Patent Application
20080019152
1. Field of the Invention
The present invention relates to a light-source holder, an illumination device for a display device, and a display device.
2. Description of the Related Art
In a non-luminescent display device such as a liquid crystal display device, a backlight unit is provided at the back surface of a panel so as to illuminate it. See, for example, Japanese Patent Laid-Open No. 2001-210126. This backlight unit is configured such that a plurality of light sources such as cold cathode tubes are arranged in parallel and contained inside a case which is formed into a shallow pan shape.
These light sources are fixed to the bottom plate of the case with a light-source holder, such as a lamp clip formed of resin, etc. This lamp clip is configured such that in its body part there is provided on a surface opposed to the case bottom plate an engaging part for engaging with the case, and on the opposite surface a clipping part for holding the light source. The engaging part includes a base part protruding from the body part and a locking head of a large diameter provided at the protruding end of the base part. Thus, the base part is inserted into a mounting hole provided in the case bottom plate and the locking head is locked onto the peripheral margin of the mounting hole in the back surface of the bottom plate so that the lamp clip is locked onto the bottom plate.
However, since there is a certain dimensional tolerance in the production stage, the distance between the body part and the locking head of the lamp clip may become larger than the thickness of the case bottom plate. In such a case, backlash between the attached lamp clip and the bottom plate of the case is experienced, and thus, there is risk that a chattering sound or the like may be generated due to the vibration of the device or the like.
In order to overcome the problems described above, preferred embodiments of the present invention provide a light-source holder that prevents backlash between the light-source holder and the holding wall for the light-source holder.
The light-source holder according to a preferred embodiment of the present invention, which is intended to hold a light source on a holding wall, includes a body part adapted to be put into contact with the holding wall, a locking part protruding from the body part toward the holding wall and being arranged to be locked onto the holding wall, and a spring part provided in the body part on a surface opposed to the holding wall and adapted to bias the body part in a direction so as to be spaced apart from the holding wall. In the light-source holder according to a preferred embodiment of the present invention, the benefits of this preferred embodiment of the present invention can be achieved as long as a spring part is provided at least one or more places in the body part.
In one preferred embodiment of the light-source holder of the present invention, a spring part may be provided at least two places on either side of the locking part. Such a configuration can restrict the inclination of the body part with respect to the holding wall thereby anchoring the body part to the holding wall with good balance. In another preferred embodiment of the light-source holder of the present invention, at least one pair of the springs may be provided at positions opposed to each other. Such a configuration can restrict the inclination of the body part with respect to the holding wall thereby anchoring the body part with good balance.
In a further preferred embodiment of the light-source holder of the present invention, the spring part may be a plate spring which is integrally formed with the body part and is projected toward the holding wall in a cantilever arrangement. According to such a configuration, since the spring part can be integrally formed with the body part, it is possible to decrease production steps thereby reducing cost compared with the case in which a spring part which is formed separately from the body part is attached to the body part. In this case, at least one pair of plate spring parts may be projected in opposite directions from each other. Such a configuration can restrict the inclination of the body part with respect to the holding wall thereby anchoring it with good balance.
In a further preferred embodiment of the light-source holder of the present invention, the spring part may be provided at at least one place between a plurality of locking parts. Such a configuration can also restrict the inclination of the body part with respect to the holding wall thereby anchoring the body part with good balance.
In a further preferred embodiment of the light-source holder of the present invention, the configuration may be such that two or more light sources can be held by one light-source holder. Such a configuration can reduce the number of parts and thereby simplify the production process.
