JPH1022528A - Led back light - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize compactness, thinning and high luminance and readily correspond also to change of a light emission area, a shape, etc., by forming an electrode part for electrical connection to a wiring part at both ends in a wiring part longitudinal direction of a chip part type LED. SOLUTION: In an LED back light 1, a chip part type LED 3 is fixed to be fit to a side surface of a light guiding board 2. Screwed overhanging parts 7a, 7b for fixing by a screw 6 are provided to a side surface part of the LED back light 1 for fixing and electrically connection between the LED back light 1 and a wiring board 5. An LED back light having such a structure can corresponds to fixing even if the light guiding board 2 is thin or small and can also corresponds to even a back light of a complicated shape since it has a structure for fitting a very compact and single chip part type LED 3 to a side surface part of the light guiding board 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an LE using a light emitting diode, for example, used for a liquid crystal display of a portable device.
Related to D backlight.

[0002]

2. Description of the Related Art A conventional backlight for a liquid crystal display device will be described with reference to FIGS. FIG. 7 (a)
And (b) are light emitting diodes (hereinafter, LED), respectively.
Top view and side view of the backlight using
FIG. 8 is an enlarged perspective view of the LED used in FIG.

A conventional LED backlight has a structure in which an LED portion 102 is fitted into a concave portion 101 provided on a side surface of a light guide plate 100 as shown in FIG. Here, as shown in FIG. 8, the LED section 102 includes an LED chip 1 inside an envelope 103 in which the reflection section and the wiring section are integrated.
04, and a resin 1 such as epoxy
05. 106 is a lead frame.

[0004] In this structure, light emitted from the LED sections 102 arranged on both opposing sides of the light guide plate 100 is guided to the light guide plate 100, and the light guide plate 100 emits light over the entire surface. The function of a backlight such as a liquid crystal display element to be arranged is provided.

FIGS. 9 and 10 show another conventional LED.
FIG. 2 is a perspective view of a backlight and an enlarged perspective view of an LED used in the LED backlight. This conventional example is shown in FIG.
As shown in FIG. 7, the LED section 108 is fitted into the fitting section 107 provided near the side surface of the light guide plate 100. Here, the LED unit 108 is provided on the printed circuit board 110 on which the wiring pattern 109 is formed.
The chip 104 is mounted, and the LED chip 104 is protected by a coating resin 111 such as silicon.

Also in this structure, light emitted from the LED unit 108 is guided to the light guide plate 100, and the light guide plate 1
00 becomes the backlight.

FIG. 11 is a perspective view of another conventional LED backlight. In this conventional example, as shown in FIG. 11, an LED chip 104 is mounted in a reflector 112, and the upper portion thereof is sealed with a resin 113 such as an epoxy resin. Reference numeral 114 denotes a lead frame, and the lead frame 114 and the reflector 112 are integrally formed by an insert molding method or the like.

In this structure, the light guide plate 100 as shown in FIGS. 7 to 10 is not provided, and light is emitted from the entire surface of the reflector 112.

[0009]

By the way, in the structure shown in FIG. 7, the light guide plate portion and the LED portion are separated from each other, so that the LED portion can be standardized to some extent, and light emitting areas having different sizes can be obtained. The backlight can be dealt with by changing only the light guide plate parts.

On the other hand, when the number of chips is to be changed, it is necessary to change the envelope itself in which the chip is built, and it takes time and effort to change the design. In addition, if the light emitting area is large, it is naturally difficult to achieve uniform light emission. However, if the light emitting area is to be solved, it is not easy to cope with it, for example, the number of envelopes requiring a large space needs to be increased. .

In addition, the structures shown in FIGS. 7 to 10 do not have a structure in which a light reflector is present on the side surface of the light guide plate 100. Therefore, there is a problem in that light leaks from the side surface to cause loss of light.

