Excellence in Electronics Distribution Logistics Programming Development A Touch of Magic User Interface Design, Eindhoven, 6 februari 2013. Gerrit-Jan van Os / MSC-GE
MSC Atmel QTouch/QMatrix 12-2011 2 MSC Gleichmann Electronics Over 1500 employees R&D, 150 engineers in e.g. Stutensee, Neufahrn Production in e.g. Stutensee, Freiburg, China
Display Search indentifies 11 categories of touch screens 1/2
Display Search indentifies 11 categories of touch screens 2/2
Non-Capacitive Touch sensors
Why Projected Capacitive Touch? Resistive screen - Tends to collect dust and dirt - Added cost to make waterproof - Custom button shapes add cost Infrared screen - Weak mechanical performance - Membrane wears down and cracks - Sensitivity decreases Capacitive screens - Moisture resistant - Full freedom on button design - No performance degradation over time - Cost effective solution
Free Space Capacitance Model MSC Atmel QTouch/QMatrix 12-2011 7
Free Space Capacitance Model With Handheld Devices MSC Atmel QTouch/QMatrix 12-2011 8
MSC Atmel QTouch/QMatrix 12-2011 9 Theory of Capacitive Touch Finger adds capacitance to the touch sensor Change in C can be measured Multiple ways to do this All methods are capable of detecting a touch Selected technology will determine: Accuracy-over-temperature range, voltage and humidity Signal-Noise-Ratio Noise Immunity Power Consumption Moisture Tolerance Maximum overlay thickness QTouch and QMatrix are Atmel s methods for touch sensing
QMatrix - Basics MSC Atmel QTouch/QMatrix 12-2011 10
MSC Atmel QTouch/QMatrix 12-2011 11 QMatrix - Basics X0 MCU VDD S2 S4 GND X Yk Cx X1 X2 X3 S1 GND Cs Y0 S3 GND Y Sampling capacitor Y1 Vsns Vcs Approximately linear Time 0.25V t -0.25V Time Terminal voltage Vyk
MSC Atmel QTouch/QMatrix 12-2011 12 QMatrix - What Happens During Touch? A finger close to electrode diverts charge from Cx, and so away from Cs E-field X Y EARTH Vcs Vcs No touch Touch Time Time Ct So each charge pulse now charges Cs by a smaller amount This means charge builds up in Cs less quickly So if each pulse deposits less charge, then Vcs rises slower, so reaches a smaller terminal voltage needs less time to discharge to GND so counter value gets less count change (delta) is proportional to Ct Delta
MSC Atmel QTouch/QMatrix 12-2011 13 Adjacent Key Suppression For small, tightly grouped touch keys, how do we resolve which key the user meant to press? Several keys can show detection at once Cross bleed can also tend to make several keys show strong signals Adjacent Key Suppression or AKS is the way to resolve this Think of AKS like a race between all the keys in detection trying to reach the winning line first
MSC Atmel QTouch/QMatrix 12-2011 14 ATMEL Technology Advantages AKS - Adjacent Key Suppression Spread Spectrum Modulation Superior EMC and EMI behavior Auto Calibration Adjusts for temperature, humidity, component fade on every key individually Covers slow and quick moving gradients Low power operation 1.8V 5.5V, multiple sleep modes Best field penetration & SNR Works in moisture environments Ease of system design
Classes of Touch Sensors Two main classes when referring to Indium-Tin-Oxide touch screens: - PolyEThyleen based - Glass based Each of above in two sub-classes: - Single layer ITO ( up to 7 screens) - Dual layer ITO New: PolyEThyleen dual layer with nano silver.
GE-Star Touch Sensors
Projective Capacitive Touch Sensor Cover glass OCA carrier Y-layer OCA X-layer carrier Display
Foil Integration Rules Avoid air gap between touch foil and glass!!!!!!!!! maximum distance of 0,1-0,2mm Make sure only the active sensor area covers the active display area. Other sensor structures like silver print and tail must be located outside to avoid noise problems Any cover foil on top of the touch sensor or front glas must be laminated to avoid false touch detections caused by varying air gaps
Mounting Possibilities Glue the border of touch sensor with a double side 3M tape with thickness lower than 0,2mm to the frontglass (this air gap is allowed)
Mounting Possibilities Glue the touch into a frame (metal frame is also possible). Glass cover is also located inside the frame TFT is behind the frame
GE-Star Features and Benefits GE- GE-
GE-Star Touch Controllers Three controller boards available: - For screens up to 9.1, from 10.4-12.1, and from 13.3 till 22 - Respectively supporting 224, 768, and 1386 nodes - USB or RS232 interface via On-board AT90USB162 - Drivers available for WinXP, Win7, Linux, Win CE 5.0/6.0 - Touch calibration and configuration directly over the driver for all OS
GE Star Touch Supporting Software
Supporting Software
Creating and supporting solutions with our partners:
MSC Atmel QTouch/QMatrix 12-2011 26 GE-Star Touch Sensors and Controllers Bedankt voor uw aandacht! Vragen? Gerrit-Jan van Os 078 6920 152 gvos@msc-ge.com www.msc-ge.com