Display apparatuses and methods of operating the same
Provided are display apparatuses and methods of operating the same. In a display apparatus, a display image may be continuously held for longer than about 10 msec after the power of the display panel is turned off. The display apparatus may indicate a liquid crystal display (LCD) apparatus including an oxide thin film transistor (TFT). Off leakage current of the oxide TFT may be less than about 10 −14 A.
1. A display apparatus comprising:
a first substrate including, a TFT (thin film transistor) and a pixel electrode connected to the TFT, wherein the TFT is configured to maintain a display image for longer than 10 ms after switching to an off-state, an off-state leakage current of the TFT is less than 10 −14 A, and the display apparatus has a voltage holding time (VHT) exceeding 10 ms;
a second substrate including a common electrode facing the first substrate; and
a liquid crystal layer between the first substrate and the second substrate.
2. The display apparatus of claim 1 , wherein an off-state leakage current of the TFT is less than 10 −17 A.
3. The display apparatus of claim 1 , wherein the TFT is an oxide TFT.
4. The display apparatus of claim 3 , wherein a channel layer of the TFT includes one of a ZnO-based material, an InO-based material and a SnO-based material.
5. The display apparatus of claim 1 , wherein the TFT is an enhancement mode TFT.
6. The display apparatus of claim 1 , wherein the TFT is a depletion mode TFT.
7. The display apparatus of claim 1 , wherein the display apparatus is one of a transmissive type, a reflective type, and a transflective type.
8. The display apparatus of claim 1 , further comprising:
a capacitor on the first substrate, the capacitor including at least two capacitive structures,
wherein the display apparatus is configured to maintain a charge on the capacitor for longer than 10 ms after the TFT is switched to the off-state.
9. The display apparatus of claim 1 , wherein the TFT is one of a bottom gate TFT, a top gate TFT and a dual gate TFT.
10. A digital picture frame, comprising the display apparatus of claim 1 .
11. Electronic paper (e-paper), comprising the display apparatus of claim 1 .
12. A method of displaying an image using the display apparatus of claim 1 , the method comprising:
applying a voltage between the pixel electrode and the common electrode by turning on the TFT; and
turning off the TFT.
13. The method of claim 12 , further comprising:
maintaining the image by performing a refresh operation to the TFT in an off-state, the refresh operation including re-applying the voltage.
14. The method of claim 12 , wherein turning off the TFT includes applying one of a negative (−) voltage and about 0 volts.
15. The method of claim 12 , wherein turning off the TFT includes biasing the TFT to an off-state leakage current of less than 10 −14 A.
16. The method of claim 12 , wherein the TFT is an oxide TFT.
17. The method of claim 16 , wherein a channel layer of the TFT includes one of a ZnO-based material, an InO-based material and a SnO-based material.
18. The method of claim 12 , wherein the display apparatus is a digital picture frame.
19. The method of claim 12 , wherein the display apparatus is an electronic paper (e-paper).
20. The display apparatus of claim 1 , wherein the TFT is configured to maintain a display image for longer than or equal to 10 2 sec after switching to an off-state.