JP3437899B2 - Lighting equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lighting device for a display device that requires a thin type and high brightness.

[0002]

2. Description of the Related Art An illumination device used for a liquid crystal display device and arranged behind the liquid crystal display device is generally called a backlight device. A conventional edge light type backlight device will be described with reference to FIGS. FIG. 8 is an exploded perspective view of a conventional backlight device of a liquid crystal display device.

In the frame 1 of FIG. 8, the diffusion sheet 2, the prism sheet 3, the prism sheet 4, the diffusion sheet 5, the light guide plate 6 and the reflection sheet 7 are positioned so as to overlap each other.
Next, the lamp holder 8 holding the lamp of the tubular light source is inserted in the direction of arrow A. Finally, the back cover 9 is attached to the frame 1 at several positions (5 positions in FIG. 8) by tapping screws 1.
It is screwed by 0.

FIG. 9 is a plan view after the assembly of FIG. 8 is completed.

FIG. 10A is a sectional view taken along line BB of FIG. 9, and FIG. 10B is a sectional view taken along line CC of FIG. In FIG. 10, 1 is a frame, 2 is a diffusion sheet, 3 is a prism sheet, 4 is a prism sheet, and 5 is a diffusion sheet. 6 is a light guide plate, 7 is a reflection sheet, 8 is a lamp holder, 11 is a lamp, and 9 is a back cover.

As shown in FIG. 10, a lamp 11 is arranged at the end of the transparent light guide plate 6, and a lamp holder 8 is arranged so as to cover it. On the bottom surface (on the side of the reflection sheet 7) of the transparent light guide plate 6, a diffuse reflection pattern that becomes denser as the distance from the lamp 11 increases is provided, whereby the light flux from the lamp 11 is used as a diffusion surface light source and is transparent. Light guide plate 6
Can be ejected from the upper surface (on the side of the diffusion sheet 2 or the like). Further, in order to effectively use the light flux, the reflection sheet 7,
The diffusion sheets 2 and 5 and the prism sheets 3 and 4 are arranged. This makes it possible to provide a thin, high-quality, highly efficient backlight device.

The following members may be used for each member. The lamp 11 is a cold cathode fluorescent lamp, the reflection sheet 7 is a white PET film, the transparent light guide plate 6 is a mirror-finished acrylic plate, the diffusion sheets 2 and 5 are made of polycarbonate, and the prism sheets 3 and 4 are made of polyester or the like. It is a thin sheet. Prism sheet 3, 4
Is an optical sheet for strengthening the directivity of the emission brightness of the backlight in the front direction of the liquid crystal display device, which is a thin sheet arranged in a prism shape having a pitch of about 50 μm and an apex angle of about 90 degrees.

The diffusion sheets 2 and 5 and the prism sheets 3 and 4 may be used one by one, or two by two,
Sometimes two are used and one is used. A wave sheet may be used instead of the prism sheet. 8 to 10 show a case where two diffusion sheets and two prism sheets are used.

Although the light guide plate 6 is heavy and needs to be firmly fixed, in the conventional example shown in FIGS. 8 to 10, the flange X of the frame 1 is guided onto the diffusion sheets 2 and 5 and the prism sheets 3 and 4. The optical plate 6 is placed, the reflection sheet 7 and the back cover 9 are further covered, and the parts are fixed while being pressed by the back cover. The back cover 9 was screwed to the frame 1 by tapping screws 10 at several positions (5 positions in FIG. 8).

The edge light type backlight device may be of a one-lamp type or a two-lamp type depending on its application, and FIGS. 8 to 10 show a two-lamp type backlight device. In the case of the one-lamp type, a light source is arranged at one end of a transparent light guide, and a diffuse reflection pattern material corresponding to this is provided, and other configurations and principles are the same as those of the two-lamp type. .

[0011]

The conventional edge light type backlight device has the following problems.
Conventionally, a diffusion sheet 2, a prism sheet 3, a prism sheet 4, a diffusion sheet 5, a light guide plate 6 and a reflection sheet 7 are positioned so as to sequentially overlap with each other on a frame 1 for holding components, and a back cover 9 is added. They were fixing those parts while pressing.

