# US 12,111,486 B2 · Optical filter and imaging lens unit

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- Number: US 12,111,486 B2
- Document ID: US12111486B2
- Status: Granted
- Kind: B2
- Application number: 17/602,731
- Filed: 2020-02-13
- Published: 2022-06-02
- Granted: 2024-10-08
- Earliest claimed: 2019-04-11
- Assignees: Nittoh Inc.
- Applicants: Nittoh Inc.
- Inventors: Keiichi Mochizuki
- Web page: https://patentgrep.com/patent/US12111486B2

## CPC

- G02B 5/206: {comprising particles embedded in a solid matrix}
- G03B 11/00: Filters or other obturators specially adapted for photographic purposes
- G02B 5/0242: {by means of dispersed particles}
- G02B 5/0278: {used in transmission}
- G02B 5/0294: {adapted to provide an additional optical effect, e.g. anti-reflection or filter}
- G02B 7/006: {Filter holders}
- G02B 7/02: for lenses {(supports for magnifying lenses G02B25/002)}
- G02B 7/021: {for more than one lens}
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G03B: APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR (optical parts of such apparatus G02B; photosensitive materials or processes for photographic purposes G03C; apparatus for processing exposed photographic materials G03D)

## Abstract

An optical filter includes: a base material; and a plurality of light scattering particles mixed into the base material. The plurality of light scattering particles include a plurality of scattering elements which differ from each other in a manner of appearance of “scattered light intensity distribution for respective wavelengths”. With such a configuration, it is possible to provide the optical filter which is an optical filter can be manufactured without using a method which roughens the surface of the optical filter and is an optical filter for soft focusing which can suppress the occurrence of an iris phenomenon. It is also possible to provide a lens unit which can suppress the occurrence of an iris phenomenon.

## Claims

### Claim 1

An optical filter comprising:
a base material; and
a plurality of light scattering particles mixed into the base material, wherein
the plurality of light scattering particles contain a plurality of scattering elements which differ from each other in a manner of appearance of “scattered light intensity distribution for respective wavelengths”,
the plurality of light scattering particles are formed of a plurality of particles having a spherical shape and having different sizes from each other, and
wherein assuming an average particle size of the particles each having a spherical shape and contained in the optical filter as Φ and a total number of the particles having a spherical shape as Ns, the optical filter contains 0.1 Ns pieces or more of the particles having an average particle size which falls within a range of from 0.4Φ to 0.6Φ, and 0.1 Ns pieces or more of the particles having an average particle size which falls within a range of from 1.3Φ to 1.8Φ.

### Claim 2 (depends on 1)

The optical filter according to claim 1, wherein the optical filter contains 0.5 Ns pieces or more of particles having a spherical shape and having an average particle size which falls within a range of from 0.9Φ to 1.1Φ.

### Claim 3 (depends on 1)

The optical filter according to claim 1, wherein
the plurality of particles having a spherical shape which are mixed into the base material are different by at least 8 μm or more in a particle size.

### Claim 4

An imaging lens unit comprising:
an imaging lens; and
an optical filter comprising:
a base material; and
a plurality of light scattering particles mixed into the base material, wherein the plurality of light scattering particles contain a plurality of scattering elements which differ from each other in a manner of appearance of “scattered light intensity distribution for respective wavelengths”,
wherein
the optical filter has negative power.

### Claim 5

An imaging lens unit comprising:
an imaging lens; and
an optical filter member having a negative power and including an optical filter comprising:
a base material;
a plurality of light scattering particles mixed into the base material, wherein the plurality of light scattering particles contain a plurality of scattering elements which differ from each other in a manner of appearance of “scattered light intensity distribution for respective wavelengths”; and
the imaging lens unit further comprises:
a transparent member made of the same material as the base material of the optical filter, and integrally formed with the optical filter by being connected to a recessed surface of the optical filter, wherein
power of an integral body formed of the optical filter and the transparent member is substantially set to 0 (zero).