US20070152486A1

US20070152486A1 - Mounting seat for an integrated circuit and a circuit board and method of manufacturing the same

Info

Publication number: US20070152486A1
Application number: US11/540,395
Authority: US
Inventors: Huei-Long Lee; Shun-Fa Chen; Simon D. Shong; T. L. Yeh; C. L. Chu
Original assignee: Porite Taiwan Co Ltd
Current assignee: Porite Taiwan Co Ltd
Priority date: 2005-12-30
Filing date: 2006-09-29
Publication date: 2007-07-05
Also published as: TWI318859B; TW200726372A

Abstract

A mounting seat for an integrated circuit (IC) and a circuit board includes a base formed by way of powder metallurgy, two pin holes formed on the base, and two positioning pins, which may be respectively formed in the pin holes by way of insert molding or inserted into the pin holes by way of assembling. Thus, a surface of the base may be quickly molded to form the positioning pins or assembled with the positioning pins, which are made of a material different from that of the base. Consequently, the method of manufacturing the mounting seat is simple and timesaving, and the manufacturing cost can be reduced.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention
The invention relates in general to a mounting seat for an integrated circuit (IC) and a circuit board, and more particularly to a mounting seat for mounting a digital micromirror device (DMD) made by MEMS technology and a circuit board.
2. Prior Art
A typical mounting seat for an integrated circuit (IC) or a microprocessor is a block-like body, and a surface of the mounting seat is formed with a plurality of terminal holes. The mounting seat is adhered onto a surface of a circuit board, and electrical connection points of the mounting seat are electrically connected to circuits of the circuit board. The IC or microprocessor has protruding terminals, which are inserted into the terminal holes of the mounting seat. Thus, the IC or the microprocessor can be electrically connected to the circuits of the circuit board.
In addition, MEMS devices have been widely used in digital image products such as projectors, digital televisions, and the like. For example, Texas Instruments Incorporated has proposed a digital micromirror device (DMD), which has made using the MEMS technology, in conjunction with the digital light processing (DLP) to constitute the optical architecture of a projector.
The DMD has to be placed on a mounting seat, on which a circuit board to be electrically connected to the DMD is disposed. For example, U.S. Pat. No. 6,894,853 discloses a micromirror device, which is disposed on a surface of a ceramic seat, and a printed circuit board is adhered to the other surface of the ceramic seat. The micromirror device is electrically connected to the circuit board through a plurality of wires. In the '853 patent, the mounting seat is only adhered to the circuit board without any pre-positioning design, so the mounting seat and the circuit board have to be aligned precisely.
FIG. 1 shows another assembled structure of a mounting seat and a circuit board according to the prior art. As shown in FIG. 1, two opposite positioning pins 12 are formed on a mounting seat 10. The positioning pins 12 and the mounting seat 10 are integrally formed. Two positioning holes 16 of a circuit board 14 correspond to the two positioning pins 12. The circuit board 14 can be positioned firmly by combining the positioning pins 12 with the positioning holes 16.
As shown in FIG. 2, the positioning pin 12 has a small outer diameter and cannot be easily formed by way of powder metallurgy. So, a shaft having a larger outer diameter is firstly formed, and then the shaft is cut or milled to remove a portion of the outer circumference 18 (indicated by dashed lines) of the shaft so that a pin having a smaller radius is obtained. The method of forming the positioning pin 12 is very inconvenient and requires a longer period of time to finish the cutting and milling processes. So, it is disadvantageous to the mass production. Meanwhile, the manufacturing cost is high because the extra machining procedures are needed.
The positioning pins 12 of the mounting seat 10 and the circuit board 14 are simply positioned. Thus, it is unnecessary to form the positioning pins 12 with the high-precision powder metallurgy method and the cutting or milling processes. In other words, modifying the method of forming the positioning pins and the structure configuration under the condition of the positioning requirement is advantageous to the improvement of the difficulty in manufacturing the mounting seat and the elimination of the drawback of the high cost.

