JPH01302874A - Optical semiconductor device - Google Patents

Abstract

PURPOSE:To improve optical characteristics of an optical semiconductor element by a method wherein a circular depressed part and a curved reflecting wall extended from a periphery of the circular depressed part are formed in a semiconductor-element mounting part of a lead frame and the optical semiconductor element mounted inside the circular depressed part and the lead frame are sealed with a light-transmitting resin. CONSTITUTION:A circular depressed part 6 and a curved reflecting wall 7 extended from a periphery of the circular depressed part 6 are formed in a semiconductor-element mounting part 1 of a lead frame; an optical semiconductor element 6 mounted inside the circular depressed part 6 and the lead frame are sealed with a light-transmitting resin 10. A diameter and a depth of said circular depressed part 6 and a curved surface of the reflecting wall 7 are set to dimensions that side light at a part 9 where the radiant intensity from the optical semiconductor element 8 is the largest in reflected in a direction of an optical axis B or that incident light is reflected toward the side part 9 where the photodetecting intensity of the optical semiconductor element 6 is largest. By this setup, the side light of a light- emitting element can be reflected efficiently to the direction of the optical axis or the incident light can be efficiently incident on the side part of a photodetecting element; accordingly, an optical characteristic of the optical semiconductor element can be improved by means of a simple constitution.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an optical semiconductor device with improved optical characteristics.

Prior Art FIGS. 4 to 6 show a conventional lead frame for an optical semiconductor device, in which 1 is a semiconductor device mounting portion, 2 is an internal lead portion, 3 is an external lead portion, and 4 is a semiconductor device. Placement part 1
It is a reflector formed in

As shown in FIGS. 6 and 6, the reflector 4 has an inverted trapezoidal cross-sectional shape, and a light emitting element (not shown) is placed on the bottom surface 4a thereof, and is sealed with resin together with the lead frame. The slope 4b of the reflector 4 is used as a reflecting wall. That is, most of the light from the light emitting element passes through the sealing resin and is irradiated forward as direct light, while the side light irradiated toward the side of the light emitting element is reflected by the slope 4b of the reflector 4 and then emitted. , is irradiated forward with direct light.

Problems to be Solved by the Invention In order to improve the optical characteristics of this type of optical semiconductor device, it is necessary to extract side light from the light emitting element in a direction perpendicular to the main light emitting surface of the element. Further, side light has a unique radiation intensity distribution depending on the element used. Therefore, it is desirable to reflect the side light from the portion with the highest radiation intensity in a direction perpendicular to the main light emitting surface of the element using the slope 4b of the reflector 4.

However, in the conventional lead frames shown in FIGS. 4 to 6, the slope 4b has a simple mortar shape extending linearly from the periphery of the bottom surface 4IL. Therefore, the side light from the light emitting elements placed on the bottom surface 4a is irradiated onto the flat slope 4b regardless of the radiation intensity distribution specific to each element, and is diffusely reflected in various directions depending on the angle of incidence. For this reason, the reflected light in the direction perpendicular to the main light emitting part that should originally be extracted becomes weak, and the optical characteristics deteriorate.

The present invention provides an optical semiconductor device that solves these conventional problems.

Means for Solving the Problem In order to achieve this object, the present invention provides a circular recess in the semiconductor element mounting portion of a lead frame and a reflective wall that curves and extends from the periphery of the circular recess. The optical semiconductor element placed inside the optical semiconductor element and the lead frame are sealed with a light-transmitting resin, and the diameter and depth of the circular recess and the curved surface of the reflective wall are determined based on the radiation intensity from the optical semiconductor element. The dimensions are set such that the side light of the largest portion is reflected in the optical axis direction, or the incident light is reflected toward the side surface portion of the optical semiconductor element where the received light intensity is greatest.

By doing this, it is possible to reflect the side light of the maximum radiation intensity part specific to each light emitting element in the optical axis direction, or to make the incident light enter the side part of each light receiving element having the highest light receiving intensity. Therefore, the optical characteristics of the optical semiconductor device can be significantly improved.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to FIGS. 1 to 3.

In FIGS. 1 to 3, reference numeral 1 denotes a semiconductor element mounting portion of a lead frame, 2 an internal lead portion, and 3 an external lead portion, and these structures are the same as those of the prior art. Reference numeral 5 denotes a reflector provided at the center of the semiconductor device section 1, which includes a circular depression 6 and a reflecting wall 7 extending in a curved manner from the periphery of the circular depression 6.
I am prepared for this. 8 is a light emitting element placed on the bottom surface of the circular recess 6; 9 is a side surface of the light emitting element 8 with maximum radiation intensity; 10 is a translucent resin that integrally seals the lead frame and the light emitting element 8; 11 is reflected light.

In this example, the thickness of the light emitting element 8 is approximately 100 μm.
The maximum side light radiation intensity portion 9 is located approximately 10 μm from the upper end of the light emitting element 8.

Therefore, in this embodiment, in order to effectively reflect the side light from the maximum side light radiation intensity portion 9 in a direction substantially parallel to the optical axis B, the diameter of the circular depression 6 is C345 mm.

The depth is set to 0.05 mm, and the reflecting wall 7 has a curved surface with a radius of curvature of 0.39 mm. In this way, as shown in FIG. 3, the part of the side light with the highest energy is reflected by the curved reflecting wall, and most of the reflected light 11 is emitted parallel to the optical axis B. In fact, according to this embodiment, the optical characteristics were improved by about 20% compared to when the conventional reflector 4 was used.

The size of the circular depression 6 and the radius of curvature of the reflective wall 7 are as follows:
It goes without saying that the optimum value may be determined based on the size of the light emitting element 8 used and the position of the maximum side light radiation intensity. Furthermore, although a light emitting element was used as the optical semiconductor element in the above embodiment, a light receiving element may also be used. In this case, the radius of curvature of the reflective wall 7 and the diameter and depth of the circular recess 6 may be set so that the light reflected by the reflective wall 7 enters the part of the side surface of the light receiving element where the light reception is greatest. .

Effects of the Invention According to the present invention, side light of a light emitting element can be efficiently reflected in the optical axis direction, and incident light can be efficiently made to enter a side part of a light receiving element, so that a simple configuration is possible. , the optical characteristics of the optical semiconductor device can be significantly improved.

[Brief explanation of the drawing]

Fig. 1 is a plan view of a lead frame used in an embodiment of the present invention, Fig. 2 is a sectional view of the same embodiment, Fig. 3 is an enlarged sectional view of the reflector portion of Fig. 2, and Fig. 4. Figure 6 is a plan view and a cross-sectional view of a lead frame used in a conventional optical semiconductor device,
FIG. 6 is an enlarged sectional view of a portion of a conventional reflector. 1... Semiconductor element mounting part, 2... Internal lead part, F... External lead part, 6...
・Reflector, θ...Circular depression, 7...
Reflective wall, 8...Light emitting element, 9...Maximum side light radiation intensity part, 10...Resin, 11...
··reflected light. Name of agent: Patent attorney Toshio Nakao and 1 other person18
6. Shizuku” - [I

Claims (1)

[Claims] A circular depression in the semiconductor element mounting part of the lead frame,
A reflective wall is provided that curves and extends from the periphery of the circular recess, and the optical semiconductor element placed in the circular recess and the lead frame are sealed with a translucent resin. The depth and the curved surface of the reflecting wall reflect side light from the optical semiconductor element at the portion where the radiation intensity is highest in the optical axis direction, or the incident light is reflected at the side surface portion where the light reception intensity is highest at the optical semiconductor element. What is claimed is: 1. An optical semiconductor device characterized in that the dimensions are set to reflect light toward.