Wavelength Selecting Device for Iris Identification
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Solution Overview
Problem
Existing fingerprint identification technologies in mobile devices face high manufacturing costs and increased size due to the need for additional infrared (IR) sensing modules for enhanced identification, and IR cut-off filters can block near-infrared (NIR) light, leading to low accuracy and susceptibility to interference.
Innovation Solution
An image sensing apparatus that includes a light source, image sensor, lens, wavelength selecting device, and optical path length adjuster, allowing it to switch between NIR light detection mode and non-detection mode by adjusting the gap between reflectors to alter transmittance, eliminating the need for additional NIR modules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If additional infrared sensing modules are adopted to enhance identification quality, then identification accuracy is improved, but manufacturing costs increase and device size increases
Solution Approach 1:
The existing camera module is designed to perform both general photography and iris identification functions. By adjusting the optical path length of the wavelength selecting device, the same hardware can detect different wavelengths (visible light for photos, NIR light for iris identification), eliminating the need for separate dedicated modules and reducing overall device complexity and size.
Solution Approach 2:
The patent changes the optical path length parameter of the wavelength selecting device to control which wavelengths are transmitted. By adjusting this parameter, the system can switch between detecting visible light (for general imaging) and NIR light (for biometric identification), allowing one module to serve multiple functions without requiring additional hardware.
2Measurement precision
If additional infrared sensing modules are adopted to enhance identification quality, then identification accuracy is improved, but manufacturing costs increase
Solution Approach 1:
The camera module is designed to perform both general photography and iris identification functions. By adjusting the optical path length of the wavelength selecting device, the same hardware can detect different wavelengths (visible light for photos, NIR light for iris identification), eliminating the need for separate dedicated modules and reducing overall device complexity and size.
Solution Approach 2:
The patent combines the iris identification functionality with the existing camera module by integrating a wavelength selecting device that can be adjusted to transmit NIR light. This merging of functions into a single module reduces the total component count and manufacturing complexity compared to having separate dedicated NIR sensing modules.
3Illumination intensity
If IR cut-off filters are used in camera modules, then visible light imaging quality is improved, but NIR light transmission is blocked reducing identification accuracy
Solution Approach 1:
The wavelength selecting device is designed with adjustable optical path length, allowing it to dynamically change its transmission characteristics. When set to one position, it transmits visible light for high-quality photography; when adjusted to another position, it transmits NIR light for accurate iris identification. This dynamic adjustability eliminates the need for fixed IR cut-off filters that would permanently block NIR wavelengths.
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 reduces manufacturing costs and device size while maintaining image quality for general photo-taking and enabling effective biometric identification by selectively allowing NIR light to pass through when needed.
Implementation Method 1
The wavelength selecting device has a first reflector and a second reflector, and a gap exists between the first reflector and the second reflector. A transmittance of the wavelength selecting device for light having at least one predetermined wavelength range when the gap is adjusted to have a first predetermined optical path length is less than a transmittance of the wavelength selecting device for the light having the at least one predetermined wavelength range when the gap is adjusted to have a second predetermined optical path length.
Data Source
AI summary
An image sensing apparatus including a light source, an image sensor, at least one lens, and a wavelength selecting device is provided. The light source is configured to emit an illumination light to irradiate an object. The image sensor is configured to receive a light signal from the object and send an image signal corresponding to the light signal. The at least one lens is located on a transmission path of the light signal and between the object and the image sensor. The wavelength selecting device is located on the transmission path of the light signal and between the object and the image sensor. The wavelength selecting device has a first reflector and a second reflector, and a gap exists between the first reflector and the second reflector. The gap is adapted to be adjusted to have a first predetermined optical path length or a second predetermined optical path length.