US 12,467,739 B2
Height measurement apparatus and height measurement method
Tomonori Nakamura, Hamamatsu (JP); and Kunihiko Tsuchiya, Hamamatsu (JP)
Assigned to HAMAMATSU PHOTONICS K.K., Shizuoka (JP)
Appl. No. 17/797,179
Filed by HAMAMATSU PHOTONICS K.K., Hamamatsu (JP)
PCT Filed Feb. 2, 2021, PCT No. PCT/JP2021/003768
§ 371(c)(1), (2) Date Aug. 3, 2022,
PCT Pub. No. WO2021/161854, PCT Pub. Date Aug. 19, 2021.
Claims priority of application No. 2020-022724 (JP), filed on Feb. 13, 2020.
Prior Publication US 2023/0066638 A1, Mar. 2, 2023
Int. Cl. G01B 11/06 (2006.01); G01B 15/02 (2006.01); G01J 3/02 (2006.01); G01J 9/00 (2006.01); G02B 27/14 (2006.01)
CPC G01B 11/06 (2013.01) [G01B 11/0608 (2013.01); G01B 11/0633 (2013.01); G01B 11/0691 (2013.01); G01B 15/02 (2013.01); G01J 3/027 (2013.01); G01J 9/00 (2013.01); G02B 27/141 (2013.01)] 8 Claims
OG exemplary drawing
 
1. A height measurement apparatus comprising:
a light irradiator configured to irradiate a measurement object with irradiation light comprising a plurality of light fluxes arranged in a direction intersecting an optical axis direction and having different wavelengths, at an angle inclined with respect to a height direction of the measurement object;
a light detector configured to detect light from the measurement object irradiated with the irradiation light, and output wavelength information of the light; and
an analyzer configured to calculate a height of the measurement object based on the wavelength information,
wherein the light detector comprises an optical filter of which a transmittance and a reflectance monotonically change according to a wavelength in a predetermined wavelength range and which separates the light from the object by transmitting and reflecting the light, a first light detector configured to detect a reflected light quantity from light reflected by the optical filter, a first bandpass filter disposed between the optical filter and the first light detector configured to remove light in a wavelength range other than the predetermined wavelength range, a second light detector configured to detect a transmitted light quantity from light transmitted through the optical filter, a second bandpass filter disposed between the optical filter and the second light detector configured to remove light in a wavelength range other than the predetermined wavelength range, and a processor configured to calculate the wavelength information based on a ratio between the reflected light quantity and the transmitted light quantity, and output the wavelength information, and
the light from the measurement object has a spectral luminance peak in the predetermined wavelength range of the optical filter.