Process and apparatus for the ablation of a surface
AssigneeCarl-Zeiss-Stiftung
InventorsWalter Wrobel, Theo Lasser, Peter Reimer, Herbert Gross, Willi Ulrich
Life of this patent
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Abstract
For defined ablation of a surface, successive partial regions of equal surface area are acted on by a radiation source, preferably a laser, through an optical system. The partial regions are smaller as regards surface area than the whole surface to be processed, so that the respective radiation source can be dimensioned in a less costly manner. Telescope optics with conical surfaces serve as optical systems suitable for this purpose.
Claims12
In a process for the ablation of a surface by means of electromagnetic radiation, wherein the surface to be processed is aligned centrally with respect to an optical axis, a radiation source emits pulses of electromagnetic energy along said optical axis and the region of the surface acted on by said electromagnetic radiation is adjustable in a defined manner by means of an optical system, the improvement comprising the steps of:
- acting on partial regions of constant area on said surface to be processed in successive sequence by said electromagnetic radiation,
- arranging said optical system in the beam path of said electromagnetic radiation to ensure the constancy of the surface area of each partial region acted on in each partial exposure,
- employing a radiation source having a maximum power that is adequate to deliver an electromagnetic energy density in said partial regions of constant area that is adequate to ablate said surface area of each partial region,
- monitoring actual ablation of said surface area of each partial region quantitatively,
- comparing said actual ablation with a desired reference ablation, and
- repeatedly adjusting said actual ablation to correspond to said reference ablation.
In a process for the ablation of a surface by means of electromagnetic radiation, wherein the surface to be processed is aligned centrally with respect to an optical axis, a radiation source emits pulses of electromagnetic energy along said optical axis and the region of the surface acted on by said electromagnetic radiation is adjustable in a defined manner by means of an optical system, the improvement comprising the steps of:
- acting on partial regions of constant area on said surface to be processed in successive sequence by said electromagnetic radiation, and
- arranging said optical system in the beam path of said electromagnetic radiation to ensure the constancy of the surface area of each partial region acted on in each partial exposure, this last mentioned step further comprising:
- employing along said optical axis in a direction of pulse propogation, a first, stationary optical element for providing a real or virtual image, a second optical element having a convergent conical surface, following said first optical element, which is displaceable along said optical axis, and a third optical element following said second optical element, which is displaceable along said optical axis and has a diverging optical action and a converging cone surface, and
- moving said second and third optical elements relative to each other, such that with the setting of optional beam cross-sectional parameters, the respective resulting beam cross-sectional area of the emergent beam is essentially constant.
Dependencies are inferred from the claim text.