Test Circuit for Image Pickup Signal Receiving Units
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Solution Overview
Problem
Existing image pickup apparatuses face challenges in accurately testing signal receiving units (SRUs) due to impedance differences along signal lines, leading to reduced test accuracy and increased test time, as test signals vary significantly from the source to SRUs in different columns.
Innovation Solution
A test circuit with multiple test signal supply units, such as voltage or current buffers, is employed, where each unit is connected to a unique signal line, reducing impedance differences and allowing for more accurate testing of SRUs by supplying test signals directly to each unit independently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single test signal generator is used to supply test signals to all columns, then the device complexity is reduced, but the measurement precision deteriorates due to impedance differences along signal lines
Solution Approach 1:
The patent divides the single test signal generator into multiple test signal generators, with each generator connected to a specific column or group of columns. This segmentation allows each generator to independently drive its connected SRUs without being affected by impedance variations in other columns, thereby resolving the contradiction between device complexity and measurement precision.
2Measurement precision
If the test is performed after the difference in test signal supplied to the SRUs has become small, then the measurement precision is improved, but the test time increases
Solution Approach 1:
The patent applies preliminary action by performing impedance matching and signal level adjustment before the actual measurement process. Test signal generators are configured with appropriate output impedances and signal levels that account for the specific characteristics of each column's signal line, ensuring that signal differences are minimized from the start rather than requiring waiting time for stabilization.
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 precise measurement and correction of SRU characteristics across columns, improving test accuracy and reducing test time by minimizing signal variations, allowing for testing under conditions similar to image taking operations.
Implementation Method 1
the test signal supply unit is a voltage buffer or a current buffer
Data Source
AI summary
It is disclosed that, as an embodiment, a test circuit includes a test signal supply unit configured to supply a test signal via a signal line to signal receiving units provided in a plurality of columns, wherein the test signal supply unit is a voltage buffer or a current buffer, and the test circuit has a plurality of test signal supply units and a plurality of signal lines, and wherein at least one test signal supply unit is electrically connected to one signal line different from a signal line to which another test signal supply unit is electrically connected.