JP2002109942A - Backlight unit and display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a backlight unit and a display device having a brightness improved by relatively simple construction. SOLUTION: An LED 1 is mounted on and electrically connected to a substrate 2, and other components like ICs and resistors are also mounted on the substrate 2. A hole part 31 is formed to a light guide means 3. The hole part 31 is formed so as to put and surround the LED 1 an its approximate central part. A light guide plate 4 is made of transparent acryl resin on which, a light incidence plane 41 formed so as to face a light outgoing opening 32, and a light outgoing plane 42 from which, the light got in the light incidence plane 41 is going out, are formed. An opening of the device main body 6 (not shown in the figure) is formed rectangular and a display part 5 is installed at the opening. According to this form of practice, as the LED is surrounded, and the hole part 31 having the light outgoing opening 32 is formed at the opposite side of the substrate 2, and the light guide means 3 is formed on the substrate 2, the light emitted from the LED is enabled to efficiently get into the light guide plate 4, and the brightness at the display part 5 is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a backlight unit and a display device.

2. Description of the Related Art In a backlight unit using a point light source, particularly an LED, a side light system in which a display unit is illuminated by using light guide means is often used. The sidelight method is to irradiate a display unit by making light incident from an end face of a light guide means such as a light guide plate, propagating incident light to one surface substantially orthogonal to the end surface, and emitting light from this one surface. is there.

In response to such a tendency, for example,
The thing described in -344705 is known. In this prior art, an extended portion is formed on a light incident surface of a light guide plate as a light guide means so as to be provided near an LED provided on a substrate. Thereby, the light from the LED can be effectively guided to the light guide plate from the lower surface of the extending portion and can be efficiently emitted.

However, according to the prior art, the production of the light guide plate for forming the extension is complicated, and a space is formed at the place where the extension and the LED are provided. Since the light emitted from the LED is absorbed by the light guide, there is a limit to the light incident on the light guide plate, and there is a limit in improving the brightness of the display unit provided immediately above the light exit surface of the light guide plate. there were.

[0003] The present invention has been made in view of the above problems, and an object of the present invention is to provide a backlight unit and a display device in which luminance is improved with a relatively simple configuration.

A backlight according to claim 1 includes a point light source; a substrate on which the point light source is provided and on which electronic components are mounted; A light introducing means provided on a substrate, having a hole having a light projecting opening formed on a side thereof; a light incident surface and a light exit from which light incident from the light incident surface propagates to emit light A light guiding means having a light incident surface facing the light projecting opening of the hole of the light introducing means; and a display part being provided on the light emitting surface side of the light guiding means. And;

In the present invention, the definitions and technical meanings of terms are as follows unless otherwise specified.

The point light source preferably uses an LED, but is not particularly limited as long as a desired light distribution can be obtained.

The substrate has a point light source mounted thereon and an IC.
And electronic components such as resistors and the like, and more preferably all electronic components necessary for the operation of the backlight unit are mounted, but at least a point light source is provided. If it is not limited.

The light introducing means is not particularly limited as long as the light introducing means is formed so that the light emitted from the point light source is incident on the light incident surface of the light guiding means.
Preferably, the light emitted from the point light source to the inner wall of the hole is diffused and reflected in the direction of the light incident surface.

The light guiding means has a function as a planar light source for optically propagating the light incident from the light incident surface inside and emitting the light from the light emitting surface. There is no particular limitation. For example, a light guide system such as a hollow system in which the light guide unit is formed by the reflection unit and the transmission unit is also allowed.

As a preferable light guide means, a light guide plate made of a synthetic resin is used. Further, the shape of the light guide plate is desirably a flat plate, but may be any shape as long as it does not depart from the gist of the present invention.

[0010] The light guide plate may be provided with a reflection means on the surface opposite to the light exit surface. This reflecting means can be formed by sticking a silver sheet or a white resin sheet having a high reflectivity, or by applying a white pigment or the like to the light guiding means. Further, a reflector having a high reflectance may be provided separately from the light guide plate.

The display section may be any display means such as a translucent flat display panel. The display section is illuminated with light from a point light source and displays characters, designs, images or images. And a liquid crystal display means formed by printing a desired paint on a translucent resin, glass, or the like, or a liquid crystal display means, but the material and structure are not particularly limited.

In the backlight unit of the first aspect, first, light emitted from a point light source provided on the substrate is diffusely reflected in the light introducing means and is incident on the light incident surface of the light guiding means.
Light incident from the light incident surface propagates inside the light guide means. Then, light is emitted from the light emission surface of the light guide means and irradiates the display unit.

