JP2003195298A - Edge light type surface light emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an edge light type surface light emitting device not causing a bright spot or a bright line due to the projection part of a light transmission plate side face. <P>SOLUTION: For an edge light type surface light emitting device, a line light source is arranged on at least one of two opposing side faces of a light transmission plate composed of a transparent resin plate, a light scattering part is provided corresponding to the display area of a liquid crystal panel on the back surface of the light transmission plate in such a gradation pattern that an area rate is larger at a part away from the line light source than at the part near the line light source, and the two side faces forming the right angle with the side face where the line light source of the light transmission plate is arranged are provided with the projection part by projecting a part of the resin plate. On the back surface of the projection part, a light quantity adjustment part suppressing the quantity of light toward a projection part wall surface is provided. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin and lightweight laptop personal computer, word processor, PDA (Personal digit).
al assistant), a mobile computer, an edge light type surface emitting device suitable for a backlight of a liquid crystal TV, etc., in particular, an edge light type surface emitting device that does not generate bright spots or bright lines due to protrusions on the side surface of the light guide plate. The present invention relates to a surface emitting device.

[0002]

2. Description of the Related Art Conventionally, as an edge light type surface emitting device, a linear light source 2 is arranged on one side surface of a light guide plate 1 made of a transparent resin plate, and a display area 7 of a liquid crystal panel is provided on the back surface of the light guide plate 1. Corresponding to the above, there is one in which the light scattering portion 6 is provided in a gradation pattern such that the area ratio becomes larger at a position distant from the linear light source 2 than at the vicinity of the linear light source 2. The light scattering section 6 scatters and reflects the light guided from the linear light source 2 into the light guide plate 1, and directs a part of the light toward the front surface side of the light guide plate 1. 1 Light is evenly distributed on the surface.

By the way, the light guide plate 1 provided with the light scattering portion 6 on the back surface is formed by laminating optical sheets such as a diffusion sheet, and is housed in the chassis 4 together with a linear light source 2 such as a cold cathode tube (CFL). However, in the case of the large-sized light guide plate 1 as in the above-mentioned application, if it is simply accommodated without fixing it, the product may be dropped due to an impact such as a drop of the product, and may contact the linear light source 2 to be destroyed. (See FIG. 6), it becomes impossible to obtain a uniform luminance due to a positional shift or the like. Therefore, in order to prevent the light guide plate from falling off due to an impact such as a drop, a part of the resin plate is protruded from two side surfaces of the light guide plate 1 that are perpendicular to the side surface on which the linear light source 2 is arranged to form a protrusion portion 3 which is provided on the chassis 4. It was general to fit in the recessed portion 5 formed (see FIG. 7). The material used for the chassis 4 is a resin mixed with a white pigment so that the light emitted from the side surface of the light guide plate 1 where the linear light source 2 is not arranged is reflected to the light guide plate 1 side and the light can be used efficiently. Etc. are often used.

[0004]

However, the above-mentioned general protrusion 3 has a strip-like planar shape, and each protrusion 3 has a planar shape.
However, of the two wall surfaces parallel to the linear light source 2, even the light that reaches the wall surface on the side far from the linear light source 2 is emitted to the outside of the light guide plate 1 as it is. As a result, when the chassis 4 is made of a material such as a resin mixed with the white pigment as described above,
As shown in FIG. 9, the light emitted from the wall surface on the side farther from the line light source 2 of the two wall surfaces of the protruding portion 3 parallel to the line light source 2 is mainly on the wall surface of the recess 5 provided in the chassis 4. The light is scattered and reflected on one side, and a part of it is directed toward the front surface side of the light guide plate 1. Since the outer edge of the light scattering portion 6 is extremely close to the outer shape of the light guide plate 1 due to the narrowing of the frame of the liquid crystal panel in recent years, the scattering reflection is abnormally bright only in the vicinity of the protrusion 3 of the display area 7. There is a problem of generating a high bright spot.

