Patrick D Thomas

US Patent:

6391528, May 21, 2002

Filed:

Apr 3, 2000

Appl. No.:

09/542256

Inventors:

Robert S. Moshrefzadeh - Oakdale MN
Patrick A. Thomas - Maplewood MN

Assignee:

3M Innovative Properties Company - St. Paul MN

International Classification:

G02B 530

US Classification:

430321, 430 1, 430 2, 117 92, 216 24, 359486, 359569, 427584, 427582, 427586, 427555

Abstract:

A method for making wire grid optical elements by preferentially depositing material on a substrate is disclosed. Material can be preferentially deposited by directing an electromagnetic interference pattern on to a substrate to selectively heat areas of the substrate coincident with the interference pattern maxima. The substrate can then be exposed to gas phase material that is capable of preferentially accumulating on surfaces based on surface temperature.

US Patent:

6407859, Jun 18, 2002

Filed:

Jan 13, 1999

Appl. No.:

09/229198

Inventors:

Daniel W. Hennen - Cottage Grove MN
Robert S. Moshrefzadeh - Oakdale MN
John C. Nelson - Thesea Ranch CA
Scott M. Tapio - Falcon Heights MN
Patrick A. Thomas - Maplewood MN

Assignee:

3M Innovative Properties Company - St. Paul MN

International Classification:

G03B 2160

US Classification:

359454, 359457, 359742

Abstract:

The present invention is a screen, such as is used in back-lit projection screens, having a Fresnel lens laminated to another layer for support. The screen includes a Fresnel lens having an output surface, and a dispersing screen supportingly attached on a first side to the output surface of the Fresnel lens.

US Patent:

6417966, Jul 9, 2002

Filed:

Jul 7, 1999

Appl. No.:

09/348809

Inventors:

Robert S. Moshrefzadeh - Oakdale MN
Patrick A. Thomas - Maplewood MN
John C. Nelson - The Sea Ranch CA
Theodore W. Hodapp - St. Paul MN
Hsin-Hsin Chou - Woodbury MN
Richard J. Pokorny - Maplewood MN
Raghunath Padiyath - Woodbury MN

Assignee:

3M Innovative Properties Company - St. Paul MN

International Classification:

G03B 2160

US Classification:

359453, 359460

Abstract:

An optically dispersing film for a rear projection system includes reflecting surfaces disposed so as to reflect light passing therethrough into at least one dispersion plane. The reflecting surfaces are formed by structures, of a first refractive index, disposed within a layer of material having a second refractive index. The structures have light absorbing bases at the viewing side of the film. In some embodiments, the reflecting surfaces are disposed at one or more angles so as to reflect light into a number of different directions. In other embodiments, the layer of material having the second refractive index includes diffusing particles that diffuse the light. The film permits the asymmetric dispersion of image light in a rear projection system, so that the light may be selectively directed towards the viewer.

US Patent:

6449089, Sep 10, 2002

Filed:

Mar 23, 1999

Appl. No.:

09/274585

Inventors:

Robert M. Moshrefzadeh - St. Paul MN
Patrick A. Thomas - Maplewood MN
Hassan Sahouani - Hastings MN
Daniel Croswell - Brooklyn Park MN

Assignee:

3M Innovative Properties Company - St. Paul MN

International Classification:

G03B 2156

US Classification:

359454, 359460

Abstract:

Projection screen assemblies include one or more birefringent retarding layers and one or more polarizing layers. The retarding and polarizing layers reduce the unwanted reflection of ambient and image light. One embodiment of a screen assembly includes a dispersing layer having an input side to receive light from a light source and a first retarding layer disposed to alter the polarization of the light transmitted by the dispersing film. A first polarizer substantially transmits light received from the first retarding layer in a first polarization state and absorbs light received from the first retarding layer in a second polarization state orthogonal to the first polarization state.

