What is claimed is:
1. A method of generating a treatment table for ablating tissue using a scanning laser beam for generating scanning spots over a treatment region larger in area than the scanning spots, the method comprising:
providing a target function representing a desired lens profile for ablating the tissue by scanning spots of the laser beam on the tissue;
providing a basis function representing a treatment profile produced by scanning with overlapping scanning spots of the laser beam din a treatment pattern; and
fitting the target function with the basis function to obtain a treatment table including scanning spot locations and characteristics for the overlapping scanning spots of the laser beam.
2. The method of claim 1 wherein the basis function is a two-dimensional function representing a two-dimensional section of a three-dimensional treatment profile which has symmetry with respect to the two-dimensional section extending along the treatment pattern.
3. The method of claim 2 wherein the treatment pattern is generally linear or generally circular.
4. The method of claim 1 wherein the target function is a two-dimensional function representing a two-dimensional section of a three-dimensional lens profile which has symmetry with respect to the two-dimensional section extending along the treatment pattern.
5. The method of claim 4 wherein the target function represents an ablation depth as a function of a distance from an optical axis of a cornea.
6. The method of claim 1 wherein fitting the target function with the basis function includes fitting at N discrete evaluation points.
7. The method of claim 6 wherein the basis function includes M discrete basis functions representing M overlapping scanning spots.
8. The method of claim 7 wherein the M discrete basis functions represent M overlapping scanning spots across a treatment zone length representing the length across a generally two-dimensional section which is oriented normal across a generally straight treatment pattern or which is oriented radially across a generally circular treatment pattern.
9. The method of claim 8 wherein the scanning spots are generally circular and have a generally uniform energy profile.
10. The method of claim 9 wherein
(A) for a treatment profile having a generally uniform two-dimensional section oriented normal across a generally straight treatment pattern, the discrete basis functions represent the two-dimensional section as
Xi(xj)yi(xj){square root}{square root over ((s2)2(xjx0i)2)} or
(B) for a treatment profile having a generally uniform two-dimensional section oriented radially across a generally circular treatment pattern, the discrete basis functions represent the two-dimensional section as
31
X
i
(
x
j
)
=
i
(
x
j
)
=
cos
–
1
(
x
j
2
+
x
0
i
2
–
(
s
2
)
2
2
x
0
i
x
j
)
where
s is the diameter of the scanning spot;
j1, . . . , N;
xj is a reference x-coordinate for the two-dimensional section measured from an optical axis of the cornea of a jth evaluation point for the center of the scanning spot;
x0i is an x-coordinate for a center of an ith scanning spot;
(x0is2)xj(x0is2);
yi(xj) is a depth of the ith basis function for the generally straight treatment pattern; and
i(xj) is a coverage angle of the ith basis function for the generally circular treatment pattern.
11. The method of claim 10 wherein x0i is specified for M number of equally spaced scanning spots as x0ii*(Lse)M,
where
L is the treatment zone length;
e is an extended zone; and
i1, . . . , M.
12. The method of claim 11 wherein e is set to about 0.1 to about 0.5 mm.
13. The method of claim 7 wherein M is equal to about 7 to about 97.
14. The method of claim 7 further comprising refitting the target function with the basis function by varying the number of scanning spots M to iterate for a best fit.
15. The method of claim 6 wherein the target function is:
(A) for myopia and myopic cylinder,
32
f
(
x
j
)
=
R
1
2
–
x
j
2
–
(
R
1
(
n
–
1
)
n
–
1
+
R
1
D
)
–
x
j
2
+
C
or
(B) for hyperopia and hyperopic cylinder,
33
f
(
x
j
)
=
R
1
–
R
1
(
n
–
1
)
n
–
1
+
R
1
D
–
R
1
2
–
x
j
2
+
(
R
1
(
n
–
1
)
n
–
1
+
R
1
D
)
–
x
j
2
or
(C) for phototherapeutic keratectomy,
f(xj)d;
where
0xj(Lshift);
j0, 1, . . . , N1;
34
C
=
R
1
2
–
s
2
4
+
(
R
1
(
n
–
1
)
n
–
1
+
R
1
D
)
–
s
2
4
;
xj is an x-coordinate measured from an optical axis of the cornea of the jth evaluation point for the center of the scanning spot;
s is the diameter of the scanning spot;
R1 is the anterior radius of curvature of the cornea in meters;
R2 is the final anterior radius of curvature of the cornea in meters;
n1.377 is the index of refraction of the cornea;
D is the lens power of the scanning spot in diopters;
L is the treatment zone length representing the length across a generally uniform section which is oriented normal across a generally straight treatment pattern for myopic or hyperopic cylinders, or which is oriented radially across a generally circular treatment pattern for myopia or hyperopia;
shift is the amount of emphasis shift; and
d is a constant depth.