Further, when viewed individually, in the structure of FIG.
Since the ED section 108 has a structure to be fitted into the light guide plate 100, it needs to be made quite small, and there is a problem that the manufacturing process is complicated and the product cost increases.
Further, if any one of a plurality of chips has a defect, the entire LED section 108 must be replaced, and the yield of the LED section greatly affects the product unit price.

Further, in the structure shown in FIG. 11, if the light emitting area changes, both the lead frame and the molding die need to be changed.
Further, in order to emit light uniformly, a certain thickness is required, and it is difficult to reduce the thickness.

It is an object of the present invention to provide an LED backlight which can be made smaller, thinner and brighter than before, and can easily cope with changes in the light emitting area, shape and the like. It is in.

[0015]

According to a first aspect of the present invention, there is provided an LED backlight having a flat light guide plate and a fitting portion provided on a side surface of the light guide plate. Having a chip part type LED to be combined, and forming a wiring part on the entire surface other than the fitting part of the side part of the light guide plate, and forming the wiring part at both ends in the wiring part longitudinal direction of the chip part type LED, It is characterized in that an electrode portion for making an electrical connection with the wiring portion is formed.

[0016] The LED backlight according to claim 2 is
The fitting part according to claim 1 has a stepped structure that extends outward from the side surface of the light guide plate so that the chip component type LED is fitted substantially perpendicularly from the side surface direction of the light guide plate.

The LED backlight according to claim 3 is
The fitting part according to claim 2, wherein the chip part type LE is provided.
The entire outer periphery including the electrode portion of D is configured to fit within the side surface of the light guide plate.

The LED backlight according to claim 4 is
The fitting part according to claim 2, wherein the chip part type LE is provided.
It has a tunnel-like structure so that D is fitted from the upper surface direction of the plane portion of the light guide plate.

The LED backlight according to claim 5 is
The LED backlight according to any one of claims 1 to 4, wherein a projecting portion for performing electrical connection with the outside and mechanically fixing is formed integrally with a wiring portion on a side surface portion of the light guide plate. It is characterized by becoming.

[0020] The LED backlight according to claim 6 is
According to a fifth aspect of the present invention, in the LED backlight according to the fifth aspect, the protruding portion is a screwing overhang that can be screwed, and a lower surface thereof is flush with a lower surface of the light guide plate.

Hereinafter, the operation of each claim will be described.

According to the first aspect of the present invention, since the structure is such that the LED of a very small size and a single chip component is fitted to the side surface of the light guide plate, the light guide plate is thin. Not only is possible, but also a backlight having a complicated shape can be handled.

Further, since the space required for the LED section is not required as much as the conventional case, it can contribute to downsizing. Alternatively, if the same amount of space is used, for example, the LED units can be arranged on all four sides of the outer periphery of the light guide plate, and high luminance can be achieved.

Also, LEDs having different emission colors can be mounted. Further, since the chip component type LEDs have the same brightness and electrical characteristics, an LED backlight with a high yield can be realized.

Further, since the wiring portion is formed on the entire surface of the light guide plate other than the fitting portion on the side surface portion, it is possible to eliminate the light leaking from the side surface of the light guide plate to the outside, so that the wiring portion can be made higher than before. Brightness can be improved.

Further, the structure in which the wiring portion is formed on the side surface portion of the light guide plate allows the electrodes to be directly taken out of the backlight main body, eliminating the need for a conventional lead frame or the like and contributing to downsizing. it can.

In addition, it is only necessary to adopt a structure in which a single chip component type LED is appropriately mounted on the side surface as needed, even if the design is changed, such as enlarging the light emitting area of the light guide plate. it can.

According to the second aspect, since the LED chip only needs to be brought into contact with the step on the side surface of the light guide plate as it is, the mounting is easy.

According to the third aspect, since the entire outer periphery including the electrode portion of the chip component type LED is configured to be accommodated in the side surface portion of the light guide plate, fitting of the LED is easier, and furthermore, the light emitting portion of the LED. All of the light from the light-emitting portion is effectively guided to the light guide plate without leaking from the side surface direction (vertical direction) of the light-emitting portion, so that it is possible to contribute to an improvement in luminous efficiency.

