Image Sensor Bias Voltage Control for Global Shutter
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Solution Overview
Problem
Conventional image sensors and photovoltaic devices face limitations in sensitivity, dynamic range, and response time, particularly in achieving high dynamic range and rapid temporal response while minimizing dark current and noise.
Innovation Solution
The development of optically sensitive devices with a p-type semiconductor material and specific circuitry configurations that apply a bias voltage, utilizing quantum dots and engineered interfaces to enhance electron lifetime, responsivity, and surface recombination velocity, allowing for high sensitivity and rapid response.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional image sensors use standard silicon photodiodes and electronics, then manufacturing is simplified, but sensitivity and dynamic range are limited
Solution Approach 1:
The patent employs a composite structure combining p-type semiconductor material with specific circuitry configurations. This composite approach enhances sensitivity and dynamic range by leveraging the complementary properties of different materials and circuit designs, resolving the contradiction between improved performance and manufacturing simplicity.
Solution Approach 2:
The invention applies parameter changes by modifying the semiconductor material type to p-type and adjusting circuit parameters such as bias voltage configuration. These parameter modifications enable enhanced sensitivity and dynamic range while maintaining compatibility with existing manufacturing processes.
2Reliability
If image sensors operate with high gain to improve sensitivity, then signal detection is enhanced, but noise and dark current increase
Solution Approach 1:
The patent converts potentially harmful effects by using p-type semiconductor material properties to suppress dark current generation while maintaining high signal detection capability. The specific circuitry configuration is designed to minimize noise amplification that typically accompanies high-gain operation, thereby converting the usual trade-off into a beneficial outcome.
3Speed
If global electronic shutter is implemented to capture high dynamic range images, then temporal resolution is improved, but shutter efficiency decreases
Solution Approach 1:
The invention implements a dynamic global electronic shutter mechanism that adapts its operation based on imaging conditions. This dynamic approach maintains high temporal resolution for capturing high dynamic range images while optimizing shutter efficiency by adjusting the timing and duration of electron transfer operations to minimize energy loss.
4Reliability
If electron lifetime is extended to improve sensitivity, then photocurrent collection is enhanced, but response time increases
Solution Approach 1:
The patent applies local quality by creating specific regions with different electron lifetime characteristics. In the photodetection region, extended electron lifetime enhances photocurrent collection efficiency, while in the readout region, faster electron transfer maintains rapid response time. This spatial differentiation of electron lifetime properties resolves the contradiction between sensitivity and speed.
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
The solution achieves high sensitivity, rapid response times, and efficient photocurrent collection, even in high dynamic range images, with improved shutter efficiency and reduced dark current, enabling applications in video imaging and other demanding scenarios.
Implementation Method 1
optically sensitive material between the first contact and the second contact... providing conversion of photons to electrons
Implementation Method 2
circuitry that applies a bias voltage between the first contact and the second contact... electron transit time from the first contact to the second contact when the bias is applied
Data Source
AI summary
In various embodiments, an electronic device comprises, for example, at least one photosensitive layer and at least one carrier selective layer. Under one range of biases on the device, the photosensitive layer produces a photocurrent while illuminated. Under another range of biases on the device, the photosensitive does not produce a photocurrent while illuminated. A carrier selective layer expands the range of biases over which the photosensitive layer does not produce any photocurrent while illuminated. In various embodiments, an electronic device comprises, for example, at least one photosensitive layer and at least one carrier selective layer. Under a first range of biases on the device, the photosensitive layer is configured to collect a photocurrent while illuminated. Under a second range of biases on the device, the photosensitive layer is configured to collect at least M times lower photocurrent while illuminated compared to under the first range of biases.