WO2013042602A1

WO2013042602A1 - Lighting device and display device provided with same

Info

Publication number: WO2013042602A1
Application number: PCT/JP2012/073404
Authority: WO
Inventors: 健太郎鎌田
Original assignee: シャープ株式会社
Priority date: 2011-09-20
Filing date: 2012-09-13
Publication date: 2013-03-28

Abstract

Provided is a lighting device that can improve uniformity of brightness at the edges of a screen. This lighting device (10) is provided, on a light guide plate (12), with a plurality of scattering dots (12e) that scatter light and make the light exit from a light exit surface (12a). The plurality of scattering dots include, on the edge part of the light guide plate, scattering dots (12h) provided on the light source (11) facing surface and scattering dots (12g) provided between light sources and having an external form larger than the scattering dots (12h). The disposition pitch (P1) of the light sources is equal to an integer multiple of 2 or more than the disposition pitch (P2) of the scattering dots (12e).

Description

LIGHTING DEVICE AND DISPLAY DEVICE HAVING THE SAME

The present invention relates to a lighting device and a display device including the same, and more particularly to a lighting device including a light guide plate on which light from a light source is incident and a display device including the same.

A liquid crystal display device (display device) on which a non-luminous display panel (illuminated member) is mounted is usually also equipped with a backlight device (illumination device) that emits light to the display panel. As such a backlight device, a backlight device including a plurality of LEDs (light sources) and a light guide plate on which light from the LEDs is incident is known.

10 and 11 are diagrams showing an example of the structure of a conventional display device including an LED and a light guide plate. As shown in FIG. 10, the display device 1001 includes a display panel (illuminated member) 1002 and a backlight device (illumination device) 1010 that illuminates the display panel 1002. The backlight device 1010 includes a plurality of LEDs (light sources) 1011, a light guide plate 1012 on which light from the LEDs 1011 is incident, a plurality of optical sheets 1013 disposed on the light emitting surface 1012 a side of the light guide plate 1012, and a light guide plate 1012 includes a reflection sheet 1014 disposed on the back surface 1012b side of 1012 and a chassis 1015 for housing these.

The light guide plate 1012 is the widest surface and has a light emitting surface 1012a provided on the display panel 1002 side, a back surface 1012b provided on the opposite side of the light emitting surface 1012a, and an LED 1011 facing each other and the A direction. And a side surface 1012d extending in a direction intersecting the light incident side surface 1012c (direction B).

As shown in FIG. 11, the light exit surface 1012a of the light guide plate 1012 has a plurality of light that scatters the light incident on the light incident side surface 1012c, changes the traveling direction, and emits light from the light exit surface 1012a to the display panel 1002 side. The scattering dot (scattering part) 1012e is formed.

Here, normally, the amount of light emitted from the light guide plate decreases as the distance from the LED (light source) increases. For this reason, in the display device 1001, the plurality of scattering dots 1012e are formed so that the outer shape (diameter) increases as the distance from the LED 1011 increases. Thereby, it is possible to suppress a decrease in luminance at the center of the screen.

Note that a display device including a light guide plate having the above-described structure is disclosed in Patent Document 1, for example.

JP 2002-208307 A

However, in the conventional display device 1001, the amount of light emitted from the portion S1001 between the adjacent LEDs 1011 at the edge portion of the light guide plate 1012 is smaller than the amount of light emitted from the front portion S1002 of the LED 1011. For this reason, since the part S1001 becomes dark on the screen, there is a problem that it is difficult to improve the uniformity of the luminance at the peripheral edge of the screen.

The problem that the portion S1001 becomes dark on the screen is likely to occur when the LEDs 1011 are arranged close to the light guide plate 1012 or the arrangement pitch of the LEDs 1011 is increased. Further, the dark portion S1001 becomes wider as approaching the outside of the light guide plate 1012 (on the light incident side surface 1012c side), for example, as indicated by a two-dot chain line in FIG.

The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a lighting device capable of improving the uniformity of luminance at the peripheral edge of the screen and a display device including the same. Is to provide.

