Transparent Laser Weld Regions for Hermetic Glass Sealing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for hermetic sealing of glass substrates, such as frit-based sealants and laser welding, often result in opaque seals that are detrimental for light-transmitting applications due to high temperatures and poor quality hermeticity, which is particularly problematic for devices like OLEDs that require absolute transparency and ambient temperature sealing.
Innovation Solution
The use of thin, low melting glass or ultraviolet absorbing films during laser welding to create a transparent and hermetic seal by absorbing incident laser wavelengths, inducing temperature-induced absorption and color center formation, allowing for low-power and low-temperature diffusion welding of glass substrates with minimal conductivity reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If frit-based sealants with negative CTE fillers are used for hermetic sealing, then thermal expansion mismatch is reduced, but the seal becomes opaque and light transmission is blocked
Solution Approach 1:
The patent removes the negative CTE inorganic fillers from the glass frit composition, extracting only the essential glass sealing material. This extraction eliminates the opacity caused by filler particles while maintaining the hermetic sealing function through the glass matrix alone.
Solution Approach 2:
The patent creates a composite glass frit formulation combining multiple glass compositions (e.g., borosilicate, aluminosilicate) to achieve both low-temperature processing and transparency. The composite glass structure provides thermal stability without requiring opaque filler particles.
2Reliability
If high-temperature processing is used to melt glass frit, then hermetic sealing is achieved, but temperature-sensitive devices like OLEDs are damaged
Solution Approach 1:
The patent modifies the glass transition temperature parameter of the sealing material by selecting specific glass compositions (e.g., borosilicate glass with Tg around 560°C, aluminosilicate with lower Tg) that enable sealing at reduced temperatures. This parameter change allows hermetic sealing at temperatures safe for OLED and other temperature-sensitive devices.
Solution Approach 2:
The patent applies the glass frit sealant to the substrate before device assembly, allowing the sealing material to be pre-positioned and then activated at low temperature during a final sealing step that does not expose the device to high temperatures.
3Strength
If conventional laser welding is used to join glass substrates, then strong bonds are formed, but the weld regions become opaque and distort light
Solution Approach 1:
The patent creates a localized weld zone with controlled geometry and composition that maintains optical clarity. By concentrating the laser energy in a precise focal region and using transparent glass compositions, the weld achieves high strength while remaining optically transparent in the visible spectrum.
Solution Approach 2:
The patent utilizes controlled melting and solidification phase transitions of transparent glass materials during laser welding. The rapid heating and cooling cycles create a localized molten zone that solidifies into a strong, transparent bond without forming opaque crystalline structures or inclusions.
4Illumination intensity
If transparent glass compositions are used for sealing, then light transmission is maintained, but processing temperatures must be precisely controlled to avoid deformation
Solution Approach 1:
The patent incorporates thermal cushioning layers or support structures that absorb and distribute excess heat, preventing localized overheating and deformation of transparent glass sealing regions. This cushioning effect simplifies temperature control by providing a thermal buffer zone.
Solution Approach 2:
The patent implements real-time monitoring of temperature and welding parameters with feedback control systems that adjust laser power, scan speed, and focal position to maintain optimal processing conditions. This feedback mechanism compensates for variations in material properties and environmental conditions, simplifying the overall control process.
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 method enables the production of strong, transparent, and hermetic seals with reduced manufacturing complexity and cost, suitable for a wide range of electronic and display devices, including OLEDs, by maintaining transparency and mechanical integrity while accommodating different thermal expansion coefficients between substrates.
Implementation Method 1
bonding the workpiece between the first and second substrates by locally heating the film with laser radiation having a predetermined wavelength
Implementation Method 2
locally heating the film with laser radiation having a predetermined wavelength
Implementation Method 3
low melting glass or ultraviolet absorbing films, is employed to create a hermetic barrier layer
Data Source
AI summary
Disclosed herein are sealed devices comprising a first substrate, a second substrate, an inorganic film between the first and second substrates, and at least one weld region comprising a bond between the first and second substrates. The weld region can comprise a chemical composition different from that of the inorganic film and the first or second substrates. The sealed devices may further comprise a stress region encompassing at least the weld region, in which a portion of the device is under a greater stress than the remaining portion of the device. Also disclosed herein are display and electronic components comprising such sealed devices.