Black Reference Pixel Infrared Interference Control
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Solution Overview
Problem
Existing image sensing technologies, such as those using CCD or CMOS sensors, face challenges in completely eliminating the influence of near-infrared rays on black reference signals, leading to errors in effective pixel signals.
Innovation Solution
An image sensing apparatus is designed with a control unit that manages charge accumulation in black reference pixels during periods when the object is not illuminated, preventing the entry of infrared light and thus reducing the impact on black reference signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a light shielding film is interposed between the on-chip lens and semiconductor substrate surface, then the influence of infrared rays on black reference signal is reduced, but the influence cannot be completely removed
Solution Approach 1:
An infrared ray absorbing layer is introduced as an intermediary substance between the black reference pixel and the incoming infrared rays. This layer specifically absorbs infrared wavelengths while allowing other wavelengths to pass through, thereby eliminating the harmful infrared influence on black reference signals without affecting the sensor's overall functionality.
Solution Approach 2:
The optical properties of the semiconductor substrate are modified by introducing a specialized infrared absorbing layer with specific absorption characteristics. This changes the substrate's interaction with infrared rays from reflection (which causes the problem) to absorption (which solves the problem), thereby eliminating infrared interference while maintaining normal sensor operation.
2Object-affected harmful factors
If an OB clamp region is set at a position more apart from the effective pixel portion, then the infrared ray influence is reduced, but the technique cannot completely remove the influence
Solution Approach 1:
An infrared ray absorbing layer is introduced as an intermediary substance between the black reference pixel and the incoming infrared rays. This layer specifically absorbs infrared wavelengths while allowing other wavelengths to pass through, thereby eliminating the harmful infrared influence on black reference signals without affecting the sensor's overall functionality.
Solution Approach 2:
The optical properties of the semiconductor substrate are modified by introducing a specialized infrared absorbing layer with specific absorption characteristics. This changes the substrate's interaction with infrared rays from reflection (which causes the problem) to absorption (which solves the problem), thereby eliminating infrared interference while maintaining normal sensor operation.
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 effectively minimizes the influence of infrared rays on black reference signals, enabling the acquisition of accurate black reference signals and improving the overall image sensing performance.
Implementation Method 1
an effective pixel configured to detect an infrared ray returning from the object; a black reference pixel configured to obtain a black reference signal
Data Source
AI summary
An image sensing apparatus senses an image of an object illuminated with illumination light including an infrared ray. the apparatus includes an effective pixel region including an effective pixel configured to detect an infrared ray returning from the object, a black reference pixel region including a black reference pixel configured to obtain a black reference signal, and a control unit configured to control the black reference pixel such that charge accumulation in the black reference pixel for obtaining the black reference signal is performed in a period during which the object is not illuminated with the illumination light.