Wavefront Measurement Device Compact Optical System Design

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Solution Overview

Problem

The existing wavefront measuring apparatus is difficult to downsize due to the need for a long optical system to generate a parallel light flux matching the detector array, limiting the ability to shorten the total length of the optical system.

Innovation Solution

Incorporating a first lens array to split and condense light beams, a concave lens to further spread the beams, and a detection unit to calculate the wavefront aberration from the positions of condensing spots, allowing for a shorter optical system length and apparatus size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If a relay optical system is used to expand or reduce the beam diameter to match the detector array aperture, then the measurement can be performed, but the total length of the optical system cannot be shortened and the apparatus cannot be downsized

Engineering Contradiction:
Improvetotal length of optical systemVSAvoidwavefront measurement accuracy
Core Design Contradiction:
Length of moving objectVSMeasurement precision

Solution Approach 1:

The optical system is segmented into functional modules: a first lens array to split the beam, a concave lens to spread the beams, and a detection unit to capture the condensing spots. This segmentation allows each component to perform its specific function with optimized dimensions, enabling overall system compactness while maintaining measurement precision.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from a traditional linear optical path to a multi-dimensional arrangement where the first lens array creates multiple beam paths simultaneously. By utilizing the spatial distribution of condensing spots across the detection unit, the system achieves beam expansion without increasing the linear length of the optical system.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Volume of moving object

If the beam diameter is matched with the aperture width of the detector array using a relay optical system, then the measurement can be performed, but the apparatus size cannot be reduced

Engineering Contradiction:
Improveapparatus sizeVSAvoidoptical system configuration
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

The first lens array and concave lens are combined to achieve both beam splitting and spreading functions within a compact configuration. The detection unit is positioned to capture all condensing spots simultaneously, merging the functions of beam manipulation and measurement into a single integrated assembly that reduces overall apparatus size.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The concave lens acts as an intermediary element between the first lens array and the detection unit. It spreads the radially propagating light beams from the lens array, enabling the detection unit to capture the beams at a closer distance and thereby reducing the required apparatus size while maintaining measurement capability.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

The solution effectively shortens the optical system length, enabling downsizing while maintaining measurement accuracy and performance, and allows for the use of commercially available imaging devices with micro lenses.

Implementation Method 1

a first lens array to split a radially propagating light beam after being emitted from an optical system to be tested and once forming an image, and then to condense each of the split light beams

Methodology Applied
Scientific EffectLight splitting and condensation: Lens

Implementation Method 2

a concave lens to further spread radially the plurality of split light beams from the first lens array

Methodology Applied
Scientific EffectLight spreading: Lens

Implementation Method 3

a detection unit disposed at a position where condensing spots of the plurality of split light beams radially propagating from the first lens array are formed

Methodology Applied
Scientific EffectPosition detection:

Data Source

PatentEP4242621B1Wavefront measurement device and wavefront measurement method
Publication Date: 2025.01.15 MITSUBISHI ELECTRIC CORP
  • EP4242621B1 patent drawingFigure 1
  • EP4242621B1 patent drawingFigure 2
  • EP4242621B1 patent drawingFigure 3

AI summary

The wavefront measuring apparatus includes: a first lens array to split a radially propagating light beam after being emitted from an optical system to be tested and once forming an image, and then to condense each of the split light beams; a detection unit, disposed at a position where condensing spots of the plurality of split light beams radially propagating from the first lens array are formed, to detect the condensing spots; and a control unit to calculate, when the first lens array is at a position of conjugation with the optical system to be tested, in other words, the position where the images of the optical system to be tested are transferred, a transmitted wavefront of the optical system to be tested from barycenter positions of the condensing spots.