JP2004071167A - Flat-shaped light source device and liquid crystal display device using the same, and manufacturing method of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flat-shaped light source device restrained from the generation of emission line, and a liquid crystal display device, and manufacturing method of the same. <P>SOLUTION: The flat-shaped light source device comprises a lamp 6, a light guide plate 1 guiding the light from the lamp 6 to the whole surface, an optical sheet 2 arranged at a light emitting surface of the light guide plate 1, and a resin frame 4 housing the light guide plate 1 and the optical sheet 2. The emission line or unevenness of the display caused by the leakage of light between a lamp unit 5 and the light guide plate 1 can be restrained by sticking a light blocking tape 9 to a part or whole part of the edge part of the light emitting side of the light guide plate. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a side light type planar light source device, a liquid crystal display device using the same, and a method of manufacturing the same.
[0002]
[Prior art]
The liquid crystal display device includes a panel-shaped liquid crystal display element and a planar light source device provided on the back surface thereof. The surface light source device employs a side light (edge light) type backlight structure having a linear light source on the side surface. The configuration of a conventional planar light source device will be described with reference to FIGS.
[0003]
1 is a light guide plate, 2 is an optical sheet, 3 is a reflection sheet, 4 is a resin frame, 5 is a lamp unit, and 10 is a black frame portion. 6 is a lamp, 7 is a lamp reflector, 8 is a lamp cover, and these constitute the lamp unit 5. FIG. 10 is a perspective view of the planar light source device.
[0004]
The light guide plate 1 made of an acrylic resin or a polycarbonate resin guides light from the lamp unit 5 to the entire surface. An optical sheet 2 is provided on the light emitting surface side of the light guide plate 1. The optical sheet 2 includes a diffusion sheet, a protection sheet, a lens sheet, and the like. Among them, the diffusion sheet is provided closest to the light emitting surface. Light from the light guide plate 1 is uniformly diffused through the optical sheet 2 to the light emitting surface side where the liquid crystal display element (not shown) is provided. A reflection sheet 3 is provided on the back surface side of the light emitting surface of the light guide plate 1. As a result, light traveling to the opposite side to the light emitting surface is reflected by the reflecting sheet 3 toward the light emitting surface.
[0005]
Usually, a lamp unit 5 is provided on one side of the side surface of the light guide plate 1 as shown in FIG. Resin frames 4 are provided on the other three sides. As a result, the light guide plate 1, the optical sheet 2, and the reflection sheet 3 are housed, and constitute a planar light source device. FIG. 11 shows a cross section of the lamp unit 5 side.
[0006]
The lamp unit 5 is provided with a lamp 6 and a lamp reflector 7 for reflecting the light to the light guide plate 1, and is fixed with a lamp cover 8 as shown in FIG. For the sake of explanation, the light-emitting surface side will be referred to as the upper side, and the side opposite to the light-emitting surface will be referred to as the lower side.
[0007]
In such a side light type planar light source device, light leaks from a gap between the lamp unit 5 and the light guide plate 1 as shown by an arrow in FIG. As a result, there is a problem in that uneven brightness and uneven display (hereinafter, referred to as bright lines) in which the brightness increases at the end of the display area occur. Further, there is a problem that a gap is generated at an end of the display area due to variation, warpage, distortion, assembly accuracy, and the like of each component, an amount of light leakage increases, and a bright line is generated. In order to prevent this bright line, a black frame 10 was printed on the upper edge of the optical sheet 2 as shown in FIGS.
[0008]
However, the surface of the diffusion sheet provided on the upper side of the optical sheet 2 is uneven to diffuse light. Therefore, there is a problem that the adhesiveness of the paint on the printed black frame portion 10 is poor and the paint easily falls off. Further, a problem that a sufficient area for performing black frame printing cannot be ensured due to a narrow frame of the liquid crystal display device has arisen.
