JP4690563B2 - Light emitting diode - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a light emitting diode, and more particularly to a side light emitting type light emitting diode formed in a T shape.
[0002]
[Prior art]
Conventionally, in a liquid crystal display of a small electronic device typified by a mobile phone, a chip-type light emitting diode is used as a light source for a backlight. For example, as shown in FIG. 10, the chip-type light emitting diode 1 has a pair of electrodes 3 and 4 formed on the upper surface of a glass epoxy substrate 2 (hereinafter referred to as a glass-epoxy substrate) and is electrically conductive on one electrode 3. The light emitting diode element 6 is fixed using a bonding adhesive (not shown), and the upper electrode of the light emitting diode element 6 and the other electrode 4 are connected by a bonding wire 7, and the bonding wire 7 and the light emitting diode element are connected. 6 is sealed with a transparent resin body 8, and is a type that is surface-mounted on a printed wiring board (hereinafter referred to as PCB).
[0003]
When the chip-type light emitting diode 1 is used as a light source for a backlight of a liquid crystal display, the glass-epoxy substrate 2 is fixed to the upper surface of the PCB, and the light emitted from the light emitting diode element 6 is transmitted to the back surface side of the liquid crystal display plate. The light guide plate emits light by being introduced from the end of a light guide plate (not shown) provided, and the liquid crystal display plate is illuminated from the back side.
[0004]
[Problems to be solved by the invention]
However, when the chip-type light emitting diode 1 as described above is used as a light source for a large liquid crystal display screen, the brightness of the screen cannot be secured unless a plurality of light emitting diodes are mounted. A light source part will enlarge. Further, in the case where liquid crystals are displayed in multicolor using the above-described chip type light emitting diode 1, the chip type light emitting diodes 1 having different emission colors must be mounted, and the distance between adjacent chip type light emitting diodes 1 is also increased. Therefore, there is a problem that color unevenness is likely to occur when mixed color light emission is performed.
[0005]
Accordingly, an object of the present invention is to reduce the number of man-hours and reduce the number of light sources by using a light emitting diode as a light source for a large liquid crystal display screen so that sufficient brightness can be secured even with a small number of light emitting diodes. A light-emitting diode that achieves compactness, enables two-color light emission with a single light-emitting diode even when displaying liquid crystal in multiple colors, and provides a light-emitting diode that is less likely to cause color unevenness even when mixed-color light is emitted. It is.
[0006]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, a light-emitting diode according to claim 1 of the present invention is substantially T-shaped with a base portion provided with an external connection electrode and a main body portion rising from a substantially central portion of the base portion. The light emitting diode is formed and inserted from the back side into the hole formed in the printed wiring board, and the base part is mounted on the back electrode of the printed wiring board, and the external connection electrode is the base part Are provided independently on the front side and the back side of the main body, and on the front side and the back side of the main body, there are provided light-emitting parts that are electrically connected to the respective external connection electrodes. characterized in that it is protected respectively by a resin sealing body having a light-transmitting property.
[0007]
According to the present invention, since the light emitting diode is formed in a substantially T shape and the light emitting portion is provided on both the front side and the back side of the main body, the conventional light emitting diode is provided even when one light emitting diode is mounted. Is obtained. Therefore, the number of light emitting diodes mounted can be reduced, so that the number of man-hours can be reduced and the light emitting diodes can be made compact.
In addition, according to the present invention, since the external connection electrodes of the light emitting units on the front side and the back side are independent, only the light emitting unit on one side emits light, or the amount of power supplied to both light emitting units By changing, it is possible to change the mixed color emission.
[0008]
According to a second aspect of the present invention, in the light-emitting diode according to the first aspect, the light emitting portions provided on the front side and the back side of the main body are different in emission color.
[0009]
According to the present invention, by changing the light emission colors of the light emitting parts on the front side and the back side of the main body part, it is possible to emit two colors with one light emitting diode, and the distance between the light emitting parts is short, so mixed color light emission. Color unevenness is difficult to occur even when letting go.
[0012]
According to a third aspect of the present invention, in the light emitting diode according to the first aspect, a light shielding surface is formed on a part of the outer peripheral surface of the resin sealing body.