16. The method of claim 15 wherein the shift is about 0 to about 0.2.
17. The method of claim 15 wherein xjj*(Lshift)N.
18. The method of claim 15 wherein the basis function includes M discrete basis functions representing M overlapping scanning spots, and wherein fitting the target function with the basis function comprises solving the following equation for coefficients ai representing treatment depth for the ith scanning spot:
35
f
(
x
j
)
=
i
=
1
M
a
i
X
i
(
x
j
)
where
Xi(xj) is the ith basis function; and
i1, . . . , M.
19. The method of claim 6 wherein fitting the target function and the basis function comprises specifying a deviation for each of the N discrete evaluation points.
20. The method of claim 19 further comprising refitting the target function with the basis function by varying the deviations to iterate for a best fit.
21. The method of claim 1 wherein fitting the target function and the basis function comprises evaluating closeness of the fit and repeating the fitting step if the closeness does not fall within a target closeness.
22. The method of claim 1 wherein the target function and the basis function are fitted using a least square fit.
23. The method of claim 1 further comprising randomizing the scanning spot locations of the treatment table to produce a random scanning order.
24. The method of claim 1 further comprising refitting the target function with the basis function by varying the size of at least one of the scanning spots to iterate for a best fit.
25. The method of claim 1 wherein the scanning spot characteristics of a scanning spot at a scanning spot location include shape, size, and depth of the scanning spot at the scanning location.
26. The method of claim 1 wherein the scanning spots have different sizes.
27. The method of claim 1 further comprising specifying the treatment pattern for scanning with overlapping scanning spots of the laser beam.
28. The method of claim 1 wherein the target function and the basis function are fitted using a simulated annealing process.
29. The method of claim 1 further comprising specifying a merit function representing an error of fit between the target function and the basis function; and minimizing the merit function.
30. The method of claim 1 further comprising specifying a merit function representing an error of fit between the target function and the basis function; monitoring a total number of the scanning spots in the treatment table; and minimizing the merit function and the total number of the scanning spots in the treatment table.
31. The method of claim 1 further comprising refitting the target function with the basis function by selecting a scanning spot location and varying the characteristics of the scanning spot at the selected location to iterate for a best fit.
32. A method of generating a treatment table for ablating tissue using a scanning laser beam for generating scanning spots over a treatment region larger in area than the scanning spots, the method comprising:
providing a lens function representing a desired lens profile for ablating the tissue by scanning spots of the laser beam on the tissue;
providing a basis function representing a treatment profile produced by the overlapping scanning spots along a treatment path, the basis function representing a section oriented across the treatment path; and
fitting the lens function with the basis function to obtain a treatment table including scanning spot locations and characteristics for the overlapping scanning spots of the laser beam.
33. The method of claim 32 wherein the scanning spots are generally circular and have a generally uniform energy profile, and the basis function includes M discrete basis functions representing M overlapping scanning spots.
34. The method of claim 33 wherein the treatment profile is symmetrical with respect to an axis of symmetry, and the discrete basis functions are
36
i
(
x
)
=
cos
–
1
(
x
2
+
x
0
i
2
–
(
s
2
)
2
2
x
0
i
x
)
where
s is the diameter of the scanning spot;
x is an x-coordinate measured from the axis of symmetry;
x0i is an x-coordinate for a center of an ith scanning spot;
(x0is2)x(x0is2); and
i(x) is a coverage angle of the ith basis function.
35. The method of claim 34 wherein x0i is specified for M number of equally spaced scanning spots as:
x0ii*(Lse)M,
where
L is the treatment zone length of the section oriented radially across the treatment profile;
e is an extended zone; and
i1, . . . , M.
