ASIC CONTROLLER FOR LIGHT-BASED SENSOR

• US 20150277666A1
• Filed: 04/30/2015
• Published: 10/01/2015
• Est. Priority Date: 11/02/2001
• Status: Active Grant

• Current Assignee: Neonode, Inc.
• Original Assignee: Neonode, Inc.
• Inventors: Jansson, Anders, Goertz, Magnus, Eriksson, Thomas, Shain, Joseph, Kvist, Niklas, Pettersson, Robert, Sparf, Lars, Karlsson, John
• Granted Patent: US 9,778,794 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• 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 3/0421 by interrupting or reflecting a light beam, e.g. optical touch-screen

Abstract

A state machine for controlling a sensor including a chip package coupled with photo-emitters and photo-detectors mounted in a device, and with a host processor, including an emitter driver, a detector driver, a signal processor for generating signals representing amounts of light detected by the detectors, and a scan controller for controlling the emitter and detector drivers to activate an automated sequence of emitter-detector pairs, the scan controller including registers for storing parameters designating emitter-detector pairs that are to be activated during the automated sequence, and for storing the signals generated by the signal processor for the emitter-detector pair activations, and at least one input/output pin for receiving parameters from the host processor to be loaded into the registers, and for outputting the stored signals in the registers to the host processor, for the host processor to identify therefrom location coordinates of an object near or touching the device.

Claims

1-21. -21. (canceled)

22. A programmable state machine for controlling a light-based sensor comprising:

a chip package coupled with photo-emitters and photo-detectors mounted in a device outside of the chip package, and with a host processor, the chip package comprising;

an emitter driver for selectively activating the emitters;

a detector driver for selectively activating the detectors;

a signal processor for generating detection signals representing amounts of light detected by the detectors; and

a scan controller for controlling said emitter and detector drivers to activate an automated sequence of a plurality of emitter-detector pairs, the scan controller comprising registers for storing, prior to executing the automated sequence, parameters designating a scan sequence of emitter-detector pairs that are to be activated during the automated sequence, and for storing the detection signals generated by said signal processor for the emitter-detector pair activations;

a plurality of signal conducting pins for connecting the emitters to said emitter driver, and for connecting the detectors to said detector driver and to said signal processor; and

at least one input/output pin for receiving parameters from the host processor to be loaded into said registers, and for outputting the stored detection signals in said registers to the host processor, for the host processor to identify therefrom location coordinates of an object near or touching the device.

23. The programmable state machine of claim 22, wherein said scan controller is operable to activate first and second low-resolution automated sequences that employ the same scan sequence of emitters, and pair each activated emitter with a first respective detector during the first low-resolution automated sequence, and pair each activated emitter with a second respective detector, different than the first respective detector, during the second low-resolution automated sequence.

24. The programmable state machine of claim 23, wherein the emitters and detectors are arranged such that beams emitted from a same emitter are detected by two detectors, and wherein the first and second low-resolution automated sequences alternately pair one or the other of the two detectors with the same emitter.

25. The programmable state machine of claim 22, wherein said scan controller is operable to activate low-resolution and high-resolution automated sequences, wherein the low-resolution automated sequence pairs one respective emitter with each detector, and the high-resolution automated sequence pairs two respective emitters with each detector.

26. The programmable state machine of claim 25, wherein the emitters and detectors are arranged such that beams emitted from two emitters are detected by a same detector, wherein the low-resolution automated sequence pairs one of the two emitters with that same detector, and wherein the high-resolution automated sequence pairs both of the two emitters with that same detector.

27. A touch screen comprising the programmable state machine of claim 25, the emitters, the detectors and the host processor, wherein said host processor loads said registers to configure the low-resolution automated sequence when it does not detect a touch, and loads said registers to configure the high-resolution automated sequence when it does detect a touch.

