Optical Sensor Device With Filter Layer Between Microlenses And Sensor
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Solution Overview
Problem
Optical fingerprint collection devices face challenges in reducing size while maintaining satisfactory sensing quality due to the limitations imposed by optical lenses and image sensing chips.
Innovation Solution
An optical sensor device is designed with a sensor layer, a microlens layer, and a filter layer, where the filter layer is positioned between the sensor and microlens layers to filter multi-wavelength light, generating different wavelengths and reducing interference, and an aperture layer is included to transmit these filtered lights to the sensor layer, allowing for a compact design with good sensing quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical lenses and image sensing chips are used for fingerprint collection, then sensing quality can be maintained, but device size and thickness increase
Solution Approach 1:
The optical system is segmented into multiple functional layers: microlens layer for light collection, filter layer for wavelength selection, and sensor layer for detection. Each layer performs a specific function, allowing the system to maintain sensing quality while reducing overall complexity and size compared to traditional lens-chip configurations
Solution Approach 2:
The patent transitions from a traditional three-dimensional optical path requiring large object and image distances to a planar layered structure where light propagation occurs primarily in the vertical dimension. This dimensional reorganization allows compact integration while preserving optical functionality
2Length of stationary object
If the object distance and image distance are reduced to minimize device thickness, then device compactness improves, but optical imaging quality deteriorates
Solution Approach 1:
Each layer in the optical sensor device is optimized for its specific function: microlenses are designed with specific curvature and material properties for efficient light collection at minimal distances, filters are positioned and sized to optimize wavelength separation, and sensor elements are configured for maximum detection efficiency. This localized optimization allows high imaging quality in a compact thickness
Solution Approach 2:
The optical system employs composite structures combining different materials with complementary properties: transparent materials for light transmission, selective filter materials for wavelength discrimination, and photosensitive materials for detection. This composite approach enables effective optical imaging within reduced thickness constraints
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 enables a small-sized optical sensor device capable of providing excellent sensing quality by reducing background interference and optimizing the focusing of multi-wavelength light, thereby enhancing the fingerprint sensing process.
Implementation Method 1
Each of the microlenses focuses the multi-wavelength light on a corresponding one of the sensor areas
Implementation Method 2
The filter layer is disposed between the sensor layer and the microlens layer, and configured to filter the multi-wavelength light to generate a plurality of lights with different wavelengths
Data Source
AI summary
The optical sensor device including a sensor layer, a microlens layer and a filter layer is provided. The sensor layer includes a plurality of sensor areas, and is configured to sense a multi-wavelength light from a finger. The microlens layer includes a plurality of microlenses arranged in an array, and is disposed on the sensor layer. Each of the microlenses focuses the multi-wavelength light on a corresponding one of the sensor areas. The filter layer is disposed between the sensor layer and the microlens layer, and configured to filter the multi-wavelength light to generate a plurality of lights with different wavelengths. In addition, the fingerprint sensor apparatus including the foregoing optical sensor device is also provided.