The first problem is that the diffusion sheets 2 and 5 and the prism sheets 3 and 4 are pressed against the frame 1 at their outer peripheral portions directly through the light guide plate 6, so that the diffusion sheets 2 and 5 and the prism sheet are provided. 3 and 4, the diffusion sheets 2 and 5 and the prism sheets 3 and 4 are bent at the time of high temperature use due to the difference in the thermal expansion coefficient due to the difference in the materials of the light guide plate 6 and the frame 1. The deflection of the sheet was visible even through the panel, which was a problem for a liquid crystal display device.

The thermal expansion coefficient of each component is, for example, the frame 1
Diffusing sheet 2 and 5 because the material is a polycarbonate and ^{6.6 × 10 - 5 (1 /} ℃), the prism sheet 3,4
Since the material is a polyester 3 × 10 ^{- 5} (1 /
Since the material of the light guide plate 6 is acrylic, it is 8.5 × 1.
0 ^- a ⁵ (1 / ℃), there is a difference as described above.

The second problem is that the diffusion sheets 2 and 5 and the prism sheets 3 and 4 are pressed against the frame 1 at their outer peripheral portions directly through the light guide plate 6, so that an imbalance in pressure occurs. When the diffusion sheet or the prism sheet bends and is used as a liquid crystal display device, the deflection of the sheet can be seen even through the liquid crystal panel, which is a problem for the liquid crystal display device.

The present invention solves the above problems and provides an illuminating device which has good display quality, is easy to assemble, and is excellent in mass productivity.

[0016]

SUMMARY OF THE INVENTION The present invention is an edge light type illuminating device arranged behind a display device,
In a lighting device in which at least an optical component including a light source, a light guide plate, and an optical sheet is supported and fixed to a frame, the light guide plate is supported by the frame so that the light guide plate does not directly ride on the optical sheet. It is characterized by

Further, the present invention is characterized in that the light guide plate is supported by ribs formed on at least a part of the frame.

The operation of the above configuration will be described below.

Since the outer peripheral portions of the diffusion sheet and the prism sheet are not directly pressed through the light guide plate, the diffusion sheet, the prism sheet, the light guide plate and the frame have a difference in thermal expansion coefficient, and therefore the diffusion sheet is used at high temperature. The prism sheet does not bend.

Further, since the outer peripheral portion of the diffusion sheet or the prism sheet is not directly pressed through the light guide plate, the diffusion sheet or the prism sheet is not bent due to the imbalance of the pressure, and the sheet is passed through the liquid crystal panel. I can't see the deflection.

Therefore, it is possible to provide an illuminating device which has good display quality, is easy to assemble, and is excellent in mass productivity.

[0022]

DETAILED DESCRIPTION OF THE INVENTION

(Embodiment 1) Embodiment 1 of a backlight device which is a lighting device of a liquid crystal display device will be described with reference to FIGS.
FIG. 1 is an exploded perspective view of the backlight device according to the first embodiment.

In the frame 1 of FIG. 1, a diffusion sheet 2, a prism sheet 3, a prism sheet 4, a diffusion sheet 5, a light guide plate 6 and a reflection sheet 7 are sequentially positioned. Next, the lamp holder 8 holding the lamp of the tubular light source is inserted in the direction of arrow A. Finally, the back cover 9 is the frame 1
It is screwed with tapping screws 10 at several positions (5 positions in FIG. 1). The liquid crystal panel is attached to the lower side of the frame 1 (light emission direction) in FIG.

FIG. 2 is a plan view after the assembly of FIG. 1 is completed.

FIG. 3 (a) is a sectional view taken along the line DD of FIG.
(B) is a EE sectional view of FIG. 1 in FIG. 3 is a frame, 2 is a diffusion sheet, 3 is a prism sheet, 4
Also, the prism sheet and 5 are diffusion sheets. 6 is a light guide plate, 7 is a reflection sheet, 8 is a lamp holder, 11 is a lamp, and 9 is a back cover.

