Transfer Substrate Light-Absorbing Layer for Clean Phosphor Lift-Off
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Solution Overview
Problem
The manufacturing process for micro LED displays faces challenges such as deformation of phosphor surfaces during transfer, non-adherence of phosphors to transfer substrates, and damage to wiring substrates during laser lift-off, which complicates the production of large-sized displays.
Innovation Solution
A transfer substrate with a temporary substrate, unit phosphor structures, a phosphor binder, a color filter, and an inorganic light absorbing layer is used, along with a protective layer and metal films to prevent deformation and adherence issues, and a method involving a light absorbing layer with an amorphous crystal structure to facilitate separation and prevent re-adherence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If phosphor is transferred onto semiconductor light emitting element, then color display is achieved, but phosphor surface deformation occurs and phosphor re-adheres to transfer substrate
Solution Approach 1:
A release layer is introduced as an intermediary between the phosphor and the transfer substrate. This release layer facilitates the transfer process while preventing the phosphor from re-adhering to the transfer substrate, thereby maintaining phosphor surface stability during transfer operations
Solution Approach 2:
The surface energy parameters of the transfer substrate are modified through coating treatments to create optimal transfer conditions. By adjusting adhesion parameters, the substrate allows controlled phosphor release without causing surface deformation or re-adherence
2Productivity
If laser lift-off process is used to separate phosphor from transfer substrate, then phosphor transfer is achieved, but wiring substrate is damaged
Solution Approach 1:
The release layer serves as a mediator that absorbs the laser energy during lift-off, protecting the wiring substrate from direct laser exposure and thermal damage while enabling complete phosphor transfer to the target substrate
Solution Approach 2:
The laser energy that could potentially damage the wiring substrate is converted into a beneficial effect by the release layer, which uses the laser energy to facilitate clean separation of the phosphor while protecting underlying structures from thermal damage
3Manufacturing precision
If multiple phosphor structures are disposed on temporary substrate, then color filter alignment is improved, but manufacturing complexity increases
Solution Approach 1:
The temporary substrate is divided into multiple regions with individually optimized phosphor structures and color filters. Each segment can be independently aligned and transferred, simplifying the overall manufacturing process while maintaining high precision color alignment
Solution Approach 2:
The temporary substrate is designed with multi-functional capabilities to support various phosphor structures and color filter configurations simultaneously, enabling complex color display requirements to be met without proportionally increasing manufacturing complexity
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 prevents phosphor re-adherence and damage to substrates, enhancing the transfer process and reducing manufacturing complexities, thereby improving the efficiency and reliability of micro LED display production.
Implementation Method 1
a light absorbing layer including an inorganic layer disposed between the temporary substrate and the color filter, for absorbing light to separate the unit phosphor structure from the temporary substrate
Implementation Method 2
the light absorbing layer may have an amorphous crystal structure variable by absorbing light
Data Source
AI summary
The present invention is applicable to a technical field related to display apparatuses, and the present invention relates to a transfer substrate that transfers a phosphor onto a semiconductor light-emitting device, in which the transfer substrate may comprise: a temporary substrate; a unit phosphor structure which is provided on the temporary substrate and comprises a color filter, a phosphor stacked on the color filter, and a phosphor binder for fixing the phosphor; and a light-absorption layer, which is an inorganic layer provided between the temporary substrate and the color filter, and absorbs light to separate the unit phosphor structure from the temporary substrate.