If you can remember, some decades back, taking high-quality photographs required one to own an expensive high-standard camera with very expensive lenses. As if it wasn’t enough, the operator required to have some advanced skills and know-how of how to focus and re-focus the camera in case the subject moved. However, following a rise in demand for automation technology in various enterprises globally, the liquid lenses technology was born and has gained popularity ever since. But, what is liquid lens technology and how has it impacted the business world today?
Now, although noticeable improvements have been made in the digital camera world, the shape and focal length of your lens still remain unchanged. That’s the main reason why professional photographers still carry multiple lenses with different focal lengths to capture objects close or far away.
So, to save on time and at the same time improve image clarity, a modernized technology such as the liquid lens technology had to be adopted.
Liquid Lens Technology: An Ultimate Guide
What is Liquid Lens Technology?
Now, liquid lens technology is rapidly gaining popularity in recent times due to its dynamics, speed and high efficiency. This technology uses liquid lenses that change their shapes and sizes whenever current or voltage is applied. The liquid lenses used are kind of small cells that are sealed with water and oil in a process called electrowetting.
When current is applied, the oil inside is forced to change its shape into a convex/concave lens very quickly (in a matter of milliseconds). This continuous rapid change in the shape of the electrically conductive fluid is what allows the lenses to achieve fast autofocusing regardless of whether the objects being focused on are small or far away from the lens.
Since there are no moving mechanical parts in these lenses, the lenses are hence resistant to shocks and vibration making them durable, flexible and usable in a wide range of applications simultaneously.
For instance, this technology can be used in the form of machine vision in pharmaceutical companies to inspect different types of drugs. It can also be used in digital photography, industrial data capture, barcode reading and biometric data acquisition among others.
To get deeper into this technology, there are two types of liquid lenses, which are transmissive, and reflective lenses.
- Reflective Liquid Lenses:
This is a technology used in reflector telescopes instead of using traditional mirror lenses. Here, a container containing liquid, most preferably mercury, is rotated at a high-speed using centripetal force to form a kind of a smooth reflective concavity that forms a lens perfect for telescope applications.
- Transmissive Liquid Lenses:
Now, while reflective liquid lenses use one fluid, transmissive liquid lenses use two immiscible fluids with different refractive indexes (more about this later) to create a lens. This technology is by the way what we will be covering in this topic.
Just as we defined it earlier, two fluids, one electrically conductive while the other is a non-conducting oil, are contained in a tube with two transparent ends. When the surface of the tube and the electrically conductive fluid are charged with DC voltage, the fluid (most preferable water) expands thus changing its shape into a concave or convex shape.
Since the change in current is applied rapidly, the shape of the lens too can change very fast to meet the required applications. Now, since the boundary of these two fluids is extremely smooth, these lenses have a very high optical quality that can capture small images as small as 10 microns.
How do Liquid Lenses Work?
From what we’ve already discussed, I believe you’re now acquitted with how liquid lens technology works. To polish it further, we will use a simple demonstration that will clear the air to everyone.
Now, let’s take an example of a drop of water placed on top of a hydrophobic surface (a surface that repels water). Obviously, the drop of water will react by forming a bead since its being repelled by the hydrophobic surface.
Supposing the hydrophobic surface is resting on top of an aluminum surface then an electric current is passed on the water droplet and the aluminum surface. In that case, the water will get electrostatically attracted to the aluminum surface forcing its molecules to spread out in a bid to penetrate the hydrophobic barrier.
This effect will cause the water molecules to change shape in a process called electrowetting. So, to manipulate how the water gets electrostatically attracted to the aluminum surface, you’ll only need to increase or decrease the voltage.
In the process, the water will be forced to take many shapes. Now, if this water droplet was to be used as a lens, then the rate by which it changes its shape will act as the different focal lengths.
Applying this Principle to Camera Lenses
So, to apply this technology in camera lenses, a shape-shifting liquid can be used alongside another liquid that would repel it (such as water and oil). The two liquids are then placed inside a lens and supported on either side with glass. The body of the lens is then covered with a conductive metal which again is coated with a hydrophobic insulator.
