Integrated electro-optic package for reflective spatial light

• US 5,539,554 A
• Filed: 12/21/1994
• Issued: 07/23/1996
• Est. Priority Date: 12/21/1994
• Status: Expired due to Fees

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Lebby, Michael S., Kelly, George R., Jachimowicz, Karen E.
• Primary Examiner(s): Moskowitz, Nelson
• Application Number:
  US08/360,509
• Time in Patent Office: 580 Days
• Field of Search: 359/62, 359/63, 359/69, 359/70, 359/83, 359/246, 359/247, 359/263, 359/253
• US Class Current: 349/58
• CPC Class Codes: G02F 1/133308 Support structures for LCD panels, e.g. frames or bezels
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G02F 1/133608 including particular frames or supporting means
• CPC Class Codes: G02F 1/133616 Front illuminating devices
• CPC Class Codes: G02F 2203/02 reflective

Abstract

An array of reflective LCSLM pixels formed on a substrate with a light polarizing layer positioned in overlying relationship to the array. A mounting support includes a waveguide portion having a light input, a light output, and a mirrored surface directing light from the input toward the output, the polarizing layer and the array are mounted on the input. A light source is mounted in the mirrored surface to direct light through the polarizing layer and evenly illuminate the array. Light reflected from the array is directed through the polarizing layer and onto the mirrored surface. A diffuser at the output forms an image plane for the reflected light. Electrical connections are made from the array, through leads in the support and to external contacts.

Claims

1. An integrated electro-optic package for reflective spatial light modulators comprising:

an array of reflective spatial light modulator pixels formed on a substrate with each pixel including a control circuit formed in the substrate, each control circuit including control terminals adjacent an outer edge of the substrate, a mirror positioned on the substrate in overlying relationship to the control circuit, and spatial light modulator material positioned in overlying relationship to the mirror so that light passing through the spatial light modulator material is reflected back through the spatial light modulator material;

a light polarizing layer positioned in overlying relationship to the array of reflective spatial light modulator pixels;

a mounting support including an electrical portion and an optical waveguide portion, with the optical waveguide portion having a light input surface, a light output surface, and a mirrored surface for directing light from the light input surface toward the light output surface, the polarizing layer and the array of reflective spatial light modulator pixels being mounted on the light input surface of the mounting support;

a light source mounted in the mirrored surface of the optical waveguide portion and positioned to direct light through the polarizing layer and onto the array of reflective spatial light modulator pixels with the light source spaced from the array of reflective spatial light modulator pixels, so that light from the light source substantially evenly illuminates the array of reflective spatial light modulator pixels, the array of reflective spatial light modulator pixels being positioned so that reflected light from the array of reflective spatial light modulator pixels is directed through the polarizing layer, into the light input surface and onto the mirrored surface through the optical portion; and

a diffuser mounted in overlying relationship to the light output surface of the optical waveguide portion of the mounting support to form an image plane for reflected light from the array of reflective spatial light modulator pixels.

2. An integrated electro-optic package for reflective spatial light modulators as claimed in claim 1 wherein at least the optical waveguide portion of the mounting support is optically clear plastic.

3. An integrated electro-optic package for reflective spatial light modulators as claimed in claim 2 wherein the optically clear plastic has a temperature coefficient of expansion that is substantially similar to the array of reflective spatial light modulator pixels'"'"' temperature coefficient of expansion.

4. An integrated electro-optic package for reflective spatial light modulators as claimed in claim 1 wherein at least the optical waveguide portion of the mounting support is molded optically clear plastic.

5. An integrated electro-optic package for reflective spatial light modulators as claimed in claim 1 wherein the light source includes a light emitting diode.

6. An integrated electro-optic package for reflective spatial light modulators as claimed in claim 5 wherein the light source includes at least two light emitting diodes, each of which emit a different color of light.

7. An integrated electro-optic package for reflective spatial light modulators as claimed in claim 1 wherein the optical waveguide portion of the mounting support includes a molded optically clear plastic and the light source is a plurality of light emitting diodes embedded in the optically clear plastic.

8. An integrated electro-optic package for reflective spatial light modulators as claimed in claim 1 where, in the array of reflective spatial light modulator pixels, the layer of spatial light modulator material is a continuous layer across the entire array and each control circuit for each pixel formed in the substrate includes one contact, the array further including an optically clear contact positioned on an opposite side of the continuous layer with the one contact and the optically clear contact defining a pixel within the continuous layer.

