Optical Fingerprint Sensor Light Source Mounting Stability
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Solution Overview
Problem
Existing optical fingerprint imaging systems face inefficiencies in light use and instability of the light source, affecting image capturing performance.
Innovation Solution
The system incorporates a mounting element to fix the light source to a lateral side or end portion of a substrate, eliminating gaps and ensuring a stable position, allowing light to enter directly into the substrate, enhancing light efficiency and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the light source is disposed close to a lateral side of the light guide plate using a conventional backlight structure, then the light can be guided to the active area, but the light use efficiency is reduced and the light source stability is poor
Solution Approach 1:
The patent merges the light source mounting structure with the sensor substrate by integrating the light source directly onto the sensor substrate surface. This eliminates the separate light guide plate and its associated mounting complexities, thereby improving both light use efficiency through direct coupling and light source stability through integrated fixed positioning structures such as recesses or adhesive bonding.
2Device complexity
If the light source is mounted without a fixed position structure, then the device complexity is reduced, but the relative movement between light source and substrate occurs affecting image capturing performance
Solution Approach 1:
The patent applies local quality by implementing fixed position structures only at specific locations where the light source contacts the substrate, rather than constraining the entire assembly. For example, recesses are formed only in the light source mounting area, or adhesive is applied only at specific bonding points, thereby providing necessary stability while minimizing overall structural complexity.
3Ease of manufacture
If gaps exist between the light source and substrate, then the mounting is simpler, but the light entry efficiency into the substrate is reduced
Solution Approach 1:
The patent applies preliminary action by pre-forming recesses in the substrate or light source structure before final assembly, or by pre-applying adhesive materials in specific patterns. This preliminary preparation ensures that when the light source is mounted, it automatically achieves optimal contact with the substrate surface, eliminating gaps for light entry while maintaining manufacturing simplicity through standardized pre-prepared 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 configuration improves light use efficiency and stability, resulting in enhanced image capturing performance by maintaining consistent light features and reducing relative movement between the light source and substrate.
Implementation Method 1
light emitted from the light source is adapted to be guided by the substrate of the sensor to the first surface of the substrate
Data Source
AI summary
An optical fingerprint imaging system and an optical assembly are provided. The optical fingerprint imaging system includes: a sensor including a substrate and a photosensitive layer, wherein the substrate has a first surface and a second surface which is opposite to and lower than the first surface, and the photosensitive layer is in contact with the first surface of the substrate; a light source disposed at a position lower than the first surface and higher than the second surface, and light emitted from the light source is adapted to be guided by the substrate of the sensor to the first surface of the substrate; and a mounting element adapted to mount the light source at a fixed position. Accordingly, the optical fingerprint imaging system has high light use efficiency and stable light source.