TEST FIXTURE FOR PROBE APPLICATION

• US 20150070037A1
• Filed: 08/04/2014
• Published: 03/12/2015
• Est. Priority Date: 09/09/2013
• Status: Abandoned Application

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Hotelling, Steven P., Pragada, Anuranjini, Van Ausdall, Terrence L.
• Application Number:
  US14/450,714
• Publication Number:
  US 20150070037A1
• Time in Patent Office: Days
• US Class Current: 324/754.03
• CPC Class Codes: G01D 18/00 Testing or calibrating apparatus or arrangements provided for in groups G01D1/00 - G01D15/00
• CPC Class Codes: G01D 2218/10 Testing of sensors or measuring arrangements
• CPC Class Codes: G01D 5/24 by varying capacitance
• CPC Class Codes: G01R 1/0408 Test fixtures or contact fields; Connectors or connecting adaptors; Test clips; Test sockets G01R1/067 takes precedence; mass production testing systems G01R31/59; testing of connections G01R31/66; for testing printed circuit boards G01R31/2808
• CPC Class Codes: G01R 1/06705 Apparatus for holding or moving single probes for moving multiple probe heads or ICs under test G01R31/2886
• CPC Class Codes: G01R 31/2829 Testing of circuits in sensor or actuator systems testing of apparatus for measuring electric or magnetic variables G01R35/00; testing of indicating or recording apparatus G01D; in airbag systems B60R21/0173; checking gas analysers G01N33/007; monitoring or fail-safe circuits for electromagnets H01F7/1844
• CPC Class Codes: G06V 40/13 Sensors therefor

Abstract

Systems and methods to fixture and utilizing a probe which tests a capacitive array are described herein. A support bracket with freedom about a plurality of axes may aid in locating a probe and allowing the probe to contact multiple surfaces consistently. By utilizing the support bracket, the angle between a test probe and a contact surface may be minimized such that the surface of the test probe and the contact surface may rest flat against one another. The system may also limit the force translated through support bracket. This system and method may allow for a high degree of accuracy and a high degree of precision during contact of the test probe and the test surface.

Claims

1. A probe apparatus comprising:

a housing;

a probe having a contact surface that extends below the bottom surface of the housing and operably attached to the housing;

a support bracket having freedom about at least two axes and connected to the probe;

wherein

the probe is operable to move freely about at the least two axes to adapt to a misalignment of the contact surface with another surface.

2. The apparatus of claim 1, wherein the support bracket connects the probe to the housing.

3. The apparatus of claim 2, wherein the support bracket includes an inner structure that is attached to the probe.

4. The apparatus of claim 3, wherein the support bracket includes an outer structure connected to the inner structure by a first connection along a first axis.

5. The apparatus of claim 4, wherein the support bracket includes a second connection which connects the ouster structure to the housing along a second axis that is 90 degrees offset from the first connection.

6. The apparatus of claim 5, wherein the connection along the first axis and the second axis is a hinge.

7. The apparatus of claim 5, wherein the connection along the first axis and the second axis is a is a strip of sheet metal.

8. The apparatus of claim 2, wherein the support bracket includes four separate strips of sheet metal that are sufficiently flexible to allow the probe to separately flex each of the four separate strips of metal giving the probe freedom about at least 2 axes.

9. The apparatus of claim 2, wherein the support bracket is a gel which surrounds and supports the probe connecting the probe to the housing.

10. A test fixture comprising:

an arm having an upper spring plate and a lower spring plate operable to maintain an un-fixed end of the arm in a substantially vertical orientation;

a probe housing attached to the bottom surface of the arm;

a probe located within the probe housing, the probe having a contact surface that extends from the housing and is operable to contact a flat surface; and

a support bracket having freedom about at least two axes and connecting the probe to the housing;

wherein

the probe is operable to move freely about the at least two axes.

11. The test fixture of claim 10, further comprising a camera located with the probe housing.

12. The test fixture of claim 10, further comprising a second probe located in the probe housing.

13. The test fixture of claim 10, wherein the support bracket comprises a gimbal structure comprising:

an inner support structure;

an outer support structure; and

a plurality of flexible connectors between the inner and outer support structures, the plurality of flexible connectors permitting motion of the inner support structure with respect to the outer support structure.

14. The test fixture of claim 10, wherein the arm comprises:

a first and a second non-conductive block sandwiched between the upper spring plate and the lower spring plate;

wherein

the two non-conductive blocks are separated with each one located at the ends of the spring plate; and

the spring plate is operative to flex vertically while maintaining the blocks in a substantially vertical alignment.

15. The test fixture of claim 14, further comprising:

a base support connected to one of the two non-conductive blocks opposite the end of the arm connected to the probe housing;

wherein

the base support is operable to move the arm along a z axis; and

the base support is operable to move the entire test fixture in the x and y directions.

16. A method for testing a capacitive array comprising:

lowering a first probe toward a test platform;

contacting the test platform with a contact surface of the first probe;

determining if the first probe is in angular alignment with the test platform;

if not, repositioning the contact surface of the first probe relative to a surface of test platform; and

taking a first measurement from the probe based on the first probe'"'"'s capacitive profile.

17. The method of claim 16 further comprising:

positioning a target associated with the test platform;

locating the target with a video camera that is a apart of an apparatus holding the first probe;

moving the apparatus holding the first probe based on feedback from the video camera; and

aligning the first probe with the test platform based on position of the target.

18. The method of claim 16 further comprising:

overdriving the first probe into test platform causing an arm, that is a part of the apparatus holding the first probe, to deflect and forcing the first probe against the test platform based on the deflection caused by the arm.

19. The method of claim 16 further comprising:

hacking the first probe away from the test platform.

20. The method of claim 16 further comprising:

repeating the process with a second probe that is a part of the apparatus holding the first probe.