Display assembly having flexible transistors on a flexible substrate

• US 6,885,032 B2
• Filed: 11/20/2002
• Issued: 04/26/2005
• Est. Priority Date: 11/21/2001
• Status: Expired due to Term

• Current Assignee: Metrologic Instruments Incorporated (Honeywell International Inc.)
• Original Assignee: Visible Tech-Knowledgy, Inc.
• Inventors: Forbes, Charles, Turner, Christopher, Gelbman, Alexander, Wagner, Sigurd, Gleskova, Helena
• Primary Examiner(s): Abraham, Fetsum
• Application Number:
  US10/300,514
• Publication Number:
  US 20030134460A1
• Time in Patent Office: 888 Days
• Field of Search: 349/112, 349/113, 257/72, 257/59
• US Class Current: 257/72
• CPC Class Codes: G02F 1/133305 Flexible substrates, e.g. plastics, organic film
• CPC Class Codes: G02F 1/1334 based on polymer dispersed liquid crystals, e.g. microencapsulated liquid crystals
• CPC Class Codes: G02F 1/1368 in which the switching element is a three-electrode device G02F1/136277 takes precedence
• CPC Class Codes: H01L 27/1214 comprising a plurality of TFTs formed on a non-semiconducting substrate, e.g. driving circuits for AMLCDs
• CPC Class Codes: H01L 27/1218 with a particular composition or structure of the substrate
• CPC Class Codes: H01L 27/1262 with a particular formation, treatment or coating of the substrate
• CPC Class Codes: H01L 27/1288 employing particular masking sequences or specially adapted masks, e.g. half-tone mask
• CPC Class Codes: H01L 29/66765 Lateral single gate single channel transistors with inverted structure, i.e. the channel layer is formed after the gate
• CPC Class Codes: H01L 29/78603 characterised by the insulating substrate or support H01L29/78657 takes precedence
• CPC Class Codes: H01L 29/78669 with inverted-type structure, e.g. with bottom gate

Abstract

A thin film transistor array fabricated on a polyimide substrate forms a backplane for an electronic display. The thin film transistor array incorporates gate electrodes, a gate insulating layer, semiconducting channel layers deposited on top of the gate insulating layer, a source electrode, a drain electrode and a contact layer beneath each of the source and drain electrodes and in contact with at least the channel layer. An insulating encapsulation layer is positioned on the channel layer. The layers are deposited onto the polyimide substrate using PECVD and etched using photolithography to form the backplane.

Claims

1. A portable electronic device comprising,

a housing to house a portion of one or more components of said portable electronic device;

and

a display assembly coupled to a flexible backplane assembly for displaying content to a user of the portable electronic device, the flexible backplane assembly has formed thereon at least one transistor having at least one layer of amorphous silicon, wherein the flexible backplane assembly including the at least one transistor being capable of flexing in one or more dimensions to change a topography of a surface of the flexible backplane assembly, and wherein a portion of the display assembly forms a portion of the housing.

2. The portable electronic device of claim 1, wherein the display assembly comprises a flexible display medium having a plurality of pixels capable of displaying content to the user of the portable electronic device and capable of flexing to change a topography of a surface of the flexible display assembly.

3. The portable electronic device of claim 2, wherein the flexible display assembly comprises,

a flexible layer of transparent material disposed over a portion of the flexible display medium.

4. The portable electronic device of claim 3, wherein the flexible display medium comprises, a bi-stable, non-volatile display medium.

5. The portable electronic device of claim 4, wherein the flexible display medium comprises,

electrophoretic material having a pattern of addressable pixel locations;

and

an activation grid for supplying a charge to selected addressable pixel locations to form the content for displaying to the user.

6. The portable electronic device of claim 4, wherein the flexible display medium comprises at least one of a plurality of bichromal spheres, a plurality of pneumatic liquid crystals, a plurality of cholesteric liquid crystals, and a plurality of chiral compounds.

7. The portable electronic device of claim 3, wherein the flexible display medium comprises a volatile medium.

8. The portable electronic device of claim 7, wherein the volatile medium comprises at least one of, an organic light emitting diode, a liquid crystal, and a polymer dispersed liquid crystal.

