Diffusion safety system
A power beaming system includes a power beam transmitter arranged to transmit the power beam, and a power beam receiver arranged to receive the power beam from the power beam transmitter. A power beam transmission source is arranged to generate a laser light beam for transmission by the power beam transmitter from a first location toward a remote second location. A beam-shaping element shapes the laser light beam, at least one diffusion element uniformly distributes light of the shaped laser light beam, and a projection element illuminates a power beam receiving element of predetermined shape with the shaped laser light beam. At the power beam receiver, a diffusion surface diffuses a portion the power beam specularly reflected from the power beam receiver.
1. A method of diffusing a power beam, comprising:
receiving the power beam at a power beam receiver; and
diffusing a specularly-reflected portion of the received power beam with a diffusion surface.
2. A method according to claim 1 , wherein the power beam receiver includes:
a photovoltaic arrangement having a surface positioned to receive at least a powering portion of the received power beam,
and wherein receiving the power beam at the power beam receiver includes receiving at least a portion of the power beam at the diffusion surface before receiving the received power beam at the photovoltaic arrangement.
3. A method according to claim 2 , wherein the diffusion surface is a diffuser attached proximate to the surface of the photovoltaic arrangement.
4. A method according to claim 2 , wherein diffusing a specularly-reflected portion of the received power beam includes diffusing light specularly reflected from the photovoltaic arrangement.
5. A method according to claim 2 , wherein:
receiving the power beam at the power beam receiver includes allowing at least a portion of the power beam to pass through a transparent covering before reaching the photovoltaic arrangement; and
the diffusion surface is a surface of the transparent covering.
6. A method according to claim 5 , wherein the transparent covering includes an antireflective coating on a surface distal from the at least one photovoltaic arrangement, the antireflective coating selected based on a wavelength of the power beam.
7. A method according to claim 2 , wherein the diffusion surface is a non-optical surface of the power beam receiver.
8. A method according to claim 2 , wherein:
the surface positioned to receive at least a powering portion of the received power beam is a surface of a component of the power beam receiver that is first to be struck by the power beam after its travel through free space.
9. A power beaming method, comprising:
generating a power beam for transmission from a transmission location to a receiving location, the receiving location being remote from the transmission location;
diffusing the power beam at the transmission location to produce a diffused power beam; and
projecting the diffused power beam toward the receiving location.
10. A method according to claim 9 , wherein generating the power beam includes generating the power beam using at least one light source selected from the group consisting of a diode laser, a gas laser, and a fiber laser, the power beam having a determined divergence.
11. A method according to claim 10 , wherein the determined divergence is different in vertical and horizontal directions.
12. A method according to claim 9 , wherein diffusing the power beam increases an apparent angular size (AAS) of the power beam.
13. A method according to claim 9 , wherein diffusing the power beam includes passing the power beam through a diffusion element.
14. A method according to claim 13 , wherein the diffusion element includes an element selected from the group consisting of:
an internally-reflective tube;
a diffractive optical element;
a plurality of diffractive optical elements; and
an arrangement of microlenses.
15. A method according to claim 9 , wherein diffusing the power beam produces a geometrically symmetric distribution of the diffused power beam.
16. A method according to claim 9 , wherein projecting the power beam includes passing the power beam through a projection lens selected from the group consisting of a zoom lens and a varifocal lens, the projection lens being selectably positionable to match the diffused power beam to a size, shape, and position of a receiving element at the receiving location.
17. A system to diffuse a power beam, comprising:
a power beam transmitter arranged to transmit the power beam; and
a power beam receiver arranged to receive the power beam from the power beam transmitter, the power beam receiver including a diffusion surface arranged to diffuse a portion of the power beam that has been reflected from a portion of the power beam receiver, the diffusion surface being positioned to be a surface of the initial component of the power beam receiver to receive the power beam.
18. A system according to claim 17 , wherein the diffusion surface is an outer surface of a transparent covering.
19. A system according to claim 17 , wherein the diffusion surface is arranged to diffuse a portion of the power beam that has been reflected from an element selected from the group consisting of:
a photovoltaic cell;
a concentrator;
a mirror;
a lens; and
the diffusion surface.
20. A system according to claim 17 , wherein the diffusion surface includes an element selected from the group consisting of:
an internally-reflective tube;
a diffractive optical element;
a plurality of diffractive optical elements;
an arrangement of lenses; and
an arrangement of microlenses.