JPH0862429A - Back light - Google Patents

Abstract

PURPOSE: To provide a back light which does not generate irregularity of brightness even when it is used for a long time. CONSTITUTION: A lighting device 1 has a square-shaped frame 2 made of synthetic resin insulator or metal. The frame 2 has a rectangular opening 6 at its center. A light guide body 11 has claw sections 12 at ends on the opposite side to sides of adjacent sides, and the claw section 12 has a V-shaped groove 13 which is opened and expanded toward a tip. A diffusion sheet 14 is provided on a surface of the light guide body 11, and a reflection sheet 15 is provided on a rear surface thereof. Respective ends of a fluorescent lamp 16 bent into an L-shape are fitted into the grooves 13, 13, and cold cathodes 17, 17 are positioned and correspond to the claw sections 12, 12. Even if discoloration or deterioration occurs around the claw section 12 of the light guide body 11 around the cold cathode 17 when the fluorescent lamp 16 is used for many hours, it is possible to prevent the generation of a dark part in the light guide body 11, eliminate irregularity of brightness to realize uniform brightness.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backlight mounted on the back surface of a liquid crystal display board, for example.

[0002]

2. Description of the Related Art Conventionally, as a backlight mounted on the back surface such as a liquid crystal display surface, for example, JP-A-5-19 is known.
No. 6820.

In the structure disclosed in Japanese Patent Laid-Open No. 5-196820, a claw having a V-shaped or U-shaped groove is formed on the side surface of a flat light guide member so as to project therefrom, and the groove of the claw is elongated. A straight tubular fluorescent lamp is held, and the fluorescent lamp is opposed to the side surface of the light guide, and the light emitted from the fluorescent lamp is guided to the light guide to brighten the entire light guide.

[0004]

However, in the case of the structure described in Japanese Patent Laid-Open No. 5-196820, the side surface of the light guide near the electrodes of the fluorescent lamp may be discolored or deteriorated. That is, since the temperature near the electrode of the fluorescent lamp is about 100 ° C., the side surface of the light guide located near the electrode of the fluorescent lamp is exposed to high temperature when the fluorescent lamp is lit, and the side surface of the light guide discolors with time. Or it deteriorates.

If the light guide body is discolored or deteriorated, the amount of light incident from the light guide body in the vicinity of the electrodes of the fluorescent lamp is reduced, which may cause uneven brightness on the surface of the light guide plate. .

The present invention has been made in view of the above problems, and an object of the present invention is to provide a backlight in which uneven brightness is less likely to occur even after long-term use.

[0007]

A backlight according to claim 1, wherein the backlight has a light guide body provided with a locking portion which is disposed so as to face a side surface and which locks a lamp having an electrode, The locking portion is provided at a position corresponding to the electrode of the lamp.

The backlight according to claim 2 is the backlight according to claim 1.
In the backlight described, the light guide is rectangular, the lamp is bent corresponding to the corner of the light guide, each electrode is formed in the vicinity of the end, the locking portion, It is formed on the adjacent sides of the light guide.

The backlight according to claim 3 is the backlight according to claim 1.
In the backlight described above, the light guide has a rectangular shape, and has a notch recess formed in at least one corner and a bent portion locking part formed in the notch recess, and the lamp has the above-mentioned guide. It has an L-shaped bent portion having a length corresponding to each side of the rectangle of the light body, and has a bent portion which is locked to the bent portion locking portion in correspondence with the cutout concave portion, and is provided facing the lamp. The lamp cover is provided with a metal film having a high light reflectance on the surface of the lamp cover facing the lamp.

According to a fourth aspect of the present invention, there is provided a backlight having a light guide body which is provided so as to face a side surface thereof and has a locking portion for locking a lamp having an electrode. It is extended from the longitudinal direction of the side surface of
The electrode is located outside the end of the side surface of the light guide in the longitudinal direction.

The backlight according to claim 5 is the backlight according to claim 4.
In the backlight described above, the light guide has a rectangular shape, the lamp is bent corresponding to a corner of the light guide, and an electrode is formed in the vicinity of an end of each of the lamps. It is formed on the adjacent sides of the light guide.

The backlight according to claim 6 is the backlight according to claim 1.
In the backlight according to any one of items 1 to 5, the lamp has a cylindrical body covering a portion located around the electrode.

