JP3982903B2 - LCD lighting device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an illumination device for a transmissive liquid crystal display device.
[0002]
[Prior art]
As shown in FIG. 7, a conventional liquid crystal lighting device has a structure in which a reflecting plate 8 is disposed under a light guide plate 7 having a diffusion pattern molded or printed on the lower surface thereof, and in the vicinity of an incident portion of the light guide 7. The tubular light source 6 is disposed, the reflecting plate 5 is disposed outside the tubular light source 6, and the diffusion sheet 4 is disposed on the light guide plate 7.
[0003]
A sheet 3 having a light collecting effect, a light deflection selective reflection / transmission sheet 2, a sheet 4 having a diffusion effect, a chassis 9 and a liquid crystal display panel 1 are disposed thereon. At this time, the clearance between the sheet 4 having a diffusion effect and the chassis 9 is 0.2 mm.
[0004]
[Problems to be solved by the invention]
In the case where an optical sheet having a large thermal shrinkage and a base substrate that is likely to be deformed by thermal stress is arranged in a liquid crystal display device, as shown in FIG. Wave-like deflection occurs in the sheet at the four sides of the sheet edge.
[0005]
This local deflection on the display is difficult to detect as long as it is observed from the front. However, this can be confirmed by observing from the top, bottom, left, and right sides. As shown in FIG. 9, when the clearance between the sheet 4 having a diffusion effect and the chassis 9 is 0.1 mm, the sheet is wavy on the upper portion of the liquid crystal display device at about 25 ° C. due to thermal factors of the light source. Although no deflection occurred, deflection occurred on the four sides of the sheet edge at 60 ° C., which could be detected by observation from the front.
[0006]
As shown in FIG. 10, when the side edges of all the sheets are fixed and the clearance between the sheet 4 having a diffusion effect and the chassis 9 is 0 mm, the liquid crystal display device has a temperature of about 25 ° C. due to thermal factors of the light source. At the top, no wavy deflection occurs on the sheet, but at 60 ° C., deflection occurs on the four sides of the sheet edge, which can be detected by observation from the front, which is larger than the case shown in FIG. It was.
[0007]
Further, when an optical sheet having a small thermal shrinkage and a base substrate which is not easily deformed by thermal stress is arranged in a liquid crystal display device, as shown in FIG. In the upper part of the apparatus, wavy deflection occurs on the sheet at the four sides of the sheet.
[0008]
The local deflection appearing on the display portion is difficult to detect as long as it is observed from the front. However, this can be confirmed by observing from the top, bottom, left, and right sides.
[0009]
As shown in FIG. 6, when the clearance between the sheet 4 having a diffusion effect and the chassis 9 is 0.1 mm, the sheet is placed on the upper part of the liquid crystal display device at about 25 ° C. due to thermal factors of the light source. Although wavy deflection did not occur, deflection occurred on the four sides of the sheet edge at 60 ° C., which could be detected by observation from the front.
[0010]
As shown in FIG. 7, when the side edges of the entire sheet are fixed and the clearance between the sheet 9 and the chassis 10 is 0 mm, the sheet is corrugated on the liquid crystal display at about 25 ° C. due to the thermal factor of the light source. However, at 60 ° C., deflection occurred on the four sides of the sheet edge, which could be detected by observation from the front, which was larger than that in FIG.
[0011]
The present invention detects an upper part of a liquid crystal display device due to a thermal factor when an optical sheet is placed on a liquid crystal display device as a liquid crystal lighting device and the base substrate is also easily deformed due to thermal stress. An object is to solve the occurrence of wavy deflection.
[0012]
[Means for Solving the Problems]
Liquid crystal lighting apparatus of the present invention, in the liquid crystal lighting apparatus having a lighting apparatus to the rear of the liquid crystal display panel, by pressing a substantially rectangular optical sheet, a substantially central portion of each side of the optical sheet held And a chassis to be provided .
[0013]
The present invention provides a liquid crystal lighting apparatus of the above configuration, the chassis has a curved portion, the chassis is characterized in that holding down the said optical sheet at the top of the curved portion.
[0014]
The present invention provides a liquid crystal lighting apparatus of the above construction, the chassis is characterized in that holding down the said optical sheet through a sheet-like or plate-like pressing member.
