JP2002231028A - Lighting apparatus and liquid crystal display unit using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lighting apparatus with which a dark spot emerging in the vicinity of the side end face of a light guiding body of an electric discharge tube is alleviated and brightness of light discharged from the light guiding body is virtually made uniform, and to provide a liquid crystal display unit using the same. SOLUTION: A light guiding body 5 is composed of two pieces of cuneiform light guiding members 5a and 5b whose inclined planes are polymerized one upon the other to form a shape of cuboid and straight electric discharge tubes 4a and 4b are arranged closely alongside the thick end faces of respective light guiding members. In addition, light reflex bodies 6a and 6b which reflect the light emitted from both discharge tubes 4a and 4b are arranged together with a light reflex board 7 set under the light guiding body 5 and an optical transducer member 8 set above the light guiding body 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illuminating device having an improved configuration of a light guide and a liquid crystal display device such as a personal computer or a word processor using the illuminating device.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 3, for example, as shown in FIG. 3, a straight tube-shaped discharge tube 4 is arranged close to a side end surface of a thick portion of a wedge-shaped light guide 5 and a discharge tube is formed. A light reflector 6 having a U-shaped cross section is provided so as to surround the tube 4, and a light reflector 7 is attached below the light guide 5 along an inclined surface on a lower surface of the light guide 5, and a light guide is provided. A light diffusing plate 8 as a light conversion member is attached above the body 5 along a flat surface on the upper surface of the light guide 5.

The light reflector 6 has on its inner surface facing the discharge tube 4 a light reflection surface for reflecting the light emitted from the discharge tube 4. The light enters from the side end face of the light guide 5 facing the discharge tube 4 and is guided inside, and the light passing through the lower surface 5 of the light guide 5 is reflected by the light reflection plate 7 on the flat surface side of the light guide 5. The light is again incident on the light guide 5 and is diffused by the light diffusion plate 8 and emitted to the outside.

[0004]

In general, the luminous characteristics of the discharge tube 4 are such that the luminous intensity at both ends of the discharge tube 4 is small and the luminous intensity at the central portion is high. Dark portions A, A are formed at both corners near the side end surface of the light guide 5 where the light emitted from the tube 4 is incident, and the problem that the brightness of the light emitted from the emission surface of the light guide 5, that is, the flat surface is not uniform. There is.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in view of the above problems, and alleviates a dark portion generated near a side end face of a light guide of a discharge tube to substantially uniform the luminance of light emitted from the light guide. It is an object of the present invention to provide an illuminating device which can be used and a liquid crystal display device using the same.

[0006]

In order to solve the above-mentioned problems, a lighting device according to the present invention is characterized in that a light guide is formed by overlapping two inclined surfaces of two wedge-shaped light guide members. The discharge tubes each have a straight tube shape and are arranged close to each other along the thick side end surfaces of the respective light guide members, and light emitted from both of the discharge tubes is reflected to be incident on the light guide. And a light reflecting plate is provided on the lower surface of the light guide, and a light converting member is provided on the upper surface of the light guide.

Accordingly, the direct light of one discharge tube and the light reflected by the light reflector enter the one light guide member from the thick portion of the light guide member, and the direct light of the other discharge tube and The light reflected by the light reflector is incident from the thin portion side of the one light guide member, and the other light guide member receives the direct light of the other discharge tube and the light reflected by the light reflector at the thickness of the light guide member. The direct light of one discharge tube and the light reflected by the light reflector are incident from the thin portion side of the other light guide member.

For this reason, the dark portions near the side end surfaces of the thick portions of both light guide members, which are generated because they cannot be compensated for by the direct light and the reflected light thereof, are supplemented by the direct light of the opposed discharge tube and the reflected light thereof. Will be removed. Therefore, a large amount of light emitted from the discharge tube is introduced into both light guide members, and from the entire emission surface of the light guide,
Emission light having a substantially uniform density is emitted, and high luminance and high illuminance are obtained.

Further, in the illumination device according to a second aspect of the present invention, the flat surfaces of the two rectangular parallelepiped light guide members are overlapped to form a rectangular parallelepiped light guide, and a pair of parallel two side end faces is provided. Are arranged close to each other along a straight line, so that a dark portion generated near a pair of parallel side end surfaces can be removed.