36. The method of claim 34 wherein fitting the lens function with the basis function comprises solving the following equation for coefficients ai representing treatment depth for the ith scanning spot:
37
f
(
x
)
=
i
=
1
M
a
i
X
i
(
x
)
where
f(x) is the lens function; and
i1, . . . , M.
37. The method of claim 36 wherein the lens function is:
(A) for myopia,
38
f
(
x
)
=
R
1
2
–
x
2
–
(
R
1
(
n
–
1
)
n
–
1
+
R
1
D
)
–
x
2
+
C
or
(B) for hyperopia,
39
f
(
x
)
=
R
1
–
R
1
(
n
–
1
)
n
–
1
+
R
1
D
–
R
1
2
–
x
2
+
(
R
1
(
n
–
1
)
n
–
1
+
R
1
D
)
–
x
2
or
(C) for phototherapeutic keratectomy,
f(x)d;
where
0x(Lshift);
40
C
=
R
1
2
–
s
2
4
+
(
R
1
(
n
–
1
)
n
–
1
+
R
1
D
)
–
s
2
4
;
s is the diameter of the scanning spot;
R1 is the anterior radius of curvature of the cornea in meters;
R2 is the final anterior radius of curvature of the cornea in meters;
n1.377 is the index of refraction of the cornea;
D is the lens power of the scanning spot in diopters;
L is the treatment zone length;
shift is the amount of emphasis shift; and
d is a constant depth.
38. The method of claim 36 further comprising dividing the depth (ai) for the ith scanning spot by a depth per pulse of the laser beam to obtain a number of pulses per an ith treatment ring for the ith scanning spot; and dividing the number of pulses per treatment ring by 2 to obtain an angular spacing between pulses for the ith treatment ring.
39. The method of claim 32 wherein the scanning spots have a fixed spot size and a fixed spot shape.
40. The method of claim 32 wherein at least one of the spot size and spot shape of the scanning spot is variable.
41. A method for fitting a three-dimensional target profile, the method comprising:
providing a two-dimensional basis function including overlapping portions to represent a three-dimensional profile which has symmetry with respect to a two-dimensional section extending along a treatment pattern; and
fitting the three-dimensional target profile with the two-dimensional basis function to obtain a distribution of the overlapping portions.
42. The method of claim 41 wherein the three-dimensional profile has symmetry with respect to a two-dimensional section oriented radially from an axis of symmetry and extending in a generally circular treatment pattern around the axis.
43. The method of claim 42 wherein the overlapping portions are generally circular, and the two-dimensional basis function comprises discrete basis functions each representing a coverage angle of one of the overlapping portions as a function of a distance from the axis of symmetry.
44. The method of claim 41 wherein the three-dimensional profile has symmetry with respect to a two-dimensional section oriented normal across a generally straight treatment pattern.
45. The method of claim 44 wherein the overlapping portions are generally circular, and the two-dimensional basis function comprises discrete basis functions each representing a depth of one of the overlapping portions as a function of a distance from the axis of symmetry.
46. A system for ablating tissue, the system comprising:
a laser for generating a laser beam;
a delivery device for delivering the laser beam to a tissue;
a controller configured to control the laser and the delivery device; and
a memory, coupled to the controller, comprising a computer-readable medium having a computer-readable program embodied therein for directing operation of the system, the computer-readable program including a first set of instructions for generating a treatment table including scanning spot locations and characteristics for ablating the tissue over a treatment region larger in area than the spot size of the laser beam to achieve a desired lens profile for ablating the tissue, a second set of instructions for controlling the laser to generate the laser beam, and a third set of instructions for controlling the delivery device to deliver the laser beam to the tissue according to the treatment table.
47. The system of claim 46 wherein the first set of instructions of the computer-readable program includes:
a first subset of instructions for providing a target function representing the desired lens profile for ablating the tissue by scanning spots of the laser beam on the tissue;
a second subset of instructions for providing a basis function representing a treatment profile produced by the overlapping scanning spots in a treatment pattern; and
a third subset of instructions for fitting the target function with the basis function to obtain the treatment table including the scanning spot locations and characteristics for the overlapping scanning spots of the laser beam.
48. The system of claim 47 wherein the second subset of instructions provide a basis function which is a two-dimensional function representing a two-dimensional section of a three-dimensional treatment profile having symmetry with respect to the two-dimensional section extending along the treatment pattern.
