1. A manually actuatable roll-up window shade for a motor vehicle comprising:
a rotatably supported wind-up shaft having first and second ends;
a shade element having a first edge fixed to the wind-up shaft;
a pull rod connected to a second end of the shade element remote from the wind-up shaft;
two guide rails for guiding the pull rod that extend on opposite sides of the shade element when the shade element is in an extended position;
two push elements each of which is guided by a respective one of the guide rails, each push element carrying teeth that interact with the pull rod;
two drive gears arranged at the first and second ends of the wind-up shaft, each drive gear being allocated to a respective one of the push elements, wherein the push elements are operatively arranged between the drive wheels and the pull rod; and
a tensioning mechanism for maintaining tension in the shade element.
2. The window shade according to claim 1, wherein the tensioning mechanism includes spring mechanisms.
3. The window shade according to claim 2, wherein a spring mechanism is operatively arranged between the wind-up shaft and each of the two drive gears.
4. The window shade according to claim 2, wherein each drive gear is coupled with the wind-up shaft via a separate spring mechanism.
5. The window shade according to claim 2, wherein each spring mechanism comprises a spiral spring.
6. The window shade according to claim 1, wherein the two drive gears sit on a connection shaft.
7. The window shade according to claim 6, wherein the tensioning mechanism includes gear elements that operatively connect the connection shaft to the wind-up shaft.
8. The window shade according to claim 6, wherein the tensioning mechanism includes gear elements that operatively connect the connection shaft to the wind-up shaft and the tensioning mechanism further includes spring elements.
9. The window shade according to claim 7, wherein each drive gear is coupled with the connection shaft via a spring element.
10. The window shade according to claim 7, wherein the drive gears sit locked in rotation on the connection shaft.
11. The window shade according to claim 7, wherein the gear elements comprise two gears that are engaged with each other, one gear being coupled with the wind-up shaft and the gear being coupled with the connection shaft.
12. The window shade according to claim 11, wherein one of the two gears is coupled with its respective shaft via a spring element.
13. The window shade according to claim 7, wherein the gear elements include a cable gear.
14. The window shade according to claim 13, wherein the cable gear comprises a cylindrical pulley and a cable worm.
15. The window shade according to claim 1, wherein the pull rod is configured so such that its length is selectively adjustable.
16. The window shade according to claim 1, wherein a first end of each of the guide rails is in the vicinity of the wind-up shaft.
17. The window shade according to claim 1, wherein the guide rails extend parallel to each other.
18. The window shade according to claim 1, wherein each guide rail includes a guide groove.
19. The window shade according to claim 18, wherein the cross-sectional configuration of the guide groove includes a groove chamber and a groove slot, wherein a diameter of the groove chamber is greater than an open width of the slot such that an undercut guide groove is produced.
20. The window shade according to claim 19, wherein each push element is guided in a buckle free manner in the respective groove chamber.
21. The window shade according to claim 1, wherein each push element has teeth all around.
22. The window shade according to claim 1, wherein each drive gear is a spur gear.
23. The window shade according to claim 1, wherein each push element has an associated engagement mechanism for keeping the respective push element engaged with its associated drive gear.
24. The window shade according to claim 1, wherein a separate gear housing is provided for each drive gear.
25. The window shade according to claim 1, wherein each push element includes a separate storage tube for holding a slack section of the push element when the window shade is a retracted position.
26. The window shade according to claim 25, wherein each storage tube comprises a flexible material.
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. An imaging arrangement comprising: an imaging lens assembly including at least one lens having a certain affective aperture, and at least one optical element associated with said at least one lens and configured to provide an extended depth of focus of the imaging arrangement, said optical element being configured as a phase-affecting, non-diffractive optical element defining a spatially low frequency phase transition, said optical element together with its associated lens defining a predetermined pattern formed by spaced-apart optically transparent features of different optical properties, position of at least one phase transition region of the optical element within the lens plane being determined by at least a dimension of said affective aperture.
2. The arrangement of claim 1, wherein said lens assembly includes the single lens associated with the single optical element.
3. The arrangement of claim 1, comprising the lens assembly including an array of lenses, and an array of the optical elements, each optical element being associated with the corresponding one of the lenses.
4. The arrangement of claim 1, wherein said optical element is configured as a phase-only element.
5. The arrangement of claim 4, wherein said optical element is configured as a binary mask.
6. The arrangement of claim 1, wherein said optical element is a configured as a phase and amplitude affecting element.
7. The arrangement of claim 1, wherein the optical element is configured to maximize a defocused optical transfer function (OTF) of the imaging arrangement by providing the out of focus OTF as much as possible away from zero.
8. The arrangement of claim 7, wherein the optical element is configured to produce proper phase interference relation between light portions passing through different regions of the imaging arrangement corresponding to the different features of the pattern to thereby reduce a quadratic phase factor resulting from light getting out of focus of the imaging lens.
