Touch screen calibration and update methods

• US 9,052,771 B2
• Filed: 03/22/2011
• Issued: 06/09/2015
• Est. Priority Date: 11/04/2002
• Status: Active Grant

• Current Assignee: Neonode, Inc.
• Original Assignee: Neonode, Inc.
• Inventors: Goertz, Magnus, Eriksson, Thomas, Shain, Joseph, Jansson, Anders, Kvist, Niklas, Pettersson, Robert, Sparf, Lars, Karlsson, John
• Primary Examiner(s): Johnson, Allison
• Assistant Examiner(s): CHOWDHURY, AFROZA Y
• Application Number:
  US13/053,229
• Publication Number:
  US 20110169781A1
• Time in Patent Office: 1,540 Days
• Field of Search: 345/169, 345/173, 345/175, 345/179
• US Class Current: 1/1
• CPC Class Codes: G06F 2203/04101 2.5D-digitiser, i.e. digitiser detecting the X/Y position of the input means, finger or stylus, also when it does not touch, but is proximate to the digitiser's interaction surface and also measures the distance of the input means within a short range in the Z direction, possibly with a separate measurement setup
• 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 2203/04808 Several contacts: gestures triggering a specific function, e.g. scrolling, zooming, right-click, when the user establishes several contacts with the surface simultaneously; e.g. using several fingers or a combination of fingers and pen
• 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 3/0418 for error correction or compensation, e.g. based on parallax, calibration or alignment
• CPC Class Codes: G06F 3/042 by opto-electronic means
• CPC Class Codes: G06F 3/0421 by interrupting or reflecting a light beam, e.g. optical touch-screen
• CPC Class Codes: G06F 3/0425 using a single imaging device like a video camera for tracking the absolute position of a single or a plurality of objects with respect to an imaged reference surface, e.g. video camera imaging a display or a projection screen, a table or a wall surface, on which a computer generated image is displayed or projected tracking a projected light spot to determine a position on a display surface G06F3/0386
• CPC Class Codes: G06F 3/0428 by sensing at the edges of the touch surface the interruption of optical paths, e.g. an illumination plane, parallel to the touch surface which may be virtual sensing beam interruptions in a planar beam grid of an optical touch-screen G06F3/0421
• CPC Class Codes: G06F 3/04845 for image manipulation, e.g. dragging, rotation, expansion or change of colour
• CPC Class Codes: G06F 3/04883 for inputting data by handwriting, e.g. gesture or text

Abstract

A method of calibrating optical components in a light-based touch screen, including providing (i) a display, (ii) a row of light pulse emitters that sequentially transmit light pulses over the display according to calibrated pulse current and pulse duration controls, and (iii) a row of light pulse receivers that receive the light pulses and that output values representing the received light pulses, each receiver having expected values for emitter-receiver pairs when the light pulses are not blocked, determining if each receiver output value for a receiver-emitter pair is within a respective designated range from the corresponding receiver expected value, and when a receiver output value for a receiver-emitter pair is outside the designated range, recalibrating the emitter, including adjusting at least one of the emitter pulse current and pulse duration such that subsequent receiver output values are within the designated range, and updating the receiver expected value for the receiver-emitter pair based on subsequent output values of the receiver.

Claims

1. A method of calibrating optical components in a light-based touch screen, comprising:

providing (i) a display, (ii) a row of light pulse emitters, denoted E, that sequentially transmit light pulses over the display according to their calibrated pulse current or pulse duration controls, and (iii) a row of light pulse receivers, denoted R, that receive the sequence of light pulses transmitted by the emitters and that sequentially generate output values quantifying their received light pulses, each emitter-receiver pair (E, R) having an expected output for receiver R of the pair when the light pulses transmitted by emitter E of the pair are not blocked by an object touching the display;

determining if the actual output value for receiver R′

of a specific non-blocked pair (E′

, R′

) is outside a designated range from the expected output for (E′

, R′

);

conditional upon said determining being affirmative, further determining if the actual output values of receivers R″

of non-blocked pairs (E″

, R″

) other than (E′

, R′

) vary among themselves by less than an expected noise level for a number, N, of output values over time, where N is at least two; and

conditional upon said further determining being affirmative, recalibrating emitter E′

, comprising adjusting at least one of the pulse current and pulse duration for emitter E′

such that subsequent actual output values for receiver R′

are within the designated range.

