Fingerprint Light Sensor Layout for Gray Level Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional fingerprint sensing devices experience identification errors due to the degradation of sensing element performance over time, leading to insufficient gray levels in fingerprint images.
Innovation Solution
A light-sensing device with a substrate featuring working and reference light-sensing elements, where the reference elements have a light-blocking structure that shields the light-sensing pattern, allowing for monitoring of deterioration and adjustment of illumination to maintain optimal gray levels, thereby correcting output and improving fingerprint signal quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If working light-sensing elements are continuously exposed to sensing light for fingerprint detection, then fingerprint sensing function is maintained, but the gray level of sensed fingerprint image decreases over time due to sensing element deterioration
Solution Approach 1:
The patent applies preliminary action by exposing reference light-sensing elements to the same sensing light conditions as working elements before actual fingerprint sensing. This pre-exposure allows the reference elements to undergo the same deterioration process, establishing a baseline that accounts for subsequent gray level degradation. The reference elements are exposed to sensing light in advance, so when fingerprint sensing occurs, both working and reference elements have experienced identical light exposure history, enabling accurate compensation for deterioration effects.
Solution Approach 2:
The patent implements feedback by continuously comparing the output signals from working light-sensing elements with those from reference light-sensing elements. The difference between these signals provides real-time information about deterioration effects, which is then used to adjust and compensate the fingerprint sensing results. This closed-loop feedback mechanism dynamically corrects for gray level degradation, maintaining measurement precision despite continuous light exposure.
2Measurement precision
If reference light-sensing elements are disposed beside working light-sensing elements, then monitoring of deterioration is enabled, but light shielding between reference and working elements becomes difficult
Solution Approach 1:
The patent applies dimensionality change by transitioning from lateral placement (beside working elements) to vertical stacking (directly above working elements). This vertical arrangement in the depth dimension allows reference light-sensing elements to be positioned directly above their corresponding working elements without requiring complex lateral light shielding structures. The vertical stacking naturally provides light isolation through the layered structure, simplifying the overall device design while maintaining accurate deterioration monitoring capability.
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 effectively corrects the output gray levels of working light-sensing elements by using reference light-sensing elements to monitor and adjust illumination, reducing identification errors and enhancing fingerprint image quality.
Implementation Method 1
Each of the multiple first reference light-sensing elements, the multiple second reference light-sensing elements, and the multiple third reference light-sensing elements includes the light-sensing pattern and the first light-blocking structure disposed on the light-sensing pattern. The first light-blocking structure of each of the multiple first reference light-sensing elements, the multiple second reference light-sensing elements, and the multiple third reference light-sensing elements shields the light-sensing pattern.
Implementation Method 2
the fingerprint sensing device may sense the image of the fingerprint to be detected according to the sensing light through the sensing element
Data Source
AI summary
A light-sensing device comprises a substrate, multiple first working light-sensing elements, multiple second working light-sensing elements, multiple third working light-sensing elements, multiple first reference light-sensing elements, multiple second reference light-sensing elements, multiple third reference light-sensing elements, a first processing element, and a second processing element. The substrate has a first working area, a second working area, a third working area, a first reference area, a second reference area, and a third reference area. The multiple first working light-sensing elements, the multiple second working light-sensing elements, and the multiple third working light-sensing elements are respectively disposed in the first working area, the second working area, and the third working area. The multiple first reference light-sensing elements, the multiple second reference light-sensing elements, and the multiple third reference light-sensing elements are respectively disposed in the first reference area, the second reference area, and the third reference area.