Forming spacers in situ by photolithography to mechanically stabilize electrofluidic-based switchable optical elements

M. Wang, Yuanyuan Guo, R.A. Hayes, D. Liu, D.J. Broer, G. Zhou

Research output: Contribution to journalArticleAcademicpeer-review

8 Citations (Scopus)
283 Downloads (Pure)

Abstract

Electro-Fluidic Displays (EFD) have been demonstrated to be an attractive technology for incorporation into portable display devices. EFDs have excellent optical efficiency and fast switching enabling video content. Ensuring mechanical stability of EFD display cells is a key challenge and essential for developing large area as well as flexible displays. Although the electro-optic performance of an EFD, unlike a liquid crystal display (LCD), is insensitive to cell-gap, extreme changes in cell-gap can result in irreversible collapse of the cell. Here we use photolithography to develop spacers to prevent cell-gap collapse and provide the required mechanical stability for EFD devices. The spacer is formed directly on the cover plates (ITO/glass) after cell assembly with UV light induced phase separation polymerization in the illuminated area. Phase separation behavior between polar aqueous solution and polymer is closely related to the solubility of acrylate monomers. In this work, polyethylene glycol diacrylate (PEGDA) as cross-linker, 2-hydroxyethyl acrylate (HEA) and acrylic acid or acrylamide as co-monomers are investigated for fabricating the spacers. PEGDA was added to the mixtures in order to increase the mechanical strength of the spacer. The spacers showed excellent performance for cell-gap control in EFD devices.

Original languageEnglish
Article number250
JournalMaterials
Volume9
Issue number4
DOIs
Publication statusPublished - 2016

Fingerprint

Photolithography
Optical devices
Fluidics
Display devices
Mechanical stability
Phase separation
Polyethylene glycols
Monomers
Flexible displays
ITO glass
Acrylamide
Electrooptical effects
Liquid crystal displays
Ultraviolet radiation
Acrylics
Strength of materials
Polymers
Solubility
Polymerization
Acids

Keywords

  • Electrofluidic display
  • Electrowetting
  • Mechanical stability
  • Phase separation
  • Photopolymerization
  • Spacer

Cite this

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title = "Forming spacers in situ by photolithography to mechanically stabilize electrofluidic-based switchable optical elements",
abstract = "Electro-Fluidic Displays (EFD) have been demonstrated to be an attractive technology for incorporation into portable display devices. EFDs have excellent optical efficiency and fast switching enabling video content. Ensuring mechanical stability of EFD display cells is a key challenge and essential for developing large area as well as flexible displays. Although the electro-optic performance of an EFD, unlike a liquid crystal display (LCD), is insensitive to cell-gap, extreme changes in cell-gap can result in irreversible collapse of the cell. Here we use photolithography to develop spacers to prevent cell-gap collapse and provide the required mechanical stability for EFD devices. The spacer is formed directly on the cover plates (ITO/glass) after cell assembly with UV light induced phase separation polymerization in the illuminated area. Phase separation behavior between polar aqueous solution and polymer is closely related to the solubility of acrylate monomers. In this work, polyethylene glycol diacrylate (PEGDA) as cross-linker, 2-hydroxyethyl acrylate (HEA) and acrylic acid or acrylamide as co-monomers are investigated for fabricating the spacers. PEGDA was added to the mixtures in order to increase the mechanical strength of the spacer. The spacers showed excellent performance for cell-gap control in EFD devices.",
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Forming spacers in situ by photolithography to mechanically stabilize electrofluidic-based switchable optical elements. / Wang, M.; Guo, Yuanyuan; Hayes, R.A.; Liu, D.; Broer, D.J.; Zhou, G.

In: Materials, Vol. 9, No. 4, 250, 2016.

Research output: Contribution to journalArticleAcademicpeer-review

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AU - Zhou, G.

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