2. The method of claim 1 further comprising additionally determining that light pulses transmitted by the emitters E″

and received by the receivers R″

are not being blocked by an object touching the display, and wherein said recalibrating is performed conditional upon said additionally determining being affirmative.

3. The method of claim 2, wherein said additionally determining comprises:

comparing deviations between actual output values for receivers R″ and

corresponding expected outputs for (E″

, R″

); and

ignoring deviations that are caused by mechanical effects that do not block light pulses.

4. The method of claim 3 wherein said ignoring comprises ignoring deviations caused by mechanical effects that are members of the group consisting of bending the device, twisting the device and flexing the display.

5. The method of claim 1 wherein said further determining comprises ignoring actual receiver output values that vary by more than the expected noise level unless two successive actual receiver output values vary by more than the expected noise level.

6. A method of calibrating a light-based touch screen, comprising:

providing (i) a display, (ii) a row of light pulse emitters, denoted E, that sequentially transmit calibrated light pulses over the display, and (iii) a row of light pulse receivers denoted R, that receive the sequence of light pulses transmitted by the emitters E and that sequentially generate output values quantifying their received light pulses, each emitter-receiver pair (E, R) having an expected output for receiver R of the pair when the light pulses transmitted by emitter E of the pair are not blocked by an object touching the display;

determining if at least one pair (E′

, R′

) detects an object touching the display that partially blocks the light pulses transmitted by emitter E′

from reaching receiver R′

, based on deviations between actual output values of receiver R′

, and the expected output for (E′

, R′

);

conditional upon said determining being affirmative, further determining if the actual output values of receivers R″

of the pairs (E″

, R″

) that do not detect the object touching the display vary among themselves by less than an expected noise level for a number, N, of output values over time, where N is at least two; and

conditional upon said further determining being affirmative, updating the expected outputs for (E″

, R″

), based on actual output values of receivers R″

.

7. The method of claim 6 further comprising additionally determining if actual receiver output values for the receivers R″

are within a designated range of the respective expected outputs for (E″

, R″

), and wherein said updating is performed conditional upon said additionally determining being affirmative.

8. The method of claim 6 wherein said determining comprises ignoring deviations between actual output values for receiver R′

and the expected output for (E′

, R′

), when the deviations are caused by mechanical effects.

9. The method of claim 8 wherein said ignoring comprises ignoring deviations caused by mechanical effects that are members of the group consisting of bending the device, twisting the device and flexing the display.

10. The method of claim 6 wherein said further determining comprises ignoring actual receiver output values that vary by more than the expected noise level unless two successive actual receiver output values vary by more than the expected noise level.

11. A method of calibrating a light-based touch screen, comprising:

providing (i) a display, (ii) a row of light pulse emitters, denoted E, that sequentially transmit calibrated light pulses over the display, and (iii) a row of light pulse receivers, denoted R, that receive the sequence of light pulses transmitted by the emitters and that sequentially generate output values quantifying their received light pulses, each emitter-receiver pair (E, R) having an expected output for receiver R of the pair when the light pulses transmitted by emitter E of the pair are not blocked by an object touching the display;

determining if light pulses transmitted by emitter E′

of a specific pair (E′

, R′

) are not being blocked from reaching receiver R′

by an object touching the display;

conditional upon said determining being affirmative, further determining if the actual output values of receiver R′

vary among themselves by less than an expected noise level for a number, N, of output values over time, where N is at least two; and

conditional upon said further determining being affirmative, updating the expected values for output for (E′

, R′

) based on actual output values of receiver R′

.

12. The method of claim 11 further comprising additionally determining that actual output values for receiver R′

are within a designated range of the expected output for (E′

, R′

), and wherein said updating is performed conditional upon said additionally determining being affirmative.

13. The method of claim 11 wherein said determining comprises:

comparing deviations between actual output values of receivers R″

of pairs (E″

, R″

) that neighbor (E′

, R′

) and the corresponding expected outputs of (E″

, R″

); and

,

ignoring deviations that are caused by mechanical effects.

14. The method of claim 13 wherein said ignoring comprises ignoring deviations caused by mechanical effects that are members of the group consisting of bending the device, twisting the device and flexing the display.

15. The method of claim 11 wherein said further determining comprises ignoring actual receiver output values that vary by more than the expected noise level unless two successive actual receiver output values vary by more than the expected noise level.