US Patent:

6466368, Oct 15, 2002

Filed:

Apr 26, 2000

Appl. No.:

09/560267

Inventors:

Andrew J. Piepel - Hudson WI
Robert S. Moshrefzadeh - Oakdale MN
Patrick A. Thomas - Maplewood MN
Thomas R. Gehring - Mahtomedi MN

Assignee:

3M Innovative Properties Company - Saint Paul MN

International Classification:

G03B 2160

US Classification:

359456, 359452, 359453, 359455, 359460, 359619

Abstract:

A rear projection screen has one or more internal layers that reduce the speckle perceived by a viewer. A screen assembly has a light-source side and a viewing side. The assembly includes a screen layer to disperse light passing through the screen from the light source side and a matte surface disposed on the viewing side of the screen assembly to reduce ambient glare. A first speckle contrast reducing layer is disposed between the screen layer and the matte surface to reduce speckle formed at the matte surface.

US Patent:

6515798, Feb 4, 2003

Filed:

Jun 29, 2000

Appl. No.:

09/606642

Inventors:

Hsin-Hsin Chou - Woodbury MN
Patrick A. Thomas - Maplewood MN
Jeffrey C. Chang - North Oaks MN
Robert M. Moshrefzadeh - St. Paul MN

Assignee:

3M Innovative Properties Company - St. Paul MN

International Classification:

G03B 2160

US Classification:

359443, 359449

Abstract:

A rear projection screen assembly is described that includes a diffuser and a polarizer. The diffuser has particles dispersed within a binder. The particles and the binder have different refractive indices and are chosen such that the diffuser spreads light of an initial polarization state a cone of angles while substantially preserving the initial polarization state of the light. The diffuser also substantially depolarizing a portion of the light that is laterally scattered in the diffuser. The polarizer is disposed to receive light transmitted through the diffuser. The polarizer transmits light of the initial polarization state while absorbing a portion of the laterally scattered light that has a different polarization state. The resolution of the overall screen assembly may be made higher while also improving other characteristics of the screen assembly.

US Patent:

6624934, Sep 23, 2003

Filed:

Jun 18, 1999

Appl. No.:

09/335994

Inventors:

Robert S. Moshrefzadeh - Oakdale MN
John C. Nelson - The Sea Ranch CA
Patrick A. Thomas - Maplewood MN

Assignee:

3M Innovative Properties Company - St. Paul MN

International Classification:

G03B 2156

US Classification:

359457, 359460

Abstract:

Rear projection screens use lenticular lens films as light dispersing components. A single lenticular lens film includes lenticular lenses having different focal powers, or includes lenticular lenses formed in two dimensional patterns. The lenticular lens films improve the brightness uniformity over the entire screen as viewed by a viewer who is located at a specific position. The specific position is typically selected to be the most probable location of the viewer for the particular application.

US Patent:

6636355, Oct 21, 2003

Filed:

Dec 27, 2000

Appl. No.:

09/748977

Inventors:

Robert S. Moshrefzadeh - Oakdale MN
Steven J. Rhyner - St. Paul MN
Peter F. Cullen - Woodbury MN
Patrick A. Thomas - Maplewood MN
Richard J. Pokorny - Maplewood MN
John C. Nelson - The Sea Ranch CA

Assignee:

3M Innovative Properties Company - St. Paul MN

International Classification:

G03B 2156

US Classification:

359460, 359453, 359454, 359459

Abstract:

Disclosed is a rear projection screen that includes a plurality of tapered waveguides and a light absorbing layer disposed over the tops of the waveguides, but that does not completely fill the spaces between the waveguides, thereby forming an interstitial low index region under the light absorbing layer and between the waveguides. The low index interstitial region can include air or a material that has a lower index of refraction than the waveguide material. This rear projection screen construction can give rise to increased efficiency and higher contrast, as well as allow for more design freedom in constructing screens that have desired characteristics such as viewing angle, viewing asymmetry, and the like. Also disclosed are methods for making the described microstructured rear projection screen.