9. The arrangement of claim 1, wherein said at least one transition region is configured as a pi-phase transition for a certain wavelength for which the optical element is designed.
10. The arrangement of claim 1, wherein said at least one transition region is configured as about pi2 phase transition for a certain wavelength range for which the optical element is designed.
11. The arrangement of claim 1, wherein the position of said at least one transition region with respect to the imaging lens is determined by optical power of the imaging lens.
12. The arrangement of claim 7, wherein the position for N transition regions of the optical element within the imaging lens plane maximizing the OTF is determined as:
max
a
n
\u2062
{
min
\u2062
{
D
\u223c
\u2061
(
v
)
\u2062
\u2211
n
=
1
N
\u2062
\u2003
\u2062
a
n
\u2062
rect
\u2061
(
v
–
n
\u2062
\u2003
\u2062
\u0394
\u2062
\u2003
\u2062
v
\u0394
\u2062
\u2003
\u2062
v
)
\u2297
D
\u223c
\u2061
(
v
)
\u2062
\u2211
n
=
1
N
\u2062
\u2003
\u2062
a
n
\u2062
rect
\u2061
(
v
–
n
\u2062
\u2003
\u2062
\u0394
\u2062
\u2003
\u2062
v
\u0394
\u2062
\u2003
\u2062
v
)
}
}
values for an providing maximum for minima of an expression for auto correlation of a Coherent Transfer Function (CTF) of the imaging lens, where an equals either 1 or \u22121, {tilde over (D)}(\u03bd) being the CTF of the imaging lens corresponding to out of focus position of an object being imaged and being determined as
D
\u223c
\u2061
(
v
)
=
exp
\u2061
(
\u2148
\u2062
\u2003
\u2062
4
\u2062
\u03a8
\u2062
\u2003
\u2062
v
2
\u2062
\u2003
D
2
)
,
wherein D is the affective aperture dimension, \u03bd is a coordinate of the affective aperture in the CTF plane, and \u03c8 is a phase factor representing a degree of getting out of focus.
13. The arrangement of claim 1, wherein said at least one transition region has a sub-pattern formed by an array of variable phase transition sub-regions.
14. The arrangement of claim 9, wherein said at least one pi-phase transition region has a sub-pattern formed by an array of variable pi-phase transition sub-regions.
15. The arrangement of claim 1, wherein the optical element is configured as at least one annular transition region.
16. The arrangement of claim 1, wherein the optical element is configured as a grid.
17. The arrangement of claim 1, wherein said optical element is spaced-apart from the imaging lens along an optical axis of the imaging lens.
18. The arrangement of claim 1, wherein said optical element is attached to the imaging lens.
19. The arrangement of claim 1, wherein said optical element is made integral with the imaging lens.
20. The arrangement of claim 1, wherein said optical element is configured as a mask formed by an array of said transition regions arranged in a spaced-apart relationship being spaced by the optically transparent regions of the imaging lens within the imaging lens plane.
21. The arrangement of claim 1, comprising two phase affecting optical elements located in spaced-apart substantially parallel planes at opposite sides, respectively, of said at least one lens.
22. The arrangement of claim 19, wherein said at least one transition region is formed as a surface relief on the imaging lens surface, defining a lens thickness within said at least one region different from that within other regions of the lens.
23. The arrangement of claim 19, wherein said at least one transition region is formed by a material having refractive index different from that of the imaging lens material.
24. The arrangement of claim 19, wherein said optical element is configured as a mask formed by an array of the phase transition regions formed by a material having refractive index different from that of the imaging lens material.
25. The arrangement of claim 7, wherein the optical element is configured to maximize the OTF by reducing high-frequency cancellation at large shifts of a Coherent Transfer Function (CTF) of the imaging lens.
26. The arrangement of claim 7, wherein the optical element is configured to maximize the OTF by reducing sensitivity of the lens arrangement to shifts of a Coherent Transfer Function (CTF) of the imaging lens while getting out of focus.
27. The arrangement of claim 1, wherein the optical element is configured to produce periodic replication of a lateral phase shape of a light field propagating through the imaging lens.
28. The arrangement of claim 1, wherein the optical element is configured in accordance with a free space propagation of the optical element function for a distance between the optical element and the imaging lens plane.
29. The arrangement of claim 1, wherein the optical element is configured to produce non-periodic replication of a lateral phase shape of a light field propagating through the imaging lens.
30. The arrangement of claim 1, wherein the optical element is configured to produce random replication of a lateral phase shape of a light field propagating through the imaging lens.
31. The arrangement of claim 1, for use in patients’ spectacles.
32. An optical element for use with an imaging lens in the imaging arrangement of claim 1 for extending depth of focus of imaging, the optical element being configured as a phase-affecting, non-diffractive optical element defining a predetermined pattern of spatially low frequency phase transitions, said pattern being defined by an affective aperture of the given imaging lens.
