JP2657472B2 - Surface lighting device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface illumination device mainly used as a backlight of a liquid crystal display device.

[0002]

2. Description of the Related Art Conventionally, a surface illuminating device used as a backlight of a liquid crystal display device is made of a transparent resin such as acryl, and a light guide plate provided with a diffuse reflection layer comprising dot-shaped protrusions on one surface is provided with a reflecting plate and a light diffusing plate. And a light source is arranged at the edge of the light guide plate. Then, the light emitted from the light source is guided to the light guide plate from the side surface thereof, and is irregularly reflected by the irregular reflection layer of the light guide plate, so that the light diffusion plate illuminates the liquid crystal display device.

[0003]

In recent years, while liquid crystal display devices have been increasing in size, they have been desired to be light and thin. Accordingly, surface lighting devices have been required to be light and thin, and low Power consumption and cost reduction are also required.

However, in the conventional surface lighting device, since the light guide plate is used and the reflection plate and the light diffusion plate are laminated on the light guide plate, the light guide plate is limited in thickness and thickness due to the required thickness. There is.

As disclosed in Japanese Patent Application Laid-Open No. 3-111819, a light guide plate having a modified shape has been proposed. However, the use of a light guide plate cannot overcome the limitations of light weight and thinness. .

According to the present invention, there is provided a surface illuminating device which can eliminate the light guide plate, reduce the weight and thickness, and reduce the cost, and can sufficiently increase the luminance of the device with respect to the luminance of the light source and the uniformity of the luminance of the display surface. The main purpose is to

[0007]

Therefore, in order to achieve the above-mentioned main object, the invention according to claim 1 is, as shown in FIG. 2, an elongated housing having a light emitting portion 20 on one side of a housing 1. A light source 2; a diffuse reflection layer 3 extending to a bottom portion on a front side in a light emitting direction of the light source 2 and having a portion facing away from the light source 2 inclined upward; 4, a light diffusion layer 5 provided on the upper surface of the housing 1, and a long convex lens body 6 disposed close to the light emitting section 20 of the light source 2.

According to a second aspect of the present invention, in the first aspect of the present invention, the long shape of the convex lens body 6 is favorably realized, and the light condensing function on the side away from the light source 2 is also appropriate. Therefore, the convex lens body 6 is configured to be a plano-convex lens 61 having a flat surface facing the light source 2.

According to a third aspect of the present invention, in each of the first and second aspects of the present invention, the convex lens body 6 has an appropriate light-condensing function in relation to the light source 2.
Was brought into contact with the light emitting section 20 of the light source 2.

According to a fourth aspect of the present invention, in the third aspect of the invention, the light source 2 and the convex lens body 6 are integrated to support the convex lens body 6 and position the contact state between the convex lens body 6 and the light source 2. For good performance, the end of the reflector 7 covering the back of the light source 2 is bonded to the upper and lower portions of the convex lens body 6.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects of the present invention, a bright line or the like does not occur on the side near the light source 2 where light irradiation tends to be locally strong. In order to do so, a long strip-shaped non-reflection section 8 is provided immediately below the convex lens body 6 in the light emission direction.

According to a sixth aspect of the present invention, in order to easily form the non-reflective portion 8, the non-reflective portion 8 is formed of a black tape 80.

According to a seventh aspect of the present invention, in any one of the first to sixth aspects of the present invention, in order to prevent light emitted to the air layer 4 from leaking, a peripheral wall surrounding the air layer 4 is provided with a reflective wall surface. 9 was formed.

According to an eighth aspect of the present invention, in order to further reduce the leakage of light, the rear surface of the top plate 11 of the housing 1 and the outer side of the reflecting wall 9 are provided. The configuration is such that a belt-shaped reflecting surface 90 is provided.

According to a ninth aspect of the present invention, in any one of the first to eighth aspects of the present invention, the irregular reflection layer 3 is formed of a white reflective sheet 31 in order to easily and satisfactorily form the irregular reflection layer 3.
And a lens film 32 laminated on the upper surface thereof.

According to a tenth aspect of the present invention, in any one of the first to ninth aspects of the present invention, the light diffusion layer 4 is formed of a ground glass sheet 51, Film 52, 53, 5 to be laminated on
4.

[0017]

According to the first aspect of the present invention, the light guide plate, which has been conventionally required, is omitted, and the weight and thickness of the structure using the light guide plate are overcome, and the weight is increased as compared with the conventional case. And the thickness can be greatly reduced. Nevertheless, the diffuse reflection layer 3 in contact with the air layer 4 is tilted upward at a portion away from the light source 2, and the light emitted from the light source 2 is elongated by the long convex lens body 6 arranged close to the light emitting portion 20. Since the light is collected at a position distant from the light source 2, the light from the light source 2 can be evenly and sufficiently irradiated on the irregular reflection layer 3.