The light-source holder according to a preferred embodiment of the present invention can be preferably applied to an illumination device for a display device. That is, the illumination device for a display device according to a preferred embodiment of the present invention includes a light-source holder having the above described configurations, a light source to be held by the light-source holder, and a case part having the above described holding wall and arranged to accommodate the above described light source and light-source holder. In one preferred embodiment of the illumination device for a display device according to the present invention, the light-source holder may be formed of polymeric material, for example. With polymeric material, it is possible to produce a light-source holder having a spring part at low cost and with ease by, for example, an injection molding thereby reducing the cost. Also in another preferred embodiment of the illumination device for a display device according to the present invention, the light-source holder may have a white color. Instead, the light-source holder may have a milky-white color. Further, the light-source holder may be transparent. According to such a configuration, it is possible to avoid the deficiencies such as a decline in luminance due to the blockage of light by the light-source holder since the light from the light source is reflected from or transmits through the light-source holder.
The above-described illumination device for a display device is preferably applied to a display device. That is, the display device according to a preferred embodiment of the present invention is configured such that an illumination device for a display device having the above described configurations, an optical member for diffusing the light from the illumination device for a display device, and a non-luminescent display panel are laminated in this order. In one preferred embodiment of the display device of the present invention, the display panel may be configured to electrically control the deflection property of electro-magnetic wave. In a further preferred embodiment, the display panel may be configured to control the intensity of electro-magnetic wave by a physical or mechanical shuttering scheme. In a further preferred embodiment, the display panel may be a liquid crystal display panel, and the display device may be a liquid crystal display device.
According to a preferred embodiment of the present invention, when attaching the light-source holder to the holding wall, the body part is biased in a direction so as to be spaced apart from the holding wall by the resilience of the spring part, and thereby locked in a state in which the locking part is pressed against the peripheral margin of the insertion hole in the back surface of the holding wall. In this way, it is possible to prevent the backlash between the light-source holder and the holding wall thereby preventing a chattering sound or the like from being generated.
Other features, elements, processes, steps, characteristics and advantages of the present invention will become more apparent from the following detailed description of preferred embodiments of the present invention with reference to the attached drawings.
Hereinafter, a first preferred embodiment of the present invention will be described in detail with reference to FIGS. 1 to 7.
The liquid crystal display panel 10, though not shown in detail, has a well known structure in which a pair of glass substrates having a substantially rectangular plate shape, on which switching elements (for example, TFTs), pixel electrodes, and others for forming pixels are arranged in a matrix form, are bonded together with a predetermined gap and liquid crystal material is sealed in between both the glass substrates. The outer surfaces (the surface opposite to the liquid crystal layer) of both the glass substrates are laminated with a polarizing plate which have approximately the same size as each glass substrate.
The backlight unit 20, which is to be attached in the back surface side of the liquid crystal display panel 10 is of a direct type in which the light source is disposed in the back surface of the liquid crystal display panel 10, includes a backlight case 21 made of metal (corresponding to the case part of the present invention; hereinafter, abbreviated as “case 21”), and a plurality of cold cathode tubes 81 contained in the case 21 (corresponding to the light source of the present invention, see also
The case 21 includes a bottom plate part 22 having a substantially rectangular plate shape (corresponding to the holding wall of the present invention), which has approximately the same size as the liquid crystal display panel 10, and a side wall part 23 which is raised respectively from each of the four sides of the bottom plate part 22 toward the front face side, the case as a whole being formed approximately into an shallow pan shape with an opening in the front surface side. There are provided at an even pitch in either short side of this case 21 a large number of fit-in grooves 24, which are formed by cutting off the bottom plate part 22 from the raised end of the side wall part 23A of a short side to a position at a certain short distance inward toward the center from the short side, and into which a rubber holder 51 described later can be fitted (see
In the case 21, a reflection sheet 31 for reflecting the light emitted from a cold cathode tube 81 (described later) is laid. The reflection sheet 31 is preferably a white sheet formed of synthetic resin, and is formed by alternately combining two divided sheets 32 having the same shape. Each divided sheet 32 is preferably configured as follows: a bottom-plate side sheet piece 32A, which matches with the bottom plate part 22 of the case 21, is divided into two pieces at the central position in the lengthwise direction thereof; and a side part of each divided piece along the long side of the case 21 is respectively connected with a side-wall side sheet 32B, which matches the side wall part 23 on the long side of the case 21. This reflection sheet 31 is provided with an attachment hole 33 at a position which matches with each insertion hole 25 of the case 21 described above.