According to a third aspect of the present invention, a liquid crystal display device having a stable luminance can be obtained by using the illumination device according to the first or second aspect.

[0011]

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

The lighting device according to the embodiment is shown in FIGS.
As shown in FIG. 1, a chassis 1 having reflector side bent portions 2 and 2 formed on the left and right sides of the substrate and light guide side bent portions 3 and 3 formed before and after the substrate. Straight discharge tubes 4a, 4b provided in parallel on both right sides
A rectangular parallelepiped light guide 5 provided between the two discharge tubes 4a and 4b, and a light reflector 6a and 6b having a U-shaped cross-section arranged close to the back side of the two discharge tubes 4a and 4b; Chassis 1
And a light diffusing plate 8 as a light converting member mounted over the reflector side bent portions 2 and 2 of the chassis 1.

The reflector-side bent portions 2 and 2 of the chassis 1
Has an inverted L-shaped cross section, and a vertical plate 2a in a vertical direction,
A light reflector 6a, 6 of the discharge tubes 4a, 4b by a vertical plate 2a and a horizontal plate 2b.
b, and the horizontal plate 2 of both reflector side bent portions 2
An upper surface opening B is formed between b and 2b.

Light guide side bent portions 3 and 3 of the chassis 1
Are formed by vertical plates 3a in the vertical direction, gaps C, C are formed between the vertical plates 3a of the light guide side bent portion 3 and the vertical plates 2a of the reflector side bent portion 2, and the light guide is formed. Gaps D, D are formed between the vertical plate 3a of the body-side bent portion 3 and the horizontal plate 2b of the reflector-side bent portion 2.

The light diffusing plate 8 is exposed from the upper opening B, both ends of the two discharge tubes 4a, 4b and both reflectors 6a, 6b are exposed in the gap C, and both reflectors 6a, 6b are exposed in the gap D. The joint between the light diffusion plate 6b and the light diffusion plate 8 is exposed.

Further, in one of the gaps C, a support plate member 9a having an L-shaped cross section is fixed to both left ends of the substrate of the chassis 1, and in the other gap C, the reflector-side bent portion is provided. A support member 9b having the same shape as the support member 9a is fixed to both ends of the second horizontal plate 2b.

The light guide 5 is made of, for example, acrylic resin,
Made of synthetic material of transparent resin such as polycarbonate,
The inclined surfaces of the two wedge-shaped light guide members 5a and 5b are brought into surface contact with each other so that the rectangular side end surfaces of the thick portions face each other, and the rectangular parallelepiped light guide 5 is formed. Have been.

One discharge tube 4a is supported between the support members 9a, 9a and the reflector 6a, and the other discharge tube 4b is supported between the support members 9b, 9b and the reflector 6b. The two discharge tubes 4a and 4b are arranged along the rectangular side end surfaces of the thick portions of the parallel light guide members 5a and 5b. Side end surfaces of the light guide members 5a and 5b are
a, 4b are composed of short sides and long sides having lengths slightly larger than the diameters and the axial lengths.

The light reflectors 6a and 6b can be made of either metal or resin. The inner surfaces of the semicircular arcs surrounding the discharge tubes 4a and 4b, that is, the reflecting surfaces have white reflecting layers. Are formed (not shown).

The light reflecting plate 7 straddles the lower linear edge of both light reflectors 6a and 6b below the light guide 5 and is equal to or slightly larger than the lower surface of the light guide 5. Has an area. In addition, the light diffusion plate 8 straddles the linear edge on the upper side of both the light reflectors 6 a and 6 b above the light guide 5, and has an area equal to or slightly larger than the upper surface of the light guide 5. Have.

The direct light from one discharge tube 4a is incident on the side end surface of the thick portion of one light guide member 5a, and the discharge tube reflected by the reflection surface of one light reflector 6a. The reflected light of 4a is incident on the side end surface of the thick portion of one light guide member 5a. Further, the direct light and the reflected light of the other discharge tube 4b are also incident from the side end surface of the thin portion of the one light guide member 5a.

Further, the direct light of the other discharge tube 4b enters from the side end face of the thick portion of the other light guide member 5b, and is reflected by the other light reflector 6b. Is reflected from the side end surface of the thick portion of the other light guide member 5b, and the direct light and the reflected light of one discharge tube 4a are further incident on the side end surface of the thin portion of the other light guide member 5b. Incident from.

