JPS63104489A - semiconductor light emitting device - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) This invention relates to the shape of a resin lens of a semiconductor light emitting device (hereinafter abbreviated as LED), and is particularly applicable to LEDs used in outdoor equipment, etc. be done.

(Conventional technology) Conventional 1. , ED is shown in cross-section in FIG. In the figure, 101a, ], 01b are leads made of a metal lead frame, and a light emitting element chip (hereinafter abbreviated as LED chip) 102 is attached to the end (top) of one of the leads 01a. A chip bed is formed on which the electrodes are mounted, and the LED mounted here
A light reflecting surface 103 is formed to reflect light emitted to the side of the chip. In addition, the above 1
．． , one end of a bonding wire 104 that electrically connects the other electrode (upper electrode) of the ED chip is bonded. The thus formed light emitting element mount body was later subjected to casting-type sealing with a translucent resin such as epoxy resin to form a spherical resin lens 106 in the light emission direction.

FIG. 4 shows an optical path diagram of the light emitted from the chip that is applied to the LED having the above structure. The surface shape of the reflective surface 103 in the figure is
It is a paraboloid of revolution in order to reflect most of the rays that hit the reflective surface in the direction of the optical axis X.

This optical path diagram shows only a portion in consideration of the symmetry of the lens.

(Problem to be Solved by the Invention) As shown in the optical path diagram in FIG. Because it is refracted at the interface, it ultimately travels at an angle to the optical axis. In addition, light rays B and B that do not pass through the reflective surface
... is also refracted at the lens interface and travels, but it naturally follows a different trajectory from that of the light ray that exits through the reflective surface. For this reason, in designing the lens shape, it has been difficult to control both the light rays that pass through the reflective surface and the light rays that do not go through the reflective surface. In particular, with LEDs used in outdoor equipment such as automobile stop lamps or signal lights, the observation position may be 10 meters or more, and there is a problem that the light that has passed through one reflective surface may not be emitted at an effective angle. .

In view of the problems of the prior art described above, the present invention provides an improved structure of an LED, and in particular, the invention is improved so that the light emitted through the reflective surface can travel effectively.

[Structure of the invention]

(Means for Solving the Problems) A semiconductor light emitting device according to the present invention includes a light emitting device mount body including a lead on which a light emitting device chip is mounted and a light reflecting surface formed thereon, and a light emitting device mount body including a lead on which a light reflecting surface is formed, and a resin lens. The semiconductor light emitting device is characterized by having a flat portion formed at the tip of the resin lens and perpendicular to the output optical axis. Further, the resin lens is characterized in that the plane portion of the resin lens has an area approximately equal to the area of the opening of the light reflecting surface.

(Function) An LED with this effect is equipped with a flat part at the tip of the spherical lens of the IED, so that light rays that travel almost parallel to the optical axis via the reflective surface are refracted at the interface of the lens. It is also effective for observation at remote locations.

(Embodiment) Hereinafter, an embodiment of the present invention will be described with reference to FIGS. In the description, parts that are the same as in the prior art are designated by the same reference numerals as in the prior art in the drawings, and the description thereof will be omitted.

As shown in a perspective view in FIG. 1a and in a sectional view in FIG.
An example of the opening diameter of 3 is the flat part 1 having a diameter approximately equal to 5 mm.
1a is formed. The other parts have a curved surface (spherical surface) that is the same as the conventional structure.

FIG. 2 shows an optical path diagram of the light emitted from the chip in the LED having the above structure. This figure shows only a part of it in consideration of the symmetry of the lens, but as is clear from the figure, the light rays a, a, etc. reflected by the reflecting surface travel almost parallel to the optical axis,
The light passes through the flat part 11a of the resin lens and is emitted. Therefore, it can be seen that the light travels parallel to the lens interface without being affected by refraction.

Note that the present invention is effective not only when the shape of the reflecting surface is a paraboloid of revolution, but also for a reflecting surface that is a rotating surface having an inclination of 45 degrees with respect to the optical axis.

〔Effect of the invention〕

This invention has facilitated the optical design of LEDs used in outdoor equipment. Although quantitative evaluation of the effect is difficult, the effective light amount was increased by about 15% in the LED design example in Example 1 compared to the conventional structure.

[Brief explanation of the drawing]

1 and 2 show an LED according to an embodiment of the present invention, FIG. 1a is a perspective view, FIG. 1 is a sectional view, FIG. 2 is an optical path diagram, and FIGS. 3 and 4 are It takes a conventional LED,
FIG. 3 shows a sectional view, and FIG. 4 shows an optical path diagram.

Claims (2)

[Claims] (1) In a semiconductor light-emitting element in which a resin lens is formed by covering a light-emitting element mount body including a lead on which a light-emitting element chip is mounted and a light-reflecting surface is formed with a light-transmitting resin, the light-emitting surface of the resin lens 1. A semiconductor light emitting device, comprising: a curved surface portion; and a flat portion formed at the tip of a resin lens and perpendicular to an output optical axis. (2) The semiconductor light emitting device according to claim 1, wherein the flat portion of the resin lens has an area approximately equal to the area of the opening of the light reflecting surface.