Therefore, in order to prevent the generation of bright spots, of the two parallel wall surfaces of the protruding portion 3, the wall surface on the side far from the linear light source 2 is eliminated or the area is reduced, that is, the planar shape is 4 1 oval (see Figure 10),
A triangular shape, a trapezoidal shape, or the like, and chamfering a corner far from the linear light source 2 are also performed. By doing so, the strip-shaped protruding portion 3 totally reflects the light transmitted through the wall surface on the side farther from the linear light source 2 of the two parallel wall surfaces (see FIG. 11), and is then provided on the chassis 4. It is possible to suppress scattering and reflection mainly on the side of the linear light source 2 on the wall surface of the hollow portion 5. However, in this case, although it is no longer scattered and reflected directly from the wall surface of the chassis 4 into the display area 7, the newly increased total reflection light at the protrusion 3 is scattered and reflected by the gradation pattern, resulting in abnormal light emission. However, there is a problem that a bright line is generated.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the above problems and to provide an edge light type surface light emitting device in which bright spots and bright lines due to the protrusions on the side surface of the light guide plate are not generated.

[0007]

In order to achieve the above object, according to the present invention, a line light source is arranged on at least one of two opposing side surfaces of a light guide plate made of a transparent resin plate, and a liquid crystal is provided on the back surface of the light guide plate. The light scattering part corresponding to the display area of the panel is provided in a gradation pattern such that the area ratio becomes larger at a position farther from the linear light source than near the linear light source, and is perpendicular to the side surface of the light guide plate on which the linear light source is arranged. In an edge light type surface light-emitting device in which two side faces forming a part of a resin plate protrude to have a protrusion, a light amount adjusting part for suppressing the amount of light traveling toward the wall surface of the protrusion is provided on the back surface of the protrusion. As configured.

In the above structure, the light quantity adjusting portion provided on the back surface of the protruding portion is a light scattering layer or a light absorbing layer.

Further, in the structure in which the light quantity adjusting section is a light scattering layer, the light scattering layer provided on the back surface of the protrusion is the same as the light scattering section provided corresponding to the display area of the liquid crystal panel. The contract was made with ink.

Further, in the structure in which the light scattering layer uses the same ink as the light scattering portion, the light scattering layer forming surface of the protruding portion and the light scattering portion forming surface of the light guide plate are flush with each other.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The edge light type surface emitting device according to the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a partially enlarged rear view showing an embodiment of a projecting portion of a light guide plate of an edge light type surface emitting device according to the present invention, and FIG. 2 is a projecting portion of the edge light type surface emitting device of FIG. 4 is a partial enlarged rear view showing an embodiment of the protruding portion of the light guide plate of the edge light type surface emitting device according to the present invention.
3A and 3B are views for explaining the optical action of the light amount adjusting unit of the protruding portion in the edge light type surface emitting device of FIG. 3, FIG. 5 is a sectional view taken along the line AA of FIG. 4 for explaining the optical action of the light amount adjusting unit, and FIG. FIG. 10 is an exploded view showing an example of a general protruding portion in a light guide plate of a light type surface light emitting device, FIG. 10 is an exploded view showing another example of a protruding portion in a light guide plate of an edge light type surface light emitting device, and FIG. FIG. 13 is an exploded view showing an example of another projecting portion of the light guide plate of the edge light type surface light emitting device. FIG. 13 shows a case where the light amount adjusting portion of the projecting portion of the edge light type surface light emitting device of FIG. FIG. 14 is a diagram for explaining the optical action, and FIG.
FIG. 6 is a view for explaining an optical action when the light amount adjusting portion of the protruding portion in the edge light type surface emitting device is composed of a light absorbing layer,
FIG. 15 is an AA of FIG. 14 for explaining the optical action of the light quantity adjusting unit.
It is a line sectional view. In the figure, 1 is a light guide plate, 2 is a linear light source, 3 is a protruding portion, 4 is a chassis, 5 is a recessed portion, 6 is a light scattering portion, 7
Is a display area, 8 is a light quantity adjusting unit, and 9 is light.