9. An integrated electro-optic package for reflective spatial light modulators as claimed in claim 8 wherein the spatial light modulator material includes liquid crystal material.

10. An integrated electro-optic package for reflective spatial light modulators as claimed in claim 8 wherein the liquid crystal material includes ferroelectric light crystal material.

11. An integrated electro-optic package for reflective spatial light modulators as claimed in claim 8 wherein the optically clear contact for each pixel is formed in a layer if indium-tin-oxide deposited in overlying relationship to the continuous layer of spatial light modulator material.

12. An integrated electro-optic package for reflective spatial light modulators as claimed in claim 8 wherein the mirror positioned on the substrate is a polished pad of metal, one for each pixel, which pad of metal also forms the one contact included in the control circuit.

13. An integrated electro-optic package for reflective spatial light modulators as claimed in claim 10 wherein the polished pad of metal for each pixel is a polished pad of aluminum.

14. An integrated electro-optic package for reflective spatial light modulators as claimed in claim 1 wherein the electrical portion of the mounting support includes leads formed in the electrical portion so as to be in electrical contact with the control terminals adjacent an outer edge of the substrate of each control circuit and the leads further extend to an external portion of the housing to form external contacts for the control circuits.

15. An integrated electro-optic package for reflective spatial light modulators as claimed in claim 14 wherein the electrical portion of the mounting support is molded and the leads are a leadframe molded into the electrical portion of the mounting support.

16. An integrated electro-optic package for reflective liquid crystal spatial light modulators comprising:

a reflective liquid crystal spatial light modulator stack including a substrate with a plurality of control circuits formed therein, each control circuit including control terminals adjacent an outer edge of the substrate and an electrical contact mirror positioned on the substrate, each electrical contact mirror defining a pixel and a first electrical contact for the pixel, a layer of liquid crystal spatial light modulator material positioned in overlying relationship to the electrical contact mirrors so that light passing through the liquid crystal spatial light modulator material is reflected back through the liquid crystal spatial light modulator material, and an electrically conductive optically transparent layer of material positioned on an opposite surface of the liquid crystal spatial light modulator material to form a second electrical contact for each pixel;

a light polarizing layer positioned in overlying relationship to the reflective liquid crystal spatial light modulator stack;

a mounting support including an electrical portion and an optical waveguide portion, with the optical waveguide portion having a light input surface, a light output surface, and a mirrored surface for directing light from the light input surface toward the light output surface, the polarizing layer and the reflective liquid crystal spatial light modulator stack being mounted on the light input surface of the mounting support;

a light source mounted in the mirrored surface of the optical waveguide portion and positioned to direct light through the polarizing layer and onto the reflective liquid crystal spatial light modulator stack with the light source spaced from the reflective liquid crystal spatial light modulator stack, so that light from the light source substantially evenly illuminates the reflective liquid crystal spatial light modulator stack, the array of reflective liquid crystal spatial light modulator stack being positioned so that reflected light from the reflective liquid crystal spatial light modulator stack is directed through the polarizing layer, into the light input surface and onto the mirrored surface through the optical portion; and

a diffuser mounted in overlying relationship to the light output surface of the optical waveguide portion of the mounting support to form an image plane for reflected light from the reflective liquid crystal spatial light modulator stack.

17. An integrated electro-optic package for reflective liquid crystal spatial light modulators as claimed in claim 16 wherein the layer of liquid crystal spatial light modulator material is contained within a closed cavity having internal opposed flat surfaces, the electrical contact mirrors are affixed to one of the internal surfaces and the electrically conductive optically transparent layer is affixed to the other of the internal surfaces.

18. An integrated electro-optic package for reflective liquid crystal spatial light modulators as claimed in claim 17 wherein the closed cavity is defined by a surface of the substrate, a spacer affixed to the surface of the substrate and a glass plate affixed over the spacer.

