Patent Application
20050281037
The Nonprovisional application claims priority under 35 U.S.C. ยง 119(a) on Patent Application No. 2004-181370 filed in Japan on Jun. 18, 2004, and the entire contents of which are hereby incorporated in the present application by reference.
1. Field of the Invention
The present invention relates to an illuminating device for a display device, a lamp supporting member and a liquid crystal display device. More particularly, it relates to an illuminating device for a display device suitable for constituting a backlight of a transparent liquid crystal display device or semi-transparent one having a transparent region in a liquid crystal display element, a lamp supporting member which is used in the illuminating device for a display device, and a liquid crystal display device comprising the illuminating device for a display device.
2. Description of the Related Art
An illuminating device for a display device lights up a device having means for displaying by light and it is widely used in a backlight part and the like in a liquid crystal display device, for example. That is, since a liquid crystal panel does not emit light by itself in the liquid crystal display device, the illuminating device for a display device is generally provided as the backlight part for emitting light to the liquid crystal panel in the transparent liquid crystal display device or semi-transparent one. Such liquid crystal display device is indispensable to means for displaying information or screen images. High-quality products in which characteristics of the liquid crystal display such as low power consumption, light weight, and thin thickness are sufficiently implemented, have been recently focused in display panels of a consumer video monitor, an industrial equipment monitor, Personal Digital Assistant and the like, and are widely applied to various fields.
As a backlight used in the liquid crystal display device, there are two types such as an edge light (side backlight) and a direct backlight.
As a structural characteristic of the edge light, as shown in
Meanwhile, in the case of the direct back light, a plurality of the bar-like light sources 113 such as cold cathode fluorescent tubes are provided on the back surface of the display element 117 such as a liquid crystal panel as a structural characteristic as shown in
Such liquid crystal displays is advanced in the field of a small-sized display element and spreads in the market as a display of a laptop personal computer (PC) and a mobile phone and its technique has been developed. In these fields, a display size is mainly until 15-inch model and a slim shape is indispensable, so that the edge light is selected in view of merchantability.
At present, the liquid crystal display device has been dramatically enlarged because of completion of a process using a larger mother glass, so that it is used in a television (20-inch model to 50-inch model) for home use. In such television, brightness becomes more important basic performance than in the PC and the mobile phone. For example, while a luminance specification is about 250 candela (cd/m2) in the PC monitor in general, luminance specification has to be 500 candela (cd/m2) or more in the television. In this respect, the direct backlight is preferable in order to provide a large backlight having high luminance.
Regarding an illuminating device for a display device which may be used in a previous liquid crystal display device and the like, there are a lamp holder which is formed in a segmented gripping shape having an opening in one part and made of a transparent material having flexibility (disclosed in Japanese Kokai Publication 2001-210126 (pages 1-2 and 4), for example), a backlight assembly comprising a plurality of lamps comprising sub lamps, and a lamp holder for housing a connection part via which the sub lamps is connected to each other (disclosed in Japanese Kokai Publication 2004-55531 (pages 1-2, 7 and 13), for example), a backlight device in which a reflector for condensing light emitted from a light source in a light guide plate is formed of metal and supports the light source (disclosed in Japanese Kokai Patent Publication Hei-10-207406 (pages 1-2), for example), and a fluorescent lamp unit in which a fluorescent lamp is housed in a trough-shaped unit support, and a lamp support consisting of a translucent or light reflective synthetic resin is arranged between the fluorescent lamp and the unit support (disclosed in Japanese Kokai Patent Publication Hei-09-330613 (pages 1-2), for example). In addition, U.S. 2003/0227767 A1 is incorporated by Japanese Kokai Publication 2004-55531 by reference.
According to the previous lamp holder, since a pin for fixing the lamp holder is provided just under a fluorescent tube, light from the fluorescent tube leaks through the pin, which results in reduction of luminance at that part (refer to
The present invention was made in view of the above problems, and it is an object of the present invention to provide an illuminating device for a display device in which unevenness of luminance on an information display surface is prevented by securing a position accuracy of a light source lamp, light leakage from a lamp supporting member, lower luminance or unevenness of luminance is reduced, and excellent display quality may be provided, a lamp supporting member, and a liquid crystal display device comprising the illuminating device for a display device.
