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resource guide fixed focal length telecentric liquid lens / specialty filters / accessories microscopy / objectives cameras illumination targets
Electrostatic Pressure
Window
OFF
Water Oil Optical Axis
Window
Metal Metal
Insulation
Electrostatic Pressure
Window
ON
Oil Optical Axis
Window
Metal Metal
Insulation
Figure 7.2: Diagram illustrating the working principle of the Corning®
Varioptic® Liquid Lens.
Figure 7.3: Diagram illustrating the working principle of the Optotune
Electrically Focus-Tunable Liquid Lenses.
The adaptability, speed, and versatility of liquid lenses make them
ideal for a variety of machine vision, life science, and measuring and
inspection applications. Due to their traditional mechanical layout,
standard machine vision lenses struggle to capture sharp and accurate
images in high-speed or precise applications that require quick
refocusing.
Machine Vision
High-volume assembly lines require fast, accurate, and precise
throughput. Integrating a liquid lens into an inspection system is an
optimal, compact, and economical solution when focusing at multiple
distances is required. Liquid lenses are an ideal solution for barcode
inspection, package sorting, quality control, and rapid automation.
Life Sciences
Liquid lenses improve and simplify the process of focus stacking
(“z-stacking”) in microscopy imaging applications. Focus stacking is
often required when imaging with high-magnifi cation objectives due to
their limited DOFs. A liquid lens can quickly and precisely focus to various
object planes, therefore speeding up focus stacking. Liquid lenses
can be easily integrated into tube lenses or in infi nity space within
a microscope. Liquid lenses are often used in ophthalmology, where
refraction control and DOF adjustment is crucial. Standard ophthalmic
equipment contains multiple glass lenses used to adjust for the human
eye. These lenses can be replaced with a single liquid lens, speeding
up the imaging or diagnosis process and decreasing the overall size of
ophthalmic equipment such as OCTs and phoropters.
Unmanned Aerial Vehicles
By adding a liquid lens to an unmanned aerial vehicle (UAV) imaging
system, image sharpness is quickly maintained across various heights.
Liquid lenses are especially advantageous in agricultural inspection
and monitoring, geographic information systems, and in surveillance
applications.
Measurement and Dimensional Rendering
When paired with a distance sensor and camera, a liquid lens can
quickly image diff erent planes of a 3D object. The images are then
stitched together in software to create an accurate three-dimensional
rendering.
Section 7.3: Liquid Lens Applications
Section 7.4: Liquid Lens Technology
Corning® Varioptic® Variable Focus
Liquid Lens Technology
Variable focus liquid lenses focus using a process called electrowetting,
which is the application of electric fi elds to manipulate the wetting
properties, and therefore shape and curvature, of a liquid. The
liquid lens cell contains two immiscible liquids: a non-conductive oil
and a water solution separated by an interface as shown in Figure 7,2.
Applying a voltage at the interface between the two liquids changes
the curvature, and therefore focal length, of the lens within tens of
milliseconds. Applying more voltage increases the overall curvature
and optical power of the liquid lens.
The variable focus liquid lenses’ capacitive characteristics allows
for stable operation in high-temperature environments once a thermal
equilibrium is achieved. In addition, the two liquids within the
lens have the same density, making the system insensitive to vibration
and shock.
Variable focus liquid lenses can be diffi cult to work with, as their
small size makes them challenging to use with existing objectives.
They are best suited integrated into optical designs, where their size
is less of a limiting factor.
Optotune Electrically Focus-Tunable Lenses
Optotune Electrically Focus-Tunable Lenses consist of an optical fl uidfi
lled container sealed with a polymer membrane. A current-driven actuator
exerts pressure on the membrane, causing the curvature of the
lens (and therefore the optical power) to change. Due to their current
dependency, electrically-focused tunable lenses function with low operating
voltages and focus within milliseconds. These lenses do not alter
polarization, have high laser damage threshold, and introduce minimal
aberrations
Membrane
Actuator with Voice Coil
Container
Fluid
Actuator with Voice Coil
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