Now, when current is applied, the shape-shifting liquid is repelled on all sides including the hydrophobic surface of the lens and the repellent liquid inside forcing it to change its shape rapidly including defying the laws of gravity. This rapid change in shape is what this technology is all about.
Why Use This Technology?
Now that we’ve discussed everything that revolves around the liquid lens technology, some people might begin to wonder why exactly scientists had to go through all these troubles just to form this technology. Although we’ve seen how fast and responsive the technology is as compared to traditional mechanical lenses, do they really pose any benefits in today’s business enterprises? Well, in this section, we will dive into some of the benefits of this technology as well as discuss why it’s the backbone in these specific areas.
- Offers Multiple Focal Lengths:
This is by far one of the major advantages of investing in this technology. By using this technology, the Depth of Field (DOF) is totally handled as the lenses can electronically adjust themselves to create multiple focal lengths without having to adjust them mechanically.
Doing the same with a traditional lens will require you to either use a motorized zoom lens or else, you’ll have to physically reposition the object being focused by bringing it closer or taking it further away.
An alternative way to increase the DOF in traditional lenses would be to increase the focal length by reducing the aperture size. One drawback with this approach, however, is that the amount of light getting through would be reduced thus affecting the clarity of the object being focused.
- Rapid Change in Focus and Focal Length:
Another reason why liquid lens technology is so paramount is the rate by which it changes focus and focal length. Now, if you were using a mechanical lens, changing the focus and focal length will require you to adjust the rings on the outside of the lens.
After zooming, you have to wait for the motors to adjust the image to make it clear. With liquid lens technology, this process is accomplished in an impressive super-fast speed of just a few milliseconds. The best thing about it is that the liquid lens is capable of generating a clear focus on objects that are several distances away. Not only that, it can also generate well-focused images of objects that are of totally different sizes.
- No Mechanical Parts Involved:
If you happen to drop a traditional mechanical lens, the result is that it’s likely to get damaged, and in some cases, irreversible damage. The reason for this is because there are too many mechanical parts inside the lens that are too fragile to get damaged.
But, with a liquid lens, these problems have totally been taken care of as there are no moving or mechanical parts inside them. In fact, most of these lenses are built with shock-resisting capability just to boost their longevity.
- Quality Image Stabilization:
In the world of photography, avid photographers usually use cumbersome tripods to support their cameras when taking photos. Now, no matter how hard you try to steady your hands, traditional cameras still pick those handshakes causing the image to appear blurry.
Thankfully, with liquid lenses, this challenge is easily counterbalanced as it’s able to deliver a sharp clear image despite your hands shaking. So, with this technology, tripods are absolutely obsolete as these lenses can still deliver the best despite numerous human errors.
- Much Smaller:
Now, if you happen to observe most of the large lenses that dominate the world of photography today, most of them have retracting lenses that stick way out of the camera in an attempt to focus a zoomed image. Although they do keep the job done, the problem is the amount of bulk they add to your package.
However, with liquid lenses, this is a problem of the past as they use totally different technology to zoom in and out when changing the focal length. Since there are no moving parts, this makes them small and very compact.
- Energy Efficiency:
Another reason why this technology is so special is the fact that its energy efficient. You see, with liquid lenses, the amount of energy required to change the focal length is much lower as compared to what a mechanical lens would need to stick the lens in and out of the camera.
- Improved Lifespan:
We all know that mechanical parts are prone to wear and tear especially after they approach their maximum number of cycles. In the case of industrial-based lenses that handle a variety of heavy-duty tasks, their life expectancy is definitely shorter.
So, to improve their lifespan and reduce the rate by which they wear out, most companies use liquid lenses instead to take advantage of their longer lifespan. Since they don’t have any mechanical parts, these lenses can handle heavy-duty tasks as they can perform millions of cycles without wearing out.
