Column Signal Processing Circuit for Solid State Imaging Device
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing solid state imaging devices face challenges in achieving a high signal-to-noise ratio when reading low-resolution picture signals at high speed, particularly due to noise components being added during the signal processing of pixel information in horizontal signal lines.
Innovation Solution
A solid state imaging device configuration that includes a pixel array with a color filter and a column signal processing circuit with adjustable feedback capacitances, allowing for pixel addition and amplification while maintaining a high signal-to-noise ratio, by storing and pre-charging signals in feedback capacitances to combine pixel information from adjacent pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pixel information is read out to horizontal signal line and addition/averaging is performed, then low-resolution picture signals can be read out at high speed, but noise components are also added and averaged causing deterioration of signal-to-noise ratio
Solution Approach 1:
The invention divides the pixel array into multiple independent column units, each with its own feedback capacitance. Addition operations are performed separately in each column before horizontal readout, segmenting the noise accumulation process and preventing global noise averaging that degrades signal quality.
Solution Approach 2:
The feedback capacitances perform addition/averaging operations on pixel signals before the signals are transmitted to horizontal signal lines. This preliminary processing at the column level prevents noise components from being accumulated during subsequent horizontal transmission and processing stages.
2Measurement precision
If a larger number of pixels is used for high resolution still pictures, then definition is improved, but reading low-resolution picture signals at high speed becomes more difficult
Solution Approach 1:
The invention enables dynamic switching between high-resolution mode (reading all pixels individually) and low-resolution mode (performing addition operations in feedback capacitances). This dynamic adaptability allows the system to optimize readout speed based on the required image resolution and application requirements.
Solution Approach 2:
The feedback capacitances serve multiple functions: they provide signal amplification, perform addition/averaging operations for low-resolution readout, and maintain high-resolution capability when needed. This multi-functionality allows a single pixel array to handle both high-definition still images and high-speed low-resolution video feeds.
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 enables the generation of pixel addition signals with improved signal-to-noise ratio, enhancing the quality of low-resolution signal readouts and maintaining consistent output voltage levels across different readout modes.
Implementation Method 1
each of which includes a photoelectric conversion element
Implementation Method 2
a plurality of feedback capacitances which are adjustably connected in parallel to the plurality of analog amplifiers
Data Source
AI summary
When an addition/averaging process is done for pixels in the same color in a unit pixel block in a stage reading pixel information to a horizontal signal line, the addition/averaging process is also done for a noise component added in a signal process from the pixels to the horizontal signal line. Thus, a problem arises in the signal-to-noise ratio. Each of signal processing circuits of a column signal processing circuit part is provided with reverse amplifiers which output signals of pixels transmitted by a vertical signal line at a low impedance, and with feedback capacitances which are adjustably connected in parallel to these reverse amplifiers, the signal processing circuit being disposed at every column. These feedback capacitances are used to do row wise and column wise pixel addition for the pixels in the same color in the unit pixel block to take out pixel signals for a single pixel in simulation.