28. The programmable state machine of claim 22, wherein a first and a last one of the detectors along an edge of the device are paired with only one emitter, and the other detectors are paired with more than one emitter, during the automated sequence.

29. The programmable state machine of claim 28, wherein the automated sequence comprises two automated high-resolution sub-sequences, each high-resolution sub-sequence activating emitters along a different edge of the device, and wherein a first and a last one of the detectors along each edge are paired with only one emitter, and the other detectors along the edge are paired with more than one emitter.

30. The programmable state machine of claim 22, wherein said signal processor comprises:

an amplifier for amplifying the detection signals; and

an analog-to-digital controller (ADC) for digitizing the amplified detection signals,

and wherein said scan controller conserves power by deactivating said amplifier and said ADC between detector activations, during the automated sequence.

31. The programmable state machine of claim 22, wherein the host processor enhances a signal-to-noise ratio for the identified location coordinates based on statistics from multiple iterations of activating the emitter-detector pairs for each identified location.

32. The programmable state machine of claim 22, wherein the automated sequence activates each of the plurality of detectors at least twice:

once during activation of an emitter, and once not during activation of an emitter to detect an ambient light value, and wherein said signal processor subtracts the detected ambient light value from a detection value of the detector during activation of an emitter.

33. The programmable state machine of claim 22, wherein said emitter driver comprises a programmable current source, for driving the emitters.

34. The programmable state machine of claim 33, wherein said registers store parameters indicating respective amounts of current for each emitter activation in the automated sequence.

35. The programmable state machine of claim 33, wherein said registers store parameters indicating respective pulse durations for each emitter activation in the automated sequence.

36. A touch screen comprising the programmable state machine of claim 22, the emitters, the detectors and the host processor.

37. The touch screen of claim 36, wherein said host processor temporally filters detected location coordinates with a filter that assigns less weight to earlier detection signals when the object is moving than when the object is stationary.

38. The touch screen of claim 36, wherein said host processor temporally filters detected location coordinates with a filter that assigns less weight to earlier detection signals when the object is moving quickly than when the object is moving slowly.

39. The touch screen of claim 36, wherein said host processor temporally filters detected location coordinates with a filter that assigns less weight to earlier detection signals when a contact area between the object and the device is small than when the contact area is large.

40. A touch screen, comprising first and second programmable state machines, each in accordance with claim 22, the emitters, the detectors and the host processor, wherein said programmable state machines are connected to respective first and second subsets of the emitters and the detectors, receive the scan sequence parameters from said host processor, activate the respective first and second subsets of the emitters and the detectors in accordance with the scan sequence parameters, and store detector output values.

41. The touch screen of claim 40, wherein the first and second subsets are such that a detector belongs to both subsets and receives light from a first emitter belonging to the first subset and also from a second emitter belonging to the second subset, and wherein the detector output values for detected light emitted by the first emitter are stored by said first programmable state machine and the detector output values for detected light emitted by the second emitter are stored by said second programmable state machine.

42. The state machine of claim 22, wherein the parameters comprise indices of an emitter and N detectors, for N initial emitter-detector pairs in the automated sequence, a step value to increment the indices of the emitter and the N detectors for each successive N emitter-detector pairs in the automated sequence, and a total number of emitters to be activated in the automated sequence, where N is a number greater than or equal to one.

43. The programmable state machine of claim 22 whereby the emitters are mounted along at least two edges of the device and the detectors are mounted along edges opposite the at least two edges, and wherein the automated sequence comprises automated sub-sequences for each of the at least two edges.

44. The state machine of claim 43, wherein the parameters comprise, for each edge of the at least two edges, indices of an emitter along that edge and N detectors, for N initial emitter-detector pairs in the automated sub-sequence for that edge, a step value to increment the indices of the emitter and the N detectors for each successive N emitter-detector pairs in the automated sub-sequence for that edge, and a total number of emitters to be activated in the automated sub-sequence for that edge, where N is a number greater than or equal to one.