Micromolded integrated ceramic light reflector

• US 5,793,519 A
• Filed: 11/15/1996
• Issued: 08/11/1998
• Est. Priority Date: 11/15/1996
• Status: Expired due to Fees

• Current Assignee: Eastman Kodak Company
• Original Assignee: Eastman Kodak Company
• Inventors: Furlani, Edward P., Grande, William J., Ghosh, Syamal K.
• Primary Examiner(s): Ben, Loha
• Application Number:
  US08/749,715
• Time in Patent Office: 634 Days
• Field of Search: 359/290, 359/291, 359/292, 359/295, 359/254, 359/262, 359/224, 359/226, 359/230, 359/846, 257/434, 257/432, 264/657
• US Class Current: 359/291
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means

Abstract

A micromolded integrated ceramic light reflector which can be totally integrated with drive and control electronics embedded on the same substrate for use with image projection systems. Each light reflector can be molded to a size on the order of less than one (1) mm³ using the method of the present invention. Each light reflector includes a ceramic base element with a cavity and one surface thereof. A beam extends from one end of the cavity and cantilevers out therefrom above the cavity. The beam is made from the same ceramic as the base element and is coated with an electrically conductive ceramic coating which is also a good reflector of the visible radiation spectrum. The base of the cavity is coated with the same electrically conductive ceramic, or with a metallic coating. In either case, the coating is electrically grounded. When the beam is in its normal, undeflected position, light incident on the top surface of the beam reflects at a first angle. When a potential is applied to the activation electrode, the beam is deflected downward into the cavity. In this position, light incident on the beam reflects at a second angle. Thus, control of the light output to a given surface over a small spot (pixel) is achieved by controlling the potential across the ceramic light reflector.

Claims

1. A ceramic light reflector device comprising:

(a) a ceramic micromolded base element including a cavity formed in a surface thereof, said cavity including a bottom face;

(b) a ceramic beam integrally connected to said ceramic base element and cantilevered over said cavity;

(c) a first ceramic laminate on a top surface of said beam, said first ceramic laminate being electrically conductive; and

(d) an electrically conductive second laminate on said bottom face.

2. A light reflector device as recited in claim 1 further comprising:

(a) a drive and control electronics package affixed to said base element; and

(b) electrical conductor means connecting said drive and control electronics package to said first laminate on said top surface of said beam.

3. A reflector device as recited in claim 1 further comprising:

means for grounding said electrically conductive second laminate on said bottom face.

4. A light reflector device as recited in claim 1 wherein:

said micromolded base element and said beam are molded using fine particles of zirconia alloyed with at least one secondary oxide powder.

5. A light reflector device as recited in claim 4 wherein:

said at least one secondary oxide powder is selected from the group consisting of yttria, ceria, calcia and magnesia.

6. A ceramic light reflector device as recited in claim 4 wherein:

said micromolded base element and said beam are molded using fine particles of zirconia alloyed with yttria present in the range of from about 0.5 to 5.0 mole percent to yield tetragonal zirconia.

7. A ceramic light reflector device as recited in claim 4 wherein:

said micromolded base element and said beam are molded using fine particles of zirconia alloyed with calcia present in the range of from about 0.5 to 5.0 mole percent to yield tetragonal zirconia.

8. A ceramic light reflector device as recited in claim 4 wherein:

said micromolded base element and said beam are molded using fine particles of zirconia alloyed with magnesia present in the range of from about 0.1 to 1.0 mole percent to yield tetragonal zirconia.

9. A ceramic light reflector device as recited in claim 1 wherein:

said first laminate on said top surface of said beam is integral with said beam.

10. A ceramic light reflector device as recited in claim 9 wherein:

said electrically conductive second laminate on said bottom face is integral with said micromolded base element.

11. A ceramic light reflector device as recited in claim 10 wherein:

said electrically conductive second laminate is selected from a group consisting of ceramic carbides, ceramic borides, and ceramic silicides.

12. A ceramic light reflector device as recited in claim 9 wherein:

said first laminate is titanium nitride.

13. A light reflector device as recited in claim 1 wherein:

said first ceramic laminate is reflective of visible light.

14. A light reflector device as recited in claim 1 wherein:

said ceramic micromolded base element and said ceramic beam have a tetragonal zirconia polycrystal structure.

15. A light reflector device as recited in claim 1 wherein:

said first ceramic laminate is integrally connected to said ceramic beam.

