1. A power supply unit, comprising:
a power source generating a radio frequency power;
an impedance matching box connected to the power source and matching an internal impedance of the power source and a load impedance;
a first feed line connected to the impedance matching box;
a radio frequency distributing means connected to the first feed line; and
a plasma electrode connected to the radio frequency distributing means, the radio frequency distributing means supplying the radio frequency power to a plurality of points of the plasma electrode.
2. The power supply unit according to claim 1, wherein the radio frequency power is symmetrically supplied to the plurality of points of the plasma electrode.
3. The power supply unit according to claim 1, wherein the radio frequency distributing means comprises:
a distributing part having a plate shape, the first feed line being connected to a central portion of the distributing part; and
a plurality of second feed lines connecting the distributing part and the plasma electrode.
4. The power supply unit according to claim 3, wherein the plurality of second feed lines have a cylindrical shape.
5. The power supply unit according to claim 3, wherein the plurality of second feed lines have a plate shape.
6. The power supply unit according to claim 5, wherein the plurality of second feed lines include first and second plates facing each other and connecting two edge sides of the distributing part and the plasma electrode.
7. The power supply unit according to claim 5, wherein the plurality of second feed lines include first, second, third and fourth plates connecting four edge sides of the distributing part and the plasma electrode, the first and second plates facing each other and the third and fourth plates facing each other.
8. The power supply unit according to claim 1, wherein the radio frequency distributing means comprises:
a distributing part having a plurality of radial branches, the first feed line being connected to a central portion of the distributing part; and
a plurality of second feed lines connecting the distributing part and the plasma electrode.
9. The power supply unit according to claim 8, wherein the distributing part is parallel to the plasma electrode.
10. The power supply unit according to claim 8, wherein the distributing part constitutes a plurality of electric paths for transmitting the radio frequency power to the plasma electrode, and the plurality of electric paths have a substantially equal length to each other.
11. The power supply unit according to claim 1, wherein the radio frequency distributing means comprises:
a first distributing part having a plurality of radial branches, the first feed line being connected to a central portion of the first distributing part;
a second distributing part extending from the first distributing part; and
a plurality of second feed lines connecting the first distributing part and the plasma electrode and connecting the second distributing part and the plasma electrode.
12. The power supply unit according to claim 11, wherein the first and second distributing parts are parallel to the plasma electrode.
13. The power supply unit according to claim 11, wherein the second distributing part has a plurality of branches, each branch extending from each radial branch.
14. The power supply unit according to claim 11, wherein the first and second distributing parts constitute a plurality of electric paths for transmitting the radio frequency power to the plasma electrode, and the plurality of electric paths have a substantially equal length to each other.
15. A plasma apparatus, comprising:
a process chamber treating a substrate;
a power source outside the process chamber and generating a radio frequency power;
an impedance matching box connected to the power source and matching an internal impedance of the power source and a load impedance;
a first feed line connected to the impedance matching box;
a distributing part over the process chamber, the first feed line being connected to a central portion of the distributing part;
a plasma electrode in the process chamber;
a plurality of second feed lines connecting the distributing part and the plasma electrode, the distributing part and the plasma electrode supplying the radio frequency power to a plurality of points of the plasma electrode; and
a susceptor facing the plasma electrode and having the substrate thereon.
16. The plasma apparatus according to claim 15, wherein the plurality of second feed lines connect the distributing part and the plasma electrode through the process chamber.
17. The plasma apparatus according to claim 15, further comprising a housing surrounding the distributing part.
18. The plasma apparatus according to claim 15, wherein the distributing part has a plate shape and the first feed line is connected to a central portion of the distributing part.
19. The plasma apparatus according to claim 15, wherein the distributing part has a plurality of radial branches and the first feed line is connected to a central portion of the distributing part.
20. The plasma apparatus according to claim 15, wherein the distributing part comprises:
a first sub-distributing part having a plurality of radial branches, the first feed line being connected to a central portion of the first distributing part; and
a second sub-distributing part extending from the first distributing part,
wherein the plurality of second feed lines connect the first sub-distributing part and the plasma electrode and connect the second sub-distributing part and the plasma electrode.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
What we claim is:
1. An imaging system comprising an image-formation lens system and a means located on the image side thereof for defining an image pickup area, wherein:
said image-formation lens system is a zoom lens system comprising at least three lens groups including a lens group of positive power and a lens group of negative power, wherein zooming is carried out by varying a spacing between adjacent lens groups, and
said zoom lens system comprises a total of up to 8 lenses, and satisfies the following conditions:
0.07<gIH<0.23(1) 1.8<TeleFnoWideFno<3(2) 8%<DTLw<8%(3)
where g is a difference between rear focal positions at d- and g-lines of said zoom lens system at a telephoto end, IH is a maximum image height at an image plane, WideFno and TeleFno are F-numbers at d-line of said zoom lens system at wide-angle end and telephoto end, respectively, and DTLw is an amount of d-line distortion at an angle of view of 28.0 at the wide-angle end.