According to the first aspect of the present invention, there is provided a light introducing means provided on the substrate, having a hole surrounding the point light source and having a light projecting opening formed on the side opposite to the substrate. Therefore, light from the point light source can be efficiently incident on the light guide means, and the luminance of the display unit can be improved.

According to a second aspect of the present invention, in the backlight unit, the light introducing means is formed of a highly reflective member.

The light introducing means is preferably formed of a highly reflective member so that light emitted from the point light source is applied to the inside of the hole and diffusely reflected on the inner surface of the hole. In this case, it may be formed by mixing a translucent resin such as polycarbonate or acrylic with a member having high reflection characteristics such as titanium oxide, or may be formed of a milky white resin.

According to the second aspect of the present invention, the light introducing means includes:
Since it is formed of a highly reflective member, light from a point light source can be more effectively incident on the light guide means, and the luminance of the display unit can be improved.

According to a third aspect of the present invention, there is provided the backlight unit according to the first or second aspect, wherein a curved portion is formed on a surface of the light guide that faces the light incident surface. .

According to the third aspect of the present invention, since the curved portion is formed on the surface of the light guide means facing the light incident surface, light incident from the light incident surface is totally reflected at the curved portion. Therefore, the light can be more efficiently propagated in the light guide means and the luminance and the luminance uniformity of the display unit can be improved.

According to the backlight unit of the fourth aspect, in the backlight unit according to any one of the first to third aspects, the hole of the light introducing means is formed so that the light guide means side is larger than the substrate side. It is characterized by having been done.

According to the fourth aspect of the present invention, since the hole of the light introducing means is formed so that the light guide means side is larger than the substrate side, the light radiated from the point light source into the hole is formed. The light can be more easily incident on the light incident surface of the light guide means, and the luminance of the display unit can be improved.

The display device of claim 5 is the display device of claim 1 or 4
A backlight unit according to any one of the above, and a device main body in which the backlight unit is provided and in which the lighting device is housed.

The main body of the apparatus is preferably provided with an opening for providing a display section, and the shape, structure, material and the like are not limited.

According to the fifth aspect of the present invention, it is possible to obtain a display device having the function of any one of the first to fourth aspects.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an enlarged side sectional view showing a main part of a display device according to a first embodiment of the present invention, and FIG. 2 is a top view showing the same light introducing means.

In each of the figures, reference numeral 1 denotes an LE as a point light source.
D, 2 are substrates, 3 is light introducing means, 4 is a light guide plate as light guiding means, and 5 is a display unit.

The LED 1 is conductively mounted on a substrate 2 which will be described later.
Are arranged.

The substrate 2 has a flat plate shape, and is provided on a bottom portion 61 of the apparatus main body 6 described later. This substrate 2 has LE
In addition to D1, an IC, a resistor, and the like are mounted, and electronic components necessary for the function of the display device of the present embodiment are mounted.

The light introducing means 3 has a hole 3 as shown in FIG.
1 is provided, and is formed of a mixed material obtained by mixing titanium oxide with polycarbonate.

The hole 31 is formed in a rectangular shape such that the LED 1 is provided substantially at the center on the substrate 2 side.
It is formed so as to surround.

Further, as shown in FIG. 1, the aperture 31 is formed so that the light guide plate 4 side is larger than the substrate 2 side.
2 is formed in a rectangular shape.

The light guide plate 4 is made of a transparent acrylic resin, and is provided with a light incident surface 41 provided so as to face the light projecting opening 32 of the hole 31, and the light incident from the light incident surface 41 is propagated. A light exit surface 42 from which the light exits is formed.

A curved portion 43 is formed so as to be continuous from one end of the light incident surface 41 so as to face the light incident surface 41.

A light diffusing sheet 7 is attached to the light exit surface 42 for improving the brightness.

Further, a plurality of concave and convex portions (not shown) are formed in a desired pattern on the surface on the opposite side of the light emitting surface 42 as luminance equalizing means. This uneven portion may be formed directly on the light guide plate 2, or the reflection control member may be provided separately using dot printing or the like.

The display section 5 has a pair of molecular alignment films (not shown) disposed between a pair of transparent electrodes (not shown) formed in a matrix. A liquid crystal (not shown) is provided in the
The display unit 5 has a light guide plate 4 as shown in FIG.
Are provided on the side of the light emitting surface 42.

The device body 6 is made of a synthetic resin having a high reflectivity, and has an opening (not shown) having a rectangular shape. The display unit 5 is provided in this opening.

The reflecting plate 8 is a metal flat plate, and is provided at a position facing the light exit surface 42 of the light guide plate 4.

