Analog data-input device provided with a pressure sensor of a microelectromechanical type

• US 8,044,929 B2
• Filed: 03/30/2006
• Issued: 10/25/2011
• Est. Priority Date: 03/31/2005
• Status: Active Grant

• Current Assignee: STMicroelectronics SRL (STMicroelectronics NV)
• Original Assignee: STMicroelectronics SRL (STMicroelectronics NV)
• Inventors: Sassolini, Simone, Combi, Chantal, Baldo, Lorenzo, Del Sarto, Marco
• Primary Examiner(s): Eisen; Alexander
• Assistant Examiner(s): PHAM, VIET DAVID
• Application Number:
  US11/393,377
• Publication Number:
  US 20060262088A1
• Time in Patent Office: 2,035 Days
• Field of Search: 345/156, 345/161, 737/18, 737/15, 737/21
• US Class Current: 345/156
• CPC Class Codes: G01L 19/141 Monolithic housings, e.g. molded or one-piece housings
• CPC Class Codes: G01L 19/147 Details about the mounting of the sensor to support or covering means
• CPC Class Codes: G01L 9/0045 Diaphragm associated with a buried cavity
• CPC Class Codes: G01L 9/0054 integral with a semiconducting diaphragm
• CPC Class Codes: G06F 3/0338 with detection of limited linear or angular displacement of an operating part of the device from a neutral position, e.g. isotonic or isometric joysticks
• CPC Class Codes: G06F 3/041 Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
• CPC Class Codes: H01H 13/785 characterised by the material of the contacts, e.g. conductive polymers
• CPC Class Codes: H01H 2201/02 Piezo element
• CPC Class Codes: H01H 2201/036 Variable resistance
• CPC Class Codes: H01H 2221/012 Joy stick type
• CPC Class Codes: H01H 2239/01 combined with other elements on the same substrate
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/16195 Flat cap [not enclosing an internal cavity]
• CPC Class Codes: H01L 2924/181 Encapsulation

Abstract

In a data-input device an actuator element that can be manually actuated, and a sensor mechanically coupled to the actuator element. The sensor is formed in a body of semiconductor material housing a first sensitive element, which detects the actuation of the actuator element and generates electrical control signals. The first sensitive element is a microelectromechanical pressure sensor, formed by: a cavity made within the body; a diaphragm made in a surface portion of the body and suspended above the cavity; and piezoresistive transducer elements integrated in peripheral surface portions of the diaphragm in order to detect its deformations upon actuation of the actuator element.

Claims

1. A data-input device, comprising:

a package having a chamber formed therein;

a sensor including a semiconductor material body positioned inside the chamber, said body housing first and second sensitive elements, each having a microelectromechanical pressure sensor configured to detect pressure and to generate a respective electrical control signal corresponding to the detected pressure;

a flexible membrane closing the chamber and delimiting a main surface of the package, the membrane being spaced apart from the sensor; and

an elastomeric material positioned in the chamber between the membrane and the sensor, and configured to transmit actuating pressure, applied to an outer surface of the membrane, from the membrane to the sensor.

2. The device according to claim 1 wherein each of said first and second sensitive elements comprises a cavity formed in said body, a diaphragm formed in a surface portion of said body and suspended above said cavity, and piezoresistive transducer elements integrated in peripheral surface portions of said diaphragm and configured to detect deformations of said diaphragm upon actuation of said actuator element.

3. The device according to claim 1 wherein said flexible membrane forms an actuator element.

4. The device according to claim 1 wherein an actuator element comprising a flexible structure shaped to form keys is arranged on top of said flexible membrane.

5. The device according to claim 1 wherein said body houses further sensitive elements, each of said further sensitive elements configured to detect pressure and to generate a respective electrical control signal corresponding to the detected pressure.

6. The device according to claim 5, wherein said body further houses an interface electronic circuit, electrically connected to each of said sensitive elements and configured to determine a position of the actuating pressure on the membrane on the basis of relative values of the respective electrical control signals.

7. The device according to claim 5 wherein said first and second sensitive elements and further sensitive elements are arranged with respect to one another in a geometrical configuration chosen from among a triangle, a cross, and an array.

21. The device of claim 1, further comprising a circuit coupled to the sensor and configured to determine a location of the actuating pressure on the membrane by determining, from the respective electrical control signals, which of the first and second sensitive elements has undergone a greater deformation.

24. The device of claim 1 wherein the semiconductor material body is affixed to an inner wall of the chamber, opposite the membrane.