In order to achieve the above object, an illumination device according to the present invention includes a plurality of light sources arranged in a predetermined direction, a light incident side surface on which light from the light sources is incident, and light emission for emitting light toward an illuminated member. And a light guide plate including a back surface disposed on the side opposite to the light output surface, and the light output surface or back surface of the light guide plate scatters light incident on the light incident side surface to scatter the light output surface. A plurality of scattering portions to be emitted from the light source are provided, and the plurality of scattering portions are arranged at a uniform pitch in a predetermined direction, and the plurality of scattering portions are first provided at the edge of the light guide plate and in front of the light source. A scattering portion and a second scattering portion provided between adjacent light sources and having an outer shape larger than that of the first scattering portion, and the arrangement pitch of the light sources in a predetermined direction is 2 of the arrangement pitch of the scattering portions in the predetermined direction. Equal to an integer multiple of

In addition, the front of the light source means the light emission direction of the light source.

In this illuminating device, as described above, the plurality of scattering portions are provided at the edge of the light guide plate between the first scattering portion provided in front of the light source and between the adjacent light sources, than the first scattering portion. And a second scattering portion having a large outer shape. Thereby, in the edge part of a light-guide plate, it can suppress that the quantity of the light radiate | emitted from the part between adjacent light sources becomes smaller than the quantity of the light radiate | emitted from the front part of a light source. For this reason, it can suppress that the part between adjacent light sources becomes dark on a screen. That is, it is possible to improve the uniformity of luminance at the periphery of the screen.

Also, as described above, the arrangement pitch of the light sources is equal to an integer multiple of 2 or more of the arrangement pitch of the scattering portions. Thereby, in each light source, since the positional relationship of a light source and a scattering part can be made the same, the uniformity of the brightness | luminance in a screen peripheral part can be improved more.

In the above illumination device, preferably, the scattering portion may be formed in a dot shape.

In the illumination device in which the scattering portion is formed in a dot shape, preferably, the plurality of scattering portions form a plurality of dot rows arranged at a predetermined arrangement pitch in a predetermined direction, and 1 from the light incident side surface side. The number of the second scattering portions of the dot row arranged in the row is larger than the number of the second scattering portions of the dot row arranged in the second row from the light incident side surface side. If comprised in this way, in the edge part of a light-guide plate, the area in which a 2nd scattering part is formed will become large as it approaches a light-incidence side surface. Since the dark part of the edge of the light guide plate that has occurred in the conventional structure becomes wider as it approaches the light incident side surface of the light guide plate, the brightness uniformity can be further improved if configured as described above. .

In the above illumination device, preferably, the scattering portion provided in the region farthest from the light source has a larger outer shape than the second scattering portion. If comprised in this way, since it can suppress that the quantity of the light radiate | emitted from the area | region furthest from a light source can be suppressed, the uniformity of the brightness | luminance of the whole screen can be improved.

In the above illuminating device, preferably, the scattering portion includes irregularities formed on the light emitting surface or the back surface of the light guide plate. If comprised in this way, a scattering part can be provided easily.

In addition, the unevenness is a concept including a structure having only concave portions and a structure having only convex portions.

In the above illumination device, preferably, the scattering portion includes a reflective layer provided on the back surface of the light guide plate. If comprised in this way, a scattering part can be provided easily.

The display device of the present invention includes the illumination device having the above-described configuration and a display panel illuminated by the illumination device. If comprised in this way, the display apparatus which can improve the uniformity of the brightness | luminance in a screen peripheral part can be obtained.

As described above, according to the present invention, it is possible to easily obtain an illuminating device capable of improving the uniformity of luminance at the peripheral edge of the screen and a display device including the same.

It is sectional drawing which showed the structure of the display apparatus of 1st Embodiment of this invention. It is the figure which showed the structure of the light-guide plate and light source of 1st Embodiment of this invention shown in FIG. It is sectional drawing which showed the structure of the scattering dot of the light-guide plate of 1st Embodiment of this invention shown in FIG. It is sectional drawing which showed the structure of the scattering dot of the light-guide plate of 1st Embodiment of this invention shown in FIG. It is sectional drawing which showed the structure of the scattering dot of the light-guide plate of 1st Embodiment of this invention shown in FIG. It is the enlarged view which showed the structure of the scattering dot and light source of the light-guide plate of 1st Embodiment of this invention shown in FIG. It is the figure which showed the structure of the light-guide plate and light source of 2nd Embodiment of this invention. It is the enlarged view which showed the structure of the scattering dot and light source of the light-guide plate of 3rd Embodiment of this invention. It is the enlarged view which showed the structure of the scattering dot and light source of the light-guide plate of 3rd Embodiment of this invention. It is sectional drawing which showed the structure of the conventional display apparatus. It is the top view which showed the structure of the light-guide plate and light source of the conventional display apparatus shown in FIG. FIG. 11 is an enlarged view for explaining a dark portion generated between adjacent light sources at the edge portion of the light guide plate of the conventional display device shown in FIG. 10.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In order to facilitate understanding, even a cross-sectional view may not be hatched.

