Phase Mask Integration on Image Sensor for Lens-less Camera

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Solution Overview

Problem

Conventional phase mask-based lens-less cameras face challenges in maintaining accurate focal distance and alignment, leading to reduced image quality due to placement errors and the use of flexible materials that can bend, complicating assembly and increasing manufacturing costs.

Innovation Solution

A method for manufacturing phase masks directly on an image sensor, eliminating the need for spacers and ensuring consistent focal distance, using a replica mold and photocurable materials to form the phase mask with precise thickness, ensuring the phase shift pattern is maintained without bending, thus simplifying the manufacturing process and improving image quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a phase mask is manufactured separately and disposed at a focal distance from the image sensor using spacers, then the phase mask can be positioned at the required distance, but placement errors and alignment errors occur leading to reduced image quality

Engineering Contradiction:

Improvefocal distance accuracyVSAvoidplacement accuracy

Core Design Contradiction:

Measurement precisionVSManufacturing precision

Solution Approach 1:

The phase mask is integrated directly onto the image sensor substrate, merging two previously separate components (phase mask and image sensor) into a single unified structure. This eliminates the need for spacers and separate positioning, thereby eliminating placement errors and alignment errors while maintaining the required focal distance accuracy.

Inventive Principle:

Principle #5Merging (Combining)

2Ease of manufacture

If flexible materials are used for the phase mask, then the phase mask can be manufactured with the required phase shift pattern, but the material can bend leading to focal distance changes and alignment errors

Engineering Contradiction:

Improvephase shift pattern formationVSAvoidstructural stability

Core Design Contradiction:

Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The material properties of the phase mask are changed from flexible to rigid. By using a rigid material instead of flexible material, the phase mask maintains its structural stability and does not bend, thereby preventing focal distance changes and alignment errors while still allowing for the required phase shift pattern to be formed.

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If spacers are used to maintain focal distance, then the phase mask can be positioned correctly, but the assembly process becomes complicated and manufacturing costs increase

Engineering Contradiction:

Improvefocal distance maintenanceVSAvoidassembly complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The phase mask is integrated directly onto the image sensor substrate, eliminating the need for spacers as separate components. This merging of components simplifies the assembly process by removing the spacer installation step while maintaining the required focal distance through the integrated design.

Inventive Principle:

Principle #5Merging (Combining)

4Measurement precision

If spacers are used to support the phase mask, then the focal distance can be maintained, but manufacturing costs increase due to additional components and assembly steps

Engineering Contradiction:

Improvefocal distance consistencyVSAvoidmanufacturing cost

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The phase mask is integrated directly onto the image sensor substrate, eliminating the need for spacers as separate components. This reduces manufacturing costs by removing the additional materials (spacers) and assembly steps required for separate component mounting, while maintaining focal distance consistency through the integrated design.

Inventive Principle:

Principle #5Merging (Combining)

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 allows for the production of high-quality images without focal length changes or alignment errors, enhancing the durability and cost-effectiveness of lens-less camera modules, suitable for mass production with improved productivity.

Implementation Method 1

arranging a photocurable material for implementing the phase mask on the image sensor to a calculated thickness, placing the replica mold on an upper surface of the photocurable material, and then curing the photocurable material

Methodology Applied

Scientific EffectPhotopolymerization: Photopolymerisation

Data Source

PatentUS12108134B2Methods for manufacturing phase masks and lens-less camera module

Publication Date: 2024.10.01 UI (UNIVERSITY IND FOUNDATION) YONSEI UNIVERSITY

AI summary

A method for manufacturing a phase mask and a lens-less camera module comprises the steps of: obtaining a replica mold on which an inverted phase shift pattern is formed in which a phase shift pattern of a master phase mask spaced apart from an image sensor is inverted; calculating a thickness of a phase mask disposed on the image sensor replacing the master phase mask; arranging a photocurable material for implementing the phase mask on the image sensor to a calculated thickness, placing the replica mold on an upper surface of the photocurable material, and then curing the photocurable material; and removing the replica mold from the top of the phase mask, so that the focal distance change or parallel movement does not occur depending on the position of the phase mask.