Image Sensor Color Filter Layout for Boundary Sensitivity Uniformity
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Solution Overview
Problem
The presence of a light shielding film in imaging devices creates a step between the pixel section and the optical black section, leading to non-uniform film thickness of color filters and increased sensitivity unevenness in pixels near the boundary, as obliquely incident light can pass through the optical black section and affect adjacent pixels.
Innovation Solution
Incorporating a low refractive index material between the filter components of the color filter in the pixel section, but not in the optical black section, to reduce the step height and prevent light from entering the pixel section, thereby maintaining uniform film thickness and reducing sensitivity unevenness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a light shielding film is disposed on the light shielding section, then light shielding function is improved, but a step is generated between the pixel section and the light shielding section causing non-uniform film thickness and sensitivity unevenness
Solution Approach 1:
A low refractive index material is introduced as an intermediary substance between the color filter and the light shielding film. This intermediate layer fills the step depression caused by the light shielding film, enabling the color filter to be formed with uniform thickness across both the pixel section and the light shielding section, thereby eliminating sensitivity unevenness while maintaining effective light shielding
Solution Approach 2:
The refractive index parameter of the material layer is changed by using a low refractive index material (refractive index of 1.3 or less) in the step region. This parameter change allows the material to function as an effective optical intermediary that reduces reflection and enables uniform color filter formation, solving both the light shielding requirement and the film thickness uniformity issue
2Object-affected harmful factors
If the light shielding film has thickness, then light shielding capability is improved, but sensitivity unevenness of pixels near the boundary increases due to the step and oblique light transmission
Solution Approach 1:
The low refractive index material acts as an optical intermediary that fills the step depression at the boundary between pixel and light shielding sections. This intermediary structure prevents oblique light from the light shielding section from reaching pixels near the boundary, eliminating the sensitivity unevenness caused by the step while preserving the light shielding film's thickness and shielding capability
Solution Approach 2:
The low refractive index material is selectively applied only in the step depression region between the color filter and the light shielding film, not uniformly across the entire structure. This localized application provides the necessary optical correction at the boundary region without affecting the overall structure, maintaining both light shielding capability and pixel sensitivity uniformity
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 ensures uniform film thickness near the boundary, suppresses light transmission from the optical black section to adjacent pixels, and reduces sensitivity unevenness, enhancing imaging device performance.
Implementation Method 1
a low refractive index material that is provided on one surface side of the semiconductor layer and has a refractive index lower than a refractive index of the color filter
Implementation Method 2
an optical black section that is provided in the semiconductor layer and includes a light shielding film that shields light
Data Source
AI summary
There is provided an imaging device capable of reducing sensitivity unevenness of a pixel located near a boundary between a pixel section and an optical black section. An imaging device includes a semiconductor layer, a pixel section that is provided in the semiconductor layer and receives light from an object, an optical black section that is provided in the semiconductor layer and includes a light shielding film that shields light, a color filter provided on one surface side of the semiconductor layer, and a low refractive index material that is provided on one surface side of the semiconductor layer and has a refractive index lower than a refractive index of the color filter. The pixel section and the optical black section are adjacent to each other. The low refractive index material is disposed between filter components of the color filter in the pixel section, and is not disposed in the optical black section.