1. A pressure sensor, comprising:
a platform;
at least one separating membrane, which, with the platform, encloses a pressure chamber, said platform defining a hydraulic path which communicates with said pressure chamber, and defining a canal and a platform blind hole in a surface of said platform, which extends from the end of the platform blind hole, said canal communicating with said hydraulic path, wherein the diameter of said canal is smaller than the diameter of said platform blind hole, so that a first abutment surface is formed between said platform blind hole and said canal;
a sealing element insertable into said platform blind hole, said sealing element having a second abutment surface for supporting said sealing element on said first abutment surface, and additionally having a radially flexible, lateral surface; and
an expander, which can be brought into engagement with said sealing element, in order to expand the lateral surface of said sealing element radially.
2. The pressure sensor as claimed in claim 1, wherein:
said lateral surface of the sealing element is radially elastic and the outer diameter of said lateral surface in the equilibrium position is less than the inner diameter of said platform blind hole.
3. The pressure sensor as claimed in claim 1, wherein:
said sealing element has on its rear side away from said second abutment surface a blind hole, into which said expander can be inserted.
4. The pressure sensor as claimed in claim 3, wherein:
said outer diameter of said expander is greater than the inner diameter of said sealing element blind hole, so that the lateral surface of said sealing element is pressed against the lateral surface of said platform blind hole by insertion of said expander.
5. The pressure sensor as claimed in claim 1, wherein:
said expander has at least one tapering end section.
6. The pressure sensor as claimed in claim 1, wherein:
said platform blind hole has at least one recess on its lateral surface and said sealing element has at least one locking means, which can be brought into engagement with said at least one recess by means of said expander.
7. The pressure sensor as claimed in claim 1, wherein:
said platform comprises a ceramic material.
8. The pressure sensor as claimed in claim 1, wherein:
said second abutment surface has a shape which is complementary to that of said first abutment surface.
9. The pressure sensor as claimed in claim 1, wherein:
said pressure sensor is one of: an absolute pressure sensor, a relative pressure sensor or a differential pressure sensor.
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 zoom lens, comprising in order from an object side to an image side:
a first lens unit having a positive refractive power that does not move for zooming;
a second lens unit having a negative refractive power that moves during zooming;
a magnification-varying system including two or more lens units, which includes a third lens unit having a positive refractive power that moves during zooming; and
a fourth lens unit having a positive refractive power that does not move for zooming,
wherein the fourth lens unit includes:
a first lens subunit having a negative refractive power;
a second lens subunit having a negative refractive power that moves in a direction having a component perpendicular to an optical axis so as to displace an image in a direction perpendicular to the optical axis; and
a third lens subunit having a positive refractive power; and
the following conditional expression is satisfied:
1.2<f41f42<3.5,
where f41 represents a focal length of the first lens subunit, and f42 represents a focal length of the second lens subunit.
2. A zoom lens according to claim 1, wherein the second lens subunit is composed of a single positive lens and a single negative lens.
3. A zoom lens according to claim 1, wherein:
the second lens subunit is composed of two negative lenses and a single positive lens; and
the following conditional expression is satisfied:
3.0 (gcm3)<dave<5.1 (gcm3),
where dave (gcm3) represents an average value of specific gravities of materials of the two negative lenses.
4. A zoom lens according to claim 1, wherein:
the first lens subunit is composed of a single negative lens and a single positive lens; and
the following conditional expression is satisfied:
10<|\u03bd41p\u2212\u03bd41n|25,
where \u03bdd41p represents an Abbe number of a material of the positive lens, and \u03bdd41n represents an Abbe number of a material of the negative lens.
5. A zoom lens according to claim 1, wherein the following conditional expressions are satisfied:
10<|\u03bdd42p\u2212\u03bdd42n|<25; and
10<|\u03bdd43p\u2212\u03bdd43n|<25,
where \u03bdd42p represents an average Abbe number of materials of positive lenses among lenses constituting the second lens subunit, \u03bdd42n represents an average Abbe number of materials of negative lenses among the lenses constituting the forth lens subunit, \u03bdd43p represents an average Abbe number of materials of positive lenses among lenses constituting the third lens subunit, and \u03bdd43n represents an average Abbe number of materials of negative lenses among the lenses constituting the third lens subunit.
6. A zoom lens according to claim 1, wherein:
during zooming from a wide-angle side to a telephoto side, the second lens unit moves on the optical axis from the object side to the image side, whereas the third lens unit moves on the optical axis from the image side to the object side and passes through a zoom position having an imaging magnification of \u22121 during the movement; and
the following conditional expressions are satisfied:
10<Z2maxZ2min; and
0.13<Z2max(Z2min\xd7Z),
where Z2max and Z2min represent a maximum value and a minimum value of lateral magnification of the second lens unit, respectively, and Z represents a zoom ratio of a zoom lens of an entire system.
7. A zoom lens according to claim 1, wherein the following conditional expression is satisfied:
0.5<|\u03b242|<15,
where \u03b242 represents imaging magnification of the second lens subunit.
8. An image pickup apparatus, comprising:
the zoom lens according to claim 1; and
an image pickup element which receives an image formed by the zoom lens.
9. An image pickup apparatus according to claim 8, wherein:
the following conditional expression is satisfied:
3<SKIm<6,
where SK represents an equivalent length in air of a distance between an image plane and a lens surface which is disposed on the most image plane side among lenses constituting the fourth lens unit, and Im represents an image size of the image pickup element.
10. An image pickup apparatus according to claim 8, wherein:
the following conditional expression is satisfied:
0.04 (radmm)<|\u03b1\u2032IS\u2212\u03b1IS|Im<0.14 (radmm),
where \u03b1IS (rad) represents an incident conversion angle of inclination of a beam to a lens surface which is disposed on the most object side among lenses constituting the second lens subunit, \u03b1\u2032IS (rad) represents an exit converted inclination angle of a beam from a lens surface which is disposed on the most image side among the lenses constituting the second lens subunit, and Im represents an image circle of the image pickup element.