JPS60213069A - Led for optical communication - Google Patents

Abstract

PURPOSE:To simplify structure and assembly, and to compact the titled LED by positioning one focus of an elliptical mirror fitted on a beam extracting surface at a light-emitting section, crossing a straight line tying two focuses at right angles with a mirror surface and mounting a lens for shaping parallel luminous flux to an opening at the central section of the mirror. CONSTITUTION:An elliptical mirror 11 is positioned to an LED element, and the length of the major axis and minor axis of an ellipse are selected properly. Beams emitted from a light-emitting section 2 project into air from an LED element 1, are reflected by the elliptical mirror 1 and enter into the LED element again, are reflected from a mirror surface 13 and project from the LED element again, and are condensed to approximately the central section of the elliptical mirror 11. Consequently, parallel luminous flux 23 having a diameter smaller than the core diameter of an optical fiber 3 can be formed easily by a small lens 19 for shaping parallel luminous flux fitted at the position of the central section. Accordingly, a condensing system can be assembled only by integrally forming the elliptical mirror 11 and lenses 19, 21 and fitting the elliptical mirror onto the LED element.

Description

[Detailed Description of the Invention] The present invention relates to an LED (light emitting diode) for optical communication;
More specifically, the present invention relates to an LED for optical communication equipped with a condensing system that can efficiently input emitted light power into an optical fiber.

Conventionally, in order to efficiently input the light emitting power of an LED for optical communication into an optical fiber, a condensing system is required. The light emitted from the LED element 1 can be Once the light is focused, it is converted into a parallel light beam with a diameter less than the core diameter, and then input into an optical fiber. However, the above condensing system uses at least two lenses to accurately position the light emitted from the LED element 1 with respect to the LED element in order to once condense the light emitted from the LED element 1 and make it enter the optical fiber 3 as a parallel beam. The structure and assembly of the condensing system are complicated, and the light emitted from the LED element into the air has a large divergence angle, so it is necessary to increase the diameter of the convex lens 5 to condense this light. This has the disadvantage that the size of the condensing system becomes large.

The present invention has been made to eliminate the above-mentioned conventional drawbacks.
Therefore, in the optical communication LED according to the present invention, an elliptical mirror is attached on the light extraction surface of the LED element, one focal point of the mirror is positioned on the light emitting part of the LED element, and the two focal points of the mirror are connected. A straight line is made perpendicular to the mirror surface on the opposite side of the light extraction surface of the element, and a lens for forming a parallel beam is attached to the aperture provided in the center of the Kl mirror, and the condensing system is
It is characterized by being integrated onto the ED element.

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

3 and 4 each show an embodiment of the present invention, in which an elliptical mirror (spheroidal surface) 11 is mounted on the light emitting surface of the LED element 1. One focal point f1 of the mirror 11 is located on the light emitting part 2 of the LED element 1, and the two focal points f, , f of the mirror 110 are
2 is made perpendicular to the mirror surface 13 on the opposite side to the light extraction surface of the LED element, for example, the Au plating surface between the header or heat sink 15 and the element 1, and an opening 17 is formed in the center of the mirror 11. A concave lens 19 (FIG. 3) or a convex lens 21 (FIG. 4) for forming a parallel light beam is attached inside the aperture 17.

By positioning the elliptical mirror 11 with respect to the LED element as described above and appropriately selecting the lengths of the long and short axes of the ellipse, the light emitted from the light emitting part 2 is directed away from the LED element 1 into the air. After exiting to the elliptical mirror 11Vc as shown,
After being reflected by the mirror surface 13 and exiting the LED element again, the elliptical mirror 1
The light is focused on approximately the center of the image. Therefore, the parallel light beam 2 having a diameter smaller than the core diameter of the optical fiber 3 is generated by the small concave lens 19 or the convex lens 21 provided at the position.
3 can be easily formed.

In the case formed in this way, the elliptical mirror 11 and lenses 19 and 21 are integrally formed, and the condensing system can be assembled by simply attaching the elliptical mirror to the LED element, so the structure and assembly are simple. It can be simplified.

Further, since the elliptical mirror 11 has the same dimensions as the LED element 1 and tl and is disposed in close contact with the LED element, the entire condensing system can be made compact. Furthermore, in some cases, the input end of the optical fiber 3 may be directly connected to the elliptical mirror 11.
Therefore, the positional relationship between the optical fiber 3 and the LED element 1 will not shift due to changes over time.

In addition, in order to facilitate light emission from the LED element 1 into the air, the space between the elliptical mirror 11 and the LED element 1 is
The refractive index n2 is the refractive index n1 of the element and the refractive index n of air. against n. It can be filled with a substance that satisfies ≦n2≦n. The darning material can be, for example, the same material as the lens 19.21.

As described above, according to the present invention, in order to efficiently input light emitted from an LED element into an optical fiber, an LE for optical communication is provided with a compact condensing system that is simple in structure and assembly.
A D element is provided.

[Brief explanation of the drawing]

FIGS. 1 and 2 are diagrams each showing an example of a condensing system arranged between a conventional LED and an optical fiber, and FIGS. 3 and 4 are diagrams each showing an embodiment of the present invention. 1...LED element, 2...light emitting part, 3...
... Optical fiber, 11... Oval mirror, 13
...Mirror surface, 1γ aperture, 19...Concave lens, 21...Convex lens. Patent applicant: Sumitomo Electric Industries, Ltd. (4 others) Figure 1 Figure 3"fz Figure 4

Claims (3)

[Claims] (1) Mount an elliptical mirror on the light extraction surface of the LED element, position one focal point of the mirror on the light emitting part of the LED element, and connect the two focal points of the mirror with a straight line on the light extraction surface of the element. LED0 for optical communication, characterized in that a lens for forming a parallel light beam is attached to an aperture provided in the center of the mirror, which is perpendicular to the mirror surface on the opposite side. (2) The space between the elliptical mirror and the element has a refractive index n2 equal to the refractive index 111 of the element and the refractive index n of air. against n. LED0 for optical communication according to claim 1, characterized in that it is filled with a substance such that ≦n2≦n. (3) The LED for optical communication according to claim 2, wherein the material is made of the same material as the lens.