[0009]
This countermeasure is disclosed in JP-A-2001-117097 and JP-A-2001-91945. A planar light source device used in a liquid crystal display device disclosed in JP-A-2001-117097 will be described with reference to FIG. Further, a planar light source device used in the liquid crystal display device disclosed in JP-A-2001-91945 will be described with reference to FIG. 12 and 13 which are the same as those shown in FIGS. 10 and 11 have the same configuration, and a description thereof will be omitted. Here, 9 is a light-shielding tape.
[0010]
FIG. 12 is a cross-sectional view of the liquid crystal display device disclosed in JP-A-2001-117097 on the lamp unit 5 side. In Japanese Patent Application Laid-Open No. 2001-117097, the light-shielding tape 9 is provided only between the lamp reflector 7 and the light guide plate 1 as shown in FIG. Thereby, the generation of the bright line on the side where the lamp unit 5 is provided can be suppressed. However, since the light from the lamp 6 is reflected by the resin frame 4, a bright line may be generated on the side where the resin frame 4 is provided (the side other than the side where the lamp unit 5 is provided).
[0011]
Next, a side light type planar light source device of a liquid crystal display device disclosed in JP-A-2001-91945 will be described with reference to FIG. FIG. 13 is a sectional view on the resin frame 4 side of a planar light source device used in a liquid crystal display device disclosed in JP-A-2001-91945. In Japanese Patent Application Laid-Open No. 2001-91945, a light-shielding tape 9 is attached to the upper surface of a diffusion sheet above the optical sheet 2 as shown. The light-shielding tape 9 is provided all around the edge of the diffusion sheet. This makes it possible to suppress the occurrence of bright lines all around the display device. However, there is a problem that the diffusion sheet is too thin to be attached easily and the light-shielding tape 9 is shifted.
[0012]
[Problems to be solved by the invention]
As described above, the side light type planar light source device used in the conventional liquid crystal display device has a problem that it is not possible to suppress the generation of bright lines around the display area when the frame is narrowed. Was. There is also a problem that it is difficult to manufacture a planar light source device in which the generation of bright lines is suppressed.
[0013]
The present invention has been made in order to solve such a problem, and a first object of the present invention is to provide a planar light source device in which the generation of bright lines around the display area is suppressed and a display device using the same. Aim. It is a second object of the present invention to provide a method for easily manufacturing a planar light source device in which the generation of bright lines is suppressed.
[0014]
[Means for Solving the Problems]
The planar light source device according to the present invention includes a linear light source (for example, a lamp 6 in the embodiment of the present invention) and a light guide plate (for example, a light guide plate in the embodiment of the present invention) for guiding light from the linear light source to the entire surface. A light plate 1), an optical sheet (for example, the optical sheet 2 in the embodiment of the present invention) provided on the light-emitting surface side of the light guide plate, and a frame (for example, an embodiment of the present invention) for storing the light guide plate and the optical sheet. And a light-shielding tape (for example, a light-shielding tape 9 according to an embodiment of the present invention) is attached to an edge of the light guide plate on the light-emitting surface side. Thereby, the generation of the bright line can be suppressed.
[0015]
In the above-described planar light source device, the light-shielding tape may be extended on a side surface of the light guide plate. Thereby, the generation of the bright line can be suppressed.
[0016]
The surface light source device according to the present invention includes a linear light source, a light guide plate that guides light from the linear light source to the entire surface, an optical sheet provided on a light emitting surface side of the light guide plate, the light guide plate, and an optical sheet. A frame for accommodating a sheet, wherein a light-shielding tape is attached to an edge portion of the light guide plate on a light emitting surface side and a side surface of the light guide plate. Thereby, the generation of the bright line can be suppressed.
[0017]
In the above-described planar light source device, the linear light source may include a light emitting diode (for example, the light emitting diode 11 in the present embodiment) provided substantially in a line.
[0018]
The above-described planar light source device is preferably used for a display device. Further, it is desirable to use it for a liquid crystal display device. Thereby, display unevenness and luminance unevenness can be suppressed.
