Under-LCD Optical Sensor Module Pinhole Lens Spatial Resolution
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional fingerprint sensors, particularly in mobile devices, face challenges in minimizing footprint while maintaining high spatial imaging resolution, often requiring large sensor areas and conflicting with the need for compact design.
Innovation Solution
The implementation of an under-LCD optical sensor module that uses the LCD screen's light for optical sensing, incorporating a pinhole layer and lens to enhance spatial imaging resolution, allowing for fingerprint detection without the need for a separate sensor area, and integrating with the display screen to provide both touch sensing and optical imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional fingerprint sensors are used, then fingerprint sensing function is provided, but the sensor footprint is large and conflicts with compact device design
Solution Approach 1:
The patent merges the fingerprint sensor with the LCD display screen by positioning the optical sensor array beneath the LCD panel. The LCD screen serves dual purposes: as a display element and as an illumination source for fingerprint sensing. This integration eliminates the need for separate sensor areas, allowing fingerprint sensing to occur through the display screen itself, thereby reducing overall device footprint while maintaining sensing functionality.
Solution Approach 2:
The LCD display screen is designed to perform multiple functions: it serves as both the visual display interface and the illumination source for fingerprint authentication. The backlight module of the LCD provides the necessary light for optical fingerprint sensing, eliminating the need for dedicated illumination components. This multi-functionality approach reduces the number of separate components needed, thereby minimizing the sensor footprint.
2Area of stationary object
If sensor area is reduced for compact design, then device footprint is minimized, but spatial imaging resolution deteriorates
Solution Approach 1:
The patent introduces a pinhole layer as an intermediary optical element between the LCD screen and the optical sensor array. This pinhole layer acts as a spatial filter that enhances the imaging resolution by blocking stray light and improving the optical path. The combination of the pinhole layer with the lens creates a more precise optical system that can achieve high spatial resolution despite the reduced sensor area, as the pinhole effectively increases the optical contrast and signal quality.
Solution Approach 2:
The patent employs a lens with specific focal length and aperture parameters optimized for the reduced sensor area. By carefully selecting and tuning the optical parameters of the lens (focal length, aperture size, curvature), the system compensates for the smaller sensor area and maintains or even enhances the spatial imaging resolution. The pinhole layer also introduces a parameter change in the optical path by limiting the angular acceptance, which improves resolution.
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 robust and reliable fingerprint sensing with enhanced spatial imaging resolution, reducing the footprint of fingerprint sensors and allowing for integration within the display screen, thus optimizing device design and user experience.
Implementation Method 1
incorporating a pinhole layer and lens to enhance spatial imaging resolution
Implementation Method 2
a lens located between the pinhole layer and the optical sensor array to receive the transmitted probe light from the pinhole and to focus the received probe light onto the optical sensor array
Implementation Method 3
an optical sensor array of optical detectors to convert the received probe light from the LCD screen that carries a fingerprint pattern of the user into detector signals representing the fingerprint pattern
Implementation Method 4
under-(liquid crystal display) LCD screen optical sensor module that captures and detects light from a fiber on top of the LCD screen
Data Source
AI summary
Devices and optical sensor modules are provided for provide on-screen optical sensing of fingerprints by using an under-screen optical sensor module that captures and detects light from a fiber on top of the screen. Various implementations of the under-LCD optical sensor modules are provided, including different optical imaging module designs for under-LCD optical sensing, invisible under-LCD optical sensor modules based on concealing optical transmissive features or regions under the LCD opaque borders and optical sensing of topographical features associated with inner tissues of a finger.