Patterned Antireflection Layer for Image Sensor Light Condensation
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Solution Overview
Problem
Existing image sensors face challenges in light use efficiency due to the absorption of light by color filters and reflections from layer boundaries, resulting in significant light loss.
Innovation Solution
An image sensor is designed with a patterned antireflection layer that includes a nano-photonic lens array with periodically and two-dimensionally arranged holes, optimizing light condensation and reducing reflections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a color filter is used to sense light color, then light color discrimination is achieved, but light use efficiency is reduced due to absorption of light not corresponding to the sensed color
Solution Approach 1:
The patent changes the optical parameters of the layer boundaries by introducing a gradient refractive index structure through the patterned antireflection layer. This gradient structure transitions the refractive index gradually from the substrate to air, reducing the abrupt refractive index mismatch that causes reflection. The patterned holes create regions with different effective refractive indices, achieving a gradient effect that minimizes reflection losses across the broadband spectrum while maintaining color filtering functionality.
2Measurement precision
If multiple layers with different refractive indices are stacked to achieve color sensing, then color discrimination capability is improved, but light reflection increases at layer boundaries
Solution Approach 1:
The patterned antireflection layer acts as an intermediary structure between the high-refractive-index substrate and low-refractive-index air environment. The layer with its periodic hole pattern creates intermediate refractive index regions that bridge the optical impedance mismatch between layers. This intermediary structure gradually transitions the optical properties, reducing reflection at each interface while allowing the underlying color filter layers to maintain their discrimination function.
Solution Approach 2:
The antireflection layer incorporates a periodic array of holes creating a porous structure. This porosity enables the layer to achieve an effective refractive index that is lower than the solid material but higher than air, creating a gradient effect. The porous structure scatters and gradually transmits light through multiple interfaces, reducing coherent reflection while maintaining optical transmission for color sensing applications.
3Object-affected harmful factors
If a conventional antireflection layer is applied, then light reflection is reduced, but light condensation and focusing capability is not optimized
Solution Approach 1:
The antireflection layer is segmented into a periodic array of holes rather than being a continuous solid layer. This segmentation creates multiple discrete optical pathways and focusing regions. Each hole acts as an independent optical element that can be optimized for specific wavelength ranges, while collectively they provide both antireflection and light condensation functions. The segmented structure allows better control over light propagation and focusing compared to a uniform layer.
Solution Approach 2:
The patent introduces a periodic spatial modulation in the antireflection layer by creating a two-dimensional array of holes. This dimensional transformation from a uniform 2D plane to a structured 2D pattern with periodic variations enables the layer to perform multiple functions: reducing reflection through refractive index modulation and condensing light through geometric focusing effects. The periodic structure creates diffraction and interference patterns that enhance light concentration at specific regions.
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 implementation of the patterned antireflection layer enhances light use efficiency by minimizing reflections and improving light condensation, leading to a higher resolution image sensor.
Implementation Method 1
a nano-photonic lens array having a light incident surface and including a plurality of nanostructures configured to condense an incident light onto the plurality of first pixels and the plurality of second pixels
Implementation Method 2
an antireflection layer disposed on the light incident surface of the nano-photonic lens array and including a plurality of holes arranged periodically and two-dimensionally
Implementation Method 3
An average refractive index of the antireflection layer may be greater than a refractive index of air and less than an average refractive index of the nano-photonic lens array
Data Source
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AI summary
Provided are an image sensor including a patterned antireflection layer and an electronic apparatus including the image sensor. The image sensor includes a sensor substrate including a plurality of first pixels sensing light having a first wavelength and a plurality of second pixels sensing light having a second wavelength different from the first wavelength, a nano-photonic lens array including a plurality of nanostructures configured to condense an incident light onto the plurality of first pixels and the plurality of second pixels, and an antireflection layer disposed on a light incident surface of the nano-photonic lens array and including a plurality of holes arranged periodically and two-dimensionally, wherein the plurality of holes include a plurality of first holes arranged along a boundary between first and second pixels adjacent to each other and a plurality of second holes disposed to face an inner region of the first pixel or the second pixel.