Optoelectronic semiconductor component

An optoelectronic semiconductor component applies to a surface mount component of an optoelectronic semiconductor. The optoelectronic semiconductor component has one or more semiconductor chip secured on a chip carrier. The chip carrier is a part of a lead frame, and another part of the lead frame is formed with an independent connection part as a contact of the semiconductor chip. An encapsulation body centers on the semiconductor chip and encircles part of the chip carrier and the independent connection part to form an annular ellipsoid for reflecting or receiving radiation of the semiconductor chip. The encapsulation body has a recess and a window part filling the recess. The window part is composed of materials for transforming the optical characteristics of the semiconductor chip. Part of the chip carrier and the independent connection part extend out the encapsulation body to form outside contacts as a SMT component.

BACKGROUND OF THE INVENTION

This Nonprovisional application claims priority under 35 U.S.C. 119(a) on patent application Ser. No(s). 93204267 filed in Taiwan, Republic of China on Mar. 19, 2004, the entire contents of which are hereby incorporated by reference.

1. Field of the Invention

The present invention relates to an optoelectronic semiconductor component, and particularly to an SMT-type (surface mounted technology-type) optoelectronic semiconductor component for illumination that can be applied as a backlight source or a light interceptor.

2. Description of the Prior Art

LED (Light Emitting Diode) is a kind of solid-state illuminant that is small-scale and has high lighting efficiency. It has a long lifespan and high stability. LED is adopted as various types of light sources, such as a light source for a monitor, a backlight board, a traffic signal, emergency exits, or decorative illumination, because LED is a kind of semiconductor component.

Similar optoelectronic semiconductor modules have been disclosed, as in U.S. Pat. No. D478877 (shown inFIGS. 1 and 2) which has been issued on Aug. 26, 2003 and R.O.C. patent number 315528 (shown inFIGS. 3 and 4) which has been issued on Sep. 11, 1997. The above-mentioned patents disclose a kind of radiation-emitting or radiation-receiving semiconductor module, which has one or more emitting or receiving semiconductor chip fixed on a chip carrier of a lead frame. A portion on which the semiconductor chip fixed is of a plane-type or formed as a nest. An inner surface of the nest is designed as a reflecting curved surface for emitting or receiving light. The semiconductor chip and at least one part of the chip carrier are encircled by an encapsulation body. The encapsulation body defines a reflecting curved surface for emitting or receiving light, thereby forming an optoelectronic semiconductor module.

The above-mentioned prior arts have some problems, which are described as follows:

1. In U.S. Pat. No. D4778877S of the prior art, an optoelectronic semiconductor module80includes a chip carrier82formed by a lead frame. The chip carrier82lacks a chip central position mark, so a chip84cannot be fixed accurately and results in the semiconductor chip84emitting disproportionately. Moreover, an encapsulation body86is a polyhedron and has an asymmetrical structure, so that it is effected easily by outside forces. For example, when the semiconductor chip84is illuminated, the encapsulation body86is heated and the resulting stress is not equalized easily, which will deform an optical reflection curved surface88and the radiating light of the semiconductor chip84will not be well-proportioned.

2. In R.O.C. patent number 315528 of the prior art, an optoelectronic semiconductor module90includes a chip carrier92, an independent link-part94, and an encapsulation body96encircling the chip carrier92and the independent link-part94. The chip carrier92and the independent link-part94respectively extend under the encapsulation body96to form outer electric contacts97,98. Such a structure cannot make the light direction parallel to the PCB, thus limiting the use thereof.

Therefore, the optoelectronic semiconductor module of the prior art still has some inconvenience and disadvantages to be improved.

SUMMARY OF THE INVENTION

The present invention provides an optoelectronic semiconductor component that has an improved encapsulation body for resisting the influence of outer forces and further lowering total strain, in particular the deformation of an optical reflection curved-surface. Therefore, the curvature precision of the optical reflection curved-surface is increased, the illumination efficiency of the semiconductor chip is enhanced, and emission is uniform.

The present invention further provides an optoelectronic semiconductor component that fixes the chip accurately, so that the semiconductor chip emits uniformly and increases the combinative ability of the chip with the chip carrier of lead frame, therefore enhancing the reliability of the optoelectronic semiconductor component.

The present invention provides an optoelectronic semiconductor component, which comprises a lead frame, at least one radiation-emitting/or radiation-receiving semiconductor chip, an encapsulation body, an optical window part, and a pair of outside connecting parts. The lead frame has a chip carrier and an independent link-part. The chip carrier is formed with a central position mark thereon and defined as an inner electrical contact. The independent link-part is another inner electrical contact. The semiconductor chip is secured on the chip carrier and is electrically connected with the chip carrier and the independent link-part via leads, respectively. The encapsulation body is formed with an axial-symmetrical arc section, which is centered on the semiconductor chip. An inner surface of the encapsulation body encircles a part of the chip carrier and the independent link-part to define an annular ellipsoid. The optical window part is formed in a concave portion of the annular ellipsoid and is filled with a material for transforming optical characteristic of emitted/or received light from the semiconductor chip. The pair of outside connecting parts respectively extends from the chip carrier and the independent link-part, and is exposed by the encapsulation body as outer contacts; thereby resisting the influence of external force, reducing total strain, and increasing the curvature precision of the optical-reflecting curved surface to enhance the emitting efficiency of the semiconductor chip and solve the light loss of such kind illumination structure.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring toFIGS. 5 to 9, an optoelectronic semiconductor component of the present invention is illustrated respectively in different views. The optoelectronic semiconductor component1has a semiconductor chip11, a lead frame (12,13), an encapsulation body14, an optical window part16, and a pair of fixing portions17,18.

