JPH0736459U - Light emitting diode - Google Patents

Abstract

(57) [Abstract] [Purpose] The light emitted from the semiconductor chip is effectively focused in the optical axis direction without changing the size of the light emitting point, the size of the bottom plate of the saucer, and the size of the opening end of the reflection wall. It is possible to increase the amount of light in the optical axis direction. [Structure] The reflecting wall 9B of the tray 9 is bent outward to form first to third reflecting surface portions 20A to 20C.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a mold type light emitting diode used for a vehicle lamp, a lighting device, a display device, and the like.

[0002]

[Prior art]

 Conventionally, in vehicular lamps and lighting devices such as tail lights, turn signals, stop lights, backward lights, and high-mount stop lamps, they have a longer life than ordinary incandescent light bulbs and generate significantly less heat and power. A large number of light-emitting diodes (hereinafter abbreviated as LEDs) are mounted on a board because they have many advantages such as high luminous efficiency, thinner lighting fixtures, and easier mounting on the vehicle body. Have been proposed (eg, Japanese Utility Model Publication No. 4-24562, Japanese Utility Model Publication No. 62-32560, etc.).

3 to 5 are a sectional view of a main part of an illumination device using such an LED as a light source, a diagram showing optical paths of direct light and reflected light of a LED, and a sectional view of a saucer. In these figures, 1 is a transparent front lens, 2 is a front surface side of which a diffusion lens 3 made up of a number of small convex lenses is formed, and back side thereof is formed of a plurality of condenser lenses 5 corresponding to the respective LEDs 4. It is an inner lens. The LED 4 is a semiconductor chip 6 made of gallium phosphide (GaP), gallium aluminum phosphide (GaAlP), gallium arsenide phosphide (GaAsP), etc., a pair of lead wires 7a and 7b, a gold wire 8, a receiving plate 9 and these are molded. , And an envelope 10 that protects from the outside air. The envelope 10 is formed of a transparent resin such as an epoxy resin into a columnar shape, and the emission side end face forms an aspherical (elliptical) dome portion 10A to enhance directivity of light emission output. The semiconductor chip 6 is arranged together with the tray 9 on the side opposite to the dome portion 10A side from the center O of 10A, that is, on the side opposite to the dome portion, and is connected to one lead wire 7a via a gold wire 8. The saucer 9 is formed in a dish shape with aluminum foil or the like, so that the saucer 9 has a circular bottom plate 9A as shown in FIG. 5, and a projection wall inclined outward by a required angle (α) and surrounding the entire circumference of the bottom plate 9A. 9B, the entire inner surface forms a reflection surface, and is connected and fixed to the tip of the other lead wire 7b. Therefore, the open end diameter D of the tray 9 is sufficiently larger than the diameter D1 of the bottom plate 9A. The semiconductor chip 6 is arranged at the center of the inner surface of the bottom plate 9A, and is electrically connected to the tray 9 by the silver paste 12.

In such a configuration, the light 15 emitted from the semiconductor chip 6 has a half-value angle of about 30 °, is refracted and condensed in the optical axis direction by the dome portion 10 A, and is condensed by the condenser lens 5 of the inner lens 2. When the light is further refracted in the optical axis direction, it becomes parallel light that is substantially parallel to the optical axis, is diffused into a desired light distribution pattern by the diffusion lens 3, and then is transmitted through the front lens 1. In FIG. 4, reference numeral 15a indicates direct light emitted from the semiconductor chip 6, and 15b indicates reflected light emitted from the semiconductor chip 6 and reflected by the reflection wall 9B of the tray 9. When the dome portion 10A is formed into a spheroidal dome, the angle of incidence on the boundary surface exceeds the critical angle in the vicinity of the base portion 110a of the dome portion and internal reflection occurs, which is not preferable.

[0005]

[Problems to be solved by the device]

 By the way, in the above-described conventional LED 4, the light 15b 'having a large reflection angle (critical angle) among the reflected light 15b reflected by the reflection wall 9B of the tray 9 is transmitted through the vicinity 110a of the base of the dome portion 10A. However, since the light 15b ′ that passes through the vicinity 110a of the base portion goes to the outside, it is lost outside the effective irradiation range, and it is difficult for the condenser lens 5 of the inner lens 2 to control this light 15b ′. Therefore, there is a problem in effective use of light.