While the inventors of the present invention have studied various kinds of illuminating device for a display devices which may be preferably applied to a backlight and the like of the liquid crystal display device and may implement a large backlight having high luminance, they focused on a constitution in which a light source lamp is supported by a lamp supporting member and fixed to a back light angle (frame) to be mounted on the device, for example, a constitution which is formed in a segmented gripping shape having an opening in one part and made of a transparent material having flexibility as shown in
Thus, for example, when the fixing pin 12 of the lamp supporting member 11 is provided at a position other than a position just under the light source lamp 21, it is found that the light source lamp 21 is protected, unevenness of luminance on the information display surface is prevented by securing a position precision of the light source lamp 21, a level of the dark area caused by the light leaking due to the structure of the lamp supporting member 11 is decreased, the influence of the unevenness of luminance is sufficiently reduced and preferable display quality is provided, so that the above problems can be admirably solved. In addition, when the lamp supporting member 11 is formed of a reflective material, that is, when reflecting coefficient of the lamp supporting member 11 is increased by providing reflecting coating on the lamp supporting member 11 or forming the lamp supporting member 11 from high-reflective material, it is found that the operation and effect of the present invention can be sufficiently provided, thereby to attain the present invention.
That is, the present invention provides
In addition, the present invention provides
An illuminating device for a display device of the present invention comprises a light source lamp and a lamp supporting member, and the illuminating device is suitable for an illuminating device for a liquid crystal display device. According to the present invention, it is preferably used as a direct backlight. In addition, it may be applied to an edge light (side backlight). The lamp supporting member may be called a lamp holder. As the illuminating device, in the case of the direct backlight, there is a configuration in which the light source lamp is provided on a reflector through the lamp supporting member. In this constitution, one or more light source lamps are used, and it is preferable that the present invention is applied to the constitution in which a plurality of light source lamps are used.
In addition, in the case of the edge light, there is a configuration in which the light source lamp is provided on one or more side surfaces of a transparent light guide plate formed of resin through the lamp supporting member.
The illuminating device according to the present invention may include other component members as long as these necessary component members are provided.
When the illuminating device is used in the liquid crystal display device, the light source lamp is provided on a reflector in general, and various kinds of optical sheets such as a diffuser, a diffusion sheet, a condenser lens, a polarized light selective reflection/transmission sheet, a protection/diffusion sheet and an electromagnetic wave shielding sheet (conductive sheet, ITO sheet) and the like are laminated and provided thereon to constitute the illuminating device, which constitutes the liquid crystal display device together with a liquid crystal panel.
The illuminating device for a display device of the present invention has
In case that the illuminating device has the configuration (1), the fixing pin which engages with the backlight angle and the like, is provided at a position other than a position substantially just under the light source lamp in the lamp supporting member, so the amount of light leaking through the fixing pin may be reduced and generation of the dark area on the display surface may be prevented. In the case of the large backlight requiring high luminance in particularly, it is important to reduce such dark area.
The position of the fixing pin may be any place, as long as the position is the position other than the position just under the light source lamp and the operation and effect of the present invention such that light leakage is reduced and influence of the unevenness of luminance is reduced may be exhibited. The fixing pin is preferably provided apart from the position just under the light source lamp. For example, as shown in
According to the present invention, used may be the lamp supporting member (lamp supporting member for one tube) having a constitution in which one lamp supporting member has one member for gripping a light source lamp or the lamp supporting member (lamp supporting member for many tubes) having a constitution in which one lamp supporting member has a plurality of member for gripping a light source lamp.
The present invention may be the lamp supporting member for one tube having the configuration in which the lamp supporting member and the fixing pin are provided for each light source lamp independently, and be preferably the lamp supporting member for many tubes having the configuration in which the lamp supporting member have a plurality of members for gripping a light source lamp. When the two or more members for gripping a light source lamp are integrated, the number of parts may be reduced, and a distance between the members for gripping a light source lamp may be constant. Therefore the light source lamps may be easily supported at regular intervals with high precision, which enables low-cost manufacturing of the display device having high display quality. In this case, there is a configuration in which a plurality of straight-line portions of the light source lamp are supported by the integrated members for gripping the light source lamp, and a configuration in which a plurality of curved-line portions of the light source lamp are supported by the integrated members for gripping the light source lamp when the light source lamp has the curved-line portions.
As a preferable configuration of the present invention, there is
The lamp supporting member may be constituted by appropriately combining these configurations of (a) to (e).
According to the configuration (a), the fixing pin is provided substantially in the middle position between the light source lamps in the lamp supporting member having a plurality of structural parts for gripping the light source lamps.
Thus, since a distance between the light source lamp and the fixing pin may be almost constant, unevenness of luminance may be further reduced effectively and the light source lamp may be supported in a balanced manner. According to the configuration (a), the fixing pin is provided substantially in the middle position between the light source lamps, and it may be provided just in the middle position between the light source lamps or be provided in the position close to either one of the light source lamps as long as the distance between the light source lamp and the fixing pin is almost constant.
