Touchpad pen-input and mouse controller

• US 5,995,084 A
• Filed: 01/17/1997
• Issued: 11/30/1999
• Est. Priority Date: 01/17/1997
• Status: Expired due to Fees

• Current Assignee: Cirrus Logic Incorporated
• Original Assignee: Tritech Microelectronics Ltd.
• Inventors: Lim, Swee Hock Alvin, Ong, Eng Yue, Ng, Maisy Mun Lan, Chan, Chow Fong, Geng, Xia
• Primary Examiner(s): Luu, Matthew
• Application Number:
  US08/785,739
• Time in Patent Office: 1,047 Days
• Field of Search: 345/156, 345/157, 345/173, 345/174, 345/175, 178/18, 178/19
• US Class Current: 345/173
• CPC Class Codes: G06F 3/03547 Touch pads, in which fingers can move on a surface
• CPC Class Codes: G06F 3/041 Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
• CPC Class Codes: G06F 3/045 using resistive elements, e.g. a single continuous surface or two parallel surfaces put in contact
• CPC Class Codes: G06F 3/0488 using a touch-screen or digitiser, e.g. input of commands through traced gestures
• CPC Class Codes: G06F 3/04883 for inputting data by handwriting, e.g. gesture or text

Abstract

Systems and methods for the detection of motions of a pointed object upon a writing surface such as a touchpad is disclosed. The motions will be detected and converted in a multiplexing analog-to-digital converter to digital codes representing the location of the pointed object and the pressure of the pointed object upon the touchpad. The location and the pressure will be translated into a pen detect signal indicating the presence of the pointed object upon the touchpad. The pen detect signal will be translated into a stroke signal to interpret a single tap, a double tap, and a tap and drag of the pointed object on the touchpad. The digital codes will be averaged to minimize noise and formed into an absolute coordinates digital code. The absolute coordinate digital code, the pressure digital code, and the pen detect signal will be converted to a touchpad-computer interface protocol. Further, multiple sets absolute coordinates will translated into a relative motion code. The absolute coordinates will be interpreted by an autocursor controller to determine if the pointed object has transited between a workzone and an edgezone of the touchpad to generate an autocursor code. The relative motion code, the stroke signal, and the autocursor code will converted to an industry standard computer input mouse protocol. An autopower control circuit and a battery gauge circuit will determine and control the battery condition.

Claims

1. A battery powered touchpad digitizing computer input device to detect a presence of a pointed object upon a surface, and to convert said presence to a set of digital codes that indicate absolute location and force of said pointed object upon said surface, if a pen input mode is selected, and to convert said presence to a speed and direction set of digital codes that conform to industry standard computer input mouse protocols, if a mouse mode is selected, comprising

a) a touchpad digitizer having a hard covering surface, a touch input transducer to convert said presence to electrical responses proportional to a distance of said pointed object from peripheral sides of said surface and proportional to the force of said pointed object upon said surface;

b) a touchpad driver circuit connected to said touchpad digitizer to provide an electrical stimulus to said touch input transducer;

c) a multiplexing analog-to-digital converter to accept a plurality of analog signals including the electrical responses and the pressure analog signal, and convert said plurality of analog signals to a plurality of digital codes that include a set of location digital codes representing the location of the pointed object upon the surface and a set of pressure digital codes representing the force of the pointed object upon the surface;

d) a pen detect circuit that receives the electrical responses to create a pen detect signal when said pointed object has been placed upon said touchpad digitizer;

e) a stroke interpreter to decode multiple occurrences the presence signal to create a stroke signal;

f) a touchpad computer interface connected to the multiplexed analog-to-digital converter, the pen detect circuit, and the stroke interpreter to receive and convert the location digital codes, the set of pressure digital codes, the pen detect signal, the stroke signal to a pen input protocol that contains an absolute location and pressure of said pointed object upon said touchpad digitizer and to transmit said protocol to a computer system for further processing if said pen-input mode is selected, and to convert the location digital codes, the pen detect signal, and the stroke signal to the computer input mouse protocols containing the relative motion and stroke information to control a cursor upon a display screen of said computer system, if the mouse mode is selected; and

g) a mode selector to select the pen-input mode if a mode select signal is at a first state and to select the mouse mode if the mode select signal is a second state.

2. The input device of claim 1 wherein the electrical responses varies in magnitude according to the location of said pointed object upon said touchpad.

3. The input device of claim 1 wherein the pointed object is selected from the set of pointed objects including a human finger, a stylus, and a pen.

