Even folks who aren’t lighting wonks know that traditional LCDs have an array of color filters: red, green, and blue (RGB). These filters correspond with a matching liquid crystal cell, which turns on or off to let light through. As these RGB filters are switched on and off in front of a white backlight, viewers see an image on the display.
For television screens and other monitors, the rate at which these filters refresh is now up to over 360 times per second, which is why most of us don’t perceive this refresh rate at all as we use our devices each day.
But these layered color filters aren’t the only way to build a display.
Field-sequential color (FSC) displays don’t rely on RGB color filters. Instead of using a uniform white backlight, FSC displays, also known as color sequential displays, pulse between three backlight colors very quickly to create an image.
While FSCs require a high refresh rate, the benefits of opting for a color sequential display can be tremendous for outdoor displays and in applications where battery life is absolutely critical.
The Benefits of Choosing Color Sequential Display Technology
There are three primary benefits to using a color sequential display:
- Power savings. In traditional backlit LCDs, the backlight uses a tremendous amount of energy to illuminate the screen, in part because it has to push the light through the layers of liquid color filters. By eliminating these elements, designers can reclaim the majority of the power budget they’d otherwise be spending on the display.
- Increased display resolution. Traditional LCDs rely on full pixels that contain red, green, and blue subpixels, but this subdivision isn’t necessary in a FSC display. With the same technical performance, a color sequential display can deliver higher image resolution.
- Improved contrast ratio and richer images overall. By using the color wavelengths directly from the LED backlight with no filter, the resulting image has a wide color gamut and high contrast.
At Azumo, we design products that create exceptional images that can be viewed in any lighting conditions without draining the device’s battery. FSC displays aren’t just an option we admire – it’s the type of display we love to deliver.
Design Concerns and Requirements for Color Sequential Displays
As you might have guessed, FSC displays aren’t entirely free of design limitations.
Until recently, refresh speed was a barrier to popularizing the use of color sequential displays. This was primarily because FSC displays rely on three different color LEDs instead of having one white backlight: this means that to achieve the same image quality as a traditional backlit LCD, an FSC display must refresh three times as quickly to switch between all the three colors.
If the display you’re designing is intended for use on the move, and if the refresh speed isn’t sufficient, your user may experience color breakup.
The good news is that LCD displays are getting faster: the standard used to be 60 to 120 Hz (which translates to 60 to 120 refreshes per second), but today there are displays in development with refresh speeds up to 480 Hz, and they may go higher.
The other major concern is the overall color mix. Typically, a large bezel distance or backlight volume is needed to properly mix the RGB LEDs. This makes the system much more bulky. Additionally, each LED ages and operates differently over its lifetime, often due to the temperature range it’s subjected to. So, by relying on a color-based backlight rather than a uniform white panel, color sequential displays risked aging unevenly and deteriorating rapidly in the wrong conditions.
The good news is that today’s color sequential display technology doesn’t require a traditional backlight at all: Azumo’s lightguide film solves both of these pain points and amplifies the power savings of traditional FSC displays.
Why Now Is the Time for Color Sequential
With LCD refresh speeds higher than ever and the Azumo technology commercialized for frontlit LCD displays, now is the time to revisit the opportunities color sequential displays hold.
Azumo’s backlighting products can operate off of a single RGB LED with a sensor that gauges what color is coming out and that provides the light for the entire display, so it’s not like the traditional, repeating RGB array that risks aging and thermal differences. This is all done without adding any additional bezel size and with less volume than even a traditional white backlight. With Azumo’s technology, these potential issues are taken care of before the light reaches the display. It’s a clean solution to ensure light is delivered the same way at the same time.
Additionally, color sequential displays with the Azumo backlight are lighter than traditional backlit LCDs, an issue that can be further resolved by opting for a front light over a backlight panel.
In addition to the energy budget savings you can achieve by eliminating a backlit LED panel, a color sequential display using Azumo’s thin lightguide delivers a lighter, more flexible option for designers who are working to optimize their products for maximum battery life in the field.
To find out if Azumo’s display lighting products might be the right fit for your next product design, contact our team to start the conversation.
