SAN FRANCISCO — After being off the tech radar in recent years, Silicon Valley-based Intersil has released a new Red, Green, and Blue (RGB) light sensor that aims to optimize screen brightness and improve resolution, battery life, and color quality for mobile device displays.
"Display consumes in excess of 40% of a phone's power budget today; improving power efficiency is a key element in optimizing devices," said Naresh Shetty, marketing manager for Intersil sensor products. "As screens get bigger, sensors and power are going to be a bigger issue with OEMs."
Intersil's new digital light sensor, dubbed ISL29125, communicates directly with a device's core processor to enable the automatic adjustment of display brightness based on changing light conditions to extend battery life, according to a release. ISL29125 runs at 70 microamps during device operation and less than half a microamp in standby, has an operating power supply range of 2.25 to 3.63V, and a variable conversion rate up to 16 bits.
"[ISL29125 provides] accurate information on light, it can tell if light is incandescent, florescent, or sunlight. The RGB sensor provides that level of control on different displays," Shetty said. "By monitoring ambient light, you can reduce or increase brightness based on room environment, thereby improving power consumption."
Intersil's new digital light sensor rejects IR in light sources allowing the device to operate in environments from sunlight to dark rooms while the integrated ADC rejects 50Hz and 60Hz flicker caused by artificial light sources. A selectable range allows the user to optimize sensitivity suitable for the specific application, the Intersil release continued.
"It's going to be very important that sensors get designed that give information to handsets to determine whether power needs to be given to display for optimization," said Gerry Purdy, chief mobility analyst with Compass Intelligence, a consulting and market research firm.
While sensors like ISL29125 will help optimize power consumption, Purdy added segmenting processes within handsets will be key for OEMs as phablets become more popular. Still, IHS iSuppli's Vinitia Jakhanwal said it's difficult to assess the total impact of RGB sensors on mobile devices.
"You may achieve good performance in one of the features, but what does it do to your device as a whole," asked Jakhanwal, mobile and immerging displays technology director at IHS. "It's not having a big impact on transmissivity, on your color. It can still support very high resolutions and provide you with power consumption savings."
Jakhanwal also questioned ISL29125's price point and power consumption compared to existing OLED solutions. Features that add a more than 10% premium but don't result in significant ASP increase cannot work, in her opinion.
At 1.65 mm x 1.65 mm x 0.75 mm, ISL29125's small form factor minimizes the size of the hole required to allow sufficient light through for accurate color measurement, improving overall industrial design. While it's unlikely that the sensor will be integrated into SOCs, Intersil's Shetty said the smaller geometry will be advantageous in future handset design.
Shetty also said the sensor can be integrated into camera modules to eliminate lag time during automatic white balancing. According to the company, ISL29125 could be integrated into a TV display to adjust display brightness and color consistency as the lighting conditions in a room changes.
The ISL29125 RGB sensor can be added to several applications for color temperature measurement accuracy, such as industrial color printers, thermostat displays and water quality testing devices, the release continued.
ISL29125 is currently in mass production and sensor-enabled camera solutions will be available in the second half of 2014. Shetty said he believes RGBs will achieve 35% of sensor volume by 2016 and replace existing ambient light sensor functions.
— Jessica Lipsky, Associate Editor, EE Times