There is provided on the reflection sheet 31 a cold cathode tube 81 which is a light source. The cold cathode tube 81 preferably includes a tube body elongated in the long-side direction of the case 21, and a plurality of the cold cathode tubes 81 are disposed in parallel along the short-side direction of the case 21. There is provided at the end of the cold cathode tube 81 an electrode part, although not shown in detail, from which an electric wire is led out. Further, each end of the cold cathode tube 81 is held by a rubber holder 51 which is disposed on each short-side part of the case 21, and is covered as a whole together with the rubber holder 51 by a lamp holder 41 (see
Further, the cold cathode tube 81 is held at a position which is closer to its center than to its end by a lamp clip 61 (corresponding to the light-source holder of the invention). The lamp clip 61, which is preferably formed as one piece from synthetic resin, is attached to the inner wall surface of the bottom plate part 22 of the case 21 thereby holding the cold cathode tubes 81 at positions closer to its center than to its ends. The lamp clips 61, each of which is capable of holding cold cathode tubes 81 in a set of two rows, are provided at two places for each set (2 rows) of cold cathode tubes 81, and the lamp clips 61 for supporting cold cathode tubes 81 in adjoining sets are disposed in a staggered configuration. Further, since the lamp clip 61 is to be disposed in the display area of the liquid crystal display panel 10, when it is adapted to have a color which absorbs the light for example from the cold cathode tube 81, there is risk of causing deficiencies such as a decline of luminance. To avoid this, the lamp clip 61 is adapted to have a white color so that it can reflect the light from the cathode tube 81 in the same way as the reflection sheet 31.
The lamp clip 61 preferably includes a body part 62 having an elongated, substantially rectangular plate shape along the short-side direction of the bottom plate part 22 (a direction normal to the length of the cold cathode tube 81). There are provided on the front surface side of the body part 62 (the other side of the surface opposed to the bottom plate part 22), two clipping parts 63 for holding the cold cathode tube 81, disposed in parallel along the lengthwise direction of the body part 62 (see
Further, there is provided in the back surface side (on the side of the surface opposed to the bottom plate part 22 of the case 21) of the body part 62 a pair of locking parts 65 for fixing the lamp clip 61 to the bottom plate part 22. Each locking part 65 is located exactly on the other side of each clipping part 63, respectively. The locking part 65 includes a base part 65A which is vertically disposed on the back surface of the body part 62, and a pair of elastic locking pieces 65B which is projected diagonally forward from the tip part of the base part 65A, i.e. toward the body part 62 while becoming spaced apart from the base part 65A. Both the elastic locking pieces 65B are configured in the form of a cantilever connected to both sides of the tip part of the base part 65A, and adapted to be elastically deformable in the direction moving closer to or away from the base part 65A by being pivoted at the connection portion. The projection end of the elastic locking piece 65B is formed with steps, in which the step outwardly located in the expanding direction is reduced in its height (recessed in the direction away from the body part 62). The surface of the outwardly located step with a reduced height is adapted to serve as a locking surface 65C to be locked onto the peripheral margin of the insertion hole 25 in the back surface of the case 21. The space between the back surface of the body part 62 and the locking surface 65C is adapted to be approximately equal to or slightly larger than the thickness of the bottom plate part 22.
Moreover, there are provided in the body part 62 a pair of plate spring parts 66 each of which is formed into a cantilever form. The two plate spring parts 66 are provided near opposite ends of the pair of long-side parts in the body part 62, that is, at opposite positions on either side of the two locking parts 65. Each plate spring part 66 is configured such that two parallel slits 67 along the short-side direction are provided near the end part of each long-side part in the body part 62, and a cut-in piece formed between the slits 67 is configured to be slanted in such a way to descend toward the back surface direction (toward the surface where the locking part 65 is formed) progressively toward the outside (edge side). The plate spring parts 66 are projected to a position which is located slightly closer to the back surface than the projection end of the elastic locking piece 65B is, and the tip part of the plate spring part is extended in parallel with the plate surface of the body part 62. Thus, the tip part is configured as a contact part 66A to be put into contact with the bottom plate part 22 when the lamp clip 61 is attached to the case 21.