In the first embodiment, first, the light emitted from the LED 1 provided on the substrate 2 is diffused and reflected in the light introducing means 3 to distribute the light incident on the light incident surface of the light guide plate 4. Spread the characteristics. Then, light incident from the light incident surface 41 of the light guide plate 4 propagates inside the light guide plate 4 by being totally reflected by the curved portion 43. Then, light is emitted from the light emission surface 42 of the light guide plate 4 and irradiates the display unit 5.

According to the first embodiment, the light introducing means provided on the substrate 2 has the hole portion 31 surrounding the LED 1 and having the light projecting opening 32 formed on the side opposite to the substrate 2 side. Since the light source 3 is provided, the light from the LED 1 can be efficiently incident on the light guide plate 4, and the brightness of the display unit 5 can be improved.

Further, since the light introducing means 3 is formed of a highly reflective member, the light from the LED can be more effectively incident on the light guide plate 4 and the brightness of the display unit 5 can be improved. .

Further, since the curved portion 43 is formed on the surface of the light guide plate 4 facing the light incident surface 41, the light incident from the light incident surface 41 is totally reflected by the curved portion 43. The light can be efficiently transmitted to the light guide plate 4 and the luminance and the luminance uniformity of the display unit 5 can be improved. Furthermore, since the hole 31 of the light introducing means 3 is formed so that the light guide plate 4 side is larger than the substrate 2 side, the LED 1
The light applied to the inside of the hole 31 is more easily incident on the light incident surface 41 of the light guide plate 4, and the brightness of the display unit 5 can be improved.

Next, a second embodiment will be described with reference to FIG.

Numeral 9 denotes a light introducing means. The same components as those shown in FIG. 1 or FIG.

The light introducing means 9 has a hole 9 as shown in FIG.
1 is provided, and is formed of a mixed material obtained by mixing titanium oxide with polycarbonate.

The hole 91 is formed in a substantially circular shape such that the LED 1 is provided substantially at the center of the substrate 2.
It is formed so as to surround.

Further, as shown in FIG. 1, the hole 91 is formed so that the light guide plate 4 side is larger than the substrate 2 side.
2 is formed in a circular shape.

The second embodiment has the same effect as the first embodiment.

The first and second embodiments are more suitable for a small display device such as a mobile phone, and all the systems necessary for the function of such a display device are provided on the substrate 2.
Therefore, a display device using the LED 1 that can be easily formed and can improve luminance can be realized.

[0049]

According to the first aspect of the present invention, the light introducing means provided on the substrate has a hole surrounding the point light source and having a light projecting opening on the side opposite to the substrate. Since the light source is provided, light from the point light source can be efficiently incident on the light guide means, and the luminance of the display unit can be improved.

According to the second aspect of the present invention, the light introducing means is:
Since it is formed of a highly reflective member, light from a point light source can be more effectively incident on the light guide means, and the luminance of the display unit can be improved.

According to the third aspect of the present invention, since the curved portion is formed on the surface of the light guide that faces the light incident surface, light incident from the light incident surface is totally reflected at the curved portion. Therefore, the light can be more efficiently propagated in the light guide means and the luminance and the luminance uniformity of the display unit can be improved.

According to the fourth aspect of the present invention, the hole of the light introducing means is formed so that the light guide means side is larger than the substrate side, so that the light radiated from the point light source into the hole is formed. The light can be more easily incident on the light incident surface of the light guide means, and the luminance of the display unit can be improved.

According to the fifth aspect of the present invention, it is possible to obtain a display device having the function of any one of the first to fourth aspects.

[Brief description of the drawings]

FIG. 1 is an enlarged side sectional view of a main part showing a display device according to a first embodiment of the present invention.

FIG. 2 is a top view showing the light introducing means 3 of the display device.

FIG. 3 is a top view showing a light introducing unit 9 according to a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... LED as point light source, 2 ... board | substrate 3, 9 ... light introduction means, 4 ... light guide plate which is light guide means, 5 ... display part,

Claims (5)

[Claims] A point light source; a substrate on which the point light source is provided and the electronic component is mounted; and a hole surrounding the point light source and having a light projecting opening formed on the side opposite to the substrate side. A light introducing means provided on the substrate; and a light incident surface and a light emitting surface from which light incident from the light incident surface propagates to emit light, wherein the light incident surface is the light introducing means. And a display unit provided on the light exit surface side of the light guide unit. Backlight unit. 2. The backlight unit according to claim 1, wherein the light introducing means is formed of a highly reflective member. 3. The backlight unit according to claim 1, wherein a curved portion is formed on a surface of the light guide that faces the light incident surface. 4. The backlight unit according to claim 1, wherein the hole of the light introducing means is formed so that the light guide means side is larger than the substrate side. 5. A display device comprising: the backlight unit according to claim 1; and a device main body provided with the backlight unit and containing a lighting device.