JP2007073399A - Lighting system and electro-optical device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lighting system and an electro-optical device capable of arranging many light-emitting elements on a light guide plate. <P>SOLUTION: The lighting system 3 includes a light guide plate 5 and a plurality of light-emitting diodes 6. A plurality of concavo-convex parts are formed on a side surface part used as an optical incident surface on the light guide plate 5. The plurality of light-emitting diodes 6 are provided at a plurality of unevenness parts in the plurality of the unevenness parts so as each light-irradiating face to be faced with the other. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an illumination device and an electro-optical device, and more particularly to an illumination device and an electro-optical device using a light guide plate and a light emitting element.

  Conventionally, a planar illumination device used for a backlight of an electro-optical device such as a liquid crystal display device has been widely used. The planar illumination device includes a plurality of light emitting diodes (hereinafter referred to as LEDs) as light sources and a light guide plate.

By arranging the light emitting surfaces of the plurality of LEDs to face the light incident surface of the light guide plate and making light incident on the light guide plate, the light guide plate emits light from a predetermined light emitting surface. A conventional light guide plate is a plate-like member formed in a square shape, and is arranged so that the light emitting surfaces of a plurality of LEDs face the entrance surface of the light guide plate (see, for example, Patent Document 1).
JP 2002-163915 A

  However, in the conventional planar lighting device, a plurality of LEDs are aligned along one side, which is the light incident surface of the rectangular light guide plate. Due to the terminal portions, etc., a plurality of LED chips could not be densely arranged. Therefore, when a large amount of light is required, a necessary number of LED chips cannot be arranged on the light guide plate.

SUMMARY An advantage of some aspects of the invention is that it provides an illumination device and an electro-optical device in which many light-emitting elements can be arranged with respect to a light guide plate.
In the lighting device of the present invention, each light emitting surface faces the light guide plate having a plurality of uneven portions formed on the side surface portion serving as a light incident surface, and the plurality of concave portions and the plurality of convex portions in the plurality of uneven portions. And a plurality of light emitting elements provided as described above.
According to such a structure, many light emitting elements can be arrange | positioned with respect to a light-guide plate.

The lighting device of the present invention further includes a substrate on which the plurality of light emitting elements are provided on the surface, and the terminal portions of adjacent light emitting elements among the plurality of light emitting elements are not overlapped on the substrate. It is desirable that they are arranged.
According to such a structure, many light emitting elements can be arrange | positioned with respect to a light-guide plate, without the terminal part of an adjacent light emitting element colliding.

In the illumination device according to the aspect of the invention, it is preferable that the surface of each side surface portion of the uneven portion is perpendicular to the surfaces of the end surface portions of the plurality of concave portions and the end surface portions of the plurality of convex portions.
According to such a structure, it becomes possible to arrange | position more light emitting elements.

The electro-optical device of the present invention includes the illumination device of the present invention and a display panel having a light transmission portion that transmits light emitted from the illumination device.
According to such a configuration, the display panel can display an image with higher luminance.

Embodiments of the present invention will be described below with reference to the drawings.
First, the configuration of the electro-optical device according to the present embodiment will be described with reference to FIG. FIG. 1 is an exploded perspective view showing the configuration of the electro-optical device according to the present embodiment. As shown in FIG. 1, a liquid crystal display device 1 as an electro-optical device includes a display panel 2 including a liquid crystal device and an illumination device 3.

  More specifically, a flexible printed circuit board (hereinafter referred to as FPC) 4 is connected to the display panel 2. The display panel 2 is configured by bonding two glass substrates 2a and 2b and sealing liquid crystal between the two glass substrates 2a and 2b. The liquid crystal modulates light by changing the orientation and order of the molecular assembly according to the voltage level applied to each pixel. Using such characteristics of the liquid crystal, the display panel 2 can display an image on the display region 2c in which the liquid crystal is sealed, based on the image signal supplied from the FPC 4. For this purpose, various circuit elements such as switching elements and signal lines for image display are formed on the two glass substrates 2a and 2b.

  The illumination device 3 includes a rectangular light guide plate 5 and a plurality of LEDs 6 as light emitting elements. The LED 6 is a chip-type LED. A diffusion sheet 7 is disposed on the light exit surface of the light guide plate 5. A plurality of LEDs 6 are arranged on one side surface which is a light incident surface of the light guide plate 5. The arrangement configuration of the plurality of LEDs 6 in the illumination device 3 will be described later. The display panel 2 and the lighting device 3 are accommodated in a box-shaped case 8 having an opening surface.