In the edge light type surface light emitting device according to the present invention, the linear light source 2 is arranged on at least one of two opposing side surfaces of the light guide plate 1 made of a transparent resin plate. The transparent resin plate used for the light guide plate 1 is not particularly limited as long as it is a substance that allows light to pass efficiently, and for example, acrylic, polycarbonate, polystyrene, acrylic styrene, polyvinyl chloride, etc. are used. In addition, the cross-sectional shape of the light guide plate 1 may be such that an inclined surface portion is formed on the back surface such that the inclined surface portion becomes thinner as the distance from the linear light source 2 increases.
It may be flat. Further, the light guide plate 1 may be curved. Regarding the thickness of the light guide plate 1, the thickest part is 1.8 to 4.5.
A material having a size of about mm can be used. As the line light source 2, a cathode ray tube such as a hot cathode ray tube or a cold cathode ray tube having a diameter of 1.8 to 3.0 mm, a light emitting diode or the like may be used.
When the light emitting diode is used as the linear light source 2, a plurality of light emitting diodes are arranged in a line and used, or when the light emitting diode is arranged on the end face of the rod-shaped light guide to cause the rod-shaped light guide to emit light, the line referred to in the present invention. It corresponds to the light source.

A display area 7 of the liquid crystal panel is provided on the back surface of the light guide plate 1.
Corresponding to, the light scattering section 6 scatters and reflects the light guided from the linear light source 2 into the light guide plate 1, and directs a part of the light toward the front surface side of the light guide plate 1. Further, the light scattering section 6 adjusts the amount of light traveling toward the surface of the light guide plate 1 by changing the area ratio thereof. In order to change the area ratio of the light-scattering portion 6, the light-scattering portion 6 is composed of dots having an arbitrary shape,
This is done by changing the dot size or the number of dots depending on the position. The shape of the dot is not particularly limited, and may be any shape such as round dot, square dot, chain dot. Alternatively, it may be formed in a stripe shape. As a method of forming the light scattering portion 6, for example, a printing method such as gravure printing using a matte ink, offset printing, screen printing, or the like, or a transfer method, or a known technique can be used. When the matte ink is used, the light scattering property can be further improved by using an ink containing a particulate transparent substance such as calcium carbonate or silica having a refractive index substantially equal to or lower than that of the light guide plate 1.

The basic change of the area ratio is changed so that the area ratio becomes larger at a position distant from the linear light source 2 than at the vicinity of the linear light source 2. In the portion where the area ratio of the light scattering portion 6 is small, most of the light emitted from the linear light source 2 repeats total reflection inside the light guide plate 1 where the incident angle and the reflection angle are the same, and the back portion of the light guide plate 1 is repeated. Are sequentially led to. The rest of the light emitted from the linear light source 2 is scattered by the light scattering portion 6 and directly guided to the surface of the light guide plate 1, or passes through the light scattering portion 6 once and reaches the chassis 4. The light is reflected by the chassis 4, enters the light scattering portion 6 again, and is then indirectly guided to the surface of the light guide plate 1. Further, a part of the light scattered by the light scattering section 6 is transferred to total reflection inside the light guide plate 1. On the other hand, in the part where the area ratio of the light scattering portion 6 is large, total reflection is less likely to occur than in the part where the area ratio is small. Therefore, it is difficult to directly emit the light from the linear light source 2, and if the area ratio of the portion distant from the linear light source 2 is increased, the amount of the light emitted from the surface of the light guide plate 1 is balanced as a whole. It will be easier. In the case where the line light source 2 is arranged on only one side surface, when the side surface opposite to the side surface on which the line light source 2 is arranged has strong reflection and abnormally high brightness is shown near the opposite side surface, the line light source 2 is arranged. The area ratio in the vicinity of the side surface opposed to the above-described side surface is equal to or higher than that until then, and the increase rate is smaller than the increase rate up to that point.