There is attached at the opening part of the case 21 in such a way to cover the opening part, an optical member 71 for diffusing the light from the cold cathode tube 81, which is a linear light source, and emitting it to the liquid crystal display panel 10 as uniform planar light. The optical member 71 preferably is configured such that a diffusion sheet 72, a lens sheet 73, an optical sheet 74, and a diffusion plate 75 are superposed from the front surface side in that order. Each sheet 72, 73, 74, 75 preferably has a substantially rectangular shape of almost the same size as the liquid crystal display panel 10, and is supported from the back surface side by a pin 64 of the lamp clip 61. Further, a frame 76 for the attachment of the optical member 71 is disposed respectively in the front surface side and back surface side thereof. Further, there is attached in the back surface of the case 21 an inverter unit 91 and an external circuit unit 92 for controlling the lighting of the cold cathode tube 81.
Next, the function and effects of preferred embodiments of the present invention configured as described above will be described.
In assembling the liquid crystal display 1, a reflection sheet 31 is laid on the bottom plate part 22 of the case 21. Then, over the reflection sheet 31, the lamp clip 61 is attached to the bottom plate part 22 (
When the lamp clip 61 has been attached, the cold cathode tubes 81, each of which is attached with a rubber holder 51 at its end, are placed in parallel in the case 21, and the tube body of the cold cathode tube 81 is supported by the clipping portion 63 of the lamp clip 61. Then, the lamp holder 41 is fit into the case 21 in such a way to cover the rubber holder 51. Then, the optical member 71, the frame 76, the inverter unit 91, and the external circuit unit 92 are assembled to the case 21 thus completing the assembly of the backlight unit 20. Finally, the backlight unit 20 is assembled from the back surface side of the liquid crystal display panel 10 and fixed by the bezel 13 thereby completing the liquid crystal display 1.
In using the liquid crystal display 1, the light emitted from the cold cathode tube 81, which is provided in the backlight unit 20, enters into the optical member 71 directly and by being reflected by the reflection sheet 31 on the back surface side, and is irradiated from the back surface side of the liquid crystal display panel 10 in a state of being diffused by the optical member 71 thereby causing a display on the liquid crystal display panel 10 to be visually recognized.
At this moment, since the lamp clip 61 is white colored so as to reflect the light from the cold cathode tube 81 as well as the reflection sheet 31, it is possible to avoid deficiencies such as a decline of luminance due to the blockage of light by the lamp clip 61.
As so far described, according to the present preferred embodiment, when the lamp clip 61 is attached to the bottom plate part 22, the body part 62 is biased in a direction to be spaced apart from the bottom plate part 22 by the resilience of the plate spring part 66, and is locked in a state that the locking surface 65C of the locking part 65 is being pressed against the peripheral margin of the insertion hole 25 in the back surface of the bottom plate part. This prevents the backlash between the lamp clip 61 and the bottom plate part 22, thereby making it possible to prevent a chattering sound and the like from being generated. Further, a pair of plate spring parts 66 are provided at opposed positions on either side of the locking part 65, and projected in opposite directions to each other. This makes it possible to support the body part 62 at both sides with good balance and anchor it to the bottom plate part 22 without inclination.
Further, since the plate spring part 66 is integrally formed with the body part 62, it is possible to reduce production steps compared with a case in which a spring body formed separately from the body part 62 is attached to the body part 62, thereby reducing cost. Further, since by forming the lamp clip 61 with resin, it is possible to produce a lamp clip 61 including a plate spring part 66 easily at low cost by, for example, an injection molding, cost reduction may be achieved. Further, by making the lamp clip 61 to have a white color so as to be able to reflect the light from the light source in the same way as the reflection sheet 31, it is possible to avoid deficiencies such as a decline of luminance.
