Liquid crystal display device

1. A liquid crystal display device, being configured such that at least one internal power supply, which is a power supply for driving gate lines of a display part in the liquid crystal display device, is automatically changed, using a power supply changeover circuit, from a first power supply, which includes a luminance inclination circuit, to a second power supply, which includes a power holding circuit, and which is different from the first power supply, when an input power supply fed to the liquid crystal display device is cut off, wherein said first power supply and said second power supply are connected in parallel and further wherein said power supply changeover circuit directly detects the cut off of the input power supply,

wherein, after the input power supply is cut off, a voltage based on said second power supply is outputted to all gate signal lines of the display part.

2. The liquid crystal display device according to claim 1 ,

wherein a voltage of said first power supply changes with time, and

wherein a voltage of said second power supply is attenuated according to a power outputted as the internal power supply.

3. The liquid crystal display device according to claim 1 ,

wherein a voltage of said first power supply lowers every constant period and thereafter, returns to an original voltage, and

wherein a voltage of said second power supply is kept substantially constant.

4. The liquid crystal display device according to claim 1 ,

wherein said power holding circuit is configured to hold a power fed by the input power supply, and

wherein said second power supply uses the power held in said power holding circuit.

5. The liquid crystal display device according to claim 4 , wherein as said second power supply, residual charges in said power holding circuit are utilized.

6. The liquid crystal display device according to claim 1 , wherein said internal power supply is a gate-on power supply involved in driving control of the gate signal line of the display part.

7. The liquid crystal display device according to claim 1 , wherein said liquid crystal display device is a reflective liquid crystal display device.

8. The liquid crystal display device according to claim 1 , wherein said liquid crystal display device is a transfiective liquid crystal display device.

9. The liquid crystal device according to claim 1 , wherein said power supply changeover circuit includes a plurality of resistors and a plurality of transistors.

10. The liquid crystal device according to claim 9 , wherein said plurality of transistors includes two n-channel transistors and one p-channel transistor.

11. The liquid crystal display device according to claim 1 , wherein a waveform of an output driving voltage of said first power supply includes intentionally blunt falling edges.

12. A liquid crystal display device, comprising:

a first power supply circuit configured to generate a first power supply from an input power supply fed to the liquid crystal display device, wherein said first power supply circuit includes a luminance inclination circuit;

a second power supply circuit configured to generate from the input power supply a second power supply different from the first power supply, wherein said second power supply circuit and said first power supply circuit are connected in parallel and further wherein said second power supply circuit includes a power holding circuit; and

a power supply changeover circuit configured to selectively output, as an internal power supply, one of the first power supply generated in said first power supply circuit and the second power supply generated in said second power supply circuit, wherein said internal supply is a power supply for driving gate lines of a display part in the liquid crystal display device, and further wherein said power supply changeover circuit directly detects a cut off of the input power supply.

13. The liquid crystal display device according to claim 12 , wherein said power supply changeover circuit automatically changes the power supply to be outputted as the internal power supply from the first power supply to the second power supply when the input power supply is cut off.

14. The liquid crystal display device according to claim 12 , wherein said power supply changeover circuit changes the power supply to be outputted as the internal power supply according to a voltage of the input power supply.

15. The liquid crystal display device according to claim 12 , wherein the internal power supply is a power supply for driving the gate signal line of the display part.

16. The liquid crystal display device according to claim 15 ,

wherein said first power supply circuit generates a voltage waveform for reducing luminance unevenness in a direction in which the gate signal line of the display part extends, and

wherein said second power supply circuit generates a voltage waveform whose voltage is constant.

17. The liquid crystal display device according to claim 12 ,

wherein said first power supply circuit generates the first power supply whose voltage is changed based on an inputted oscillation signal, and

wherein said second power supply circuit holds a power by the input power supply to generate the second power supply.

18. The liquid crystal display device according to claim 12 , further comprising:

a gate driving circuit configured to be fed with the internal power supply to drive the gate signal line of the display part,

wherein said gate driving circuit sequentially outputs signals generated using the first power supply to the gate signal lines, and when the input power supply is cut off, said gate driving circuit outputs a voltage of the second power supply to all the gate signal lines.

19. The liquid crystal device according to claim 2 , wherein said power supply changeover circuit includes a plurality of resistors and a plurality of transistors.

20. The liquid crystal device according to claim 19 , wherein said plurality of transistors includes two n-channel transistors and one p-channel transistor.

21. The liquid crystal display device according to claim 12 , wherein a waveform of an output driving voltage of said first power supply includes intentionally blunt falling edges.

22. A liquid crystal display device comprising:

a luminance inclination circuit configured to generate, from an input power supply fed to the liquid crystal display device, a voltage waveform for reducing luminance unevenness in a direction in which a gate signal line of a display part extends;

a power holding circuit configured to hold a power by the input power supply, wherein said power holding circuit and said luminance inclination circuit are connected in parallel;

a power supply changeover circuit configured to selectively output one of an output from said luminance inclination circuit and an output from said power holding circuit according to a voltage of the input power supply, wherein said power supply changeover circuit directly detects a cut off of the input power supply; and

a gate driving circuit configured to be fed with an output of said power supply changeover circuit to drive the gate signal line of the display part.

23. The liquid crystal display device according to claim 22 , wherein said power supply changeover circuit outputs an output from said luminance inclination circuit when a voltage value of the input power supply is higher than a threshold value, and outputs an output from said power holding circuit when the voltage value of the input power supply is equal to or lower than the threshold value.

24. The liquid crystal device according to claim 22 , wherein said power supply changeover circuit includes a plurality of resistors and a plurality of transistors.

25. The liquid crystal device according to claim 24 , wherein said plurality of transistors includes two n-channel transistors and one p-channel transistor.

26. The liquid crystal display device according to claim 22 , wherein a waveform of an output driving voltage of said first power supply includes intentionally blunt falling edges.