Display arrangement and method
A display arrangement comprises a thin film display element comprising a first patterned conductor layer, comprising a first display electrode, on a first side of an emissive layer; a second patterned conductor layer, comprising a second display electrode, on a second side of the emissive layer opposite the first side; and a touch-sensing element comprising first and second touch electrodes formed in the first and second patterned conductor layers, respectively. The display arrangement further comprises a control unit configured to measure capacitive coupling for at least one of the touch electrodes, said measuring comprising supplying a measurement volt age signal to the touch-sensing element, and, when supplying the measurement voltage signal to one touch electrode, to supply a shielding voltage signal to the other touch electrode to decrease an effect of a touch from the side of said other touch electrode on the capacitive coupling for said one touch electrode.
1. A display arrangement comprising a transparent thin film display element with a layer structure extending substantially along a base plane defining a lateral extension of the display element, the thin film display element comprising:
an emissive layer configured to emit light in consequence of electrical voltage coupled over the emissive layer;
a first patterned conductor layer, on a first side of the emissive layer, comprising a first display electrode;
a second patterned conductor layer, on a second side of the emissive layer opposite the first side, comprising a second display electrode at least partly laterally overlapping the first display electrode; and
a touch-sensing element comprising a first touch electrode and a second touch electrode formed in the first and second patterned conductor layers, respectively,
wherein the display arrangement further comprises a control unit configured to measure touch-dependent capacitive coupling for at least one of the first and second touch electrodes, said measuring comprising supplying a time-dependent measurement voltage signal to the touch-sensing element, and, when supplying the measurement voltage signal to the touch-sensing element for measuring the touch-dependent capacitive coupling for one of the first and second touch electrodes, to supply a shielding voltage signal to the other touch electrode to decrease an effect of a touch from the side of said other touch electrode on the touch-dependent capacitive coupling for said one touch electrode,
wherein a signal cross-correlation coefficient c s between the measurement voltage signal and the shielding voltage signal is at least 0.8.
2. A display arrangement according to claim 1 , wherein the control unit is configured to measure touch-dependent capacitive coupling for each of the first and second touch electrodes.
3. A display arrangement according to claim 1 , wherein the control unit is configured, when measuring touch-dependent capacitive coupling for said one of the first and second touch electrodes, to supply the measurement voltage signal to said one touch electrode, said touch-dependent capacitive coupling being indicative of a self-capacitance of said one touch electrode.
4. A display arrangement according to claim 1 , wherein the touch-sensing element comprises a transmitter electrode in the first and/or the second patterned conductor layer and the control unit is configured, when measuring touch-dependent capacitive coupling for said one of the first and second touch electrodes, to supply the measurement voltage signal to the transmitter electrode, said touch-dependent capacitive coupling being indicative of a mutual capacitance between the transmitter electrode and said one touch electrode.
5. A display arrangement according to claim 1 , wherein the first and second touch electrodes at least partly laterally overlap each other.
6. A display arrangement according to claim 5 , wherein the first and second touch electrodes laterally overlap each other in an overlapping region and an overlapping ratio between an area of the overlapping region and an area of a union of projections of the first and second touch electrodes on the base plane is at least 0.5.
7. A display arrangement according to claim 1 , wherein an amplitude ratio between highest peak-to-peak amplitudes of the measurement voltage signal and the shielding voltage signal is in a range from 0.8 to 1.2.
8. A display arrangement according to claim 1 , wherein the thin film display element is implemented as a segment-type display element.
9. A display arrangement according to claim 1 , wherein the thin film display element is implemented as an inorganic thin film electroluminescent, TFEL, display element.
10. A display arrangement according to claim 1 , wherein the thin film display element is implemented as a thin film organic light emitting diode, OLED, display element.
11. A double-sided display panel comprising a display arrangement according to claim 1 .
12. A window assembly comprising a display arrangement according to claim 1 .
13. A method for touch detection using a thin film display element in accordance with claim 1 , the method comprising:
measuring touch-dependent capacitive coupling for at least one of the first and the second touch electrodes, said measuring comprising supplying a time-dependent measurement voltage signal to the touch-sensing element; and
when supplying the measurement voltage signal to the touch-sensing element for measuring the touch-dependent capacitive coupling for one of the first and the second touch electrodes, supplying a shielding voltage signal to the other touch electrode to decrease an effect of a touch from the side of said other touch electrode on the touch-dependent capacitive coupling for said one touch electrode.
14. A method according to claim 13 , comprising measuring touch-dependent capacitive coupling for each of the first and second touch electrodes.
15. A method according to claim 13 , wherein each touch-dependent capacitive coupling is indicative of a self-capacitance of a touch electrode.
16. A method according to claim 13 , wherein the touch-sensing element comprises a transmitter electrode in the first and/or the second patterned conductor layer and each touch-dependent capacitive coupling is indicative of a mutual capacitance between the transmitter electrode and a touch electrode.
17. A vehicle comprising a window assembly, the window assembly comprising a display arrangement, the display arrangement comprising a transparent thin film display element with a layer structure extending substantially along a base plane defining a lateral extension of the display element, the thin film display element comprising:
an emissive layer configured to emit light in consequence of electrical voltage coupled over the emissive layer;
a first patterned conductor layer, on a first side of the emissive layer, comprising a first display electrode;
a second patterned conductor layer, on a second side of the emissive layer opposite the first side, comprising a second display electrode at least partly laterally overlapping the first display electrode; and
a touch-sensing element comprising a first touch electrode and a second touch electrode formed in the first and second patterned conductor layers, respectively,
wherein the display arrangement further comprises a control unit configured to measure touch-dependent capacitive coupling for at least one of the first and second touch electrodes, said measuring comprising supplying a time-dependent measurement voltage signal to the touch-sensing element, and, when supplying the measurement voltage signal to the touch-sensing element for measuring the touch-dependent capacitive coupling for one of the first and second touch electrodes, to supply a shielding voltage signal to the other touch electrode to decrease an effect of a touch from the side of said other touch electrode on the touch-dependent capacitive coupling for said one touch electrode.