(First embodiment)
The structure of the display device 1 according to the first embodiment of the present invention will be described with reference to FIGS.

The display device 1 according to the first embodiment of the present invention is used in, for example, a television receiver. As shown in FIG. 1, the display device 1 includes a display panel 2 (illuminated member) and a lighting device 10 that is disposed on the back side of the display panel 2 and illuminates the display panel 2. Note that the “back side (lower side in FIG. 1)” of the “back side of the display panel 2” is an orientation concept that is also applied to other components.

The display panel 2 is composed of a liquid crystal display panel, and has two glass substrates that sandwich a liquid crystal layer (not shown). The display panel 2 displays an image by being illuminated by the illumination device 10.

The lighting device 10 is an edge light type (also referred to as a side light type) backlight device. The lighting device 10 includes a plurality of light sources 11, a light guide plate 12 that guides light from the light sources 11, a plurality of optical sheets 13 that are disposed on the light emission surface 12 a side of the light guide plate 12, and the back surface of the light guide plate 12. The reflective sheet 14 arrange | positioned at the 12b side and the chassis 15 which accommodates these are included.

As shown in FIG. 2, the plurality of light sources 11 are disposed to face a light incident side surface 12 c described later of the light guide plate 12. In other words, the plurality of light sources 11 are arranged along two opposing sides of the light guide plate 12. The plurality of light sources 11 are arranged at predetermined intervals in the A direction (longitudinal direction of the light guide plate 12). The light source 11 is composed of an LED, for example, and emits white light. The direction A is an example of the “predetermined direction” in the present invention.

The arrangement pitch P1 in the A direction of the light source 11 is equal to two or more integer multiples (for example, six times) of the arrangement pitch P2 in the A direction of scattering dots 12e described later.

The light guide plate 12 is formed in a flat plate shape using a material having a refractive index greater than 1, as shown in FIGS. The light guide plate 12 is the widest surface and emits planar light toward the display panel 2, a back surface 12b provided on the opposite side of the light output surface 12a, and light from the light source 11. Is incident on the light incident side surface 12c (the long side of the light guide plate 12) and the side surface 12d (the light guide plate 12) extending in a direction orthogonal to (intersecting) the light incident side surface 12c (the B direction which is the short direction of the light guide plate 12). Short side). The light guide plate 12 has a function of guiding light incident on the light incident side surface 12 c and emitting planar light toward the display panel 2 by changing the traveling direction of the light.

For example, on the back surface 12b of the light guide plate 12, a plurality of (a plurality of) scattering dots 12e (scattering) that change the traveling direction of the light incident on the light incident side surface 12c and emit light from the light emitting surface 12a to the display panel 2 side. Part) is formed. In the drawing, in order to facilitate understanding, the number of scattering dots 12e is reduced and the scattering dots 12e are drawn larger.

The scattering dots 12e are concave portions or convex portions formed on the back surface 12b of the light guide plate 12, for example, as shown in FIGS. The scattering dots 12e may be concave portions or convex portions formed on the light emitting surface 12a of the light guide plate 12 although not shown. The concave portion or the convex portion may be formed in a hemispherical shape, for example, or may be formed in a quadrangular pyramid shape or other shapes. Further, instead of a dot shape such as a hemispherical shape or a quadrangular pyramid shape, for example, a prism-shaped scattering portion may be formed. Further, the scattering dots 12e may be a reflective layer provided on the back surface 12b of the light guide plate 12, as shown in FIG. The reflective layer may be formed of, for example, white ink or may be formed of other materials.

The plurality of scattering dots 12e are arranged in a plurality of rows extending along the A direction. Specifically, as shown in FIG. 6, the scattering dots 12e constitute a plurality of dot rows 12f arranged at a uniform pitch (arrangement pitch P2) in the A direction, and the plurality of dot rows 12f are predetermined in the B direction. Are arranged at a pitch of. The dot row 12f is arranged so as to be shifted by half the pitch in the A direction with respect to the adjacent dot row 12f. For this reason, the plurality of scattering dots 12e are arranged in a staggered manner.

