Stylus based input devices utilizing a magnetic random access momory array

• US 6,781,578 B2
• Filed: 01/02/2002
• Issued: 08/24/2004
• Est. Priority Date: 01/02/2002
• Status: Expired due to Term

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Sharma, Manish
• Primary Examiner(s): Shalwala, Bipin
• Assistant Examiner(s): Said, Mansour M.
• Application Number:
  US10/038,485
• Publication Number:
  US 20030122790A1
• Time in Patent Office: 965 Days
• Field of Search: 345/156, 345/157, 345/158, 345/159, 345/160, 345/162, 345/82, 345/86, 345/87, 345/98, 345/173, 345/174, 345/175, 345/176, 345/177, 345/178, 345/419, 345/581, 345/582, 345/587, 345/589, 345/592, 345/606, 178/18.01, 178/18.02, 178/18-3-, 178/19.01, 178/19-2-, 178/20-1-, 361/760, 361/785, 361/737, 361/797, 361/684, 361/685, 128/660.03, 128/696, 128/697, 128/702, 128/704, 128/708, 128/925
• US Class Current: 345/173
• CPC Class Codes: G06F 3/046 by electromagnetic means
• CPC Class Codes: G09G 2300/08 Active matrix structure, i.e. with use of active elements, inclusive of non-linear two terminal elements, in the pixels together with light emitting or modulating elements
• CPC Class Codes: G09G 2300/0809 Several active elements per pixel in active matrix panels
• CPC Class Codes: G09G 2300/0852 being a dynamic memory with more than one capacitor
• CPC Class Codes: G09G 3/20 for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters

Abstract

A digitizing tablet is disclosed that includes an array of magnetic random access memory cells and a signal processor, coupled to the array. The array of magnetic random access memory cells may be modified by at least one externally-applied magnetic field, each memory cell having a magnetic bit that changes orientation upon application of an electric field or the externally-applied magnetic field to produce a modified electrical signal based on the orientation of the bit when a read signal is applied across the array. The signal processor, which couples to the array of magnetic random access memory cells, is utilized to convey the signal from each memory cell to a display device.

Claims

1. A digitizing tablet comprising:

an array of magnetic memory cells, each memory cell having a magnetic bit that changes orientation upon active application of at least one externally-applied magnetic field, the magnetic field being applied with at least one pointing device having a magnetic tip, and the orientation of the bit producing an electrical signal during a read operation of the array; and

a signal processor that couples to the array of magnetic memory cells and receives the electrical signal from the array, processes the electrical signal, and generates an imaging signal for output to an imaging device.

2. The digitizing tablet as claimed in claim 1 wherein each MRAM cell has a form factor of less than one micron.

3. The digitizing tablet as claimed in claim 1 wherein the magnetic field is a fixed field.

4. The digitizing tablet as claimed in claim 1 wherein the magnetic field can vary during interaction with a MRAM cell.

5. The digitizing tablet as claimed in claim 1 further comprising a stylus that has a first tip for actively applying the at least one magnetic field to the MRAM array.

6. The digitizing tablet as claimed in claim 5 wherein the stylus can interact with the MRAM array to indicate an action to be performed.

7. The digitizing tablet as claimed in claim 5 wherein the stylus included a current-carrying coil to interact with the MRAM array.

8. The digitizing tablet as claimed in claim 1 wherein a second externally-applied magnetic field can interact with the MRAM array simultaneously with the at least one externally-applied magnetic field.

9. The digitizing tablet as claimed in claim 1 further comprising a display device, mated to the MRAM array and coupled to the signal processing unit, such that image data from the MRAM array and signal processing device is used to display information on the display device proximate where the magnetic field modified the magnetic bits of cells within the MRAM array.

10. A method of converting user input into image data, comprising:

providing an array of magnetic random access memory cells, each MRAM cell having a magnetic bit that changes orientation upon active application of at least one externally applied magnetic field;

applying at least one external magnetic field to the array to change the magnetic bit orientation of at least a portion of the MRAM cells, wherein the magnetic field is applied with at least one pointing device having magnetic tip;

applying an input electric signal to the array; and

reading an output electric signal from each cell for display.

11. A method of converting user input into image data according to claim 10 further comprising displaying an image corresponding to the applied magnetic field based on the output electric signals of the array of MRAM cells.

12. A method of converting user input into image data according to claim 11 further comprising mating a display device to the MRAM array wherein the displayed image corresponds to the location proximate where the magnetic field is applied to the MRAM array.

13. A method of converting user input into image data according to claim 11 further comprising, in the vent of an electrical power stoppage to a display device and the MRAM array, redisplaying the image based on the magnetic bit orientation of the MRAM cells within the MRAM array upon return of electrical power.

14. A method of converting user input into image data according to claim 10 also comprising applying a second magnetic field, independent of the first magnetic field, to change the magnetic bit orientation of at least a second portion of the MRAM cells.

15. A method of converting user input into image data according to claim 10 wherein the magnetic field applying step further comprises selectively varying the magnetic field during application to affect the magnetic bit orientation of the at least a portion of MRAM cells.

16. A method of converting user input into image data according to claim 10 also comprising:

sensing an action performed by a user; and

performing a function associated with the sensed action.

17. A method of converting user input into image data according to claim 10 wherein the magnetic bit orientation for each cell is maintained without refresh.

18. A digitizing tablet comprising:

an array of magnetic random access memory cells that may be modified by at least one externally applied magnetic field, the magnetic field being applied with at least one pointing device having a magnetic tip, each memory cell having a magnetic bit that changes orientation upon application of an electric field or the externally-applied magnetic field to produce a modified electrical signal based on the orientation of the bit when an electric field is applied across the array; and

a signal processing device, coupled to the array of magnetic random access memory cells, that is utilized to process the modified electrical signals for output to a display device.

19. A digitizing tablet comprising:

a plurality of magnetic memory circuits capable of indefinitely retaining a magnetic field impressed upon at least one of the plurality of magnetic memory circuits via active application of at least one externally-applied magnetic field to at least one of the plurality magnetic memory circuits, the magnetic field being applied with at least one pointing device having a magnetic tip;

a control circuit that couples to the plurality of magnetic memory circuits and that performs a read function of the plurality of magnetic memory circuits to produce electrical signals based on the magnetic fields; and

a signal processor that couples to the control circuit and receives the electrical signals from each memory cell, processes the electrical signals, and generates an imaging signal for output to an imaging device.