Take an Insight into Liquid Lens Technology-Dynamic Auto-Focusing System

One of the keys in all applications of machine vision and code-reading is to select the correct optical lens. Some essential factors require to be taken into consideration, such as Field of View (FOV), aperture, compatibility of sensor chip dimension as well as focus. After installation, the focus will be very difficult to be adjusted if the working distance of the barcode reader changes all of a sudden. Then you may wonder what defines a good optical lens and how brilliant performance it can demonstrate. Here is the answer: A fine optical lens facilitates machine vision distinguishing a great variety of codes in a millisecond and empowers the device to detect nuanced defects. Say industrial code-readers are equipped with such a pair of "intelligent eyes", what it will be like?

Advancement: A new type of lens came out

From pin-hole imaging experiment as long as 2400 years ago to the appearance of crescent lens in 1812, optical lens technology witnessed constant development along with human beings' dedicated pursuit of prime imaging quality.

As we all know, the optical lens is composed of prime lens and zoom lens with regard to its capability to adjust focal length. Prime lens usually comprises several fixed-focus lens, traditionally glass lens and fixed shape. The shape is fixed even after being assembled into a lens so as to maintain  the same flexion toward ray of light. Therefore, the focal length is fixed. In accord with the Gaussian lens formula 1/f=1/u+1/v ( f stands for focal length, u is object distance, v is image distance), when the distance from a shot object to the lens changes while it is focusing, image distance will change as focal length (f) is fixed. That is to say, the skew of best focus takes place. Then image plane needs to be moved in order to fit the best focus, which is what we usually call as focusing. It shares the same principle as employing a barcoder reader with fixed focus: you have to move the object to realize reading.

Zoom lens is a kind of lens that can switch its focal length and is equipped with various focal distance. It can achieve the best focus without adjusting the position of lens itself mechanically. Then, here comes a question: Why don't we all use zoom lens? In fact, compared with prime lens, conventional zoom lens not only costs more, but also tends to be larger in size and relatively complicated in craftsmanship.

So are there any other solutions that we can have one device that is both with outstanding performance and satisfactory pricing? Yes, a new type of lens came out-liquid lens.

Liquid lens technology-Auto-focusing in a millisecond

Liquid lens is small, mechanically or electrically controlled cell containing optical-grade liquid. Made up of a prime lens and another special material, it resembles human eyes, which can quickly adjust focus to accommodate objects located at various working distance (WD). So it is such a perfect solution for imaging application that requires rapid focusing, high throughput, and depth of field (DOF) and WD accommodation. Liquid lens generally consists of gradient refractive lens, fluid-filled lens and electrowetting lens. Let's take electrowetting for example, most of which is comprised of two immiscible, optically defect-free liquids in a tightly sealed container. According to the principle of electrowetting, the interface shape between two liquids is going to change when a current or voltage is applied to a cell, just like the crystalline lens of human eyes changing curvature in order to realize convergence and divergence of light. Therefore, liquid lens can locate the best focus without moving image plane and achieve auto-focusing. Compared with traditional prime lens and zoom lens, liquid lens enables faster focusing in a matter of milliseconds so as to level up productivity, which is extremely ideal for a fast-paced and high-efficient working place. What's more, it also features large working distance scope, quicker system installation, remote focus control and a long lifetime.

Smartmore: VS800 with liquid lens technology

As a brilliant startup with great ambition and strong scientific research capability, Smartmore has always been trying hard to optimize the performance of products and make it the best. SMore ViScanner VS800 is a compact code reader independently developed by SmartMore. SMore VS800 employs optimization algorithm and is equipped with a liquid lens, which can achieve millisecond-level high-speed focusing automatically. It has powerful and easy-to-use features, such as rapid focusing, flexible working distance, small in size and easy to install. VS800 can be widely applied in 3C electronics, lithium-ion battery, automobile manufacturing, food/drug packaging industry. Some features are highlighted as follows:

Acute and accurate auto focus technology

SMore VS800 liquid lens comes from cube-A technology (acute & accurate auto-focus) self-developed by SmartMore, supporting focusing in a matter of milliseconds. Compared with traditional mechanical lens focusing technology which requires hundreds of sample images for focusing, SMore VS800 only needs a few sample images for acute focusing. The sampling speed has been improved by nearly a hundred times, and it has strong advantage of rapid, accurate and clear focusing. 

One-key parameter adjustment

For dark and bright scenarios, focusing, exposure, gain, light source adjustment and symbology search functions are automatically completed, and parameters can be automatically adjusted. Even non-professionals can operate it quickly, greatly saving debugging time. 

Small in size and easy to mount

SMore VS800 is small in size, up to 47 mm*25 mm*43 mm, and does not take much space. Embedded with 4 LED light sources and 2 green dot sights, the reader can quickly locate the code. The reader is only half size of a business card.

Flexible working distance

SMore VS800 supports a flexible working distance of 40 mm to 300 mm, covering mainstream code-reading object distance applications on market. Equipped with the 6 mm liquid lens, users can be provided with flexible code reading applications.

For more information, please visit our website: https://inside.smartmore.com/