The diffusion sheets 2 and 5 are made of polycarbonate, and the prism sheets 3 and 4 are thin sheets made of polyester or the like.

The prism sheets 3 and 4 are optical sheets for strengthening the directivity of the light emission luminance of the backlight in the front direction of the liquid crystal display device, and are arranged in a prism shape having a pitch of about 50 μm and an apex angle of about 90 degrees. It is a thin sheet.

The diffusion sheets 2 and 5 and the prism sheets 3 and 4 may be used one by one, or two by two,
Sometimes two are used and one is used. A wave sheet may be used instead of the prism sheet.

As shown in FIG. 3, the lamp 11 is arranged at the end of the transparent light guide plate 6, and the lamp holder 8 is arranged so as to cover it. On the bottom surface of the transparent light guide plate 6 (on the side of the reflection sheet 7), a diffuse reflection pattern material that becomes denser as the distance from the lamp 11 increases is provided.
Can be emitted from the upper surface (side of the diffusion sheet 2 etc.) of the transparent light guide plate 6 as a diffusion surface light source.

In the first embodiment, the flange X of the frame 1
Is positioned so that the diffusion sheet 2, the prism sheet 3, the prism sheet 4, and the diffusion sheet 5 are overlapped with each other.
The light guide plate 6 and the reflection sheet 7 are positioned on the ribs Y of the frame 1. The step between the flange X and the rib Y of the frame 1 is larger than the total sheet thickness of the diffusion sheets 2 and 5 and the prism sheets 3 and 4. In addition, the diffusion sheet 2,
The outer shapes of the prism sheet 5 and the prism sheet 3 and 4 are provided with a clearance between the rib Y and the rib Y so as not to hit the rib Y in consideration of the expansion of each component when used at high temperature.

Specifically, the optical sheets of the diffusion sheets 2 and 5 and the prism sheets 3 and 4 each have a thickness of 0.2 mm.
The total thickness is about 0.8 mm. The clearance between the diffusion sheet 5 and the light guide plate 6 is also about 0.2 mm. In addition, the diffusion sheets 2 and 5, the prism sheets 3 and 4, and the rib Y
The clearance around and is about 0.5 mm. In this case, the height of the rib Y is about 1 mm.

The height of the rib Y depends on the number of optical sheets, the thickness,
Although it depends on the material and the coefficient of thermal expansion, the clearance between the diffusion sheet 5 and the light guide plate 6 and the clearance around the diffusion sheets 2 and 5, the prism sheets 3 and 4 and the rib Y are the same as above.

The material and thermal expansion coefficient of each component are determined by the frame 1
Diffusing sheet 2 and 5 because the material is a polycarbonate and ^{6.6 × 10 - 5 (1 /} ℃), the prism sheet 3,4
Since the material is a polyester 3 × 10 ^{- 5} (1 /
Since the material of the light guide plate 6 is acrylic, it is 8.5 × 1.
0 ^{- 5} was (1 / ° C.), there is a difference as above, but considering the elongation, since a gap, there is no problem in deformation such as bending.

Further, the back cover 9 is covered, and the above components are fixed while being pressed by the back cover 9.

In the description of FIGS. 1 to 3, the rib Y is provided along the inner circumference of the frame 1, but as shown in FIG. 4, the rib Y is the center of the corner and side of the inner circumference of the frame 1. It may be provided in. The DD cross section and the EE cross section of the frame 1 are the same as those in FIGS.

Since the rib Y is provided on a part of the inner circumference of the frame 1, the diffusion sheet and the prism sheet do not bend during high temperature use due to the difference in thermal expansion coefficient.

Further, since the outer peripheral portion of the diffusion sheet or the prism sheet is not directly pressed through the light guide plate, the diffusion sheet or the prism sheet does not bend due to the imbalance of the pressure, and the sheet is passed through the liquid crystal panel. I can't see the deflection. Further, the weight of the lighting device can be reduced.

