Title:
NOTCH FILTER
Document Type and Number:
WIPO Patent Application WO/2023/189562
Kind Code:
A1
Abstract:
[Problem] To provide a notch filter with a wider free filter region. [Solution] A notch filter 1 has a free filter region, that is, a wavelength range that allows the transmission of light, and one or more stop bands which are disposed between upper and lower limits of the free filter region and which suppress the transmission of light in a predetermined wavelength range. The notch filter 1 comprises a base material 2 and an optical multilayer film 4 formed directly or indirectly on a base material surface M, which is the surface of the base material 2. The optical multilayer film 4 is formed on the basis of a basic filter repetition structure in which a basic filter structure comprising alternating low refractive index layers L formed from a low refractive index material and high refractive index layers H formed from a high refractive index material is repeated several times. The thickness of each layer in the optical multilayer film 4 corresponds to a modulation thickness sequence in which modulation is added at a different period from a basic period based on the number of layers in the basic filter structure to a basic thickness sequence in which the thickness of each layer in the basic filter repetition structure is arranged in order from the base material 2 side.
Inventors:
SUGIURA MUNEO (JP)
Application Number:
PCT/JP2023/009926
Publication Date:
October 05, 2023
Filing Date:
March 14, 2023
Export Citation:
Assignee:
TOKAI OPTICAL CO LTD (JP)
International Classes:
G02B5/28
Foreign References:
| JP2008242000A | 2008-10-09 | |||
| JP2006023471A | 2006-01-26 |
Attorney, Agent or Firm:
ISHIDA Yoshiki (JP)
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