Microvision, Inc.

Alban N Lescure

Mark O Freeman

Markus Stefan Duelli

Christian Dean DeJong

Witold R Teller

Karlton David Powell

Joshua Mark Hudman

Joshua Owen Miller

Lansing B Evans

A bifocal head-up display system includes a projector, at least one projection surface in an intermediate image plane, and relay optics to direct a display image to a reflector in a vehicle operator's field of view. The display image includes two image portions focused at different distances from the vehicle operator. A first image portion focused at a first distance may include information related to vehicle operation, and a second image portion focused at a second distance may include to information related to extra-vehicular objects.

Bifocal head-up display system

A laser-based imaging system () is configured to reduce perceived speckle in images (). The imaging system () includes one or more laser sources (), a light modulator () configured to produce the images () with light () from the laser sources (), and one or more active polarization switches () disposed in an optical path of the imaging system (). The active polarization switch () is configured to alternate a polarization orientation of the light in synchrony with an image refresh cycle of the system. The active polarization switch can be clocked in accordance with a clocking angle to optimize speckle reduction. Additionally, one or more light preconditioners () may be used to help optimize speckle reduction.

Active polarization switch for speckle reduction in laser projection sources

An imaging system (), such as a scanned laser projection system, includes one or more laser sources () configured to produce one or more light beams (), and a light modulator () configured to produce images () from the light beams (). Optional optical alignment devices () can be used to orient the light beams () into a combined light beam (). A beam separator (), which can be any of a birefringent wedge, compensated birefringent wedge, or a polymerized liquid crystal layer, is disposed between at least one of the laser sources () and the light modulator (). The beam separator () is configured to receive light from the laser sources () and deliver two angularly separated and orthogonally polarized light beams () to the light modulator () so as to reduce speckle appearing when the images () are displayed on a display surface ().

Scanned projection system using polymerized liquid crystal layer for speckle reduction

An imaging system () is configured to reduce perceived speckle () in images () by introducing angular diversity into consecutively projected images. The imaging system () includes one or more laser sources () that are configured to produce one or more light beams (). A light modulator () scans these light beams () to produce images. A light translation element () introduces the angular diversity by physically altering a light reception location () on the light modulator () between refresh sweeps. To preserve image stability, image data () in a memory () can be correspondingly shifted.

Laser scanning imaging system with reduced speckle

An imaging system (), such as a scanned laser projection system, includes one or more laser sources () configured to produce one or more light beams (), and a light modulator () configured to produce images () from the light beams (). A polarization diversity element (), which can be manufactured from a birefringent material or from a polymerized liquid crystal layer, is disposed within the imaging system (). The polarization diversity element () is configured to alter the polarization of an incident beam to create a transmitted beam comprising diverse polarization patterns, thereby reducing speckle in projected images.

Laser projection source with polarization diversity element for speckle reduction

Briefly, in accordance with one or more embodiments, beam position diversity or beam offset diversity in pupil space performs the complement to angular diversity by maintaining angular content of a beam while changing its position and/or polarization properties in pupil space over time.

Apparent speckle reduction via beam offset diversity in pupil space

A optical apparatus () for use in an laser imaging system () is provided. The optical apparatus () includes one or more optical elements () that are configured to create an intermediate image plane () in the laser imaging system (). A diffractive optical element () is then disposed at the intermediate image plane () to reduce speckle. The diffractive optical element () includes a periodically repeating phase mask () that can be configured in accordance with steps, vortex functions, Hermite-Gaussian functions, and so forth. Smooth grey-level phase transitional surface () can be placed between elements () to improve brightness and image quality. The periodically repeating phase mask () makes manufacture simple by reducing alignment sensitivity, and can be used to make applicable safety standards easier to meet as well.

Diffractive optical element having periodically repeating phase mask and system for reducing perceived speckle

An imaging system (), such as a scanned laser projection system, includes one or more laser sources () configured to produce one or more light beams (), and a light modulator () configured to produce images () from the light beams (). Optional optical alignment devices () can be used to orient the light beams () into a combined light beam (). A birefringent wedge () is disposed between at least one of the laser sources () and the light modulator (). The birefringent wedge () is configured to receive light from the laser sources () and deliver two angularly separated and orthogonally polarized light beams () to the light modulator () so as to reduce speckle appearing when the images () are displayed on a display surface (). An optional glass wedge () can be used to correct optical path deviation () introduced by the birefringent wedge ().

Laser projection source with birefringent wedge for speckle reduction

An image producing system () delivers images () having reduced speckle by employing one or more drive circuits () that deliver both a direct current drive signal () and an alternating current drive signal () to one or more lasers (). Specifically, an alternating current drive circuit () is used in conjunction with a direct current drive circuit () to modulate a drive signal. The modulation can be at a frequency of between 400 MHz and 600 MHz. When lasers, such as the red laser () or the blue laser () of a multi-laser system are modulated in such a fashion, their emitted spectral widths () greatly expand, thereby reducing speckle in projected images ().

Growing community of inventors

Redmond, WA, United States of America

Alban N Lescure