Further, two side surfaces of the light guide plate 1 which are perpendicular to the side surface on which the linear light source 2 is arranged have projecting portions 3 by projecting a part of the resin plate. The feature of the present invention is that these projecting portions are provided. In order to prevent the generation of bright spots and bright lines due to 3 in the above, a light amount adjusting unit 8 for suppressing the amount of light traveling toward the wall surface of the protrusion 3 is provided on the back surface of the protrusion 3.

The protrusion 3 is for fixing the light guide plate 1 to the chassis 4 so that the light guide plate 1 does not fall off due to an impact such as a drop, and the chassis 4 has a recess 5 that fits into the protrusion 3.
Is provided. In order for the protrusion 3 to exert its fixing function, only one of the two side faces of the light guide plate 1 that are perpendicular to the side face on which the linear light source 2 is arranged is insufficient, and the protrusion 3 is formed on both side faces. Required. Further, a plurality of protrusions 3 may be provided on each side surface. In addition, the linear light source 2 of the protruding portion 3
It is more preferable not to align the positions from the above, the size of the protruding portion 3, and the like, because the back and front of the light guide plate 1 will not be accommodated in the chassis 4 by mistake.

As for the shape of the protruding portion 3, for example, the planar shape is a strip shape (see FIGS. 3, 4, 7, and 12), and the linear light source 2 of the two parallel wall surfaces in the case of a strip shape. The wall surface on the side far away from the wall surface is eliminated or the area is kept small, that is, the plane shape is a quarter ellipse (Fig. 1,
2 and 10), a shape such as a triangle or a trapezoid, or a shape of a strip having a chamfered corner on the side far from the line light source 2, but the light guide plate 1 can be firmly fixed to the chassis 4. In addition, any shape can be used as long as it is not difficult to manufacture with a mold or the like. From the viewpoint of fixation, it is preferable that the protrusion 3 has at least one wall surface parallel to the linear light source 2. The degree of protrusion of the protrusion 3 is 0.5 to
It is about 6 mm. If it exceeds 6 mm, it is difficult to narrow the frame of the liquid crystal panel, and if it is less than 0.5 mm, the light guide plate may fall off due to an impact such as dropping.

A light quantity adjusting portion 8 provided on the back surface of the protruding portion 3
There is a light scattering layer. The light amount adjusting unit 8 formed of a light scattering layer scatters the light 9 from the linear light source 2 that is incident on the light guide plate 1 and is guided to the protrusion 3 while repeating total reflection before reaching the wall surface of the protrusion 3. (See Figures 2, 4 and 5)
Therefore, even when the shape of the protrusion 3 is a strip, it is possible to suppress the light emitted from the wall surface of the protrusion 3 to the outside of the light guide plate 1. As a result, even if the light emitted from the wall surface of the protrusion 3 is scattered and reflected mainly on the side of the linear light source 2 on the wall surface of the recess 5 of the chassis 4, the light travels toward the display area 7 on the surface side of the light guide plate 1. The amount becomes small, and the protruding portion 3 of the display area 7
Abnormally bright spots do not occur in the vicinity. A part of the light scattered by the light amount adjusting unit 8 formed of the light scattering layer also goes to the surface side of the light guide plate 1 but is small, and the scattered light 9 mainly travels in a direction away from the linear light source 2 and the light guide plate 1. So
Does not adversely affect surface emission.

