New Brightness (Color) Sensor Optimized for Smartphones

Industry-leading infrared cutoff function provides greater enclosure design flexibility

Kyoto, Japan and Santa Clara, Calif. – June 27, 2017 – ROHM Semiconductor has recently announced the availability of a color sensor for display-equipped devices such as smartphones and tablets capable of detecting the color temperature, brightness, and RGB components of ambient light.


The BH1747NUC leverages original infrared removal technology and computing methods to achieve the industry's highest* infrared cutoff 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 color sensors that cannot provide accurate detection due to the effects of infrared interference when dark windows are used.

In recent years a greater number of smartphones, tablets, and other display-equipped devices have begun to integrate color 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 color 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 colors, 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 color sensor that provides unmatched performance and high sensitivity (4x higher than even ROHM's BH1745NUC) – to support even darker optical windows (down to 1% transmissivity).

*ROHM study as of June 27, 2017

Improved Enclosure Design
Color Spectral Sensititvity Characteristics

Availability: Now (Sample) /January 2018 (OEM)

Key Features

- Industry-leading infrared cutoff characteristics reduce the effects of IR rays by more than 10x compared with conventional products
- 4x higher sensitivity supports even darker optical windows (even 1% illuminance transmissivity)


1) Display-equipped devices such as smartphones and tablets

  • Analyzes the RGB components of ambient light and detects the color temperature for adjusting display images
  • Detects the brightness for optimized LED backlight dimming in displays based on surrounding conditions
2) Industrial equipment and processing facilities that detect the color of products and/or liquids


Color Temperature Detection Comparison
Brightness Detection Comparison