Crossed Lens Sheet Unit for Thin Light Field Imaging
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Solution Overview
Problem
The challenge of achieving high image quality while reducing the thickness and size of cameras in portable terminals, particularly in light field cameras, is hindered by the need for multiple lenses and alignment issues between partition walls and microlens arrays, as well as the occurrence of noise due to infrared rays and deformation from heat generation.
Innovation Solution
A lens sheet unit comprising two optical sheets with integrated light transmission and absorption parts, which eliminates the need for multiple lenses and partition walls, allowing for thinner imaging modules and devices that suppress heat-induced deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If an imaging lens including a plurality of sheets of lenses is used to capture high image quality, then image quality is improved, but the thickness of the camera increases
Solution Approach 1:
The patent combines multiple lens sheets into a single integrated lens sheet that integrates both light transmission and light absorption functions. This merging eliminates the need for separate partition wall sheets and multiple lenses, reducing the overall thickness from approximately 4-7mm to a much thinner configuration while maintaining the optical functionality required for high image quality in light field cameras
Solution Approach 2:
The lens sheet is designed with multi-functionality, where each lens portion serves dual purposes: transmitting light for imaging and absorbing light to prevent overlap between adjacent lens images. This eliminates the need for separate partition walls and supports, reducing structural complexity and thickness while maintaining optical performance
2Manufacturing precision
If a partition wall sheet is disposed to prevent overlap of images, then image quality is improved, but alignment difficulty increases
Solution Approach 1:
The patent merges the partition wall function directly into the lens sheet structure by forming light absorption portions between adjacent light transmission portions. This integration eliminates the need for separate partition wall sheets and their associated alignment procedures, making manufacturing significantly easier while preventing image overlap
Solution Approach 2:
The lens sheet is segmented into alternating light transmission portions and light absorption portions, where each segment serves a specific optical function. This segmentation is achieved through a single molding process, eliminating the need for separate alignment of multiple components
3Manufacturing precision
If an infrared ray cut filter is disposed to prevent noise, then image quality is improved, but device complexity increases
Solution Approach 1:
The patent integrates the infrared ray absorption function directly into the lens sheet by incorporating an infrared ray absorbing layer within the lens material itself. This merging eliminates the need for a separate infrared ray cut filter, reducing device complexity and the number of components while maintaining the ability to prevent noise from infrared rays
4Ease of manufacture
If the microlens array is made of resin to reduce cost, then manufacturing cost is reduced, but heat-induced deformation occurs
Solution Approach 1:
The patent modifies the material parameters of the resin by incorporating infrared ray absorbing materials and optimizing the resin composition to reduce the coefficient of thermal expansion. This allows the use of cost-effective resin materials while minimizing heat-induced deformation through parameter optimization rather than requiring expensive alternative materials
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 configuration enables a significant reduction in thickness and weight, improves image quality, and reduces production costs by simplifying assembly and alignment, while maintaining high spatial resolution and enabling light field camera functions.
Implementation Method 1
a plurality of light transmission parts 111 which have a columnar shape extending in one direction along a sheet surface, and are arranged in a direction that intersects the extension direction
Implementation Method 2
a plurality of light absorption parts 113 which are disposed alternately with the light transmission parts 111 along the arrangement direction of the light transmission parts 111
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
The present invention relates to an imaging module, an imaging device comprising the imaging module and a lens sheet unit that is used in an imaging module. In an embodiment, the imaging module comprises an imaging element unit (10) in which a plurality of pixels, which convert incident light into an electric signal, are two-dimensionally arranged; and a lens sheet unit (10) that is disposed on a further light incident side in comparison to the imaging element unit. The lens sheet unit includes a lens sheet (11) comprising light transmission parts (111) having a columnar shape, each of which includes a unit lens shape (112) having a convex shape on one surface side; light absorption parts (113) which are arranged alternately with the light transmission parts; and an infrared ray shielding layer (115) that is provided on a further rear surface side in comparison to the light transmission parts in the thickness direction of the lens sheet. The lens sheet unit further includes a second lens sheet (12) on a subject side of the lens sheet or an imaging element unit side along an optical axis direction. The second lens sheet includes second light transmission parts (121) which have a columnar shape, each of which including a second unit lens shape having a convex shape on one surface side, and second light absorption parts. When viewed in the optical axis direction, arrangement directions of the light transmission parts and of the second light transmission parts intersect each other at an angle α.