Pixel Array With Variable Bit Depth Memory For Image Sensor Area Reduction
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Solution Overview
Problem
Current pixel arrays in image sensors face challenges in reducing area and increasing frame rate, particularly due to limitations in memory bit configurations and data transfer efficiency.
Innovation Solution
The proposed solution involves a pixel array with a matrix configuration, where each pixel has a memory to store reset and sensing values, with a first pixel storing m-bit data and a second pixel storing n-bit data, where n is less than m, and a read circuit that generates image data by processing reset and sensing values. This configuration includes a ramp signal generator and counter block to optimize data generation and transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If all pixels use the same memory bit configuration, then data processing consistency is maintained, but pixel array area increases and frame rate decreases
Solution Approach 1:
The patent applies local quality by differentiating memory bit configurations based on pixel location. First pixels in the first row use m-bit memory while second pixels in subsequent rows use n-bit memory (n < m). This allows the pixel array to maintain sufficient precision for critical areas while reducing memory requirements in other areas, thereby decreasing overall area and improving frame rate.
2Device complexity
If all pixels use the same memory bit configuration, then processing simplicity is maintained, but frame rate decreases due to larger data transfer volume
Solution Approach 1:
The patent implements local quality by assigning different memory bit depths to different pixel locations. First pixels store m-bit data while second pixels store n-bit data, reducing the overall data transfer volume and enabling higher frame rates while maintaining processing simplicity through a systematic differentiation approach.
3Reliability
If memory bit depth is increased for all pixels, then internal noise reduction is improved, but area and data transfer requirements increase
Solution Approach 1:
The patent applies local quality by providing higher bit depth (m-bit) memory only for first pixels that require enhanced noise reduction, while using lower bit depth (n-bit) memory for second pixels. This localized approach maintains reliability where needed while minimizing overall area consumption.
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 the area of the pixel array and image sensor while increasing the frame rate by optimizing memory usage and data transfer efficiency, allowing for more efficient image data processing.
Implementation Method 1
each of the plurality of pixels configured to convert an optical signal into an electrical signal
Data Source
AI summary
Provided are a pixel array and an image sensor. The pixel array includes a plurality of pixels, which are arranged in a matrix form and which convert an optical signal into an electrical signal. The pixel array includes a first pixel arranged in a first row of the pixel array and a second pixel arranged in a second row of the pixel array, wherein each of the first pixel and the second pixel includes a first memory storing a digital reset value according to internal noise, the first memory of the first pixel stores m-bit data (where m is a natural number equal to or greater than 2), and the first memory of the second pixel stores n-bit data (where n is a natural number less than m).