[0013]
According to this invention, the condensing property of the light emitted from the light emitting part can be improved by shielding a part of the outer peripheral surface of the resin sealing body.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of a light emitting diode according to the present invention will be described in detail with reference to the accompanying drawings. 1 to 5 show a first embodiment of a light emitting diode according to the present invention. FIG. 1 is an external view of the light emitting diode, FIG. 2 is a rear view of the light emitting diode, and FIG. 3 is a side view of the light emitting diode. 1 is a cross-sectional view taken along the line AA in FIG. 1, FIG. 4 is a perspective view showing a positional relationship when a light emitting diode is used as a light source for a backlight of a liquid crystal display, and FIG. 5 is a plan view thereof.
[0015]
As shown in FIGS. 1 to 3, a chip-type light emitting diode 11 according to this embodiment is made of a glass epoxy substrate, a BT resin (Bismaleimide Triazine Resin) substrate, or the like, and has base portions 12a and 12b extending in the left and right directions. And the main body portion 13 rising from the substantially central portion of the base portions 12a and 12b are formed in a substantially T-shape (used in a shape in which the T-shape is turned upside down). External connection electrodes 14a and 14b are formed on the front surfaces of the base portions 12a and 12b, and similar external connection electrodes 15a and 15b are formed on the back surfaces of the base portions 12a and 12b. Further, a cathode electrode 16a and an anode electrode 16b are formed at the center on the front side of the main body 13, and a similar cathode electrode 17a and anode electrode 17b are formed at the center on the back side. The cathode electrodes 16a, 17a and anode electrodes 16b, 17b are connected to the external connection electrodes 14a, 14b, 15a, 15b, respectively.
[0016]
The main body portion 13 has a vertically long rectangular parallelepiped shape, and a light emitting portion is formed on each of the front side and the back side. The light emitting section is constituted by light emitting diode elements 19a and 19b fixed to the upper surfaces of the cathode electrodes 16a and 17a. The upper surface electrodes of the light emitting diode elements 19a and 19b and the anode electrodes 16b and 17b are bonded to the bonding wires 20a. , 20b. Power is supplied from the external connection electrodes 14a, 14b, 15a, and 15b to the light emitting units 18a and 18b via the cathode electrodes 16a and 17a and the anode electrodes 16b and 17b, so that the light emitting diode elements 19a and 19b are in front. Light is emitted from the side and back side. In addition, when using said light emitting diode 11 for multicolor light emission, the light emitting diode elements 19a and 19b of different light emission color are used, and when using for single color light emission, the thing of the same light emission color is used for both.
[0017]
In the light emitting diode 11 according to this embodiment, the light emitting diode elements 19a and 19b and the bonding wires 20a and 20b are protected by the rectangular parallelepiped-shaped resin sealing bodies 21a and 21b protruding from the front side and the back side of the main body portion 13. Has been. An epoxy resin having translucency is used for the resin material of the resin sealing bodies 21a and 21b so as not to prevent light emission from the light emitting diode elements 19a and 19b.
[0018]
As shown in FIGS. 1 to 3, the light emitting diode 11 configured as described above has the main body 13 inserted into the circular hole 23 formed in the PCB 22 from the back side. Then, after the upper surfaces of the base portions 12a and 12b are brought into contact with the peripheral edge of the circular hole 23, the external connection electrodes 14a of the base portions 12a and 12b are connected to the back electrodes (not shown) printed on the back surface of the PCB 22. , 14b, 15a, and 15b are fixed with solder 24 so that electrical continuity with the PCB 22 is achieved. Cathode marks 25a and 25b indicating the polarity of the light emitting diode 11 are printed on the front side and the back side of the base portion 12a of the light emitting diode 11, respectively.
[0019]
Next, an embodiment in which the light emitting diode is used as a light source for a backlight of a liquid crystal display will be described with reference to FIGS. First, a V-shaped groove 31 is provided on the side end surface of the light guide plate 30 disposed on the front surface side of the PCB 22, and the main body 13 of the light emitting diode 11 is inserted into the V-shaped groove 31. When the light emitting diode 11 is fixed to the PCB 22, the direction of the base portions 12 a and 12 b is aligned with the direction orthogonal to the V shape of the V-shaped groove 31. By setting the light emitting diode 11 to such a position, light is emitted from the light emitting diode elements 19a and 19b of the main body 13 in opposite directions of the V-shaped groove 31. Most of the emitted light 33a and 33b is refracted to the front side of the light guide plate 30 when entering from the inclined surfaces 32a and 32b of the V-shaped groove 31, and is directly guided into the light guide plate 30 and proceeds straight.
