Biomedical subjects

Hongwen Ren

Publications and source records attributed to Hongwen Ren.

3 recordsLinked to original sources

PubMed2005

Polymer-based flexible microlens arrays with hermaphroditic focusing properties.

Polymer microlens arrays with hermaphroditic focusing behaviors are demonstrated. Each microlens in an arrays exhibits either converging or diverging focus, depending on the polarization direction of the incident light. A polymer film with patterned microlens arrays is flexible, lightweight, and ultrathin (approximately 50 microm). Details of the lens structure, device fabrication, and lens performance are described.

Journal Article↗

PubMed2005

Hermaphroditic liquid-crystal microlens.

We demonstrate a flat microlens that exhibits hermaphroditic focusing properties. When the input polarization is parallel (perpendicular) to the liquid-crystal directors, the lens exhibits a positive (negative) focal length. To select the proper polarization, we could rotate the polarizer (or the lens) mechanically or by use of an electrically controlled twisted nematic liquid-crystal cell. Details of the lens structure and of the device's fabrication and performance are described.

Journal Article↗

PubMed2004

Liquid-crystal microlens arrays using patterned polymer networks.

A real-time dynamically tunable-focus microlens array made from a polymer-liquid-crystal (LC) composite is demonstrated. The polymer was first patterned in microlens array cavities by lamination, and the LC-monomer mixture was then injected to the molded polymer cavities and finally stabilized by UV light-induced networks. Using this new fabrication method, we demonstrated a lens with a spherical shape and a glazed surface. This LC-based microlens can reach approximately 100% light efficiency for linearly polarized light. The saturation voltage of the lens is approximately 60 Vrms, and the response time is approximately 30 ms.

Journal Article↗