49. The system of claim 47 wherein the first set of instructions of the computer-readable program includes a fourth subset of instructions for refitting the target function with the basis function by varying the spot size of the laser beam to iterate for a best fit.
50. The system of claim 47 wherein the first set of instructions of the computer-readable program includes a fifth subset of instructions for evaluating closeness of the fit and repeating the fitting step if the closeness does not fall within a target closeness.
51. The system of claim 47 wherein the first set of instructions of the computer-readable program includes a sixth subset of instructions for randomizing the scanning spot locations for the treatment table to produce a random scanning order.
52. The system of claim 47 wherein the first set of instructions of the computer-readable program includes a seventh subset of specifying the treatment pattern for scanning with overlapping scanning spots of the laser beam;
53. The system of claim 47 wherein the scanning spot characteristics of a scanning spot at a scanning location include shape, size, and depth of the scanning spot at the scanning location.
54. The system of claim 47 wherein the desired lens profile is selected from the group consisting of an elliptical profile, a hyperopic elliptical profile, a myopic elliptical profile, a circular profile, and a linear profile.
55. The system of claim 47 wherein the desired lens profile is asymmetric.
56. The system of claim 47 wherein the desired lens profile comprises an arbitrary two-dimensional lens profile.
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. A hydraulic control system in a transmission, the transmission having a torque transmitting device, the hydraulic control system comprising:
a source of pressurized hydraulic fluid for providing a pressurized hydraulic fluid;
a first valve in communication with the source of pressurized hydraulic fluid and in communication with the torque transmitting device, the first valve operable to allow communication of the hydraulic fluid from the source of pressurized hydraulic fluid to the torque transmitting device to release the torque transmitting device;
a second valve in communication with the source of pressurized hydraulic fluid and in communication with the torque transmitting device, the second valve moveable between at least a first position and a second position, wherein the second valve prevents the hydraulic fluid from communicating with the torque transmitting device when in the first position and wherein the second valve allows the hydraulic fluid to communicate with the torque transmitting device to engage the torque transmitting device when in the second position; and
an override feature operably associated with at least one of the first valve and the second valve, wherein the override feature is operable to prevent the first valve from communicating the hydraulic fluid to the torque transmitting device when the second valve is in the second position.
2. The hydraulic control system of claim 1 wherein the first valve is moveable between at least a first position and a second position, wherein the first valve allows the hydraulic fluid to communicate with the torque transmitting device to disengage the torque transmitting device when in the first position and wherein the first valve prevents the hydraulic fluid from communicating with the torque transmitting device when in the second position, and
wherein the override feature includes a control device for controlling a position of the first valve and the second valve, wherein when the control device is in a first state the first valve is in the first position and the second valve is in the first position, and when the control device is in a second state the first valve is in the second position and the second valve is in the second position.
3. The hydraulic control system of claim 2 wherein the control device is a three-port variable bleed solenoid.
4. The hydraulic control system of claim 1 wherein the first valve is in communication with the torque transmitting device via the second valve, wherein the second valve allows the hydraulic fluid from the first valve to communicate with the torque transmitting device when in the first position and wherein the second valve prevents the hydraulic fluid from the first valve from communicating with the torque transmitting device when in the second position, and
wherein the override feature includes a control device for controlling a position of the second valve, wherein when the control device is in a first state the second valve is in the first position and when the control device is in a second state the second valve is in the second position.
5. The hydraulic control system of claim 4 wherein the control device is a two-port variable bleed solenoid.
6. The hydraulic control system of claim 1 wherein the first valve is in communication with a release side of the torque transmitting device the second valve is in communication with an apply side of the torque transmitting device.
7. The hydraulic control system of claim 6 wherein the override feature is operable to prevent the first valve from communicating the hydraulic fluid to the release side of the torque transmitting device.