9. The portable electronic device of claim 3, wherein the flexible display medium comprises a medium that includes at least one of a surface stabilized ferroelectric liquid crystal, a fast multi stable liquid crystal, and OYNX™

chemical substance.

10. The portable electronic device of claim 2, wherein the flexible display assembly is capable of having a first portion of the surface of the flexible display assembly flex to conform to a first radius and a second portion of the surface of the flexible display assembly flex to conform to a second radius.

11. The portable electronic device of claim 1, wherein the flexible backplane assembly comprises a matrix of transistors formed on a flexible polyimide substrate.

12. The portable electronic device of claim 1, wherein the housing comprises, a moveable member moveable from a first position to a second position to access a portion of the portable electronic device.

13. The portable electronic device of claim 1, wherein the portable electronic device comprises at least one of, a personal digital assistant (PDA), a cell phone, a timepiece, and a mobile electronic device associated with a network.

14. A flexible electronic display having a plurality of pixels, the flexible electronic display comprising,

a flexible display medium for displaying indicia to an operator, the flexible display medium having a first surface adjacent to a transparent reference electrode layer and a second surface adjacent to at least one thin film transistor having at least one layer of amorphous silicon, the indicia providing the operator with indications of a state of a monitored process;

and

wherein the at least one thin film transistor being formed on a substrate capable of flexing in a plurality of dimensions, the at least one thin film transistor, the transparent reference electrode layer, and the flexible display medium flex to adapt to one or more contours of a surface of an instrument panel at least during mounting of said flexible electronic display thereto.

15. The flexible electronic display of claim 14, further comprising a device coupled to the at least one thin film transistor, the device providing the at least one thin film transistor with an input for rendering on said flexible display medium, the input including at least a response from a stimulus.

16. The flexible electronic display of claim 15, further comprising one or more decoder circuits coupled between the at least one thin film transistor and said device, the one or more decoder circuits capable of selecting a plurality of transistors to address a selected pixel of said plurality of pixels of said flexible electronic display in response to said input from said device.

17. The flexible electronic display of claim 14, wherein the instrument panel is mounted in a mechanized vehicle.

18. The flexible electronic display of claim 16, wherein the mechanized vehicle includes at least one of an automobile, a locomotive, an airplane, a motorcycle, a watercraft, and a truck.

19. The flexible electronic display of claim 14, wherein the instrument panel is incorporated into a device for determining a present value of a quantity under observation.

20. The flexible electronic display of claim 14, wherein the plurality of pixel elements are capable of maintaining state in an absence of a selected input to said flexible display medium.

21. The flexible electronic display of claim 20, wherein the plurality of pixel elements are formed of a compound that includes at least one of, an electronic ink, an electrophoretic material, a plurality of bichromal spheres, a plurality of nematic liquid crystals, a plurality of cholesteric liquid crystals, and a plurality of chiral compounds.

22. The flexible electronic display of claim 21, wherein the electronic ink comprises a compound formed from a plurality of particles, each of the plurality of particles is capable of entering one of two states to form a bi-stable imaging medium, wherein a first of the two states orients a selected one of the plurality of particles to reflect light and a second of the two states orients the selected one of the plurality of particles to absorb light.

23. The flexible electronic display of claim 21, wherein the electronic ink comprises at least one of, a plurality of bichromal spheres, a plurality of nematic liquid crystals, a plurality of cholesteric liquid crystals, and a plurality of chiral compounds.

24. The flexible electronic display of claim 21, wherein the electrophoretic material comprises at least one of, a plurality of bichromal spheres, a plurality of nematic liquid crystals, a plurality of cholesteric liquid crystals, and a plurality of chiral compounds.

25. The flexible electronic display of claim 24, wherein the plurality of pixel elements are formed of a compound that includes at least one of, an organic light emitting diode, a liquid crystal, and a polymer dispersed liquid crystal.

26. The display device of claim 25, further comprising a transponder layer coupled to the matrix of transistors for performing radio frequency identification (RFID).

27. The display device of claim 25, wherein the matrix of transistors and the plurality of pixels form a portion of an electronic label employing electronic ink.

