Keypad assembly
View Patent ↗A keypad assembly utilizes touch-detecting apparatus such as force sensors or touchpad assemblies for registering key presses. In exemplary embodiments, the keypad assembly is suitable for use in electronic devices such as a mobile telephones, calculators, hand-held computers, or the like, having single piece molded housings wherein the keypad assembly is at least partially encapsulated within the housing.
1. A keypad assembly, comprising:
a substrate;
a force sensor disposed on the substrate; and
an encapsulation layer molded onto the substrate over the force sensor, the substrate and force sensor being at least partially encapsulated by the encapsulation layer so that the force sensor is sandwiched between the substrate and encapsulation layer,
wherein the force sensor is suitable for sensing a force applied to the encapsulation layer over to the force sensor for registering a key press to the keypad assembly and wherein the force sensor includes means for canceling preload forces placed on the force sensor by molding of the encapsulation layer.
2. The keypad assembly as claimed in claim 1 , wherein the encapsulation layer is molded of a generally resilient material.
3. The keypad assembly as claimed in claim 1 , further comprising a key shape molded into the encapsulation layer over the force sensor for indicating a key of the keypad assembly.
4. The keypad assembly as claimed in claim 1 , further comprising indicia applied to the encapsulation layer over the force sensor for indicating a key of the keypad assembly.
5. A keypad assembly, comprising:
means for sensing a force;
means for supporting the force sensing means; and
means, molded onto the supporting means, for encapsulating the substrate and force sensing means, the force sensing means being sandwiched between the encapsulating means and the supporting means,
wherein the force sensing means is suitable for sensing a force applied to the encapsulating means over to the force sensing means for registering a key press to the keypad assembly and wherein the means for sensing a force includes means for canceling preload forces placed on the force sensor by molding of the encapsulation means.
6. The keypad assembly as claimed in claim 5 , wherein the encapsulating means is molded of a generally resilient material.
7. The keypad assembly as claimed in claim 5 , further comprising means for identifying the key of the keypad assembly.
8. An electronic device, comprising:
a keypad including a substrate and a force sensor disposed on the substrate; and
a housing molded onto the substrate so that the force sensor is at least partially encapsulated by the housing, the force sensor being sandwiched between the housing and the substrate for at least substantially eliminating spaces between the housing and the force sensor and the force sensor and the substrate,
wherein the force sensor is suitable for sensing a force applied to a portion of the housing over to the force sensor for registering a key press of the keypad and wherein the force sensor includes means for canceling preload forces placed on the force sensor by molding of the encapsulation housing.
9. The electronic device as claimed in claim 8 , wherein the housing is molded of a generally resilient material.
10. The electronic device as claimed in claim 8 , further comprising a key shape molded into the housing over the force sensor.
11. The electronic device as claimed in claim 8 , further comprising indicia applied to the housing over the force sensor.
12. A mobile telephone, comprising:
a keypad including a substrate and a force sensor disposed on the substrate; and
a housing molded onto the substrate so that the force sensor is at least partially encapsulated by the housing so that spaces between the housing and force sensor and the force sensor and the substrate are at least substantially eliminated,
wherein the force sensor is suitable for detecting a force applied to a portion of the housing over to the force sensor for registering a key press of the keypad and wherein the force sensor includes means for canceling preload forces placed on the force sensor by molding of the encapsulation housing.
13. The mobile telephone as claimed in claim 12 , wherein the housing is molded of a generally resilient material.
14. The mobile telephone as claimed in claim 12 , further comprising a key shape molded into the housing over the force sensor.
15. The mobile telephone as claimed in claim 12 , further comprising indicia applied to the housing over the force sensor.
16. A method for manufacturing a keypad assembly, comprising:
assembling a keypad, the keypad including a substrate having a force sensor disposed thereon for sensing a force applied thereto and registering a key press, and having a means for canceling preload forces placed on the force sensor;
overmolding an encapsulation layer onto the keypad so that the substrate and force sensor are at least partially encapsulated within the encapsulation layer, the force sensor being sandwiched between the housing and the substrate for at least substantially eliminating spaces between the housing and the force sensor and the force sensor and the substrate; and
canceling preload forces on the force sensor from the encapsulation layer.
17. The method as claimed in claim 16 , further comprising adjusting force registration by the force sensor for canceling preload forces placed on the force sensor by molding of the encapsulation layer.
18. The method as claimed in claim 16 , wherein the step of overmolding the encapsulation layer onto the keypad comprises molding a key shape into the encapsulation layer over the force sensor.
19. The method as claimed in claim 16 , further comprising applying indicia to the encapsulation layer over the force sensor.
20. The method as claimed in claim 16 , wherein the step of overmolding the encapsulation layer comprises molding a housing of an electronic device, the encapsulation layer forming a portion of the housing.
21. The keypad assembly as claimed in claim 1 , wherein the force sensor comprises a piezoelectric force cell.
22. The electronic device as claimed in claim 8 , wherein the force sensor comprises a piezoelectric force cell.
23. The mobile telephone as claimed in claim 12 , wherein the force sensor comprises a piezoelectric force cell.
24. A keypad assembly, comprising:
a substrate;
a force sensor disposed on the substrate; and
an encapsulation layer molded onto the substrate over the force sensor without formation of a compressible key dome, the substrate and force sensor being at least partially encapsulated by the encapsulation layer so that the encapsulation layer is in continuous contact with the force sensor,
wherein the force sensor is suitable for sensing a force applied to the encapsulation layer over to the force sensor for registering a key press to the keypad assembly and wherein the force sensor includes means for canceling preload forces placed on the force sensor by molding of the encapsulation layer.
25. The keypad assembly as claimed in claim 24 , wherein the encapsulation layer is molded of a generally resilient material.
26. The keypad assembly as claimed in claim 24 , further comprising a key shape molded into the encapsulation layer over the force sensor for indicating a key of the keypad assembly.
27. The keypad assembly as claimed in claim 24 , further comprising indicia applied to the encapsulation layer over the force sensor for indicating a key of the keypad assembly.
28. A keypad assembly, comprising:
a substrate;
a force sensor disposed on the substrate; and
an encapsulation layer molded onto the substrate over the force sensor, the substrate and force sensor being at least partially encapsulated by the encapsulation layer so that the force sensor is sandwiched between the housing and the substrate for eliminating spaces between the encapsulating layer and force sensor and the force sensor and the substrate,
wherein the force sensor is suitable for sensing a force applied to the encapsulation layer over the force sensor for registering a key press to the keypad assembly
and wherein the force sensor includes means for canceling preload forces placed on the force sensor by molding of the encapsulation layer.
29. The keypad assembly as claimed in claim 28 , wherein the encapsulation layer is molded of a generally resilient material.
30. The keypad assembly as claimed in claim 28 , further comprising a key shape molded into the encapsulation layer over the force sensor for indicating a key of the keypad assembly.
31. The keypad assembly as claimed in claim 28 , further comprising indicia applied to the encapsulation layer over the force sensor for indicating a key of the keypad assembly.