Mobile phone, tablet, wearable new wind Direction: Rohm high-precision optical pulse sensor

In 2017, when the industry was excited about the big opportunities for the upcoming IoT industry, Gartner's latest survey poured a splash of cold water: Consumers were initially attracted by the novelty and appearance of wearables, However, nearly one-third of users are bored after a period of time and then abandon them, the smart watch deprecation rate of 29%, fitness class wearable device deprecation rate of 30%.

In addition to wearable devices, smartphones and tablets are also entering a lackluster innovation. According to GARTNER,2016 's year-round smartphone sales volume of 1.5 billion, an increase of 5% from 2015, although Apple in two years later to regain the world's leading smartphone manufacturers, but in the fourth quarter of 2016 and Samsung Sales gap is the smallest in history, indicating that the cell phone differentiation is rapidly shrinking, The tablet doesn't even have to be mentioned.

With smart hardware such as wearables, smartphones and tablets entering the innovation dilemma, a new differentiated innovation is quietly emerging, which is the low-power, high-precision optical pulse sensor. From electrical signals to physiological signals, a new value space for smart hardware is being opened.

Unique optical pulse-BO sensor

Rohm Roma Semiconductor is a well-known global semiconductor manufacturer, since its inception in Japan in 1958 after half a century of development has become a global system IC and leading semiconductor manufacturers, products involved in IC, discrete components, optical components, passive components, modules, Semiconductor application products and medical devices.

February 21, 2017, Rohm Roma Semiconductor in Beijing launched the latest research and production of optical pulse sensor BH1790GLC. Pulse refers to the volume of blood vessels that occur with the heart output, Rohm Semiconductor (Shanghai) Co., Ltd. Design Center senior engineer Structural said, BH1790GLC is mainly used by the green light to reach the human blood vessel after scattering back results: When the blood flow in the blood, The intensity of the reflected green light will become smaller, when the blood rheology is small, the intensity of the green light will become larger, the final appearance is a pulse signal, through the number of pulses can calculate the body's pulse number.

Previously there were infrared pulse sensors, but it is difficult to adapt to outdoor and other disturbing light intensity scenes. Using the Rohm sensor technology advantage, the BH1790GLC uses a green light wavelength led photodiode that is ideal for pulse detection, while the photosensitive part uses a green light filter and infrared (IR) cutoff filter to combine the Pulse sensor's proprietary filter structure, enabling high-precision detection Moreover, the effect of infrared radiation is reduced to less than 1/10 of the previous products, even in the intense motion and sunlight and other strong infrared interference environment, can also obtain stable pulse data.

Structural stressed that in the outdoor detection of pulse, often lead to poor detection accuracy. This is because the solar spectrum is a complex spectrum, in addition to visible light as well as ultraviolet and infrared light, infrared light can also penetrate the human body, which will be superimposed on a noise, it is very difficult to calculate the number of pulses. To solve this problem, Rohm used a special infrared removal measure, adding two layers of filter: One is an infrared filter, one is a color filter. Infrared filter can be the outside of the infrared light all filtered out, color filter can be visible in addition to the green light in all of the filter out, only let green light through, so that highlights the green light, to achieve high-precision detection.

Another advantage of the BH1790GLC is low power consumption. The power consumption of the pulse sensor mainly comes from two aspects, one is the driving current of the LED, the other is the power consumption inside the chip. Because BH1790GLC products can achieve high-precision detection, so driving LED lights do not need a strong current, this part of the current can be cut off. The BH1790GLC interior also optimizes the circuit construction, which uses a capacitive integral amplifier instead of the traditional transimpedance amplifier, and reduces the current consumption. Structural says the overall power consumption of BH1790GLC has fallen by about 74% from previous products, enabling the industry's lowest-level low power consumption and helping to extend the battery life of wearable devices.

In addition, because the pulse sensor is most used in sports watches, mobile bracelet and other products, in outdoor sports often with the human body to produce relative motion and noise, Rohm developed a special pulse calculation algorithm for this situation. The method uses the accelerometer and pulse sensor of the Kionix company of Rohm Group to collect the signal simultaneously, and then through the fast Fourier transform in the frequency domain to find the pulse noise consistent with the acceleration sensor signal frequency, remove it and restore the pure pulse signal. By testing, the BH1790GLC is always consistent with the test results of the standard test instrument under high-speed motion.

BH1790GLC's advantages also include the use of low-brightness, low VF voltage LED components, no longer need the previous led power supply with the DCDC circuit, compared with previous products can reduce the installation area of up to 30%, help to reduce the design load.

A variety of algorithms and development platforms for developers

Between June 2016 and August, Gartner surveyed more than 9,500 consumers from Australia, the UK and the United States, investigating their attitudes to wearables and buying behavior. Surveys show that consumers discard wearables because they lack practicality or lack of bright spots, and people under the age of 45 are more likely to use smartphones to solve everything they need.