[0013]

In the backlight according to the first aspect of the present invention, the light guide has an engaging portion for engaging the lamp, and the engaging portion is provided at a position corresponding to the electrode of the lamp. Even if the temperature rises, the temperature of the locking portion of the light guide body rises, but the temperature of the side surface does not rise significantly, so that discoloration and deterioration of the light guide body can be prevented, and uneven brightness is reduced.

The backlight according to claim 2 is the backlight according to claim 1.
In the backlight described, the lamp is bent corresponding to the corners of the light guide, electrodes are formed in the vicinity of the respective ends, and the locking portions are formed on the adjacent sides of the light guide, Since the light from the lamp travels in the direction intersecting the adjacent sides, even if discoloration or deterioration occurs at the base end part of the locking part, it will be complemented by the other bent part, so uneven brightness will occur. Becomes smaller.

The backlight according to claim 3 is the backlight according to claim 1.
In the backlight described above, the lamp is simplified by engaging the bent portion of the L-shaped bent portion with the bent portion locking portion of the cutout recess formed at the corner of the rectangular light guide. Since a metal film with high light reflectance is deposited on the surface of the lamp cover facing the lamp facing the lamp, a separate reflecting film is not required and the configuration is simplified. .

According to a fourth aspect of the present invention, the lamp is disposed so as to extend from the longitudinal direction of the side surface of the light guide, and the electrode is located outside the end of the side surface of the light guide in the longitudinal direction. Since the high temperature part around the electrode of the lamp hits the part without the light guide, the high temperature part of the electrode does not easily affect the light guide, so it is possible to prevent discoloration and deterioration of the light guide. , Uneven brightness is reduced.

The backlight according to claim 5 is the backlight according to claim 4.
In the backlight described, the lamp is bent corresponding to the corner of the light guide, electrodes are formed near the ends, respectively, and the locking portion is formed on the adjacent side of the light guide. Since the light from each of them travels in the direction intersecting with the adjacent sides, even if the base end part of the locking part is discolored or deteriorated, it is complemented by the other bent part, so that there is uneven brightness. It gets smaller.

The backlight according to claim 6 is the backlight according to claim 1.
In the backlight according to any one of items 1 to 5, the temperature of the electrode is transmitted to the light guide body through the tubular body because the lamp covers the portion located around the electrode with the tubular body. Since the temperature of the light guide does not rise significantly, it is possible to prevent discoloration and deterioration of the light guide,
Brightness unevenness is reduced.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the backlight of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, reference numeral 1 denotes an illuminating device, and the illuminating device 1 has a frame 2 made of an insulating material such as a synthetic resin or made of a metal.

The frame 2 is composed of a pair of L-shaped frame components 3 and 4, and one end of each of the frame components 3 and 4 is rotatably connected by a hinge 5. As shown in FIG. 4, the other end of each of them is fitted and opened by fitting portions 3a and 4a, and when the frame structural bodies 3 and 4 are closed, as shown in FIG. A rectangular opening 6 is formed in the. Further, the frame structure bodies 3 and 4 have the fitting groove 7 formed on the inner peripheral side thereof, and in the closed state, the frame structure bodies 3 and 4 orbit the inner periphery of the frame structure bodies 3 and 4.

Reference numeral 11 denotes a light guide plate, which is made of a transparent or milky white light-transmissive material such as acrylic resin and has a rectangular shape. As shown in FIG. Claws 12 are formed, and claws 12 as locking parts are provided at the ends on the opposite sides of the side surfaces of the adjacent sides. These claws 12 project as shown in FIG. 5 and expand toward the tip. A V-shaped groove portion 13 that opens is formed. Also,
The notch recess 11a of the light guide plate 11 is provided with the bent portion locking portion 10. Furthermore, a diffusion sheet 14 is provided on the surface side of the light guide plate 11.
Is provided, and the reflection sheet 15 is provided on the back surface side.

Further, the claw portions 12 of the light guide plate 11, the groove portions 13 of the 12,
13 has an outer diameter of 3.0 which is bent in an L shape at the bent portion 16a.
Each end of a cold cathode type fluorescent lamp 16 in which a rare gas such as argon is sealed in about mm is fitted. Nickel as an electrode of the fluorescent lamp 16 is fitted to the claw portions 12 and 12. The cold cathodes 17, 17 formed by, for example, correspond to each. As shown in FIG. 6, the fluorescent lamp 16 includes two lamp covers 19 formed in a trough shape with a reflecting surface 19a formed inside and a cushion material 18 respectively, and formed of metal, resin or resin film. By light guide
The portion corresponding to the cold cathode 17 is pressed in 11 directions and fitted into the respective claw portions 12 and 12, and the bent portion 16a is sandwiched by the bent portion locking portion 10 in the notched concave portion 11a of the light guide 11. The fluorescent lamp 16 is fixed to the light guide 11. The lamp cover 19 may be formed of a molded product made of ABS (acrylonitrile butadiene styrene) resin or ABS resin. In this case, for example, if silver or the like is covered by vapor deposition or plating, high light reflection can be easily achieved. Rate reflective surface 19a
Can be formed.

