Display apparatus and methods for manufacture thereof

• US 20070002156A1
• Filed: 02/23/2006
• Published: 01/04/2007
• Est. Priority Date: 02/23/2005
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Pixtronix, Incorporated (Qualcomm, Inc.)
• Inventors: Barton, Roger, Payne, Richard, Gandhi, Jignesh, Fijol, John, Steyn, Jasper, Hagood, Nesbitt, Brosnihan, Timothy
• Granted Patent: US 7,405,852 B2
• Time in Patent Office: Days
• US Class Current: 348/296
• CPC Class Codes: G02B 26/04 by periodically varying the intensity of light, e.g. using choppers shutters, diaphragms for cameras G03B9/00; devices for eliminating or reducing the effect of flicker in projection systems G03B21/40
• CPC Class Codes: G02F 2203/12 spatial light modulator
• 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 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2310/0262 The addressing of the pixel, in a display other than an active matrix LCD, involving the control of two or more scan electrodes or two or more data electrodes, e.g. pixel voltage dependent on signals of two data electrodes
• 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

Display devices incorporating shutter-based light modulators are disclosed along with methods of manufacturing such devices. The methods are compatible with thin-film manufacturing processes known in the art and result in displays having lower power-consumption.

Claims

1. A method of forming a spatial light modulator including a shutter supported by a compliant beam, the method comprising:

forming a mold on a substrate, wherein the mold includes a lower horizontal surface, an upper horizontal surface and a wall;

depositing a beam material on the lower horizontal surface and the wall of the mold;

removing the beam material deposited on the lower horizontal surface of the mold while leaving the majority of the beam material deposited on the wall of the mold in place to form the compliant beam;

forming the shutter coupled to the compliant beam; and

removing the mold, thereby releasing the shutter and remaining beam material.

2. The method of claim 1, wherein the lower horizontal surface of the mold comprises a top of a first sacrificial layer.

3. The method of claim 2, wherein removing the mold comprises removing the first sacrificial layer.

4. The method of claim 2, wherein the mold wall comprises a second sacrificial layer.

5. The method of claim 2, wherein removing the mold comprises removing the second sacrificial layer.

6. The method of claim 1, wherein removing the beam material comprises applying an anisotropic etch to the beam material.

7. The method of claim 6, comprising applying an electric potential to the substrate to control the direction of the anisotropic etch.

8. The method of claim 1, wherein the depositing of the beam material connects the beam material to an anchor disposed on the substrate.

9. The method of claim 1, wherein the depositing of the beam material connects the beam material to an anchor deposited on a layer of material deposited beneath the lower horizontal surface of the mold.

10. The method of claim 9, wherein the depositing of the beam material establishes an electrical connection between the beam material and the anchor.

11. The method of claim 1, wherein forming the shutter comprises depositing a shutter layer on the upper horizontal surface of the mold such that the shutter layer is connected to the beam material.

12. The method of claim 11, wherein the shutter layer comprises amorphous silicon.

13. The method of claim 11, wherein the shutter layer is formed from a material other than the beam material.

14. The method of claim 11, wherein the shutter layer is formed from the same material as the beam material.

15. The method of claim 14, wherein the beam material and the shutter layer together comprise a composite of a plurality of layers.

16. The method of claim 15 wherein the composite comprises at least 1 layer of amorphous silicon and at least one layer of a metal.

17. The method of claim 15 wherein the plurality of layers yields an unbalanced level of stress in the compliant beams.

18. The method of claim 1, wherein the mold wall is substantially normal to the substrate.

19. The method of claim 1, wherein the beam material is deposited on the wall of the mold to have a thickness of less than 2 about microns.

20. The method of claim 1, wherein the beam material is deposited on the wall of the mold to have a thickness of less than about 1.5 microns.

21. The method of claim 1, wherein the beam material is deposited on the wall of the mold to have a thickness of less than about 1.0 microns.