Obviously the advent of the BH1790GLC optical pulse sensor is a boon for wearable devices, tablets and smartphones, and can be used to compete for practicality and differentiation. Although BH1790GLC is known as an optical pulse sensor, pulse-based measurements can be used to calculate more valuable data. Measurement of the maximum oxygen uptake is a measure of a person's aerobic exercise level commonly used methods, a more intuitive method is in the human movement when using special instruments to collect exhaled gas, and then analyzed with a gas analyzer, the cost of this measurement is high and complex; another relatively simple method is based on the maximum oxygen uptake and the human pulse number of the mathematical relationship , using the pulse number to deduce the maximum oxygen uptake of the human body.

Other potential applications of BH1790GLC include a pulse sensor placed underneath the game console to monitor the user's heartbeat while playing the game console, giving some kind of feedback signal in the game, which can also be achieved with a pulse sensor. Rohm is also developing a new algorithm that uses the body's pulse count to calculate the body's blood pressure. In some intelligent software, it is also possible to reflect a person's current mental state by the number of pulses. Developers can develop their own algorithms according to their own needs, and further enrich BH1790GLC's application scenarios.

In recent years, more and more developers in the industry to use the Arduino open platform, can be very convenient to do software development and product evaluation. Rohm has been selling sensor evaluation kits on the official website since 2016 10, an evaluation kit that supports the Arduino open platform. The Rohm sensor expansion Board is fully compatible with the Arduino UNO Development Board, which can be plugged into a variety of Roma sensors, and now has a pulse sensor expansion board, which can be purchased on the official website from February 2017 onwards.

BH1790GLC has started selling samples in October 2016 (600 yen/per: excluding tax), and in November 2016 it began to produce 500,000 of the monthly output, and the production base of the prior process was Rohm Apollo Co., Ltd. (Japan Fukuoka County), the production base of the latter process is Rohm Electronics Philippines Inc. (Philippines).

Differentiated smart devices and end markets

BH1790GLC the advent of optical pulse sensors for wearable devices, as well as smart phones, tablets and other intelligent terminal market, what will be the possible changes?

ROHM Co., Ltd. LSI Commodity Development Headquarters Sensing Solutions LSI Commodity Development Department of sensor development manager Mountain Bank letter, the original pulse sensor is only used in the professional medical field, with the public awareness of health management continues to improve, now also continue to popularize to smart watches, sports bracelet, Rohm also introduced the corresponding products. The wearable device market is the first step in the Rohm, followed by a variety of vital signs, including in-vehicle monitoring of the human pulse.

Mountain Bank letter said, although there have been many companies have introduced similar consumer products, but in general, in terms of accuracy, power consumption and so on, not fully meet the medical level requirements. Mountain Bank believes that BH1790GLC in the standard heart rate band detection and other aspects are close to medical-grade applications, Rohm mainly want to make a difference in high-end applications. In addition to the detection of pulse, including blood pressure measurement, mental state, etc. can bring higher accuracy and faster speed.

ROHM Co., Ltd. LSI Commodity Development Headquarters Sensing Solutions LSI Commodity Development Department Sensor Development Course Technical Investigation director Sagara Takeshi said that for various reasons, the current market for personal wearable devices to meet a certain bottleneck, but in terms of health concepts should also generate more demand, including pension, Hospital auxiliary Care, insurance, employee health management, Rohm more value these long-term market. For example, the insurance company wants to carry on the health management to the insured user, the factory wants to carry on the health management to the staff, all is the latent application scenario.

Of course, this is a huge market especially for the health management of the elderly. According to the 2015-year report of the group, China from 2001 to 2020 is the rapid aging phase, the average annual increase of 5.96 million elderly population, the annual growth rate of 3.28%, to 2020 the elderly population will reach 248 million, aging level will reach 17.17%. Among them, 80 years of age and above will reach 30.67 million people, accounting for 12.37% of the elderly population. The expanding old age market has created a huge imagination for optical pulse sensors.

It is worth mentioning that BH1790GLC is actually a combination of the group of three companies Rohm. In addition to Rohm Roma Semiconductors, the Rohm group also has Kionix company and Lambi Semiconductor (Lapis Semiconductor). Kionix is a well-known U.S. semiconductor company acquired by Roma in 2009, with the world's leading capacitive MEMS development technology as well as accelerometers, gyroscope sensors and associated product portfolios. Lambi Semiconductor, formerly known as Oki Semiconductor in Japan, was acquired by Rohm in 2008, including low-power MCUs, speech synthesis chips, wireless communication modules, and more.

The advent of BH1790GLC shows that with the advances in sensor technology, wearable smart devices and smart terminal markets still have innovative and imaginative spaces, which provide new ideas and new directions for entrepreneurs and big companies to innovate. (Wen/Ningchuang, the era of cloud technology)

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Mobile phone, tablet, wearable new wind Direction: Rohm high-precision optical pulse sensor