Then, the light guide body in which the fluorescent lamp 16 is mounted
As shown in FIG. 3, 11 is fitted in the fitting groove 7 of the frame 2 and fixed to the frame 2 together with the light guide 11 and the like.

A lighting device 21 such as a variable output high frequency inverter for dimming and lighting the fluorescent lamp 16 is disposed on the back side of the frame structure 4.

Further, on the front side of the frame 2, a liquid crystal display panel 22 to which light is emitted from the back side is attached.

When power is supplied to the fluorescent lamp 16 by the lighting device 21, the fluorescent lamp 16 is lit at high frequency. The light emitted from the fluorescent lamp 16 is reflected directly or in the lamp cover 19 to irradiate the side surface of the light guide plate 11,
Light enters inside from each side surface of the light guide plate 11. The light that has entered the inside travels while being repeatedly reflected inside the light guide plate 11, is reflected by the reflection sheet 15 provided on the back surface side, and is finally irradiated to the front surface side of the light guide plate 11. Then, the liquid crystal display panel 22 is diffused by the diffusion sheet 14 and is uniformly illuminated from the back surface side.

According to the above embodiment, as shown in FIG.
Claws 12, 12 are formed at the farthest end portions of the side faces of the adjacent sides of the light guide plate 11, respectively, and the lamp cover 19 is fitted in the groove 13, 13 of these claws 12, 12 with the fluorescent lamp 16 fitted. , 19 to the light guide plate 11, the fluorescent lamp 16 is pressed and fixed to the groove portion 13 of the claw portion 12 through the cushion material 18, so that the center in the axial direction can be aligned and each side can be aligned. Therefore, the fluorescent lamp 16 can be attached to the light guide plate 11 easily and accurately without any separate positioning.

By using the fluorescent lamp 16 for a long time, for example, as shown in FIG.
Even if discoloration or deterioration occurs around the claw portion 12 of the light guide plate 11 around the cold cathode 17 due to the temperature of about ° C, even if the light L1 from one side weakens and the illumination by the light L1 is dark 11A. Even if occurs, by supplementing the light L2 from the other side, it is possible to prevent a dark portion from occurring in the light guide plate 11 and eliminate variations in brightness, improve the optical characteristics, and make the entire light guide plate 11 uniform. It becomes bright.

Further, in the above embodiment, the groove 13 of the claw 12 is formed.
Although the shape of V is V-shaped, the arc-shaped groove 13a shown in FIG.
The same effect can be obtained with the U-shaped groove 13b shown in FIG. 9 or the U-shaped groove 13c shown in FIG.

Next, another embodiment will be described with reference to FIG.

In the embodiment shown in FIG. 11, the length of the fluorescent lamp 16 is made longer than the length of one side of the light guide 11, and the positions of the cold cathodes 17 and 17 are set from the end of the light guide 11. It is located outside.

As described above, since the cold cathode 17 is not opposed to the light guide body 11, the amount of heat transferred to the light guide body 11 due to the rise of the temperature of the cold cathode body 17 can be reduced. Since the heat effect of the cold cathode 17 of the body 11 can be reduced, it is possible to prevent the light guide body 11 from being discolored or deteriorated.

Further, as shown in FIG. 12, a fluorescent lamp
A rubber tube 25 or the like, which is a cylindrical heat interference material, may be attached to a portion around the 16 cold cathodes 17.

In this case, the heat conduction amount is reduced by the rubber tube 25 even if the cold cathode 17 becomes hot,
Since the amount of heat transferred from the fluorescent lamp 16 to the light guide 11 is reduced, it is possible to prevent the light guide 11 from being discolored or deteriorated.

Another embodiment will be described with reference to FIG.

In the embodiment shown in FIG. 13, a notch recess 11a for accommodating the fluorescent lamp 16 is formed on the rear surface side of the side of the light guide 11 where the fluorescent lamp 16 is attached, and this notch recess 11a is formed. The fluorescent lamp 16 is housed, the cover body 31 is attached from the back surface side, and the hook portion 31a formed at the tip of the cover body 31 is hooked on the front surface side of the light guide body 11. Further, a light shielding member 32 is attached to the front surface side of the cutout recess 11a so that the light from the fluorescent lamp 16 is directly guided to the light guide body 11.
To prevent irradiation to the front side of.

