“The AS7341 marks a breakthrough in the category of spectral sensors in a small package suitable for mounting in a mobile phone or consumer device. It is the smallest such device to offer 11 measurement channels, and also offers higher light sensitivity than any other multi-channel spectral sensor aimed at the consumer market,” says Kevin Jensen, Senior Marketing Manager in the Optical Sensors business line at ams. The new sensors mass production starting in February 2019.
- 8 optical channels distributed over the visible range
- 3 extra channels: Clear, Flicker and NIR channel
- 6 parallel ADCs for signal processing
- Ultra-low-profile package 3.1mm x 2mm x 1mm
- Unit pricing is $2.00 in quantities of 10,000 units.
- Spectral information enables highly accurate object color measurements
- Detection and rejection of environmental influences such as light sources
- Optimized channel count and signal processing for fast measurements
- Mobile phone compatible package
ams also introduces what it calls the world’s smallest integrated 1D ToF distance measurement and proximity sensing module.
The sensor use cases include presence detection, for example to trigger the operation of a facial recognition system when the user’s face is in range. The new TMF8701 sensor fits in a narrow bezel, helping smartphone manufacturers to realize widescreen phone designs that have a high display screen to body ratio.
“Smartphone manufacturers have been clear about the drawbacks of today’s 1D time-of-flight sensors: they are too large, and their performance degrades noticeably in adverse lighting conditions and when the display screen is dirty,” said Dave Moon, Senior Product Marketing Manager in the Integrated Optical Sensors business line of ams. “The TMF8701 addresses all of these concerns, providing customers with a device in a smaller footprint which also offers exceptional rejection of contamination and interference.”
- Direct ToF technology with high sensitivity SPAD detection
- Fast Time-to-Digital Converter (TDC) architecture
- Sub-nanosecond light pulse
- 0 – 10cm proximity detection and 10 – 60cm distance sensing @ 60Hz
- On-chip histogram processing
- 940nm VCSEL Class 1 Eye Safety with 21° FOI
- Sunlight on-chip rejection filter and algorithm
- Industry’s smallest modular OLGA 2.2mm x 3.6mm x 1.0 mm package
The TMF8701 separately identifies reflections from fingerprint smudge contaminations on the display screen and optical reflections from objects beyond the cover glass, such as the user’s face, maintaining reliable performance even when the sensor’s aperture is dirty.
The Class 1 Eye Safe VCSEL emitter has excellent immunity to interference from ambient light and produces accurate distance measurement in all lighting conditions: the module achieves accuracy of ±5% when measuring distance in the range 20-60cm in normal lighting conditions. Even in bright sunlight (100klux), ±5% accuracy is maintained at a range of up to 35cm.
The TMF8701 draws only 940µA in proximity sensing mode when sampling at 10Hz. Always on, it triggers the higher-power face recognition system to start up when the ToF sensor detects the presence of an object up to 60cm from the display screen. The proximity sensing capability of the device can also be used to trigger the display and face recognition system to switch off when detecting a reflective surface at a distance of 0-10cm from the screen. The accuracy of the TMF8701’s distance measurements also supports the selfie camera’s LDAF (laser detect auto-focus) function, especially in low-light conditions.
The TMF8701 sensor is in mass production now. Unit pricing is $2.60 in an order quantity of 5,000 units.
ams also releases the TCS3701, an RGB light and IR proximity sensor that can accurately measure the intensity of ambient light from behind an OLED screen. This capability supports today’s trend to maximize smartphone display area by eliminating front-facing bezels, where an ambient light/proximity sensor is typically located.
This ‘Behind OLED’ ambient light/proximity sensor enables smartphone manufacturers to achieve the highest possible ratio of display area to body size. The TCS3701 senses the addition of the ambient light passing through the display to light emitted by the display’s pixels located just above the sensor. ams has developed unique algorithms which enable accurate detection of ambient light levels without knowledge of the display pixel brightness above the sensor. Light transmission through an OLED screen is limited by its opacity, but the TCS3701’s ultra-high sensitivity to light means that it can still produce accurate light measurements in all lighting conditions.
The TCS3701 is available for sampling now. Unit pricing is $1.25 in an order quantity of 1,000 units.
“Smartphone OEMs today are striving to maximize their products’ screen-to-body ratio, reducing the bezel area as much as possible on the display’s face,” said David Moon, Senior Marketing Manager at ams. “The TCS3701 enables phone designers to take this trend to a new level, potentially eliminating the bezel entirely. This is only possible because the TCS3701 can operate behind an OLED display, a breakthrough enabled by the outstanding sensitivity of the device and by the implementation of sophisticated measurement algorithms to compensate for the optical distortion caused by the OLED display.”
- High ALS and color sensitivity
- 1024X dynamic range
- 0.18µm process technology with 1.8V I²C
- High proximity crosstalk compensation
- Companion non-predictive asynchronous algorithm
- Dark room to sunlight operation
- Reduced power consumption
- When combined with a VCSEL emitter enables operation behind OLED
- Enables ambient light measurement during display blanking periods