8. A data-input device, comprising:

an actuator element; and

a sensor mechanically coupled to said actuator element and including first and second sensitive elements integrated in respective bodies of semiconductor material, each of said first and second sensitive elements including a microelectromechanical pressure sensor configured to detect a respective direction of actuation of said actuator element and to generate electrical control signals;

a package having an open chamber formed therein, the first and second sensitive elements being positioned inside the chamber;

a membrane positioned over an opening of the chamber, the actuator element being coupled to the membrane; and

an elastomeric material positioned inside of the chamber, covering the sensor and acting to transmit pressure exerted on the membrane to the sensor, thereby mechanically coupling the actuator element to the sensor.

9. The device according to claim 8 wherein said sensor also includes further sensitive elements integrated in respective bodies of semiconductor material, each of said further sensitive elements including a microelectromechanical pressure sensor configured to detect a respective direction of actuation of said actuator element, and wherein said first and second sensitive elements and further sensitive elements are arranged with respect to one another in a geometrical configuration chosen from among a triangle, a cross, and an array.

10. An electronic apparatus comprising:

a data-input device having;

a chamber;

an elastomeric material substantially filling the chamber;

an actuator element including a membrane closing the chamber;

a sensor including a body made of semiconductor material positioned in the chamber, the elastomeric material being configured to transfer pressure from the membrane to the body of semiconductor material, said body housing first and second sensitive elements configured to detect respective directions of actuation of the actuator element and to generate respective electrical control signals, each of said first and second sensitive elements including a microelectromechanical pressure sensor.

11. The apparatus according to claim 10, comprising a display controllable by means of said data-input device.

12. The apparatus according to claim 10 wherein the apparatus is one of:

a mobile phone, a PDA, a personal computer, a game-computer console, or a remote control.

20. The apparatus according to claim 10 wherein each of the sensitive elements includes a cavity formed in the body of semiconductor material and covered by a diaphragm.

25. The apparatus of claim 10 wherein the body of semiconductor material is affixed to an inner wall of the chamber, opposite the membrane.

13. A pressure sensor comprising:

a body of semiconductor material;

a plurality of diaphragms formed over respective cavities in the body;

a circuit formed in the body and configured to detect deflection of each of the plurality of diaphragms and produce a signal corresponding to a degree of deflection of each; and

a package having a chamber within which the body is mounted;

a membrane closing the chamber and forming an upper surface of the package;

an elastomeric material covering the body and substantially filling a space between the membrane and the body such that pressure on a region of the upper surface of the package is transmitted by the elastomeric material to the body and results in selective deflection of one or more of the plurality of diaphragms that lie closest to that region of the upper surface.

14. The pressure sensor of claim 13, comprising a plurality of piezoresistive elements formed in the body adjacent to each of the plurality of diaphragms and configured to be responsive to deflection of the respective diaphragm, the circuit being coupled to the piezoresistive elements such that responses of the piezoresistive elements to deflection of the respective diaphragm are detected by the circuit.

15. The pressure sensor of claim 13 wherein the plurality of diaphragms are arranged with respect to one another in a geometrical configuration chosen from among a triangle, a cross, and an array.

23. The pressure sensor of claim 13 wherein the circuit is configured to determine on which of a plurality of regions on the upper surface of the package the pressure is applied, based on a relative degree of deflection of each the plurality of diaphragms.

26. The pressure sensor of claim 13 wherein the body of semiconductor material is bonded to a bottom internal surface of the chamber.

16. A device comprising:

a pressure sensor including a body of semiconductor material and a plurality of diaphragms formed over respective cavities in the body;

deflection means for selectively deflecting individual ones of the plurality of diaphragms; and

a circuit configured to detect deflection of each of the plurality of diaphragms and command operation of one of a plurality of functions of the device in response to a combination of deflections detected.

17. The device of claim 16 wherein the circuit is further configured to detect a degree of deflection of each of the plurality of diaphragms.

18. The device of claim 16 wherein the deflection means comprises a keypad.

19. The device of claim 16 wherein the deflection means comprises a membrane positioned above the body of semiconductor material, and a space between the membrane and the body filled with an elastomeric material.

22. A data input device, comprising:

a package having a chamber;

a sensor positioned in the chamber and including a semiconductor material body having a plurality of sensitive elements each configured to generate a control signal corresponding to pressure applied to the respective sensitive element, the chamber being substantially filled with an elastomeric material for transmission of pressure from an actuator element to the plurality of sensitive elements;

a circuit coupled to the sensor and configured to determine, from the respective control signals, a direction of movement of the actuator element, on the basis of a relative pressure applied to the respective sensitive elements by the movement of the actuator element, wherein the actuator element includes a membrane positioned over the chamber, and the semiconductor material body is affixed to an inner wall of the chamber, opposite the membrane.