According to the fourth aspect, the fitting portion on the side surface of the light guide plate has a tunnel-like structure such that the chip component type LED is fitted from the upper surface direction of the light guide plate.
After the fitting of D, temporary fixing or the like is unnecessary until soldering or the like is performed.

According to the fifth aspect, the wiring portion on the side surface portion of the light guide plate is formed with a projection for performing electrical connection with the outside and mechanically fixing the light guide plate. The LED backlight can be easily installed at the same time as being installed on a substrate or the like, and an LED backlight that is very easy to assemble can be provided.

According to the sixth aspect of the present invention, the projecting portion is a screwing overhanging portion that can be screwed, and the lower surface thereof is flush with the lower surface of the light guide plate. Moreover, reliable electrical connection can be made.

[0033]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows an LE according to this embodiment.
FIG. 2 is a perspective view showing a use state of the D backlight, and FIG. 2 is a top view of the LED backlight of the present embodiment.

As shown in FIG. 1, the LED backlight 1 of the present embodiment has a chip-type LED on the side of a light guide plate 2.
3 (hereinafter simply referred to as LED3). In this case, two LEDs 3 are mounted on each of the opposing side surfaces, for a total of four LEDs. In addition, the wiring portion 4 is formed on the entire surface of the side surface of the light guide plate 2 where there is no LED 3. The LED 3 is fixed by the solder 4a. The LED backlight 1 is mounted on an external wiring board 5.

Further, the LED backlight 1 and the wiring board 5
In order to secure and electrically connect the LED backlight 1 to the LED backlight 1, screw fastening projections 7 a and 7 b for fixing with the screws 6 are provided on the side surface of the LED backlight 1. The lower surfaces of the screw fastening projections 7a and 7b and the lower surface of the light guide plate 2 are flush. In the figure, 8 is the LED backlight 1
LCD panel illuminated by

In the above structure, a light transmitting resin such as polycarbonate or acrylic is used as a material of the light guide plate 2. As a structure of the wiring portion 4, first, an ABS resin whose surface can be plated is used as a material of the wiring portion 4. Then, the ABS resin and the light guide plate are integrally formed by two-color molding. Thereafter, the ABS resin portion is plated to complete the wiring portion 4.

Further, as another structure of the wiring section 4, the wiring section 4 can be formed of a metal frame. In this case, a metal frame is placed in a mold in advance, and a light guide plate material is poured into the metal frame and molded integrally, that is, it is manufactured by so-called insert molding.

The electrical equivalent circuit of the above structure is shown in FIG.
, Two L's from each side surface of the light guide plate 2
There is ED light emission. As described above, the wiring section 4 naturally functions to electrically connect the LEDs, but further has the following features. That is, by forming the wiring on the entire side surface of the light guide plate 2 as described above, it functions to reflect light traveling in the lateral direction (outward) from the side surface of the light guide plate 2 inward without leaking to the outside. by this,
High brightness can be achieved.

The fitting of the LED 3 and the light guide plate 2 is performed, for example, in a structure as shown in a partially enlarged view of FIG. As shown in FIG. 4, the light emitting portion 9 of the LED 3 has a fitting portion 1 having a stepped portion provided on the side surface of the light guide plate 2 and extending to the outside.
It has a structure that can be fitted into the zero. 11 is LE
D3 is an electrode portion formed in the longitudinal direction so as to be connected to the wiring portion 4.

With the LED backlight having the above structure, a very small and single chip component type LE
Since D3 is configured to be fitted to the side surface of the light guide plate 2,
Even if the light guide plate 2 is thin or small, not only can it be mounted, but also a backlight having a complicated shape can be supported. Regarding the thickness of the light guide plate 2, it can be implemented relatively easily even if the size is 1 mm or less.

