Display device and moving-film display device

• US 6,697,035 B2
• Filed: 03/13/2001
• Issued: 02/24/2004
• Est. Priority Date: 03/30/2000
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Itoh, Goh, Okumura, Haruhiko, Sugahara, Atsushi, Lang, Richard
• Primary Examiner(s): Saras, Steven
• Assistant Examiner(s): Anyaso, Uchendu O.
• Application Number:
  US09/804,238
• Publication Number:
  US 20010043167A1
• Time in Patent Office: 1,078 Days
• Field of Search: 340/815.83, 345/85, 345/31
• US Class Current: 345/85
• CPC Class Codes: G09G 2300/08 Active matrix structure, i.e. with use of active elements, inclusive of non-linear two terminal elements, in the pixels together with light emitting or modulating elements
• CPC Class Codes: G09G 2300/0809 Several active elements per pixel in active matrix panels
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2310/061 for resetting or blanking
• CPC Class Codes: G09G 2320/0606 Manual adjustment
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2320/066 for control of contrast
• CPC Class Codes: G09G 3/2011 by amplitude modulation
• CPC Class Codes: G09G 3/3433 using light modulating elements actuated by an electric field and being other than liquid crystal devices and electrochromic devices using liquid crystal devices G09G3/36; using electrochromic devices G09G3/38

Abstract

In a moving-film display device, each pixel includes a moving film electrode capable of bending and a counter electrode. The display color of each pixel is determined when the moving film electrode bends by a potential difference between the moving film electrode and the counter electrode. The moving film electrode is connected to a signal line via a TFT. The TFT is turned on/off by an address line. A controller keeps the TFT ON until the potential of the moving film electrode becomes substantially equal to a signal potential, and turns off the TFT before the moving film electrode comes closest to the counter electrode.

Claims

1. A moving-film display device comprising:

a pixel matrix defined by rows and columns of a plurality of pixels, each of said pixels comprising,

first and second electrodes, one of said first and second electrodes being a moving film electrode capable of bending, at least its end portion having a colored portion, the other of said first and second electrodesbeing a counter electrode which opposes said moving film electrode, and

an internal switch disposed in each of the pixels and configured to be selectively connected to said first electrode;

a plurality of signal lines, each connected to the internal switches of disposed in the pixels arranged in a row in order to supply an image signal for driving said first electrodes;

a signal line driver configured to selectively supply the image signal to said signal lines;

a plurality of counter potential lines, each connected to the second electrodes of pixels arranged in a column in order to give a counter potential to said second electrodes;

a plurality of address lines, each of the address lines supplying a control signal to said internal switches for selecting said pixels; and

a controller configured to control said signal lines, said counter potential lines, said address lines, and said internal switches;

address lines, and said internal switches;

wherein a display color of each pixel is determined when said moving film electrode bends by a potential difference between said moving film electrode and said counter electrode.

2. The device according to claim 1, wherein said controller supplies said control signal to a selected internal switch disposed in a pixel and turns off the internal switch when the potential of said first electrode becomes substantially equal to the signal potential, or when said moving film electrode comes close to said counter electrode to a predetermined distance.

3. The device according to claim 1, wherein each of said pixels further comprises a first capacitor connected to a node between said internal switch and said first electrode in order to hold the signal potential given from said signal line, said first capacitor being disposed as a capacitor different from a capacitor formed by the first and second electrodes.

4. The device according to claim 1, wherein said internal switch is a MOS transistor, a source and a drain of which are connected to said signal line and said first electrode, respectively, and having a gate connected to said address line.

5. The device according to claim 1, wherein said first electrode is said moving film electrode and said second electrode is said counter electrode.

6. The device according to claim 1, wherein said first electrode is said counter electrode and said second electrode is said moving film electrode.

7. The device according to claim 1, wherein each of said pixels further comprises a second capacitor connecting said first electrode to said internal switch.

8. The device according to claim 1, wherein each of said pixels further comprises a third electrode which opposes said moving film electrode, and the moving film electrode is disposed between the counter electrode and the third electrode.

9. The device according to claim 8, wherein said first electrode is said moving film electrode, said second electrode is said counter electrode, and said third electrode is given another counter potential different from the counter potential.

10. The device according to claim 8, wherein said first electrode is said counter electrode, said second electrode is said moving film electrode, and said third electrode is given another signal potential different from the signal potential.

11. The device according to claim 1, wherein each of said pixels further comprises an intermediate switch configured to selectively supply a writing potential to said first electrode, said intermediate switch being controlled by said image signal.

12. The device according to claim 11, wherein each of said pixels further comprises a resistor connected to a node between said intermediate switch and said first electrode.

13. The device according to claim 1, wherein said colored portion has a first color, and each of said pixels further comprises a portion which has a second color different from the first color.

20. The device according to claim 3, wherein each of said pixels further comprises a bypass resistor in parallel with said first capacitor in order to release electric charge from said first capacitor.

