Optical Sensor Dual Pixel Wavelength Segmentation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing optical sensors fail to accurately distinguish between visible and infrared light, leading to inaccurate results in low ambient light conditions due to detection of invisible light wavelengths, and require complex manufacturing processes.
Innovation Solution
An optical sensor design featuring an image sensor with two types of pixels, each coated with specific optical films to block unwanted wavelengths, allowing only infrared or visible light to be detected, and a processing unit to generate electrical signals from the pixel data, simplifying the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a prior art visible light sensor is used to detect ambient light, then the sensor can detect visible light, but it inaccurately detects invisible light (IR) wavelengths leading to wrong results
Solution Approach 1:
The sensor is divided into two distinct pixel types: first pixels with optical films for visible light detection and second pixels without optical films for IR light detection. This segmentation allows each pixel type to specialize in detecting specific wavelength ranges, eliminating cross-contamination and improving measurement precision for both visible and IR light separately.
Solution Approach 2:
Different regions of the sensor array have different optical properties. First pixels are equipped with optical films that transmit visible light while blocking IR light, whereas second pixels lack these films and are therefore sensitive to IR light. This local differentiation enables simultaneous accurate detection of both visible and IR wavelengths without interference.
2Object-affected harmful factors
If a multi-layer filter structure with Ag and Si3N4 layers is used to block IR light, then IR light can be blocked, but the manufacturing process becomes complicated reducing product yield and increasing costs
Solution Approach 1:
Instead of adding complex multi-layer filter structures to block IR light, the invention extracts and utilizes the natural property of certain optical films that inherently block IR wavelengths while transmitting visible light. This approach eliminates the need for additional complex manufacturing steps involving multiple material layers.
Solution Approach 2:
The invention changes the optical parameters of the sensor by selecting optical films with specific transmission characteristics that naturally block IR light. By adjusting the optical film selection rather than adding complex filter layers, the patent achieves IR blocking with simpler manufacturing while maintaining visible light transmission.
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 accurate simultaneous detection of IR and visible light, improving accuracy in low light conditions while reducing manufacturing complexity and costs.
Implementation Method 1
a first optical film configured to block light whose wavelength is outside a first predetermined range and a second optical film configured to block light whose wavelength is outside a second predetermined range
Implementation Method 2
The thickness of each layer in the multi-layer filter structure is determined according to Fabry-Perot interference principle
Data Source
AI summary
An optical sensor includes an image sensor, a proximity sensor and a visible light sensor. The image sensor includes a first pixel and a second pixel. The first pixel is coated with a first optical film for blocking light whose wavelength is outside a first predetermined range and a second optical film for blocking light whose wavelength is outside a second predetermined range. The proximity sensor generates an IR signal according to a first exposure value. The visible light sensing unit generates a visible light signal according to the difference between the first exposure and a second exposure value or according to a ratio of the first exposure value to the second exposure value. The first exposure value represents an incident light quantity which is absorbed by the first pixel. The second exposure value represents an incident light quantity which is absorbed by the second pixel.