Therefore, as a method of solving such a problem, the light emitting point of the LED is shifted to the side opposite to the dome portion along the optical axis, and the inclination angle α of the reflecting wall 9B of the tray 9 is not changed and the bottom plate 9A is not changed. It is conceivable to reduce the diameter D1. However, in the method of shifting the light emitting point of to the side opposite to the dome portion along the optical axis, the R shape of the dome portion and the step of the inner lens 2 are designed according to the light collecting point of the reflection wall 9B of the LED 4. If the light collection point is shifted and the distance L from the top 110b of the dome portion 10A to the semiconductor chip 6 is further increased, the inner lens 2 cannot collect and diffuse so as to have a desired light distribution pattern. On the other hand, the method of reducing the diameter D1 of the bottom plate 9A of the tray 9 without changing the inclination angle α of the reflection wall 9 makes it difficult to mount the semiconductor chip 6 at a predetermined position on the bottom plate 9A, and If the gaps occur, the gap with the reflection wall 9B becomes partially narrow, so that when the paste 12 is joined by the silver paste 12, a part of the paste 12 rises and adheres to the reflection wall 9B to reduce the reflection area, or the semiconductor. A new problem arises in that it adheres to the surface of the chip 6 and short-circuits with the gold wire 8. In addition to this, it is conceivable to increase the diameter D1 of the bottom plate 9A to increase the inclination angle α of the reflection wall 9B. In that case, a part of the reflected light 15b reflected by the reflection wall 9B is partially removed. Since it comes into contact with the bottom plate 9A and is reflected, light loss is caused.

Therefore, the present invention has been made in view of the above-mentioned conventional problems, and the purpose thereof is to provide a light emitting point, a size of a bottom plate of a saucer, and a size of an opening end of a reflection wall. It is an object of the present invention to provide a light emitting diode capable of effectively condensing light emitted from a semiconductor chip in the optical axis direction without changing the above, and increasing the amount of light in the optical axis direction.

[0008]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the present invention has a plate-shaped saucer and a bottom which surround the circumference of the bottom board and the reflection wall whose open end side is larger than the bottom board and which forms a reflection surface. The semiconductor chip placed on the face plate is separated by a predetermined distance from the center of the dome portion to the side opposite to the dome portion in an envelope in which the emitting end face forms the dome portion, which is formed of a transparent resin in a cylindrical shape. In the light emitting diode formed by molding, the reflecting wall of the tray has a plurality of reflecting surface portions having different inclination angles with respect to the optical axis by being bent so as to be convex outward.

[0009]

[Action]

 In the present invention, the reflecting wall of the tray has a plurality of reflecting surface portions having different inclination angles with respect to the optical axis by being bent so as to be convex outward. Since the angle of inclination of these reflection surface portions is larger than the inclination angle α of the conventional reflection wall, the light emitted from the semiconductor chip is further reflected toward the optical axis side, and the reflected light traveling outward is reduced.

[0010]

【Example】

 Hereinafter, the present invention will be described in detail with reference to the embodiments shown in the drawings. FIG. 1 is a view showing a light emitting diode according to the present invention and an optical path of reflected light, and FIG. 2 is a sectional view of a saucer. In the figure, the same components as those in FIGS. 3 to 5 are designated by the same reference numerals and the description thereof will be omitted. The present invention does not change the position of the tray 9 itself, in other words, does not change the light emitting point of the LED, and does not change the size of the bottom plate 9A of the tray 9 and the size of the opening end of the reflection wall 9B. By bending the reflection wall 9B so as to be convex outward, the inner surface of the reflection wall 9B is configured by the first to third reflection surface portions 20A to 20C having different inclination angles with respect to the optical axis. Other configurations are the same as the conventional ones.

