Raw data track pad device and system

• US 7,719,522 B2
• Filed: 09/24/2004
• Issued: 05/18/2010
• Est. Priority Date: 09/24/2004
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Cinereski, Stephanie, Bronstein, Chad, Hotelling, Steven P., Lyon, Benjamin
• Primary Examiner(s): Hjerpe; Richard
• Assistant Examiner(s): Nguyen; Jennifer T
• Application Number:
  US10/949,060
• Publication Number:
  US 20060066582A1
• Time in Patent Office: 2,062 Days
• Field of Search: 345/156, 345/157, 345173-178, 178 1801- 1809
• US Class Current: 345/173
• CPC Class Codes: G06F 3/04166 Details of scanning methods, e.g. sampling time, grouping of sub areas or time sharing with display driving Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally G06F3/04184
• CPC Class Codes: G06F 3/044 by capacitive means
• CPC Class Codes: G06F 3/0488 using a touch-screen or digitiser, e.g. input of commands through traced gestures

Abstract

An input device and system are described that acquires (measures) raw track pad sensor data and transmits this data to a host computer where it is analyzed by an application executing on one or more host computer central processing units. The resulting input processing architecture provides a track pad input device that is both lower in cost to manufacture and more flexible than prior art track pad input devices. Lower costs may be realized by eliminating the prior art'"'"'s dedicated track pad hardware for processing sensor data (e.g., a processor and associated firmware memory). Increased flexibility may be realized by providing feature set functionality via software that executes on the host computer. In this architecture, track pad functionality may be modified, updated and enhanced through software upgrade procedures.

Claims

1. A track pad input device comprising:

a capacitive track pad sensor having a plurality of sensing elements, each sensing element associated with a region of the capacitive track pad sensor;

means for measuring and selectively encoding a digital capacitance value for each of the plurality of sensing elements, the digital capacitance value representing a raw capacitance measurement of the sensing element; and

means for transmitting the plurality of digital capacitance values to a host processor for processing, wherein the digital capacitance values are aggregated into packets and transmitted according to a universal serial bus protocol, and the host processor is also at least partially responsible for executing user-level tasks,

wherein the track pad sensor comprises a capacitive sensor array, and the means for measuring comprises means for selectively stimulating each of the plurality of sensing elements, means for determining a time required to stimulate each selected sensing element to a specified event, and means for encoding the determined time into a digital value.

2. The track pad input device of claim 1, wherein the track pad input device does not include a means for determining a user action corresponding to manipulation of the track pad sensor.

3. The track pad input device of claim 1, wherein the specified event comprises charging a known capacitance to a specified voltage.

4. The track pad input device of claim 1, wherein a plurality of packets of digital capacitance values is transmitted in a single frame to the host processor under the universal serial bus protocol.

5. The track pad input device of claim 1, wherein the sensing elements comprise at least one of (i) rows of the capacitive sensor array and (ii) columns of the capacitive sensor array.

6. The track pad input device of claim 1, wherein the sensing elements comprise pixels of the capacitive sensor array.

7. A computer system, comprising:

one or more host processors for executing, at least in part, user-level tasks;

a display unit operatively coupled to the host processor;

a first communication circuit operatively coupled to at least one of the one or more host processors; and

a track pad input device comprising

a capacitive track pad sensor having a plurality of sensing elements, each sensing element associated with a region of the capacitive track pad sensor;

a data acquisition circuit electrically coupled to the track pad sensor, the data acquisition circuit selectively encoding a digital capacitance value representing a raw capacitance measurement for each of the plurality of sensing elements; and

a second communication circuit for transmitting the digital capacitance values to the first communication circuit, wherein the digital capacitance values are aggregated into packets and transmitted according to a universal serial bus protocol, and at least one of the one or more host processors determines, after receiving the packets, an action corresponding to manipulation of the track pad sensor,

wherein the track pad sensor comprises a capacitive sensor array, and the data acquisition circuit comprises means for selectively stimulating each of the plurality of sensing elements, means for determining a time required to stimulate each selected sensing element to a specified event, and means for encoding the determined time into a digital capacitance value.

8. The computer system of claim 7, wherein a plurality of packets of digital capacitance values is transmitted in a single frame under the universal serial bus protocol.

9. The computer system of claim 7, wherein the specified event comprises charging a known capacitance to a specified voltage.

10. The computer system of claim 7, wherein the data acquisition circuit is adapted to repeatedly encode digital capacitance values for each of the plurality of sensing elements.

11. The track pad input device of claim 7, wherein the sensing elements comprise at least one of (i) rows of the capacitive sensor array and (ii) columns of the capacitive sensor array.

12. The track pad input device of claim 7, wherein the sensing elements comprise pixels of the capacitive sensor array.