JP3505807B2 - 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 example, a lighting device used as a backlight of a liquid crystal display device.

[0002]

2. Description of the Related Art For example, some liquid crystal display devices are provided with an illuminating device as a backlight on the back surface side of the liquid crystal display panel because the liquid crystal display panel itself does not have a self-luminous ability. FIGS. 6A and 6B show an example of such a conventional lighting device. In this lighting device, a light diffusing plate 2 is provided on a case 1, and a liquid crystal display panel (not shown) is provided on the light diffusing plate 2. The case 1 has a hollow structure, a display opening 3 is provided in a portion corresponding to the display area of the liquid crystal display panel on the upper surface, and a light source and other storage opening 4 is provided at one end. . A reflector 5 is provided on the lower side of the case 1, and a linear light source 6 is provided on the reflector 5. In this case, the linear light source 6 is composed of a U-shaped linear light source in which straight pipe portions 8 are connected to both ends of the curved pipe portion 7, respectively.
Then, when the linear light source 6 is turned on, the light from the linear light source 6 is diffused by the light diffusing plate 2 together with the light reflected by the reflecting plate 5, and the diffused light is applied to the back surface of the liquid crystal display panel. It will be.

By the way, in such an illuminating device, when the light diffusing plate 2 has a uniform diffusing function,
It is not possible to sufficiently prevent uneven brightness on the light diffusion plate 2 due to uneven brightness of the linear light source 6. That is,
In the portion along the line XX in FIG. 6A, the luminance in the portion corresponding to the straight tube portion 8 of the linear light source 6 becomes higher than that in the other portion, as shown by the solid line in FIG. 7A. Further, in the portion along the line YY of FIG. 6A, as shown by the solid line in FIG. 7B, the luminance of the portion corresponding to the curved tube portion 7 of the linear light source 6 is higher than that of the other portions. Get higher

[0004]

The present invention is directed to a display panel, a light diffusing plate arranged on the back surface of the display panel, a linear light source for irradiating light from the back surface of the light diffusing plate, and a housing for the linear light source. And a linear light source having a curved tube portion and at least a plurality of straight tube portions, wherein the light source housing portion includes the linear light source. A recess having a concave surface formed on the bottom surface for housing, a ridge line portion provided at a position corresponding to the central portion between the straight pipe portions of the linear light source, and each straight pipe portion side from the ridge line portion. An inclined surface that descends toward, and the light reflection portion,
A first reflective layer provided on an inner surface of the recess including a recessed surface of the light source housing, and a second reflective layer provided on at least a part of the inclined surface near the ridge, The first reflection layer irradiates the entire back surface of the light diffusion plate with reflected light, and the second reflection layer is formed on the back surface of the light diffusion plate.
The reflected light is emitted toward the outer peripheral portion outside the region between the straight tube portions of the linear light source.

[0005]

However, in such a conventional illuminating device, as shown by a dotted line in FIG. 7 (A), the linear light source 6 corresponds to the both straight tube portions 8, the vicinity thereof and the area between them. Although it is possible to mitigate the brightness unevenness in the portion, there is a problem that the brightness in the portion of the linear light source 6 corresponding to the outside of the straight tube portion 8 is not improved and becomes lower than the other portions. In addition, there is a problem that the brightness in the square of the light diffusing plate 2 (that is, the square in the display area of the liquid crystal display panel) is inevitably lower than that of other portions. An object of the present invention is to provide a lighting device capable of making the brightness even more uniform throughout.

[0006]

The present invention is directed to a display panel, a light diffusing plate arranged on the back surface of the display panel, a linear light source for irradiating light from the back surface of the light diffusing plate, and a housing for the linear light source. And a linear light source having a curved tube portion and at least a plurality of straight tube portions, wherein the light source housing portion is a linear light source. Each of the light pipes has an inclined surface that descends from a position corresponding to the central portion between the pipe parts toward the respective straight pipe parts, and the light reflection portion includes a first reflection layer and a second reflection layer, The first reflection layer irradiates reflected light toward a predetermined range on the back surface of the light diffusion plate, and the second reflection layer is the amount of light irradiated from the linear light source to the back surface of the light diffusion plate, The light is reflected toward a portion smaller than a predetermined amount.

[0007]

According to the present invention, since the second reflection layer reflects the amount of light emitted from the linear light source to the back surface of the light diffusion plate toward a portion smaller than a predetermined amount, the relative amount is reduced. It is possible to lighten the outer peripheral portion that becomes darker, and thus to make the brightness even more uniform throughout.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a main part of a lighting device according to an embodiment of the present invention. This illuminating device includes a reflector / case 21, a linear light source 31, a light diffusion plate 41, and the like. Of these, the linear light source 31 is composed of a U-shaped linear light source in which straight pipe portions 33 are continuously provided at both ends of the curved pipe portion 32. A base 34 is provided.

