White Photosensitive Resin Spacer for High-Resolution Reflectivity
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Solution Overview
Problem
Current white photoresists face challenges in achieving high resolution, heat-resistant reflectivity, and ink repellency, leading to poor brightness and color performance in light-emitting devices due to the limitations of traditional pigment-based methods.
Innovation Solution
A white photosensitive resin composition comprising a polymerizable compound with ethylenically-unsaturated monomers and thiol compounds, a fluorine-containing ethylenically-unsaturated monomer, an alkali-soluble resin, and a photopolymerization initiator, along with a white pigment, which forms a spacer with improved resolution, heat-resistant reflectivity, and ink repellency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If more white pigments are used to increase reflectivity, then light utilization and brightness are improved, but reactivity of the photoresist is reduced and pattern resolution deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters of the photoresist by introducing a thiol compound with specific molecular structure (formula I-2) and controlling its content within 1-50 parts by weight per 100 parts by weight of white pigment. This parameter optimization allows the photoresist to maintain high reactivity for precise patterning while tolerating high white pigment content for reflectivity
Solution Approach 2:
The patent creates a composite photoresist system combining white pigment particles with a matrix containing thiol compound, ethylenically unsaturated monomer, and photopolymerization initiator. This composite structure allows the thiol compound to act as a coupling agent between pigment particles and polymer matrix, maintaining both optical properties and chemical reactivity simultaneously
2Manufacturing precision
If more white photoresist or highly reactive materials are used to improve resolution, then pattern precision is improved, but whiteness and reflectivity are reduced due to yellowing
Solution Approach 1:
The patent optimizes the ratio parameters between key components: white pigment content (10-80 parts by weight per 100 parts by weight of polymerizable compound), thiol compound content (1-50 parts by weight per 100 parts by weight of white pigment), and photopolymerization initiator content (1-20 parts by weight per 100 parts by weight of polymerizable compound). This balanced parameter set achieves both high resolution and high reflectivity without yellowing
Solution Approach 2:
The patent employs a thiol compound with specific molecular structure that acts as a temporary reactive component during the photopolymerization process. This compound enables high reactivity for precise patterning but is consumed during curing, leaving a stable, non-yellowing final product that maintains high reflectivity
3Ease of manufacture
If traditional pigment dispersion method is used to form color light filter, then manufacturing process is established, but transmission efficiency of backlight source is reduced and brightness requirement cannot be met
Solution Approach 1:
The patent extracts and removes the traditional colorant (pigment or dye) from the photoresist composition, replacing it with a white photoresist system. This extraction eliminates the light-absorbing colorants that reduce backlight transmission while maintaining the manufacturing process framework of coating, exposure, and development
Solution Approach 2:
Instead of using colored pigments to create color filters, the patent inverts the approach by using a white, highly reflective photoresist that does not absorb light. The color filtering function is achieved through the physical structure and quantum dot layers rather than through pigment absorption, thereby maximizing backlight transmission efficiency
4Ease of operation
If black matrix is used as spacer, then ink repellency is provided for inkjet printing, but quantum dot light conversion layer cannot emit light efficiently and brightness is reduced
Solution Approach 1:
The patent creates a white spacer material that simultaneously provides multiple functions: (1) ink repellency for inkjet printing through surface properties, (2) high light reflectivity to enhance quantum dot emission efficiency, and (3) spacer function for structural support. This multi-functional design eliminates the need for separate black matrix layer
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 composition enables high-resolution, heat-resistant, and ink-repellent spacers that enhance light utilization and brightness in light-emitting devices, improving color purity and reducing yellowing issues.
Implementation Method 1
a photopolymerization initiator (C)
Implementation Method 2
the white photoresist needs to not let a yellowing phenomenon occur to a panel at a high temperature of 250° C., and a high-precision pattern is more difficult to be achieved in miniaturization and at an opening, and residue also readily occurs
Data Source
AI summary
A white photosensitive resin composition, a white spacer, a light conversion layer, and a light-emitting device are provided. The white photosensitive resin composition includes a polymerizable compound (A), an alkali-soluble resin (B), a photopolymerization initiator (C), a solvent (D), and a white pigment (E). The polymerizable compound (A) includes an ethylenically-unsaturated monomer (A-1) represented by formula (I-1) and a thiol compound (A-2) having two or more thiol groups in one molecule, wherein based on 100 mass % of the polymerizable compound (A), a total content of the ethylenically-unsaturated monomer (A-1) and the thiol compound (A-2) is 10 mass % to 98 mass %.