Display apparatuses and methods of operating the same

• US 8,610,652 B2
• Filed: 07/08/2009
• Issued: 12/17/2013
• Est. Priority Date: 12/12/2008
• Status: Expired due to Fees

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Lee, Sung-hoon, Kim, Do-hyun, Kim, Sang-wook, Kim, Chang-jung
• Primary Examiner(s): Sitta, Grant
• Application Number:
  US12/458,312
• Publication Number:
  US 20100149138A1
• Time in Patent Office: 1,623 Days
• Field of Search: 345/204, 345/87, 349/43, 257/59, 257/43, 257/57, 257/66, 257/72, 257/347
• US Class Current: 345/87
• CPC Class Codes: G02F 1/1368 in which the switching element is a three-electrode device G02F1/136277 takes precedence
• CPC Class Codes: G09G 2330/027 Arrangements or methods related to powering off a display
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence

Abstract

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.

Claims

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<sup>−

14</sup> 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 10² sec after switching to an off-state.