  Next, the configuration of the illumination device 3 will be described in detail. FIG. 2 is a plan view of the lighting device 3. FIG. 3 is a partial perspective view of the lighting device 3. FIG. 4 is a perspective view for explaining the configuration of the LED 6.

  A plurality of concave and convex portions are formed on one side surface portion that is a light incident surface of the light guide plate 5. A plurality of LEDs 6 are respectively disposed in the plurality of recesses 5a of the plurality of uneven portions, and a plurality of LEDs 6 are also disposed on the plurality of protrusions 5b of the plurality of uneven portions.

  As shown in FIG. 2, the shape of each concavo-convex portion on one side surface portion of the light guide plate 5 is a rectangular wave shape in cross section along a plane parallel to the light emitting surface of the light guide plate 5. In other words, each concave portion is a portion in which one side surface portion is cut out at equal intervals at a plurality of locations. In other words, each convex portion is a portion protruding at regular intervals on one side surface portion.

  As shown in FIG. 3, the plurality of LEDs 6 are soldered onto a substrate, here, one surface of the FPC 9. The FPC 9 is pinned to the light guide plate 5 or attached by an adhesive. On the FPC 9, a plurality of wirings (not shown) for supplying a current to each LED 6 and a plurality of terminal parts (not shown) for electrical connection with the terminal part 6a of each LED 6 are formed. Has been.

  As shown in FIG. 4, each LED 6 has a substantially rectangular parallelepiped shape, and one surface of the rectangular parallelepiped (a surface indicated by hatching in FIG. 4) is a light emitting surface 6 b. Since the light exit surface 6b has a slightly larger area than the opposite surface 6g, the LED 6 has a slightly trapezoidal shape when viewed from the direction orthogonal to the surface of the FPC 9.

  Each LED 6 emits light as indicated by an arrow from the surface of the light emitting surface 6b. Two terminal portions 6a are provided on a surface composed of four surfaces 6c, 6d, 6e, and 6f in contact with the rectangular light emitting surface 6b. The two terminal portions 6a are provided so as to protrude from the surface, respectively. In FIG. 4, the two terminal portions 6a are provided so as to extend not only to the surfaces of the two surfaces 6d and 6f but also to the surface of the surface 6e. The terminal portion (not shown) of the FPC 9 and the two terminal portions 6a are electrically connected to each other by being soldered.

  Furthermore, as shown in FIG. 3, the plurality of LEDs 6 are arranged corresponding to the plurality of concave portions 5 a and convex portions 5 b, respectively. Some LEDs 6 of the plurality of LEDs 6 are arranged so as to enter the plurality of recesses 5a with the light emission surfaces facing the base end face portions 11 in the plurality of recesses 5a. The remaining part of the plurality of LEDs 6 is disposed so that the light emission surface faces the front end surface portion 12 of the plurality of convex portions 5b.

  As described above, since the shape of each uneven portion is a rectangular wave shape along the plane parallel to the light emitting surface of the light guide plate 5, the surface of each side surface portion of each uneven portion is It is orthogonal to the respective surfaces of the base end face part 11 in the plurality of recesses 5a and the tip end face part 12 of the plurality of protrusions 5b, that is, at right angles. Therefore, it becomes possible to arrange more LEDs 6 on the light exit surface of the light guide plate 5.

  Therefore, when the FPC 9 is pinned to the light guide plate 5 or attached by an adhesive, each LED 6 has each terminal portion 6a electrically connected to each terminal portion on the FPC 9, and the base end surface of the recess 5a or It arrange | positions on FPC9 so that a light-projection surface may be made to oppose the front end surface of the convex part 5b.

According to such a configuration, more LEDs 6 can be provided on one side surface that is the light incident surface of the light guide plate 5 than in the past, so that the amount of light emitted from the light output surface of the light guide plate 5 is increased. .
FIG. 5 is a diagram for explaining the difference between the conventional lighting device and the lighting device according to the present embodiment. FIG. 5A is a partial plan view for explaining the arrangement of LEDs in a conventional lighting device. FIG. 5B is a partial plan view for explaining the arrangement of the LEDs in the lighting apparatus according to the present embodiment.