SUMMARY OF THE INVENTION

According to the above-described prior art, the base and the positioning pins of the prior art mounting seat are integrally formed by the same material, so the mounting seat cannot be manufactured easily and has a high cost. Therefore, the invention provides a new mounting seat to solve the prior art problems.
An object of the invention is to provide a method of manufacturing a mounting seat for an IC and a circuit board. The method includes the steps of: forming a base by way of powder metallurgy and forming two pin holes on the base; and placing the base in a mold and forming two positioning pins protruding beyond a surface of the base in the pin holes by way of insert molding. The positioning pins may be made of a plastic material or a Bakelite material, so the pins may have smaller outer diameters. Thus, the mounting seat does not need the prior art cutting or milling processes, and thus can be manufactured more easily with the lower manufacturing cost.
Another object of the invention is to provide a method of manufacturing a mounting seat for an IC and a circuit board. The method includes the steps of: forming a base by way of powder metallurgy and forming two pin holes on the base; forming two positioning pins separated from the base by way of injection molding; and assembling the positioning pins with the base by inserting the positioning pins into the pin holes respectively, wherein one end of each of the positioning pins protrudes beyond a surface of the base. The positioning pins may be made of a plastic material or a Bakelite material, so the pins may have smaller outer diameters. Thus, the mounting seat does not need the prior art cutting or milling processes, and thus can be manufactured more easily with the lower manufacturing cost.
Still another object of the invention is to provide a mounting seat for an IC and a circuit board. The mounting seat includes a base, two pin holes formed on the base and at two opposite ends of the base, and two positioning pins each having a first end and a second end. The first ends of the positioning pins are fixed into the two pin holes, respectively, and the second ends of the positioning pins protrude beyond a surface of the base. Thus, the inconvenience of machining the positioning pins can be eliminated, and the manufacturing cost can be greatly reduced.
Other objects, features, and advantages of the invention will become apparent from the following detailed description of the preferred but non-limiting embodiments. The following description is made with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded view showing a mounting seat and a circuit board according to the prior art.

FIG. 2 shows the exterior of the conventional positioning pin before and after it is machined.

FIG. 3 shows the exterior of a base according to the invention.

FIG. 4 is a schematic illustration showing a positioning pin manufactured by way of insert molding according to the invention.

FIG. 5 is an exploded view showing the positioning pin and the base which are assembled together according to the invention.

FIG. 6 is a schematic illustration showing an assembled structure of the positioning pin and the base according to the invention.

FIG. 7 is a block diagram showing a manufacturing method according to the invention.

FIG. 8 is a block diagram showing another manufacturing method according to the invention.

FIG. 9 is an exploded view showing the mounting seat and the circuit board according to the invention.

FIG. 10 is a schematic illustration showing an assembly of the mounting seat, the circuit board and an IC device according to the invention.

FIG. 11 partially shows the exterior of the mounting seat according to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

