Display apparatus and method for operating a display apparatus

• US 20080238871A1
• Filed: 03/28/2008
• Published: 10/02/2008
• Est. Priority Date: 03/30/2007
• Status: Abandoned Application

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Tam, Simon
• Application Number:
  US12/078,277
• Publication Number:
  US 20080238871A1
• Time in Patent Office: Days
• US Class Current: 345/158
• CPC Class Codes: G02F 1/1533 structural features not otherwise provided for
• CPC Class Codes: G02F 1/163 Operation of electrochromic cells, e.g. electrodeposition cells; Circuit arrangements therefor
• CPC Class Codes: G06F 1/3218 of display devices
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/046 by electromagnetic means
• CPC Class Codes: G09G 2360/14 Detecting light within display terminals, e.g. using a single or a plurality of photosensors
• CPC Class Codes: G09G 3/20 for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
• CPC Class Codes: G09G 3/38 using electrochromic devices

Abstract

A display apparatus includes a plurality of scanning lines and data lines and, at each intersection of said data lines and scanning lines, an electrochromic pixel element and a sensor element connected to the pixel element. The sensor element is sensitive to a user'"'"'s graphical input, which changes a charge state of the respective pixel element. The display apparatus also includes a control means, which is configured to allow the pixel element to be selectively set to a first charge state corresponding to a first display state, or to a second charge state corresponding to a second display state. The second display state reflects the user'"'"'s graphical input. The second charge state of the pixels may be brought about by exposing the sensor elements to light from a light pen or to a magnetic field from a magnetic pen, the pen being drawn across the display screen of the apparatus. Due to the direct action of the sensor elements in modulating the charge on the pixel elements, it is possible to display an image drawn on the screen instantly, without the need to scan the display to determine which pixels have changed their initial charge. This reduces the power consumption of the apparatus.

Claims

1. A display apparatus comprising:

a plurality of scanning lines;

a plurality of data lines;

a plurality of electrochromic pixel elements positioned at each of the plurality of intersections of the plurality of data lines and the plurality of scanning lines;

a plurality of sensor elements connected to the plurality of electrochromic pixel elements, each of the plurality of sensor elements being sensitive to a graphical input, thereby to change a charge state of each of the plurality of electrochromic pixel elements respectively; and

a control means, which is configured to allow the plurality of electrochromic pixel element to be selectively set to a first charge state corresponding to a first display state, or to a second charge state corresponding to a second display state, the second display state reflecting the graphical input.

2. The display apparatus according to claim 1, the control means including a first switch means which is connected to one of the plurality of data lines and is configured to selectively connect the one of the plurality of data lines to an input video signal for setting the plurality of electrochromic pixel elements to the first charge state, or to a charge-sensing circuit for reading out the second charge state of the plurality of electrochromic pixel elements.

3. The display apparatus according to claim 2, the control means being configured to perform three sequential phases of operation:

a pre-charge phase, in which said first charge state of the pixel element is set;

an exposure phase, in which the sensor element is exposed to said user'"'"'s graphical input, and

a readout phase, in which said second charge state of the pixel element is read out.

4. The display apparatus according to claim 3, one end of one of the plurality of electrochromic pixel elements and one end of one of the plurality of sensor elements being electrically coupled to each other, the other end of one of the plurality of electrochromic pixel elements being electrically connected to a common voltage for all of the plurality of electrochromic pixel elements, and the other end of one of the plurality of sensor elements being electrically connected to a reference voltage.

5. The display apparatus according to claim 4, further comprising:

a second switch means electrically connected to at least one of the plurality of data lines and to at least one of the plurality of electrochromic pixel elements and controlled by a respective one of the plurality of scanning lines.

6. The display apparatus according to claim 5, the control means being configured such that:

in said pre-charge phase, said second switch means is switched on, thereby to connect said pixel element and said sensor element to said data line;

said first switch means connects said data line to said input video signal;

said input video signal is at a low voltage level;

said common voltage is at a high voltage level and said reference voltage is at a low voltage level;

in said exposure phase, said second switch means is switched off;

said common voltage is at said high voltage level;

said input video signal is at said low voltage level, and said reference voltage is a high voltage level; and

in said readout phase, said common voltage is at a low voltage level, said reference voltage is at a low voltage level, and said first switch means connects said data line to an input of said charge-sensing circuit.

7. The display apparatus according to claim 6, the charge-sensing circuit being an integrator and the control means being configured to reset the integrator during an initial part of the readout phase.

8. The display apparatus according to claim 5, further comprising:

a third switch means interposed between at least one of the plurality of electrochromic pixel elements and at least one of the plurality of sensor elements.

9. The display apparatus according to claim 8, the control means being configured to control the third switch means so as to allow at least one of the plurality of sensor elements to be electrically connected to one of the plurality of data lines only during the exposure phase.

10. The display apparatus according to claim 1, each of the plurality of sensor elements being a light-sensitive element.

11. The display apparatus according to claim 10, the light-sensitive element being a photo-conductor element or a photo-diode.

12. The display apparatus according to claim 10, further comprising:

a light pen for entering the graphical input.

13. The display apparatus according to claim 1, each of the plurality of sensor elements being a magnetic-field sensitive element.

14. The display apparatus according to claim 13, the magnetic-field sensitive element being a magnetoresistive element.

15. The display apparatus according to claim 13, further comprising:

a magnetic pen for entering the graphical input.

16. The display apparatus according to claim 1, each of the plurality of sensor elements being a pressure-sensitive element, the graphical image being configured to be entered by the exertion of pressure.

17. The display apparatus according to claim 6, further comprising:

a fourth switch means for triggering the start of the exposure phase.

18. The display apparatus according to claim 17, further comprising:

a fifth switch means for triggering the start of the pre-charge phase.