According to the second aspect of the present invention, the convex lens body 6 is provided.
Is constituted by a plano-convex lens 61 having a flat surface facing the light source 2, so that the long shape of the convex lens body 6 can be satisfactorily realized, and light from the light source 2 is collected at a position close to the light source 2. Without light, it is possible to effectively irradiate a part which is distant from the light source 2 and tends to be dark, and the light collecting function can be made appropriate.

According to the third aspect of the present invention, the convex lens body 6
Is brought into contact with the light emitting unit 20 of the light source 2, so that the light from the light source 2 can be effectively applied to a part that is away from the light source 2 and tends to be dark, and in relation to the light source 2, The light-collecting function can also be made appropriate.

According to the fourth aspect of the present invention, the light source 2 and the convex lens body 6 are integrally held by the reflector 7, so that the convex lens body 6 can be favorably supported and the convex lens body 6 can be supported.
And the light source 2 can be kept in good contact.

According to the fifth aspect of the present invention, the long belt-shaped non-reflection portion 8 provided immediately below the convex lens body 6 in the front of the light emission direction provides a light near the light source 2 where light irradiation tends to be locally strong. , Bright lines and the like can be prevented.

According to the sixth aspect of the present invention, the black tape 80
Thereby, the non-reflection portion 8 can be easily formed.

According to the seventh aspect of the present invention, the light incident laterally from the light source 2 and the irregular reflection layer 3 are formed by the reflecting wall surface 9.
It is possible to prevent the light irregularly reflected from leaking to the outside and improve the luminance.

According to the eighth aspect of the present invention, the belt-like reflecting surface 9 is provided.
0, the light is mainly diffusely reflected by the irregular reflection layer 3 and
The leakage of light guided upward toward can be reduced, and the luminance can be improved.

According to the ninth aspect of the present invention, the irregular reflection layer 3 can be easily and satisfactorily formed by the white reflection sheet 31 and the lens film 32 laminated on the upper surface thereof.

According to the tenth aspect of the present invention, the ground glass sheet 51 and the lens films 52, 5 to be laminated thereon are provided.
3, 54, the light diffusion layer 5 can be formed easily and satisfactorily.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, reference numeral 1 denotes a thin box-shaped housing, and a light source 2 having a light emitting section 20 on one side is disposed on one long side of the housing 1. This light source 2
Has a diameter of about several millimeters, for example, 2.0 mm
And a long cold-cathode tube lamp.

At the bottom on the front side of the light source 2 in the light emission direction, a portion away from the light source 2 is inclined upward in a curved shape via a short support 12 and a long support 13 made of a transparent acrylic rod. The diffused reflection layer 3 is disposed. As shown in FIG. 2, the irregular reflection layer 3 includes a white reflection sheet 31 and a lens film 32 laminated on the upper surface thereof. As the white reflective sheet 31, for example, a foamed polyester sheet RW188 sold by "Kimoto" or the like is appropriate. Also, the lens film 32
For example, 3M (3M) Fresnel lens film BEF-90B is suitable. However, since the lens film 32 has the front, back, vertical and horizontal directions of the film, as shown in FIG. 1, the rows of the small peaks are directed to the upper surface side and perpendicular to the axis of the light source 2. It is to be placed in.

On the upper surface of the irregular reflection layer 3, an air layer 4 for guiding the light irregularly reflected by the irregular reflection layer 3 toward the upper surface is provided. As shown in FIGS. 1 and 3, frame members 14 and 1 made of a transparent acrylic rod are provided on three sides of a peripheral portion surrounding the air layer 4.
5 and 16 are provided. And each frame 14, 15, 1
6, as shown in FIG. 3, a foamed polyester sheet RW made of the same material as the white reflection sheet 31 described above.
The narrow reflecting wall 9 composed of 188 or the like is formed by sticking. Further, as shown in FIG. 4, on the back surface of the top plate portion 11 that covers the upper surface of the housing 1,
On the outer three sides, a reflective surface 9 made of the same foamed polyester sheet RW188 cut out in a U-shaped band shape is provided.
0 is formed by sticking. A non-reflective surface 98 made of black tape or the like is formed on the back surface of the top plate 11 and on the upper portion of the light source 2.

