Core-Shell Conductive Powder for Black Bus Electrodes
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Solution Overview
Problem
Plasma display panels (PDP) face challenges in achieving high blackness and low contact resistance in black bus electrodes, with existing materials like ruthenium oxides and ruthenium compounds being expensive, and the addition of conductive metals like silver leading to yellowing and loss of contrast due to diffusion during sintering.
Innovation Solution
A conductive composition for black bus electrodes is developed, featuring an inorganic powder coated with precious metals such as Ru, Rh, Pd, Os, Ir, Pt, and Au, which is added in low amounts to the black electrode, forming a core-shell structure to enhance blackness and reduce contact resistance while minimizing the use of expensive materials and preventing silver diffusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If expensive black components like ruthenium oxide are used to achieve high blackness, then the degree of blackness is improved, but material cost increases
Solution Approach 1:
The patent uses composite materials by combining inexpensive base metals (Cu, Ni, Pd, Ag) with small amounts of precious metal coatings (Ru, Rh, Pd, Os, Ir, Pt, Au) to create conductive powders that achieve high blackness at lower cost. The core-shell structure allows the base metal to provide bulk properties while the precious metal coating provides surface properties for blackness and conductivity.
Solution Approach 2:
The patent applies local quality by coating only the surface of the conductive powder particles with precious metals rather than using pure precious metals throughout. This creates a core-shell structure where the core provides mechanical strength and bulk conductivity while the shell provides surface blackness and contact resistance properties, significantly reducing material cost while maintaining performance.
2Reliability
If highly conductive metals like silver are added to reduce contact resistance, then contact resistance decreases, but yellowing occurs due to diffusion during sintering
Solution Approach 1:
The patent applies preliminary anti-action by pre-coating the silver or other conductive metal particles with a layer of precious metals (Ru, Rh, Pd, Os, Ir, Pt, Au) before the sintering process. This protective coating prevents the base metal from diffusing into the glass substrate during high-temperature sintering, thereby preventing yellowing and maintaining contrast while still allowing the silver to provide low contact resistance.
3Ease of manufacture
If copper is used as an inexpensive conductive metal, then material cost decreases, but oxidation occurs requiring reducing atmosphere sintering
Solution Approach 1:
The patent applies preliminary anti-action by coating copper particles with a protective layer of precious metals (Ru, Rh, Pd, Os, Ir, Pt, Au) before sintering. This coating prevents oxidation of the copper during the sintering process, allowing the use of simpler sintering atmospheres (including air or oxygen) while maintaining the cost advantages of using copper as the base metal.
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 achieves high blackness and low contact resistance, reducing material costs and preventing silver-induced yellowing, thereby improving the contrast and durability of PDPs.
Implementation Method 1
the Ag atoms are diffused into glass during the sintering process, and a resulting problem is yellowing of the black stripes that are formed
Implementation Method 2
Low contact resistance is also an element that is considered important as well as blackness. Because black components have higher resistance than conductive metals such as silver or copper
Data Source
AI summary
The black bus electrode of plasma display panel is formed from a conductive composition comprising a conductive powder, glass powder, organic binder, organic solvent, and black pigment, wherein the conductive powder is coated with metal selected from the group of Ru, Rh, Pd, Os, Ir, Pt and Au.