Optical Sensor Under Transparent Screen With Angular Filter
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Solution Overview
Problem
Current devices integrating optical sensors under partially transparent screens face challenges in achieving optimal performance and efficiency, particularly in terms of surface area matching and light transmission, which affects the accuracy and functionality of sensors like fingerprint sensors.
Innovation Solution
The integration of a succession of layers including a transparent screen, an angular filter, an image sensor, and an optically transparent part with a low refractive index, along with protective layers, which collectively form the optical sensor module. This configuration ensures effective light transmission and sensor sensitivity, particularly for visible and near-infrared wavelengths, while maintaining the structural integrity of the screen.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an optical sensor is integrated under a partially transparent screen, then the sensor can be concealed within the display structure, but the light transmission efficiency and sensor accuracy deteriorate due to multiple interfaces and reflections
Solution Approach 1:
An angular filter layer is introduced as an intermediary between the screen and the optical sensor. This filter layer selectively transmits light at specific angles while blocking other angles, thereby reducing unwanted reflections and improving light transmission efficiency to the sensor without compromising the concealment integration.
Solution Approach 2:
The refractive index of the optical sensor and surrounding layers is optimized to match specific values that minimize optical interference and maximize light transmission. By carefully selecting and adjusting the refractive index parameters of the sensor substrate and adjacent layers, the system achieves better optical performance while maintaining the integrated structure.
2Area of stationary object
If the optical sensor occupies a large surface area under the screen, then the sensor coverage is improved, but the light transmission path becomes more complex and efficiency decreases
Solution Approach 1:
The angular filter is applied locally only in the regions where light transmission is critical, rather than uniformly across the entire sensor area. This allows the sensor to have large surface area coverage while the filter optimizes light transmission only where needed, reducing overall optical complexity and energy loss.
3Reliability
If multiple layers are added to protect the optical sensor, then the structural integrity is improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The angular filter layer is integrated directly into the existing display stack structure, merging the protection function with the existing layers rather than adding completely separate protective components. This approach maintains structural integrity while minimizing the increase in overall device complexity.
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 enhances the accuracy and functionality of optical sensors under partially transparent screens by optimizing light transmission and sensor sensitivity, ensuring effective operation while maintaining the screen's structural integrity.
Implementation Method 1
comprising an optically transparent part (24) having a refractive index lower by at least 0.1, preferably at least 0.15, compared to an optical material of the optical sensor (15), in contact with the layer (24)
Implementation Method 2
A second layer (22), arranged under the first layer (21), comprises an angular filter (ANGULAR FILTER)
Implementation Method 3
A third layer (23), arranged under the second layer (22), comprises an image sensor (IMAGE SENSOR)... sensitive to wavelengths in the visible and near infrared spectrum
Data Source
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AI summary
The invention relates to a device (20) comprising an at least partially transparent screen, an optical sensor (15) and, between the screen and the optical sensor, a layer (24) having at least one optically transparent portion with a refractive index lower by at least 0.1 than the refractive index of an optical material of the optical sensor.