PTC Device Insulating Members for Burr Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Downsizing PTC devices for surface-mount applications poses challenges in reducing thickness while maintaining structural integrity and avoiding burr or flash issues during cutting, which affects manufacturing yield and subsequent processes like tape and reel, SMT mounting, and soldering.
Innovation Solution
A PTC device with insulating members at corners connecting to adjacent lateral surfaces, comprising a laminated structure of electrically conductive and PTC material layers with insulating layers, and electrode layers, where the insulating members are made of prepreg or resin with higher hardness and glass transition temperature than the PTC material, enhancing structural strength and preventing burr formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the PTC device is downsized to form factor 0201 to reduce space occupation, then the device thickness can be reduced, but the structural strength becomes insufficient and burr/flash issues occur during cutting
Solution Approach 1:
The patent applies composite materials by combining the PTC material layer with insulating layers having different mechanical properties. The insulating layers with higher glass transition temperatures provide enhanced structural strength and rigidity to the thin device, preventing deformation and burr formation during cutting while maintaining the required thin profile for 0201 form factor
Solution Approach 2:
The patent changes the thermal and mechanical parameters of the insulating layers by selecting materials with glass transition temperatures at least 50°C higher than the PTC material. This parameter change ensures the insulating layers remain dimensionally stable during high-temperature cutting processes, preventing burr and flash formation while supporting the thin device structure
2Volume of moving object
If the device thickness is reduced to meet 0201 specification, then space is saved, but burr and flash occur during cutting affecting manufacturing yield
Solution Approach 1:
The patent changes the thermal parameters of the insulating layers by selecting materials with glass transition temperatures at least 50°C higher than the PTC material. This ensures the insulating layers remain dimensionally stable during high-temperature cutting processes, preventing burr and flash formation and maintaining cutting precision for thin devices
Solution Approach 2:
The patent applies local quality by using insulating layers with different thermal and mechanical properties at specific locations (where burr formation occurs during cutting). These localized insulating structures provide thermal stability and mechanical support precisely where needed during the cutting process, preventing burr and flash without affecting the overall device thickness
3Volume of moving object
If insulating layers are removed to reduce thickness, then device thickness decreases, but the PTC device may flaw due to insufficient strength during manufacturing
Solution Approach 1:
The patent uses composite materials by combining the PTC material layer with insulating layers that have higher glass transition temperatures. This composite structure provides the necessary structural strength and dimensional stability for manufacturing reliability while maintaining a thin overall device thickness suitable for 0201 form factor
Solution Approach 2:
The patent changes the thermal parameters of the insulating layers by selecting materials with glass transition temperatures at least 50°C higher than the PTC material. This parameter change ensures the insulating layers remain dimensionally stable during high-temperature manufacturing processes, preventing device flaws and maintaining reliability in thin devices
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 reduces burr and flash issues, improves manufacturing yield, and ensures reliable tape, reel, and soldering processes, making the PTC device suitable for small form factors like 0201 without compromising thickness or symmetry.
Implementation Method 1
the insulating members are made of prepreg or resin with higher hardness and glass transition temperature than the PTC material
Implementation Method 2
The resistive material has PTC feature, i.e., it has an low resistance at a normal temperature; however, when an over-current or an over-temperature occurs in the circuit, the resistance instantaneously increases to extremely high resistance
Data Source
AI summary
A PTC device comprises a current and temperature sensing element, a first insulating layer, a second insulating layer, a first electrode layer and a second electrode layer. The current and temperature sensing device is a laminated structure comprising a first conductive layer, a second conductive layer and a PTC material layer. The first and second conductive layers are disposed on first and second surfaces of the PTC material layer, respectively. The second surface is opposite to the first surface. The first and second insulating layers are disposed on the first and second conductive layers, respectively. The first electrode layer is disposed on the first insulating layer and electrically connects to the first conductive layer. The second electrode layer is disposed on the second insulating layer and electrically connects to the second conductive layer. Corners of the current and temperature sensing device are provided with insulating members.