Micromechanical displays and fabrication method

• US 6,323,834 B1
• Filed: 10/08/1998
• Issued: 11/27/2001
• Est. Priority Date: 10/08/1998
• Status: Expired due to Term

• Current Assignee: GlobalFoundries, Inc.
• Original Assignee: International Business Machines Corporation
• Inventors: Colgan, Evan G., Rosenbluth, Alan E., Kosbar, Laura L.
• Primary Examiner(s): Hjerpe, Richard
• Assistant Examiner(s): LESPERANCE, JEAN E
• Application Number:
  US09/168,456
• Time in Patent Office: 1,146 Days
• Field of Search: 345/90, 345/92, 345/96, 345/97, 345/98, 345/85, 345/84
• US Class Current: 345/84
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: G09G 2300/0473 Use of light emitting or modulating elements having two or more stable states when no power is applied
• 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 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
• CPC Class Codes: G09G 3/346 based on modulation of the reflection angle, e.g. micromirrors micromirrors devices per se G02B26/0833
• CPC Class Codes: Y10S 359/90 Methods

Abstract

A display device, in accordance with the present invention includes a transparent substrate and an array of pixels formed on the substrate, each pixel comprises a transparent electrode and a deformable member electrically actuated between a first state and a second state, wherein in the first state a liquid including a dye is disposed in a gap between the transparent electrode and the deformable member and wherein in the second state the deformable member reduces the gap between the transparent electrode and the deformable member such that the liquid is substantially removed between the deformable layer and the transparent electrode in the area of contact. A plurality of switches are formed on the substrate for supplying control signals to the array of pixels to selectively actuate the deformable members of the pixels, wherein each switch comprises an actuating member movable between an active state and an inactive state, whereby in the active state any control signal supplied to the switch passes through the switch, and in the inactive state any control signal supplied to the switch is prevented from passing through the switch. Fabrication methods are also disclosed.

Claims

1. A display device comprising:

a transparent substrate;

an array of pixels formed on the substrate, each pixel comprising a transparent electrode and a deformable member electrically actuated between a first state and a second state, wherein in the first state a liquid including a dye is disposed in a gap between the transparent electrode and the deformable member and wherein in the second state the defonnable member reduces the gap between the transparent electrode and the deformable member such that the liquid is substantially removed between the deformable layer and the transparent electrode; and

a plurality of switches formed on the substrate for supplying control signals to the array of pixels to selectively actuate the deformable members of the pixels, wherein each switch comprises an actuating member movable between an active state and an inactive state, whereby in the active state any control signal supplied to the switch passes through the switch, and in the inactive state any control signal supplied to the switch is prevented from passing through the switch.

2. The display device as recited in claim 1, wherein the deformable member includes a reflective surface which reduces the gap by displacing a portion of the liquid when the deformable member is in the second state.

3. The display device as recited in claim 2, wherein the dye is black such that light is reflected from the deformable member, when the deformable member is in the second state and light is absorbed in the gap when the deformable member is in the first state.

4. The display device as recited in claim 3, wherein the dye includes Sudan Black.

5. The display device as recited in claim 3, wherein the dye includes Naphthol Blue Black.

6. The display device as recited in claim 1, wherein the deformable member includes a light absorbent surface which contacts an insulation layer over the transparent electrode in the second state.

7. The display device as recited in claim 6, wherein the dye is white such that light is reflected from the gap when the deformable member is in the second state and light is absorbed on the deformable member when the deformable member is in the first state.

8. The display device as recited in claim 1, wherein the deformable member is bistable having a hysteresis such that only the first and second states are permitted.

9. The display device as recited in claim 1, wherein the switches include microelectromechanical switches.

10. The display device as recited in claim 1, wherein the deformable member is actuated on hinges integrally formed with the deformable member.

11. The display device as recited in claim 1, further comprising an active area including the liquid therein and a first seal region for maintaining the liquid in the active area.

12. The display device as recited in claim 11, further comprising a second seal region for maintaining an inert gas therein between the first seal region and the second seal region such that the plurality of switches exist in the inert gas.

13. The display device as recited in claim 11, wherein the transparent electrode forms a data line for controlling the pixels and the deformable member forms a gate line for controlling the pixels such that voltage differences provided by control signals between the gate line and the data line provide a force for actuating the deformable member;

and

the plurality of switches are formed on the substrate for supplying the control signals on gate lines and data lines to the array of pixels to selectively actuate the deformable members of the pixels.

14. The display device as recited in claim 13, further comprising a shift register for addressing the gate lines, the shift register including a portion of the plurality of switches and another portion of the plurality of switches for demultiplexing the data lines.

15. A display device comprising:

a substrate;

an array of pixels formed on the substrate, each pixel comprising an electrically actuated switch, a storage capacitor, a transparent substrate and a deformable member electrically actuated between a plurality of states, wherein in each of the states a liquid including a dye is disposed in a gap between a transparent substrate and the deformable member in an active area and wherein the gap is adjustable according to voltages applied to the deformable member and the storage capacitor to change an amount of liquid disposed between the transparent substrate and a deformable member thereby reflecting light from the active area according to different intensities.

16. The display device as recited in claim 15, wherein the deformable member includes a reflective surface for reflecting light through the transparent substrate and wherein the dye is black.

17. The display device as recited in claim 15, wherein the deformable member includes a light absorbent surface for absorbing light through the transparent substrate and wherein the dye is white.

18. The display device as recited in claim 15, wherein the deformable member is actuated on hinges integrally formed with the deformable member.

19. The display device as recited in claim 15, further comprising an active device area including the liquid therein and a first seal region for maintaining the liquid in the active area.

20. The display device as recited in claim 19, further comprising a second seal region for maintaining an inert gas therein between the first seal region and the second seal region such that the plurality of switches exist in the inert gas.

21. The display device as recited in claim 15, further comprising a shift register for addressing gate lines which are coupled to each pixel.

22. The display device as recited in claim 15, wherein the switches include microelectromechanical switches.