4. The input device of claim 1 wherein the electrical response selected from the set of electrical responses that include a change in voltage, a change in current, and a change in frequency of an oscillating signal.

5. The input device of claim 1 further comprising a pressure sense circuit to convert the electrical responses to a pressure analog signal proportional to said force of the pointed object upon said surface.

6. The input device of claim 1 further comprising:

a) a battery to provide a voltage and a current to said touchpad digitizing computer input device and to said computer system, wherein said battery has a battery sense line is included as one of the plurality of analog signals connected to said multiplexing analog-to-digital converter, and converted to a set of battery power digital codes indicating the level of the voltage and the current

b) a battery gauge circuit to calculate from the battery power digital codes, a battery condition set of digital codes, which indicates a charging state of said battery, and to transmit said battery condition set of digital codes to the touchpad interface, wherein said touchpad-computer interface will transmit said battery condition set of digital codes to said computer system.

7. The input device of claim 1 wherein the touchpad computer interface comprises:

a) an absolute coordinate calculator to perform a method of coordinate averaging upon the location digital codes to create the absolute location digital codes that is a more consistent indication of the movement of the pointed object upon the touchpad digitizer;

b) a relative motion calculator to manipulate multiple sets of the location set of digital codes to create a relative motion set of digital codes that indicate the relative motion that is the speed and direction of the pointed object upon the touchpad;

c) an autocursor motion controller to interpret the absolute location set of codes to determine if said pointed object has transited between a workzone and an edgezone of said touchpad and to create an autocursor set of codes that contain the predefined relative motion set of digital codes to modify the autocursor set of codes if the location set of codes indicate that the pointed object is moving upon said touchpad in a new direction and at a new speed, to terminate the autocursor set of digital codes if the location set of codes indicates that the pointed object has transited from said edgezone to said workzone;

d) a mouse code conversion unit to convert the relative motion set of digital codes, the stroke signal, and the autocursor set of digital codes to the mouse movement set of digital codes;

e) a pen-input code conversion unit to convert the absolute location digital codes, the pressure digital codes, and the pen detect signal to the pen-input protocol; and

f) a data interface to convert the mouse movement set of digital codes if the mouse mode is selected, and the pen-input protocol if the pen-input mode is selected, to electrical signals and to transmit said electrical signals to said computer system for further processing.

8. The input device of claim 1 wherein the stroke signal will have:

a) a move action value is presence signal become active indicating the pointed object is present on the touchpad and is moving;

b) a single click value if the presence signal is active for a brief period of time followed by the presence signal being inactive to indicate a single tap of the touchpad;

c) a double click value if the presence signal is active for the brief period of time followed by the presence signal being inactive for the brief period of time followed by the presence signal being active for the brief period of time and followed by the presence signal becoming inactive to indicate a double tapping of the touchpad;

d) a press value if the presence signal is active for a brief period of time followed by the presence signal becoming active for a long period of time with no movement of the pointed and the object upon the touchpad; and

e) a press and drag value if the presence signal is active for the brief period of time followed by the presence signal being inactive for the brief period of time and followed by the presence signal becoming active for a long period of time to indicate a tap followed by the movement of the pointed object upon the touchpad.

9. The input device of claim 1 further comprising a power supply control and regulator circuit connected to said battery to control and regulate the voltage and the current.

10. The input device of claim 1 further comprising an autopower save circuit connected to the pen detect circuit to receive the pen detect signal, to interpret said pen detect signal to determine if said pointed object has not been in contact with the touchpad surface for a long period of time, and to create an autopower down signal that will be transferred to the power supply control and regulator circuit to command removal of the voltage and current from the touchpad input computer device and to restore said voltage and current if the pen detect signal indicates that the pointed object is in contact with the touchpad surface.

11. A touchpad digitizer computer input device control circuit to accept electrical response signals generated by a pointed object in contact with a touchpad digitizer, and to create a pen-input protocol if a pen-input mode is selected and to create a computer input mouse protocol if the mouse mode is selected, for transmission to a computer system for control of a cursor upon a display screen, to signal an end of stroke in handwriting recognition programs, and to provide stroke, location, and pressure information to signature entry and verification programs, comprising:

a) a touchpad driver circuit connected to said touchpad digitizer to provide an electrical stimulus to said touchpad digitizer;

b) a multiplexing analog-to-digital converter to accept a plurality of analog signals including the electrical responses and the pressure analog signal, and convert said plurality of analog signals to a plurality of digital codes that include a set of location digital codes representing the location of the pointed object upon the surface and a set of pressure digital codes representing the force of the pointed object upon the surface;

c) a pen detect circuit that receives the electrical responses to create a pen detect signal when said pointed object has been placed upon said touchpad digitizer;

d) a data interface to convert to electrical signals the mouse movement set of digital codes if the mouse mode is selected, and the pen-input protocol if the pen-input mode is selected, and to transmit said electrical signals to said computer system for further processing;

e) a stroke interpreter to decode multiple occurrences the presence signal to create a stroke signal; and

f) a mode selector to select the pen-input mode if a mode select signal is at a first state, and to select the mouse mode if the mode select signal is at a second state.

