Reference Pixel Circuit Digital Signal Comparison for Failure Detection
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Solution Overview
Problem
Existing photoelectric conversion apparatuses lack a suitable configuration and method for inputting an address signal to pixel circuits that include a holding unit for digital signals, which hinders effective checking and accuracy in determining failures within the system.
Innovation Solution
A photoelectric conversion apparatus comprising an effective pixel circuit, a reference pixel circuit, a signal output circuit, and a read control circuit, where the reference pixel circuit holds a digital signal with a predetermined value, allowing for the comparison of this signal with the signal read from the holding unit to check the apparatus for failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pixel circuits include a holding unit for holding a digital signal, then the system can maintain digital signals for processing, but it becomes difficult to input address signals and determine failures accurately
Solution Approach 1:
The patent applies preliminary action by pre-setting reference pixel circuits with known digital signal values before normal operation. These reference circuits are configured in advance to hold specific patterns (e.g., all zeros or all ones) that can be used later for comparison and failure detection, eliminating the need for complex address signal input during operation.
Solution Approach 2:
The patent uses copying by creating reference pixel circuits that replicate the structure and function of effective pixel circuits but with predetermined known values. These copied reference circuits serve as templates for comparing against actual pixel circuit outputs to detect failures without requiring complex addressing mechanisms.
2Reliability
If multiple reference pixel circuits are used to check failures, then failure detection accuracy improves, but the number of circuits and system complexity increases
Solution Approach 1:
The patent applies universality by designing reference pixel circuits that serve multiple functions: they act as both test patterns and reference standards simultaneously. Each reference circuit can be configured to represent different failure modes (row failures, column failures, pixel failures) while maintaining a unified structure, reducing the total number of circuits needed compared to dedicated test circuits for each failure type.
3Measurement precision
If analog signals are used in pixel circuits, then signal processing flexibility is maintained, but noise effects and measurement accuracy deteriorate
Solution Approach 1:
The patent applies mechanics substitution by replacing analog signal processing with digital signal processing in pixel circuits. Instead of using continuous analog voltage levels that are susceptible to noise, the system uses discrete digital values (0 and 1) that are immune to noise effects, thereby improving measurement precision and signal accuracy.
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 accurate failure determination and simplifies address signal generation, reducing the number of reference pixel circuits required and making the system immune to noise effects, thus improving the reliability of failure detection.
Implementation Method 1
an effective pixel circuit (11), each including a photoelectric conversion unit (111)
Data Source
AI summary
A photoelectric conversion apparatus includes an effective pixel circuit, a reference pixel circuit, a signal output unit, and a comparison unit. The effective pixel circuit includes a photoelectric conversion unit, and is configured to be controlled by using a control line and to output a digital signal based on electric charges generated by the photoelectric conversion unit. The reference pixel circuit includes a holding unit for holding the digital signal. The reference pixel circuit is configured to be controlled by using the control line together with the effective pixel circuit. The signal output unit is configured to output a signal to the holding unit so that a first digital signal with a predetermined value is held by the holding unit. The comparison unit is configured to compare the first signal with the digital signal output from the holding unit controlled to hold the first digital signal.