An investigation of nonuniform deposition of field emission displays phosphors on unbiased indium-tin-oxide coated glass during electrophoresis

Abstract

Upon the deposition of field emission displays (FED) phosphors in electrophoresis, a weak and nonuniform deposition of phosphor on the unbiased neighbor indium-tin-oxide (ITO) patterns is always observed in addition to the expected thick and uniform deposition of phosphor on the biased patterns. An explanation of the origin of the nonuniform deposition is attempted by solving Laplace's equation with proper boundary conditions simulating the deposition bath used for the sample preparation. According to the solution of Laplace's equation, in the beginning, the potential distribution is such that the electric field has a parallel component from the unbiased ITOs to the biased ones in addition to the major vertical components of the electrical field. However, during the deposition, the field has the parallel component from the biased ITOs to the unbiased ones as the thickness of the deposited phosphor increases. This appears to generate the observed nonuniform deposition on the unbiased ITO patterns.