22. A spatial light modulator comprising:

a substrate defining a plane;

a shutter suspended over the substrate by a compliant beam, wherein the cross sectional thickness of the compliant beam in a dimension parallel to the plane of the substrate is less than about 2 microns.

23. The spatial light modulator of claim 22, wherein the dimension of the compliant beam is less than about 1.5 microns.

24. The spatial light modulator of claim 22, wherein the dimension of the compliant beam is less than about 1 micron.

25. A method of manufacturing a display device comprising:

depositing a layer of a dielectric material directly on a substantially transparent substrate;

depositing a layer of metal directly on top of the dielectric material;

forming a plurality of apertures in the layer of metal;

forming a control matrix on top of the metal layer; and

forming a plurality of light-modulating shutter assemblies on top of and in electrical communication with the control matrix such that the control matrix controls the light modulation functionality of the plurality of shutter assemblies.

26. The method of claim 25, wherein the control matrix includes a plurality of thin film components.

27. The method of claim 26, wherein the thin-film components comprise switches.

28. A method of manufacturing a display device comprising:

depositing a first layer of a dielectric material directly on a substantially transparent substrate;

depositing a second layer of a dielectric material directly on top of the first dielectric material depositing a layer of metal directly on top of the dielectric material;

forming a plurality of apertures in the layer of metal;

forming a control matrix on top of the metal layer; and

forming a plurality of light-modulating shutter assemblies on top of and in electrical communication with the control matrix such that the control matrix controls the light modulation functionality of the plurality of shutter assemblies.

29. A method of claim 28 wherein the second dielectric material has a refractive index lower than that of the first dielectric material.

30. A method of manufacturing a display device comprising:

depositing a high-reflectance layer on a substantially transparent glass substrate;

forming a plurality of apertures in the high-reflectance layer;

depositing an insulating layer directly on top of the high-reflectance layer;

depositing a plurality of thin-film components on the insulating layer;

forming a plurality of light-modulating shutter assemblies above, and in electrical communication with, the plurality of thin film components such that the thin-film components form a control matrix for controlling the light modulation of the plurality of light-modulating shutter assemblies.

31. The method of claim 30, wherein the high-reflectance layer has a reflectance of greater than 90%.

32. The method of claim 30, wherein the high-reflectance layer comprises a composite layer of at least one metal and at least one dielectric.

33. The method of claim 30, wherein the high-reflectance layer comprises a densely deposited metal.

34. The method of claim 33, comprising depositing the metal of the high-reflectance layer using a sputter process.

35. The method of claim 33, comprising depositing the metal of the high-reflectance layer using an ion-assisted evaporation.

36. The method of claim 30, comprising forming a plurality of via holes in the insulating layer prior to the deposition of the plurality of thin-film components.

37. The method of claim 36, wherein depositing the thin-film components on the insulating layer forms electrical connections between the high-reflectance layer and the thin-film components at the via-holes.

38. A method of manufacturing a display device comprising:

depositing an aperture layer on a substantially transparent glass substrate;

forming a plurality of apertures in the aperture layer;

depositing an insulating layer directly on top of the aperture layer;

forming a plurality of via holes in the insulating layer;

forming a plurality of thin-film components on the insulating layer such that the plurality of thin-film components electrically connect to the aperture layer at the plurality of via holes; and

forming a plurality of light-modulating shutter assemblies above, and in electrical communication with, the plurality of thin film components such that the thin-film components form a control matrix for controlling the light modulation of the plurality of light-modulating shutter assemblies.

39. The method of claim 38, wherein the aperture layer comprises a light-blocking material.

40. The method of claim 38, wherein the aperture layer comprises a light-reflecting material.

41. The method of claim 38, wherein the aperture layer comprises a light-absorbing material.

42. The method of claim 38, wherein the aperture layer comprises a light-absorbing material and a light-reflecting material.

43. A method of manufacturing a display device comprising:

forming a plurality of thin-film components; and

forming a plurality of light modulating shutter assemblies on top of the thin-film components, wherein the plurality of shutter assemblies include a layer of amorphous silicon etched to form movable shutters.