Field emission array (FEA) addressed deformable light valve modulator

• US 6,346,776 B1
• Filed: 07/10/2000
• Issued: 02/12/2002
• Est. Priority Date: 07/10/2000
• Status: Expired due to Fees

• Current Assignee: Memsolutions, Inc.
• Original Assignee: Memsolutions, Inc.
• Inventors: Boysel, Robert Mark, Robinson, William P.
• Primary Examiner(s): Wong, Don
• Assistant Examiner(s): Vu, Jimmy T.
• Application Number:
  US09/612,909
• Time in Patent Office: 582 Days
• Field of Search: 315/169.1, 315/169.2, 315/169.3, 315/169.4, 313/310-311
• US Class Current: 315/169.3
• CPC Class Codes: G02B 26/0825 the reflecting element being a flexible sheet or membrane, e.g. for varying the focus flexible mirrors for cosmetic use A45D42/24
• CPC Class Codes: G09G 3/22 using controlled light sources
• 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

Abstract

A compact, high resolution, bright and long life modulator for projection displays, mates a field emission array (FEA) with a deformable light valve modulator (DLVM) of reflective operation in a thin vacuum package. The DLVM includes a continuous film mirror layer formed on or between one or more deformable layers on a transparent substrate. The field emitters (at least one per pixel) are driven to deliver primary electrons that strike and deposit a charge that produces electrostatic forces that locally deform the continuous film mirror layer. Because the mirror layer is a continuous film, i.e. not pixelated, the modulator resolution is limited only by the addressing resolution of the FEA. Mating the FEA and DLVM technologies also reduces the drive voltage requirements associated with typical FEA driven phosphor displays and scanned beam DLVMs thus improving their performance and extending the lifetime of each.

Claims

1. A light modulator, comprising:

a thin vacuum cell having a transparent faceplate;

a target in said vacuum cell adjacent said faceplate, said target comprising a continuous film mirror layer formed on or between one or more deformable layers;

a field emitter array (FEA) in said vacuum cell that comprises an array of field emitter tips that emit primary electrons that strike the backside of the target causing secondary electrons to be ejected; and

a collector grid in said vacuum cell that collects the ejected secondary electrons leaving a charge pattern on the backside of the target that produces electrostatic forces that deform said continuous film mirror layer.

2. The light modulator of claim 1, wherein said charge pattern comprises a number of scan lines, said FEA being patterned into a number of rows equal to the number of scan lines.

3. The light modulator of claim 2, wherein said field emitter tips are locally modulated to sweep the primary electrons back-and-forth along the respective scan lines.

4. The light modulator of claim 3, further comprising a segmented control grid that sweeps the primary electrons back-and-forth.

5. The light modulator of claim 1, wherein said charge pattern comprises a number of scan lines, said FEA being patterned into a number of rows less than the number of scan lines, said field emitter tips in each said row being locally modulated so that the emitted primary electrons sweep a plurality of scan lines.

6. The light modulator of claim 5, further comprising a segmented control grid that sweeps the primary electrons in each said row back-and-forth parallel to and orthogonal to the scan lines.

7. The light modulator of claim 1, wherein said charge pattern comprises a number of scan lines, said FEA being patterned into a number of rows equal the number of scan lines, said field emitter tips in each said row being locally modulated so that the emitted primary electrons sweep a first primary color along the scan lines, a second primary color orthogonal to and above the scan lines at a known period, and a third primary color orthogonal to and below the scan lines at a different period.

8. The light modulator of claim 6, further comprising a segmented control grid that sweeps the primary electrons in each said row back-and-forth parallel to and orthogonal to the scan lines.

9. The light modulator of claim 1, wherein said FEA is patterned into a number of rows of field emitters that address the target'"'"'s continuous film mirror layer, the resolution of said light modulator being limited by the resolution of the patterned FEA.

10. The light modulator of claim 9, wherein said field emitters are locally modulated to effectively increase the resolution of the patterned FEA.

11. The light modulator of claim 1, wherein the field emitter tips have a characteristic work function that defines their output of primary electrons for a given drive voltage, said deformable layers comprising materials that when outgassed in the vacuum cell increase the work function thereby enhancing the performance and extending the life of the emitter tips.

12. The light modulator of claim 11, wherein said deformable materials outgas methane.

13. The light modulator of claim 1, wherein said target comprises said continuous film mirror layer sandwiched between a first transparent deformable layer and a second insulating dielectric deformable layer and a third dielectric insulating layer on said second layer, at least one of the layers between the second layer and the transparent faceplate being electrically conductive so that when the third dielectric layer receives the charge pattern the continuous film mirror layer is locally deformed by electrostatic forces occurring between the charge pattern and the conductive layer.

14. The light modulator of claim 13, wherein said target does not comprise an X-ray absorption layer.