[0015]
According to the present invention, in the liquid crystal illumination device having the above-described configuration, the pressing member has a translucent color, a transparent color, or the same color as the chassis.
[0016]
Hereinafter, by the above configuration lever, while does not cause deflection of the central portion forces the deflection of wavy 4 corners of the liquid crystal display, the periphery bending also reduces.
Further, since the pressing member is semi-transparent color or transparent color or the same color as the chassis, it is difficult to detect deflection, and when a lighting device using such a configuration is incorporated in a liquid crystal display device, display quality is improved. Is not reduced.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below.
(Embodiment 1)
FIG. 1 is a sectional view showing a liquid crystal illumination device according to the first embodiment, and FIG. 2 is a partial sectional view of FIG. FIG. 6 is a diagram showing a display state of the liquid crystal illumination device according to the first embodiment.
[0018]
As shown in FIG. 1, a reflector 8 is disposed under the light guide 7. As the light deflection selective reflection / transmission sheet 2, for example, a sheet 4 having a diffusion effect is disposed on DBEF manufactured by 3M. The light deflection selective reflection / transmission sheet 2 has a function of selectively reflecting light without being absorbed by the lower deflection plate of the liquid crystal display device.
[0019]
The material of DBEF manufactured by 3M is made of polyethylene terephthalate (hereinafter referred to as PET), but is not limited to DBEF as long as it has the above function. In Embodiment 1, PC-03 manufactured by Ewa Shoko Co., Ltd. was used as the sheet 4 having a diffusion effect. The center end portion of DBEF is made of polycarbonate or glass fiber mixed resin, and has a structure in which the shape of the chassis 9 is curved and pressed locally.
[0020]
It is important to select a material having a low frictional resistance as a condition for selecting a material for forming the chassis 9 shape made of polycarbonate or a glass fiber mixed resin. The material used in 1 is not specified.
[0021]
When the above structure was realized, the clearance was 0 to +0.1 mm between the center of each sheet side and the chassis, and 0.2 mm between the sheet both ends and the chassis 9.
[0022]
(Embodiment 2)
FIG. 3 is a cross-sectional view showing a liquid crystal illumination device according to Embodiment 2, and FIG. 4 is a partial cross-sectional view of FIG. FIG. 5 is a partial cross-sectional view in which another part 10 (sheet or plate-like body) is installed on a member other than the chassis 9 of the liquid crystal lighting device according to the second embodiment.
[0023]
As shown in FIG. 3, the central portion of the side of the light deflection selective reflection / transmission sheet 2 is locally pressed by another part 10 (sheet or plate) and a curved molded product.
[0024]
At this time, the feature of the second embodiment is that the separate part 10 (sheet or plate-like body) and the curved molded product are bonded to the chassis 9 held close to the end of the sheet. This is a difference from the first embodiment.
[0025]
Other than that, DBEF manufactured by 3M was used as the light deflection selective reflection / transmission sheet 2 as in the first embodiment. Moreover, Ewa Shoko Co., Ltd. PC-03 was used as the sheet | seat 4 which has a spreading | diffusion effect. The center end portion of DBEF is made of polycarbonate or glass fiber mixed resin, and has a structure in which the shape of the chassis 9 is curved and pressed locally.
[0026]
A chassis 9 made of polycarbonate or glass fiber mixed resin was used. When the above structure was realized, the clearance was 0 to +0.1 mm between the center of each sheet side and the chassis 9, and the distance between both sheet ends and the chassis 9 was 0.2 mm or more.
[0027]
(Embodiment 3)
FIG. 3 is a cross-sectional view showing a liquid crystal display device according to Embodiment 3, and FIG. 4 is a partial cross-sectional view of FIG. FIG. 5 is a partial cross-sectional view in which another part 10 (sheet or plate-like body) is installed on members other than the chassis 9 portion of the liquid crystal display device according to the third embodiment. As shown in FIG. 3, the central portion of the side of the light deflection selective reflection / transmission sheet 2 is locally pressed by another part 10 (sheet or plate) and a curved molded product. At this time, the separate part 10 (sheet or plate-like body) and the curved molded product have the same color tone as the chassis 9 made of polycarbonate or glass fiber mixed resin held in proximity to the sheet end. In the third embodiment, black that matches the purpose of suppressing light reflection is adopted, but white may be adopted in the case of using light reflection in reverse.
