1. A method of machining a groove in a workpiece by applying a laser beam emitted from a laser oscillator to the workpiece, comprising the steps of:
converging the laser beam emitted from the laser oscillator coaxially with the axis of an inner cylindrical surface of the workpiece, with a condenser lens;
thereafter, reflecting the laser beam substantially at a right angle to said axis with a mirror which is slanted a predetermined angle to said axis;
applying the reflected laser beam substantially perpendicularly to said inner cylindrical surface;
ejecting a gas to said inner cylindrical surface which is irradiated with said laser beam; and
displacing the laser oscillator and the mirror in unison along said axis while said laser beam is being applied to said inner cylindrical surface, thereby forming a pair of grooves straightly in and along said axis of said inner cylindrical surface.
2. A method according to claim 1, wherein after a first groove of said grooves is formed in said inner cylindrical surface of said workpiece, said mirror is turned 180\xb0 about said axis, and the said laser beam is applied to said inner cylindrical surface, thereby forming a second groove of said grooves straightly in and along said axis of said inner cylindrical surface facing said first groove.
3. A method according to claim 1, wherein said laser beam is divided into two laser beams by said mirror to form said pair of grooves substantially simultaneously in said inner cylindrical surface.
4. A method according to claim 1, wherein said gas is supplied to said inner cylindrical surface through a body housing said laser oscillator therein, and is also supplied to said inner cylindrical surface through a gas tube extending substantially parallel to an axis of said body.
5. A method according to claim 4, wherein said laser beam which is reflected substantially at the right angle to said axis with said mirror is applied to said inner cylindrical surface through an emission hole which is defined in said body facing said inner cylindrical surface.
6. A method according to claim 5, wherein said gas which is supplied through said body is ejected from said emission hole to said inner cylindrical surface.
7. A method according to claim 1, wherein said mirror has a mirror surface for reflecting said laser beam, said mirror surface being slanted 45\xb0 with respect to said axis toward said inner cylindrical surface.
8. A method according to claim 1, wherein said grooves have an acute-angled shape of a substantially V-shaped cross section.
9. A method according to claim 8, wherein said grooves have a width ranging from 0.1 to 0.4 mm in the circumferential direction of said inner cylindrical surface and a depth ranging from 0.2 to 0.7 mm in the radial direction of said inner cylindrical surface.
10. An apparatus for machining a groove in a workpiece by applying a laser beam emitted from a laser oscillator to the workpiece, comprising:
a condenser lens for converging the laser beam emitted from the laser oscillator coaxially with the axis of an inner cylindrical surface of the workpiece;
a mirror having a mirror surface which is slanted a predetermined angle to said axis, for reflecting the laser beam which is converged by said condenser lens; and
a gas tube for ejecting a gas to said inner cylindrical surface which is irradiated with said laser beam;
wherein said laser beam is reflected at a substantially right angle to said axis by said mirror, and applied to said inner cylindrical surface, thereby forming a pair of grooves in said inner cylindrical surface along said axis.
11. An apparatus according to claim 10, wherein said mirror has a mirror surface for reflecting said laser beam, said mirror surface being slanted 45\xb0 with respect to said axis toward said inner cylindrical surface.
12. An apparatus according to claim 10, wherein said mirror has a pair of mirror surfaces for reflecting said laser beam, each of said mirror surfaces being slanted 45\xb0 with respect to said axis toward said inner cylindrical surface.
13. An apparatus according to claim 10, wherein said gas tube is connected to a body housing said laser oscillator therein, and extends substantially parallel to an axis of said body.
14. An apparatus according to claim 13, wherein said body has an emission hole defined therein facing said inner cylindrical surface, for emitting therethrough the laser beam reflected at the substantially right angle by said mirror.
15. An apparatus according to claim 14, wherein said gas which is supplied from said gas tube through said body is ejected from said emission hole to said inner cylindrical surface of said workpiece.
16. An apparatus according to claim 10, wherein said grooves have an acute-angled shape of a substantially V-shaped cross section.
17. An apparatus according to claim 16, wherein said grooves have a width ranging from 0.1 to 0.4 mm in the circumferential direction of said inner cylindrical surface and a depth ranging from 0.2 to 0.7 mm in the radial direction of said inner cylindrical surface.