Therefore, the inside of the light guide 5 is provided between the two discharge tubes 4.
The light incident on the discharge tube 4b is alleviated by the incident light of the other discharge tube 4b, and the dark portion generated near the side end surface of the thick portion of the one light guide member 5a is reduced. The dark part near the side end face of the thick part of the optical member 5b is alleviated by the incident light of the one discharge tube 4a. As a result, the luminance of the light emitted from the light emitting surface of the light guide 5 is substantially uniform, and the luminance unevenness is eliminated, and the synthesized light is emitted to the outside through the light diffusion plate 8. , High illuminance can be obtained.

The light guide 5 is formed in a rectangular parallelepiped shape by inclining the inclined surfaces of two wedge-shaped light guide members 5a and 5b, but is formed in a rectangular parallelepiped light guide member of two thin plates. The light guides 5 having a rectangular parallelepiped shape may be formed by bringing the flat surfaces of the above into surface contact with each other.

In the case of the above embodiment, the light reflector 6
Although the materials of a and 6b are not specified, any of metals and resin materials can be used. However, it is preferable to use a metal thing from the point of strength.

Further, if a liquid crystal display element is arranged above the light diffusing plate 8 of the lighting device, the present invention can be applied to a liquid crystal display device.

The light converting member is not limited to the one formed only by the light diffusing plate 8 but also includes the light diffusing plate 8.
And a prism sheet disposed above the light diffusion plate 8.

[0028]

As described above, in the lighting device according to the present invention, the light guide, the inclined surfaces of the two wedge-shaped light guide members are parallel to each other, and the rectangular side end surfaces of the thick portions are parallel to each other. The direct discharge lamp and the reflected light of both discharge tubes can be combined, and the discharge tubes are opposed to each other. This is effective for removing the dark portion generated near the side end surface of the light guide member to make the luminance uniform.

In the liquid crystal display device according to the present invention, a rectangular parallelepiped light guide is formed by superposing two wedge-shaped or rectangular parallelepiped light guide members, and the light guide is formed along a pair of parallel side end surfaces. Since a lighting device having a tube-shaped discharge tube is used, the liquid crystal display screen can be irradiated with substantially uniform luminance.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a lighting device according to an embodiment of the present invention.

FIG. 2 is a perspective view of the lighting device according to FIG. 1;

FIG. 3 is a cross-sectional view of a lighting device showing a conventional example.

FIG. 4 is a plan view showing a light emission state of the upper surface of the light guide of the conventional lighting device of FIG. 3;

[Explanation of symbols]

 4a, 4b Discharge tube 5 Light guide 5a, 5b Light guide 6a, 6b Light reflector 7 Light reflector 8 Light conversion member (light diffuser)

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G02F 1/13357 G02F 1/13357 // F21Y 103: 00 F21Y 103: 00

Claims (3)

[Claims] 1. The first light-transmissive light-guiding member includes a first end portion and a second end portion. A rectangular parallelepiped light guide formed by superposing the respective inclined surfaces of the first and second light guide members, and a straight pipe disposed close to and along the side end surface of the thick portion of the first light guide member A first discharge tube having a shape, and a second tube having a straight tube shape which is positioned close to the second light guide member along a side end surface of a thick portion of the second light guide member.
, A first light reflector for reflecting light emitted from the first discharge tube and causing the light to enter the light guide, and a light guide reflecting light emitted from the second discharge tube. The second to make light incident on the body
An illumination device, comprising: a light reflector of (1), a light reflector disposed on a lower surface of the light guide, and a light conversion member disposed on an upper surface of the light guide. 2. A light guide formed by superimposing a light-transmitting rectangular parallelepiped first light guide member and a light-transmitting rectangular parallelepiped second light guide member; A first discharge tube in the form of a straight tube arranged close to and along the side end surface of the light member, and arranged close to and along the side end surface of the second light guide member on the side opposite to the first discharge tube; A second discharge tube having a straight tube shape, and a first discharge tube which reflects light emitted from the first discharge tube and makes light incident on the light guide.
A light reflector, a second light reflector that reflects light emitted from the second discharge tube and makes light incident on the light guide, a light reflector provided on a lower surface of the light guide, A lighting device comprising: a light conversion member provided on an upper surface of a light guide. 3. A liquid crystal display device using the lighting device according to claim 1.