GB2138631A

GB2138631A - Heat sinks

Info

Publication number: GB2138631A
Application number: GB08323625A
Authority: GB
Inventors: Marvin Michael Cohen; Francis Leland Payne
Original assignee: Burr Brown Research Corp
Current assignee: Burr Brown Research Corp
Priority date: 1982-12-20
Filing date: 1983-09-02
Publication date: 1984-10-24
Also published as: GB8323625D0; DE3346017A1; GB2138631B; JPS59119380A; FR2538167B1; FR2538167A1

Abstract

To dissipate heat generated by an alphanumeric display (10) which is mounted on a circuit board (14) a heat sink (18) is coupled to the underside of the alphanumeric display (10). The heat sink (18) has at least one transfer member (18b) which extends through the circuit board (14 )and is coupled to a dissipation plate (28). The dissipation plate (28) is exposed to an environment which is removed from the immediate environment of the electronic circuit board (14). Heat generated by the alphanumeric display (10) is transferred to the heat sink (18) and through the transfer member(s) (18b) to the dissipation plate (28). <IMAGE>

Description

SPECIFICATION Heat sink and method for dissipating heat generated by electronic displays This invention relates generally to heat sinks, and more specifically, to a heat sink and method utilized in conjunction with an alphanumeric display to transfer heat generated by the display through a heat sink to a dissipation plate which is exposed to the exterior of a circuit housing.

Alphanumeric displays are utilized in many electronic circuits to convey outputs provided by the circuits. Unfortunately, alphanumeric displays commonly generate a large amount of heat. In many situations, circuit performance is very dependent on the temperature of the environment in which the circuit operates. As the temperature of the environment increases, sensitive components of the circuit may exhibit altered performance and negatively affect the reliability of the circuit.

Since alphanumeric displays are often a major source of heat to the immediate environment in which a circuit operates, the need exists to provide a heat sink and method for effectively transferring heat generated by the alphanumeric display from the immediate environment of the circuit to an atmosphere or environment which is removed from that of the circuit.

It is an object of the present invention to provide a heat sink which efficiently transfers heat generated by an alphanumeric display to an environment removed from the immediate environment of the circuit. Thus, the circuit performance will not be affected by increased temperature in the immediate circuit environment.

The invention provides an article for dissipating heat, comprising a heat generating alphanumeric display which is mounted on an electronic circuit board; a heat sink coupled to the underside of the alphanumeric display, a portion of the heat sink extending through the circuit board; and a dissipation plate coupled to the portion of the heat sink which extends through the electronic circuit board, the heat sink transferring heat generated by the alphanumeric display to the dissipation plate.

The invention also provides an article for dissipating heat comprising a heat generating display mounted on an electronic circuit board; heat sink means coupled to the underside of the display for conducting heat generated by the display, the heat sink means having a portion extending through the circuit board; and heat dissipation means coupled to the portion of the heat sink means which extend through the circuit board for dissipating heat transferred to the heat dissipation means by the heat sink means.

The invention further provides a method for dissipating heat generated by an electronic display mounted on an electronic circuit board comprising locating a heat sink between the display and a non-conductive surface of the electronic circuit board; and transferring heat generated by the display through the heat sink to the dissipation plate.

The invention will be described further, by way of example, with reference to the accompanying drawings, wherein Figure 1 is a sectional-vertical view of an alphanumeric display coupled to a preferred heat sink of the invention and mounted to an electronic circuit board; Figure 2 is a sectional-vertical view of the alphanumeric display and heat sink of Figure 1 taken along lines 2-2 of Figure 1; and Figure 3 is a top-horizontal view of the alphanumeric display and heat sink of Figure 1 and Figure 2.

Referring to the Figures, an alphanumeric display, referenced generally by the numeral 10, comprises four individual display units 12a, 12b, 1 2c and 12d. The alphanumeric display 10 receives signals from an electronic circuit board 14 through multiple lead frame pins 16. In the past, the alphanumeric display 10 was simply mounted directly to the non-conductive surface 14a of the electronic circuit board 14, and the lead frame pins 16 soldered at the conductive side 14b of the electronic circuit board 14. When the alphanumeric display 10 was activated, heat was transferred from the back side of the alphanumeric display 10 to the electronic circuit board 14.As e result, performance of electronic components (not shown) mounted on the electronic circuit board 14 were adversely affected by the temperature increase of their immediate environment.

To alleviate this problem, a heat sink 18 is coupled to the underside of the alphanumeric display 10. The heat sink 18 comprises a rectangular horizontal member 18a which has a planar top face 20 and a planar bottom face 22.

