Low travel dome and systems for using the same

• US 9,449,769 B2
• Filed: 10/29/2013
• Issued: 09/20/2016
• Est. Priority Date: 10/30/2012
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Leong, Craig C., Niu, James J., Brock, John M., Hendren, Keith J., Wilson, Thomas W. Jr.
• Primary Examiner(s): Leon, Edwin A.
• Application Number:
  US14/066,197
• Publication Number:
  US 20140116867A1
• Time in Patent Office: 1,057 Days
• Field of Search: 200512-514, 200/5.A, 200/521, 200/341
• US Class Current: 1/1
• CPC Class Codes: H01H 13/14 Operating parts, e.g. push-button
• CPC Class Codes: H01H 13/85 characterised by tactile feedback features
• CPC Class Codes: H01H 2215/006 Only mechanical function
• CPC Class Codes: H01H 2215/02 Reversed domes

Abstract

A low travel switch and systems for using the same. A low travel switch may include a key cap and an elastomeric dome configured to provide a predefined tactile feedback over a predefined travel distance of the key cap when the key cap is depressed by a user.

Claims

1. An elastomeric dome for use with a key, the elastomeric dome comprising:

a lower portion;

an upper portion; and

a wall that spans from the lower portion to the upper portion, each of the wall, the lower portion, and the upper portion comprising;

a physical property comprising one of a thickness or a diameter, and the elastomeric dome being tuned to provide predefined tactile feedback over a predetermined travel amount of the key based on a predefined ratio between one of the physical properties and another one of the physical properties.

2. The elastomeric dome of claim 1, wherein the physical property of the wall is a wall thickness.

3. The elastomeric dome of claim 2, wherein the physical property of the lower portion is an outer diameter.

4. The elastomeric dome of claim 3, wherein the physical property of the upper portion is an upper diameter.

5. The elastomeric dome of claim 1, wherein the wall forms an angle with respect to the lower portion.

6. The elastomeric dome of claim 1, wherein the elastomeric dome is tuned to provide the predefined tactile feedback over the predetermined travel amount based on a predefined ratio between the angle and another one of the physical properties.

7. The elastomeric dome of claim 1, wherein the predefined tactile feedback is determined from a predefined force-displacement curve characteristic.

8. An elastomeric dome for use with a key in a keyboard, the elastomeric dome comprising:

a footprint;

a roof portion having a predetermined diameter; and

a wall of a predetermined thickness that connects the roof portion to the footprint wherein;

a ratio between the predetermined thickness and the predetermined diameter is less than 0.10; and

the elastomeric dome is operative to enable a keystroke of the key to undergo an abrupt force change when the keystroke is 1.25 millimeters or less.

9. The elastomeric dome of claim 8, wherein a hollow cavity exist within an internal surface of the wall.

10. The elastomeric dome of claim 8 further comprising:

a nub disposed opposite the roof portion.

11. The elastomeric dome of claim 8, wherein the predetermined thickness is in a range from 0.19 millimeters to 0.24 millimeters.

12. The elastomeric dome of claim 8, wherein the predetermined diameter is in a range from 3.16 millimeters to 3.19 millimeters.

13. The elastomeric dome of claim 8, wherein the footprint comprises an outer diameter that is greater than the predetermined diameter.

14. The elastomeric dome of claim 13, wherein the outer diameter is in a range from 5.6 millimeters to 6 millimeters.

15. The elastomeric dome of claim 8, wherein:

the footprint is operative to reside over a planar surface; and

the wall is disposed at a predetermined angle from the planar surface.

16. The elastomeric dome of claim 15, wherein the predetermined angle is one of 50 degrees and 51 degrees.

17. The elastomeric dome of claim 16, wherein the elastomeric dome comprises material having a predefined durometer.

18. The elastomeric dome of claim 8, wherein the abrupt force change provides a predefined tactile feedback to a user when the user depresses the key.

19. The elastomeric dome of claim 8, wherein the abrupt force change is based on a peak force and a draw force associated with the elastomeric dome.

20. A switch assembly comprising:

a key cap; and

a hemispherical structure residing beneath the key cap and comprising;

an upper portion;

a lower portion having an outer diameter; and

a domed surface extending from the upper portion to the lower portion, the domed surface having a predefined thickness;

wherein;

a ratio between the predetermined thickness and the outer diameter is less than or equal to 0.04; and

the hemispherical structure is operative control movement of the key cap according to a predetermined force-displacement curve characteristic when the movement is less than a predetermined amount.

21. The switch assembly of claim 20, wherein the predetermined amount is one of less than and equal to 1.25 millimeters.

22. The switch assembly of claim 20, wherein the domed surface comprises a predefined height from the lower portion to the upper portion.

23. The switch assembly of claim 22, wherein a ratio between the predetermined thickness and the predefined height is one of less than and equal to 0.12.

24. The switch assembly of claim 20, wherein the predefined force-displacement curve characteristic comprises a variation in a force required to move the upper portion over a range of predefined distances.

25. The switch assembly of claim 20, wherein the predefined force-displacement curve characteristic comprises a variation in a force required to move the key cap over a range of predefined distances.

26. The switch assembly of claim 20, wherein the hemispherical structure comprises material having a predefined durometer.

27. An apparatus for use with a key of a keyboard, the apparatus comprising:

an inner dome at least partially defining a top surface of the apparatus; and

an outer dome at least surrounding the inner dome;

wherein;

the inner dome defines a first opening that faces a first direction opposite the top surface; and

the outer dome defines a second opening that faces a direction opposite the first direction.

28. The apparatus of claim 27, wherein the inner dome and the outer dome share a common footprint.

29. The apparatus of claim 28, wherein the inner dome comprises a roof portion and an inner hemispherical surface that extends from the roof portion to the footprint.

30. The apparatus of claim 29, wherein a diameter of the roof portion is less than a diameter of the footprint.

31. The apparatus of claim 28, wherein the outer dome comprises an upper rim portion and an outer hemispherical surface that extends from the upper rim portion to the footprint.

32. The apparatus of claim 31, wherein a diameter of the upper rim portion is greater than a diameter of the footprint.

33. The apparatus of claim 27, wherein the first direction is opposite a direction of a keystroke of the key.

34. The apparatus of claim 27, wherein a thickness of the inner dome is the same as the thickness of the outer dome.

35. The apparatus of claim 27, wherein a combination of the inner dome and the outer dome is operative to provide predefined tactile feedback in response to a keystroke of the key.

36. The apparatus of claim 27, wherein a combination of the inner dome and the outer dome is operative to operate according to a predefined force-displacement curve characteristic.