Further, the light quantity adjusting section 8 comprising a light scattering layer is
The light 9 from the linear light source 2 that is incident on the light guide plate 1 and is guided to the protrusion 3 while repeating total reflection is scattered before reaching the wall surface of the protrusion 3 (see FIGS. 2, 4, and 5). Therefore, even when the shape of the protruding portion 3 is a quarter ellipse, a triangle, a trapezoid, or the like, it is possible to suppress the light that is totally reflected by the wall surface of the protruding portion 3 and heads toward the gradation pattern. As a result, the total reflection light from the protrusion 3 does not cause unnecessary scattered reflection in the gradation pattern, and the bright line does not occur in the display area 7. A part of the light scattered by the light amount adjusting unit 8 made of the light scattering layer also goes to the gradation pattern, but it is slight, and the scattered light 9 mainly travels in a direction away from the linear light source 2 and the light guide plate 1. Does not adversely affect

As a method of forming the light quantity adjusting portion 8 composed of the light scattering layer, for example, a printing method such as gravure printing, offset printing, screen printing using a matte ink, or a transfer method can be used. When the matte ink is used, the light scattering property can be further improved by using an ink containing a particulate transparent substance such as calcium carbonate or silica having a refractive index substantially equal to or lower than that of the light guide plate 1. The light amount adjusting unit 8 has an area ratio of 100%.
It may be formed by (solid) or may be formed by a dot gradation pattern similarly to 6 as in the light scattering portion.

The light-scattering layer provided on the back surface of the protrusion 3 is the same as that of the light-scattering portion 6 provided corresponding to the display area 7 of the liquid crystal panel when the ink has the same composition. It can be provided together with the light scattering portion using a printing plate or a transfer material, which is preferable in terms of process reduction and cost reduction. Further, in this case, when the light guide plate 1 is molded so that the light-scattering layer forming surface of the protruding portion 3 and the light-scattering portion 6 forming surface of the light guide plate 1 are flush with each other, the light amount formed by the light-scattering layer under the same conditions. The adjusting portion 8 and the light scattering portion 6 can be formed, which is preferable in terms of preventing printing defects such as blurring and durability of the plate.

Further, the light quantity adjusting portion 8 provided on the back surface of the protrusion 3 may be a light absorbing layer. In this case, the light amount adjusting unit 8 including the light absorbing layer receives the light 9 from the linear light source 2 that is incident on the light guide plate 1 and is guided to the protrusion 3 while repeating total reflection before reaching the wall surface of the protrusion 3. (See FIGS. 13, 14, and 15), the light emitted from the wall surface of the protruding portion 3 to the outside of the light guide plate 1 can be suppressed or projected like the light amount adjusting portion 8 including the light scattering layer. It is possible to suppress the light that is totally reflected by the wall surface of the portion 3 and goes to the gradation pattern. Therefore, according to the light amount adjusting unit 8 including the light absorbing layer, bright spots or bright lines due to the protrusion 3 on the side surface of the light guide plate 1 are not generated, as in the light amount adjusting unit 8 including the light scattering layer described above.

As a method of forming the light quantity adjusting portion 8 composed of a light absorbing layer, for example, a printing method such as gravure printing using black or gray ink, offset printing, screen printing, or a transfer method can be used.

Further, in the edge light type surface emitting device of the present invention, a back surface reflection layer may be arranged on the back surface of the light guide plate 1. The back surface reflection layer reflects the light that has not been returned to the inside of the light guide plate 1 by being scattered and transmitted downward in the light scattering portion to the light guide plate 1 side so that the light can be efficiently used. When the chassis 4 is of a frame type and the surface opposite to the back surface of the light guide plate 1 is open, light cannot be returned to the light guide plate 1 by the chassis 4, so it is necessary to arrange this back surface reflection layer. preferable. As the material of the back reflection layer, for example, a film or plate in which a white pigment is mixed in a resin, an aluminum plate on which white coating or white printing is performed, or the like can be used.

