Display Sensor Coupling Using Segmented Adhesives
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Electronic devices with sensors integrated into the display area face mechanical reliability issues due to adhesive films, which also deteriorate sensor performance by having low ultrasonic impedance compared to the display or sensor materials.
Innovation Solution
A display-sensor coupling structure using a thermosetting material for mechanical reliability and a UV curable adhesive to maintain sensor performance, ensuring the sensor remains attached during impacts and does not affect signal quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If an adhesive film is used to attach the sensor to the display panel, then the sensor can be securely mounted, but the adhesive material deteriorates sensor performance due to low ultrasonic impedance
Solution Approach 1:
The patent divides the adhesive system into two separate materials: a first adhesive material (thermosetting resin) for mechanical bonding between the sensor and display panel, and a second adhesive material (UV curable adhesive) for securing the sensor's inactive area. This segmentation allows each adhesive to be optimized for its specific function without compromising sensor performance in the active sensing area.
Solution Approach 2:
The patent applies different adhesive materials to different areas of the sensor based on local requirements: the first adhesive material is applied to the active area where ultrasonic signals are transmitted, while the second adhesive material is applied to the inactive area. This local differentiation ensures that the active area maintains high ultrasonic impedance for sensor performance while the inactive area provides mechanical stability.
2Reliability
If a thermosetting resin is used to attach the sensor, then mechanical reliability is improved, but the curing process may affect sensor alignment and positioning
Solution Approach 1:
The patent performs preliminary positioning of the sensor on the display panel before applying and curing the thermosetting resin. The sensor is temporarily fixed in the correct position, and then the adhesive is applied around the periphery to secure it permanently. This preliminary action ensures proper alignment is established before the adhesive sets, preventing positioning errors during the curing process.
Solution Approach 2:
The patent introduces a release film as an intermediary element during the assembly process. The release film is placed between the sensor and the display panel during alignment, allowing for easy adjustment and repositioning. Once alignment is achieved, the release film is removed and the sensor is permanently bonded with the thermosetting resin, ensuring both manufacturing precision and mechanical 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
The solution ensures the sensor remains attached during external impacts, maintaining mechanical reliability and preventing signal interference from the adhesive materials, thus enhancing overall performance.
Implementation Method 1
a UV curable adhesive is injected between inner walls of the opening and the sensor, curing the UV curable adhesive by irradiating UV light to the UV curable adhesive
Implementation Method 2
thermally curing the thermosetting resin
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
Disclosed is an electronic device that includes a housing, a display module that includes a first panel including a first surface, a second surface opposite to the first surface, and a plurality of pixels disposed between the first surface and the second surface, a cover layer that is disposed on the first surface of the first panel and that forms one surface of the housing, and a second panel disposed on the second surface of the first panel, and a sensor that is coupled to the display module and that forms a sensing area on the one surface of the housing. The display module includes an opening that is formed through the second panel and in which the sensor is disposed, and the sensor includes an active area and an inactive area formed around the active area. A first adhesive material is formed between the active area and the first panel. The first adhesive material includes a mechanical or thermal characteristic that a glass transition temperature Tg ranges from 0°C to 25°C in a frequency condition of 0.01 Hz to 0.1 Hz, a modulus of elasticity at 35°C or more is 0.2 GPa or less, and a modulus of elasticity at - 10°C or less is 1 GPa or more.