Light Guiding Layers for LCD In-Screen Fingerprint Identification
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Solution Overview
Problem
Current in-screen fingerprint identification technologies are not applicable to liquid crystal display (LCD) screens due to their different lighting principles and structures, specifically because the backlight module is opaque, preventing the use of OLED-based fingerprint identification schemes.
Innovation Solution
An in-screen fingerprint identification apparatus for LCD panels is designed, comprising a display panel with a backlight module, a liquid crystal layer, and a cover glass, where light guiding layers on the cover glass direct light from a light source to a fingerprint identification area, and a photosensor receives the reflected light to detect fingerprints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If OLED-based fingerprint identification scheme is used, then fingerprint identification can be achieved, but it is not applicable to LCD screens due to opaque backlight module
Solution Approach 1:
The patent introduces a light guiding layer as an intermediary component between the light source and the fingerprint identification area. This layer guides light from the light source through the opaque backlight module structure to reach the fingerprint sensing area, enabling fingerprint identification on LCD screens without requiring the display to be transparent like OLED.
2Reliability
If backlight module is made opaque for LCD structure, then LCD display function is maintained, but light transmission for fingerprint identification is blocked
Solution Approach 1:
The patent segments the light transmission path by introducing a dedicated light guiding layer that creates a specific optical channel through the backlight module structure. This allows light to be transmitted through the otherwise opaque LCD structure by guiding it along a predetermined path, separating the display function from the fingerprint identification function while maintaining both.
3Adaptability or versatility
If light guiding layers are added to guide light through cover glass, then in-screen fingerprint identification is enabled, but device structure becomes more complex
Solution Approach 1:
The patent merges the light guiding function with the existing cover glass structure by forming the light guiding layer on or integrated with the cover glass. This integration approach combines multiple functions (protection, light guidance, and fingerprint sensing interface) into a single structural element, reducing overall device complexity compared to adding separate components.
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 enables optical fingerprint identification on LCD screens by guiding light emitted by the light source through reflection in the cover glass to the fingerprint identification area, allowing for effective in-screen fingerprint detection and verification.
Implementation Method 1
light emitted by the light source after being reflected in the cover glass is guided to the fingerprint identification area
Implementation Method 2
the photosensor is disposed in the display panel and corresponds to the fingerprint identification area to receive an optical signal of the light source emitted by the light source after being reflected by the finger
Data Source
AI summary
An in-screen fingerprint identification apparatus includes a display panel and a fingerprint identification module. The display panel includes a backlight module, a liquid crystal layer, and a cover glass, which are sequentially stacked. The cover glass includes a fingerprint identification area. The fingerprint identification module includes a light source, a photosensor, and light guiding layers disposed on the cover glass. The light guiding layers at least cover portions of opposite sides of the cover glass, respectively, such that light emitted by the light source after being reflected in the cover glass is guided to the fingerprint identification area. The photosensor is disposed in the display panel and corresponds to the fingerprint identification area to receive an optical signal of the light source emitted by the light source after being reflected by a finger in the fingerprint identification area.