Integrated electro-optic package for reflective spatial light modulators

• US 5,467,215 A
• Filed: 12/21/1994
• Issued: 11/14/1995
• 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): Hellner, Mark
• Application Number:
  US08/360,510
• Time in Patent Office: 328 Days
• Field of Search: 359/247, 359/263, 359/252, 359/253, 359/53, 359/54, 359/55, 359/62, 359/83, 359/69, 359/70
• US Class Current: 359/247
• CPC Class Codes: G02F 1/133308 Support structures for LCD panels, e.g. frames or bezels
• CPC Class Codes: G02F 2203/02 reflective
• CPC Class Codes: G02F 2203/12 spatial light modulator

Abstract

An array of reflective LCSLM pixels formed on a substrate with a light polarizing layer positioned in overlying relationship to the array. A light source mounted in an optically clear support positioned in overlying relationship to and spaced from the array, so that light evenly illuminates the array through the support and allows passage of reflected light from the array back through the support. Electrical connections are made from the array, through leads in the support and to external contacts. A diffuser mounted in overlying and spaced relationship to the support to form an image plane for reflected light from the array.

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 light source mounted in an optically clear support positioned in overlying relationship to 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 and allows passage of reflected light from the array of reflective spatial light modulator pixels through the optically clear support; and

a diffuser mounted in overlying relationship to the optically clear 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 the optically clear 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 the optically clear 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 plurality of light emitting diodes.

6. An integrated electro-optic package for reflective spatial light modulators as claimed in claim 5 wherein the plurality of light emitting diodes includes at least two diode, 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 optically clear 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 liquid 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 including in addition a housing having the light source and the optically clear support mounted therein, with the diffuser being removeably mounted and further mounted for axial movement toward and away from the optically clear support to provide focusing of images formed on the diffuser.

15. An integrated electro-optic package for reflective spatial light modulators as claimed in claim 1 including in addition a housing including leads formed therein 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.

16. An integrated electro-optic package for reflective spatial light modulators as claimed in claim 15 wherein the housing is molded and the leads are a leadframe molded into the housing.

17. 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 electrically conductive optically transparent layer of material;

a light source mounted in an optically clear support positioned in overlying relationship to 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 and allows passage of reflected light from the reflective liquid crystal spatial light modulator stack through the optically clear support; and

a diffuser mounted in overlying and spaced relationship to the optically clear support to form an image plane for reflected light from the reflective liquid crystal spatial light modulator stack.

18. An integrated electro-optic package for reflective liquid crystal spatial light modulators as claimed in claim 17 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.

19. An integrated electro-optic package for reflective liquid crystal spatial light modulators as claimed in claim 18 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.

20. 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;

an optically clear support having defined therein a cavity formed to receive the reflective liquid crystal spatial light modulator stack in nesting engagement, the optically clear support further including a plurality of electrical leads each formed therein so as to provide a first contact in the cavity and a second contact at an external surface of the optically clear support;

a light polarizing layer positioned in the cavity of the optically clear support;

the reflective liquid crystal spatial light modulator stack being nestingly positioned in the cavity so that the polarizing layer is positioned in overlying relationship to the electrically conductive optically transparent layer of material;

a light source mounted in the optically clear support and positioned in overlying relationship to 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 passes through the polarizing layer, substantially evenly illuminates the reflective liquid crystal spatial light modulator stack, and allows passage of reflected light from the reflective liquid crystal spatial light modulator stack through the polarizing layer and the optically clear support; and

a diffuser mounted in overlying and spaced relationship to the optically clear support to form an image plane for reflected light from the reflective liquid crystal spatial light modulator stack which passes through the polarizing layer and the optically clear support.

21. 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 an optically clear support having defined therein a cavity formed to receive the reflective spatial light modulator stack in nesting engagement with a lower surface of the cavity substantially parallel with and adjacent to the light transparent surface of the stack, the optically clear support further being formed to include a plurality of electrical leads each positioned therein so as to provide a first contact in the cavity and a second, electrically coupled contact at an external surface of the optically clear support;

providing a light polarizing layer and positioning the polarizing layer in the cavity of the optically clear support;

positioning the stack nestingly in the cavity so that the polarizing layer is positioned in overlying relationship and adjacent to the light transparent surface of the stack;

mounting a light source in the optically clear support and positioning the light source in overlying relationship to the light transparent surface of the stack with the light source spaced from the light transparent surface of the stack, so that light from the light source passes through the polarizing layer, substantially evenly illuminates the light transparent surface of the stack, and allows passage of reflected light from the light transparent surface of the stack through the polarizing layer and the optically clear support; and

diffusing light reflected from the stack to form an image.

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

23. A method of fabricating an integrated electro-optic package for reflective spatial light modulators as claimed in claim 21 wherein the step of forming an optically clear support includes molding the optically clear support from plastic.

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 optically clear support from plastic includes a step of molding a leadframe into the plastic to form the plurality of electrical leads.

25. A method of fabricating an integrated electro-optic package for reflective spatial light modulators as claimed in claim 24 wherein the step of molding the optically clear support from plastic and the step of mounting a light source in the optically clear support include forming the optically clear support with a second surface spaced from the lower surface of the cavity and on a side opposite thereto and embedding at least one light emitting diode into the second surface.