Fingerprint Sensor Display Structure for Thermal Expansion Control
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Solution Overview
Problem
Existing display devices face structural deformation due to thermal expansion of filling members, which can compromise the integrity and functionality of components like fingerprint sensors.
Innovation Solution
Incorporating a filling member with a coefficient of thermal expansion less than twice that of a metal plate and a thickness greater than the metal plate, positioned to cover the fingerprint sensor and allow for thermal expansion, while maintaining structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a filling member with high coefficient of thermal expansion is used to fill the through hole of the metal plate, then the filling member can easily accommodate thermal expansion, but structural deformation occurs compromising the integrity of components
Solution Approach 1:
The patent changes the material parameter of the filling member by selecting a material with a coefficient of thermal expansion less than twice that of the metal plate (preferably 50 ppm or less). This parameter optimization allows the filling member to accommodate thermal expansion without causing excessive structural deformation, thus resolving the contradiction between adaptability and reliability.
Solution Approach 2:
The patent uses a composite structure where the filling member is made of a material different from the metal plate, specifically designed with controlled thermal expansion properties. This composite approach allows the filling member to work synergistically with the metal plate, accommodating thermal expansion while maintaining overall structural integrity.
2Strength
If the filling member is made thicker to cover the fingerprint sensor, then structural integrity is improved, but thermal expansion may cause more deformation
Solution Approach 1:
The patent optimizes the thickness parameter of the filling member to be greater than the thickness of the metal plate, which provides sufficient structural support and integrity. Combined with the controlled coefficient of thermal expansion, this thickness optimization ensures that the filling member can cover the fingerprint sensor while minimizing thermal expansion-induced deformation.
3Ease of manufacture
If the metal plate has a continuous structure, then manufacturing is simplified, but thermal expansion causes uniform deformation affecting component positioning
Solution Approach 1:
The patent segments the metal plate structure by creating a through hole that divides the metal plate into different regions. The filling member is then inserted into this through hole, creating a segmented composite structure. This segmentation allows differential thermal expansion in different regions, preventing uniform deformation and maintaining component positioning accuracy while still being manufacturable.
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 mitigates structural deformation, ensuring the reliability and functionality of fingerprint sensors by accommodating thermal expansion, thereby enhancing the durability of display devices.
Implementation Method 1
a coefficient of thermal expansion of the filling member has a value less than twice a coefficient of thermal expansion of the metal plate
Implementation Method 2
an ultrasonic fingerprint sensor recognizes a fingerprint by comparing incident ultrasonic waves irradiated upward from the ultrasonic fingerprint sensor with fingerprint-reflected ultrasonic waves reflected from the fingerprint
Implementation Method 3
The thickness of the filling member may be adjustable to form a resonant frequency between the incident ultrasonic waves and interface-reflected ultrasonic waves reflected at an interface between a member-sensor bonding member and the filling member
Data Source
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AI summary
A display device (10) includes a display panel (300); a metal plate (LP) and a filling member (RL) which are disposed on a lower surface of the display panel (300), are disposed on the same layer, and include different materials; and a fingerprint sensor (400) which is disposed on a lower surface of the filling member (RL) and is overlapped by the filling member (RL) in a thickness direction (DR3), wherein the metal plate (LP) includes a plurality of outlines extending in different directions in plan view, one outline of the metal plate (LP) includes a plurality of sides extending along a first direction (DR1) and a discontinuous part (LPS_CL) disposed between the sides, an open part (OP) recessed from the discontinuous part (LPS_CL) in a second direction (DR2) intersecting the first direction (DR1) is formed in the metal plate (LP), and the filling member (RL) is located in the open part (OP) in plan view.