The semiconductor chip11can be one or more in number. The semiconductor chip11can be a radiation-emitting or a radiation-receiving semiconductor chip. The emitting semiconductor chip can be used as a light source, and the receiving semiconductor chip can be used as a light interceptor.

The lead frame has a chip carrier12, and an independent link-part13. The semiconductor chip11is secured on the chip carrier12. The semiconductor chip11is electrically connected with the chip carrier12and the independent link-part13via leads112,114, respectively. The chip carrier12is formed with a central position mark122on a top surface thereof. The central position mark122is defined as an inner electrical contact, and assists in the semiconductor chip11being fixed accurately at a center of the chip carrier12. Therefore, the semiconductor chip emits uniform light. The independent link-part13is another inner electrical contact. The central position mark122is concave from a top surface thereof and is shaped as a “+”. The central position mark22can be a circle, a square, a triangular, a cross, a right-angle, or a combination of above-mentioned shapes. To increase illumination efficiency, a surface of the chip carrier12is further coated with a material for enhancing reflection.

The encapsulation body14is an annular shell, and is formed with an axial-symmetrical arc section centered on the semiconductor chip11. An inner surface of the encapsulation body14encircles a part of the chip carrier12and the independent link-part13to define an annular ellipsoid15. The annular ellipsoid15has an optical focus of the central position mark122. The annular ellipsoid15of the encapsulation body14is made of a highly reflective material and forms a smooth curved surface. Alternatively, the annular ellipsoid15of the encapsulation body14is coated with a material for enhancing reflection and forms a smooth curved surface. With the encapsulation body14, the deformation according to such a structure is more proportional and will not result in a deformation of the optical reflection curved-surface. The semiconductor chip11still maintains uniform emission.

The optical window part16is formed in a concave portion of the encapsulation body14, which is a hollow part of the annular ellipsoid15. The optical window part16is filled with a material for transforming the optical characteristics of light emitted from the semiconductor chip11. The material for transforming the optical characteristics of light emitted from the semiconductor chip11can be epoxy resin or silica gel, and consists of fluorescent material, light-mixed material or pigment. For example, when a fluorescent material is added, it absorbs light emitted from the semiconductor chip and radiates another wavelength light.

The pair of fixing portions17,18extend outwardly from two sides of the encapsulation body14. The fixing portions17,18are generally L-shaped, and each has a horizontal portion172,182parallel to the light emission direction. The optoelectronic semiconductor component1further has a pair of outside connecting parts174,184respectively extending from the chip carrier12and the independent link-part13. The pair of outside connecting parts174,184are respectively disposed beneath the horizontal portions172,182to be exposed by the encapsulation body14as outer contacts, thereby forming the surface mounted technology component1.

FIG. 10illustrates a perspective view of the optoelectronic semiconductor component assembled on a PCB. The outside connecting parts174,184are formed on the bottom of the horizontal portions172,182of the fixing portions17,18. The optoelectronic semiconductor component1is thereby soldered on a PCB2parallel to the radiation direction. The present invention is thus easily used as a backlight.

FIG. 11illustrates a front view of the optoelectronic semiconductor component of second embodiment according to the present invention. The optoelectronic semiconductor component1acan be mounted with more than one semiconductor chips11,11awith different function. For example, mounting with two LED semiconductor chips to meet the requirement of better illumination and enhance the reliability of the LED semiconductor chips, or mounting with another one diode-protective chip to protect the semiconductor chip11from excessive current, such as a Zener diode. The Zener diode can adjust working voltage and has function of stabilizing circuit. The optoelectronic semiconductor component1a is formed with two central position marks122,123on the chip carrier12to orientate the semiconductor chips11,11a. The semiconductor chips11,11aare parallel or series connection via the leads112,113,114.

FIG. 12illustrates a side view of the optoelectronic semiconductor component of second embodiment according to the present invention. The fixing portions of the optoelectronic semiconductor component could be extending from the independent link-part13and the chip carrier12and bended as outer electric contacts. In this embodiment, the optoelectronic semiconductor component1ahas a pair of fixing portions17a,18athat are formed into different shape from the first embodiment. The fixing portions17a,18aare extending along the encapsulation body14downwardly and outwardly. From the front view, the fixing portions17a,18aare generally L-shaped and have horizontal portions172a,182a.

FIG. 13,14illustrate a front view of the optoelectronic semiconductor component of third embodiment according to the present invention, and a side view of the optoelectronic semiconductor component assembled on a PCB. The fixing portions17a,18aof the optoelectronic semiconductor component1aare formed into slab-shape that are extending outside the encapsulation body14and perpendicular to the emission direction. The optoelectronic semiconductor component1atherefore can be soldered on PCB2vertically.

The geometric structure of the outer electric contacts of the present invention can reduce the contact resist and increase the heat-conductive factor to enhance the emitting efficiency of the semiconductor chip and solve the light loss of such kind illumination structure.

A summary of the characteristics and advantages of the optoelectronic semiconductor component is given as follows.

The encapsulation body14of the present invention is an arc with an axial-symmetrical section along inner and outer edges thereof, so that it can resist the influence of outer forces and further lower total strain. Therefore, the curvature precision of the optical reflection curved-surface is increased, illumination efficiency of the semiconductor chip is enhanced, and emission is uniform. Especially when applied as a backlight, the present invention can prevent light loss in illumination structures. The present invention provides the chip carrier12, which is formed with a central position mark122, so that the semiconductor chip11emits uniformly and increases the combinative ability of the chip11with the chip carrier12of the lead frame, therefore enhancing the reliability of the optoelectronic semiconductor component.