[0019]
The liquid crystal display device according to the present invention includes a light guide plate provided on the back surface side of the liquid crystal display element, a linear light source provided near at least one side of a side surface of the light guide plate, and a light emitting surface side of the light guide plate. An optical sheet provided, a frame for accommodating the light guide plate and the optical sheet are provided, and a light-shielding tape is attached to an edge of the light guide plate on a light emitting surface side. Thereby, the generation of the bright line can be suppressed.
[0020]
In the above-described liquid crystal display device, the light-shielding tape may be extended on a side surface of the light guide plate. Thereby, the generation of the bright line can be suppressed.
[0021]
The liquid crystal display device according to the present invention includes a light guide plate provided on a back surface side of a liquid crystal display element, a linear light source provided near at least one side of a side surface of the light guide plate, and a light emitting surface side of the light guide plate. The light guide plate and the frame that houses the optical sheet provided in the light guide plate, and a light-shielding tape is attached to an edge portion on the light emitting surface side of the light guide plate and a side surface of the light guide plate. Is what you do. Thereby, the generation of the bright line can be suppressed.
[0022]
In the liquid crystal display device described above, the linear light source may include a light emitting diode provided substantially in a line.
[0023]
The method for manufacturing a planar light source device according to the present invention includes a linear light source, a light guide plate that guides light from the linear light source over the entire surface, an optical sheet provided on a light emitting surface side of the light guide plate, A method for manufacturing a planar light source device comprising a light plate and a frame for accommodating an optical sheet, comprising a step of attaching a light-shielding tape to an edge portion of the light guide plate on a light emitting surface side. This makes it possible to easily manufacture a planar light source device in which the generation of bright lines is suppressed.
[0024]
In the above-described method for manufacturing a planar light source device, the linear light source may include light-emitting diodes provided substantially in a line.
[0025]
The method for manufacturing a liquid crystal display device according to the present invention includes: a light guide plate provided on a back surface side of a liquid crystal display element; a linear light source provided in proximity to at least one side of a side surface of the light guide plate; A method of manufacturing a liquid crystal display device, comprising: an optical sheet provided on the light emitting surface side of the light guide plate; and a frame accommodating the light guide plate and the optical sheet. It has a step of attaching a tape. This makes it possible to easily manufacture a liquid crystal display device in which the generation of bright lines is suppressed.
[0026]
In the above-described method for manufacturing a liquid crystal display device, the linear light source may include light-emitting diodes provided substantially in a line.
[0027]
BEST MODE FOR CARRYING OUT THE INVENTION
First Embodiment of the Invention
1, 2, and 3 show the structure of the planar light source device according to the first embodiment of the present invention. FIG. 1 is a perspective view of the planar light source device. FIG. 2 is a cross-sectional view of the side of the planar light source device where the resin frame is provided, and FIG. 3 is a cross-sectional view of the side where the lamp unit is provided. 1 is a light guide plate, 2 is an optical sheet, 3 is a reflection sheet, 4 is a resin frame, 5 is a lamp unit, and 9 is a light-shielding tape. 6 is a linear light source, 7 is a lamp reflector, 8 is a lamp cover, and these form the lamp unit 5.
[0028]
The light guide plate 1 made of acrylic resin, polycarbonate resin or the like guides light from the lamp unit 5 provided on one side surface to the entire surface. An optical sheet 2 is provided on the light emitting surface side of the light guide plate 1. A diffusion sheet is provided on the light emitting surface side of the optical sheet 2, and the optical sheet 2 is composed of a protective sheet, a lens sheet, and the like. Light from the light guide plate 1 is uniformly diffused through the optical sheet 2 to the light emitting surface side (upper side). A reflection sheet 3 is provided on the back side of the light guide plate 1. Thus, the light on the side opposite to the light emitting surface is reflected by the reflecting sheet 3 toward the light emitting surface.
[0029]
In the lamp unit 5, a lamp 6 as a linear light source and a lamp reflector 7 surrounding the outside of the lamp 6 are provided. Thereby, the light of the lamp 6 can be guided to the light guide plate 1 side. The lamp 6 and the lamp reflector 7 are fixed by a lamp cover 8. With such a structure, light can be emitted substantially uniformly. In addition, a resin frame 4 is provided on a side surface of the light guide plate where the lamp unit 6 is not provided to accommodate these components.
