Mitigation of block bending in a ring laser gyroscope caused by thermal expansion or compression of a circuit board

• US 8,901,432 B2
• Filed: 09/30/2011
• Issued: 12/02/2014
• Est. Priority Date: 09/30/2011
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Clark, Matthew, Galbrecht, Craig A., Goblish, George, Koshiol, Myles
• Primary Examiner(s): Nguyen, Hoa C
• Assistant Examiner(s): PATEL, AMOL H
• Application Number:
  US13/250,503
• Publication Number:
  US 20130081860A1
• Time in Patent Office: 1,159 Days
• Field of Search: 174/250, 174/254, 174/261, 174/260, 361/748, 361/749, 361/760, 361/767, 361/768
• US Class Current: 174/260
• CPC Class Codes: H05K 1/0271 Arrangements for reducing stress or warp in rigid printed circuit boards, e.g. caused by loads, vibrations or differences in thermal expansion
• CPC Class Codes: H05K 2201/068 wherein the coefficient of thermal expansion is important
• CPC Class Codes: H05K 2201/09027 Non-rectangular flat PCB, e.g. circular
• CPC Class Codes: H05K 2201/09063 Holes or slots in insulating substrate not used for electrical connections
• CPC Class Codes: H05K 2201/09854 Hole or via having special cross-section, e.g. elliptical
• CPC Class Codes: Y10T 29/49124 On flat or curved insulated base, e.g., printed circuit, etc.

Abstract

An apparatus includes a sheet of circuit board material, at least one electrically conductive trace positioned on the sheet of circuit board material, and at least one electrically conductive contact pad positioned on the sheet of circuit board material and coupled to the at least one electrically conductive trace. The apparatus further includes at least one deformation point configured to absorb stresses developed in the sheet of circuit board material when the sheet of circuit board material experiences resistance to expansion or compression caused by connection to an object resisting expansion or compression.

Claims

1. An apparatus comprising:

a sheet of circuit board material;

at least one electrically conductive trace positioned on the sheet of circuit board material;

at least one electrically conductive contact pad positioned on the sheet of circuit board material and coupled to the at least one electrically conductive trace;

a first connection point configured to connect the sheet of circuit board material to an object resisting expansion or compression;

a second connection point configured to connect the sheet of circuit board material to the object resisting expansion or compression; and

at least one deformation point positioned between the first connection point and the second connection point and configured to absorb stresses developed in the sheet of circuit board material when the sheet of circuit board material experiences resistance to expansion or compression caused by connection to the object resisting expansion or compression at the first connection point and the second connection point, wherein the absorption of stresses developed in the sheet of circuit board material minimizes the transfer of the stresses to the object resisting expansion or compression.

2. The apparatus of claim 1, wherein the sheet of circuit board material is created using at least one of flexible printed circuit board, rigid printed circuit board, and a combination of flexible printed circuit board and rigid printed circuit board.

3. The apparatus of claim 1, wherein the at least one deformation point is created by removing circuit board material from the sheet of circuit board material to reduce a cross-sectional area of the sheet of circuit board material at a first location on the sheet circuit board material.

4. The apparatus of claim 3, wherein the removed circuit board material has a circular shape.

5. The apparatus of claim 1, wherein the circuit board material includes a plurality of cutouts, each configured to create at least one deformation point in at least one location between a first section and a second section of the sheet of circuit board material, wherein each deformation point absorbs stresses developed between the first section and the second section of the sheet of circuit board material.

6. The apparatus of claim 5, wherein the plurality of cutouts are arranged on the surface of the sheet of circuit board material in a symmetric pattern.

7. The apparatus of claim 1, further comprising:

a substrate with a top surface, wherein the object resisting expansion or compression is the substrate;

adhesive material attaching the top surface of the substrate with a bottom surface of the sheet of circuit board material; and

wherein the adhesive material inhibits the transfer of stresses generated in the sheet of circuit board material when the sheet of circuit board material expands or contracts at a different rate from the substrate to which the sheet of circuit board material is attached.