The light shielding member 32 is made of, for example, metal or resin, and has a mesh-shaped light shielding member as shown in FIG.
32a, or perforated light-shielding member as shown in FIG.
Anything such as 32b may be used.

As described above, the notch recess 11a is formed in the light guide body 11, and the fluorescent lamp 16 is housed in the notch recess 11a, so that the distance D1 of the cover body 31 protruding toward the front surface of the light guide body 11 is reduced. Since it can be made shorter than the conventional D2 shown in FIG. 14 and the light emitting area when viewed from the front surface side of the light guide 11 can be increased, the overall size can be reduced.

Further, for example, when a dot for diffusion is provided on the light guide 11, by adjusting the brightness of this dot and the brightness on the light shielding member 32, a wide and uniform light emitting region can be secured.

Further, instead of the reflection sheet 15 in the cover body 31, as shown in FIG. 17 or 18, the reflection surface 35 may be directly formed by plating or vapor deposition.

By directly forming the reflecting surface 35 in this way, a reflecting sheet such as a conventional silver sheet provided inside the cover body 31 is not required, so that the cost can be reduced and the cover body can be obtained. By making the inner surface of 31 smooth, it is possible to surely form the mirror-like reflecting surface 35 and improve the optical characteristics.

The frame 2 is not limited to the square shape but may be a box shape or a shallow dish shape.

Regarding the material of the lamp cover 19, A
Experiments were carried out using a BS resin, a mixed resin obtained by mixing a polycarbonate resin with an ABS resin, and a polycarbonate resin.
Resin is most suitable, and if ABS resin is used, high light reflectance can be optimally obtained. Therefore, in this case, since the conventional reflection sheet is not necessary, the number of parts can be reduced.

Further, since the fluorescent lamp 16 is brought into contact with the cutout recess 11a by the bent portion locking portion 10 provided in the cutout recess 11a of the light guide 11, conventionally, the lamp, the light guide, the reflection sheet,
A unit consisting of a lamp cover and a diffusion sheet and a frame for housing this unit were required, but it is possible to configure an optical unit with the lamp, the light guide, the lamp cover and the diffusion sheet. It can be handled as an independent member separately from the one having a function.

Further, since the cutout recess 11a is formed in the light guide body 11, even if the bent portion 16a of the fluorescent lamp 16 is fitted around the light guide body 11, the bent portion 16a of the lamp 16 will not be bent.
Since the fluorescent lamp 16 does not come into contact with the
It is possible to prevent it from coming into contact with 11 and being damaged.

Further, although the claw portion 12 serving as the locking portion is provided at a position corresponding to the cold cathode 17 of the fluorescent lamp 16, the case is not limited to the case where the claw portion 12 corresponds to the direct contact, and it corresponds to the vicinity of the periphery of the cold cathode 17. The same effect can be obtained in the case.

[0048]

According to the backlight of claim 1,
Since the light guide has a locking portion that locks the lamp, and the locking portion is provided at a position corresponding to the electrode of the lamp, even if the temperature around the electrode of the lamp rises, the light guiding member is locked. Since the temperature of the stop portion rises, but the temperature of the side surface does not rise significantly, it is possible to prevent discoloration and deterioration of the light guide body and reduce uneven brightness.

According to the backlight of the second aspect, in addition to the backlight of the first aspect, the lamp is bent in correspondence with the corners of the light guide body, and electrodes are formed near the respective ends. Since the locking part is formed on the adjacent sides of the light guide, the light from the lamp travels in the direction intersecting with the adjacent sides, so that even if the proximal end of the locking part is discolored or deteriorated. Even if occurs, the unevenness in brightness can be further reduced because the other part that is bent is more complementary.

According to the backlight described in claim 3, in the backlight according to claim 1, the bent portion of the L-shaped bent lamp is a notch formed at a corner portion of the rectangular light guide. The lamp can be easily attached by locking it at the bent part locking part of the concave part, and the surface of the lamp cover facing the lamp facing the lamp is coated with a metal film having a high light reflectance. Therefore, a separate reflection film or the like is not required and the configuration can be simplified, and the cost can be reduced by reducing the number of parts.