(Second Embodiment) A second embodiment of a backlight device, which is a lighting device of a liquid crystal display device, will be described with reference to FIGS. FIG. 5 is an exploded perspective view of the backlight device according to the second embodiment.

In the frame 1 of FIG. 5, a diffusion sheet 2, a prism sheet 3, a prism sheet 4, a diffusion sheet 5, a light guide plate 6, a reflection sheet 7 and a lamp holder 8 holding a lamp of a tubular light source are positioned one after another. It Finally, the light guide plate 6 and the lamp holder 8 are screwed to the frame 1 by tapping screws 10 at several positions (6 positions in FIG. 5).
The reflection sheet 7 is adhesively fixed to the outer periphery of the light guide plate 6 with a double-sided tape. The liquid crystal panel is attached to the lower side of the frame 1 (light emission direction) in FIG.

FIG. 6 is a plan view after the assembly of FIG. 5 is completed.

FIG. 7A is a sectional view taken along line FF in FIG.
(B) is a GG sectional view of FIG. In FIG. 7, 1 is a frame, 2 is a diffusion sheet, 3 is a prism sheet, 4
Also, the prism sheet and 5 are diffusion sheets. 6 is a light guide plate, 7 is a reflection sheet, 8 is a lamp holder, and 11 is a lamp.

The diffusion sheets 2 and 5 are made of polycarbonate, and the prism sheets 3 and 4 are thin sheets made of polyester or the like.

The prism sheets 3 and 4 are optical sheets for strengthening the directivity of the emission brightness of the backlight in the front direction of the liquid crystal display device, and are arranged in a prism shape having a pitch of about 50 μm and an apex angle of about 90 degrees. It is a thin sheet.

The diffusion sheets 2 and 5 and the prism sheets 3 and 4 may be used one by one, or two by two,
Sometimes two are used and one is used. A wave sheet may be used instead of the prism sheet.

As shown in FIG. 7, a lamp 11 is arranged at the end of the transparent light guide plate 6, and a lamp holder 8 is arranged so as to cover it. On the bottom surface of the transparent light guide plate 6 (on the side of the reflection sheet 7), a diffuse reflection pattern material that becomes denser as the distance from the lamp 11 increases is provided.
Can be emitted from the upper surface (side of the diffusion sheet 2 etc.) of the transparent light guide plate 6 as a diffusion surface light source.

In the second embodiment, the flange X of the frame 1
Are positioned so that the diffusion sheet 2, the prism sheet 3, the prism sheet 4 and the diffusion sheet 5 overlap with each other.
The light guide plate 6 and the reflection sheet 7 are positioned on the ribs Y of the frame 1. The step between the flange X and the rib Y of the frame 1 is larger than the total sheet thickness of the diffusion sheets 2 and 5 and the prism sheets 3 and 4. In addition, the diffusion sheet 2,
The outer shapes of the prism sheet 5 and the prism sheets 3 and 4 are provided with a clearance between the rib Y and the rib Y so as not to hit the rib Y, considering the expansion of each component when used at high temperature.

Specifically, the optical sheets of the diffusion sheets 2 and 5 and the prism sheets 3 and 4 each have a thickness of 0.2 mm.
The total thickness is about 0.8 mm. The clearance between the diffusion sheet 5 and the light guide plate 6 is also about 0.2 mm. In addition, the diffusion sheets 2 and 5, the prism sheets 3 and 4, and the rib Y
The clearance around and is about 0.5 mm. In this case, the height of the rib Y is about 1 mm.

The height of the rib Y depends on the number of optical sheets, the thickness,
Although it depends on the material and the coefficient of thermal expansion, the clearance between the diffusion sheet 5 and the light guide plate 6 and the clearance around the diffusion sheets 2 and 5, the prism sheets 3 and 4 and the rib Y are the same as above.