12. The control circuit of claim 11 wherein the electrical responses varies in magnitude according to the location of said pointed object upon said touchpad.

13. The control circuit of claim 11 wherein the pointed object is selected from the set of pointed objects including a human finger, a stylus, and a pen.

14. The control circuit of claim 11 wherein the electrical response selected from the set of electrical responses that include a change in voltage, a change in current, and a change in frequency of an oscillating signal.

15. The control circuit of claim 11 further comprising a pressure sense circuit to convert the electrical responses to a pressure analog signal proportional to said force of the pointed object upon said surface.

16. The control circuit of claim 11 wherein the touchpad computer interface comprises:

a) an absolute coordinate calculator to perform a method of coordinate averaging upon the location digital codes to create the absolute location digital codes that is a more consistent indication of the movement of the pointed object upon the touchpad digitizer;

b) a relative motion calculator to manipulate multiple sets of the location set of digital codes to create a relative motion set of digital codes that indicate the relative motion that is the speed and direction of the pointed object upon the touchpad;

c) an autocursor motion controller to interpret the absolute location set of codes to determine if said pointed object has transited between a workzone and an edgezone of said touchpad and to create an autocursor set of codes that contain a predefined relative motion set of digital codes to modify the autocursor set of codes if the location set of codes indicate that the pointed object is moving upon said touchpad in a new direction and at a new speed, to terminate the autocursor set of digital codes if the location set of codes indicates that the pointed object has transited from said edgezone to said workzone;

d) a mouse code conversion unit to convert the relative motion set of digital codes, the stroke signal, and the autocursor set of digital codes to the mouse movement set of digital codes;

e) a pen-input code conversion unit to convert the absolute location digital codes, the pressure digital codes, and the pen detect signal to the pen-input protocol; and

f) a data interface to convert the mouse movement set of digital codes if the mouse mode is selected, and the pen-input protocol if the pen-input mode is selected, to electrical signals and to transmit said electrical signals to said computer system for further processing.

17. The control circuit of claim 11 wherein the stroke signal will have:

a) a move action value is presence signal become active indicating the pointed object is present on the touchpad and is moving;

b) a single click value if the presence signal is active for a brief period of time followed by the presence signal being inactive to indicate a single tap of the touchpad;

c) a double click value if the presence signal is active for the brief period of time followed by the presence signal being inactive for the brief period of time followed by the presence signal being active for the brief period of time and followed by the presence signal becoming inactive to indicate a double tapping of the touchpad;

d) a press value if the presence signal is active for a brief period of time followed by the presence signal becoming active for a long period of time with no movement of the pointed and the object upon the touchpad; and

e) a press and drag value if the presence signal is active for the brief period of time followed by the presence signal being inactive for the brief period of time and followed by the presence signal becoming active for a long period of time to indicate a tap followed by the movement of the pointed object upon the touchpad.

18. The control circuit of claim 11 further comprising:

a) a battery to provide a voltage and a current to said touchpad digitizing computer input device and to said computer system, wherein said battery has a battery sense line is included as one of the plurality of analog signals connected to said multiplexing analog-to-digital converter, and converted to a set of battery power digital codes indicating the level of the voltage and the current

b) a battery gauge circuit to calculate from the battery power digital codes, a battery condition set of digital codes, which indicates a charging state of said battery, and to transmit said battery condition set of digital codes to the touchpad interface, wherein said touchpad-computer interface will transmit said battery condition set digital codes to said computer system.

19. The control circuit of claim 11 further comprising a power supply control and regulator circuit connected to said battery to control and regulate the voltage and the current.

20. The control circuit of claim 11 further comprising an autopower save circuit connected to the pen detect circuit to receive the pen detect signal, to interpret said pen detect signal to determine if said pointed object has not been in contact with the touchpad surface for a long period of time, and to create an autopower down signal that will be transferred to the power supply control and regulator circuit to command selective removal of the voltage and current from the touchpad input computer device and to restore said voltage and current if the pen detect signal indicates that the pointed object is in contact with the touchpad surface.