[0020]
As described above, in this embodiment, it is possible to obtain the light emission luminance twice as high as that of the conventional light emitting device simply by mounting one light emitting diode 11. Therefore, when a large liquid crystal display screen emits monochromatic light, only one light emitting diode 11 is mounted. But enough brightness can be secured. Further, even in the case of multicolor light emission, if the light emitting diode elements 19a and 19b are configured with different light emission colors, it is only necessary to mount one light emitting diode 11, and the light emitting diode elements 19a and 19b are close to each other. For this reason, color unevenness hardly occurs when mixed color light is emitted, and a beautiful color can be obtained. In this embodiment, since the external connection electrodes 14a, 14b, 15a, 15b are provided separately on the front side and the back side of the main body 13, only one of the light emitting diode elements 19a, 19b emits light. It is also possible to change the amount of electric power applied to the respective light emitting diode elements 19a and 19b.
[0021]
In the embodiment shown in FIGS. 4 and 5, the case where one light emitting diode 11 is mounted has been described. However, two or three or more light emitting diodes 11 may be mounted as necessary. is there. In the above embodiment, the case where the light emitting diode 11 of the present invention is used as a light source for a backlight of a liquid crystal display has been described. However, it can be used as a light source for optical communication and various sensors, and also for various display devices. Of course.
[0022]
6 and 7 show a second embodiment of a light emitting diode according to the present invention. In the light emitting diode 11a according to this embodiment, the resin sealing bodies 21a and 21b projecting to the front side and the back side of the main body 13 shield light from part of the outer peripheral surface and emit light from the light emitting diode elements 19a and 19b. The light condensing property is improved. That is, the resin sealing bodies 21a and 21b are formed in a rectangular parallelepiped shape with a light-transmitting epoxy resin, but a light-shielding coating film is formed on the left and right side surfaces and the upper and lower surfaces of the resin sealing bodies 21a and 21b. The light shielding surfaces 26a and 26b are formed by applying plating or a light shielding sheet, and the light emitted from the light emitting diode elements 19a and 19b is emitted only from the light transmitting front surfaces 27a and 27b of the resin sealing bodies 21a and 21b. It is a thing. In addition, since it is the same as that of the structure of the previous light emitting diode 11 except the structure of the said resin sealing bodies 21a and 21b, detailed description is abbreviate | omitted by attaching | subjecting the same code | symbol.
[0023]
FIG. 7 shows an embodiment in which the light emitting diode 11a is used as a light source for a backlight of a liquid crystal display. In this case, the lights 33a and 33b emitted from the light emitting diode elements 19a and 19b are blocked by the light shielding surfaces 26a and 26b of the resin sealing bodies 21a and 21b, so that they do not diffuse around the resin sealing bodies 21a and 21b. Light is emitted only from the translucent front surfaces 27a and 27b. This results in enhancing the light condensing properties of the light 33 a and 33 b, and since the region incident on the inclined surfaces 32 a and 32 b of the V-shaped groove 31 becomes narrow, strong light is guided into the light guide plate 30. Since the positional relationship between the light emitting diode 11a and the light guide plate 30 is the same as that of the previous embodiment shown in FIG. 5, detailed description is omitted by attaching the same reference numerals.
[0024]
8 and 9 show a third embodiment of the light emitting diode according to the present invention. Similarly to the previous embodiment, the light emitting diode 11b according to this embodiment also shields a part of the outer peripheral surface of the resin sealing bodies 21a and 21b protruding from the front side and the back side of the main body 13, and the light emitting diode element 19a. , 19b to improve the light condensing property of the light emitted. That is, the resin sealing bodies 21a and 21b are formed in a rectangular parallelepiped shape with a translucent epoxy resin. In this embodiment, the resin sealing bodies 21a and 21b are formed on one side surface, upper and lower surfaces, and the front surface of the resin sealing bodies 21a and 21b. The light shielding surfaces 26a and 26b are formed by applying a light shielding coating film, plating or a light shielding sheet, and light emitted from the light emitting diode elements 19a and 19b is transmitted through the other light transmitting side surfaces 28a and 21b of the resin sealing bodies 21a and 21b. It is configured to emit light only from 28b. In addition, since it is the same as that of the structure of the previous light emitting diode 11 except the structure of the said resin sealing bodies 21a and 21b, detailed description is abbreviate | omitted by attaching | subjecting the same code | symbol.
