Photosensitive Sensor With Locally Varying Infrared Filter
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Solution Overview
Problem
Existing photosensitive sensors for vehicles face challenges in maintaining image quality both day and night due to infrared saturation during the day and inadequate performance at night, leading to increased complexity, cost, and reliability issues with dual sensors or removable filters.
Innovation Solution
A single photosensitive sensor with a locally varying filter that modulates infrared filtration, allowing sufficient infrared at night while preventing saturation during the day, by dividing the receiving zone into filtered and unfiltered areas, with the filtered zone typically located at the bottom to mitigate infrared reflection from the road.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an infrared-sensitive sensor is used to detect radiation at night, then night vision capability is improved, but during the day the sensor saturates due to infrared reflection from the road, degrading image quality
Solution Approach 1:
The sensor's receiving zone is divided into multiple zones with different infrared transmission characteristics. Specifically, the sensor includes first photoelectric conversion units with first infrared transmission characteristics and second photoelectric conversion units with second infrared transmission characteristics, allowing different portions of the sensor to handle different levels of infrared radiation appropriately for their respective viewing angles
Solution Approach 2:
Different regions of the sensor are assigned different infrared transmission properties based on their function. The first photoelectric conversion units (typically at larger incident angles) have first infrared transmission characteristics that allow more infrared transmission, while the second photoelectric conversion units (typically at smaller incident angles) have second infrared transmission characteristics that block more infrared, creating local quality variations optimized for each region's specific operational requirements
2Manufacturing precision
If two separate sensors are used (one for daytime with infrared blocking filter, one for nighttime), then image quality for both day and night is improved, but system complexity, cost, and size increase
Solution Approach 1:
Multiple sensors with different infrared transmission characteristics are integrated into a single sensor device. The sensor comprises both first photoelectric conversion units and second photoelectric conversion units within the same sensor structure, sharing common components such as the substrate, connection terminals, and processing circuitry, thereby achieving the functionality of multiple sensors while reducing overall system complexity
Solution Approach 2:
The single sensor device performs multiple functions by utilizing different photoelectric conversion units for different operating conditions. The sensor can simultaneously handle daytime imaging (where infrared blocking is needed) and nighttime imaging (where infrared transmission is beneficial) within the same device, making it universally applicable for both day and night vision requirements
3Manufacturing precision
If a removable infrared filter is used to prevent daytime saturation, then image quality during daytime is improved, but the system requires moving parts and complex detection means, reducing reliability
Solution Approach 1:
Instead of using a removable filter that blocks infrared during the day and is removed at night, the invention inverts the approach by having fixed filters with different transmission characteristics permanently assigned to different photoelectric conversion units. The infrared transmission properties are determined by the incident angle of light, with larger angles (typical of daytime road reflections) directing light to units with infrared-blocking characteristics and smaller angles (typical of nighttime scenes) directing light to units with infrared-transmissive characteristics
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 enables a single sensor to maintain high image quality both day and night without moving parts, reducing complexity, cost, and improving reliability, while avoiding performance compromises in varying sunlight conditions.
Implementation Method 1
the filter is configured to selectively transmit or block infrared radiation based on the incident angle of incoming light
Implementation Method 2
a significant part of the infrared received by the sensor comes from the scattering reflection on the road of the infrared emitted by the sun
Data Source
Figure 1~2
Figure 3~5b
Figure 4a~4c
AI summary
The invention relates to a sensor (C) that is photosensitive to at least a portion of infrared radiation and at least a portion of visible radiation. This sensor is equipped with a filter (F) affecting all or part of the receiving area (Z) of the sensor (C) and capable of filtering radiation at wavelengths to which the sensor is sensitive according to a filtering ratio (f) that varies locally.