FIG. 3 shows a base 22 of a mounting seat 20. The base 22 is made by way of powder metallurgy. A surface of the base 22 is formed with two pin holes 23 and an accommodating opening 24. A heat sink 26 is disposed on the surface of the base 22. The two pin holes 23 are disposed at opposite ends. The accommodating opening 24 is formed at a middle position of the base 22, and the heat sink 26 crosses over two sides of the accommodating opening 24 and protrudes beyond the surface of the base 22.
As shown in FIG. 4, the base 22 is placed in an injection molding mold 90, and a positioning pin 30 is formed in each pin hole 23 by way of molding. Thus, the positioning pin 30 and the base 22 are combined together.
It is to be noted that the positioning pin 30 is formed in the pin hole 23 by way of insert molding. The positioning pin 30 may be formed of, without limitation to, a plastic material or a Bakelite material.
As shown in FIG. 5, the base 22 of the mounting seat 20 is formed by way of powder metallurgy. The surface of the base 22 is formed with two pin holes 23 and one accommodating opening 24, and a heat sink 26 is disposed on the surface of the base. The two pin holes 23 are disposed at two opposite ends. The accommodating opening 24 is formed at a middle position of the base 22. The heat sink 26 crosses over two sides of the accommodating opening 24 and protrudes beyond the surface of the base 22. Also, two positioning pins 40 may be formed by any method, such as injection molding, and the material thereof may be the plastic material or the Bakelite material.
As shown in FIGS. 5 and 6, the two positioning pins 40 corresponding to the pin holes 23 are inserted into and fixed to the pin holes 23, respectively. Consequently, the positioning pins 40 and the base 22 are combined together. The process of combining the positioning pins 40 with the base 22 may be performed by an automating apparatus.
As shown in FIG. 7, the method of the invention includes steps 52 and 54.
In step 52, the base having two pin holes is formed by way of powder metallurgy.
In step 54, the base is placed in an injection molding mold, and the positioning pin, which protrudes beyond the surface of the base, is formed in each pin hole by way of insert molding.
After steps 52 and 54 are finished, the mounting seat may be taken out and used.
As shown in FIG. 8, another method of the invention includes steps 52, 56 and 58.
In step 52, the base having two pin holes is formed by way of powder metallurgy.
In step 56, the positioning pins are formed by way of any molding technology (e.g., by way of injection molding technology).
In step 58, the positioning pins are assembled into and adhered to the pin holes of the base. The assembling process may be performed quickly by an automating apparatus.
In the above-mentioned manufacturing methods of the invention, either the method of forming the positioning pin 30 in the pin hole 23 by way of insert molding technology or the method of inserting and assembling the separately formed positioning pins 40 into the pin holes 23 can quickly finish the manufacturing procedures without additional machining procedures. Thus, the manufacturing cost can be effectively reduced.
As shown in FIG. 9, the mounting seat 20 mentioned hereinabove includes a base 22, two pin hole 23 and one accommodating opening 24 formed on the surface of the base 22, and one heat sink 26 disposed on the surface of the base 22. The two pin holes 23 are formed at two opposite ends. The accommodating opening 24 is formed at a middle position of the base 22, and the heat sink 26 crosses over two sides of the accommodating opening 24 and protrudes beyond the surface of the base 22. As shown in FIGS. 9 and 11, two positioning pins 30 are assembled in the pin holes 23, and the edge of the positioning pin 30 is formed with a ring-shaped guiding slant 32.
As shown in FIGS. 9 and 10, when a circuit board 60 is to be disposed on the mounting seat 20, positioning holes 62 of the circuit board 60 correspond to the positioning pins 30, respectively. The circuit board 60 and the positioning pin 30 can be easily combined together under the guiding of the guiding slant 32 with respect to the positioning hole 62. The circuit board 60 is placed on the surface of the base 22 and the effects of adhering and positioning can be achieved.
Also, an IC (or a MEMS device) 70 is disposed in the accommodating opening 24, a surface of the IC 70 contacts the heat sink 26, which is advantageous to the heat dissipation. Consequently, the structure of the invention enables the IC 70 and the circuit board 60 to be assembled and positioned on the mounting seat 20 easily, and also enhances the heat dissipation efficiency.
While the preferred embodiment of the present invention has been shown and described, it will be apparent to those skilled in the art that various modifications may be made in the embodiment without departing from the spirit of the present invention. Such modifications are all within the scope of the present invention.

Claims

1. A method of manufacturing a mounting seat for an integrated circuit (IC) and a circuit board, the method comprising the steps of:

forming a base by way of powder metallurgy and forming two pin holes on the base; and

placing the base in a mold and forming two positioning pins protruding beyond a surface of the base in the pin holes by way of injection molding.

2. The method according to claim 1, wherein the positioning pins are formed by way of insert molding.

3. The method according to claim 1, wherein the positioning pins are made of a plastic material or a Bakelite material.

4. A method of manufacturing a mounting seat for an integrated circuit (IC) and a circuit board, the method comprising the steps of:

forming a base by way of powder metallurgy and forming two pin holes on the base;

forming two positioning pins separated from the base by way of injection molding; and

assembling the positioning pins with the base by inserting the positioning pins into the pin holes respectively, wherein one end of each of the positioning pins protrudes beyond a surface of the base.

5. The method according to claim 4, wherein the positioning pins are made of a plastic material or a Bakelite material.

6. A mounting seat for an integrated circuit (IC) and a circuit board, the mounting seat comprising:

a base;

two pin holes formed on the base and at two opposite ends of the base; and

two positioning pins each having a first end and a second end, wherein the first ends of the positioning pins are fixed into the two pin holes, respectively, and the second ends of the positioning pins protrude beyond a surface of the base.

7. The mounting seat according to claim 6, wherein the pin holes penetrate through the mounting seat.

8. The mounting seat according to claim 6, wherein the second end of the positioning pin is formed with a guiding slant at a circumference of the positioning pin.

9. The mounting seat according to claim 6, wherein the positioning pin is adhered to the pin hole.

10. The mounting seat according to claim 6, wherein the positioning pin is fixed into the pin hole by way of insert molding.

11. The mounting seat according to claim 6, wherein the surface of the base is formed with an accommodating opening for accommodating the IC.

12. The mounting seat according to claim 6, wherein a protruding heat sink is disposed on the surface of the base.

13. The mounting seat according to claim 6, wherein the surface of the base is formed with an accommodating opening and a heat sink is disposed on the surface of the base, and the heat sink crosses over two sides of the accommodating opening and protrudes beyond the surface of the base.