16. A method for micromolding a ceramic light reflector comprising the steps of:

(a) etching a silicon wafer to generate a master mold;

(b) forming a negative master from a micro feature replicating material using said master mold;

(c) mounting the negative master in a die;

(d) placing a ceramic powder in the die;

(e) compression molding the ceramic powder to form a green base element with a cavity in one surface thereof;

(f) forming a green beam from the ceramic powder;

(g) supporting the green beam on the green base element such that the green beam is cantilevered over the cavity; and

(h) sintering the green beam and the green base element.

17. An electrostatic light reflector device comprising:

(a) a micromolded ceramic base element including a cavity formed in a surface thereof, said cavity including a bottom face;

(b) a ceramic beam sintered to said base element and cantilevered over said cavity;

(c) a first ceramic laminate sintered to a top surface of said beam, said first ceramic laminate being reflective of visible light and also being electrically conductive; and

(d) an electrically conductive second laminate sintered on said bottom face.

18. An electrostatic light reflector device as recited in claim 17 further comprising:

(a) a drive and control electronics package affixed to said base element; and

(b) electrical conductor means connecting said drive and control electronics package to said first ceramic laminate on said top surface of said beam.

19. An electrostatic light reflector device as recited in claim 17 further comprising:

means for grounding said electrically conductive second laminate on said bottom face.

20. An electrostatic light reflector device as recited in claim 17 wherein:

said ceramic micromolded base element and said ceramic beam are molded using fine particles of zirconia alloyed with at least one secondary oxide powder.

21. An electrostatic light reflector device as recited in claim 20 wherein:

said at least one secondary oxide powder is selected from the group consisting of yttria, ceria, calcia and magnesia.

22. A method for micromolding a ceramic light reflector comprising the steps of:

(a) etching a silicon wafer to generate a master mold;

(b) forming a negative master from a micro feature replicating material using said master mold;

(c) mounting the negative master in a die;

(d) placing a ceramic powder in the die;

(e) compression molding the ceramic powder to form a green base element with a cavity in one surface thereof;

(f) forming a green beam from the ceramic powder;

(g) forming a first green ribbon from an electrically conductive ceramic which reflects light in the visible spectrum;

(h) forming a second green ribbon from an electrically conductive ceramic;

(i) supporting the green beam and the first green ribbon on the green base element such that the green beam and the first green ribbon are cantilevered over the cavity; and

(j) sintering the green beam, the first green ribbon and the green base element.

23. A method as recited in claim 22 further comprising the step of:

placing the second green ribbon on a bottom surface of the cavity prior to said sintering step.

24. A method as recited in claim 22 wherein:

the ceramic powder is zirconia alloyed with at least one secondary oxide powder selected from the group consisting of yttria, ceria, calcia and magnesia.

25. A method as recited in claim 24 wherein:

the green beam and green base element have a tetragonal zirconia polycrystal structure after said sintering step.

26. A method as recited in claim 22 wherein:

said forming steps for forming the first and second green ribbons are performed by tape casting.

27. A method as recited in claim 22 wherein:

the ceramic powder used in said compression molding step and said step of forming the green beam is zirconia alloyed with magnesia present in the range of from about 0.1 to 1.0 mole percent to yield tetragonal zirconia.

28. A method as recited in claim 22 wherein:

the ceramic powder used in said compression molding step and said step of forming the green beam is zirconia alloyed with yttria present in the range of from about 0.5 to 5.0 mole percent to yield tetragonal zirconia.

29. A method as recited in claim 22 wherein:

the ceramic powder used in said compression molding step and said step of forming the green beam is zirconia alloyed with calcia present in the range of from about 0.5 to 5.0 mole percent to yield tetragonal zirconia.

30. A light reflector device comprising:

(a) a micromolded ceramic base element including a cavity formed in a surface thereof, said cavity including a bottom face;

(b) a ceramic beam sintered to said base element and cantilevered over said cavity;

(c) a first ceramic laminate sintered to a top surface of said beam, said first laminate being electrically conductive;

(d) an electrically conductive second ceramic laminate sintered on said bottom face.

31. A light reflector device as recited in claim 30 further comprising:

a coating on said first laminate, said coating having high reflectivity of light in the visible spectrum.

32. A light reflector device as recited in claim 30 wherein:

said first ceramic laminate is reflective of visible light.