[0025]
FIG. 9 shows an embodiment in which the light emitting diode 11a is used as a light source for a backlight of a liquid crystal display. In this case, the light 33a and 33b emitted from the light emitting diode elements 19a and 19b are blocked by the light shielding surfaces 26a and 26b of the resin sealing bodies 21a and 21b, so that they do not diffuse to the surroundings, and each inclination of the V-shaped groove 31 Light is emitted only from the light transmitting side surfaces 28a and 28b of the resin sealing bodies 21a and 21b facing the surfaces 32a and 32b. This enhances the light-collecting properties of the light 33a and 33b and also results in the light 33a and 33b guided into the light guide plate 30 approaching each other, changing the light emission color of the light-emitting diode elements 19a and 19b to emit two colors. In this case, the mixing of the two colors in the light guide plate 30 is made even smoother. Note that the positional relationship between the light emitting diode 11b and the light guide plate 30 is the same as that of the previous embodiment shown in FIG.
[0026]
【The invention's effect】
As described above, according to the light emitting diode according to the present invention, the light emitting diode is formed in a substantially T shape, so that the light emitting portion can be provided on both the front side and the back side of the main body. Luminance of two light emitting diodes can be obtained. For this reason, for example, when used as a light source for a backlight of a liquid crystal display, the brightness of a large liquid crystal display screen can be sufficiently ensured even if the number of mounted light emitting diodes is small. The number of light-emitting diode mounting steps can be reduced, and the light source portion can be made compact.
[0027]
In addition, according to the light emitting diode of the present invention, multicolor light emission is possible only by changing the light emission colors of the light emitting parts provided on the front side and the back side of the main body part, and the distance between the light emitting parts is also close, so that color mixing is possible. Even when light is emitted, color unevenness is less likely to occur and quality can be improved.
[0028]
Furthermore, according to the light emitting diode according to the present invention, since the light shielding surface is formed on a part of the outer peripheral surface of the resin sealing body, the light condensing property of the light emitted from the light emitting portion is improved, and a specific location is determined. Can be effectively irradiated.
[Brief description of the drawings]
FIG. 1 is an external view of a light emitting diode according to a first embodiment of the present invention.
FIG. 2 is a rear view of the light emitting diode.
3 is a cross-sectional view taken along line AA of FIG. 1 showing a side surface side of the light emitting diode.
FIG. 4 is a perspective view showing an arrangement relationship when the light emitting diode is used as a light source for a backlight of a liquid crystal display.
FIG. 5 is a plan view of FIG. 4;
FIG. 6 is an external view of a light emitting diode according to a second embodiment of the present invention.
FIG. 7 is a plan view showing an arrangement relationship when the light-emitting diode is used as a light source for a backlight of a liquid crystal display.
FIG. 8 is an external view of a light emitting diode according to a third embodiment of the present invention.
FIG. 9 is a plan view showing an arrangement relationship when the light emitting diode is used as a light source for a backlight of a liquid crystal display.
FIG. 10 is a perspective view showing an example of a conventional light emitting diode.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 Light emitting diode 12a, 12b Base part 13 Main-body part 14a, 14b External connection electrode 15a, 15b External connection electrode 19a, 19b Light emitting diode element (light emission part)
21a, 21b Resin sealing body

Claims (3)

A base part provided with an external connection electrode and a main body part rising from a substantially central part of the base part are formed in a substantially T shape, and the main body part is inserted from the back side into a hole formed in a printed wiring board. The base part is a light emitting diode mounted on the back electrode of the printed wiring board,
The external connection electrodes are provided independently on the front side and the back side of the base part, respectively, and light emitting parts that are electrically connected to the external connection electrodes are respectively provided on the front side and the back side of the main body part. provided, light emitting diodes each emitting unit is characterized in that it is protected respectively by a resin sealing body having a light transmitting property.   The light emitting diode according to claim 1, wherein the light emitting parts provided on the front side and the back side of the main body part have different emission colors.   The light-emitting diode according to claim 1, wherein a light shielding surface is formed on a part of the outer peripheral surface of the resin sealing body.

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