Image Sensor Autofocus Using Segmented Micro Lenses
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Solution Overview
Problem
Existing digital camera autofocus processes face challenges in accuracy and time consumption, which can result in obscured images or the inability to capture fast-moving objects.
Innovation Solution
The implementation of image sensors with multiple micro lenses of varying focal lengths for both image capturing and detecting units, along with a computing unit that processes error data to adjust the lens module's position using a built-in table, enables faster and more accurate autofocus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional autofocus processes are used, then the image can be captured, but the time consumption is large and accuracy is poor
Solution Approach 1:
The image sensor is segmented into multiple types of pixels (first pixels with first micro lenses for image capturing, second pixels with second micro lenses for focus detection, and third pixels without micro lenses). This segmentation allows simultaneous image capture and focus detection, enabling the autofocus system to determine focus accuracy without delaying the capture process, thus resolving the contradiction between measurement precision and time consumption.
Solution Approach 2:
The micro lenses are pre-configured with different focal lengths on different pixel types during sensor fabrication. The second micro lenses on second pixels are specifically designed with focal lengths suitable for focus detection. This preliminary configuration eliminates the need for real-time lens adjustment during autofocus, reducing time consumption while maintaining accuracy.
2Productivity
If multiple micro lenses with various focal lengths are used, then autofocus accuracy and speed are improved, but device complexity increases
Solution Approach 1:
The image sensor achieves multi-functionality by integrating different pixel types in a single array. First pixels capture images, second pixels detect focus, and third pixels provide additional image data. All pixel types share the same physical substrate and readout circuitry, allowing the system to perform multiple functions without proportionally increasing overall device complexity.
Solution Approach 2:
The patent merges image capturing and focus detection functions into a single integrated sensor array. By combining first pixels, second pixels, and third pixels in one sensor chip with shared readout circuits, the system achieves high-speed autofocus without the complexity of separate detection systems or mechanical moving parts.
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 reduces time consumption and improves autofocus accuracy by allowing for quicker and more precise focusing of images, enabling better capture of moving objects.
Implementation Method 1
Each image capturing unit includes an image capturing pixel and a first micro lens. The first micro lens is disposed in front of the image capturing pixel. The detecting unit has a detecting pixel and a second micro lens with various focal lengths.
Data Source
AI summary
An image sensor, an electric device using the same and a focusing method of the electric device are provided. The image sensor comprises a plurality of image capturing units and a detecting unit. Each image capturing unit includes an image capturing pixel and a first micro lens. The first micro lens is disposed in front of the image capturing pixel. The detecting unit has a focus detecting pixel and a second micro lens. The second micro lens is disposed in front of the image detecting pixel. A length of the second micro lens is different from a length of the first micro lenses.