Semiconductor element string structure

A semiconductor element string having a number of semiconductor elements mounted on a lead frame. The lead frame has a transverse plate, an assembling plate and a number of first and second leads respectively connected to the transverse plate and the assembling plate. The lead frame is used to form the semiconductor element string by soldering the semiconductor elements on the end portions of the first and second leads. When forming the semiconductor element string, one of the leads of each of the semiconductor elements in the string is connected to the transverse plate.

BACKGROUND OF THE INVENTION 
This invention relates to a semiconductor element string structure, and 
more particularly, to a light emitting diode (LED) string which can be 
used for a display board or the like. During the manufacture of the LED 
strings, both leads of a plurality of the LED chips are connected with a 
transverse plate to form a semiconductor element string. After the LEDs 
are furnished, one lead of each LED chip is cut off from the transverse 
plate and another lead is still connected to the transverse plate. 
Therefore, such an LED string can be conveniently positioned to a printed 
circuit board in order to increase its assembling rate, thus not only 
decreasing the number of necessary connections to the printed circuit 
board but also simplifying the design of the printed circuit boards. 
As is well known in conventional techniques, LEDs have often been formed as 
a single element. When used to form a large LED display, it is necessary 
to position all of the LEDs on a circuit board and make necessary 
electrical connections. However, this arrangement has two major drawbacks: 
1. It takes a lot of time to assemble the separate LEDs into a large LED 
display and is therefore inefficient for use in forming such a display. 
2. The ciruit board used to position every LED thereon is very complicated 
in its circuit layout. For example, if there are 400 LEDs on the board, 
then it is necessary to connect 800 pins into a desired matrix form and to 
align the LEDs in a correct position. The work of the assemblage is 
obviously difficult and expensive. Moreover, it is very difficult to 
connect so many pins on a one-layer circuit board, and of course, the cost 
of manufacturing is greatly increased. 
3. All the LEDs cannot be easily aligned with one another. The 
inappropriate assemblage of LEDs on the board tend to cause the LEDs to 
misalign with one another. 
It is, therefore, the purpose of this invention to mitigate and/or obviate 
the above-mentioned drawbacks in the manner set forth in the detailed 
description of the preferred embodiment. 
SUMMARY OF THE INVENTION 
A primary objective of this invention is to provide a semiconductor element 
string, in which a plurality of semiconductor elements are made into a 
semiconductor element string by connecting one lead of each semiconductor 
element to a transverse plate; therefore, the number of necessary 
connections to the printed circuit board is greatly decreased when it is 
desired to mount a large number of the semiconductor elements on the 
printed circuit board. 
Another objective of this invention is to provide a semiconductor element 
string by which all the semiconductor elements can be easily positioned 
and can be neatly aligned. 
Further objectives and advantages of this invention will become apparent as 
the following decription proceeds, and the features of novelty which 
characterize the invention will be pointed out with particularity in the 
claims annexed to and forming a part of this invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
With reference to the drawings and particularly to FIG. 1 thereof, it can 
be seen that a lead frame 10 in accordance with the present invention 
substantially comprises a transverse plate 2, an assembling plate 3 and a 
plurality of first and second leads 11 and 12, in which the first leads 11 
are electrically connected to the transverse plate 2, and the second leads 
are electrically connected to the assembling plate 3. 
Between the end portions of a pair of the first and second leads 11 and 12, 
a semiconductor element 1 indicated in dotted circles is soldered on the 
ends thereof by a bonder (not shown), in which the end portions thereof 
are slanted and in alignment with each other. Corresponding to each of the 
semiconductor elements, the transverse plate 2 has a respective protruding 
piece 21 to be connected to a respective first lead 11. The assembling 
plate 3 has an assembling hole 30 so as to facilitate the automatic 
manufacturing process. 
Parallel to each pair of the first and second leads 11 and 12, a third lead 
13 with a tap 130 is interposed between the transverse plate 2 and the 
assembling plate 3 to either serve as a lead of a semiconductor element 
with three leads by adhering the tap 130 to the semiconductor element or 
to reinforce the configuration of the lead frame if the semiconductor 
element has only two leads. Moreover, parallel to the assembling plate 3, 
a linking piece 4 is provided crossing over respective middle portions of 
the second and third leads 12 and 13 so as to make the whole construction 
more stable. 
