US 12,687,433 B2Granted

Circular polarizer detection device and circular polarizer detection method

AssigneesNational Central University, Usun Technology Co., Ltd.

InventorsJu-Yi Lee, You-Jun Lin, Wei-Chen Wong, Hsing-Hsien Tsai

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Abstract

A circular polarizer detection device for detecting a circular polarizer-to-be-detected including a first linear polarizer and a first wave plate is provided. The first linear polarizer has a first transmission axis, the first wave plate has a first fast axis, and there are a preset angle and an error angle between the first transmission axis and the first fast axis. The circular polarizer detection device includes a light source system, a second wave plate and an optical phase demodulation system. A first beam provided by the light source system is converted into a beam-to-be-detected through the circular polarizer-to-be-detected. The beam-to-be-detected enters the rotating second wave plate and then is converted into a second beam. The optical phase demodulation system receives the second beam, generates a phase difference curve, and analyzes a relationship between the rotation angle and the error angle. A circular polarizer detection method is also provided.

Claims17

Dependent claims

A circular polarizer detection device, applicable to detecting a circular polarizer-to-be-detected, the circular polarizer-to-be-detected comprising a first linear polarizer and a first wave plate, the first wave plate being disposed on a side of the first linear polarizer, the first linear polarizer having a first transmission axis, the first wave plate having a first fast axis, there being a preset angle and an error angle between the first transmission axis and the first fast axis, and the circular polarizer detection device comprising:

a light source system, disposed on a side of the circular polarizer-to-be-detected, wherein the first linear polarizer is between the light source system and the first wave plate, the light source system provides a first beam to the circular polarizer-to-be-detected, and the first beam is converted into a beam-to-be-detected through the circular polarizer-to-be-detected;
a second wave plate, disposed on a side of the circular polarizer-to-be-detected away from the light source system, wherein the second wave plate is suitable for rotating, the beam-to-be-detected enters the rotating second wave plate and is converted into a second beam through the second wave plate, the second wave plate has a second fast axis, there is a variable rotation angle γ between the second fast axis and the first transmission axis of the first linear polarizer, and the second beam has a different phase difference as the rotation angle γ varies;
and
an optical phase demodulation system, disposed on a side of the second wave plate away from the circular polarizer-to-be-detected, wherein the optical phase demodulation system receives the second beam, generates a phase difference curve, and analyzes a relationship between the rotation angle γ and the error angle through the phase difference curve.

1 more element

A circular polarizer detection method, applicable to detecting a circular polarizer-to-be-detected, the circular polarizer-to-be-detected comprising a first linear polarizer and a first wave plate, the first wave plate being disposed on a side of the first linear polarizer, the first linear polarizer having a first transmission axis, the first wave plate having a first fast axis, there being a preset angle and an error angle between the first transmission axis and the first fast axis, and the circular polarizer detection method comprising:

providing a light source system, disposed on a side of the circular polarizer-to-be-detected, wherein the first linear polarizer is between the light source system and the first wave plate, the light source system provides a first beam to the circular polarizer-to-be-detected, and the first beam is converted into a beam-to-be-detected through the circular polarizer-to-be-detected;
disposing a second wave plate on a side of the circular polarizer-to-be-detected away from the light source system, wherein the second wave plate is suitable for rotating, the beam-to-be-detected enters the rotating second wave plate and is converted into a second beam through the second wave plate, the second wave plate has a second fast axis, there is a variable rotation angle γ between the second fast axis and the first transmission axis of the first linear polarizer, and the second beam has a different phase difference as the rotation angle γ varies;
and
disposing an optical phase demodulation system on a side of the second wave plate away from the circular polarizer-to-be-detected to receive the second beam and generate a phase difference curve, the optical phase demodulation system parsing the rotation angle γ0 corresponding to a maximum slope of the phase difference curve and calculating the error angle through the rotation angle γ0 corresponding to the maximum slope of the phase difference curve and according to an operational formula.

1 more element

Dependencies are inferred from the claim text.

Facts

Application: 18/826,245Filed 6 Sep 2024
Priority: TW 1121342838 Sep 2023
Published: US 2025/0085165 A113 Mar 2025
Granted: 21 Jul 2026
Term ends: Not estimatedThe source records don’t support an estimate.

Classification7 codes

G01J 4/04
Measuring polarisation of light: polarimeters using electric detection means
G01B 11/272
For testing the alignment of axes: using photoelectric detection means
G02B 5/3025
Polarising elements: polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state
G02B 5/3083
Polarising elements: birefringent or phase retarding elements