[0028]
Moreover, even if it is other than black and white, it may be unified to the same color or transparent or translucent color tone.
[0029]
(Comparative Example 1)
FIG. 11 shows a state in which deflection occurs in the case where an optical sheet that does not easily deform due to thermal stress is used without pressing the sheet of Conventional Example 1 shown in FIG. The state after 30 minutes and 2 hours after is tracked.
[0030]
(Comparative Example 2)
FIG. 12 shows the state of deflection when the tubular light source 6 is used in the case where an optical sheet that hardly deforms against thermal stress is used under the condition that the sides of all the sheets of Conventional Example 2 are pressed as shown in FIG. The state after 30 minutes and 2 hours after lighting is tracked.
[0031]
(Comparative Example 3)
FIG. 13 shows the state of deflection when the tubular light source 6 is used in the case where an optical sheet that hardly deforms against thermal stress is used under the condition that the sides of all the sheets of Conventional Example 3 are fixed as shown in FIG. The state after 30 minutes and 2 hours after lighting is tracked.
[0032]
As described above, from the results of Comparative Examples 1 to 3, in the case of using an optical sheet that is not easily deformed against thermal stress, the occurrence of deflection is 30 minutes after the tubular light source 6 is turned on. Although the condition after 2 hours was improved, it was confirmed that the deflection could not be improved significantly unless the optical sheet fixing method was changed.
[0033]
【The invention's effect】
As described above, according to the liquid crystal display device of the present invention, whereas not such to generate a deflection of the central portion forces the deflection of wavy 4 corners of the liquid crystal display, an effect of the periphery bending also reduces .
[0034]
Further, since the pressing member is translucent, transparent, or the same color as the chassis, it is difficult to detect the deflection, and the effect of preventing the display quality from being deteriorated is achieved.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view according to a first embodiment of the present invention.
FIG. 2 is a partial cross-sectional view of the liquid crystal illumination device of FIG.
FIG. 3 is a sectional view according to a second embodiment of the present invention.
4 is a partial cross-sectional view of the liquid crystal illumination device of FIG. 3;
FIG. 5 is a cross-sectional view in which a sheet or a plate-like body is installed on members other than the chassis portion of the liquid crystal lighting device according to Embodiment 2 of the present invention.
6 is a diagram showing a display state of the liquid crystal illumination device of FIG. 1. FIG.
7 is a cross-sectional view of a liquid crystal illumination device according to prior art 1. FIG.
FIG. 8 is a diagram showing a display state of a liquid crystal illumination device according to prior art 1.
FIG. 9 is a diagram illustrating a display state of a liquid crystal lighting device according to the related art 2;
FIG. 10 is a diagram showing a display state of a liquid crystal lighting device according to prior art 3.
11 is a view showing a display state of a liquid crystal lighting device according to Comparative Example 1. FIG.
12 is a view showing a display state of a liquid crystal illumination device according to Comparative Example 2. FIG.
13 is a diagram showing a display state of a liquid crystal lighting device according to Comparative Example 3. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Liquid crystal display board 2 Light polarization selective reflection transmission sheet 3 Sheet | seat which has a condensing effect 4 Sheet | seat which has a diffusion effect 5 Reflecting plate 6 Tubular light source 7 Light guide body 8 Reflecting plate 9 Chassis 10 Separate parts (sheet shape or plate-shaped body) )

Claims (4)

In a liquid crystal lighting device having a lighting device behind the liquid crystal display panel,
A substantially rectangular optical sheet;
A chassis that holds and holds a substantially central portion of each side of the optical sheet ;
Liquid crystal lighting apparatus, comprising the.   The liquid crystal lighting device according to claim 1, wherein the chassis has a curved portion, and the chassis presses and holds the optical sheet at the top of the curved portion.   The liquid crystal illumination device according to claim 1, wherein the chassis presses and holds the optical sheet via a sheet-like or plate-like pressing member.
  4. The liquid crystal illumination device according to claim 3, wherein the pressing member is a translucent color, a transparent color, or the same color as the chassis.

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