50/60-Hz Lighting Flicker
50/60-Hz Lighting Flicker: Alternating current (AC) powered light sources such as incandescent or fluorescent lighting have variations in light output. This variation — or flicker — can cause an ALS to trigger when it’s not supposed to, resulting in unwanted variations in light measurements. The integrated analog to digital converter (ADC) in ams digital ALS devices serve to filter out optical noise, such as 50/60-Hz lighting flicker, through high-resolution sampling.
Color Temperature: A digital ALS system can also include color sensors with color filters that will read the red, green, and blue components of the visible light spectrum. A system with this ability can be used to measure the color temperature of the light source — fluorescent or incandescent — to further optimize the picture display quality. This feature can help improve image quality by maintaining a correct white color balance under changing lighting conditions, automatically and without any intervention from the user.
For HDTVs using RGB LEDs for backlighting, LED aging can cause the white point for the entire backlight to shift over time. Color sensors provide an automatic feedback mechanism that can maintain the white point at the original factory settings for the life of the set. To accelerate time-to-market and simplify design-in effort, support for device drivers and/or C-reference code is available from ams.
ams recently announced the availability of technology that enables a 42” flat panel TV to use less than 60 watts of power, while delivering an optimal viewing experience. An off-the-shelf television can be enhanced with ams’ Digital Ambient Light Sensor technology and smart LED drivers. The result is a TV that uses up to 50% percent less energy than standard 42” models – exceeding Energy Star 6.0 guidelines – while providing the highest picture quality, even in the lowest light conditions.
There is a significant environmental benefit as well. Based on the average daily television viewing in the United States, adopting ams’s intelligent sensor-driven backlighting technology would result in a reduction in CO2 consumption equivalent to removing more than 1 million cars from the road.
A study by the Consumer Electronics Association showed that when it comes to TVs, two items at the top of consumers’ wish lists are a low-power HDTV, and better picture quality. Yet with new Energy Star Guidelines being introduced in the spring of 2013, delivering both items on the wish list will become more challenging. Energy Star 6.0 calls for a 42” TV set to consume just 62.9 watts of power, and the maximum any TV can consume – regardless of size – is just 85 watts. Additionally, the measurement of power usage will cover four levels of ambient room light, as most consumers prefer to watch television in living rooms with low light levels.
2013 televisions that combine an ams Digital Ambient Light Sensor with local dimming and high-accuracy drivers will meet and exceed the Energy Star 6.0 ratings without waivers or unusable brightness settings, while delivering a higher quality viewing experience. The ams Digital Ambient Light Sensor does this by sensing the ambient light level of the room and adapting the backlight to a lower power level. The impact of this is threefold: 1) the TV has improved contrast ratio, which is noticeable and pleasing to the eye; 2) there is no blinding or discomfort to the consumer by the “excessively bright displays, and 3) substantial power savings is realized due to automatically adjusted lower backlight drive based on ambient light conditions.
Large LCD display LED backlighting block diagram
More information about ams can be found at ams website