8. The apparatus of claim 1, wherein the adhesive material has consistent stress transfer properties across an operating temperature range.

9. An apparatus comprising:

an object resisting expansion or compression, the object having a top surface and a first coefficient of thermal expansion;

a circuit board having a bottom surface and a second coefficient of thermal expansion that is different than the first coefficient of thermal expansion of the object;

a first connection point configured to connect the sheet of circuit board material to the object resisting expansion or compression;

a second connection point configured to connect the sheet of circuit board material to the object resisting expansion or compression; and

adhesive material bonding the bottom surface of the circuit board to the top surface of the object at the first connection point and the second connection point, wherein the adhesive material is configured to inhibit the transfer of stresses generated in the circuit board when the circuit board experiences resistance to expansion or compression caused by connection to the object resisting expansion or compression.

10. The apparatus of claim 9, wherein the object is a laser block.

11. The apparatus of claim 9, wherein the circuit board is formed from a sheet of circuit board material;

and

wherein the circuit board includes at least one electrically conductive trace positioned on a top surface.

12. The apparatus of claim 9, wherein the second coefficient of thermal expansion of the circuit board is greater than the first coefficient of thermal expansion of the object.

13. The apparatus of claim 9, wherein the adhesive material has consistent stress transfer properties across an operating temperature range.

14. The apparatus of claim 9, wherein the circuit board includes at least one deformation point configured to absorb stresses developed in the circuit board when the circuit board experiences resistance to expansion or compression caused by the bond between the circuit board and the object through the adhesive material.

15. The apparatus of claim 14, wherein the at least one deformation point is created by removing circuit board material to reduce the cross-sectional area of the circuit board at a first location on the circuit board.

16. The apparatus of claim 14, wherein the circuit board includes a plurality of cutouts, each configured to create at least one deformation point in at least one location between a first section and a second section of the circuit board, wherein each deformation point absorbs stresses developed between the first section and the second section of the circuit board material.

17. A method comprising:

fabricating a sheet of circuit board material with at least one deformation point between a first section and a second section of the sheet of circuit board material, the first section of the sheet of circuit board material having a first connection point and the second section of the sheet of circuit board material having a second connection point;

fabricating at least one electrically conductive trace on the sheet of circuit board material;

fabricating at least one electrically conductive contact pad positioned on the sheet of circuit board material and coupled to the at least one electrically conductive trace; and

wherein the at least one deformation point absorbs stresses developed in the sheet of circuit board material when the sheet of circuit board material experiences resistance to expansion or compression caused by connection to an object resisting expansion or compression at the first connection point and the second connection point, wherein the absorption of stresses developed in the sheet of circuit board material minimizes the transfer of the stresses to the object resisting expansion or compression.

18. The method of claim 17, further comprising:

mounting a bottom surface of the sheet of circuit board material to a top surface of a substrate using an adhesive; and

wherein the adhesive material is configured to inhibit the transfer of stresses generated in the sheet of circuit board material when the sheet of circuit board material expands or contracts at the different rate than the object.

19. An apparatus comprising:

a circuit board having a bottom surface and at least one deformation point between a first section and a second section of the sheet of circuit board, the first section of the circuit board having a first connection point and the second section of the circuit board having a second connection point;

an object having a top surface;

adhesive material attaching the bottom surface of the circuit board to the top surface of the object;

wherein the at least one deformation point absorbs stresses developed in the sheet of circuit board material when the sheet of circuit board material experiences resistance to expansion or compression caused by connection to an object resisting expansion or compression at the first connection point and the second connection point, wherein the absorption of stresses developed in the circuit board minimizes the transfer of the stresses to the object resisting expansion or compression; and

wherein the adhesive material inhibits transfer of stresses from the circuit board to the object.

20. The apparatus of claim 19, wherein the circuit board is a flexible printed circuit board.