When the linear light source 2 is arranged on only one side surface of the light guide plate 1, a side reflection layer may be arranged on the side surface opposite to the side surface on which the linear light source 2 is arranged. The side surface reflection layer reflects the light that has emerged from the side surface of the light guide plate 1 and cannot be returned to the light guide plate 1 side so that the light can be used efficiently.
As the material of the side surface reflection layer, the same material as the back surface reflection layer may be used. Alternatively, a white reflective layer may be formed on the side surface of the light guide plate 1 by a hot stamp method to form a side reflective layer.

A light diffusing layer may be arranged on the surface of the light guide plate 1. The light diffusion layer is for diffusing light emitted from the surface of the light guide plate 1 and smoothing the luminance distribution. The following materials are preferable as the material of the light diffusion layer. (1) A film or plate coated with a light diffusing substance. (2) A film or plate having a light diffusing property by itself. (3) A milky white resin film or plate. Also, a plurality of light diffusion layers may be formed.

[0028]

[Example] <Example 1> Vertical 288 mm, horizontal 218 m
m, maximum lateral thickness 2.5 mm, minimum lateral thickness 0.7
A transparent acrylic resin plate having a wedge-shaped cross section of mm is used as a light guide plate, and a pipe length 29 is provided on the side surface having the maximum thickness of the light guide plate.
A cold cathode ray tube having a diameter of 0 mm and a diameter of 2 mm is arranged as a line light source, and a side surface reflection layer is provided by performing transfer using a hot stamp foil having a transfer layer in which titanium oxide is contained in a polyester resin on the other side surface facing each other. A large number of dots are screen-printed on the back surface of the light plate using a matte ink containing silica in acrylic resin to make a length of 286 mm and a width of 215 m.
A light-scattering portion having a gradation pattern of m was provided. Incidentally, the area ratio of the light scattering portion, in the direction perpendicular to the axial direction of the linear light source, becomes gradually smaller as the distance from the linear light source side end portion of the light scattering portion decreases in the vicinity of the side reflection layer side end portion of the light scattering portion. I made it constant. In addition, a white polyethylene terephthalate film (Toray E60
L) was arranged as a back reflection layer, and a resin film (D121 manufactured by Tsujiden Co., Ltd.) coated with a light diffusion substance was arranged as a light diffusion plate on the surface of the light guide plate.

A part of the resin plate is projected on one of the two side surfaces of the light guide plate, which are perpendicular to the side surface on which the linear light source is arranged, and is a quarter.
Each of the elliptical protrusions was provided. The protrusions on these side surfaces are provided by protruding by 1.5 mm from the side surface on which the linear light source is arranged so as to be stepwise different in the range of 70 to 75 mm and in the range of 47.5 to 52.5 mm.
Then, the same ink as the matte ink used for the light scattering portion is used on the back surface of the protruding portion, and the area ratio is 100% (solid).
The light amount adjusting part of No. 2 was screen-printed with a clearance of 0.3 mm from the wall surface of the protrusion. The light scattering portion and the light amount adjusting portion were provided by printing once using the same plate. Further, the light-scattering layer forming surface of the protruding portion and the light-scattering portion forming surface of the light guide plate are flush with each other.

In the edge light type surface emitting device configured as described above, before the light from the linear light source which is incident on the light guide plate and is guided to the projecting portion while repeating the total reflection reaches the wall surface of the projecting portion. Since the light amount adjusting section composed of the light scattering layer scatters, it is possible to suppress the light that is totally reflected by the wall surface of the protruding section and goes to the light scattering section composed of the gradation pattern, and no bright line is generated in the display region.