Further, since the space required for the LED 3 is not required as much as the conventional case, it can contribute to downsizing. Alternatively, if the same space is used, for example, the LEDs 3 can be arranged on the four outer peripheral sides of the light guide plate 2, and high luminance can be achieved. Further, LEDs having different emission colors can be mounted. Further, since the chip component type LEDs 3 have uniform brightness and electrical characteristics, an LED backlight with a high yield can be realized.

Further, as described above, since the wiring portion 4 is formed on the entire surface other than the fitting portion 10 on which the LED 3 is mounted on the side surface of the light guide plate 2, the wiring portion 4 extends from the side surface of the light guide plate 2 to the outside. Light that leaks to the light source can be eliminated, and higher brightness than before can be achieved. At the same time, since the wiring portion 4 is formed on the side surface of the light guide plate 2, the electrodes can be directly taken out from the main body of the backlight 1, and a conventional lead frame or the like is not required, thereby contributing to downsizing.

In addition, even if the light emitting area of the light guide plate is enlarged or the shape thereof is changed, it is only necessary to appropriately attach the LED 3 to the side surface of the light guide plate 2 if necessary. , Can be easily handled.

By the way, in the structure shown in FIG. 4, the side surface of the backlight (light guide plate) is perpendicular to the uniform light emitting surface. However, this side surface is inclined, for example, at 45 degrees so as to face upward. If LED3 is arranged at
The light emitted from the LED 3 is directed to the lower surface of the light guide plate, and the light reflected on the lower surface is effectively emitted from the upper surface, so that the luminous efficiency can be improved. In addition, with this structure, in the structure of FIG. 4, there was light that escaped from above the light emitting portion 9 of the LED 3, but this light can also be effectively guided inside the light guide plate. Furthermore, by making the end face beveled, the area is expanded compared to the vertical case,
The LEDs 3 can be arranged with a margin. Alternatively, even if the thickness of the light guide plate 2 is made thinner than the structure of FIG. 4, the LED 3 can be attached, which further contributes to the thinning of the backlight.

FIG. 5 shows a modification of the fitting structure of the LED 3 and the light guide plate 2 shown in FIG. This structure has a tunnel-like structure such that the fitting portion 11 on the side surface portion of the light guide plate 2 fits the LED 3 from the upper surface direction of the flat portion of the light guide plate 2. No temporary fixing is required until soldering or the like is performed.

FIGS. 6A and 6B show an LED, respectively.
It is the perspective view and its partial perspective view which show the further another example of the fitting structure of 3 and the light-guide plate 2. FIG. In this structure, the LED
Since the entire outer periphery including the electrode portion 11 of the LED 3 is configured to fit within the side surface of the light guide plate 2, the fitting of the LED 3 is easier, and the light from the light emitting portion 9 of the LED 3 is applied to the side surface of the light emitting portion 9. Since all light is effectively guided to the light guide plate 2 without leaking from the direction (vertical direction), the luminous efficiency can be further improved.

[0047]

As described above, according to the present invention,
Since the structure is such that the LED chip is fitted on the side surface of the light guide plate, it can be made smaller and thinner than before. Further, it is possible to easily cope with a change in the light emitting area, shape, and the like of the light guide plate.

Further, since the wiring is provided on the entire side surface of the light guide plate except for the portion where the LED chip is attached, light traveling outward from the side surface of the light guide plate can be reflected inward, and high luminance can be achieved. Moreover, with the same structure, directly from the backlight body,
Since the electrode can be taken out, the conventional L
A lead frame or the like for the ED is not required, which can contribute to downsizing.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a use state of an LED backlight according to an embodiment of the present invention.

FIG. 2 is a top view of an LED backlight according to an embodiment of the present invention.

FIG. 3 is an equivalent circuit diagram showing an electrical connection state of LEDs of the LED backlight of FIG. 1;

FIG. 4 is a partially enlarged perspective view showing a fitted state of an LED and a light guide plate according to an embodiment of the present invention.