The planar top face 20 is thermally coupled to the underside of the alphanumeric display 10. The planar bottom face 22 is mounted to the nonconductive surface 14a of the electronic circuit board 14. A layer of conductive material 24 may be placed between the top planar face 20 of the horizontal member 1 8a and the underside of the alphanumeric display 10 to enhance heat transfer to the horizontal member 18a. The alphanumeric display 10 is pressed flush against the top planar face 20 of the horizontal member 18a, or if a conductive layer 24 is applied to the top planar face 20, the alphanumeric display 10 is placed flush against the conductive layer 24. The multiple lead frame pins 16 are then soldered to the conductive surface 14b of the electronic circuit board 14.In this manner, the alphanumeric display 10 is held tightly against the heat sink 18 to assure efficient thermal transfer.

The heat sink 18 further comprises at least one, and preferably two vertical transfer members 18b.

The vertical transfer members 18b extend from the rectangular member 18a through holes 26 in the electronic circuit board 14, and are coupled to a a dissipation plate 28. The dissipation plate 28 is exposed to an environment 30 which is removed from the electronic circuit board 14. The vertical transfer members 18b are tapped to receive recessed screws 32, thereby holding the dissipation plate tightly to the vertical transfer members 18b. The dissipation plate could effectively serve as the back plate of a case for the circuit (not shown).

In operation, the alphanumeric display 10, comprised of individual displays 12a,12b,12c and 12d, receives signals from the electronic circuit board 14, and simultaneously generates heat when activated. The heat is transferred through the conductive layer 24 to the horizontal member 1 8a of the heat sink 18. The heat is then transferred through the vertical transfer members 18b to the dissipation plate 28, where it is dissipated in the removed environment 30. Thus, electronic components mounted to the electronic circuit board 14 are not affected by an increased temperature in the immediate environment due to heat generated by the alphanumeric display.

While the invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that the foregoing and other changes in form and details may be made therein without departing from the spirit and scope of the invention.

Claims

1. An article for dissipating heat, comprising a heat generating alphanumeric display which is mounted on an electronic circuit board; a heat sink coupled to the underside of the alphanumeric display, a portion of the heat sink extending through the circuit board; and a dissipation plate coupled to the portion of the heat sink which extends through the electronic circuit board, the heat sink transferring heat generated by the alphanumeric display to the dissipation plate.

2. An article as claimed in Claim 1, wherein the dissipation plate is exposed to an environment removed from the electronic circuit board, the dissipation plate dissipating heat transferred by the heat sink in the removed environment.

3. An article as claimed in Claim 1, further comprising a layer of conductive material coupled between the heat sink and the underside of the alphanumeric display, the layer of conductive material enhancing the transfer of heat from the alphanumeric display to the heat sink.

4. An article as claimed in Claim 1, wherein the heat sink comprises a rectangular horizontal member having a planar top face which is thermally coupled to the underside of the alphanumeric display, and having a planar bottom face which is mounted on a non-conductive surface of the electronic circuit board; and at least one vertical transfer member extending through the electronic circuit board and coupled to the dissipation plate, the vertical transfer member transferring heat generated by the alphanumeric display from the horizontal member to the dissipation plate.

5. An article as claimed in Claim 1, wherein the heat sink is of aluminum.

6. An article for dissipating heat comprising a heat generating display mounted on an electronic circuit board; heat sink means coupled to the underside of the display for conducting heat generated by the display, the heat sink means having a portion extending through the circuit board; and heat dissipation means coupled to the portion of the heat sink means which extend through the circuit board for dissipating heat transferred to the heat dissipation means by the heat sink means.

7. An article as claimed in Claim 6, further comprising conductive means coupled between the heat sink means and the display for enhancing the transfer of heat from the display to the heat sink means.

8. A method for dissipating heat generated by an electronic display mounted on an electronic circuit board comprising locating a heat sink between the display and a non-conductive surface of the electronic circuit board; and transferring heat generated by the display through the heat sink to the dissipation plate.

9. A method as claimed in Claim 8, wherein the step of transferring heat generated by the display to a dissipation plate comprises absorbing heat generated by the display with the heat sink, and conducting the heat through the heat sink to the dissipation plate.

10. A method as claimed in Claim 9, further comprising dissipating the heat conducted to the dissipation plate by the heat sink in an environment removed from that of the display.

11. A method as claimed in Claim 8, wherein the step of locating a heat sink between the display and the non-conductive surface of the circuit board comprises mounting the heat sink to the non-conductive surface of the circuit board; extending a portion of the heat sink through the circuit board; positioning the display on the heat sink; and soldering leads of the display to a conductive surface of the circuit board to tightly hold the display in thermal communication with the heat sink.

12. A method as claimed in Claim 8, wherein the step of locating the heat sink between the display and the non-conductive surface of the circuit board comprises mounting the heat sink to the non-conductive surface of the circuit board; extending a portion of the heat sink through the circuit board; placing a layer of conductive material on the top surface of the heat sink, positioning the display on the layer of conductive material placed on the heat sink; and soldering leads of the display to a conductive surface of the circuit board to couple the display tightly to the conductive layer placed on the heat sink and to tightly mount the heat sink to the non-conductive surface of the circuit board.

13. An article for dissipating heat substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

14. A method of dissipating heat from an electronic component substantially as hereinbefore described.