18. An apparatus according to claim 10, wherein said mirror is made of tungsten or molybdenum, or has a surface covered with a layer of tungsten or molybdenum.
19. An apparatus according to claim 10, wherein said gas comprises any one of air, nitrogen, argon, and oxygen.
20. An apparatus according to claim 10, wherein said laser beam comprises a CO2 laser beam or a YAG laser beam, and is continuously modulated or pulse-modulated at a frequency of at least 100 Hz.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1-9. (canceled)
10. A treatment apparatus for surgical correction of hyperopia in an eye, the treatment apparatus comprising:
a laser device which is controlled by a control device and which separates corneal tissue by applying laser radiation;
the control device controlling the laser device to emit the laser radiation into the cornea such that a lenticular volume is isolated in the cornea, the lenticular volume being structured such that removal of the volume effects a desired correction of hyperopia;
the control device controlling the laser device such that the laser device defines the lenticular volume to have a posterior face and an anterior face and edges that are connected via an annular edge face, the edge face having, in projection along an optical axis of the eye, a first ring width that is greater than a second ring width that would be created in the projection along the optical axis of the eye by a straight line extending perpendicularly from an edge of the posterior or the anterior face to the other of the posterior or the anterior face or to an imaginary continuation thereof.
11. The treatment apparatus according to claim 10, wherein the anterior face is positioned at a constant distance dF from the anterior surface of the cornea and the posterior face is curved and has a radius of curvature RL=RCV*\u2212dF, wherein RCV* satisfies the following equation
RCV*=1((1RCV)+BBR((nc\u22121)\xb7(1\u2212dHS\xb7BBR)))+F,
and RCV is a radius of curvature of the cornea before removal of the volume, nc is a refractive index of a material of the cornea, F is a correction factor, BBR is a refractive power of a pair of spectacles suitable for correcting defective vision, and also dHS is a distance at which the pair of spectacles having the refractive power BBR would have to be positioned before a corneal apex in order to achieve a desired correction of defective vision by the pair of spectacles.
12. The apparatus or the method according to claim 11, wherein the following applies
F=(1\u22121nc)\xb7(dC*\u2212dC),
wherein dC and dC* respectively denote a thickness of the cornea before and after removal of the volume and the radius RCV* can be calculated iteratively in that during each iteration step a change in thickness (dC*\u2212dC) is concluded from the difference (RCV*\u2212RCV) and the corresponding result obtained therefrom for the change in thickness is applied in the calculation of RCV* in a next iteration step.
13. The apparatus according to claim 10, wherein the edge face has a first portion opening substantially perpendicularly into the anterior face and a second portion inclined more acutely toward the axis of vision.
14. The apparatus or the method according to claim 13, wherein the first portion has a height dR of more than 5 \u03bcm,
15. The apparatus or the method according to claim 13, wherein the first portion has a height dR of at least 10 \u03bcm.
16. The apparatus or the method according to claim 13, wherein the second portion is positioned at an angle of from 80\xb0 to 100\xb0 relative to the direction of the axis of vision.
17. The apparatus or the method according to claim 8, wherein the second portion is concave, based on the point at which the axis of vision passes through the front face of the cornea.
18. A method for generating control data for a laser device of a treatment apparatus for surgical correction of hyperopia in an eye, wherein the laser device separates corneal tissue by applying laser radiation and wherein the control data controls the laser device in operation for emitting the laser radiation into the cornea such that a lenticular volume is isolated in the cornea and the removal of the lenticular volume effects a desired correction of hyperopia, the method comprising:
generating the control data to define the lenticular volume to have a posterior face and an anterior face and edges that are connected via an annular edge face, the edge face having in projection along an optical axis of the eye a first ring width which is greater than a second ring width that would be created in the projection along the optical axis of the eye by a straight line extending perpendicularly from an edge of the posterior or the anterior face to the other of the posterior or the anterior face or to an imaginary continuation thereof.