As shown in FIG. 2, the reflector / case 21 also has a rectangular light source accommodating recess 22, a U-shaped concave surface 23 formed on the inner bottom surface of the light source accommodating recess 22, and the concave surface. A mouthpiece storage portion 24 formed by penetrating in the vicinity of both end portions of 23, the mouthpiece storage portion 24 and the light source storage recess 22.
A structure including a light diffusing plate housing portion 25 formed around the light source plate, a light source locking piece 26 formed to project at a predetermined portion of the concave surface 23, and the like, and an inner surface of the light source housing concave portion 22 including the concave surface 23. Is provided with a reflective film (first reflective layer, not shown) made of a white paint film. The portion of the concave surface 23 corresponding to the both straight tube portions 33 of the linear light source 31 is a straight ridge line portion 23a corresponding to the central portion between the both straight tube portions 33, and both sides of the ridge line portion 23a are straight. The curved surface 23b is curved in a direction corresponding to the radial direction of the tube portion 33. That is, the portion of the concave surface 23 corresponding to the both straight tube portions 33 of the linear light source 31 has an inclined surface that descends from the position corresponding to the central portion between the both straight tube portions 33 toward the respective straight tube portions 33. Have

A reflection sheet (second reflection layer) 27 is attached to each predetermined portion of both curved surfaces 23b in the vicinity of the ridge 23a of the concave surface 23. The reflection sheet 27 is
The metal foil is made of Al, Ni, Ag, or the like, or the base film is formed by applying Al, Ni, Ag, or the like by vapor deposition, sputtering, or the like. This reflection sheet 27 is
As a matter of course, the concave surface 23 is curved along the curved surface 23b. Then, when the linear light source 31 is housed in the concave surface 23 and the both cap housing portions 24 and the linear light source 31 is turned on, the light from the linear light source 31 is diffused by a reflection film (first reflection layer) not shown. The light from each straight pipe portion 33 of the linear light source 31 is reflected by a predetermined range on the back surface of the plate 41, and as shown by the alternate long and short dash line in FIG. The light is reflected toward the outside of 33, that is, toward the predetermined two opposite sides (outer peripheral portions) of the light source housing recess 22.

Next, the light diffusing plate 41 will be described with reference to FIGS.
This will be described with reference to (C). The light diffusion plate 41 is formed of a material (for example, a resin material colored in milky white) whose light transmittance can be changed by changing the plate thickness, and has a rectangular flat plate portion 42, and the flat plate portion 42. A flat U-shaped undulating portion 43 formed on the back surface (or front surface),
A mouthpiece retainer piece 44 formed to project at two predetermined positions on the back surface of one end of the flat plate portion 42 in the vicinity of both ends of the undulating portion 43, and a flat plate portion 42 near the mouthpiece retainer piece 44.
The structure is provided with light leakage prevention pieces 45 formed so as to project at two predetermined positions at one end of the.

The undulating portion 43 is the straight tube portion 3 of the linear light source 31.
A portion corresponding to the central portion of 3 is a linear valley portion 43a, and a U-shape corresponding to the shape of the linear light source 31 outside the valley portion 43a and smaller than the shape of the linear light source 31 by a predetermined amount. The ridge line portion 43b is formed, and the periphery of the ridge line portion 43b and the like is a skirt portion 43c. Also, the valley portion 43a
The ridge line portion 43b is formed so as to be gradually higher from the side corresponding to the base 34 of the linear light source 31 toward the side corresponding to the curved pipe portion 32. Further, the valley portion 43a has a curved concave surface shape, and the ridge line portion 43b has a curved convex surface shape. The reason why the undulating portion 43 has such a shape is that the light transmittance is different due to the difference in plate thickness.
This is for alleviating the uneven brightness on the light diffusion plate 41 due to the uneven brightness of the linear light source 31.

As shown in FIG. 1, the light diffusing plate 41 is housed in the light diffusing plate housing part 25 of the reflector / case 21 with the undulations 43 facing down. In this case, the central portion of the curved tube portion 32 of the linear light source 31 is detachably locked to the locking piece 26 at a predetermined position on the inner bottom surface of the light source housing recess 22 of the reflector / case 21 and the base is 34 is a mouthpiece storage part 2
It is stored in 4. The cap pressing piece 44 is the cap 3
By pressing 4, the linear light source 31 is fixedly housed in the light source housing recess 22 of the reflector / case 21. Further, the light leakage prevention piece 45 covers the mouthpiece storage portion 24 of the reflector / case 21 to prevent light from leaking therefrom.

