Display device dedicated to proximity detection
View Patent ↗The invention pertains to a display device, the surface of the device being rendered touch-sensitive, the device comprising a first dedicated part comprising two insulating plates, a layer of material exhibiting electro-optical properties suitable for rendering all or part of its surface visible under the effect of an electrical control signal, the layer being disposed between the two plates, at least one first electrode having the shape of a pictogram, the first electrode being disposed on a face of one of the insulating plates, a second electrode disposed on a face of the other insulating plate opposite at least one first electrode. According to the invention, the second electrode is used as responsive element of the touch-sensitive surface of the device, the surface area of the second electrode is at least 9 mm 2 , and the surface area of the second electrode is greater than the surface area or the sum of the surface areas of the first electrode or electrodes opposite.
1. A display device, a surface of the device being rendered touch-sensitive, the device comprising:
a first dedicated part having two insulating plates;
a layer of material exhibiting electro-optical properties suitable for rendering all or part of a surface of the layer of material visible under the effect of an electrical control signal, the layer being disposed between inner faces of the two insulating plates;
at least one first electrode having a shape of a pictogram, the at least one first electrode being disposed on the inner face of one of the insulating plates;
a touch sensor comprising a second electrode disposed on the inner face of the other insulating plate opposite the at least one first electrode, wherein
the electrical control signal is applied between the at least one first electrode and the second electrode, and a touch sensor signal distinct from the electrical control signal is also applied to the second electrode, the touch sensor signal is configured to enable proximity detection of a finger by capacitive effect;
a surface area of the second electrode is at least 9 mm 2 , and
the surface area of the second electrode is greater than or equal to the surface area or the sum of the surface areas of the at least one first electrode.
2. The device as claimed in claim 1 , wherein the at least one first electrode is fed electrically by a pad in that the second electrode is profiled opposite the pad.
3. The device as claimed in claim 2 , further comprising several second electrodes, and in that each second electrode is fed separately.
4. The device as claimed in claim 2 , wherein a pattern of the second electrode covers substantially a circle of at least 9 mm in diameter.
5. The device as claimed in claim 2 , further comprising a second non-dedicated part.
6. The device as claimed in claim 1 , wherein the device comprises several second electrodes, and in that each second electrode is fed separately.
7. The device as claimed in claim 6 , wherein a pattern of the second electrode covers substantially a circle of at least 9 mm in diameter.
8. The device as claimed in claim 6 , further comprising a second non-dedicated part.
9. The device as claimed in claim 1 , wherein a pattern of the second electrode covers substantially a circle of at least 9 mm in diameter.
10. The device as claimed in claim 9 , further comprising a second non-dedicated part.
11. The device as claimed in claim 1 , further comprising a second non-dedicated part.
12. The device as claimed in claim 11 , wherein the second non-dedicated part is arranged in the form of a matrix with row-wise and column-wise addressing.
13. The device as claimed in claim 1 , wherein the electrical control signal is a low frequency signal and the touch sensor signal is a high frequency signal.
14. The device as claimed in claim 1 , wherein the electrical control signal is a low frequency signal of about 100 Hz and the touch sensor signal is a high frequency signal of about 2 MHz.
15. The device as claimed in claim 1 , wherein application of a high frequency touch sensor signal, onto the second electrode, enables detection of the finger by analyzing a change in the high frequency touch sensor signal in the second electrode due to an existence of a capacitance created between the finger and the second electrode.