JPS63168058A - Multiple output led module - Google Patents

Abstract

PURPOSE:To ensure a well-balanced optical coupling for a multiplicity of optical fibers by a method wherein a flat surface is formed on a spherical lens on its portion opposite to the portion facing an LED and the ends of a multiplicity of optical fibers are allowed to be in close contact with the flat surface. CONSTITUTION:On a spherical lens 3 facing an LED 1, there is a flat surface 4 at a portion opposite to the portion facing the LED 1. A spherical lens with a portion thereof flattened may be manufactured with ease by subjecting a spherical lens to such a process as abrading. The ends of a multiplicity of bundled optical fibers 2 are caused to be in close contact with the flat surface 4. In a multiple output LED module of this design, the output radiating from the LED 1 and entering the spherical lens 3 is converged on a flat surface 4. There is a uniform optical distribution on the flat surface 4, which ensures a well-balanced optical coupling for the multiplicity of optical fibers 2.

Description

[Detailed description of the invention] [Industrial application field]

This invention is a multi-output LED that efficiently outputs the output light of an LED (light emitting diode) through a large number of optical fibers.
Regarding modules.

[Conventional technology]

Compared to semiconductor lasers, LEDs are inferior in transmission bandwidth and transmission distance, but they are less susceptible to temperature and reflected light and have stable operation, are often inexpensive, and have long lifespans. By using this, it is possible to construct an economical and simple optical transmission system. However, this LED has a wide light emission beam angle, reaching 120 degrees in half width. Therefore, the acceptance angle is small,
It is very difficult to effectively couple light into a small diameter optical fiber, and no matter what optical system is used, the optical coupling efficiency is only a few percent. Coupling the light from an LED into one optical fiber in this way does not make effective use of the light, so conventionally, a multi-output L that couples the light from one LED into multiple optical fibers has been developed.
An ED module has been proposed. As shown in FIG. 2, a large number of optical fibers 2 are arranged radially through a lens 5 for one EDI. According to this, it is easy to selectively focus wide-angle output light onto the core portion of each optical fiber 2 by each lens 5, and the light is directed not only in a direction perpendicular to the light emitting surface of the LED 1 but also in an oblique direction. can also be efficiently coupled to the optical fiber 2, making it possible to achieve high output and multiple outputs. Therefore, by using this module, an extremely economical and simple optical distribution system can be realized, and it is being considered that this module can be used, for example, when distributing signals to each receiving end in a CATV system.

[Problems to be solved by the invention]

However, in the conventional multi-output LED module, since it is necessary to provide a lens for each of the plurality of optical fibers to be coupled, the optical axis must be adjusted for each combination of these, making manufacturing difficult. In addition, the structure is complex, and it is easy to carry out large-scale blow-ups. In particular, if a large number of optical fibers are to be coupled together, an increase in size is unavoidable, and in this case, the distance between the LED and the lens must be increased, resulting in a decrease in coupling efficiency. Therefore, in reality, the number of optical fibers cannot be increased that much. An object of the present invention is to provide a multi-output LED module that is small in size, has a simple structure, and can easily couple multiple optical fibers without reducing coupling efficiency.

[Means for solving the problem] A multi-output LED module according to the present invention includes LEDs,
A ball lens that faces this LED, and the L of the lens.
It consists of a flat surface provided on the opposite side of the ED, and a plurality of optical fibers each having an end surface in close contact with the flat surface.

[For production]

The ball lens is provided with a flat surface, and the LED is arranged on the opposite side of this flat surface, so that the output light from the LED is guided by the ball lens to the flat surface. Since the end faces of multiple optical fibers are brought into close contact with this flat surface, it becomes a spherical lens. The guided light thus enters the optical fiber. Therefore, there is no need to adjust the optical axis of each optical fiber, and since the light distribution on the flat surface of the spherical lens is uniform, light can be coupled to multiple optical fibers in a well-balanced manner, making manufacturing easier. It is suitable for mass production. Furthermore, the structure is simple with fewer components, and therefore reliability can be easily improved. Also, when coupling multiple optical fibers, by increasing the diameter of the spherical lens, the light emitted from the LED at a wide angle can be coupled to the optical fibers, reducing the coupling efficiency. I have nothing to do.

【Example】

A multi-output LED module according to an embodiment of the present invention is constructed as shown in FIG. In this Figure 1,
A ball lens 3 is made to face the LEDI, and a flat surface 4 is formed on the opposite side of the ball lens 3 from the LEDI. A ball lens 3 having such a flat surface 4 can be easily made by adding processing such as polishing one part of a normal ball lens to a flat surface. The end faces of a large number of bundled optical fibers 2 are brought into close contact with this flat surface 4. In this multi-output LED module, the output light spread over a wide angle from the LED 1 is incident on the ball lens 3 and focused on the flat surface 4 thereof. The distribution of light on the flat surface 4 becomes uniform. Since the end faces of a large number of bundled optical fibers 2 are brought into close contact with this flat surface 4, the light emitted to the outside from the flat surface 4 is incident on each of the optical fibers 2. Therefore, L
Most of the light emitted from the EDI is incident on each of the many optical fibers 2, resulting in good coupling efficiency. Since each end face of the optical fiber 2 is in close contact with the flat surface 4, there is little reflection, and the coupling efficiency is further improved. In this case, the optical axis can be adjusted between one LEDI and one ball lens 3, so a single optical fiber can be adjusted between one LEDI and one ball lens 3.
This is the same as when bonding to D, and the adjustment is extremely easy. Since the ball lens 3 is easy to process as described above, this multi-output LED module can be easily manufactured and mass-produced at low cost. Furthermore, the number of parts used is extremely small, making it easy to improve reliability. Note that when a larger number of optical fibers 2 are to be coupled, the diameter of the ball lens 3 may be increased and the area of the flat surface 4 may be increased.

【Effect of the invention】

The multi-output LED module according to the present invention has a small number of components and a simple structure, making it easy to downsize and improve reliability. Also, the lens used is 1
This makes it easy to adjust the optical axis and suitable for mass production. Furthermore, it can be optically coupled to multiple optical fibers in a well-balanced manner.
It is also possible to couple to a larger number of optical fibers without reducing coupling efficiency.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view of an embodiment of the present invention, and FIG. 2 is a schematic perspective view of a conventional example. 1... LED, 2... Optical fiber, 3... Ball lens, 4... Flat surface, 5... Lens.

Claims (1)

[Claims] (1) An LED, a spherical lens facing the LED, a flat surface of the lens provided on the opposite side of the LED, and a plurality of optical fibers each having an end surface in close contact with the flat surface. A multi-output LED module.