The diameter D1 of the bottom plate 9A is 0.6 mmφ, the height H and the opening diameter D of the reflection wall 9B are 0.87 mm and 1.38 mmφ, respectively, which are the same as those of the conventional tray shown in FIG. is there. The first reflection surface portion 20A is provided on the bottom plate 9A side, the inclination angle β1 thereof is 48 °, the second reflection surface portion 20B is provided adjacent to the first reflection surface portion 20A, and the inclination angle β2 thereof is set. Is 62 °, the third reflecting surface portion 20C is provided adjacent to the second reflecting surface portion 20B, and the inclination angle β3 thereof is 75 °. The inclination angles β1 to β3 of the first to third reflection surface portions 20A to 20C are larger than the inclination angle α of the straight reflection wall 9B of the tray 9 in the conventional LED shown in FIG. Since 9 is bent so as to be convex outward, both are large.

In the LED 4 having such a saucer 9, the reflected light 15 b reflected by the first to third reflecting surface portions 20 A to 20 C of the reflecting wall 9 B among the light 15 emitted from the semiconductor chip 6 is as described above. As described above, since the tilt angles β1 to β3 of the first to third reflecting surface portions 20A to 20C are larger than the tilt angle α of the straight reflecting wall 9B of the tray 9 in the conventional LED, reflection on the optical axis side, It is condensed and becomes a parallel light ray by the optical axis. Therefore, it is possible to reduce the reflected light transmitted through the vicinity 110a of the base of the dome portion 10A. Further, even if the reflecting wall 9 is bent, the opening diameter is the same as that of the conventional one, so that the direct light 15a is not affected at all. Therefore, compared with the conventional LED, the light amount in the optical axis direction is increased, and the irradiation efficiency can be improved.

In addition, since the present invention does not change the light emitting point of the LED, the size of the bottom plate 9A of the tray 9 and the opening end diameter of the reflection wall 9B, it is the same as before, so that the lens design may be changed or the semiconductor chip may be changed. There is no troublesome work of attaching 6 to the tray 9, and the reflection area of the reflection wall 9B is not reduced by the silver paste 12.

Although the above embodiment has been described with respect to the case where the three reflecting surface portions 20A to 20C are formed, the present invention is not limited to this, and the number of the reflecting surface portions 20A to 20C may be two or three or more. Good. However, if the number of reflecting surface portions is increased infinitely to form a perfect paraboloid of revolution or a reflecting surface close to this, it is difficult to form and a light loss occurs. That is, since the reflection surface portion (20C) near the opening end of the reflection wall is substantially parallel to the optical axis, the light reflected by this reflection surface portion has a large angle with respect to the optical axis and becomes reflected light toward the outside. Therefore, it becomes a loss of light.

[0015]

[Effect of device]

 As described above, in the light emitting diode according to the present invention, since the reflecting wall of the tray on which the semiconductor chip is mounted is bent outward to form a plurality of reflecting surface portions, the reflected light reflected in the optical axis direction is not generated. It is possible to increase the amount of reflected light that has been emitted to the outside from the vicinity of the dome base of the envelope. Therefore, the loss of light is small, and the irradiation efficiency and directivity of the LED can be improved.

[Brief description of drawings]

FIG. 1 is a diagram showing a light emitting diode according to the present invention and an optical path of reflected light.

FIG. 2 is a sectional view of a tray.

FIG. 3 is a sectional view of a main part of a conventional lighting device including a light emitting diode.

FIG. 4 is a diagram showing a conventional light emitting diode and optical paths of its direct light and reflected light.

FIG. 5 is a sectional view of a saucer used in a conventional light emitting diode.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Front lens 2 Inner lens 3 Diffusing lens 4 Light emitting diode 6 Semiconductor chip 7a, 7b Lead wire 8 Gold wire 9 Receiving tray 9A Bottom plate 9B Reflecting wall 10 Envelope 10A Dome part 20A First reflecting surface part 20B Second reflecting surface part 20C Third reflective surface section

Claims (1)

[Scope of utility model registration request] 1. A dish-shaped tray having a bottom plate and a reflection wall surrounding the periphery of the bottom plate and having an inclined end whose opening end side is larger than the bottom plate, and an inner surface of which forms a reflection surface, and the tray is disposed on the bottom plate of the tray. The semiconductor chip and a semiconductor chip are molded in a cylindrical shape made of a transparent resin, and the end face on the emission side forms a dome portion at a predetermined distance from the center of the dome portion to the side opposite to the dome portion. In the diode, the reflecting wall of the tray has a plurality of reflecting surface portions having different inclination angles with respect to the optical axis by being bent so as to be convex outward.