A ground-breaking development in smartphone optics looks set to spill over into machine vision and other image-related applications. Unlike the eye, conventional optical systems depend on the movement of solid lens elements to achieve focus and zoom. The eye, on the other hand, works in a different way. Its elastic lens of clear tissue changes curvature to focus on objects at different ranges. A similar principle could soon come to the aid of machine builders faced with the problem of how to mount the relatively large casings needed for the lens components in traditional optical systems. In auto-focus setups, power consumption is another area that would benefit.
The development I am referring to is called liquid lens technology and it promises to enable better, cheaper and smaller optical devices. The idea is that by changing the shape of a liquid, a water droplet for instance, we can manipulate the way it refracts light. Expanding on this, two clear non-mixable liquids can serve as a lens of variable focal length dependent on the curvature at the interface. Add the principle of ‘electrowetting’ and that curvature can be controlled by means of an electric charge. A liquid lens then is an optical system of variable focal length independent of any moving mechanical parts.
The big advantage is the reduction in physical size achieved by eliminating the need for said moving parts. In fact, liquid lenses can be up to 85% smaller than ordinary camera lenses of similar performance. A handy consequence is that the power required to focus is only a fraction of that required in a standard setup. The small size and high efficiency make this technology ideal for use in mobile battery-powered optical applications, where space and weight are crucial.
For design purposes, the lack of moving parts makes fabrication of the lens inherently robust. Considering the case of a typical industrial camera installed to scan items on a conveyor in use 24/7, the lifespan could be up to two million focus cycles before repair or replacement is required. By contrast, the liquid lens has an expected lifespan in excess of 100 million cycles. The fact that only the liquid interface must be manipulated provides the additional benefit of faster response as well.
Among the early adopters is machine vision manufacturer Cognex, which has equipped both handheld and fixed versions of its barcode readers with the technology. According to the company’s website, liquid lens technology enables the readers to adapt to changes in working distances better than older versions equipped with conventional auto-focus systems. With the liquid lens, it does not matter if the code appears nearer or farther away. Even for high-speed lines, the fast response allows the scanner to change focus from part to part quickly enough to scan all barcodes that may be present in the field of view. To learn more about the origins and benefits of this intriguing new technology see ‘Nick Denbow’s European report: Leaps in technology: implants and liquid lenses’.
Name change for Wonderware
One of the most significant company announcements this month comes from Wonderware. Following the combination of AVEVA with Schneider’s industrial software business, Wonderware Southern Africa has undergone a name change and will in future be known as IS³ (Industry Software, Solutions and Support). Pronounced ‘eye-es-cube’, the transformation makes the company the official AVEVA distributor for the sub-Saharan region.
Daily operations will continue as usual, with the supply and support of Wonderware, Citect and the rest of the Schneider Electric software portfolio. The difference being that the IS³ offering has been enhanced by the addition of the AVEVA solutions to close the gap between the operation and project sides of local manufacturing businesses. The extended solution range will allow IS³ to cover the plant’s entire asset lifecycle from design and commissioning, through to operation and maintenance, all on a single platform.
The combination of Schneider Electric’s operational expertise with AVEVA’s IIoT know-how and 3D design tools looks like a formidable partnership, we will be watching with interest. See ‘Wonderware Southern Africa undergoes name change to IS³’ for more.
Steven Meyer
Editor: SA Instrumentation & Control
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