Phase Detection Pixel Layout for Accurate Autofocus Image Sensors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Image sensors face challenges in accurately detecting phase differences under various image capturing conditions, which affects autofocusing performance.
Innovation Solution
The image sensor design includes a substrate with both image sensing pixels and phase detection pixels, featuring a light blocking pattern, color filters, and a microlens layer with integrated filling portions and microlenses made of the same light-transmitting material, ensuring optimal light transmission and reception for phase detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional microlens structures are used in phase detection pixels, then manufacturing is simpler, but phase detection accuracy deteriorates due to interface reflections and light loss
Solution Approach 1:
The patent merges the filling portion and microlens into a single integrated structure formed from the same light-transmitting material. This eliminates the interface between separate components, reducing light loss from reflections and improving phase detection accuracy while maintaining manufacturing feasibility through unified formation processes
2Loss of energy
If microlenses are at different heights, then manufacturing is easier, but light transmission efficiency deteriorates
Solution Approach 1:
By forming both the filling portion and microlens from the same light-transmitting material in an integrated structure, the patent ensures they are naturally at the same height. This eliminates height misalignment issues and maximizes light transmission efficiency through the phase detection pixel
3Productivity
If separate filling portions and microlenses are used, then manufacturing flexibility is higher, but light reception capability deteriorates due to interface reflections
Solution Approach 1:
The integrated structure of the filling portion and microlens formed from the same material eliminates interfaces that cause light reflections and losses. This improves light reception capability while the unified formation process maintains manufacturing flexibility through standardized fabrication steps
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 design enhances the image sensor's ability to accurately detect phase differences, improving autofocusing capabilities across different conditions.
Implementation Method 1
a microlens layer including a plurality of first microlenses respectively disposed on the plurality of color filters, at least one filling portion disposed in the at least one second space, and at least one second microlens disposed on the at least one filling portion
Implementation Method 2
a substrate including a plurality of first pixels configured to generate image data and a plurality of second pixels configured to detect phase information of light incident to the plurality of pixels
Data Source
AI summary
An image sensor includes first through fourth pixels. The first pixel includes a first color filter, a first photoelectric conversion device (PD), and a first microlens. The second pixel includes a second PD and a first filling portion. The third pixel includes a third PD and a second filling portion. The fourth pixel includes a fourth PD, a second microlens, and a second color filter different from the first color filter. The second pixel is adjacent to the first pixel. The third pixel is adjacent to the second pixel. The second and third pixels do not comprise any one of a red, blue, and green color filter. Each of the first and second filling portions is configured to transmit light of wavelengths corresponding to blue, red, and green to the second and third PDs, respectively. The first color filter is configured to transmit light of the wavelength corresponding to blue.