At the edge of the light guide plate 12, the scattering dot 12 g (second scattering part) provided between the adjacent light sources 11 is larger than the scattering dot 12 h (first scattering part) provided in front of the light source 11. It has a diameter (outer shape). In addition, the number of scattering dots 12g arranged in the first row (outermost row) from the light incident side surface 12c side (for example, four between adjacent light sources 11) is the second row from the light incident side surface 12c side ( More than the number of scattering dots 12g arranged in the second row from the outside (for example, three between adjacent light sources 11).

Except for the scattering dot 12g, the scattering dot 12e is formed to have a larger diameter (outer shape) as it moves away from the light source 11 (toward the inside of the light guide plate 12). As shown in FIG. 2, the scattering dot 12e provided in the region S1 farthest from the light source 11 (the center portion of the light guide plate 12) has a larger diameter (outer shape) than the scattering dot 12g.

2 and 6, the scattering dots 12g are provided from the outside to the second row, but the scattering dots 12g may also be provided from the outside to the third row and thereafter.

As shown in FIG. 6, in each light source 11, the positional relationship between the light source 11 and the scattering dots 12e is the same. Further, the scattering dots 12e are arranged so as to be symmetric with respect to each light source 11 in the A direction.

As shown in FIG. 1, the plurality of optical sheets 13 are composed of a diffusion plate, a prism sheet, a lens sheet, and the like, and have a function of diffusing light from the light guide plate 12 and condensing it at a predetermined viewing angle. Note that the diffusion plate, the prism sheet, the lens sheet, and the like are provided as necessary and may be omitted.

The reflection sheet 14 has a function of reflecting the light emitted from the back surface 12 b of the light guide plate 12 and causing the light to enter the light guide plate 12 again.

In the present embodiment, as described above, the plurality of scattering dots 12e are arranged between the scattering dots 12h provided in front of the light source 11 and the adjacent light sources 11 at the edge of the light guide plate 12. And 12 g of scattering dots having a larger diameter (outer shape). Thereby, it can suppress that the quantity of the light radiate | emitted from the part between adjacent light sources 11 in the edge part of the light-guide plate 12 becomes smaller than the quantity of the light radiate | emitted from the front part of the light source 11. For this reason, it can suppress that the part between adjacent light sources 11 becomes dark on a screen. That is, it is possible to improve the uniformity of luminance at the periphery of the screen.

As described above, the arrangement pitch P1 of the light source 11 in the A direction is equal to an integer multiple of 2 or more of the arrangement pitch P2 of the scattering dots 12e in the A direction. Thereby, in each light source 11, since the positional relationship of the light source 11 and the scattering dot 12e can be made the same, the uniformity of the brightness | luminance in a screen peripheral part can be improved more.

As described above, the plurality of scattering dots 12e form a plurality of dot rows 12f arranged at a predetermined arrangement pitch P2 in the A direction, and are arranged in the first row from the light incident side surface 12c side. The number of scattering dots 12g in the row 12f (for example, four between adjacent light sources 11) is the number of scattering dots 12g in the dot row 12f arranged in the second row from the light incident side surface 12c side (adjacent light sources 11). More than 3) between each other. Thereby, in the edge part of the light-guide plate 12, the area in which the scattering dot 12g is formed becomes large as it approaches the light-incidence side surface 12c. Since the dark part of the edge of the light guide plate that has occurred in the conventional structure becomes wider as it approaches the light incident side surface of the light guide plate, the brightness uniformity can be further improved if configured as described above. .

As described above, the scattering dot 12e provided in the region S1 farthest from the light source 11 has a larger diameter (outer shape) than the scattering dot 12g. Thereby, since it can suppress that the quantity of the light radiate | emitted from area | region S1 furthest from the light source 11 can be suppressed, the uniformity of the brightness | luminance of the whole screen can be improved.

(Second Embodiment)
In the display device according to the second embodiment of the present invention, as shown in FIG. 7, the plurality of light sources 11 are arranged along only one side (one long side) of the light guide plate 12.

The scattering

dots

12g and 12h are provided on one long side of the light guide plate 12 (on the light incident side surface 12c side), but are not provided on the other long side of the light guide plate 12.

Except for the scattering dot 12g, the scattering dot 12e is formed to have a larger outer shape as it moves away from the light source 11 (toward the lower side of the light guide plate 12 in FIG. 7). The scattering dot 12e provided in the region (the lower part in FIG. 7) S11 farthest from the light source 11 has a larger outer shape than the scattering dot 12g.