[0014]

As described above, according to the present invention, the outer peripheral portion of the back surface of the light diffusing plate outside the area between the straight tube portions of the linear light source is provided by the second reflecting layer. Since the reflected light is radiated toward, it is possible to make the outer peripheral portion, which becomes relatively dark, brighter, and thus to make the luminance even more uniform throughout.

Next, FIG. 5 shows a main part of an illuminating device according to another embodiment of the present invention. In this example,
The concave surface 23 is curved in a direction corresponding to the radial direction of the straight tube portion 33 of the linear light source 31, and is a portion corresponding to both sides of the straight tube portion 33 of the linear light source 31 in the longitudinal direction substantially at the center. In, the linear light source 31 is curved in a direction corresponding to the lengthwise direction of the straight tube portion 33, and therefore the reflection sheet 27 is also curved. Therefore, the light from each straight pipe portion 33 of the linear light source 31 causes the light from the straight pipe portion 33 of the linear light source 31 to be reflected by the reflection sheet 27 in the portion curved in the direction corresponding to the length direction of the straight pipe portion 33 of the linear light source 31. Of the light diffusing plate 41 (that is, the square of the liquid crystal display panel display area), and the luminance can be made approximately the same as that of the other portions. The shape of the linear light source is not limited to the U shape, but may be a W shape or the like.

[0016]

As described above, according to the present invention, the second reflecting layer reflects the light emitted from the linear light source to the back surface of the light diffusing plate toward a portion where the amount of light is less than the predetermined amount. Therefore, the relatively dark outer peripheral portion can be brightened, and thus the luminance can be made more uniform over the entire area.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a main part of a lighting device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along the line AA in FIG. 1 of a case that also serves as a reflector of this lighting device.

FIG. 3A is a perspective view of the light diffusing plate of the lighting device viewed from the back side, and FIG. 3B is a cross-sectional view taken along the line BB.
(C) is sectional drawing which follows the CC line.

FIG. 4 is a diagram shown for explaining the luminance of a portion along the line AA in FIG.

FIG. 5 is an exploded perspective view of a main part of a lighting device according to another embodiment of the present invention.

FIG. 6A is a plan view of an example of a conventional lighting device,
FIG. 7B is a sectional view taken along the line YY.

7A is a diagram shown for explaining the luminance of a portion along the line XX in FIG. 6A, and FIG. 7B is a diagram showing Y- in FIG. 6A.
The figure shown in order to demonstrate the brightness | luminance of the part along a Y line.

FIG. 8 is a plan view showing another example of the light diffusion plate in the conventional lighting device.

[Explanation of symbols]

21 Reflector and case 22 Light source storage recess 23 concave 27 Reflective sheet 31 linear light source 41 Light diffuser

Claims (5)

(57) [Claims] 1. A display panel, a light diffusing plate disposed on the back surface of the display panel, a linear light source that irradiates light from the back surface of the light diffusing plate, and a light source that houses the linear light source and has a light reflecting portion. An illumination device comprising a storage part, wherein the linear light source has a curved pipe part and at least a plurality of straight pipe parts, and the light source storage part has a concave surface on a bottom surface for storing the linear light source. The formed concave portion, the ridge line portion provided at a position corresponding to the central portion between the straight pipe portions of the linear light source, and the inclined surface that descends from the ridge line portion toward the straight pipe portion side. And the light reflecting portion is provided on at least a part of the first reflecting layer provided on the inner surface of the recess including the concave surface of the light source storage portion and on the inclined surface near the ridge portion. And a second reflective layer, wherein the first reflective layer covers the entire back surface of the light diffusion plate. And irradiate reflected light toward the outer periphery of the back surface of the light diffusion plate outside the region between the straight tube portions of the linear light source. Lighting device. 2. The lighting device according to claim 1, wherein the first reflective layer is a reflective film made of a white paint film. 3. The lighting device according to claim 1, wherein the second reflective layer is a reflective sheet. 4. The second reflective layer is curved in a direction corresponding to the radial direction of the straight tube portion of the linear light source, and has a length substantially at the center of the straight tube portion of the linear light source in the length direction. The lighting device according to claim 1, wherein the portions corresponding to both sides in the vertical direction are curved in a direction corresponding to the length direction of the straight tube portion of the linear light source. 5. The linear light source comprises a U-shaped linear light source in which the straight pipe portions are connected to both ends of the curved pipe portion, respectively. The lighting device according to any one of claims.