In this blog post, we’ll take a look at the principles and benefits of capacitive fingerprinting technology, and see if it’s evolving to become more accessible to everyone.
The term “one-touch” refers to simplifying something that would otherwise require multiple steps to accomplish. This concept of simplification is becoming increasingly important in the modern world. Being able to solve complex procedures or tasks with a single touch contributes to saving time and increasing efficiency in our daily lives. Especially in the fast-paced world of technology, the concept of one-touch has become a key factor in many industries and services. More and more objects and infrastructure are utilizing this concept because it saves wasted time and effort.
There are many tools that make one-touch possible, but one of the most common is fingerprint recognition. Fingerprint technology is rapidly being adopted in a variety of areas because it offers both security and convenience. From the door locks you see around you to the automated immigration screening at Incheon International Airport, fingerprint recognition technology has made one-touch realization possible, adding convenience to our lives.
However, the question arises as to whether or not everyone can enjoy this convenience. Some people with worn out fingerprints or injured fingers cannot recognize fingerprints. Surprisingly, there is a fingerprint recognition technology for such people. It’s called active capacitive fingerprinting technology. This technology goes beyond the traditional limitations and allows more people to enjoy the benefits of fingerprinting. To make it easier to understand, let’s take a look at the technology behind fingerprint sensors.
There are two main types of fingerprint sensors: optical and capacitive. For example, optical sensors are used at airport checkpoints, while capacitive sensors are used in door locks and laptops. Capacitive sensors are further divided into two types: directive capacitive and active capacitive. For example, directive capacitive sensors are used in door locks, while active capacitive sensors are used in laptops.
Optical fingerprint sensors literally shine a strong light on your finger and use the reflected image of your fingerprint. This method collects data by directly photographing the surface of the fingerprint, and its advantages are high precision and high stability. However, it is expensive and large, and since it uses the image of the finger’s surface, it can be difficult to recognize if the fingerprint is worn or scratched.
Capacitive fingerprint sensors, on the other hand, use electricity rather than light. Objects that are not electrified can store electricity, which is called capacitance, and the amount of electricity they can store is called capacitance. This is why static electricity is generated. Since the capacitance of the skin is greater than the capacitance of air, measuring this capacitance can be used to recognize fingerprints. This technology is especially good at minimizing recognition errors due to the condition of the finger.
There are two main ways to implement capacitive fingerprint sensors: direct measurement and signal measurement. Direct measurement literally measures the capacitance of the area the fingerprint touches. This has the advantage of being inexpensive and compact, but it has the disadvantage of poor recognition rates. As a result, this technology is mostly used in low-cost door locks and small electronic devices.
The signal measurement method, on the other hand, sends a signal through the finger to measure capacitance. The signal enters the finger and comes back out to the sensor, but only where your fingerprint has touched it. By measuring the signals that come out of the sensor, you can get a picture of the fingerprint. The signals that are measured are not affected by the epidermis of the finger, but by the dermis, which is the skin inside the epidermis. Unlike the epidermis, the dermis is hard to be wounded and is not affected by the environment such as dust and humidity, so it is possible to obtain a much more accurate image than optical and direct measurement sensors. Because of these features, signal measurement is widely used in applications requiring higher security.
With signal measurement fingerprint sensors, even people with worn or scratched fingerprints can enjoy the convenience of one touch. It is also highly secure because it can measure fingerprints very precisely. It is no longer possible to break security by cloning a fingerprint on a glass, as was done in the movie. To break the security of a signal-measuring fingerprint sensor, you need to place your finger directly on a high-resolution scanner and scan it precisely.
However, signal-measured fingerprint sensors also have a significant drawback: they are expensive per unit area. As a result, many companies are working to make the technology more affordable, and some are exploring new materials and design approaches that could solve the price problem. Currently, they are usually produced in a slender, elongated shape, about the width of a finger, to reduce the area. Because the sensor is so thin, it can’t read the entire fingerprint at once, so you have to swipe your finger from top to bottom to read it. Another drawback is that the process is more awkward than other methods.
Recently, there has been some good news about smartphones with area-measuring fingerprint sensors that can recognize the entire fingerprint. This is good news because it means that it has become cheap enough to be included in smartphones and can be produced in an area that can eliminate the inconvenience of the recognition process. Hopefully, the technology will improve in the future and more people will be able to enjoy the convenience of fingerprint recognition technology in more places beyond smartphones.
