Charles L Bruzzone

US Patent:

6381068, Apr 30, 2002

Filed:

Mar 19, 1999

Appl. No.:

09/272159

Inventors:

Takashi Harada - Machida, JP
Yorinobu Takamatsu - Kanagawa, JP
Makoto Ishikawa - Kanagawa, JP
Charles L. Bruzzone - Woodbury MN
Robert S. Moshrefzadeh - Oakdale MN
Timothy J. Nevitt - Minneapolis MN
Andrew J. Ouderkirk - Woodbury MN

Assignee:

3M Innovative Properties Company - St. Paul MN

International Classification:

G03B 2156

US Classification:

359443

Abstract:

Reflective front projection screens capable of projecting an image with enhanced contrast and a wide viewing angle in the presence of relatively high levels of ambient light are disclosed along with projection systems using the screens. The projection screens include a reflective polarizing element in combination with a diffusing element and/or glare suppressing element. The reflective polarizing element transmits light of one polarization state and reflects light of a different polarization state. The reflective polarizing element may be diffusely reflective or specularly reflective and the optical properties of the diffusing element and/or glare suppressing element may be selected based on the optical properties of the reflective polarizing element to further enhance image brightness and contrast. The projection systems preferably project an image using light of the polarization state that is reflected by the reflective polarizing element in the screen to further enhance brightness and contrast of the image.

US Patent:

6486997, Nov 26, 2002

Filed:

May 17, 1999

Appl. No.:

09/312917

Inventors:

Charles L. Bruzzone - Woodbury MN
David J. W. Aastuen - Farmington MN
Roger J. Strharsky - Woodbury MN
Stephen K. Eckhardt - Austin TX
Michael F. Weber - Shoreview MN
Gary T. Boyd - Woodbury MN

Assignee:

3M Innovative Properties Company - St. Paul MN

International Classification:

G02F 103

US Classification:

359247, 359250, 359253, 359256, 359495, 359497, 359500, 349 9, 353 20, 353 81

Abstract:

An optical imaging system including a wide-angle Cartesian polarizing beam splitter, light valve illumination optics having an f/#2. 5, and at least one reflective light valve. The Cartesian polarizing beam splitter (PBS) has a structural orientation defining fixed polarization axes. The use of a Cartesian PBS allows the development of systems using curved PBS that provide higher light output and/or replace or augment other optical components. By recognizing and advantageously applying properties of wide-angle Cartesian polarizers, the present invention discloses a high-efficiency optical imaging system capable of functioning at f/#s equal to or below f/2. 5 while maintaining a contrast ratio of at least 100 to 1, or, more preferably, 150 to 1 in a projection system configuration.

US Patent:

6525816, Feb 25, 2003

Filed:

Dec 28, 2000

Appl. No.:

09/750563

Inventors:

David J. W. Aastuen - Farmington MN
Charles L. Bruzzone - Woodbury MN

Assignee:

3M Innovative Properties Company - St. Paul MN

International Classification:

G01J 400

US Classification:

356364, 356368, 356369

Abstract:

A method for measuring the absolute throughput of a polarization modulating reflective display in an optical system having a folded light path. The steps include measuring a first light intensity, L , in the folded light path, having a first polarizing beam splitter, and a reflective display. A second intensity, L , is measured using an unfolded light path where the reflective display is replaced by a second cross-rotated polarizing beam splitter. The absolute throughput is T is calculated, where T =L /L.

US Patent:

6609795, Aug 26, 2003

Filed:

Jun 11, 2001

Appl. No.:

09/878575

Inventors:

Michael F. Weber - Shoreview MN
Charles L. Bruzzone - Woodbury MN
Peter D. Condo - Lake Elmo MN
Kevin M. Hamer - St. Paul MN
Timothy J. Hebrink - Oakdale MN
William W. Merrill - White Bear Lake MN

Assignee:

3M Innovative Properties Company - St. Paul MN

International Classification:

G03B 2100

US Classification:

353 20, 353 31, 353 33, 359494, 359495, 359496, 359500, 359580, 359586, 428212

Abstract:

The present invention provides a unique polarizing beam splitter (PBS) that is suitable for use in projection systems and displays. The PBS contains at least one prism having at least one major surface and having a refractive index of at least about 1. 6 and a birefringent film disposed on the major surface of the prism. The birefringent film is a multi-layer film having layers of at least a first material and a second material. After uniaxial stretching, the film exhibits a refractive index difference of less than about 0. 15 units in the stretched direction.

