New colour sensor for display-equipped devices such as smartphones and tablets

06-02-2015 | ROHM Semiconductor | New Technologies

Capable of detecting the colour temperature, brightness, and RGB components
of ambient light - a new colour sensor for display-equipped devices such as
smartphones and tablets has been developed by Rohm.

The BH1745NUC exploits original infrared removal technology and computing
methods to achieve the industry's highest infrared cut-off characteristics,
reducing the effects of infrared rays by over 10x compared with conventional
products. This enables compatibility with dark (low permeability) optical
windows - unlike conventional colour sensors that cannot provide accurate
detection due to the effects of infrared interference when dark windows are
used, says the company.

In recent years a greater number of smartphones, tablets, and other
display-equipped devices have begun to integrate colour sensors in order to
analyze the RGB components of ambient light for display image adjustment or
perform backlight dimming based on the surrounding brightness levels.

Conventional colour sensors require a transparent optical window in order to
accurately detect visible (i.e. RGB) light. However, the design trend in
many smartphones and portable devices is to adopt dark optical windows,
which although are more stylish make it difficult to precisely detect
colours, since less visible light gets through and the light that does
permeate gets mixed in with IR rays.
In response, ROHM takes advantage of optical sensor expertise cultivated
over many years, including original infrared removal technology and
proprietary computing methods, to develop a colour sensor that provides
unmatched performance - even with dark optical windows.

Compatibility with dark optical windows provides greater design flexibility
- Industry-leading infrared cut-off characteristics reduce the effects of IR
rays by more than 10x compared with conventional products. This provides
greater design freedom by enabling support for even dark optical windows.
ROHM's new colour sensor is capable of filtering only the spectrum of
visible light in order to perform more accurate brightness and colour
temperature calculations based on ambient conditions.

Applications include display-equipped devices such as smartphones and
tablets where the device analyzes the RGB components of ambient light and
detects the colour temperature for adjusting display images, or detects the
brightness for optimized LED backlight dimming in displays based on
surrounding conditions. It also targets industrial equipment and processing
facilities that detect the colour of products and/or liquids.

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