<Embodiment 2> Height 321 mm, width 241
mm, 5.0 mm thick transparent acrylic resin plate with a flat cross section is used as a light guide plate, and cold cathode ray tubes having a tube length of 320 mm and a diameter of 2 mm are arranged as linear light sources on two side surfaces in the longitudinal direction of the light guide plate. A large number of dots were screen-printed on the back surface of the sheet using a matte ink containing silica in an acrylic resin to provide a light-scattering portion having a gradation pattern of 304 mm in length and 228 mm in width. The area ratio of the light-scattering portion was gradually decreased in the direction perpendicular to the axial direction of the linear light source as the distance from the linear light source was increased, and was minimized in the central portion. In addition, a white polyethylene terephthalate film (E60L made by Toray Co., Ltd.) is arranged on the back surface of the light guide plate as a back reflection layer, and a resin film coated with a light diffusing substance (D12 made by Tsujiden Co., Ltd.) is provided on the surface of the light guide plate.
1) was placed as a light diffusion plate.

On the two side surfaces of the light guide plate, which are at right angles to the side surfaces on which the linear light sources are arranged, part of the resin plate is made to protrude, and strip-shaped protruding portions are provided one by one. The protrusions on these side surfaces are provided so as to protrude by 3 mm from the side surface on which one of the line light sources is arranged so as to make a step difference in the range of 113 to 127 mm and 89 to 126 mm. Then, the same ink as the matte ink used for the light-scattering portion is used on the back surface of the protruding portion, and a light amount adjusting portion having an area ratio of 100% (solid) is provided with a clearance of 0.3 mm from the wall surface of the protruding portion to perform screen printing. did. The light scattering portion and the light amount adjusting portion were provided by printing once using the same plate. Further, the light-scattering layer forming surface of the protruding portion and the light-scattering portion forming surface of the light guide plate are flush with each other.

In the edge light type surface emitting device configured as described above, before the light from the linear light source, which is incident on the light guide plate and is guided to the protrusion while repeating total reflection, reaches the wall surface of the protrusion. Since the light quantity adjusting section made of the light scattering layer scatters the light, it is possible to suppress the light emitted from the wall surface of the protruding portion to the outside of the light guide plate, and the bright spot based on the scattering reflection on the chassis wall surface does not occur in the display area.

<Example 3> The same as Example 1 except that a black ink was used as the ink used for the light amount adjusting section and a light amount adjusting section consisting of a light absorbing layer was provided by screen printing different from the light scattering section. did. The edge-light type surface emitting device configured as described above is configured so that the light from the linear light source, which is incident on the light guide plate and is repeatedly reflected to the protrusion and is guided to the protrusion, is emitted from the light absorption layer before reaching the wall surface of the protrusion. Is absorbed by the light amount adjusting section, it is possible to suppress the light that is totally reflected by the wall surface of the protruding section and goes to the light scattering section formed of the gradation pattern.
No bright line was generated in the display area.

<Example 4> The same as Example 2 except that a black ink was used as the ink used for the light amount adjusting section and a light amount adjusting section consisting of a light absorbing layer was provided by screen printing different from the light scattering section. did. The edge-light type surface emitting device configured as described above is configured so that the light from the linear light source, which is incident on the light guide plate and is repeatedly reflected to the protrusion and is guided to the protrusion, is emitted from the light absorption layer before reaching the wall surface of the protrusion. Since the light amount adjusting unit absorbs the light, the light emitted from the wall surface of the protruding portion to the outside of the light guide plate can be suppressed, and a bright spot due to the scattering reflection on the chassis wall surface does not occur in the display area.

[0036]

Since the edge light type surface emitting device according to the present invention has the above-described structure and operation, it has the following effects.

That is, a line light source is arranged on at least one of two opposite side surfaces of a light guide plate made of a clear resin plate, and a light scattering portion is provided on the back surface of the light guide plate in the vicinity of the line light source corresponding to the display area of the liquid crystal panel. Is also provided with a gradation pattern such that the area ratio increases at a location away from the linear light source,
In addition, in the edge light type surface light emitting device in which two side surfaces that are perpendicular to the side surface on which the linear light source of the light guide plate is arranged have a protruding portion by protruding a part of the resin plate, in the rear surface of the protruding portion to the wall surface of the protruding portion. Since the light amount adjustment unit that suppresses the amount of light going is provided, the light amount adjustment unit scatters or absorbs before the light from the linear light source guided to the protrusion while repeating total reflection reaches the wall surface of the protrusion, No bright spots or bright lines are generated due to the protrusions on the side surface of the light guide plate.

