TDI Image Sensor Exposure Control via Light Mask and Scan Controller
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Solution Overview
Problem
Time delayed integration (TDI) image sensors face non-uniform image levels due to varying exposure times across line sensors when the conveyor belt speed is inconsistent, leading to an uneven scan object image.
Innovation Solution
A TDI image sensor system with a light mask and a scan controller that alternately blocks and exposes line sensors to light, generating exposure control signals to maintain constant exposure times for each line sensor, regardless of conveyor belt speed, using a pixel area with odd-numbered and even-numbered line sensors or a light mask positioned in front of part of each line sensor, and a microlens to enhance light exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the conveyor belt speed varies, then the exposure time in each line sensor becomes non-uniform, but maintaining constant exposure time requires additional control mechanisms
Solution Approach 1:
The pixel array is divided into multiple line sensors arranged in the scan direction, with each line sensor independently controlling charge accumulation and transfer timing. This segmentation allows each line to be exposed for a consistent duration despite conveyor speed variations, as the control system can individually manage the integration period for each line sensor row.
Solution Approach 2:
The system dynamically adjusts the charge transfer timing between line sensors based on the integration period requirements. By making the charge accumulation and transfer process adaptive to maintain constant exposure time across lines, the system compensates for conveyor speed fluctuations without requiring mechanical speed regulation.
2Manufacturing precision
If the conveyor belt moves at non-constant speed, then image levels become non-uniform across the scan, but maintaining constant speed reduces flexibility in handling variable production rates
Solution Approach 1:
The system incorporates a control mechanism that monitors and adjusts charge transfer timing based on the required integration period. This feedback approach ensures that each line sensor accumulates charges for a consistent duration regardless of conveyor speed variations, maintaining image uniformity while allowing the conveyor to operate at variable speeds for different production rates.
3Manufacturing precision
If exposure time varies across line sensors, then image quality becomes non-uniform, but controlling exposure time for each line sensor requires additional control signals and circuitry
Solution Approach 1:
The control system merges the generation of line control signals and exposure control signals into a coordinated sequence that simultaneously manages charge accumulation and transfer across multiple line sensors. By combining these control functions into an integrated timing sequence, the system achieves uniform exposure across all lines while minimizing the complexity of individual control circuits.
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
Ensures uniform image formation and consistent exposure times across all line sensors, regardless of conveyor belt speed, resulting in high sensitivity and controlled average brightness levels.
Implementation Method 1
a light mask configured to block the incidence of light on some of the plurality of line sensors
Implementation Method 2
a microlens positioned in front of the remaining part except the part of each line sensor
Implementation Method 3
a pixel area including a plurality of line sensors
Data Source
AI summary
Disclosed is a time delayed integration (TDI) image sensor capable of exposure control, including a pixel area including a plurality of line sensors, a light mask configured to block the incidence of light on part of the line sensors, and a scan controller configured to generate a line control signal and an exposure control signal based on the line trigger signal and to control movement of charges in the plurality of line sensors based on the generated line control signal and exposure control signal.