[0030]
The structure of the planar light source device according to the present invention is basically the same as that of the conventional planar light source device. However, the black frame portion is not printed, and the light guide plate 1 has a structure as shown in FIG. The difference is that a black light-shielding tape 9 made of PET (polyester) is attached to the entire periphery of the edge. When the light-shielding tape 9 is attached to the entire periphery of the light guide plate 1, the cross section is as shown in FIGS. Thereby, light leakage from the lamp unit 5 is suppressed, and generation of bright lines can be suppressed over the entire periphery of the display area.
[0031]
Further, since the light guide plate 1 is thicker than the optical sheet 2 such as a diffusion sheet, a tape can be easily attached and can be attached with higher accuracy. Thereby, the planar light source device in which the generation of the bright line is suppressed can be easily manufactured.
[0032]
The color of the light-shielding tape 9 described above is not limited to black as long as it absorbs light, and the material may be other than PET. One piece of tape may be attached to the entire circumference, or a plurality of light-shielding tapes 9 may be attached to cover the upper side of the edge of the light guide plate. Further, the light-shielding tape 9 may be a double-sided tape. Thereby, the light guide plate 1 and the optical sheet 2 are fixed, and a shift at the time of manufacturing can be suppressed. Therefore, a planar light source device in which the generation of bright lines is suppressed can be easily manufactured.
[0033]
Embodiment 2 of the invention
FIG. 5 shows the structure of the planar light source device according to the second embodiment of the present invention. 1, 2 and 3 denote the same components, and a description thereof will not be repeated. FIG. 5 is a sectional view of a side of the planar light source device on which the resin frame 4 is provided.
[0034]
The second embodiment differs from the first embodiment in that a light-shielding tape 9 is attached to the side surface of the light guide plate 1 as shown in FIG. As shown in FIG. 5, it is provided only on the side where the resin frame 4 is provided, and is not attached to the side where the lamp unit 5 is provided. Thus, light from the lamp unit 5 can be efficiently guided to the light guide plate 1, and the generation of bright lines around the display area can be suppressed. Further, it is possible to suppress the generation of the bright line due to the light leakage of the light reflected by the resin frame 4.
[0035]
The light-shielding tape 9 on the side surface may be a different tape from the light-shielding tape 9 on the display surface side of the light guide plate 1, or the same tape may be extended and attached. Further, as shown in FIG. 6, it may be attached to only a part of the side surface. When a different tape is attached, a tape of a different color or a different material may be used. Thereby, the planar light source device in which the generation of the bright line is suppressed can be easily manufactured.
[0036]
Embodiment 3 of the Invention
FIG. 7 shows the structure of the planar light source device according to the third embodiment of the present invention. 1, 2 and 3 denote the same components, and a description thereof will not be repeated. FIG. 7 is a cross-sectional view of a side of the planar light source device where the lamp unit 5 is provided.
[0037]
The third embodiment differs from the first or second embodiment in that the light-shielding tape 9 on the lamp unit 5 side is not provided up to the end of the light guide plate 1 and is inside the light guide plate 1. For example, here, the light-shielding tape 9 is not provided at a portion where the lamp reflector 7 and the light guide plate 1 overlap. Even if the light-shielding tape 9 is provided inside the edge of the light guide plate 1 as described above, light leakage can be blocked, and the same effect as that provided at the edge can be obtained.
[0038]
Other embodiments.
In the above-described embodiment, the planar light source device in which the light-shielding tape 9 is provided on the entire circumference of the light guide plate 1 is illustrated, but may be provided on only a part of the light guide plate 1 as shown in FIG. . For example, here, the light-shielding tape 9 is provided on about half of the side of the lamp unit 5 and both sides thereof. Similar effects can be obtained in such an embodiment. The same effect can be obtained if the light-shielding tape 9 is provided on a part of the edge of the light guide plate 1 without being limited to the illustrated form. In this case, the light-shielding tape 9 may be provided only at a portion where the bright line is frequently generated. Thereby, the light-shielding tape 9 can be saved, and the trouble of attaching the tape to the entire periphery can be saved.
