Glass Sealing Material Layer for Laser Bonding
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Solution Overview
Problem
Existing glass substrate sealing methods using laser irradiation often result in cracks and fractures due to thermal stress, compromising the reliability and sealing properties of electronic devices.
Innovation Solution
A glass member with a sealing material layer containing low-expansion filler particles and a laser absorbent, where the filler particles are sized between 0.5 to 1 times the thickness of the sealing layer in a volume ratio of 0.1 to 50%, is used to form a melt-bonded sealing layer between glass substrates, reducing thermal stress and preventing cracks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If laser sealing is applied to seal the space between glass substrates, then thermal influences on the electronic element portion are suppressed, but cracks and fractures are likely to form on the glass substrate at the time of sealing
Solution Approach 1:
The patent changes the physical parameters of the sealing material by incorporating low-expansion filler particles with specific size distributions (0.1-50% volume ratio, 0.5-1.0 times the sealing layer thickness) to reduce thermal expansion coefficient. This parameter modification allows the sealing material to withstand laser-induced thermal stress without causing cracks in the glass substrate, thus resolving the contradiction between achieving reliable sealing and maintaining substrate integrity.
Solution Approach 2:
The patent creates a composite sealing material by combining glass material for sealing with low-expansion filler particles (such as zirconium phosphate, cordierite, or mullite) and laser absorbent. This composite structure provides both the sealing functionality and the low thermal expansion properties needed to prevent cracks during laser sealing, effectively resolving the contradiction between sealing reliability and substrate strength.
2Ease of manufacture
If a layer of glass material for sealing containing laser absorbent is irradiated with laser light to heat and melt for sealing, then sealing can be conducted without conventional heating furnace, but cracks and fractures are likely to form at the laser light irradiation completion point
Solution Approach 1:
The patent modifies the thermal and mechanical parameters of the sealing material by incorporating low-expansion filler particles with controlled size distribution. This changes the material's response to laser heating, reducing thermal stress accumulation at the irradiation completion point where the laser beam returns to the starting position, thereby preventing cracks while maintaining the efficiency of laser sealing process.
Solution Approach 2:
The low-expansion filler particles act as an intermediary component within the sealing material that absorbs and distributes the thermal stress generated during laser irradiation. These particles prevent stress concentration that would otherwise lead to cracks at the irradiation completion point, enabling reliable laser sealing without compromising substrate integrity.
3Ease of manufacture
If soda lime glass with high thermal expansion coefficient is used for glass substrate, then ease of manufacture is improved, but cracks and fractures are likely to form at the time of laser sealing
Solution Approach 1:
The patent changes the thermal expansion parameter of the sealing material by incorporating low-expansion filler particles (zirconium phosphate, cordierite, or mullite) with specific size distributions. This creates a sealing material with reduced thermal expansion coefficient that can be used with high thermal expansion glass substrates like soda lime glass without causing cracks during laser sealing, thus resolving the contradiction between ease of manufacture and thermal stress resistance.
Solution Approach 2:
The patent creates a composite sealing material that combines glass frit with low-expansion filler particles and laser absorbent. This composite structure compensates for the high thermal expansion of soda lime glass substrates, allowing the use of easily manufactured glass substrates while preventing thermal stress cracks during laser sealing through the low-expansion properties of the filler particles.
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 approach effectively suppresses cracks and fractures in the glass substrates during laser sealing, enhancing the sealing properties and reliability of electronic devices while maintaining hermetic sealing.
Implementation Method 1
a low-expansion filler comprising low-expansion filler particles... wherein the glass material for sealing contains no low-expansion filler particles having particle sizes exceeding the thickness T of the sealing material layer
Implementation Method 2
irradiated with a laser light to heat and melt the layer thereby to conduct sealing
Implementation Method 3
a sealing layer comprising a melt-bonded layer of a glass material for sealing
Data Source
AI summary
The invention seeks to increase the sealing property and the reliability of an electronic device by suppressing cracks, fractures and the like of a glass substrate at the time of laser sealing. A glass substrate 3 has a sealing region. On the sealing region, a sealing material layer 5 comprising a glass material for sealing containing a low-expansion filler and a laser absorbent is provided. The glass material for sealing contains no low-expansion filler particles having particle sizes exceeding the thickness T of the sealing material layer 5 and contains low-expansion filler particles having particle sizes within a range of from 0.5T to 1T based on the thickness T of the sealing material layer 5 in a volume ratio of from 0.1 to 50%. Such a glass substrate 3 and a glass substrate 2 having an element-formed region provided with an electronic element are laminated, and the sealing material layer 5 is irradiated with a laser light 6 and melted to bond the glass substrates 2 and 3.