- Close Focusing:
With traditional lenses, focusing objects that are too close without altering the quality of the image is very difficult. However, with liquid lenses, this is just like taking a walk in the pack. All thanks to the electrowetting technology, these lenses can focus objects that are at extremely close distances without altering the quality of the image.
Due to this huge milestone, these lenses can now be applied in a variety of fields such as in medicine where fiber optic cables are inserted in the human body to check the cause of a problem.
Now, What is Refractive Index?
Earlier on in this article, we mentioned something to do with refractive index. In the world of liquid lenses, this phrase is not new and it’s actually a very important topic that defines how efficient a lens constructed from the electrowetting technology can perform.
But, what is refractive index? In a simple definition, this is the measure of how light propagates in a material. It can also be defined as the measure of how light bends when passing through one medium to another.
According to research, the higher the refractive index is, the slower the light rays travel through the medium. Now, most people are wondering what the relationship between the refractive index and lenses really is. Now, when it comes to lenses, the refractive index is what determines the focal length.
Therefore, if a lens has a high refractive index, it means light rays are slower leading to a shorter focal length. On the other hand, if the index of refraction is lower, then the light rays move faster meaning the focal length is longer.
If a lens has a high refraction index, then it means it bends light more than a lens with a lower refractive index. Another fact about lenses is that the smaller the profile a lens has (the thinner the lens is), the more it’s able to refract or bend light.
Applications of Liquid Lenses
Earlier on in this article, we mentioned a couple of benefits of liquid lenses. Due to these advantages alongside others such as versatility, flexibility and incredibly fast focus time, this technology gained access in industrial applications making it the backbone of most industrial processes from machine vision, 3-D imagery to inspection application. So, for this and much more, here are some real-life applications of liquid lens technology.
- Machine Vision
One of the most common applications of liquid lenses is in machine vision. Here, high-volume assembly lines require this type of technology to meet their daily threshold. Due to the fast, accurate and precise throughput of this technology, these lenses are used in inspection systems to inspect objects at varying distances.
For instance, in barcode inspection and packaging sorting, industries take advantage of how fast these lenses focus and refocus objects at varying distances with unmatched accuracy.
Machine vision technology is also used by pharmaceutical companies to inspect a wide variety of drugs. It allows them to inspect drugs with varying sizes from capsules to pills without having to stop production just to adjust the depth of focus.
- Medical Field
Due to their close focusing ability, liquid lenses have also made their way in the medical arena where they’re used on Laparoscopic cameras to focus on very close images. Due to their huge advantage, these cameras can now be inserted inside the human body for treatment purposes or to check the cause of a problem just before an operation.
- 3-D Image Rendering
Another field where liquid lens technology is applied is in the 3-dimensional world. Here, a liquid lens is combined with a distance sensor and a camera to capture a sequence of images in a technique known as focus stacking. These images are then merged together in a transparent environment to create a 3-dimensional rendering that can be used for analysis.
- Unmanned Aerial Vehicles
Liquid lenses can also be used in unmanned vehicles such as drones and other surveillance equipment to spy and pick critical intelligence data. Their ability to pick sharp images at varying heights is one major characteristic that allows them to suit this application. Other than being used in the military, they can also be used for agricultural inspection and geographic information systems.
- In Smartphones
Our list can never be declared over without mentioning the Smartphone world. We all use Smartphones, right? Now, one characteristic of today’s Smartphone is that they’re becoming slimmer and slimmer. The most interesting thing about it is how their cameras are getting even stronger. Since their lenses cannot zoom out, lenses such as the ones Verioptic make have been added in this equation to make the modern Smartphone slim yet very powerful in terms of camera quality.
In conclusion, it’s clear that liquid lens technology has totally taken the center stage in the industrial sector. Due to major improvements made in this technology, these lenses have in fact exploded in popularity making them the best choice in a wide range of applications.
As the technology strives to achieve greater milestones in the near future, companies such as Verioptic have offered to make even smaller cameras that will be available right at our doorsteps in form of Smartphone cameras and USB liquid lenses that can be used by civilians.