Other structures and effects of the second embodiment are the same as those of the first embodiment.

(Third embodiment)
In the display device according to the third embodiment of the present invention, as shown in FIG. 8, unlike the first and second embodiments, the scattering dots 12e are arranged in a matrix. That is, the dot row 12f is arranged so as not to be displaced in the A direction with respect to the adjacent dot row 12f.

The number of scattering dots 12g arranged in the first row from the light incident side surface 12c side (for example, four between adjacent light sources 11) is the scattering dot arranged in the second row from the light incident side surface 12c side. More than 12g (for example, two between adjacent light sources 11). As shown in FIG. 9, the number of scattering dots 12g arranged in the first row from the light incident side surface 12c and the number of scattering dots 12g arranged in the second row from the light incident side surface 12c are the same. It may be.

Other structures and effects of the third embodiment are the same as those of the first and second embodiments.

In addition, it should be thought that embodiment disclosed this time is an illustration and restrictive at no points. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims, and further includes meanings equivalent to the scope of claims and all modifications within the scope.

For example, in the above-described embodiment, an example in which the display panel is applied to a liquid crystal display panel has been described. However, the present invention is not limited thereto, and may be applied to a display panel other than the liquid crystal display panel.

Moreover, in the said embodiment, although the backlight apparatus which illuminates a display panel was demonstrated as an example of an illuminating device, this invention is applicable not only to this but the illuminating device which illuminates to-be-illuminated members other than a display panel. is there.

In the above embodiment, an example in which a plurality of light sources are arranged along two sides or one side of the light guide plate is shown. However, the present invention is not limited to this, and the plurality of light sources are arranged along the four sides of the light guide plate. It may be arranged.

In the above embodiment, the number of scattering dots 12g arranged in the first row from the light incident side surface side is greater than or equal to the number of scattering dots 12g arranged in the second row from the light incident side surface side. Although an example has been shown, the present invention is not limited to this. The number of scattering dots 12g arranged in the first row from the light incident side surface may be smaller than the number of scattering dots 12g arranged in the second row from the light incident side surface.

Further, a configuration obtained by appropriately combining the configurations of the above-described embodiments and modifications is also included in the technical scope of the present invention.

1 Display device 2 Display panel (illuminated member)
DESCRIPTION OF SYMBOLS 10 Illuminating device 11 Light source 12 Light guide plate 12a Light emission surface 12b Back surface 12c Light incident side surface 12e Scattering dot (scattering part)
12f dot row 12g scattering dot (second scattering part)
12h Scattering dots (first scattering part)
P1 arrangement pitch P2 arrangement pitch (pitch)
S1, S11 Distant area

Claims

A plurality of light sources arranged in a predetermined direction;
A light guide plate including a light incident side on which light from the light source is incident, a light emitting surface that emits light toward the illuminated member, and a back surface disposed on the opposite side of the light emitting surface;
With
The light exit surface or the back surface of the light guide plate is provided with a plurality of scattering portions that scatter light incident on the light incident side surface and emit the light from the light exit surface,
The plurality of scattering portions are arranged at a uniform pitch in the predetermined direction,
The plurality of scattering portions have outer shapes larger than the first scattering portions provided between the first scattering portions provided in front of the light source and the adjacent light sources at the edge of the light guide plate. 2 scattering parts,
The arrangement pitch of the light sources in the predetermined direction is equal to an integer multiple of 2 or more of the arrangement pitch of the scattering portions in the predetermined direction.
The lighting device according to claim 1, wherein the scattering portion is formed in a dot shape.
The plurality of scattering portions form a plurality of dot rows arranged at a predetermined arrangement pitch in the predetermined direction,
The number of second scattering portions of the dot row arranged in the first row from the light incident side surface side is larger than the number of second scattering portions of the dot row arranged in the second row from the light incident side surface side. The illuminating device according to claim 2, wherein there are many.
The illumination device according to any one of claims 1 to 3, wherein the scattering portion provided in a region farthest from the light source has a larger outer shape than the second scattering portion.
The lighting device according to any one of claims 1 to 4, wherein the scattering portion includes irregularities formed on the light emitting surface or the back surface of the light guide plate.
The lighting device according to any one of claims 1 to 4, wherein the scattering portion includes a reflective layer provided on the back surface of the light guide plate.
The lighting device according to any one of claims 1 to 6,
A display device comprising a display panel illuminated by the illumination device.