33. A system for creating an image of an object on a detector plane, the system comprising the imaging lens arrangement of claim 1.
34. The system of claim 32, wherein said object is a screen of a display device to be imaged on the eye retina constituting the detector plane.
35. A display device carrying the imaging arrangement of claim 1.
36. A method for providing a certain extended depth of focus of an imaging system, the method comprising applying an aperture coding to an imaging lens having a certain effective aperture, by applying to the imaging lens at least one phase-affecting non-diffractive optical element configured to define a spatially low frequency phase transition arrangement and thereby provide a predetermined pattern of spaced-apart substantially optically transparent features of different optical properties within the imaging lens plane, thereby producing phase interference relation between light portions passing through different regions of the lens arrangement corresponding to the different features of the pattern so as to reduce a quadratic phase factor resulting from light getting out of focus of the imaging lens and maximize a defocused optical transfer function (OTF) of the imaging lens arrangement.
37. A method for designing the optical element of claim 32, said designing comprising selecting N positions for the phase transitions within the imaging lens effective aperture as those providing maximal contrast of an Optical Transfer Function (OTF) of the imaging system under a set of out of focus locations, thereby providing the out of focus OTF as much as possible away from zero.
38. The method of claim 37, wherein the positions for said N transition regions of the optical element within the imaging lens plane maximizing the OTF are determined as:
max
a
n
\u2062
{
min
\u2062
{
D
\u223c
\u2061
(
v
)
\u2062
\u2211
n
=
1
N
\u2062
\u2003
\u2062
a
n
\u2062
rect
\u2061
(
v
–
n
\u2062
\u2003
\u2062
\u0394
\u2062
\u2003
\u2062
v
\u0394
\u2062
\u2003
\u2062
v
)
\u2297
D
\u223c
\u2061
(
v
)
\u2062
\u2211
n
=
1
N
\u2062
\u2003
\u2062
a
n
\u2062
rect
\u2061
(
v
–
n
\u2062
\u2003
\u2062
\u0394
\u2062
\u2003
\u2062
v
\u0394
\u2062
\u2003
\u2062
v
)
}
}
values for an providing maximum for minima of an expression for auto correlation of a Coherent Transfer Function (CTF) of the imaging lens, where an equals either 1 or \u22121, {tilde over (D)}(\u03bd) being the CTF of the imaging lens corresponding to out of focus position of an object being imaged and being determined as
D
\u223c
\u2061
(
v
)
=
exp
\u2061
(
\u2148
\u2062
\u2003
\u2062
4
\u2062
\u03a8
\u2062
\u2003
\u2062
v
2
\u2062
\u2003
D
2
)
,
wherein D is the affective aperture dimension, \u03bd is a coordinate of the affective aperture in the CTF plane, and, and \u03c8 is a phase factor representing a degree of getting out of focus.
39. The method of claim 37, comprising fabricating a mask formed by an arrangement of the N transitions spaced-apart from each other in accordance with said selected N positions.
40. The method of claim 39, comprising attaching said mask to the surface of the imaging lens aperture.
41. The method of claim 37, comprising patterning the surface of the imaging lens aperture to form a mask of the N transitions spaced-apart from each other in accordance with said selected N positions.
42. The method of claim 40, comprising providing said surface substantially flat to thereby allow insertion of the patterned imaging lens into a patient’s eye.
43. The method of claim 37, wherein the designing of the optical element comprises producing a phase interference relation between light portions passing through said N regions and spaces between them to thereby reduce a quadratic phase factor resulting from light getting out of focus of the imaging lens and maximize a defocused optical transfer function (OTF) of an arrangement formed by the imaging lens and the optical element.
44. The method of claim 41, wherein said patterning comprises applying material removal to the lens regions within said N positions, and filling said regions, from which the lens material has been removed, by a material of a refraction index different from that of the lens, so as to provide a refraction index difference such that the outer region of the patterned lens is flat and proper equalization between the different material regions is provided to produce a phase interference relation between light portions passing through different material regions to thereby reduce a quadratic phase factor resulting from light getting out of focus of the imaging lens and maximize a defocused optical transfer function (OTF) of the patterned imaging lens.
45. The method of claim 41, wherein said patterning comprises applying diffusion or photo polymerization to the lens regions within said N positions, so as to provide a refraction index difference between said N regions and spaces between them such that the outer region of the patterned lens is flat and proper equalization between the different material regions is provided to produce a phase interference relation between light portions passing through different material regions to thereby reduce a quadratic phase factor resulting from light getting out of focus of the imaging lens and maximize a defocused optical transfer function (OTF) of the patterned imaging lens.
46. The method of claim 37, comprising implanting in the patient’s eye tissue, within said selected N positions, an artificial tissue having a refraction index different from that of the eye tissue.