3 4
The spatial beam integrator preferably comprises a plu- FIG. 4 is an end view of the preferred embodiment of the
rality of hexagonal prisms distributed about a center, with invention;
each prism having a light outlet face for refracting an FIGS. 5A and 5B together constitute a schematic diagram
emerging portion of the collimated beam towards the center of a laser beam optical delivery system incorporating the
of the prism assembly, each light outlet face being preferably 5 invention; and
positioned at an angle with respect to a body axis passing mG 5C juustrates the relative orientation of FIGS. 5A
through the center of the spatial beam integrator. The center and 53
may comprise either a hollow space or an optical element nG/ 6 fc a schematic & of a t ^ ^am
such as a pnsm having a flat light outlet face. integrator uging ^ lenses of meieat focal
The apparatus further preferably includes means for per- 1° iength. mitting initial relative rotation between the spatial beam
integrator and the cylindrical lenses in order to optimize the DETAILED DESCRIPTION OF THE
spatial characteristics of the collimated beam passing there- PREFERRED EMBODIMENTS
through. The invention further may include an expanding Turning now to the drawings. FIG. 1 illustrates in sche
lens. preferably a spherical lens, positioned in the path of the 15 matic form a laser delivery apparatus according to the
beam emerging from the downstream one of the pair of invention. As seen in this figure, a collimated beam 10 from
cylindrical lenses, preferably between that lens and the a lasgr source (nQt shown) is onto me Met face of
spatial beam integrator. a tempos beam integrator generally designated with refer
The first means for rotating the cylindrical lenses about ence numeral 12. In the preferred embodiment of FIG. 1,
the beam axis preferably includes a housing for mounting 20 temporal beam integrator 12 includes a pair of substantially
the cylindrical lenses in proper alignment, a motor for identical cylindrical lenses 13.14 each arranged in the path
generating mechanical motion, and means for transferring 0f beam 10 and spaced along the beam axis by a distance
the mechanical motion to the housing. The transferring equal to the sum of the focal distances of the lenses. The
means preferably comprises a driving gear coupled to the cylindrical axes 15 of each of the lenses 13.14 are aligned
motor and a driven gear coupled to the housing and eng- 25 with respect to each other, and each lens is arranged with the
agable with the driving gear. The means for providing flat faCe normal to the beam axis, with the optical center of
relative rotation between the spatial beam integrator and the each lens 13.14 coincident with the beam axis. The convex
cylindrical lenses preferably comprises a second housing for cylindrical surface of lens 13 provides the inlet face for
mounting the spatial beam integrator, a motor for generating temporal beam integrator 12, while the convex face of
mechanical motion, and means for transferring the mechani- 30 cylindrical lens 14 forms the outlet face of the temporal
cal motion to the second housing, the transferring means beam integrator.
preferably comprising a driving gear coupled to the motor As suggested by broken Hne 17, cylindrical ienses 13,14 and a driven gear coupled to the housing and engagable with ^ mechanically linked, and as suggested by circular arrow the driving gear. The motor is preferably a single motor 18 ... lenses 13 and 14 are mounted for synchroshared between the first rotating means and the providing nous rotation about ±e beam ^ a beam 10 passes
means- through temporal beam integrator 12 as the lenses 13,14 are
In an alternate embodiment of the invention, the spatial rotated in unison, the rotated beam emerging from the outlet
beam integrator is rotated at the same rate as the cylindrical face of lens 14 is rotated twice for each complete revolution
lenses. In another alternate embodiment, the spatial beam 0f the lens pair 13, 14.
integrator is fixed and the cylindrical lenses are rotated. In 40 ^ optional beam eXpanding iens 20 is positioned in the
both of the alternate embodiments, the angular position of m of me rotated emerging from the temporal beam
the rotated beam with respect to the spatial beam integrator integrator 12 and is used to expand the beam size in those
varies with respect to time; while in the preferred applications requiring such beam expansion,
embodiment, the angular position of the rotated beam is A .. , . • * „ . u A ■ * J -*u r
- . ... 45 A spatial beam integrator generally designated with ref
fixed with respect to the spatial beam integrator. . . , ^ . ,.„ ° . ,
ft- &■ erence numeral 25 is located in the path of the rotating beam
The invention provides both spatial and temporal integra- emerging from temporal beam integrator 12 (and optionally
tion for a collimated laser beam and is substantially less emerging from the optional beam expander lens 20). Spatial
sensitive to misalignment of the temporal beam integrator beam integrator 25 comprises a close packed array of
with respect to the beam axis. In particular, any off axis 5Q hexagonal prisms 27 clustered about the center 26 of spatial
misalignment results in multiplication by a factor of beam integrator 25. As shown in FIG. 2, the outlet face 28
approximately 0.5 times the offset, due to the use of the of ^ of me prisms 27 is angled with respect to the central
refraction principle of the cylindrical lenses, which com- axis 29 of the spatial beam integrator. As a consequence, that
pares favorably to the multiplication factor of 2 encountered portion 0f the rotated laser beam passing through each prism
with temporal beam integrators employing dove prisms. J5 is refracted towards the central axis upon emergence from
For a fuller understanding of the nature and advantages of the outlet face 28. The spatially integrated beam emerging
the invention, reference should be had to the ensuing from spatial beam integrator 25 is transmitted to follow on
detailed description taken in conjunction with the accom- optical elements and to the destination site or plane,
panying drawings. As SUggested by curved arrow 32, spatial beam integrator
BRIEF DESCRIPTION OF THE DRAWINGS 60 ^ mounted for rotational movement about the beam
axis. In the preferred embodiment, spatial beam integrator
FIG. 1 is a schematic diagram of a portion of a laser beam 25 is mounted for rotation in the same angular direction as
optical delivery system incorporating the invention; temporal beam integrator 12, but at twice the rotational rate
FIG. 2 is a schematic sectional view taken along lines of the temporal beam integrator 12. Thus, the rotated beam
2—2 of FIG. 1 of a portion of the spatial beam integrator; 65 emerging from the temporal beam integrator 12 has a fixed
FIG. 3 is a sectional view of a preferred embodiment of angular orientation with respect to spatial beam integrator 25
the invention taken along lines 3—3 of FIG. 4; (since the beam is rotated by a factor of 2 in passing through
