Biometric Imaging Aperture Wavelength Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
As pixel density increases in display technology, light transmittivity decreases, making it difficult to acquire high-quality biometric images using optical sensors located under displays due to reduced light reaching the sensor.
Innovation Solution
A display arrangement with an optical biometric imaging device featuring a controllable aperture and wavelength-selective filter element, allowing the effective aperture size to be adjusted by varying the light wavelength illuminating the biometric object, thereby optimizing imaging properties like depth of field.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If pixel density is increased in display technology, then display resolution is improved, but light transmittivity decreases
Solution Approach 1:
The patent changes the wavelength parameter of light to resolve the contradiction. By selecting specific wavelength ranges (e.g., blue light around 450-480nm), the system exploits the fact that certain wavelengths transmit better through high-density display panels while still providing sufficient illumination for biometric imaging. This parameter change allows the system to maintain both high display resolution and adequate light transmission.
2Manufacturing precision
If light transmittivity is decreased due to high pixel density, then display resolution is improved, but quality of biometric images deteriorates
Solution Approach 1:
The system changes the wavelength parameter of illumination light to optimize biometric image quality under high pixel density displays. By using specific wavelength ranges that maintain better transmission through the display panel, the system compensates for the reduced light transmittivity caused by high resolution, thereby maintaining acceptable biometric image quality.
Solution Approach 2:
The patent introduces a wavelength-selective filter as an intermediary component. This filter mediates between the display panel and the image sensor by selectively transmitting specific wavelength ranges, thereby optimizing the light that reaches the sensor while maintaining the high resolution benefits of the display.
3Measurement precision
If aperture size is increased to allow more light to reach the sensor, then imaging quality is improved, but depth of field decreases
Solution Approach 1:
The patent makes the aperture dynamic by using a wavelength-selective filter that can be adjusted based on the illumination wavelength. The effective aperture size changes dynamically depending on which wavelength range is being used, allowing the system to optimize both imaging quality and depth of field for different lighting conditions and display 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
Enables high-quality biometric imaging by controlling the aperture size based on light wavelength, accommodating varying display light transmission properties without requiring sensor redesign, and allowing for flexible imaging modes to suit different lighting conditions.
Implementation Method 1
a filter element arranged within the aperture and configured to block light within a first wavelength range
Implementation Method 2
a lens arrangement comprising at least one lens configured to focus light reflected by a biometric object onto the image sensor
Implementation Method 3
an image sensor comprising a plurality of photodetector pixels
Data Source
AI summary
A display arrangement comprising an optical biometric imaging device for imaging a biometric object comprising: an image sensor comprising a plurality of photodetector pixels; a lens arrangement comprising at least one lens configured to focus light reflected by a biometric object onto the image sensor; an aperture layer arranged between the object to be imaged and the image sensor, wherein the aperture layer comprises an aperture configured to limit the amount of light reaching the image sensor; and a filter element arranged in the aperture and configured to block light within a first wavelength range, wherein an area of the filter element is smaller than an area of the aperture so that a portion of light within the first wavelength range reaching the aperture layer pass through the aperture.