According to the backlight described in claim 4, the lamp is arranged so as to extend from the longitudinal direction of the side surface of the light guide,
Since the electrode is located outside the longitudinal end of the side surface of the light guide, the high temperature part around the electrode of the lamp corresponds to the part without the light guide, so that the high temperature part of the electrode is Since the light guide is hardly affected, discoloration and deterioration of the light guide can be prevented, and uneven brightness can be reduced.

According to the backlight of the fifth aspect, in addition to the backlight of the fourth aspect, the lamp is bent corresponding to the corner of the light guide, and electrodes are formed near the ends of the lamp. , Since the locking part is formed on the adjacent side of the light guide, the light from the lamp travels in the direction intersecting with the adjacent side, so that even if the base end of the locking part is discolored or deteriorated. Even if it occurs, since it is complemented by the other bent portion, it is possible to further reduce the uneven brightness.

According to the backlight described in claim 6, in addition to the backlight described in any one of claims 1 to 5, since the lamp covers the portion located around the electrode with a tubular body, the temperature of the electrode is tubular. Since it is transmitted to the light guide through the shaped body,
Since the temperature of the light guide can be reduced and the temperature of the light guide does not rise significantly, discoloration and deterioration of the light guide can be prevented, and uneven brightness can be reduced.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing an illumination device incorporating an embodiment of a backlight of the present invention.

FIG. 2 is a plan view of the same frame with the frame closed.

FIG. 3 is a side view of the same.

FIG. 4 is a plan view of the same frame with the frame opened.

FIG. 5 is a perspective view showing the vicinity of a claw portion of the same light guide body.

FIG. 6 is a side view showing a state in which the above fluorescent lamp is attached to a light guide by a lamp cover.

FIG. 7 is a perspective view showing a complementary relationship when the light guide body is deteriorated.

FIG. 8 is a side view showing a claw portion of a light guide according to another embodiment of the same.

FIG. 9 is a side view showing a claw portion of a light guide according to another embodiment of the present invention.

FIG. 10 is a side view showing a claw portion of a light guide according to still another embodiment of the same.

FIG. 11 is a front view showing an illumination device of another embodiment of the same.

FIG. 12 is a side view showing an illumination device in which a rubber tube is attached to a fluorescent lamp of another embodiment of the above.

FIG. 13 is a side view showing an illumination device of another embodiment of the same.

FIG. 14 is a side view showing a general lighting device.

FIG. 15 is a front view showing a light shielding member of an embodiment of the backlight of the present invention.

FIG. 16 is a front view showing a light blocking member of another embodiment of the same.

FIG. 17 is a side view showing an illumination device of another embodiment of the same.

FIG. 18 is a side view showing an illumination device according to another embodiment of the present invention.

[Explanation of symbols]

 10 Bent part Locked part 11 Light guide 11a Notched recessed part 12 Claw part as locked part 16 Fluorescent lamp 16a Bent part 17 Cold cathode as electrode 19 Lamp cover

Claims (6)

[Claims] 1. A backlight having a light guide body, which is disposed so as to face each other and has a locking portion for locking a lamp having an electrode, wherein the locking portion corresponds to an electrode of the lamp. A backlight that is provided in a position. 2. The light guide has a rectangular shape, the lamp is bent corresponding to a corner of the light guide, and electrodes are formed in the vicinity of respective ends of the lamp. The backlight according to claim 1, wherein the backlight is formed on adjacent sides of the light guide. 3. The light guide body has a rectangular shape, and has a cutout recess formed in at least one corner and a bent portion locking portion formed in the cutout recess. L with a length corresponding to each side of the body rectangle
A lamp cover having a bent portion that is bent in a letter shape and is locked to the bent portion locking portion corresponding to the cutout recess, and that is provided to face the lamp; The backlight according to claim 1, wherein a metal film having a high light reflectance is deposited on the surfaces facing each other. 4. A backlight having a light guide body, which is arranged opposite to a side surface and has a locking portion for locking a lamp having an electrode, wherein the lamp is extended from a longitudinal direction of a side surface of the light guide body. The backlight is characterized in that the electrodes are located outside the longitudinal ends of the side surfaces of the light guide. 5. The light guide has a rectangular shape, the lamp is bent corresponding to a corner of the light guide, and electrodes are formed in the vicinity of respective ends of the lamp. The backlight according to claim 4, wherein the backlight is formed on adjacent sides of the light body. 6. The backlight according to claim 1, wherein the lamp has a cylindrical body covering a portion located around the electrode.