ST's presence in the iPhone7 is fuelling speculation that similar time-of-flight (ToF) sensors are designed into the Apple iPhone7S and iPhone8 which are expected to launch in September and October of 2017, and helping to drive business optimism at ST for the second half of 2017 (ST raises capex for "major product ramp"). As is normal with suppliers to Apple, ST is not commenting except to say that demand for a number of products has driven its increased capex in 2017 and strong revenue expectations for the second half of 2017.

Such ToF sensors can be used for auto-ranging for cameras as well as 3D imaging, proximity sensing, ambient light sensing and gesture recognition. And ToF also has application in Lidar.

ST has been investigating the technology for some time and its development of single photon avalanche diode (SPAD) has been fundamental to this. ST provides several smartphone manufacturers with ToF ranging sensors, according to System Plus Consulting. However, in its tear down report it points out that within the iPhone 7 Plus the custom FlightSense device is a die measuring 2.80 mm by 2.40 mm, half the size of the rest of STMicroelectronics’s FlightSense portfolio.

The sensor is located above the main speaker and uses optical land grid array packaging. There are improvements in the integration of the source, the vertical cavity surface-emitting laser, on the sensing/processing die along with a new design of SPAD-based detector.

"This could be the first step for STMicroelectronics proving the feasibility of small form-factor ToF devices which could then be part of the more ambitious 3D-sensing camera of the Apple iPhone 8," said Stephane Elisabeth, an analyst at System Plus Consulting.

Such speculations are not diminished by reports in 2016 that Apple built a cleanroom in Grenoble to develop image sensor technology and reports in 2014 that Apple had been working with STMicroelectronics at the Minatec campus in Grenoble.