INTEGRATED IN-PLANE SWITCHING

• US 20120313894A1
• Filed: 08/23/2012
• Published: 12/13/2012
• Est. Priority Date: 06/13/2007
• Status: Active Grant

• Current Assignee: John Z. Zhong, Steve Porter Hotelling
• Original Assignee: John Z. Zhong, Steve Porter Hotelling
• Inventors: HOTELLING, Steve Porter, ZHONG, John Z.
• Granted Patent: US 9,104,258 B2
• Time in Patent Office: Days
• US Class Current: 345/174
• CPC Class Codes: G02F 1/134363 for applying an electric field parallel to the substrate, i.e. in-plane switching [IPS]
• CPC Class Codes: G06F 2203/04104 Multi-touch detection in digitiser, i.e. details about the simultaneous detection of a plurality of touching locations, e.g. multiple fingers or pen and finger
• CPC Class Codes: G06F 2203/04112 Electrode mesh in capacitive digitiser: electrode for touch sensing is formed of a mesh of very fine, normally metallic, interconnected lines that are almost invisible to see. This provides a quite large but transparent electrode surface, without need for ITO or similar transparent conductive material
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/04184 Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally
• CPC Class Codes: G06F 3/044 by capacitive means
• CPC Class Codes: G06F 3/0443 using a single layer of sensing electrodes

Abstract

This relates to adding multi-touch functionality to a display without the need of a separate multi-touch panel or layer overlaying the display. Instead, embodiments of the invention can advantageously utilize existing display circuitry to provide multi-touch functionality while adding relatively little circuitry that is specific to the multi-touch functionality. Thus, by sharing circuitry for the display and the multi-touch functionalities, embodiments of the invention can be implemented at a lower cost than the alternative of superimposing additional multi-touch related layers onto an existing display panel. Furthermore, since the display and multi-touch functionality can be implemented on the same circuit, they can be synchronized so that noise resulting from the display functionality does not detrimentally affect the multi-touch functionality and vice versa.

Claims

1. A touch enabled display comprising:

a display having a plurality of cells, each cell comprising at least two electrodes,

one or more stimulus regions, each stimulus region including one or more adjacent cells of the plurality of cells;

one or more sensor regions, each sensor region including one or more adjacent cells of the plurality of cells, the one or more sensor regions disposed adjacent the one or more stimulus regions;

one or more guard regions, at least one guard region being disposed between the adjacent one or more stimulus region and the one or more sensor regions; and

a control device for;

creating a plurality of different voltage differentials between the at least two electrodes of one or more of the plurality of cells in order to cause an image to appear at the display;

discharging the voltage differentials between the at least two electrodes of one or more of the plurality of cells; and

after discharging, stimulating one or more of the stimulus regions, and

sensing a plurality of mutual capacitances between the one or more stimulated stimulus regions and one or more sensor regions adjacent the one or more stimulated stimulus regions.

2. The display of claim 1, wherein the one or more stimulus regions include a first and a second stimulus region, and the one or more sensor regions includes a first sensor region disposed between the first and second stimulus regions, and wherein the one or more guard regions includes a first guard region disposed between the first stimulus region and the first sensor region and a second guard region disposed between the first sensor region and the second stimulus region.

3. The display of claim 1, wherein each guard region comprises:

a data line;

a driven electrode formed by one of the at least two electrodes;

a select line;

a switch responsive to a signal on the select line for connecting the data line to the driven electrode; and

wherein the guard regions are configurable during a touch scanning mode of operation by connecting the data lines to a fixed voltage and driving select line associated with the connected data line such that the driven electrode and the data lines are electrically connected to one another.

4. The display of claim 3, wherein the fixed voltage is ground.

5. The display of claim 1, wherein each guard region comprises at least one cell, each of the at least one cell comprising:

a data line;

a driven electrode;

formed by one of the at least two electrodes

a first switch for connecting the data line to the driven electrode; and

a counter electrode formed by another of the at least two electrodes;

the display further comprising;

a select line;

a counter data line; and

the first switch responsive to driving of select line for connecting the data line to the driven electrode;

a second switch responsive to driving of the select line for connecting the counter data line to the counter electrode;

wherein the guard regions are configurable during a touch scanning mode of operation such that the first switch is operable for connecting the data line to the driven electrode, and the second switch is operable for connecting the counter data line to the counter electrode, and the counter data line and the data line being connected to a common fixed voltage.

6. The touch enabled display of claim 1, wherein discharging the voltage differentials comprise coupling the two electrodes to a common voltage.

7. The touch enabled display of claim 1, wherein creating the plurality of voltage differentials is performed between the at least two electrodes for each cell in the one or more sensor regions and for each cell in the one or more of one or more stimulus regions.