When forming the structure of this invention, the protruding pieces 21 are 
cut off from the transverse plate 2, excepting two protruding pieces 20 
which are, not exclusively, the outermost protruding pieces 20, as shown 
in FIG. 2. Each second lead 12 is cut off from the assembling plate 3, and 
each third lead 13 is cut off from the transverse piece 2, if the 
semiconductor elements have two leads; for example, LEDs. Moreover, the 
linking piece 4 is cut off from all the second leads 12 to isolate the 
second leads 12 of the semiconductor elements from one another. Further 
referring to FIG. 3, another preferred embodiment is shown similar to that 
in FIG. 2, but all of the third leads 13 with the taps 130 soldered on the 
corresponding semiconductor elements are cut off from the assembling plate 
3 and the transverse plate 2, since the semiconductor elements have three 
leads. As mentioned above, the unnecessary portions indicated in dotted 
lines are cut off from the lead frame 10, and the remaining portions 
indicated in solid lines are used to form the semiconductor element string 
of this invention. 
After the work of cutting off all the unnecessary portions from the lead 
frame 10, all of the first and second leads 11 and 12 are folded to bend 
90 degrees in a manner that the semiconductor elements 1 with the slanted 
portions of the first and second leads 11 and 12 are juxtaposed to one 
another, as shown in FIG. 4. This results in facilitating the assemblage 
of the semiconductor elements. Obviously, the remaining protruding pieces 
21 face downward with respect to the semiconductor elements 1 and can be 
inserted into a circuit board. It should be noted that the number of the 
semiconductor elements to used form a semiconductor element string is not 
exclusive and is dependent on the actual requirements. 
Further, similar to the embodiment shown in FIG. 4, other preferred 
embodiments of the semiconductor elements with three leads are illustrated 
in FIG. 5, in which two LED chips are contained in every semiconductor 
element and can emit two different colors of light. In this situation 
there are three connecting leads 11, 12 and 13 (the first lead 11 of which 
is not shown), with the first lead 11 connected to the transverse plate 2 
and serving as the common line. In addition, this structure can be applied 
with transistors too, as demonstrated in FIG. 6. According to the 
semiconductor element string, all of the first leads 11 are connected to 
one another by the transverse plate 2, thus greatly decreasing the number 
of necessary connections to the printed circuit board (i.e., one half of 
the original number). 
When mounting the semiconductor element string on the printed circuit 
board, the transverse plate 2 is fixed thereon and causes all the 
semiconductor elements to be positioned at the same level. Furthermore, 
the transverse plate 2 also has the effect of further securing the 
connections of the semiconductor elements on the printed circuit board, 
whereby the large LED display is formed effectively as well as 
efficiently. Please note that each end of the transverse plate 2 can be 
bent inward or outward, so that two or more semiconductor element strings 
can be aligned and overlap with each other, as shown in FIG. 7. 
As can be seen from the above description, this invention provides a 
semiconductor element string which not only greatly reduces the time 
needed for the assemblage of the semiconductor elements into a printed 
circuit board, but also significantly simplifies the design of the printed 
circuit board in connection with the large display. That is, the present 
invention provides the following advantages: 
(1) Provides easier and more convenient fabrication than previously 
possible since a series of the semiconductor elements are mounted together 
in actual use; 
(2) Simplifies circuit design by previously connecting one lead of all the 
semiconductor elements in a string as the ground line. This results in 
reducing the points required to be soldered and reducing a lot of 
connections to the printed circuit board as the groound lines for 
respective semiconductor elements; 
(3) Enhances security of the connections of the semiconductor elements on a 
printed circuit board, since the semiconductor elements are connected to 
the transverse plate. This reduces a lot of connecting contacts which 
require inspection; and 
(4) It is convenient to multiply the amount of the semiconductor elements 
by contacting the end portions of the transverse plates. 
Various possible embodiments might be made of the above invention without 
departing from the scope of the invention; for example, the light emitting 
diode may be substituted by transistor. It is to be understood that all 
matter herein described or shown in the accompanying drawings is to be 
interpreted as illustrative and not in a limiting sense. Thus it will be 
appreciated that the drawings are exemplary of a preferred embodiment of 
the invention and that the scope of the invention is to be limited only by 
the scope of the appended claims.