On the upper surface of the air layer 4, as shown in FIG.
Opening window 110 cut out in the center of top plate 11 of housing 1
The light diffusion layer 5 having a size corresponding to the size is arranged. This light diffusion layer 5 is composed of one ground glass sheet 51 having a matte surface and three lens films 5 laminated on the front and back.
2, 53, 54. Two lens films 52 and 53 laminated on the upper surface of the ground glass sheet 51
For example, the upper layer 52 is made of a Fresnel lens film BEF-90A made by 3M, and the lower layer 53 is made of BEF-90B or the like. Are arranged in parallel with each other, and the respective rows of the mountains are arranged perpendicular to the axis of the light source 2 with the faces of the films 52 and 53 having the rows of the small mountains facing the opposite sides. Ground glass sheet 51
The lens film 54 laminated on the lower surface of the
-90B or the like, and the rows of the minute peaks are directed downward and perpendicular to the axis of the light source 2.

A long convex lens body 6 is arranged close to the light emitting section 20 of the light source 2. The convex lens body 6 includes the light source 2
Is formed by a plano-convex lens 61 whose opposite side is a flat surface. The material is formed of acrylic or the like. The flat surface on the back side of the convex lens body 6 is in contact with the light emitting section 20 of the light source 2.

The end of the reflector 7 covering the back of the light source 2 is attached to the upper and lower portions of the convex lens body 6 by bonding. As the reflector 7, for example, a film obtained by depositing silver on the inner surface of an aluminum sheet is used.

Immediately below the convex lens body 6 in the light emitting direction,
A long and narrow non-reflective portion 8 made of a black tape 80 is provided.

Thus, with the above configuration, the radius R of the convex lens body 6 at the nine measurement points shown in FIG.
2.5 mm (R2.5), 3.0 mm (R3.
0) and 3.5 mm (R3.5), and the respective luminances were measured. Table 1 shows the results. Comparing with the comparative example without the convex lens body 6, it can be understood that, in the case where the convex lens body 6 is provided, the brightness is improved, the variation in the brightness of each part is small, and the overall uniformity is improved.

[0035]

[Table 1]

As described above, R2.5, R3.0,
For each of R3.5 and without the convex lens, the luminance distribution on the center line H parallel to the axis of the light source 2 is shown in FIGS. 6, 8, 10 and 12, respectively. The luminance distribution on the center line V is shown in FIG. 7, FIG. 9, FIG. 11, and FIG. As is clear from the luminance distribution diagram, in the case where the convex lens body 6 is provided, the luminance is improved near the rising portion of the irregular reflection layer 3 which tends to be dark without the convex lens body 6. . 6, 8, and 1
In FIG. 12 and FIG. 12, there is a portion where the luminance is locally reduced at a specific position. This is due to the characteristics of the light source 2 and is a phenomenon that is not related to the presence or absence of the convex lens body 6. .

[0037]

According to the first aspect of the present invention, the light guide plate, which has been conventionally required, is omitted, so that the limitation of the weight and thickness reduction by the configuration using this light guide plate is overcome, and the present invention is compared with the conventional one. Therefore, the weight and thickness can be greatly reduced, but the diffuse reflection layer 3 in contact with the air layer 4 is tilted upward at a portion away from the light source 2, and the light emitted from the light source 2 is transmitted to the light emitting portion 20. A long convex lens body 6 arranged in close proximity
Therefore, the light from the light source 2 can be evenly and sufficiently radiated to the irregular reflection layer 3, and the brightness and the uniformity thereof can be improved.

According to the second aspect of the present invention, the convex lens body 6 is a plano-convex lens 6 having a flat surface 61 on the side facing the light source 2.
Since it is composed of 1, the elongated shape of the convex lens body 6 can be satisfactorily realized, and light can be effectively applied to a part that is distant from the light source 2 and tends to be dark, and the light-gathering function is also provided. It can be made appropriate and the luminance can be further improved.

According to the third aspect of the present invention, since the convex lens body 6 is brought into contact with the light emitting section 20 of the light source 2, the light from the light source 2 is distant from the light source 2 and tends to be dark. And the light-collecting function can be made appropriate in relation to the light source 2, thereby improving the luminance.

According to the fourth aspect of the invention, the light source 2 and the convex lens body 6 are integrally held by the reflector 7, so that the convex lens body 6 can be favorably supported and the convex lens body 6 and the light source 2 A good contact state can be maintained.

According to the fifth aspect of the present invention, the long belt-shaped non-reflection portion 8 provided immediately below the convex lens body 6 in the light emitting direction is close to the light source 2 where light irradiation tends to be locally strong. On the side, it is possible to prevent adverse effects such as the occurrence of bright lines.

