Terahertz Ring Beam Inspection via Rotary Mirror

Solution Overview

Problem

Existing high-speed and large-area inspection methods using terahertz waves face limitations in movement speed and maximum scanning distance due to the size and weight requirements of optical scan heads, particularly in beam scanning methods which need large mirrors for high resolution.

Innovation Solution

The use of a ring beam forming system with a rotary mirror and axicon lenses to generate and focus terahertz waves, allowing for high-speed inspection with a compact optical scan head by forming line beams for rapid line scanning and optimizing resolution based on surface states.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a large optical aperture (numerical aperture) is used in beam scanning method to obtain high resolution, then resolution is improved, but the size and weight of the mirror and scan head become excessively large

Engineering Contradiction:

ImproveresolutionVSAvoidscan head weight

Core Design Contradiction:

Measurement precisionVSWeight of moving object

Solution Approach 1:

The patent replaces the conventional mechanical beam scanning system with a spatial light modulator (SLM) based optical field modulation system. The SLM electronically controls the phase and amplitude of light waves to shape and steer beams without mechanical moving parts, eliminating the need for large heavy mirrors while maintaining high resolution through precise optical field control

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces dynamic control of optical fields through SLM that can rapidly change beam patterns, focusing points, and scanning paths electronically. This dynamic optical control replaces static mechanical scanning systems, enabling high-resolution imaging with a compact, lightweight scan head that can adapt its optical configuration in real-time

Inventive Principle:

Principle #15Dynamics

2Measurement precision

If a large optical aperture (numerical aperture) is used in beam scanning method to obtain high resolution, then resolution is improved, but the volume of the scan head becomes excessively large

Engineering Contradiction:

ImproveresolutionVSAvoidscan head volume

Core Design Contradiction:

Measurement precisionVSVolume of moving object

Solution Approach 1:

The patent replaces the conventional mechanical beam scanning system with a spatial light modulator (SLM) based optical field modulation system. The SLM electronically controls the phase and amplitude of light waves to shape and steer beams without mechanical moving parts, eliminating the need for large heavy mirrors while maintaining high resolution through precise optical field control

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces dynamic control of optical fields through SLM that can rapidly change beam patterns, focusing points, and scanning paths electronically. This dynamic optical control replaces static mechanical scanning systems, enabling high-resolution imaging with a compact, lightweight scan head that can adapt its optical configuration in real-time

Inventive Principle:

Principle #15Dynamics

3Productivity

If mechanical scanning method is used to inspect large area at high speed, then inspection speed is improved, but the movement speed of the scan head is limited

Engineering Contradiction:

Improveinspection speedVSAvoidscan head movement speed

Core Design Contradiction:

ProductivityVSSpeed

Solution Approach 1:

The patent replaces the conventional mechanical scanning system with an SLM-based optical field modulation system that electronically steers and shapes beams. This eliminates mechanical inertia and friction limitations, allowing instantaneous changes in scanning speed and direction while maintaining high inspection speeds across large areas

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces dynamic control of optical fields through SLM that can rapidly change beam patterns, focusing points, and scanning paths electronically. This dynamic optical control replaces static mechanical scanning systems, enabling high-resolution imaging with a compact, lightweight scan head that can adapt its optical configuration in real-time

Inventive Principle:

Principle #15Dynamics

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach enables high-resolution, high-speed inspection over large areas with reduced size and weight of the optical scan head, facilitating rapid line scanning and optimized inspection based on surface states, thereby overcoming previous limitations in movement speed and scanning distance.

Implementation Method 1

a terahertz wave generation portion (110) configured to generate a terahertz wave

Methodology Applied

Scientific EffectTerahertz wave generation: Electromagnetic Induction

Implementation Method 2

a first forming portion configured to form a terahertz Bessel beam by using the terahertz wave incident from the terahertz wave generation portion

Methodology Applied

Scientific EffectBessel beam formation: Diffraction

Implementation Method 3

a second forming portion configured to form a ring beam by using the terahertz Bessel beam

Methodology Applied

Scientific EffectRing beam formation: Refraction

Implementation Method 4

a rotary mirror configured to reflect the ring beam formed by the ring beam forming portion while rotating to allow the ring beam to be focused on an inspection target object

Methodology Applied

Scientific EffectBeam reflection and focusing: Reflection

Implementation Method 5

a detector configured to detect a ring beam generated from the inspection target object

Methodology Applied

Scientific EffectTerahertz wave detection: Photoelectric Effect

Data Source

PatentUS11635377B2Device for inspecting large area high speed object

Publication Date: 2023.04.25 KOREA FOOD RES INST

AI summary

A high-speed device, for inspecting a large area of an object, which includes: a terahertz wave generation portion configured to generate a terahertz wave; a ring beam forming portion configured to form a ring beam by using the terahertz wave incident from the terahertz wave generation portion; a rotary mirror configured to reflect the ring beam formed by the ring beam forming portion while rotating to allow the ring beam to be incident on an inspection target object; and a detector configured to detect a ring beam generated from the inspection target object.