Microstructured segmented electrode film for electronic displays

• US 20020131151A1
• Filed: 03/14/2001
• Published: 09/19/2002
• Est. Priority Date: 03/14/2001
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Biernath, Rolf W., Engler, David A.
• Granted Patent: US 6,700,695 B2
• Time in Patent Office: Days
• US Class Current: 359/296
• CPC Class Codes: G02B 26/026 based on the rotation of particles under the influence of an external field, e.g. gyricons, twisting ball displays based on orientable dipolar particles G02F1/172; based on electrophoresis G02F1/167

Abstract

A segmented electrode film is used with a display panel, such as “gyricon” (or twisting particle) displays or other forms of electronic paper, such as particulate electrophoretic displays, which are available from E-Ink Corporation. The display panel has a viewing surface and a backside surface opposing the viewing surface. The electrode film can be on the viewing surface, in which case the electrode film must be transparent, or the backside surface or in a printer. The display panel comprises surrounding media containing particles which are responsive to changes in a magnetic field are optically anisotropic toward the viewing surface. The electrode film has an array layer and an electrode layer, where the array layer provides a support structure for the electrode layer. The array layer is electrically non conductive and in contact with the surface of the display panel. The array layer has a plurality of mesa shaped segments where each mesa shaped segment has a top face and side walls extending downward from the top face. The electrode layer formed of an electrically conductive material coats the array layer and is exposed for contact by an electrical stimulus, such as a stylus. The electrode layer is deposited by a sputtering process, wherein the electrode layer is thicker on the top face than on the side walls, producing resistive bridges between adjacent top faces. The resistive bridges partially electrically isolate each electrode from the other electrodes in the electrode layer.

Claims

1. An electronic display comprising:

a display panel having a viewing surface and a backside surface opposing the viewing surface, the display panel comprising;

particles which are optically anisotropic toward the viewing surface and responsive to changes in magnetic field; and

a surrounding media containing the particles;

an array layer in contact with the viewing surface of the display panel, the array layer being formed of an electrically non conductive material; and

an electrode layer coating the array layer, the electrode layer formed of an electrically conductive material, the electrode layer exposed for contact by an electrical stimulus, the electrode layer providing a plurality of electrodes, each electrode of the electrode layer being partially electrically isolated from the other electrodes in the electrode layer.

2. The electronic display of claim 1, wherein the array layer has a plurality of mesa shaped segments, each mesa shaped segment comprising:

a top face; and

side walls extending downward from the top face,

wherein each of the mesa shaped segments provide a support structure for one of the electrodes.

3. The electronic display of claim 2, wherein the electrode layer is thicker on the top face than on the side walls producing resistive bridges between adjacent top faces, the resistive bridges partially electrically isolating each electrode from the other electrodes in the electrode layer.

4. The electronic display of claim 3, wherein the electrode layer is ITO (Indium Tin Oxide).

5. The electronic display of claim 1, wherein the electronic display further comprising:

an electrode in contact with the backside surface of the display panel;

wherein the array layer provides an array of mesa shaped segments, wherein each mesa shaped segments provide a support structure for one of the electrodes, each mesa having a substantially flat top face and four side walls extending downward defining valleys relative to the top face, the sidewalls recess at included angles of 70 degrees or greater relative to the top faces; and

wherein the electrode layer has an electrode thickness over the mesa shaped segments of sufficient thickness and sufficient conductivity to form substantially conductive electrode plates, the electrode layer having a top face thickness and a valley thickness over the sidewalls, the sidewall thickness being thinner than the top thickness and of sufficient thinness and sufficient resistivity to form resistive bridges between adjacent electrode plates.

6. The electronic display of claim 1, further comprising a stylus electrically connected to address select electrodes of the electrode layer.

7. A electrode film comprising;

a sheet formed of a substantially electrically insulative material, the sheet having a textured surface, the textured surface providing a plurality of mesa structures each having an electrode face extending generally in the plane of the textured surface and peripheral side walls around the electrode face defining valleys relative to the electrode face; and

a conductive layer deposited over the textured surface of the sheet, the conductive layer having an electrode thickness over the electrode faces of the mesa structures of sufficient thickness and sufficient conductivity to form substantially conductive electrode plates, the conductive layer having a valley thickness over the peripheral side walls which is thinner than the electrode thickness and of sufficient thinness and sufficient resistivity to form resistive bridges between adjacent electrode plates.

8. The electrode film of claim 7, wherein the electrode film is disposed in a printer.

9. The electrode film of claim 7, wherein the sheet and conductive layer are substantially transparent or translucent to visible light.

10. The electrode film of claim 7, wherein the sidewalls recess at included angles of 70 degrees or greater relative to the electrode faces.

11. The electrode film of claim 7, wherein substantially all mesa structures are coated with the conductive layer by a sputtering process.

12. The electrode film of claim 11, wherein the conductive layer is ITO (Indium Tin Oxide).

13. The electrode film of claim 12, wherein the ITO conductive layer is up to about 4 nm thick.

15. The method of claim 14, wherein the mesa shaped segments have a substantially flat top face and side walls extending downward from the top face, wherein the sidewalls recess at included angles of 70 degrees or greater relative to the top faces, each mesa side wall intersects with an adjoining mesa side wall to form a valley relative to the top face.

16. The method of claim 15, wherein the depositing step is performed by a sputtering process resulting in the top face electrode layer to be thicker than the side wall electrode layer to thereby forming resistive bridges between adjacent top faces, the resistive bridges surrounding each top face to at least partially electrically isolate each top face from the other top faces in the array.

17. The method of claim 16, wherein the conductive coating is ITO (Indium Tin Oxide).

14. A method of making an electrode film substrate, the method comprising;

texturing a surface of a substrate into an array of mesa shaped segments having a repeatable mesa size and repeatable distance between each mesa shaped segment, the substrate being electrically non conductive; and

depositing a conductive coating on the surface of the substrate thereby forming an electrode layer with one electrode on each mesa shaped segment and resistive bridges surrounding each electrode to at least partially electrically isolate each electrode from the other electrodes in the electrode layer.