  In the conventional illumination device, the plurality of LEDs 56 are arranged side by side on a straight line L1 along the surface of one side surface that is the light incident surface of the light guide plate 55. That is, the plurality of LEDs 56 are arranged linearly. Since the terminal portions 56a at both ends of each LED 56 protrude from the side surface portion of the LED 56, a plurality of adjacent LEDs 56 are separated from each other by at least the length of the protruding terminal portion 56a in the straight line L1 direction. It was necessary to secure a distance d1 between the LEDs 6.

  On the other hand, in the illuminating device 3 according to the present embodiment, the plurality of LEDs 6 have two straight lines along the concave and convex portions 5a and 5b of the concave and convex portions on one side surface that is the light incident surface of the light guide plate 5. They are arranged side by side on L2 and L3, in other words, in a so-called staggered pattern. The two straight lines L2 and L3 that respectively pass through the terminal portion 6a of the LED 6 are separated from each other by a distance D.

Therefore, when the light guide plate 55 is viewed along the surface of one side surface that is a light incident surface and from a parallel direction, the light guide plate 55 is provided on the terminal portions 6a and the convex portions 5b of the plurality of LEDs 6 provided in the concave portions 5a. The plurality of LEDs 6 are arranged on the surface of the FPC 9 so as not to overlap with the terminal portions 6a of the LEDs 6. In other words, the plurality of LEDs 6 are arranged on the FPC 9 so that the terminal portions 6a of the adjacent LEDs 6 among the plurality of LEDs 6 are located on different lines. In other words, the terminals 6a of the adjacent LEDs 6 are arranged on the FPC 9 so as not to overlap.
The distance D may be a distance that does not cause contact between the terminal portions 6a of the adjacent LEDs 6, that is, does not overlap.

  Therefore, in the illumination device 3 according to the present embodiment, when viewed from the direction orthogonal to the light incident surface of the light guide plate 5, the distance d2 between the adjacent LEDs 6 is the distance d1 between the adjacent LEDs 56 in the conventional illumination device. Can be shorter. As a result, since the lighting device 3 can use more LEDs than the conventional device, the display panel 2 can display an image with higher luminance in the display region 2c which is a light transmission portion. . In other words, the lighting device 3 of the present embodiment can provide more LEDs than the conventional lighting device with respect to the light guide plate having the same dimensions.

As described above, according to the present embodiment, it is possible to realize an illuminating device and an electro-optical device that can arrange a large number of light emitting elements with respect to a light guide plate.
Note that the illumination device according to this embodiment can be applied not only to the backlight illumination device of the liquid crystal display device as described above but also to various general illumination devices.

  Furthermore, the lighting device according to the present embodiment includes not only a passive matrix liquid crystal display device but also an active matrix liquid crystal display device (for example, a TFT (thin film transistor) or a TFD (thin film diode)) as a switching element. The present invention can be similarly applied to a display panel of a liquid crystal display panel). In addition to the liquid crystal display panel, the illumination device according to this embodiment can be similarly applied to various display panels such as an electroluminescence device and an organic electroluminescence device.

  The present invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the scope of the present invention.

FIG. 3 is an exploded perspective view illustrating a configuration of the electro-optical device according to the present embodiment. The top view of the illuminating device concerning embodiment of this invention. The fragmentary perspective view of the illuminating device concerning embodiment of this invention. The perspective view for demonstrating the structure of LED concerning embodiment of this invention. The figure for demonstrating the difference between the conventional illuminating device and the illuminating device which concerns on this Embodiment.

Explanation of symbols

1 liquid crystal display device, 2 display panel, 3 lighting device, 4,9 flexible printed circuit board, 5,55 light guide plate, 56,6 LED

Claims (4)

A light guide plate having a plurality of concave and convex portions formed on a side surface portion serving as a light incident surface;
A plurality of light emitting elements provided so that each of the light exit surfaces faces the plurality of concave portions and the plurality of convex portions in the plurality of concave and convex portions,
A lighting device comprising: And further comprising a substrate on which the plurality of light emitting elements are provided,
The lighting device according to claim 1, wherein the lighting device is disposed on the substrate such that terminal portions of adjacent light emitting elements among the plurality of light emitting elements do not overlap.   The lighting device according to claim 2, wherein the surface of each side surface portion of the concavo-convex portion is perpendicular to the surfaces of the end surface portions of the plurality of concave portions and the end surface portions of the plurality of convex portions. The lighting device according to any one of claims 1 to 3,
An electro-optical device comprising: a display panel having a light transmission portion that transmits light emitted from the illumination device.

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