Fingerprint Sensor Integration in Stacked Display Panels
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Solution Overview
Problem
Existing electronic apparatuses face challenges in integrating a fingerprint sensing unit effectively into a display panel, particularly in terms of structural compatibility and reliability, due to differences in thickness and adhesive stress between the sensing circuit board and the display panel components.
Innovation Solution
The electronic apparatus incorporates a lower panel with stacked sheets, including a cushion layer, a heat dissipation layer, and a light blocking layer, with openings of varying sizes to accommodate the fingerprint sensor and sensing circuit board, ensuring equal or reduced thickness and stable adhesive coupling, minimizing stress and enhancing coupling strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the fingerprint sensing unit is integrated into the display panel with stacked sheets, then the fingerprint sensing function is achieved, but the thickness difference between the sensing circuit board and display panel components causes structural incompatibility
Solution Approach 1:
The patent changes the thickness parameter of the lower panel by designing selective openings in the stacked sheets (TFT substrate, color filter substrate, and polarizer) with different areas. This creates an exposed area where the lower panel thickness is reduced to be equal to or less than the fingerprint sensing unit thickness, resolving the thickness compatibility issue while maintaining the fingerprint sensing function
Solution Approach 2:
The patent introduces a vertical dimension solution by creating openings at different positions and areas in the stacked sheets. The opening in the TFT substrate has a smaller area than the opening in the color filter substrate, which in turn has a smaller area than the opening in the polarizer. This dimensional variation allows the sensing circuit board to contact the TFT substrate in the exposed area, achieving structural compatibility
2Strength
If adhesive is applied to bond the sensing circuit board to the display panel, then coupling is achieved, but adhesive stress causes reliability issues due to thickness differences
Solution Approach 1:
The patent changes the geometric parameters of the adhesive application area by defining a specific adhesive area that corresponds to the exposed area of the lower panel. The adhesive is applied only in this exposed area where the sensing circuit board contacts the TFT substrate, rather than across the entire bonding surface. This reduces the total adhesive volume and minimizes adhesive stress while maintaining sufficient coupling strength
Solution Approach 2:
The patent applies adhesive only in the local exposed area where the sensing circuit board contacts the TFT substrate, rather than uniformly across the entire bonding surface. This localized adhesive application concentrates the bonding function where needed while reducing overall adhesive stress and improving reliability
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 the reliability and effectiveness of the fingerprint sensing function by stabilizing the sensing circuit board and sensor, reducing stress and enhancing adhesive strength, thereby improving the overall fingerprint sensing performance.
Implementation Method 1
a first sheet comprising a first functional layer having a cushion function
Implementation Method 2
a second sheet comprising a second functional layer disposed on the first adhesive layer and having a heat dissipation function
Implementation Method 3
a third sheet comprising a third functional layer disposed on the second adhesive layer and having a light blocking function
Implementation Method 4
a first adhesive layer disposed on the first functional layer, a second adhesive layer disposed on the second functional layer, and a third adhesive layer disposed on the third functional layer
Data Source
AI summary
An electronic apparatus includes a display panel including a front surface and a rear surface opposite to the front surface. A lower panel includes a plurality of sheets stacked on the rear surface of the display panel and an opening penetrating the sheets. The opening exposes a portion of a rear surface of a first sheet that has a front surface opposite to the exposed portion of the rear surface that contacts the display panel. A fingerprint sensing unit includes a fingerprint sensor positioned in the opening and a sensing circuit board connected to the fingerprint sensor. The exposed portion of the rear surface of the first sheet contacts a portion of the sensing circuit board.