It is no secret Apple has been working on biometric headphones for a number of years now. Today the US Patent & Trademark Office published a series of three patent applications. Filed by the Cupertino company, they are all titled “Earbuds with Biometric Sensing.”
It is not surprising Apple has an interest in this area. Hearables are poised for strong growth over the next five years according to IDC latest quarterly survey. Their wearables market share is forecast to increase from 0.7% to 1.8% in 2021.
The ear provides a great platform for biometric measurement. It is a little know fact that earbuds, rather than watches, tend to be the most accurate heart-rate monitors on the market, outperformed only by traditional chest straps.
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The three patents are for three different pairs of headphones: an in-ear pair with an ear hook, a conventional pair of in-ears and a pair of over-ears.
The patent applications details how a photoplethysmogram (PPG) sensor could be added to the earbuds to collect biometric information. This technology, while difficult to pronounce, is based on a very simple fact: blood is red because it reflects red light and absorbs green light. PPG sensors operate by illuminating the skin with the light from a light-emitting diode (LED) to sense the rate of blood flow. This enables them to measure heart rate, temperature and VO2, the maximum rate of oxygen consumption.
The patent describes the headphones as follows.
This application relates to earbuds configured with one or more biometric sensors. At least one of the biometric sensors is configured to be pressed up against a portion of the tragus for making biometric measurements. In some embodiments, the housing of the earbud can be symmetric so that the earbud can be worn interchangeably in either a left or right ear of a user. In such an embodiment, the earbud can include a sensor and circuitry configured to determine and alter operation of the earbud in accordance to which ear the earbud is determined to be positioned within.
The heart rate sensor in Apple Watch also uses photoplethysmography. The watch uses green LED lights paired with light sensitive photodiodes to detect the amount of blood flowing through your wrist at any given moment. By flashing its LED lights hundreds of times per second, Apple Watch can calculate the number of times the heart beats each minute.
Of course, just because Apple was granted the patent, doesn’t necessarily guarantee that the product will ever see the light of day. But it is an intriguing idea in any case and it shows Apple has serious ambitions in this area.
The full patent application can be seen here.
Source: Patently Apple
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