Optical test apparatus and optical test method
According to one embodiment, an optical test apparatus includes a first optical system, a second optical system, and an image sensor. The first optical system is configured to pass a light ray of a first wavelength and having telecentricity on an object side for the light ray of the first wavelength. The second optical system is configured to pass a light ray of a second wavelength different from the first wavelength. The image sensor is configured to image an object based on the light ray of the first wavelength having passed through the first optical system and the light ray of the second wavelength having passed through the second optical system.
1. An optical test apparatus comprising:
a first optical system configured to pass a light ray of a first wavelength and having telecentricity on an object side for the light ray of the first wavelength;
a second optical system configured to pass a light ray of a second wavelength different from the first wavelength; and
an image sensor configured to image an object based on the light ray of the first wavelength having passed through the first optical system and the light ray of the second wavelength having passed through the second optical system, wherein
the first optical system further includes a first wavelength selecting filter configured to pass the light ray of the first wavelength, and
the second optical system further includes a second wavelength selecting filter configured to pass the light ray of the second wavelength.
2. The apparatus of claim 1 , wherein the first optical system and the second optical system include at least one shared lens arranged on an optical axis of the first optical system and shared by the first optical system and the second optical system.
3. The apparatus of claim 2 , wherein the optical axis of the first optical system and an optical axis of the second optical system are coaxial with each other.
4. The apparatus of claim 1 , wherein the first wavelength selecting filter and the second wavelength selecting filter are formed integrally as a first color filter.
5. The apparatus of claim 4 , wherein the first color filter is arranged on a focal plane of the shared lens.
6. The apparatus of claim 5 , wherein
in the first color filter, the first wavelength selecting filter and the second wavelength selecting filter are arranged to be rotationally symmetrical with respect to an optical axis of the shared lens, and
the first wavelength selecting filter is arranged on light ray paths of light rays among which a principal ray passes through a focal point of the shared lens.
7. The apparatus of claim 6 , wherein
the second optical system further includes a third wavelength selecting filter configured to pass a light ray of a third wavelength different from the first wavelength and the second wavelength,
the third wavelength selecting filter is arranged in the first color filter to be rotationally symmetrical with respect to the optical axis of the shared lens together with the first wavelength selecting filter and the second wavelength selecting filter, and
the image sensor is configured to coaxially image the light ray of the third wavelength having passed through the second optical system.
8. The apparatus of claim 6 , further comprising
a second color filter arranged adjacent to the shared lens and including a fourth wavelength selecting filter configured to pass the light ray of the first wavelength and a fifth wavelength selecting filter configured to pass the light ray of the second wavelength, both of which are arranged concentrically with respect to the optical axis of the shared lens,
wherein the fifth wavelength selecting filter is arranged on the optical axis of the shared lens.
9. The apparatus of claim 8 , wherein
the shared lens comprises a pair of lenses symmetrical in an optical axis direction, and
the second color filter is arranged between the pair of lenses.
10. The apparatus of claim 1 , wherein
the first optical system further includes a first lens, and an aperture stop arranged on an image side focal plane of the first lens and provided with an aperture on light ray paths of light rays among which a principal ray passes through a focal point of the first lens,
the second optical system further includes a second lens, and
the optical axis of the first optical system as an optical axis of the first lens and the optical axis of the second optical system as an optical axis of the second lens are not coaxial with each other.
11. The apparatus of claim 10 wherein the first wavelength selecting filter is arranged on an aperture plane of the aperture stop, and the first wavelength selecting filter and the aperture stop are formed integrally.
12. The apparatus of claim 1 , wherein the first optical system has telecentricity on an image side.
13. The apparatus of claim 1 , further comprising processing circuitry configured to generate image data for respective colors by performing color separation for image data output from the image sensor, and calculate information pertaining to the object based on the image data for respective colors.
14. The apparatus of claim 13 , wherein the processing circuitry specifies color of the light ray imaged based on the image data for respective colors, and calculates a scattering angle at a point on the object as the information pertaining to the object based on the color of the imaged light ray.
15. The apparatus of claim 13 , wherein the processing circuitry specifies an imaging position of a point on the object in each of the image data for respective colors, and calculates a three dimensional position of the point on the object as the information pertaining to the object based on the plurality of imaging positions.
16. The apparatus of claim 15 , wherein
when an imaging plane of the image sensor is parallel to an x axis and a y axis, and an optical axis of the first optical system is parallel to a z axis,
p and q respectively represent an x coordinate and a y coordinate to indicate an imaging position of the light ray of the first wavelength having passed through the first optical system,
P and Q respectively represent an x coordinate and a y coordinate to indicate an imaging position of the light ray of the second wavelength having passed through the second optical system,
f represents an image side focal length of a lens of the first optical system, and
L represents an optical path length between the imaging plane and the lens of the first optical system,
the processing circuitry calculates an x coordinate, a y coordinate, and a z coordinate to indicate the three dimensional position of the point on the object based on a relationship given by:
[
x
y
z
]
=
[
f
L
-
f
p
f
L
-
f
q
Lf
L
-
f
p
2
+
q
2
P
2
+
Q
2
]
.
.
17. An optical test method comprising:
imaging an object to acquire image data based on a light ray of a first wavelength having passed through a first optical system and a light ray of a second wavelength having passed through a second optical system, the first optical system including a first wavelength selecting filter configured to pass the light ray of the first wavelength, the first optical system having telecentricity on an object side for the light ray of the first wavelength, the second optical system including a second wavelength selecting filter configured to pass the light ray of the second wavelength being different from the first wavelength;
performing color separation for the image data to generate image data for respective colors by; and
calculating information pertaining to the object based on the image data for respective colors.