US 6,556,348 B1 · Multibeam optical system

Abstract

A multibeam optical system that employs a multiline laser source emitting a laser beam at predetermined wavelengths, such as, for example, at wavelengths 488.0 nm and 514.5 nm, and a diffractive beam-dividing element having diffractive grating to divide the incident beam into nine diffracted beams. A design wavelength λM of the diffraction grating, at which the light quantity of the incident beam is equally distributed among the plurality of diffracted beams, is determined so as to satisfy the condition 488.0 nm<λM<514.5 nm. When the design wavelength λM is 501.1 nm, the light quantities of the divided beams, which are the sums of the quantities of the peak wavelengths 488. 0 nm and 514.5 nm, become nearly equal to one another among the nine diffraction orders. As a result, the distribution of the light quantities among the diffracted beams are balanced.

Claims9

Dependent claims

A multibeam optical system, comprising:

a multiline laser source that emits a laser beam having a plurality of peak wavelengths;
and
a diffractive beam-dividing element that diffracts the laser beam emitted from said laser source into a plurality of diffracted beams exiting at different diffraction angles, respectively, each of the plurality of diffracted beams having different wavelength components,
wherein said diffractive beam-dividing element is configured such that the sums of the light quantities of the wavelength components for each diffracted beam, are substantially equal.

1 more element

A multibeam optical system, comprising:

a multiline laser source that emits a laser beam having a plurality of peak wavelengths;
and
a diffractive beam-dividing element that diffracts the laser beam emitted from said laser source into a plurality of diffracted beams exiting at different diffraction angles, respectively, each of the plurality of diffracted beams having different wavelength components,
wherein said diffractive beam-dividing element is configured such that the sums of the light quantities of the wavelength components, for each diffracted beam are substantially equal, and
wherein said diffractive beam-dividing element is provided with a diffraction grating having a corrugated surface consisting of a plurality of periodical phase patterns arranged in parallel at a predetermined fixed pitch, and wherein said diffraction grating is designed such that the following conditions are satisfied:
SDN<SDS
SDN<SDL
where
SDS is a standard deviation of the beams diffracted by said diffractive beam-dividing element at the shortest peak wavelength λS among said plurality of peak wavelengths;
SDL is a standard deviation of the beams diffracted by said diffractive beam-dividing element at the longest peak wavelength λL among said plurality of peak wavelengths;
and
SDN is the standard deviation of the beams diffracted by said diffractive beam-dividing element at the peak wavelength λN that satisfies λS<λN<λL.

9 more elements

Dependencies are inferred from the claim text.

Multibeam optical system

Life of this patent

Multibeam optical system

Life of this patent

Abstract

Claims9