Fingerprint Circuit Force Touch via Optical Reflection
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Solution Overview
Problem
Existing fingerprint circuits in terminal products lack integration of force touch functionality, leading to limited design flexibility and increased manufacturing complexities, along with potential performance fluctuations due to external assembly factors.
Innovation Solution
A fingerprint circuit design that incorporates a light source and optical sensing device, positioned below a specular reflection layer, allowing for force touch control without additional peripheral components, enhancing design flexibility and stability by converting light into electrical signals for force touch implementation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If force touch function is integrated using external peripheral components, then force touch control can be implemented, but design flexibility is reduced and production complexity increases
Solution Approach 1:
The patent merges the force touch sensing function with the existing capacitive fingerprint circuit by integrating a light source and optical sensing device into the fingerprint sensor module. This combination eliminates the need for separate peripheral components, thereby improving design flexibility while reducing production complexity. The light source and optical sensing device are positioned within the fingerprint circuit structure, sharing the same substrate and assembly process.
2Reliability
If external peripheral components are used for force touch control, then force touch function can be added, but performance fluctuations occur due to assembly factors
Solution Approach 1:
By combining the force touch sensing components (light source and optical sensing device) with the fingerprint sensor into a single integrated module, the patent eliminates assembly-related performance fluctuations. The integrated design ensures fixed relative positions between components, removing variability introduced by separate assembly processes and improving force touch control stability.
Solution Approach 2:
The patent introduces a reflective layer as an intermediary element between the light source and optical sensing device. This reflective layer mediates the optical path, enabling force touch detection through light reflection changes caused by fingerprint sensor deformation. The intermediary structure allows for stable, repeatable optical interactions within the integrated module.
3Reliability
If light source and optical sensing device are integrated in fingerprint circuit, then force touch control stability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies preliminary action by pre-defining the positions of the light source and optical sensing device relative to the fingerprint sensor during the module design stage. The components are positioned at predetermined locations that optimize optical path alignment, and this positioning information is used throughout the manufacturing process to maintain consistency without requiring high-precision adjustment during assembly.
Solution Approach 2:
The integrated module design allows the fingerprint sensor structure itself to serve as the positioning reference for the light source and optical sensing device. The components are mounted on the same substrate with fixed geometric relationships, enabling self-alignment through the inherent structural features of the fingerprint sensor, thereby reducing the need for external positioning mechanisms.
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 improves design flexibility, reduces manufacturing difficulties, and enhances the stability and sensitivity of force touch control by eliminating the need for external references and minimizing assembly-induced performance fluctuations.
Implementation Method 1
The optical sensing device may be configured to convert the light emitted by the light source and reflected by the specular reflection layer into an electrical signal
Implementation Method 2
A specular reflection layer configured to reflect light may be arranged below the fingerprint circuit cover plate, and the light source, the optical sensing device and the fingerprint sensor may be positioned below the specular reflection layer
Data Source
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AI summary
Disclosed are a fingerprint circuit, and a force touch control method and device. The fingerprint circuit includes a fingerprint circuit cover plate (101), a fingerprint sensor (102), a light source (103) and an optical sensing device (104). A specular reflection layer (1011) is arranged below the fingerprint circuit cover plate (101). The light source (103), the optical sensing device (104) and the fingerprint sensor (102) are positioned below the specular reflection layer (1011). The light source (103) and the optical sensing device (104) are positioned on two sides of the fingerprint sensor (102) respectively. Light emitted by the light source (103) passes through a gap between the fingerprint sensor (102) and the fingerprint circuit cover plate (101) to irradiate the specular reflection layer (1011), and is reflected to the optical sensing device (104) through the specular reflection layer (1011). The optical sensing device (104) converts the light reflected by the specular reflection layer (1011) into an electrical signal, and the electrical signal may be configured for force touch control.