Slim proximity colour sensor module for smartphone designs

It will enable manufacturers to better optimise automatic disabling of smartphone touch screens during calls and the adjustment of screen brightness to ambient conditions for more comfortable and lower-energy smartphone use.

By using ams’s new TMD3702VC three-in-one integrated module supplied in a 1.44x2.84x0.65mm package in place of earlier modules that have a wider footprint, smartphone manufacturers can implement designs that have a thinner bezel, to give a greater ratio of display area to body size, while retaining important infrared proximity and light-sensing functions.

The module integrates an IR emitter, IR detector, four colour-sensing channels and optical filters. Sophisticated new optical packaging technology and design techniques developed by ams for the TMD3702VC have enabled it to produce class-leading performance.

The proximity sensor’s Vertical Cavity Surface Emitting Laser (VCSEL) Class 1 Eye Safe 940nm emitter is more optically efficient than the LED emitters found in competing devices. This keeps average Active mode power consumption of the 1.8V TMD3702VC to very low levels. In Sleep mode, the device draws just 0.7µA.

A new translucent mould-compound package used in the TMD3702VC provides a very wide ±48° field of view. The proximity engine features wide dynamic range, ambient light subtraction, and advanced optical crosstalk noise cancellation which dynamically eliminates both electrical and optical crosstalk producing reliable proximity detection.

The advanced optical sensor architecture of the TMD3702VC underpins the device’s accurate measurement of the Correlated Colour Temperature (CCT) of ambient light. The ambient light and colour sensing function includes four concurrent ambient light sensing channels – red, green, blue and clear – which all have a UV/IR blocking filter. Sensitivity, power consumption and noise are optimised with adjustable timing and power. The module accurately measures ambient light and enables the calculation of illuminance and colour temperature values which support a smartphone’s management of its display’s appearance.

Dave Moon, Senior Product Marketing Manager at ams, stated: “Today’s smartphone industrial design trend of maximising a display screen size by increasing its screen-to-body ratio and minimising the bezel area calls for the smallest module solution. The TMD3702VC with its ultra-small form factor facilitates this need, helping to almost eliminate the bezel on the display’s face.

“The TMD3702 helps phone designers minimise the space allocated to front-side ambient light and proximity sensing by providing them with a solution that is >60% smaller than the previous generation of products.”

The TMD3702VC is available for sampling now. Unit pricing is $1.15 in order quantities of 1,000 units.