[0039]
Also, the light-shielding tape 9 on the side surface of the light guide plate 1 described in the second embodiment may be provided not only on the entire circumference of the light guide plate 1 but also on a part thereof. Thereby, the generation of the bright line can be suppressed. In this case, the light-shielding tapes 9 on the upper and side surfaces of the light guide plate 1 may be provided at different locations.
[0040]
Further, the planar light source device according to the present invention may be a combination of the above-described embodiments. Further, the present invention is not limited to the illustrated embodiment, and a light-shielding tape may be provided on an edge of a light guide plate on which a lamp unit is not provided (on which a resin frame is provided) or on a part or all of the periphery of the edge. It is to be affixed. Thereby, generation of the bright line at the end of the display area can be suppressed. Further, a light-shielding tape may be attached to the side surface of the light guide plate where the lamp unit is not provided (the resin frame is provided). Thereby, it is possible to suppress the generation of the bright line at the end of the display area. Further, in the above-described embodiment, the lamp unit 5 is provided only on one side surface of the light guide plate 1, but is not limited thereto, and may be provided on two opposite side surfaces.
[0041]
Further, the light source used in the planar light source device according to the present invention may be other than the lamp 6. This embodiment is shown in FIG. FIG. 9 is a perspective view of a planar light source device using a light emitting diode as a light source. Since the same reference numerals as those shown in FIG. 1 indicate the same components, the description will be omitted. Reference numeral 11 denotes a light emitting diode (hereinafter, referred to as an LED). In this light emitting diode, a plurality of LEDs 11 of white or three colors of R, G, and B are arranged in substantially one row. The plurality of LEDs 11 emit white light as a linear light source.
[0042]
This embodiment is different from the above-described embodiment in that a plurality of LEDs 11 arranged substantially in a line are used instead of the lamp 6. Therefore, any of the above embodiments can be used, and the same effect can be obtained. Further, the linear light source may be other than the lamp 6 and a plurality of LEDs arranged substantially in a line.
[0043]
By using an LED element having high color reproducibility as a light source, a more beautiful display can be obtained. Further, by using LEDs having a longer life and higher luminous efficiency than the lamp 6, the frequency of replacement of the light source can be reduced.
[0044]
When such a planar light source device is used for a display device, a display device in which display defects such as display unevenness and luminance unevenness are suppressed can be obtained. Further, it is suitable for use in a liquid crystal display device. As a result, it is possible to suppress the occurrence of bright lines, display unevenness, and luminance unevenness of the liquid crystal display device.
[0045]
【The invention's effect】
According to the present invention, it has been made to solve such a problem, and it is possible to provide a planar light source device in which the generation of bright lines around the display area is suppressed and a display device using the same. . Further, it is possible to provide a method for easily manufacturing a planar light source device in which the generation of bright lines is suppressed.
[Brief description of the drawings]
FIG. 1 is a perspective view of a surface light source device according to a first embodiment of the present invention.
FIG. 2 is a cross-sectional view of the surface light source device according to the first embodiment of the present invention on a lamp unit side.
FIG. 3 is a cross-sectional view of the surface light source device according to the first embodiment of the present invention on a resin frame side.
FIG. 4 is a perspective view showing a state in which a light-shielding tape is attached to the planar light source device according to the present invention.
FIG. 5 is a cross-sectional view of the surface light source device according to the second embodiment of the present invention on the resin frame side.
FIG. 6 is a cross-sectional view of the surface light source device according to the second embodiment of the present invention on the resin frame side.
FIG. 7 is a cross-sectional view of a surface light source device according to a third embodiment of the present invention on a lamp unit side.
FIG. 8 is a perspective view of a planar light source device according to another embodiment of the present invention.