8. A hydraulic control system in a transmission, the transmission having a torque transmitting device, the hydraulic control system comprising:
a source of pressurized hydraulic fluid for providing a pressurized hydraulic fluid;
a compensator valve assembly having an inlet port in communication with the source of pressurized hydraulic fluid and an outlet port in communication with the torque transmitting device, the compensator valve assembly having a compensator valve moveable between at least a first position and a second position, wherein the compensator valve allows fluid communication between the inlet port and the outlet port when in the first position and wherein the compensator valve prevents fluid communication between the inlet port and the outlet port when in the second position;
a regulation valve assembly having an inlet port in communication with the source of pressurized hydraulic fluid and an outlet port in communication with the torque transmitting device, the regulation valve assembly having a regulation valve moveable between at least a first position and a second position, wherein the regulation valve prevents fluid communication between the inlet port and the outlet port when in the first position and wherein the regulation valve allows fluid communication between the inlet port and the outlet port when in the second position; and
a control device operatively associated with the compensator valve assembly and the regulation valve assembly, wherein the control device includes a first state of operation where the compensator valve is in the first position and the regulation valve is in the first position and a second state of operation where the compensator valve is in the second position and the regulation valve is in the second position, and
wherein the torque transmitting device is disengaged when the control device is in the first state of operation, and wherein the torque transmitting device is engaged when the control device is in the second state of operation.
9. The hydraulic control system of claim 8 wherein the control device is a three-port variable bleed solenoid in fluid communication with the source of pressurized hydraulic fluid, the compensator valve, and the regulation valve, and wherein the first state of operation prevents fluid communication between the source of pressurized hydraulic fluid and the compensator valve and the regulation valve, and the second state of operation allows fluid communication between the source of pressurized hydraulic fluid and the compensator valve and the regulation valve.
10. The hydraulic control system of claim 9 wherein the compensator valve is biased to the first position by a first biasing member and the regulation valve is biased to the first position by a second biasing member.
11. The hydraulic control system of claim 8 wherein the compensator valve assembly further includes a feedback port in fluid communication with an end of the compensator valve opposite the first biasing member.
12. The hydraulic control system of claim 11 further comprising a three-way ball check valve having a first port in fluid communication with the outlet port of the compensator valve assembly, a second port in fluid communication with the control device, and a third port in fluid communication with the feedback port of the compensator valve assembly, wherein the second port is closed to the first and third ports when the control device is in the first state and wherein the first port is closed to the second and third ports when the control device is in the second state.
13. The hydraulic control system of claim 8 wherein the compensator valve assembly is in communication with a release side of the torque transmitting device the regulation valve assembly is in communication with an apply side of the torque transmitting device.
14. The hydraulic control system of claim 13 wherein the override feature is operable to prevent the first valve from communicating the hydraulic fluid to the release side of the torque transmitting device.
15. A hydraulic control system in a transmission, the transmission having a torque transmitting device having an apply side and a release side, the hydraulic control system comprising:
a source of pressurized hydraulic fluid for providing a pressurized hydraulic fluid;
a compensator valve assembly having an inlet port in communication with the source of pressurized hydraulic fluid and an outlet port, wherein the compensator valve assembly is operable to regulate a pressure of the hydraulic fluid at the outlet port;
a regulation valve assembly having a first inlet port in communication with the source of pressurized hydraulic fluid, a second inlet port in communication with the outlet port of the compensator valve assembly, a first outlet port in communication with the apply side of the torque transmitting device, and a second outlet port in communication with the release side of the torque transmitting device, the regulation valve assembly having a regulation valve moveable between at least a first position and a second position, wherein the regulation valve prevents fluid communication between the first inlet port and the first outlet port and allows fluid communication between the second inlet port and the second outlet port when in the first position and wherein the regulation valve allows fluid communication between the first inlet port and the first outlet port and prevents fluid communication between the second inlet port and the second outlet port when in the second position; and
a control device operatively associated with the regulation valve assembly, wherein the control device includes a first state of operation where the regulation valve is in the first position and a second state of operation where the regulation valve is in the second position, and
wherein the torque transmitting device is disengaged when the control device is in the first state of operation, and wherein the torque transmitting device is engaged when the control device is in the second state of operation.
16. The hydraulic control system of claim 15 wherein the control device is a two-port variable bleed solenoid in fluid communication with the source of pressurized hydraulic fluid and the regulation valve, and wherein the first state of operation prevents fluid communication between the source of pressurized hydraulic fluid and the regulation valve, and the second state of operation allows fluid communication between the source of pressurized hydraulic fluid and the regulation valve.
17. The hydraulic control system of claim 15 wherein the regulation valve is biased to the first position by a biasing member.
18. The hydraulic control system of claim 17 wherein the regulation valve assembly further includes a feedback port in fluid communication with the first outlet port and with an end of the compensator valve opposite the first biasing member.