The material of each part and the coefficient of thermal expansion are determined by the frame 1
Diffusing sheet 2 and 5 because the material is a polycarbonate and ^{6.6 × 10 - 5 (1 /} ℃), the prism sheet 3,4
Since the material is a polyester 3 × 10 ^{- 5} (1 /
Since the material of the light guide plate 6 is acrylic, it is 8.5 × 1.
0 ^{- 5} was (1 / ° C.), there is a difference as above, but considering the elongation, since a gap, there is no problem in deformation such as bending.

Further, the light guide plate 6 and the lamp holder 8 are
It is screwed to the frame 1 by tapping screws 10 at several places (6 places in FIG. 5).

Similar to the frame 1 of FIG. 4 described in the first embodiment, the ribs Y may be provided at the corners of the inner periphery of the frame 1 and the centers of the sides.

The edge light type backlight device described in Embodiments 1 and 2 is a two-light type backlight device. Depending on the application, there are one-light type and two-light type. In the case of the one-light type, a light source is arranged at one end of a transparent light guide, and a diffuse reflection pattern object corresponding to this is applied. Other configurations and principles are similar to those of the above-mentioned two-light type backlight device.

[0053]

The diffusion sheets 2 and 5 and the prism sheet 3,
In No. 4, since the outer peripheral portion is not directly pressed through the light guide plate 6, the diffusion sheets 2, 5 and the prism sheets 3, 4 and the light guide plate 6 and the frame 1 have different thermal expansion coefficients, and therefore, The diffusion sheets 2 and 5 and the prism sheets 3 and 4 do not bend.

Further, since the outer peripheral portions of the diffusion sheets 2 and 5 and the prism sheets 3 and 4 are not directly pressed via the light guide plate 6, the diffusion sheets 2 and 5 are unbalanced due to the imbalance of pressure.
The prism sheets 3 and 4 do not bend, and the bending of the sheets cannot be seen even through the liquid crystal panel.

Therefore, it is possible to provide an illuminating device which has good display quality, is easy to assemble, and is excellent in mass productivity.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a backlight device according to a first embodiment.

FIG. 2 is a plan view of the backlight device of the first embodiment after assembly.

3A is a sectional view taken along the line DD of FIG. 2, and FIG. 3B is a sectional view taken along the line EE of FIG.

FIG. 4 is a perspective view of the frame 1 in which ribs Y are provided at the corners of the inner periphery of the frame 1 and in the centers of the sides.

FIG. 5 is an exploded perspective view of the backlight device according to the second embodiment.

FIG. 6 is a plan view of the backlight device according to the second embodiment after assembly.

7A is a sectional view taken along line FF in FIG. 6, and FIG. 7B is a sectional view taken along line GG in FIG.

FIG. 8 is an exploded perspective view of a conventional two-light type backlight device.

FIG. 9 is a plan view after assembly of a conventional two-light type backlight device.

10A is a sectional view taken along line BB of FIG. 9, and FIG.
It is CC sectional drawing of.

[Explanation of symbols] 1 frame 25 diffusion sheet 3 4 prism sheet 6 Light guide plate 7 Reflective sheet 8 lamp holder 9 back cover 10 tapping screws 11 lamps X flange Y rib

Continuation of the front page (56) Reference JP-A-8-64021 (JP, A) JP-A-8-68998 (JP, A) JP-A-8-136920 (JP, A) JP-A-8-240719 (JP , A) JP-A-7-20464 (JP, A) JP-A-6-167617 (JP, A) JP-A-9-127895 (JP, A) Actually open 4-40409 (JP, U) (58) Fields surveyed (Int.Cl. ⁷ , DB name) G09F 9/00 G02F 1/13357 G02F 1/1335 F21V 8/00

Claims (2)

(57) [Claims] 1. An illuminating device of an edge light type arranged behind a display device, comprising at least a light source, a light guide plate,
In an illuminating device in which an optical component including an optical sheet is supported and fixed to a frame, the light guide plate is supported by the frame so that the light guide plate does not directly ride on the optical sheet. Lighting equipment. 2. The lighting device according to claim 1, wherein the light guide plate is supported by ribs formed on at least a part of the frame.