Laser projector and image projection method for projecting an image with reduced speckles on the projected laser light image
AssigneeKonica Minolta Opto, Inc.
InventorKenji Konno
Life of this patent
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Abstract
A laser projector comprises an oscillation device for displacing at least one of a plurality of optical elements, which constitute the projection optical system of the laser projector, periodically along the direction of the optical axis of laser light. The laser projector reduces the speckle of a projection image on an arbitrary screen to such an extent as it cannot be recognized with human eyes, without having a significant effect on the image resolution, by periodically displacing the position of the smallest spot of laser light projected from the projection optical system. An image projection method is also provided.
Claims14
A laser projector, comprising:
- a laser light source;
- a projection optical system including a plurality of optical elements to converge and project a laser light from the laser light source to a screen;
- and
- a vibration device for cyclically displacing at least one optical element of the plurality of optical elements along an optical axis direction of the laser light so that a position of a minimum spot of the converged laser light displaces in the optical axis direction of the laser light at the screen,
- wherein the following relationship is satisfied:
- W<Δ<πW2/(2λ)
- where:
- Δ is an amount of displacement of the position of the minimum spot, which displacement is caused by the cyclic displacement of the optical element;
- W is a spot size of the minimum spot of the laser light;
- λ is a wave length of the laser light;
- and
- π is the circular constant.
Dependencies are inferred from the claim text.