PROCESS FOR FABRICATING A PANEL ARRAY OF ELECTROMECHANICAL LIGHT VALVES

• US 3,600,798 A
• Filed: 02/25/1969
• Issued: 08/24/1971
• Est. Priority Date: 02/25/1969
• Status: Expired due to Term

• Current Assignee: Ray H. Lee
• Original Assignee: Ray H. Lee
• Inventors: Lee, Ray H.
• Primary Examiner(s): Campbell, John F.
• Assistant Examiner(s): Heist, D. M.
• Application Number:
  US04/801,971
• Time in Patent Office: 910 Days
• Field of Search: 29/592 178/7.3
• US Class Current: 29/592.1
• CPC Class Codes: G09F 9/372 the positions of the elements being controlled by the application of an electric field
• CPC Class Codes: Y10T 29/49002 Electrical device making

Abstract

Electromechanical light valves in a panel array are fabricated by a process including several metal patterning steps. Each light valve consists of a housing having grounded conducting walls for shielding the interior thereof from external electrostatic forces produced by surrounding valves in the array or from other external electrostatic forces. These walls are formed in a series of processing steps on a light transparent substrate coated with a conductive coating. Light from a source enters one end of the housing through a light transparent substrate to which is mounted an electrostatically controlled leaf shutter for each valve also formed in a series of processing steps. Upon completion of the processing for forming the individual leaf shutters on the one transparent substrate and the valve housings on the other transparent substrate, the two transparent panels are aligned to form an array of electromechanical light valves. The display state of the individual light valves may be modulated by a video signal in a system that makes use of the capacitance of the individual valve as a storage device for transforming the video signal, which is available only during a writing time of short duration to a display signal. Necessary components for each of the light valves required in a display duration modulation system are fabricated in the process for producing the light valve array.

Claims

1. A process for the fabrication of an array of light valves comprising:

forming an array of shutter supports of a conductive opaque material on one side of a first transparent substrate, covering the first substrate with a separating material in areas defining the configuration of the light valve array, depositing a shutter plate for each light valve in the array with one edge thereof supported by a shutter support over the separated material, forming an array of valve walls of a conductive opaque material on a conductIve coating covering a second transparent substrate, removing the separating material from the first substrate to form an array of cantelevered shutter plates, and aligning the supports on the first substrate with the valve walls on the second substrate and joining the two substrates to form an array of light valves.

2. A process for fabricating an array of light valves as set forth in claim 1, wherein the step of depositing the shutter plates includes evaporating a metal over a supporting material covering the first substrate, and plating the evaporated metal to the desired thickness.

3. A process for fabricating an array of light valves as set forth in claim 2, wherein the step of forming the array of valve walls includes selectively etching a metal film laminated to the conductive coating covering the second transparent substrate.

4. A process for fabricating a column and row array of light valves comprising:

producing an array of support bars in columns of a conductive opaque material on the rough side of an optically ground glass substrate, covering the glass substrate with a separating material in areas defining the row and column configuration of the light valve array, depositing a metallic shutter plate for each light valve in the array with one edge thereof supported by a support bar over the separating material, forming an array of valve walls in a row configuration of a conductive opaque material on a conductive coating covering a second glass substrate, removing the separating material from the first glass substrate to form a cantilever shutter plate, and aligning the supports on the first glass substrate with the valve walls on the second substrate and joining the two substrates to form an array of light valves in a row and column.

5. A process for fabricating a column and row array of light valves as set forth in claim 4, including the step of forming isolation elements for isolating one valve from others in the array on each support bar intermediate the step of producing the support bars and covering the glass substrate with a separating material.

6. A process for fabricating a column and row array of light valves as set forth in claim 5, including the step of depositing a resistor between the supported edge of the shutter plate and the valve walls intermediate the steps of forming the array of valve walls and removing the separating material.

7. A process for fabricating a column and row array of light valves as set forth in claim 6, including the step of producing color filters of the three basic colors in a pattern over the entire light valve array after the step of forming the array of valve walls.

8. A process for fabricating a column and row array of light valves as set forth in claim 7 wherein the step of producing the array of support bars includes evaporating a metal over the rough side of the optically ground glass substrate, and selectively etching the metal to form an array of columns.

9. A process for fabricating a column and row array of light valves as set forth in claim 8 wherein the step of depositing the shutter plates includes evaporating a metal over the separating material, and plating the evaporated metal to the desired thickness.

10. A process for fabricating a column and row array of light valves as set forth in claim 9, wherein the step of forming the array of valve walls includes selectively etching a metal film laminated to the conductive coating covering the second glass substrate.

11. A process for fabricating a column and row array of light valves comprising:

evaporating a metal to the rough side of an optically ground glass substrate, selectively etching the evaporated metal to form conductive column bars on said glass substrate, forming an isolation element for isolating one light valve from the others in the array on each conductive column bar, evaporating a separating material in the space next to the formed isolated element on each column in the area to be covered by a shutter plate, evaporating shutter plates extending over the isolating elements and the separating material, plating the shutter plates to a desired thickness to form a metallic shutter plate for each light valve in the array with one edge thereof supported by a column bar, forming resistors on the shutter plates in the area of the supported edge, differentially etching the separating material from the first glass substrate to form a cantilever light valve shutter, patterning a metal film laminated over a conductive coating covering a second glass substrate in a configuration to outline sidewalls for each light valve in the array, selectively etching the metal film laminate from the second glass substrate to form an array of valve walls, differentially etching the laminated film and the conductive coating to the glass substrate in a pattern of parallel lines perpendicular to the column bars to separate the light valves into rows, and aligning the column pattern and shutter plates on the first substrate with the valve walls on the second substrate and joining the two substrates to form an array of light valves in a row and column configuration.

12. A process for fabricating a column and row array of light valves as set forth in claim 11 including:

coating the conductive coating of the second substrate with a negative resist colorized with one of the three primary display colors, exposing and developing the negative resist to obtain one of the desired color filters, and repeating the above two steps for the other two primary colors to obtain colored filters of the three primary colors in a pattern over the light valve array.