JPH0436591B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a light emitting diode that emits visible light or infrared rays and is used as a light source for various sensors, particularly as a light source for optical communication devices.

[Prior Art] An example generally used as a light source for this type of optical communication is shown in FIG. In the figure, 1 is an LED, 2 is an optical fiber, and the LED 1 is disposed close to the end of the optical fiber 2.
A substantially parallel light beam a emitted from the front surface of the optical fiber 2 reaches the optical fiber 2,
The luminous flux b exiting from the side of the LED 1 is completely wasted luminous flux. Therefore, of the luminous flux emitted from the entire LED 1, only about 1/3 of the luminous flux is effectively used, and the majority is not utilized and becomes wasted emitted light. This large amount of wasted radiation causes a substantial reduction in illuminance,
The use of dark LEDs poses various problems in optical communications.

Regarding the effective use of luminous flux in the LED itself,
There is an earlier application (Japanese Patent Application No. 59-270372) filed by the same applicant. The invention of this earlier application attaches a cap (reflection member) to the LED, and the cap reflects the luminous flux emitted from the side of the LED toward the front side.
We are trying to increase the overall illuminance, but since the luminous flux emitted from the front side is approximately parallel,
For example, when used as a light source in combination with an optical fiber for optical communication, the area of the front surface of the cap is larger than the area of the end of the optical fiber, and the light beam emitted from the front surface protrudes from the end of the optical fiber. Therefore, even if the light beam emitted from the sides is directed toward the front side, essentially only the light emitted from the front side of the LED itself can be used, and there is a problem that the illuminance cannot be increased.

[Problems to be solved by the invention] The present invention has the problems of the conventional method due to the fact that only a part of the luminous flux emitted from the LED can be used and the illuminance of optical communication decreases, and even if the luminous flux emitted from the side is directed to the front side. This is an attempt to solve the problem that the light is not incident on the end of the optical fiber.

[Means for Solving the Problems] As a specific configuration for solving the above problems, the present invention includes an LED main body and a light-transmissive reflective member fitted to the LED main body, and the reflective member A through hole into which the LED body fits is formed in the center,
The back side is formed into a dome-shaped curved surface that reflects the luminous flux emitted from the side surface of the LED body toward the front side as substantially parallel rays, and the front side is provided with a convex lens cut to condense the parallel rays. The present invention aims to provide a light emitting diode characterized by the following: By forming the front surface of the reflecting member into a convex lens cut, the light beam radiated to the side surface is reflected to the front side by a dome-shaped curved surface, and then the light emitting diode is cut into a convex lens. Since the light is taken out through the cut, it is focused at a certain distance by a convex lens cut, and by positioning the end of the optical fiber at a certain distance, most of the light flux emitted from the LED enters the optical fiber. Therefore, the illuminance can be increased.

[Examples] Next, the present invention will be explained in more detail with reference to illustrated examples. In order to facilitate understanding, the same parts as in the conventional example will be described with the same reference numerals. Reference numeral 1 denotes an LED main body that is generally used as a light source for an optical fiber 2. A light emitting element 5 is mounted on one of a pair of lead frames 3 and 4, and a wire is connected between the LED main body and the other lead frame. 6 is a bonded configuration.

A reflective member 7 made of a light-transmissive material such as resin or rubber is attached to the LED body 1.
This reflective member has a generally bowl-shaped overall shape,
Cylindrical through hole 8 that penetrates from the front to the back in the center
The through hole is formed so that it is slightly wider on the front side and gradually narrows toward the back side, and on the back side, the range where the LED body 1 fits is slightly parallel or parallel to the LED body 1. It is formed to match the outer circumference. The LED body 1 is inserted into the through hole 8 from the rear side, so that the circular lens portion 1a at the top of the LED body 1 is exposed inside the through hole 8.

The reflective member 7 is formed into a dome-shaped curved surface 9 from its side to the back side, and the LED main body 1
The light beam b exiting from the side surface is reflected by the curved surface 9 to become a substantially parallel light beam b' toward the front side. A convex lens cut 10 is provided on the front side of the reflecting member 7 so that the parallel light beam b' is focused at a certain distance, and the light beam passing through the convex lens cut 10 is located at the end of the optical fiber 2 at a certain distance. The light is focused on. In addition, the lens part 1a of the LED main body 1
The light beam a emitted from the optical fiber 2 passes through the through hole 8 as it is and reaches the end of the optical fiber 2. Therefore, at the end of the optical fiber 2, the front surface of the LED body 1, that is, the lens portion 1
The luminous flux a emitted from the LED main body 1 and the luminous flux b emitted from the side of the LED main body 1 are superimposed on each other, and even when using the LED main body 1 of the same brightness, the brightness is higher than that of a conventional light source. will double. In addition, the code 7a in the figure is the hem part, and the LED body 1
This stabilizes the retention of

[Effects of the Invention] As explained above, the light emitting diode according to the present invention is used particularly as a light source of an optical communication device, in which a light-transmitting reflective member is attached to the LED body, and a light-transmitting reflective member is attached to the back surface of the reflective member. By forming the side into a dome-shaped curved surface and the front side having a convex lens cut, the luminous flux emitted from the LED body to the front side is used as is, and the luminous flux emitted to the side of the LED is The dome-shaped curved surface reflects the light as approximately parallel light to the front side, and the convex lens cut on the front focuses the light at a certain distance, making the brightness of the incident light at the end of the optical fiber for optical communications much lower than that of conventional It has the excellent effect of being twice as large as LEDs, eliminating the inconveniences caused by reduced illuminance in conventional optical communication between remote locations, and being able to use commonly used LEDs as is. .

[Brief explanation of drawings]

FIG. 1 is a sectional view of a light emitting diode according to the present invention, FIG. 2 is a perspective view of the same light emitting diode, and FIG. 3 is a schematic diagram showing a conventional optical communication light source. 1... LED body, 2... Optical fiber, 3, 4... Lead frame, 5... Light emitting element, 6... Wire, 7... Reflective member, 8... Through hole, 9... Dome-shaped Curved surface, 10... Convex lens cut, a... Luminous flux emitted from the front of the LED,
b... Luminous flux emitted from the side of the LED.

[Claims]

1 Consists of an LED main body and a light-transmissive reflective member with a through hole in the center into which the LED main body fits, and the back side of the reflective member reflects the light flux emitted from the LED main body in the lateral direction. A dome-shaped first curved surface and a second curved surface are formed to reflect substantially parallel light to the side, and an inverted V-shaped groove is provided between the first curved surface and the second curved surface. Features a light emitting diode.