21. The device according to claim 20, wherein said controller applies a gradation display potential different from one pixel to another as the signal potential to perform a gradation display on the basis of an exposure/non-exposure time of said colored portion.

22. The device according to claim 21, wherein said controller divides a one-frame time, which is a display time of an image, into a reset period, writing period, and non-selection period, wherein a reset potential common to all pixels is applied as the signal potential in the reset period, the gradation display potential is applied to a pixel of interest as the signal potential in the writing period, and said internal switch of said pixel of interest is turned off in the non-selection period.

23. The device according to claim 20, wherein said resistor is a variable resistor.

14. A moving-film display device comprising a pixel matrix defined by rows and columns of a plurality of pixels disposed on an insulating substrate,

wherein each of said pixels comprises:

a semiconductor switch disposed on said substrate and electrically connected to a signal line;

an intermediate conductor plate disposed on said substrate via a first insulating layer and electrically connected to said switch;

an upper conductor plate disposed on said intermediate conductor plate via a second insulating layer, said intermediate conductor plate and said upper conductor plate being electrically coupled with each other; and

a pair of electrodes including first and second electrodes which oppose each other while standing on said second insulating layer, said first electrode being electrically connected to said upper conductor plate, said second electrode being given a counter potential, one of said first and second electrodes being a moving film electrode which has a colored portion in an upper end portion and can bend, the other one of said first and second electrodes being a counter electrode which opposes said moving film electrode, and a display color of each pixel being determined when said moving film electrode bends by a potential difference between said moving film electrode and said counter electrode.

15. The device according to claim 14, further comprising, in each of said pixels, a third electrode as another counter electrode which opposes said moving film electrode while standing on said second insulating layer, wherein said moving film electrode is placed between the two counter electrodes.

16. The device according to claim 15, wherein said first electrode is said moving film electrode, said second electrode is said counter electrode, and said third electrode is given another counter potential different from the counter potential.

17. The device according to claim 15, wherein said first electrode is said counter electrode, said second electrode is said moving film electrode, said third electrode is given another signal potential different from the signal potential, and another semiconductor switch, another intermediate conductor plate, and another upper conductor plate equivalent to said semiconductor switch, said intermediate conductor plate, and said upper conductor plate, respectively, are disposed for said third electrode in order to give the another signal potential to said third electrode.

18. The device according to claim 14, wherein said intermediate conductor plate and said upper conductor plate are electrically connected via a connecting conductor embedded in said second insulating layer.

19. The device according to claim 18, wherein said substrate and said intermediate conductor plate are transparent to light selected from the group consisting of visible light and ultraviolet light, said second insulating layer is made of an ultraviolet-curing resin, and said connecting conductor comprises metal pieces dispersed in said second insulating layer.

24. A display device comprising:

a pixel matrix defined by rows and columns of a plurality of pixels, each of said pixels comprising a pair of electrodes including first and second electrodes opposing each other, and a colored portion which determines a display color of said pixel by changing an exposed state thereof in accordance with a potential difference between said pair of electrodes;

a plurality of signal lines which run along said pixels to give said first electrode a signal potential as an image signal;

a counter potential line disposed to give a counter potential to said second electrode;

a capacitor so disposed in each of said pixels as to connect a node between said signal line and said first electrode to a constant-potential portion different from said second electrode, in order to hold the signal potential given from said signal line;

a bypass formed in each of said pixels and including a resistor connected to said node in parallel with said capacitor in order to release electric charge from said capacitor;

a signal line driver configured to selectively supply the image signal to said signal lines; and

a controller configured to control said signal line driver, said controller applying a gradation display potential different from one pixel to another as the signal potential in order to perform a gradation display on the basis of an exposure/non-exposure time of said colored portion.

25. The device according to claim 24, wherein said controller divides a one-frame time of the image signal into a reset period, writing period, and non-selection period, applies to a pixel of interest a reset potential common to all pixels as the signal potential in the reset period, applies to said pixel of interest the gradation display potential as the signal potential in the writing period, and does not apply the signal potential to said pixel of interest in the non-selection period.

26. The device according to claim 24, further comprising:

a switch so disposed in each of said pixels as to connect said first electrode to said signal line, in order to selectively connect said first electrode to said signal line;

a plurality of address lines which run along said pixels to give said switches an ON/OFF control potential as an address signal for selecting said pixels; and

an address line driver controlled by said controller to selectively supply an address signal to said address lines.

27. The device according to claim 24, wherein a resistance value of said resistor is variable.

28. The device according to claim 24, wherein one of said first and second electrodes is a moving film electrode capable of bending, the other one of said first and second electrodes is a counter electrode which opposes said moving film electrode, said colored portion changes an exposed state thereof in accordance with bending of said moving film electrode, and a display color of each pixel is determined when said moving film electrode bends by a potential difference between said moving film electrode and said counter electrode.