FIG. 5 is a partially enlarged perspective view showing a fitted state of an LED and a light guide plate according to another embodiment of the present invention.

FIGS. 6A and 6B are a partially enlarged perspective view and a partial perspective view showing a fitting state of an LED and a light guide plate according to still another embodiment of the present invention, respectively.

FIGS. 7 (a) and (b) each show L according to a conventional example.
3A and 3B are a top view and a side view of an ED backlight.

FIG. 8 shows an LED used in the LED backlight of FIG. 7;
FIG.

9A and 9B are a top view and a side view, respectively, of another conventional LED backlight.

FIG. 10 shows an LE used for the LED backlight of FIG. 9;
The perspective view of the D section.

FIG. 11 is a perspective view of another conventional LED backlight.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 LED backlight 2 Light guide plate 3 Chip component type LED 4 Wiring part 7a, 7b protrusion part of light guide plate 10 Fitting part 11 Electrode part

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[Procedure amendment]

[Submission date] August 27, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Brief description of drawings

[Correction method] Change

[Correction contents]

[Brief description of the drawings]

FIG. 1 is a perspective view showing a use state of an LED backlight according to an embodiment of the present invention.

FIG. 2 is a top view of an LED backlight according to an embodiment of the present invention.

FIG. 3 is an equivalent circuit diagram showing an electrical connection state of LEDs of the LED backlight of FIG. 1;

FIG. 4 is a partially enlarged perspective view showing a fitted state of an LED and a light guide plate according to an embodiment of the present invention.

FIG. 5 is a partially enlarged perspective view showing a fitted state of an LED and a light guide plate according to another embodiment of the present invention.

FIGS. 6A and 6B are a partially enlarged perspective view and a partial perspective view showing a fitting state of an LED and a light guide plate according to still another embodiment of the present invention, respectively.

FIGS. 7 (a) and (b) each show L according to a conventional example.
3A and 3B are a top view and a side view of an ED backlight.

FIG. 8 shows an LED used in the LED backlight of FIG. 7;
FIG.

FIG. 9 is a perspective view of another conventional LED backlight.
FIG .

FIG. 10 shows an LE used for the LED backlight of FIG. 9;
The perspective view of the D section.

FIG. 11 is a perspective view of another conventional LED backlight.

[Description of Signs] 1 LED backlight 2 Light guide plate 3 Chip component type LED 4 Wiring portion on side surface of light guide plate 7a, 7b Projection portion 10 Fitting portion 11 Electrode portion

Claims (6)

[Claims] 1. A light guide plate having a flat shape, and a chip component type LED fitted to a fitting portion provided on a side surface portion of the light guide plate, wherein the fitting portion on a side surface portion of the light guide plate is provided. An LED backlight formed by forming a wiring portion on the entire surface other than the above, and forming electrode portions for electrically connecting to the wiring portion at both ends in the longitudinal direction of the wiring portion of the chip component type LED. . 2. The LED backlight according to claim 1, wherein the fitting portion fits the chip component type LED substantially perpendicularly from a side surface direction of the light guide plate. An LED backlight characterized by having a stepped structure that spreads out. 3. The LED backlight according to claim 2, wherein the fitting portion is configured such that the entire outer periphery including the electrode portion of the chip-type LED fits in the side surface portion of the light guide plate. LED backlight. 4. The LED backlight according to claim 1, wherein the fitting portion has a tunnel-like structure such that the chip component type LED is fitted from a top surface direction of a plane portion of the light guide plate. LED backlight characterized by the above. 5. The LE according to claim 1, wherein
In the D-backlight, an LED back is formed by integrally forming, on a wiring portion on a side surface portion of the light guide plate, a protruding portion for making an electrical connection with the outside and performing a mechanical fixing. Light. 6. The LED backlight according to claim 5, wherein the protruding portion is a screwing overhang that can be screwed, and a lower surface thereof is flush with a lower surface of the light guide plate. LED backlight to do.