# US 5,353,070 A · Lens holder which reduces internal reflections

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- Number: US 5,353,070 A
- Document ID: US5353070A
- Status: Granted
- Kind: A
- Application number: 08/070,912
- Filed: 1993-06-04
- Granted: 1994-10-04
- Earliest claimed: 1992-06-08
- Assignees: Matsushita Electric Industrial Co., Ltd.
- Inventors: Katsuaki Mitani; Masayuki Takahashi; Syunsuke Kimura
- Web page: https://patentgrep.com/patent/US5353070A

## CPC

- G02B 27/0018: {with means for preventing ghost images (anti-reflection coatings G02B1/11)}
- G02B 1/11: Anti-reflection coatings
- G02B 7/02: for lenses {(supports for magnifying lenses G02B25/002)}
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS

## Abstract

In a lens-barrel etc. for holding lenses, a thin film composed of a fluororesin compound having a refractive index lower than that of a material constituting the lens-barrel is formed on an inner surface of the lens-barrel, thereby lowering an amount of the reflective light appeared on the inner surface of the lens-barrel.

## Claims

### Claim 1

A lens holder comprising:
a lens-barrel; and
a thin film formed on an inner surface of said lens-barrel, said thin film being composed of a fluororesin compound having a refractive index lower than a refractive index of a material which constitutes said lens-barrel.

### Claim 2

A projection type TV set comprising a blue CRT, a green CRT and a red CRT and three lens holders, respectively coupled to said blue CRT, said green CRT, and said red CRT, each of said lens holders having a thin film of fluororesin compound on an inner surface thereof, wherein
a first thin film in one of said lens holders used for said blue CRT has a thickness which makes a reflectance minimum within a region of wavelength from 420 nm to 480 nm;
a second thin film in one of said lens holders used for said green CRT has a thickness which makes a reflectance minimum within a region of wavelength from 525 nm to 575 nm; and
a third thin film in one of said lens holders used for said red CRT has a thickness which makes a reflectance minimum within a region of wavelength from 580 nm to 620 nm.

### Claim 3

A lens holder comprising:
a lens barrel;
a coupler for coupling said lens barrel with a CRT;
a thin film formed on an inner surface of at least one of said lens-barrel and said coupler, said thin film being composed of a fluororesin compound having a refractive index lower than a refractive index of a material which constitutes said lens-barrel.

### Claim 4 (depends on 2)

A projection type TV set in accordance with claim 2, wherein
each of said lens holders includes a lens-barrel and a coupler for connecting said lens barrel with each of said blue CRT, said green CRT and said red CRT; and
said thin film is formed on the inner surface of at least one of said lens-barrel and said coupler.