[Brief description of drawings]

FIG. 1 is a partially enlarged rear view showing an embodiment of a protruding portion in a light guide plate of an edge light type surface light emitting device according to the present invention.

FIG. 2 is a diagram illustrating an optical action when the light amount adjusting unit of the protruding portion in the edge light type surface emitting device of FIG. 1 is formed of a light scattering layer.

FIG. 3 is a partially enlarged rear view showing an embodiment of a protruding portion of the light guide plate of the edge light type surface emitting device according to the present invention.

FIG. 4 is a diagram illustrating an optical action when the light amount adjusting unit of the protruding portion in the edge light type surface light emitting device of FIG. 3 includes a light scattering layer.

5 is a cross-sectional view taken along the line AA in FIG. 4 for explaining the optical action of the light quantity adjusting unit.

FIG. 6 is a schematic diagram illustrating a problem of a light guide plate having no protruding portion.

FIG. 7 is an exploded view showing an example of a general protrusion in a light guide plate of an edge light type surface light emitting device.

8A and 8B are views for explaining the optical action of the wall surface of the protruding portion in the edge light type surface light emitting device of FIG.

FIG. 9 is an AA of FIG. 7 for explaining the optical action of the wall surface of the protruding portion.
It is a line sectional view.

FIG. 10 is an exploded view showing an example of another projecting portion of the light guide plate of the edge light type surface emitting device.

FIG. 11 is a diagram illustrating an optical action of a wall surface of a protruding portion in the edge light type surface light emitting device of FIG.

FIG. 12 is an exploded view showing an example of another projecting portion of the light guide plate of the edge light type surface emitting device.

FIG. 13 is a diagram illustrating an optical action when the light amount adjusting unit of the protruding portion in the edge light type surface light emitting device of FIG. 1 is formed of a light absorbing layer.

FIG. 14 is a diagram illustrating an optical action when the light amount adjusting unit of the protruding portion in the edge light type surface light emitting device of FIG. 3 is formed of a light absorbing layer.

FIG. 15A in FIG. 14 for explaining the optical action of the light quantity adjusting unit.
It is an A line sectional view.

[Explanation of symbols]

1 Light guide plate 2 line light source 3 protrusion 4 chassis 5 hollow 6 Light scattering part 7 display area 8 Light intensity adjustment unit 9 light

Claims (5)

[Claims] 1. A line light source is disposed on at least one of two opposing side surfaces of a light guide plate made of a transparent resin plate, and a light scattering portion is provided on the back surface of the light guide plate in the vicinity of the line light source corresponding to the display area of the liquid crystal panel. Is also provided in a gradation pattern such that the area ratio increases at a position distant from the linear light source, and the two side surfaces of the light guide plate that are perpendicular to the side surface on which the linear light source is arranged project a part of the resin plate to form a protruding portion. An edge light type surface light emitting device having an edge light type surface light emitting device having a light amount adjusting section for suppressing an amount of light traveling toward a wall surface of the protruding portion. 2. The edge light type surface light emitting device according to claim 1, wherein the light amount adjusting portion provided on the back surface of the protruding portion is a light scattering layer. 3. The light-scattering layer provided on the back surface of the protruding portion is provided by using the same ink as that of the light-scattering portion provided corresponding to the display area of the liquid crystal panel. The edge light type surface emitting device described. 4. The edge light type surface emitting device according to claim 3, wherein the light-scattering layer forming surface of the protruding portion and the light-scattering portion forming surface of the light guide plate are flush with each other. 5. The edge light type surface light emitting device according to claim 1, wherein the light amount adjusting portion provided on the back surface of the protruding portion is a light absorbing layer.