Samsung has revealed "Sensor OLED", a new display panel technology that has many tiny light sensors embedded directly into the whole OLED panel surface. This allows the panel to read fingerprints anywhere on the display, as well as check cardiovascular health. Current in-display fingerprint readers utilize a seperate sensor module under a small part of the display; this new technology is embedded directly in the display itself and covers the whole display area. When placing two fingers on the display, (one from each hand,) the display "can measure the user's heart rate, blood pressure and stress level". Samsung also showed off several new foldable phone concepts using its flexible display technology. One is called Rollable Flex, a display that unrolls like a scroll to become five times larger, essentially transforming from a slim phone to a large tablet.