19. An integrated electro-optic package for reflective liquid crystal spatial light modulators comprising:

a reflective liquid crystal spatial light modulator stack including

a substrate with a plurality of control circuits formed therein, each control circuit including control terminals adjacent an outer edge of the substrate and an electrical contact mirror positioned on the substrate, each electrical contact mirror defining a pixel and a first electrical contact for the pixel,

a layer of liquid crystal spatial light modulator material positioned in overlying relationship to the electrical contact mirrors so that light passing through the liquid crystal spatial light modulator material is reflected back through the liquid crystal spatial light modulator material,

an electrically conductive optically transparent layer of material positioned on an opposite surface of the liquid crystal spatial light modulator material to form a second electrical contact for each pixel, and

the layer of liquid crystal spatial light modulator material being contained within a closed cavity having internal opposed flat surfaces and defined by a surface of the substrate, a spacer affixed to the surface of the substrate and a glass plate affixed over the spacer with the electrical contact mirrors affixed to one of the internal surfaces and the electrically conductive optically transparent layer affixed to the other of the internal surfaces;

a light polarizing layer;

a mounting support including an electrical portion and an optical waveguide portion, with the optical waveguide portion having a light input surface, a light output surface, and a mirrored surface for directing light from the light input surface toward the light output surface, the polarizing layer and the reflective liquid crystal spatial light modulator stack being mounted on the light input surface of the mounting support;

a light source mounted in the mirrored surface of the optical waveguide portion and positioned to direct light through the polarizing layer and onto the reflective liquid crystal spatial light modulator stack with the light source spaced from the reflective liquid crystal spatial light modulator stack, so that light from the light source substantially evenly illuminates the reflective liquid crystal spatial light modulator stack, the array of reflective liquid crystal spatial light modulator stack being positioned so that reflected light from the reflective liquid crystal spatial light modulator stack is directed through the polarizing layer, into the light input surface and onto the mirrored surface through the optical portion;

a diffuser mounted in overlying relationship to the light output surface of the optical waveguide portion of the mounting support to form an image plane for reflected light from the reflective liquid crystal spatial light modulator stack; and

the electrical portion of the mounting support including leads formed in the electrical portion so as to be in electrical contact with the control terminals adjacent an outer edge of the substrate of each control circuit and the leads further extend to an external portion of the mounting support to form external contacts for the control circuits.

20. A method of fabricating an integrated electro-optic package for reflective spatial light modulators comprising the steps of:

providing a stack including a plurality of reflective spatial light modulators formed in a two dimensional array on a semiconductor substrate with drive electronics formed in the substrate for each spatial light modulator of the array of spatial light modulators and control terminals for the drive electronics positioned adjacent outer edges of the substrate, the stack further including a light transparent surface defining a light input and light output for each of the spatial light modulators in the two dimensional array of reflective spatial light modulators;

forming a mounting support including an electrical portion and an optical waveguide portion, with the optical waveguide portion having a light input surface, a light output surface, and a mirrored surface for directing light from the light input surface toward the light output surface, the polarizing layer and the stack being mounted on the light input surface of the mounting support, the electrical portion being formed to include a plurality of electrical leads each positioned therein so as to provide a first internal electrical contact in electrical communication with the control terminals for the drive electronics and a second, electrical contact at an external surface of the mounting support;

providing a light polarizing layer and positioning the light polarizing layer in overlying relationship to the light input surface of the mounting support;

positioning the stack in overlying relationship to the polarizing layer;

mounting a light source in the mirrored surface of the optical waveguide portion and positioning the light source to direct light through the polarizing layer and onto the stack with the light source spaced from the stack, so that light from the light source substantially evenly illuminates the stack, the stack being positioned so that reflected light from the stack is directed through the polarizing layer, into the light input surface and onto the mirrored surface through the optical portion; and

diffusing light reflected from the stack to form an image.

21. A method of fabricating an integrated electro-optic package for reflective spatial light modulators as claimed in claim 20 wherein the step of diffusing includes mounting a diffuser in overlying relationship to the light output surface of the mounting support to form an image plane for light reflected from the stack and passing through the polarizing layer and the optical waveguide portion of the mounting support.

22. A method of fabricating an integrated electro-optic package for reflective spatial light modulators as claimed in claim 20 wherein the step of forming a mounting support includes molding the mounting support from plastic.

23. A method of fabricating an integrated electro-optic package for reflective spatial light modulators as claimed in claim 22 wherein the step of molding the mounting support from plastic includes a step of molding a leadframe into the plastic to form the plurality of electrical leads.

24. A method of fabricating an integrated electro-optic package for reflective spatial light modulators as claimed in claim 23 wherein the step of molding the mounting support from plastic and the step of mounting a light source in the mirrored surface include forming the mounting support with an angled surface spaced from the light input surface and in a generally opposed relationship thereto and positioning at least one light emitting diode and forming a mirror on the angled surface.