to be substantially flush with the lead wire outlet provided in the front frame and the rear shield cover. ,
The lead wire positioning means is provided at one end of the back surface of the lower case where the lighting device is disposed,
The lead wire is led to the back side of the lower case, and is taken out from the lead wire outlet provided in the front frame and the back shield cover through the positioning means,
The liquid crystal display device according to claim 1, wherein an end surface of a bottom surface portion of the lead wire outlet provided in the back shield cover is bent . The liquid crystal display device according to claim 1, characterized in that the pre-SL upper case is a synthetic resin having conductivity.   3. The liquid crystal display device according to claim 1, wherein the lead wire protection means is a synthetic resin having elasticity.

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