According to the sixth aspect of the present invention, the non-reflective portion 8 can be easily formed by the black tape 80.

According to the seventh aspect of the present invention, the reflecting wall surface 9
As a result, the light incident laterally from the light source 2 and the irregular reflection layer 3
It is possible to prevent the light irregularly reflected from leaking to the outside and improve the luminance.

According to the eighth aspect of the present invention, the strip-shaped reflecting surface 90 can effectively prevent light leaking mainly from the irregular reflection layer 3 and being led to the light diffusion layer 5, thereby improving the luminance. .

According to the ninth aspect of the present invention, the irregular reflection layer 3 can be easily and satisfactorily formed by the white reflection sheet 31 and the lens film 32 laminated on the upper surface thereof.

According to the tenth aspect of the present invention, a ground glass sheet 51 and a lens film 52 laminated thereon are provided.
With 53 and 54, the light diffusion layer 5 can be formed easily and favorably.

[Brief description of the drawings]

FIG. 1 is a perspective view of the inside of a surface illumination device according to the present invention.

FIG. 2 is a cross-sectional view of the same-surface lighting device.

FIG. 3 is a plan view of a housing.

FIG. 4 is a rear view of the housing top plate.

FIG. 5 is a plan view showing luminance measurement points according to a nine-point measurement method.

FIG. 6 is a luminance distribution in a central portion parallel to the light source axis when a convex lens body of R2.5 is used.

FIG. 7 is a luminance distribution in a central portion perpendicular to the light source axis when a convex lens body of R2.5 is used.

FIG. 8 is a luminance distribution at the center parallel to the light source axis when a convex lens body of R3.0 is used.

FIG. 9 is a luminance distribution in a central portion perpendicular to the light source axis when a convex lens body of R3.0 is used.

FIG. 10 is a luminance distribution at the center parallel to the light source axis when a convex lens body of R3.5 is used.

FIG. 11 is a luminance distribution at the center perpendicular to the light source axis when a convex lens body of R3.5 is used.

FIG. 12 is a luminance distribution in a central portion parallel to a light source axis when a convex lens body is not used.

FIG. 13 is a luminance distribution in a central portion perpendicular to a light source axis when a convex lens body is not used.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1; Housing, 11; Top plate part, 2; Light source, 20; Light-emitting part, 3; Diffuse reflection layer, 31; White reflection sheet, 32; Lens film, 4; Air layer, 5; Light diffusion layer, 51; Sheet, 52, 53, 54; lens film,
6; convex lens body, 61; plano-convex lens, 7; reflector,
8; non-reflective portion, 80; black tape, 9; reflective wall surface, 9
0; reflective surface

Claims (10)

(57) [Claims] 1. A long light source (2) having a light emitting portion (20) on one side in a housing (1), and the light source (2) extends to the bottom on the front side in the light emission direction of the light source (2). ), A diffusely reflecting layer (3) having a portion inclined upward, an air layer (4) for guiding light diffusely reflected by the diffusely reflecting layer (3) toward the upper surface, and light provided on the upper surface of the housing (1). A surface illumination device comprising: a diffusion layer (5); and a long convex lens body (6) disposed close to a light emitting part (20) of the light source (2). 2. The surface illumination device according to claim 1, wherein the convex lens body is a plano-convex lens having a flat surface facing the light source. 3. The surface illumination device according to claim 1, wherein the convex lens body (6) is in contact with the light emitting part (20) of the light source (2). 4. The surface lighting device according to claim 3, wherein an end of the reflector (7) covering the back of the light source (2) is bonded to upper and lower portions of the convex lens body (6). 5. A long strip-shaped non-reflection portion (8) is provided immediately below the convex lens body (6) in the light emission direction.
The surface lighting device according to any one of claims 1 to 4. 6. A non-reflective portion (8) is provided with a black tape (80).
6. The surface illumination device according to claim 5, wherein the surface illumination device is formed by: 7. The surface illuminating device according to claim 1, wherein a reflecting wall (9) is formed in a peripheral portion surrounding the air layer (4). 8. The surface according to claim 7, wherein a strip-shaped reflection surface is provided on the back surface of the top plate portion of the housing and outside the reflection wall surface. Lighting equipment. 9. A diffuse reflection layer (3) comprising a white reflection sheet (31) and a lens film (3) laminated on an upper surface thereof.
The surface lighting device according to any one of claims 1 to 8, comprising: 10. A light-diffusing layer (5) comprising a ground glass sheet (51) and a lens film (52,
The surface lighting device according to any one of claims 1 to 9, comprising: (53, 54).