Hereinafter, the second preferred embodiment of the present invention will be described in detail with reference to FIGS. 8 to 10. The lamp clip 101 of the present preferred embodiment includes a body part 102 having a substantially rectangular plate form as in the case of the first preferred embodiment, and the body part 102 is provided in its back and front surfaces with a clipping part 103, a pin 104, and a locking part 105 having a similar shape to those of the first preferred embodiment (
In the body part 102, both ends in the long-side direction is inclined so as to progressively descend toward the back surface side (where the locking part 105 is provided) starting from a point slightly inside the edge of the short side, and this inclined part is provided as the plate spring part 106. The inclination of these plate spring parts 106 is adjusted such that its tip part (edge of short side) is located slightly closer to the back side than the projection end of the elastic locking piece 105B. Since other configurations are the same as those of the first preferred embodiment, the like numbers are used to omit explanations.
In assembling the liquid crystal display of the present preferred embodiment, a reflection sheet 31 is laid on the bottom plate part 22 of the case 21 as in the case of the first preferred embodiment and over the reflection sheet 31, the lamp clip 101 is attached (
As described so far, the present preferred embodiment can also achieve similar effects to those of the first preferred embodiment.
The scope of the present invention will not be limited by the above described preferred embodiments. For example, the following other preferred embodiments are included in the scope of the present invention. Further, the scope of the present invention will cover equivalent variations.
(1) Although in each of the above-described preferred embodiments, the plate spring part 66, 106 preferably is integrally formed with the body part 62, 102 of the lamp clip 61, 101, the spring part may be separately formed and attached to the body part. Further, the configuration of the spring part will not be limited by the present preferred embodiments, and it may be a plate spring of a both-ends support type, a compressed coil spring, rubber, or the like.
(2) Although in the first preferred embodiment, the plate spring parts 66 preferably are projected respectively in the outward directions of the body part 62 in the lamp clip 61, a pair of plate spring parts may be projected respectively in the inward directions of the body part. Further, a pair of the plate spring parts may be projected in the same direction.
(3) Although in each of the above described preferred embodiments, there are preferably provided a pair of plate spring parts 66, 106 on either side of two locking parts 65, 105, one plate spring part 112 may be provided at a position between the locking parts 65 as shown by a lamp clip 111 in
(4) Although in each of the above described preferred embodiments, there are preferably provided a pair of plate spring parts 66, 106 on either side of two locking parts 65, 105, a pair of spring parts may be provided on either side of each of a plurality of locking parts.
(5) Although in each of the above described preferred embodiments, the lamp clips 61, 101 are preferably formed to be white in color, the lamp clip may be formed in a milky-white color or to be transparent allowing the transmission of light; in short, any configuration will suffice as long as no luminance decline occurs.
(6) Although, in the above described preferred embodiments, the present invention is preferably applied to the liquid crystal display 1, the present invention may be applied to any display device having a backlight device at the back face side of the display panel. Further, although the liquid crystal display panel 10 is configured to electrically control the deflection property of electro-magnetic wave (light), without being limited by this, the display panel may be configured to control the intensity of electro-magnetic wave by a physical or mechanical shuttering scheme.
(7) Although in the above described preferred embodiments, there are preferably provided two clipping parts 63 for one lamp clip 61 so as to be able to hold two cold cathode tubes 81, for example only one or not less than three clipping parts may be provided for one light-source holder so as to hold only one, or not less than three light sources.
While preferred embodiments of the present invention have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing the scope and spirit of the present invention. The scope of the present invention, therefore, is to be determined solely by the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2005-001644 | Jan 2005 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP05/22086 | 12/1/2005 | WO | 6/27/2007 |