The number and the shape of the fixing pins provided in one lamp supporting member are not particularly limited in the present invention.
In the case of the lamp supporting members comprising two integrated structural parts for gripping the light source lamp and one fixing pin, as shown in
According to the configurations (b), (c), (d) and (e), since means for securing the position precision of the light source lamp is provided, unevenness of luminance caused by the displacement may be sufficiently prevented.
According to the configuration (b), the pin for controlling a position is provided in order to prevent displacement of the lamp supporting member. The number and the position of the pin for controlling a position of the lamp supporting member, and the shape are not particularly limited, and the pin for controlling a position of the lamp supporting member preferably has a structure in which light does not leak from the pin for controlling a position of the lamp supporting member. For example, as shown in
According to the configuration (c), since the fixing pin has the angular shape, displacement of the light source lamp may be further prevented as compared with the case where the fixing pin has the round shape. As the angular shape, there may be a rectangle, a square and the like.
In addition, according to the configuration (d), since the fixing pin has across section of being in an oblique direction to the planar shape of the lamp supporting member as viewed in plane, displacement is not likely to occur as compared with the case where the fixing pin has a cross section of being in the same direction to the planar shape of the lamp supporting member as viewed in plane. The fixing pin is provided so as to be parallel to the light source lamp in general, but in this case, the fixing pin is provided in the oblique direction with respect to a mounting direction of the light source lamp.
In
According to the configuration (e), as shown in
In
According to the configuration of the illuminating device of the present invention, the lamp supporting member may be provided in a display region or in a non-display region, and when it is provided in the display region, the lamp supporting member may be white or transparent. In addition, when the pin for supporting a diffuser is provided in the lamp supporting member, the pin for supporting a diffuser may be white or transparent.
In the case of the configuration (2), that is, when the lamp supporting member is formed of a reflective material, a reflective coefficient of the lamp supporting member may be increased by coating the lamp supporting member with the reflective material or forming the lamp supporting member with the reflective material. In this case, it is preferable that the lamp supporting member is white. Thus, exhibited is the operation and effect of the present invention in which the light leakage from the part of the fixing pin may be sufficiently prevented.
When the lamp supporting member is coated with a reflective material, the reflective coating material having reflectivity higher than that of the normally used material for the lamp supporting member is applied onto the lamp supporting member to form a coating film on the lamp supporting member. The kind of the reflective coating and the condition for coating the lamp supporting member are not particularly limited. In addition, when the lamp supporting member is formed of a reflective material, the material having reflectivity higher than that of the normally used material for the lamp supporting member is used to form the lamp supporting member. The kind of the high reflective material to form the lamp supporting member, the condition and the like for forming the lamp supporting member from the material are not particularly limited.
According to the illuminating device for a display device of the present invention, as the light source lamp, preferred are fluorescent tubes such as a cold cathode fluorescent tube, a hot cathode fluorescent tube and the like. As the light source lamp having the curved-line portion, a U-shaped-tube light source lamp, an S-shaped-tube light source lamp, a W-shaped-tube light source lamp and the like may be mentioned. When such light source lamp may be used, the number of parts is reduced and the total number of the electrodes of the light source lamp may be reduced, therefore whole power consumption of the illuminating device may be reduced. Among them, the U-shaped tube is preferable because reduction of manufacturing yield in the light source lamp is prevented and the effect such as reduction in power consumption may be provided. Furthermore, when the U-shaped tube or the like is used, since the electrodes of the light source lamp may be collected to one side thereof, drive circuits may be collected to the one side. Meanwhile, when the S-shaped tube or the like is used, since the electrodes of the light source lamp are provided on both sides thereof, optical characteristics of light from the light source lamp are uniformed.
The arrangement configuration of the light source lamp preferably has a configuration in which the straight-line portions of the light source lamp are parallel to each other and arranged at a regular interval in view of uniformity of light.
The lamp supporting member is preferably formed of an insulation resin. In addition, only one part of the lamp supporting member may be formed of an insulation resin as long as the light source lamp may be insulated from the base on which the light source lamp is positioned. As the insulation resin, an elastic material such as a rubber material is preferable. In this case, a problem caused by low impact resistance of the light source lamp may be sufficiently solved. In addition, the insulation resin preferably has flexibility.
