Method and apparatus for reducing laser speckle

A display apparatus for displaying a two dimensional image on a display screen comprising:

• a. a laser source controlled by electronic means and providing a laser output;
• b. a first optical arrangement cylindrically focusing the laser output in a focus line, the focus line having a focus width, the focus line located at a first image plane;
• c. a light valve array modulated by the electronic means, located in the first image plane, and configured to produce a linear array of pixels, the linear array of pixels forming a line image;
• d. a second optical arrangement for cylindrically focusing the focus line having the focus width in a second image plane;
• e. a wavefront modulator located in the second image plane and modulating a spatial phase across the focus width such that a phase modulated wavefront is formed across a line image width;
• and
• f. a third optical arrangement driven by the electronic means, the third optical arrangement projecting the line image onto the display screen and scanning the line image over the display screen such that the two dimensional image is formed on the display screen and further such that the phase modulated wavefront reduces laser speckle.

A display apparatus for displaying a two dimensional image on a display screen comprising:

• a. a laser source controlled by electronic means and providing a laser output;
• b. a first optical arrangement cylindrically focusing the laser output in a focus line, the focus line having a focus width, the focus line located in a first image plane;
• c. a grating light valve located in the first image plane, illuminated by the focus line, and modulated by the electronic means, the grating light valve producing a combination of diffracted light and reflected light arranged in a linear array of pixels, a diffracted portion of the linear array of pixels forming a line image;
• d. a second optical arrangement separating the diffracted portion from the combination of the diffracted light and the reflected light, the second optical arrangement imaging the line image in a second image plane;
• e. a wavefront modulator located in the second image plane and modulating a spatial phase across a line image width whereby a phase modulated line image is formed;
• f. a projection lens projecting the phase modulated line image whereby a projected line image is formed;
• and
• g. a scanning mirror assembly driven by the electronic means and scanning the projected line image over the display screen such that the two dimensional image is formed on the display screen and further such that the phase modulated line image reduces laser speckle.

A method of reducing laser speckle in a laser illuminated display system comprising the steps of:

• a. focusing a laser output in a line having a width;
• b. modulating the laser output along the line to produce a linear array of pixels, the linear array of pixels forming a line image having a line image width;
• c. modulating a spatial phase across the line image width such that a phase modulated wavefront is produced;
• d. projecting the line image onto a display screen;
• and
• e. scanning the line image over the display screen repeatedly such that a two-dimensional image is formed on the display screen and further such that the phase modulated wavefront reduces the laser speckle.

A method of reducing laser speckle comprising the steps of:

• a. focusing a laser output in a line illumination having a line illumination width;
• b. modulating a spatial phase across the line illumination width such that a phase modulated wavefront is produced;
• c. projecting the line illumination onto a diffuse surface;
• and
• d. scanning the line illumination over the diffuse surface such that an area is illuminated and further such that the phase modulated wavefront reduces laser speckle.