# US 10,309,836 B2 · Collimation evaluation device and collimation evaluation method

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- Number: US 10,309,836 B2
- Document ID: US10309836B2
- Status: Granted
- Kind: B2
- Application number: 15/331,036
- Filed: 2016-10-21
- Published: 2017-07-13
- Granted: 2019-06-04
- Earliest claimed: 2015-08-25
- Assignees: Hamamatsu Photonics K.K.
- Applicants: Hamamatsu Photonics K.K.
- Inventors: Junji Okuma; Yasunori Igasaki; Yasunaga Nara
- Web page: https://patentgrep.com/patent/US10309836B2

## CPC

- G01J 9/0215: {by shearing interferometric methods}
- G01J 2009/0223: {Common path interferometry; Point diffraction interferometry}
- G01J 2009/0234: {Measurement of the fringe pattern}
- G01J: MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY (light sources F21, H01J, H01K, H05B; investigating properties of materials by optical means G01N)

## Abstract

A collimation evaluation device includes a first reflection member, a second reflection member, a screen, and a housing. A first reflection surface of the first reflection member and a first reflection surface of the second reflection member face each other and are parallel to each other. Further, interference fringes are formed on the screen by light L12 reflected on the first reflection surface of the first reflection member and a second reflection surface of the second reflection member and light L21 reflected on a second reflection surface of the first reflection member and the first reflection surface of the second reflection member, and collimation of incident light is evaluated on the basis of a direction of the interference fringes.

## Claims

### Claim 1

A collimation evaluation device comprising:
a first reflection member having a first reflection surface for reflecting a part of incident light and a second reflection surface for reflecting light transmitted through the first reflection surface in the incident light;
a second reflection member having a first reflection surface for reflecting a part of light emitted from the first reflection member and a second reflection surface for reflecting light transmitted through the first reflection surface in the light; and
an observation unit configured to observe light L11 reflected on the first reflection surface of the first reflection member and the first reflection surface of the second reflection member, light L12 reflected on the first reflection surface of the first reflection member and the second reflection surface of the second reflection member, light L21 reflected on the second reflection surface of the first reflection member and the first reflection surface of the second reflection member, and light L22 reflected on the second reflection surface of the first reflection member and the second reflection surface of the second reflection member, and configured to enable interference fringes formed by the light L12 and the light L21 to be observed, wherein
the first reflection surface of the first reflection member and the first reflection surface of the second reflection member face each other and are parallel to each other,
an incidence plane is defined as a plane parallel to both the incident light and the reflected light, and the first reflection surface and the second reflection surface are non-parallel to each other in a direction parallel to both the incidence plane and the first reflection surface, in both or one of the first reflection member and the second reflection member,
the observation unit is configured such that incident regions of the light L12 and the light L21 overlap each other and do not coincide with each other on the observation unit, the interference fringes are formed on an overlapped region, and the light L11 and the light L22 are not incident on the overlapped region being an interference fringe formation region, and
the collimation evaluation device is configured to evaluate collimation of the incident light on the basis of a direction of the interference fringes formed by the light L12 and the light L21 on the observation unit.

### Claim 2 (depends on 1)

The collimation evaluation device according to claim 1, wherein both or one of the first reflection member and the second reflection member is configured to be parallelly movable or rotationally movable.

### Claim 3 (depends on 1)

The collimation evaluation device according to claim 1, wherein the collimation evaluation device is configured to evaluate a beam profile of the incident light on the basis of the light L11 or the light L22 incident on the observation unit.

### Claim 4

A collimation evaluation method comprising:
using a first reflection member having a first reflection surface for reflecting a part of incident light and a second reflection surface for reflecting light transmitted through the first reflection surface in the incident light,
a second reflection member having a first reflection surface for reflecting a part of light emitted from the first reflection member and a second reflection surface for reflecting light transmitted through the first reflection surface in the light, and
an observation unit configured to observe light L11 reflected on the first reflection surface of the first reflection member and the first reflection surface of the second reflection member, light L12 reflected on the first reflection surface of the first reflection member and the second reflection surface of the second reflection member, light L21 reflected on the second reflection surface of the first reflection member and the first reflection surface of the second reflection member, and light L22 reflected on the second reflection surface of the first reflection member and the second reflection surface of the second reflection member, and configured to enable interference fringes formed by the light L12 and the light L21 to be observed;
causing the first reflection surface of the first reflection member and the first reflection surface of the second reflection member to face each other and to be parallel to each other;
defining an incidence plane as a plane parallel to both the incident light and the reflected light, and causing the first reflection surface and the second reflection surface to be non-parallel to each other in a direction parallel to both the incidence plane and the first reflection surface, in both or one of the first reflection member and the second reflection member;
causing incident regions of the light L12 and the light L21 to overlap each other and not to coincide with each other on the observation unit, the interference fringes to be formed on an overlapped region, and the light L11 and the light L22 to be not incident on the overlapped region being an interference fringe formation region;
observing the interference fringes formed by the light L12 and the light L21 on the observation unit; and
evaluating collimation of the incident light on the basis of a direction of the observed interference fringes.

### Claim 5 (depends on 4)

The collimation evaluation method according to claim 4, wherein both or one of the first reflection member and the second reflection member is parallelly movable or rotationally movable.

### Claim 6 (depends on 4)

The collimation evaluation method according to claim 4, wherein a beam profile of the incident light is evaluated on the basis of the light L11 or the light L22 incident on the observation unit.