FIG. 9 is a perspective view of a planar light source device using a light emitting diode according to the present invention.
FIG. 10 is a perspective view of a conventional planar light source device.
FIG. 11 is a sectional view of a conventional planar light source device on a lamp unit side.
FIG. 12 is a sectional view of a conventional planar light source device on a lamp unit side.
FIG. 13 is a cross-sectional view of a conventional planar light source device on a resin frame side.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 light guide plate 2 optical sheet 3 reflection sheet 4 resin frame 5 lamp unit 6 lamp 7 lamp reflector 8 lamp cover 9 light-shielding tape 10 black frame 11 light-emitting diode (LED)

Claims (16)

A linear light source, and a light guide plate that guides light from the linear light source to the entire surface,
An optical sheet provided on the light emitting surface side of the light guide plate,
A frame that houses the light guide plate and the optical sheet,
A planar light source device, wherein a light-shielding tape is stuck over an edge portion of the light guide plate on a light emitting surface side and a lower portion of the optical sheet. The planar light source device according to claim 1, wherein the light-shielding tape extends on a side surface of the light guide plate. A linear light source,
A light guide plate that guides light from the linear light source to the entire surface,
An optical sheet provided on the light emitting surface side of the light guide plate,
A frame that houses the light guide plate and the optical sheet,
A planar light source device, wherein a light-shielding tape is independently applied to an edge portion of the light guide plate on a light emitting surface side and a side surface of the light guide plate. The planar light source device according to any one of claims 1 to 3, wherein the light-shielding tape is also attached to a side other than a side of the light guide plate provided with the linear light source. The planar light source device according to any one of claims 1 to 4, wherein the linear light source includes a light emitting diode arranged substantially in a line. A display device using the planar light source device according to claim 1. A liquid crystal display device using the planar light source device according to claim 1. A light guide plate provided on the back side of the liquid crystal display element,
A linear light source provided close to at least one side of the side surface of the light guide plate;
An optical sheet provided on the light emitting surface side of the light guide plate,
A frame that houses the light guide plate and the optical sheet,
A liquid crystal display device, wherein a light-shielding tape is stuck over an edge of the light guide plate on a light emitting surface side and a lower portion of the optical sheet. The liquid crystal display device according to claim 5, wherein the light-shielding tape extends on a side surface of the light guide plate. A light guide plate provided on the back side of the liquid crystal display element,
A linear light source provided close to at least one side of the side surface of the light guide plate;
An optical sheet provided on the light emitting surface side of the light guide plate,
A frame that houses the light guide plate and the optical sheet,
A liquid crystal display device, wherein independent light-shielding tapes are attached to an edge portion of the light guide plate on a light emitting surface side and a side surface of the light guide plate. The liquid crystal display device according to any one of claims 7 to 9, wherein the light-shielding tape is also attached to a side other than a side of the light guide plate provided with the linear light source. The liquid crystal display device according to any one of claims 8 to 11, wherein the linear light source includes a light emitting diode arranged substantially in a line. A linear light source,
A light guide plate that guides light from the linear light source to the entire surface,
An optical sheet provided on the light emitting surface side of the light guide plate,
A method for manufacturing a planar light source device including a frame that houses the light guide plate and the optical sheet,
A method for manufacturing a planar light source device, comprising a step of attaching a light-shielding tape over the optical sheet at an edge of the light guide plate on the light emitting surface side. 14. The method according to claim 13, wherein the linear light sources include light emitting diodes arranged in substantially one line. A light guide plate provided on the back side of the liquid crystal display element,
A linear light source provided close to at least one side of the side surface of the light guide plate;
An optical sheet provided on the light emitting surface side of the light guide plate,
A method for manufacturing a liquid crystal display device including a frame that houses the light guide plate and the optical sheet,
A method for manufacturing a liquid crystal display device, comprising a step of attaching a light-shielding tape over an optical sheet at an edge portion on a light-emitting surface side of the light guide plate. 16. The method according to claim 15, wherein the linear light sources include light emitting diodes arranged substantially in a line.

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