8. The touch enabled display of claim 7, wherein discharging the voltage differentials is performed between the at least two electrodes for each cell in the one or more sensor regions and for each cell in the one or more of one or more stimulus regions.

9. A touch enabled display comprising:

a display having a plurality of cells, each cell comprising at least two electrodes,

one or more stimulus regions, each stimulus region including one or more adjacent cells of the plurality of cells;

one or more sensor regions, each sensor region including one or more adjacent cells of the plurality of cells;

one or more guard regions, at least one guard region being disposed between one or more stimulus regions adjacent the one or more sensor regions; and

a control device for;

charging and subsequently discharging the at least two electrodes of the one or more stimulus region and the one or more sensor regions; and

after discharging, stimulating one or more of the stimulus regions, and

sensing a plurality of mutual capacitances between the one or more stimulated stimulus regions and one or more sensor regions adjacent the one or more stimulated stimulus regions.

10. A touch display system, comprising:

a display containing a plurality of cells, each cell having a driven electrode and a counter electrode;

a plurality of color data lines;

a plurality of counter data lines; and

a plurality switching elements associated with the plurality of counter data lines and the plurality of color data lines and controlled by a control circuit to selectively connect one or more of the plurality of counter and color data lines for operating in a display mode of operation or in touch sense mode of operation;

wherein;

in the display mode of operation, the driven electrodes of the plurality of cells is coupled to at least one of the plurality of color data lines to receive a drive voltage, and the counter electrodes of the plurality of cells is coupled to ground or to a voltage different from a drive voltage; and

in at least a part of the touch sense mode of operation, the driven and counter electrodes of the plurality of cells are connected such as to discharge any voltage differential therebetween; and

wherein the control circuit is further configured to, for a guard group of cells, cause switching elements associated with cells of the guard group of cells to connect color data lines associated with cells of the guard group of cells to a predefined voltage.

11. The touch display system of claim 10, wherein the guard group of cells comprises a plurality of guard regions, each guard region being positioned between an adjacent touch stimulus region and an adjacent charge sensor region.

12. The touch display system of claim 10, wherein the predefined voltage is ground.

13. A method for providing touch functionality for a display having a plurality of cells, each cell comprising at least two electrodes, the display having one or more stimulus regions, each stimulus region including one or more adjacent cells, and the display having one or more sensor regions, each sensor region including one or more adjacent cells, the stimulus regions adjacent the sensor regions;

the display having one or more guard regions, at least one guard region being placed between adjacent stimulus and sensor regions,

the method comprising;

creating a plurality of different voltage differentials between the at least two electrodes of one or more excited cells of the plurality of cells in order to cause an image to appear at the display;

discharging the voltage differentials between the at least two electrodes of one or more touch enabled cells of the one or more excited cells; and

after discharging, sensing a plurality of mutual capacitances between adjacent cells of the one or more touch enabled cells in order to sense touch events at the display; and

connecting at least one of the at least two electrodes of each cell belonging to a guard region to a fixed voltage during a touch sensing period.

14. The method of claim 13, wherein the sensing the plurality of mutual capacitances further includes:

sensing the amount of charge collected at one or more of the respective sensor regions as a result of the capacitive coupling of the sensor regions with adjacent stimulus regions and the stimulation of the adjacent stimulus regions by the stimulation signal.

15. The method of claim 14, wherein:

the sensing the amount of charge collected at one or more of the sensor regions further includes coupling at least one of the two electrodes of cells of the one or more sensor regions to one or more charge amplifiers; and

stimulating each stimulus region with the stimulation signal further includes stimulating at least one of the two electrodes of each cell within each stimulus region with the stimulation signal.

16. The method of claim 15, wherein each cell is connected to a color data line and a counter data line, the color data line being connected to a first electrode and the counter data line being connected to a second electrode of the cell'"'"'s two electrodes and wherein:

creating the voltage differentials between pairs of electrodes further includes connecting the counter data line connected to a cell to a predefined voltage and applying a voltage, different from the predefined voltage, to the color data line connected to the cell.

17. The method of claim 16, wherein stimulating each stimulus region with a stimulation signal further includes sending the stimulation signal to the counter and color data lines of one or more cells within the stimulus regions.

18. The method of claim 16, wherein sensing the amount of charge collected at one or more of the respective sensor regions further includes coupling at least one of the counter and color data lines of one or more cells within the one or more of the sensor regions to a charge amplifier.

19. The method of claim 13, further including dynamically changing one or more of the stimulus, sensor and guard regions by dynamically changing the state of one or more cells vis-à

-vis the regions the cells belong to.