2. The imaging system according to claim 1, wherein said maximum image height IH at the image plane satisfies the following condition:
20 mm<IH<25 mm(8)
3. The imaging system according to claim 1 or 2, wherein at least one of said lens groups having negative power consists of a plurality of negative lenses whose power turns negative on an optical axis, wherein at least one of said plurality of negative lenses is an aspheric lens whose power turns from negative to positive farther off a center thereof, and at least one negative lens included in said plurality of negative lenses and different from said aspheric lens maintains negative power all the way from a center to a periphery thereof.
4. The imaging system according to claim 3, wherein said aspheric lens satisfies following condition:
10<faspfN<100(4)
where fasp is a focal length of the aspheric lens on the optical axis, and fN is the focal length on the optical axis of the lens group of negative power including the aspheric lens.
5. The imaging system according to claim 1, wherein said image-formation lens system is a three-group zoom lens comprising, in order from an object side thereof, a lens group of positive power, a lens group of positive power and a lens group of negative power wherein zooming is performed by varying the spacing between adjacent lens groups, and satisfies the following condition:
0.55<Ltft<0.715(5)
where Lt is a real distance at the telephoto end of the image-formation lens system from a plane located nearest the object side to the image plane, and ft is the composite focal length at the telephoto end of the image-formation lens system.
6. An image-formation lens system comprising a plurality of lenses with aspheric lenses, wherein:
any one of said aspheric lenses has an aspheric surface on an entrance side or an exit side thereof, and satisfies the following conditions:
0.4>(ZmaxZhalf)Ymax>0.18(6) 0.05>ZhalfYmax0(7)
where Ymax is a maximum value of a distance of said aspheric lens surface from an optical axis, Zmax is an absolute value of a distance from a plane vertical to the optical axis including a lens surface apex at Ymax, and Zhalf is an absolute value of a distance from a plane vertical to the optical axis including a lens surface apex at a half distance of said maximum value Ymax, provided that the lens surface refers to an entire area wherein a surface shape inclusive of an effective diameter exists continuously, indicative of a boundary between that area and an area where the surface shape becomes discontinuous.
7. The image-formation lens system according to claim 6, which satisfies either one of the following conditions:
0.4>(ZmaxZhalf)Ymax>0.20(6) 0.03>ZhalfYmax0(7)
8. An imaging system, which comprises an image-formation lens system as recited in claim 6 and a means located on an image side thereof for defining an image pickup area, wherein:
said image-formation lens system comprises a plurality of lens groups including a lens group of positive power and a lens group of negative power, wherein zooming is performed by varying a spacing between adjacent lens groups, and
said aspheric lens is located within a lens group wherein a chief ray having the largest image height at an image plane is farthest off an optical axis in a zooming zone.
9. The imaging system according to claim 8, wherein said aspheric lens is located in a lens group nearest to the image side, with satisfaction of the following condition (9):
8.5>ftIH>5.8(9)
where ft is a composite focal length of the image-formation lens system at the telephoto end, and IH is a maximum image height at the image plane.
10. The image-formation lens system according to claim 6, which comprises an aperture stop, wherein said aspheric lens is such that a normal to said aspheric surface at a position spaced away from an optical axis on said aspheric surface along a lens surface by 70% of Ymax is inclined toward the optical axis side in a direction in which said aperture stop is located, and a lens having an effective diameter larger than that of said aspheric lens is located on a side of said aspheric lens opposite to said aperture stop and adjacent to said aspheric lens on the optical axis with only an air gap therebetween.
11. The image-formation lens system according to claim 10, wherein the lens located adjacent to said aspheric lens is a meniscus lens having a concave surface on an aperture stop side, wherein said concave surface and said aspheric surface are opposite to each other with an air gap therebetween and said aspheric surface and said concave surface are close to each other around peripheral positions thereof.
12. The image-formation lens system according to claim 10 or 11, wherein said aspheric lens has a meniscus shape concave with respect to said aperture stop.
13. The image-formation lens system according to claim 12, wherein the lens adjacent to the aspheric lens is configured in a meniscus form having a concave surface on the aperture stop side and negative power.
14. The imaging system according to claim 8, wherein:
a lens group wherein said chief ray is farthest off the optical axis in a zooming zone is a lens group located nearest to the image side of said zoom lens system,
said lens group located adjacent to the image side has negative power and consists of a plurality of negative lenses whose power turns negative on the optical axis,
said aspheric lens is any one of said plurality of negative lenses, wherein power turns from negative to positive farther off a center thereof, and
at least one of said plurality of negative lenses, different from said aspheric lens, is a negative lens that maintains negative power all the way from a center to a periphery thereof.
15. The imaging system according to claim 8, wherein:
a lens group wherein said chief ray is farthest off the optical axis in a zooming zone is a lens group located nearest to the object side of said zoom lens system,
said lens group located nearest to the object side is a lens group having negative power and comprising a plurality of lenses, each having power turning negative on the optical axis,
a lens having an aspheric surface is provided somewhere other than the side nearest to the object side, wherein said aspheric lens is any one of said plurality of lenses, which has gradually increasing positive power farther off a center thereof, and
at least one of said plurality of lenses, different from said aspheric lens, is a negative lens that maintains negative power all the way from a center to a periphery thereof.
