Industry-Leading Optoelectronics Technology
With more than a decade of analog mixed-signal technology innovation and market leadership, Texas Advanced Optoelectronic Solutions (TAOS), Inc., designs and manufactures digital and analog color sensing solutions. TAOS products deliver increased system integration, design flexibility and functionality to a wide range of markets. TAOS leverages its expertise in optoelectronics and mixed-signal design to create products reflecting the cutting edge of intelligent optosensor technology.

TAOS is the industry pioneer in analog and digital optosensor technology and forged its leadership position into a broad product portfolio including light-to-digital (LTD), light-to-voltage (LTV) and light-to-frequency (LTF) light and color sensors, infrared (IR) proximity detection sensors, and linear array sensor solutions.

Color Perception
While different frequencies or wavelengths of light exist in nature, our sense of perceived color is uniquely human. It is based on color sensing built into our eyes and associated processing by the brain. There are three different types of “cones” in the retina, each sensitive to just a portion of the visible spectrum – roughly red, green, and blue. Much as a color display creates “yellow” by lighting red and green pixels with equal intensity, our eye-brain system perceives yellow when our red and green cones sense equal amounts reflecting off the same object.

Measuring Color
The colorimetric method of color measurement mimics human vision by utilizing silicon light sensors with filters for red, green, and blue wavelengths. Since silicon light sensors are sensitive to a wide range of visible and invisible light wavelengths, filters are used to limit sensitivity to particular colors such as for red, green, blue and for IR energy.

Infrared Blocking
Infrared energy (IR) is not visible to the human eye, but most photodiodes (the underlying light-sensitive devices within color sensing solutions) do respond to IR, and this can create erroneous color measurements. To remedy this problem, color sensing solutions may incorporate IR blocking. This filters out IR, which is abundant in outdoor sunlight and incandescent and halogen light sources.

Color Model And Color Space
A “color model” is a mathematical way to describe color. The most common are RGB (used in TVs, cameras and displays) and CMYK (used in printing). Both are based on three primary colors – much like human vision – but with RGB the colors are added, as happens when a display’s pixels are illuminated, whereas with CMYK color is subtracted, as happens when light reflects off a printed page.

The heel-shaped “chromaticity diagram” is one representation of colors perceivable by human vision. The chromaticity diagram actually compresses what should require three dimensions into two, and allows color to be represented as x-y coordinates – that’s why it’s shaped like a rounded triangle, with pure red, blue and green in each corner.

Without the sense of color, the world is simply less colorful – this is reflected in our very use of the word “color” to mean lively and exciting. Yet, perception of color can be subjective – people may disagree about whether an object is turquoise or blue, and some people are partially or completely “color blind.” In ordinary life, a difference in color perception is mostly inconsequential. However, in many industries, the ability to sense color precisely can be crucial.

Color sensors enable solutions for color discrimination, determination, and measurement in a wide variety of applications such as color feedback control in solid-state illumination and RGB backlight systems, color adjustment in printers, industrial process quality controls, portable medical diagnostic systems, and paper and product handling equipment.