1. A temperature measuring apparatus for measuring a temperature of an object having a first main surface and a second main surface which is opposite to the first main surface, the temperature measuring apparatus comprising:
a data input unit which inputs a spectrum of interference light that is obtained when measuring light is irradiated to the first main surface of the object and the measuring light reflected by the first main surface and the measuring light reflected by the second main surface interfere with each other;
a peak interval calculation unit which calculates a peak interval of the spectrum;
an optical path length calculation unit which calculates a length of an optical path from the first main surface to the second main surface, based on the peak interval; and
a temperature calculation unit which calculates the temperature of the object based on the optical path length.
2. The temperature measuring apparatus of claim 1, wherein the peak interval calculated by the peak interval calculation unit is an interval between adjacent peaks.
3. The temperature measuring apparatus of claim 1, wherein the peak interval calculation unit calculates the optical path length based on an average value of a plurality of the peak intervals.
4. The temperature measuring apparatus of claim 1, wherein the temperature calculation unit calculates the temperature of the object based on a correlation obtained in advance between temperatures of the object and the optical path length.
5. The temperature measuring apparatus of claim 1, wherein the optical path length calculation unit calculates the optical path length from the first main surface to the second main surface based on a correlation between peak intervals and optical path lengths.
6. The temperature measuring apparatus of claim 1, wherein the object is formed of silicon, quartz, or sapphire.
7. A substrate processing apparatus for performing a predetermined process on a substrate having a first main surface and a second main surface which is opposite to the first main surface and measuring a temperature of the substrate, the substrate processing apparatus comprising:
a processing chamber which is configured to be vacuum exhausted and to accommodate the substrate;
a light source which generates measuring light having a wavelength transmittable through the substrate;
a spectroscope which measures spectrums depending on a wavelength or a frequency;
an optical transfer mechanism which is connected to the light source and the spectroscope to emit the measuring light from the light source to the first main surface of the substrate and emit lights reflected from the first main surface and the second main surface to the spectroscope;
a data input unit which inputs a spectrum of interference light obtained by interference between the lights reflected from the first main surface and the second main surface, wherein the spectrum is measured by the spectroscope;
a peak interval calculation unit which calculates a peak interval in the spectrum;
an optical path length calculation unit which calculates a length of an optical path from the first main surface to the second main surface, based on the peak interval; and
a temperature calculation unit which calculates the temperature of the substrate based on the optical path length.
8. (canceled)
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 image-taking lens system for forming an image on an imaging element, said lens system comprising from an object side:
a first lens having a positive power;
a cemented lens of a second lens having a negative power and a third lens having a positive power; and
a fourth lens whose concave face is directed toward the image side and having a meniscus shape,
wherein the following conditional expression is fulfilled,
|ff23|<0.4
where f: focal length of the entire system
f23: total focal length of the second and third lenses.
2. An image-taking lens system according to claim 1, further comprising an aperture stop arranged in the object side of said first lens.
3. An image-taking lens system according to claim 1, wherein the following conditional expression is fulfilled,
|ff4|<0.15\u2003\u2003(2)
where f4: focal length of the fourth lens.
4. An image-taking lens system according to claim 1, wherein the following conditional expression is fulfilled,
0.1<d7f<0.4
where d7: thickness on the axis of the fourth lens.
5. An image-taking lens system according to claim 1, wherein the image side surface of the fourth lens is aspherical.
6. An image-taking lens system according to claim 1, wherein the following conditional expression is fulfilled,
0.1<(r2+r3)(r2\u2212r3)<0.9
where r2: radius of curvature on the object side surface of the first lens,
r3: radius of curvature on the image side surface of the first lens.
7. An image taking apparatus comprising:
imaging elements for converting an optical image to an electrical signal; and
an image-taking lens system for forming an optical image of the object on a receiving surface of said imaging elements,
said lens system including from the object side:
a first lens having a positive power;
a cemented lens of a second lens having a negative power and a third lens having a positive power; and
a fourth lens whose concave face is directed toward the image side and having a meniscus shape,
wherein the following conditional expression is fulfilled,
|ff23|<0.4
where f: focal length of the entire system
f23: total focal length of the second and third lenses.
8. A digital apparatus comprising an imaging unit which includes imaging elements for converting an optical image to an electrical signal, and an image-taking lens system for forming an optical image of the object on a receiving surface of said imaging elements,
said lens system including from an object side:
a first lens having a positive power;
a cemented lens of a second lens having a negative power and a third lens having a positive power; and
a fourth lens whose concave face is directed toward the image side and having a meniscus shape,
wherein the following conditional expression is fulfilled,
|ff23|<0.4
where f: focal length of the entire system
f23: total focal length of the second and third lenses.