16. The imaging system according to claim 8, wherein said zoom lens comprises up to 8 lenses in all.
17. An image-formation lens system, which comprises, in order from an object side thereof, a first lens group having positive power, a second lens group having positive power and a third lens group having negative power, wherein zooming from a wide-angle end to a telephoto end of the image-formation lens system is performed by allowing a spacing between the first lens group and the second lens group to become wide and a spacing between the second lens group and the third lens group to become narrow, and the third lens group consists of two negative lenses having negative power on an optical axis and satisfies the following conditions (10) and (5):
0.8<d1Dair<2.0(10) 0.55<Ltft<0.715(5)
where d1 is a thickness on the optical axis of an object side-negative lens in the third lens group, Dair is an air gap between the two negative lenses in the third lens group, Lt is a real distance of the image-formation lens system from a surface located nearest to the object side to an image plane as measured at the telephoto end, and ft is a composite focal length of the image-formation lens system at the telephoto end.
18. The imaging system according to any one of claims 1, 2, 5 and 8, wherein:
said image-formation lens system comprises, in order from an object side thereof, a first lens group having positive power, a second lens group having positive power and a third lens group having negative power, wherein zooming from a wide-angle end to a telephoto end thereof is performed with a zoom ratio of at least 3.3 by allowing a spacing between the first lens group and the second lens group to become wide and a spacing between the second lens group and the third lens group to become narrow.
19. The image-formation lens system according to any one of claims 6, 7 and 10, which comprises, in order from an object side thereof, a first lens group having positive power, a second lens group having positive power and a third lens group having negative power, wherein zooming from a wide-angle end to a telephoto end thereof is performed with a zoom ratio of at least 3.3 by allowing a spacing between the first lens group and the second lens group to become wide and a spacing between the second lens group and the third lens group to become narrow.
20. The imaging system according to claim 3, wherein said negative power lens group including an aspheric lens is a lens group located nearest to the image side thereof, and consists of two negative lenses on an optical axis.
21. The image-formation lens system according to any one of claims 6, 7 and 10, which comprises at least three lens groups including a lens group having positive power and a lens group having negative power wherein a spacing between adjacent lenses is varied for zooming, wherein:
at least one lens group having negative power includes said aspheric lens, is located nearest to the image side thereof, and consists of two negative lenses on an optical axis.
22. The imaging system according to claim 20, wherein one of said two negative lenses is a plastic aspheric lens having a d-line refracting index of up to 1.6 and the other is a glass lens having a d-line refractive index of at least 1.6.
23. The image-formation lens system according to claim 21, wherein one of said two negative lenses is a plastic aspheric lens having a d-line refracting index of up to 1.6 and the other is a glass lens having a d-line refractive index of at least 1.6.
24. The imaging system according to claim 5, wherein said second lens group is configured at a surface located nearest to the object side in such a way as to be concave on the object side, and comprises a doublet that consists of a positive lens and a negative lens and satisfies the following conditions:
1.85>nd>1.7(11) 60>d>40(12)
where nd and d are a d-line refractive index and an Abbe number of the negative lens in the doublet, respectively.
25. The imaging system according to claim 18, wherein said second lens group is configured at a surface located nearest to the object side in such a way as to be concave on the object side, and comprises a doublet that consists of a positive lens and a negative lens and satisfies the following conditions:
1.85>nd>1.7(11) 60>d>40(12)
where nd and d are a d-line refractive index and an Abbe number of the negative lens in the doublet, respectively.
26. The image-formation lens system according to claim 17, wherein said second lens group is configured at a surface located nearest to the object side in such a way as to be concave on the object side, and comprises a doublet that consists of a positive lens and a negative lens and satisfies the following conditions:
1.85>nd>1.7(11) 60>d>40(12)
where nd and d are a d-line refractive index and an Abbe number of the negative lens in the doublet, respectively.
27. The image-formation lens system according to claim 19, wherein said second lens group is configured at a surface located nearest to the object side in such a way as to be concave on the object side, and comprises a doublet that consists of a positive lens and a negative lens and satisfies the following conditions:
1.85>nd>1.7(11) 60>d>40(12)
where nd and d are a d-line refractive index and an Abbe number of the negative lens in the doublet, respectively.
28. The imaging system according to claim 5 or 24, wherein in said first lens group or said third lens group there is located a flare stop that is similar in shape to the image plane and differs in length in long and short side directions, thereby cutting off at least a part of harmful light beams in the long and short side directions.
29. The imaging system according to claim 18, wherein in said first lens group or said third lens group there is located a flare stop that is similar in shape to the image plane and differs in length in long and short side directions, thereby cutting off at least a part of harmful light beams in the long and short side directions.
30. The image-formation lens system according to claim 17, which is a three-group zoom lens wherein said first lens group, said second lens group and said third lens group move in such a way as to vary a spacing between adjacent lens groups.