19. The method according to claim 18, further comprising:
generating the control data such that the anterior face is positioned at a constant distance dF from the anterior surface of the cornea and the posterior face is curved and has a radius of curvature RL=RCV*\u2212dF, wherein RCV* satisfies the following equation
RCV*=1((1RCV)+BBR((nc\u22121)\xb7(1\u2212dHSi\u2212BBR)))+F,
and RCV is a radius of curvature of the cornea before removal of the volume, nc is a refractive index of a material of the cornea, F is a correction factor, BBR is a refractive power of a pair of spectacles suitable for correcting defective vision, and also dHS is a distance at which the pair of spectacles having the refractive power BBR would have to be positioned before a corneal apex in order to achieve a desired correction of defective vision by the pair of spectacles.
20. The method according to claim 19, further comprising generating the control data such that the following applies
F=(1\u22121nc)\xb7(dC*\u2212dC),
wherein dC and dC* respectively denote a thickness of the cornea before and after removal of the volume and the radius RCV* can be calculated iteratively in that during each iteration step a change in thickness (dC*\u2212dC) is concluded from the difference (RCV*\u2212RCV) and the corresponding result obtained therefrom for the change in thickness is applied in the calculation of RCV* in a next iteration step.
21. The method according to claim 18, further comprising generating the control data such that the edge face has a first portion opening substantially perpendicularly into the anterior face and a second portion inclined more acutely toward the axis of vision.
22. The method according to claim 21, further comprising generating the control data such that the first portion has a height dR of more than 5 \u03bcm,
23. The method according to claim 21, further comprising generating the control data such that the first portion has a height dR of of at least 10 \u03bcm.
24. The method according to claim 21, further comprising generating the control data such that the second portion is positioned at an angle of from 80\xb0 to 100\xb0 relative to the direction of the axis of vision.
25. The method according to claim 8, further comprising generating the control data such that the second portion is concave, based on the point at which the axis of vision passes through the front face of the cornea.
26. A method for surgical correction of hyperopia in an eye, wherein corneal tissue is separated by applying a laser radiation and a lenticular volume is thus isolated and removed from in the cornea, the removal of the lenticular volume effecting a desired correction of hyperopia, the method comprising:
generating the lenticular volume to have a posterior face and an anterior face, and edges that are connected via an annular edge face, the edge face having in projection along an optical axis of the eye a first ring width which is greater than a second ring width that would be created in the projection along the optical axis of the eye by a straight line extending perpendicularly from an edge of the posterior or the anterior face to the other of the posterior or the anterior face or to an imaginary continuation thereof.
27. The method according to claim 26, further comprising generating the lenticular volume such that the anterior face is positioned at a constant distance dF from the anterior surface of the cornea and the posterior face is curved and has a radius of curvature RL=RCV*\u2212dF, wherein RCV* satisfies the following equation
RCV*=1((1RCV)+BBR((nc\u22121)\xb7(1\u2212dHS\u2212BBR)))+F,
and RCV is a radius of curvature of the cornea before removal of the volume, nc is a refractive index of a material of the cornea, F is a correction factor, BBR is a refractive power of a pair of spectacles suitable for correcting defective vision, and also dHS is a distance at which the pair of spectacles having the refractive power BBR would have to be positioned before a corneal apex in order to achieve a desired correction of defective vision by the pair of spectacles.
28. The method according to claim 27, further comprising generating the lenticular volume such that the following applies
F=(1\u22121nc)\xb7(dC*\u2212dC),
wherein dC and dC* respectively denote a thickness of the cornea before and after removal of the volume and the radius RCV* can be calculated iteratively in that during each iteration step a change in thickness (dC*\u2212dC) is concluded from the difference (RCV*\u2212RCV) and the corresponding result obtained therefrom for the change in thickness is applied in the calculation of RCV* in a next iteration step.
29. The method according to claim 26, further comprising generating the lenticular volume such that the edge face has a first portion opening substantially perpendicularly into the anterior face and a second portion inclined more intensively toward the axis of vision.
30. The method according to claim 29, further comprising generating the lenticular volume such that the first portion has a height dR of more than 5 \u03bcm,
31. The method according to claim 29, further comprising generating the lenticular volume such that the first portion has a height dR of of at least 10 \u03bcm.
32. The method according to claim 29, further comprising generating the lenticular volume such that the second portion is positioned at an angle of from 80\xb0 to 100\xb0 relative to the direction of the axis of vision.
33. The method according to claim 32, further comprising generating the lenticular volume such that the second portion is concave, based on the point at which the axis of vision passes through the front face of the cornea.