Imaging Device Pixel Cell Dynamic Sensitivity Control
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Solution Overview
Problem
Existing imaging devices face challenges in dynamically adjusting pixel cell sensitivity, leading to saturation under high illuminance and limited dynamic range in photography.
Innovation Solution
The imaging device incorporates pixel cells with a photoelectric conversion layer, a pixel electrode, an auxiliary electrode, a counter electrode, and a charge detection circuit, along with a voltage supply circuit and capacitors to individually adjust sensitivity by applying specific voltages, enabling dynamic sensitivity modulation and preventing saturation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a photodiode having a large area is placed in a high-sensitivity pixel cell to expand dynamic range, then sensitivity is improved, but saturation occurs under high illuminance
Solution Approach 1:
The patent applies dynamics by making the pixel cell sensitivity adjustable through voltage control. The pixel cell switches between high-sensitivity and low-sensitivity states by applying different voltages to the auxiliary electrode, allowing the system to adapt to varying illuminance conditions and prevent saturation while maintaining measurement precision across different lighting scenarios.
Solution Approach 2:
The patent changes the electrical parameter (voltage) applied to the auxiliary electrode to modulate pixel cell sensitivity. By varying the voltage, the sensitivity of the pixel cell is dynamically adjusted, enabling the same pixel to function in both high-sensitivity and low-sensitivity modes, thereby preventing saturation under high illuminance while maintaining good sensitivity under low illuminance.
2Use of energy by moving object
If pixel cell sensitivity is increased to capture more light, then low-light performance is improved, but saturation occurs under high illuminance conditions
Solution Approach 1:
The patent implements dynamic sensitivity adjustment by applying different voltages to the auxiliary electrode based on illuminance conditions. Under low illuminance, high voltage is applied to maximize light capture efficiency. Under high illuminance, low voltage is applied to prevent saturation, thus dynamically optimizing light capture efficiency across different lighting conditions.
Solution Approach 2:
The patent changes the voltage parameter applied to the auxiliary electrode to control pixel cell sensitivity. This parameter change enables the pixel cell to capture more light when illuminance is low while preventing saturation when illuminance is high, thereby optimizing light capture efficiency across the full range of lighting conditions.
3Adaptability or versatility
If different sensitivity pixel cells are used to expand dynamic range, then wide dynamic range photography is enabled, but device complexity increases
Solution Approach 1:
The patent applies universality by designing a single pixel cell structure that can perform multiple functions - operating in both high-sensitivity and low-sensitivity modes. The auxiliary electrode enables the same pixel cell to adapt to different illuminance conditions, eliminating the need for separate high-sensitivity and low-sensitivity pixel cells, thus reducing device complexity while maintaining wide dynamic range capability.
Solution Approach 2:
The patent makes the pixel cell dynamically adjustable through voltage control of the auxiliary electrode, allowing a single pixel cell to replace multiple fixed-sensitivity pixel cells. This dynamic capability enables wide dynamic range photography while simplifying the device structure by eliminating the need for heterogeneous pixel cell arrays.
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 solution allows for wide dynamic range photography by suppressing charge saturation and enabling global shuttering with simultaneous exposure of pixels having different sensitivities.
Implementation Method 1
a photoelectric conversion layer having a first surface and a second surface opposite to the first surface
Data Source
AI summary
An imaging device includes a pixel cell including a photoelectric conversion layer having first and second surfaces, a pixel electrode on the first surface, an auxiliary electrode on the first surface, the auxiliary electrode surrounding the pixel electrode and being electrically insulated from the pixel electrode, a counter electrode on the second surface, and a charge detection circuit connected to the pixel electrode; a voltage supply circuit; a first switch switching between electrical connection and disconnection; a first capacitor having one end connected to the auxiliary electrode and the other end held to a predetermined voltage; and a first control circuit connected to the first switch, the first control circuit causing the first switch to switch between electrical connection and disconnection. The voltage supply circuit is connected, through the first switch, to the auxiliary electrode of the first pixel cell and to the one end of the first capacitor.