Furthermore, it is preferable that the lamp supporting member has a notch, that is, the light source lamp is supported by the lamp supporting member having segmented gripping shape having an opening in one part. Thus, the light source lamp may be mounted after the lamp supporting member is fixed. In this case, the lamp supporting member preferably supports the light source lamp up to the upper part as shown in
The present invention also relates to the lamp supporting member used in the illuminating device for a display device. The lamp supporting member is useful as a part which constitutes the illuminating device for a display device and more particularly, the illuminating device for a display device suitable for constituting a backlight of a transparent liquid crystal display device or a semi-transparent one having a transparent region in a liquid crystal element.
Furthermore, the present invention relates to a liquid crystal display device comprising the illuminating device for a display device. According to the liquid crystal display device, the operation and effect of improvement in display quality may be provided by prevention of lower luminance or unevenness of luminance, and when lamp supporting member has a plurality of structural parts for gripping the light source lamp, the liquid crystal display device may be effectively used for a display panel of a consumer video monitor, an industrial equipment monitor, and a Personal Digital Assistant as a transparent liquid crystal display or a semi-transparent one in which the number of parts is reduced, assembly variation in manufacturing steps is prevented, impact resistance is improved and power consumption is reduced.
Since the illuminating device for a display device and the lamp supporting member of the present invention have the above-mentioned constitutions, unevenness of luminance on the information display surface may be prevented by securing of the position precision of the light source lamp, and light leakage caused by the structure of the lamp supporting member is reduced, and the influence of lower luminance or the unevenness of luminance is reduced, so that excellent display quality may be provided. Especially, the illuminating device for a display device and the lamp supporting member of the present invention is suitable for the illuminating device which constitutes the backlight of the transparent liquid crystal display device or the semi-transparent one having the transparent region in the liquid crystal element. In addition, according to the liquid crystal display comprising the illuminating device for a display device of the present invention, the operation and effect such as improvement in display quality may be provided by prevention of the lower luminance or luminance unevenness, the number of parts is reduced, assembly fluctuation in manufacturing steps is prevented, impact resistance is improved and power consumption is reduced, which is effective as various kinds of monitors and display panels.
The preferred configurations of the illuminating device for a display device according to the present invention will, hereinafter, be described in more detail with reference to drawings based on the embodiments, but the present invention is not limited to the embodiments and the embodiments may be combined, for example.
In a liquid crystal display device having an illuminating device behind a liquid crystal display element, a white lamp supporting member which has a configuration for being able to support a fluorescent tube and is formed of insulation resin, is provided on high reflective resin of a display region, whereby the illuminating device in which the fluorescent tubes are arranged in parallel and equally spaced is constituted. In
According to this constitution, a defect caused by light leakage may be prevented, and displacement of the lamp may be controlled. Also since the lamp supporting member has a plurality of structural parts for gripping a light source lamp, the number of parts may be reduced. Therefore, a stable liquid crystal module having excellent display quality may be provided at low cost.
In this embodiment and the following embodiments, a shape, material, the number, and a position of the lamp supporting member made of insulation resin is not limited as long as a particular requirement of the present invention is satisfied. In addition, the liquid crystal display device may comprise either a direct backlight or an edge light (side backlight) having U-shaped lamp or even-numbered U-shaped lamps. In addition, as a direct type of liquid crystal display device comprising the illuminating device for a display device of the present invention, there is a liquid crystal display device having a structure in which the high reflective resin is arranged on the metal sheet, the U-shaped tube having an end part and the like covered with the insulation resin is arranged on the high reflective resin by the storage frame (lamp frame), and the diffuser, several kinds of sheets such as a diffusion sheet, a condenser lens, a polarized light selective reflection/transmission sheet, a protection/diffusion sheet and an electromagnetic wave shielding sheet (conductive sheet, ITO sheet), the liquid crystal panel element, the frame and the like are arranged on the diffuser.
Similar to Embodiment 1, display region of an illuminating device is constituted using a lamp supporting member.
According to these constitutions, a defect caused by light leakage may be prevented, and since the structural parts of lamp supporting member grip the light source lamp, the number of parts may be reduced. Therefore, a stable liquid crystal module having excellent display quality may be provided at low cost. According to the configurations shown in
Similar to Embodiment 1, display region of an illuminating device is constituted using a lamp supporting member. As shown in
According to this constitution, the fixing pin is provided apart from a position just under the light source lamp, and light leakage from the fixing pin may be further reduced by reflection of the pin for supporting a diffuser. Also since the structural parts of lamp supporting member grip the light source lamp, the number of parts may be reduced, therefore a stable liquid module having excellent display quality may be provided at low cost.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2004-181370 | Jun 2004 | JP | national |
