A lab-on-phone instrument with varifocal microscope via a liquid-actuated aspheric lens (LAL)

Abstract

In this paper, we introduce a novel concept of liquid-actuated aspheric lens (LAL) with a built-in aspheric polydimethylsiloxane lens (APL) to enable the design of compact optical systems with varifocal microscopic imaging. The varifocal lens module consists of a sandwiched structures such as 3d printed syringe pump functionally serves as liquid controller. Other key components include two acrylic cylinders, a rigid separator, a APL/membrane composite (APLMC) embedded PDMS membrane. In functional operation, the fluidic controller was driven to control the pressure difference and ALPMC deformation. The focal length can be changed through the pressure difference. This is achieved by the adjustment of volume change of injected liquid such that a widely tunable focal length. The proposed LAL can transform to 3 modes: microscopic mode (APLMC only), convex-concave mode and biconcave mode. It is noticeable that LAL in the operation of microscopic mode is tunable in focus via the actuation of APLMC (focal length is from 4.3 to 2.3 mm and magnification 50X) and can rival the images quality of commercial microscopes. A new lab-on-phone device is economically feasible and functionally versatile to offer a great potential in the point of care applications.

Optofluidic lenses for 2D and 3D imaging

“…This microscope has a simple configuration, yet poor stability and slow response time due to the use of the droplet lens. Using elastomer-liquid lenses, the magnification range and stability can be significantly improved [111,112]. A magnification range from 20 × to 50 × has been demonstrated [112].…”

“…Using elastomer-liquid lenses, the magnification range and stability can be significantly improved [111,112]. A magnification range from 20 × to 50 × has been demonstrated [112].…”

Electrically Adaptive and Shape-Changeable Invertible Microlens

“…Furthermore, these lenses have other limitations such as complex external actuation parts, , a slow response time, and issues of reliability owing to the use of a compliant electrode . Even though some researchers have reported invertible microlenses, − they still have limitations such as a leakage of liquid, sagging by the gravity, and liquid sealing problem due to the usage of a liquid medium for varifocal lenses.…”