US Patent:

6672721, Jan 6, 2004

Filed:

Jun 11, 2001

Appl. No.:

09/878559

Inventors:

David J. W. Aastuen - Farmington MN
Charles L. Bruzzone - Woodbury MN
Stephen K. Eckhardt - Austin TX
Jiaying Ma - Maplewood MN

Assignee:

3M Innovative Properties Company - St. Paul MN

International Classification:

G03B 2100

US Classification:

353 31, 353 33, 353 20, 353 81

Abstract:

Generally, the present invention relates to an apparatus for reducing astigmatism in a projection system that is particularly well suited to reducing astigmatism in LCD projection systems. A projection system includes a light source to generate light, conditioning optics to condition the light from the light source and an imaging core to impose on image on conditioned light from the conditioning optics to form image light. The imaging core includes a polarizing beamsplitter and at least one imager, and at least one element in the imaging core is adapted to reduce astigmatism in the image light. The astigmatism may arise in the polarizing beamsplitter. A projection lens system projects the astigmatism-reduced image light from the imaging core.

US Patent:

6719426, Apr 13, 2004

Filed:

Feb 25, 2003

Appl. No.:

10/374221

Inventors:

Simon Magarill - Cincinnati OH
Charles L. Bruzzone - Woodbury MN
Stephen K. Eckhardt - White Bear Lake MN
E. Gregory Fulkerson - Amelia OH
Jiaying Ma - Maplewood MN
Todd S. Rutherford - Cincinnati OH

Assignee:

3M Innovative Properties Company - St. Paul MN

International Classification:

G03B 2128

US Classification:

353 20, 353 81

Abstract:

A compound polarization beam splitter ( ) for use with a reflective, polarization-modulating, imaging device ( ), e. g. , a LCoS device, is provided. The compound PBS has: (a) an input prism ( ); (b) an output prism ( ), and (c) a polarizer ( ), which is located between the two prisms ( ) and which may be a wire grid polarizer ( ) or a multi-layer reflective polarizer ( ). Polarized illumination light ( ) enters the input prism ( ) through a first surface ( ) and undergoes total internal reflection at a second surface ( ) before being reflected from the polarizer ( ) and polarization-modulated at the imaging device ( ). The polarizers tilt angle () is less than 45Â, which reduces astigmatism and the required back working distance of the systems projection lens ( ).

US Patent:

6721096, Apr 13, 2004

Filed:

Nov 15, 2002

Appl. No.:

10/295674

Inventors:

Charles L. Bruzzone - Woodbury MN
David J. W. Aastuen - Farmington MN
Roger J. Strharsky - Woodbury MN
Stephen K. Eckhardt - Austin TX
Michael F. Weber - Shoreview MN
Gary T. Boyd - Woodbury MN

Assignee:

3M Innovative Properties Company - St. Paul MN

International Classification:

G02B 530

US Classification:

359495, 359496, 359497, 359500

Abstract:

An optical imaging system including a wide-angle Cartesian polarizing beam splitter, light valve illumination optics having an f/#2. 5, and at least one reflective light valve. The Cartesian polarizing beam splitter (PBS) has a structural orientation defining fixed polarization axes. The use of a Cartesian PBS allows the development of systems using curved PBS that provide higher light output and/or replace or augment other optical components. By recognizing and advantageously applying properties of wide-angle Cartesian polarizers, the present invention discloses a high-efficiency optical imaging system capable of functioning at f/#s equal to or below f/2. 5 while maintaining a contrast ratio of at least 100 to 1, or, more preferably, 150 to 1 in a projection system configuration.

US Patent:

6786604, Sep 7, 2004

Filed:

May 29, 2002

Appl. No.:

10/159694

Inventors:

David J. W. Aastuen - Farmington MN
Charles L. Bruzzone - Woodbury MN
Jiaying Ma - Maplewood MN

Assignee:

3M Innovative Properties Company - St. Paul MN

International Classification:

G03B 2114

US Classification:

353 20, 353 31, 353 81

Abstract:

LCD projection systems that use reflective LCD imager units commonly use one or more polarization beamsplitters to separate the light incident on the imager from the light reflected by one or more respective imagers. The polarizing beamsplitters introduce astigmatism to the image light from the imagers. According to the present invention, the polarization beamsplitters are adapted to reduce the astigmatism.