28. The flexible electronic display of claim 21, wherein the electronic ink comprises conductive ink having an arrangement of particles, each of the particles has disposed therein an electrophoretic composition of a fluid and a suspension of colloidal material, the conductive ink being printable on an a medium by an image reproducing system.

29. The flexible electronic display of claim 14, wherein the plurality of pixel elements cause the flexible display medium to change state when a selected input to said flexible display medium is interrupted.

30. The flexible electronic display of claim 14, wherein the plurality of pixel elements cause the flexible display medium to become randomly dispersed when a selected input to said flexible display medium is interrupted.

31. The flexible electronic display of claim 14, wherein the plurality of pixel elements cause the flexible display medium to power off when a selected input to said flexible display medium is interrupted.

32. The flexible electronic display of claim 14, wherein the flexible display medium comprises a plurality of pixel elements formed of a compound that includes at least one of, a surface stabilized ferroelectric liquid crystal, a fast multi stable liquid crystal, and an OYNX™

chemical compound.

33. A display device for displaying content to a user, said display device comprising,

a matrix of transistors formed on a flexible substrate, the flexible substrate capable of flexing in one or more dimensions with the transistors formed thereon to adapt to a desired contour, and

a plurality of pixels coupled to the matrix of transistors, each of the plurality of pixels being addressable by the matrix of transistors to transfer a charge from a selected one of the matrix of transistors to one of the plurality of pixels to display a portion of the content to the user.

34. The display device of claim 33, wherein the flexible substrate comprises a polyimide material.

35. The display device of claim 33, wherein the matrix of transistors comprises a plurality of thin film transistors having at least one layer of amorphous silicon.

36. The display device of claim 33, wherein each of the plurality of pixels is coupled to at least one capacitor, the capacitor holding the charge transferred to the selected pixel from the matrix of transistors.

37. The display device of claim 36, wherein the transistor that passes the charge to cause the selected pixel to change state is constructed on a polyimide material in a plurality of geometric patterns.

38. The display device of claim 37, wherein the plurality of geometric patterns comprises a plurality of two dimensional shapes.

39. The display device of claim 33, wherein the plurality of pixels are formed of a compound that includes at least one of an electronic ink with a plurality of bichromal spheres, a electrophoretic material with a plurality of microencapsulated bichromal spheres, a electrophoretic material with particles micro encapsulated in a suspension fluid of a contrasting color, a plurality of nematic liquid crystals, a plurality of cholesteric liquid crystals, and a plurality of chiral compounds.

40. The display device of claim 39, wherein each of the materials comprises a compound formed from a plurality of particles, each of the plurality of particles is capable of entering one of two states to form a bi-stable imaging medium, wherein a first of the two states orients a selected one of the plurality of particles to reflect light and a second of the two states orients the selected one of the plurality of particles to absorb light, to reflect light, or to absorb light of different frequencies thereby creating contrasting colors.

41. The display device of claim 39, wherein the electronic ink comprises conductive ink having an arrangement of particles, each of the particles has disposed therein an electrophoretic composition of a fluid and a suspension of colloidal material, the conductive ink being printable on an a medium by an image reproducing system.

42. The display device of claim 33, wherein the plurality of pixels change state when a selected input to said display device is interrupted.

43. The display device of claim 33, wherein the plurality of pixels are formed of material that includes at least one of an organic light emitting diode, a liquid crystal, and a polymer dispersed liquid crystal.

44. The display device of claim 33, wherein the plurality of pixels comprises a compound formed with at least one of, a surface stabilized ferroelectric liquid crystal, a fast multi stable liquid crystal, and an OYNX™

chemical compound.

45. The display device of claim 33, further comprising a transparent layer of conductive material disposed over a surface of each of the plurality of pixels to form an electrode for selecting one of the plurality of pixels.

46. The display device of claim 45, wherein a pointing device passes over a portion of the electrode to select at least one of the plurality of pixels corresponding to the selected portion of the electrode.

47. The display device of claim 33, wherein the display device displays content from a stored location, the stored location present in a portion of the display device.

48. The display device of claim 33, further comprising a processor coupled to the matrix of transistors, the processor producing and driving the matrix of transistors with a portion of the content said display device displays.

49. The display device of claim 33, wherein a portion of the content said display device displays is provided by an electronic device associated with a network.