Qualcomm is one of the biggest companies involved in the development of MEMS technologies and has been working on its own Mirasol display for a little while. In the pursuit of developing an MEMS based display the company has also lent some serious financial support to display manufacturer Sharp. The two have been working on MEMS together for the past year and have recently been showing off what they’ve been working on.
This display technology could be a game changer, but first let’s take a look at how it works.
MEMS has a lot in common with popular LCD displays. They share a similar backlighting structure, but rather than a white backlight filtered into individual pixels by red, green, and blue color filters, MEMS systems use a set of mechanical shutters that open and close at very high speeds.
Above is a comparison between LCD liquid crystal filtering and a MEMS shutter. Source: Japan Tech
Rather than leaving the backlight to produce a full color spectrum (white light), MEMS displays make use of a RBG LED backlight, which flashes between red, green, and blue in quick succession. By adjusting the open and close speed of the shutters, thereby blocking and unblocking the backlight multiple times a second, individual colors can be filtered through, producing a similar result to LCD’s polarized filters.
The movement speed of the shutters and their position controls the amount of light let through from the backlight, determining the color displayed and its intensity. Clearly then, when the shutters are closed no light passes, creating a black pixel. When left completely open the eye should see a white pixel. MEMS displays can create various hues and color intensities by balancing the speed and open/close conditions of multiple shutters in time with the various backlight colors.
A close-up of an MEMS display courtesy of DigitalVersus. Note that the small shutters can create a variety of shades and how the closed shutters produce dark pixels.
As you can probably tell it’s a pretty tricky piece of technology to pull off, but it does have a few advantages over existing display types.
Is MEMS better than LCD or OLED?
It’s tough to say without comparing the displays in the flesh, but MEMS has some significant benefits on paper that make it a very interesting piece of tech.
The biggest benefit to MEMS technology is that it can allow all of the light through its filters, compared with LCD displays which can waste up to two thirds of the backlights brightness before it even leaves the display. Obviously displays don’t need to be any brighter, so this means that developers can reduce the intensity of an MEMS backlight without losing brightness, which could lead to a significant saving of battery life. Since displays are the biggest battery draining components, especially in larger tablets, MEMS is a great solution for mobile devices.
MEMS displays also require fewer individual LEDs than OLED. This makes the technology more cost and energy efficient in certain scenarios. However the use of a backlight system could mean that MEMS will use more power on darker images, compared with OLED which can simply switch of individual LEDs.
Over the long term, image quality may also turn out to be superior to OLED as well, as there is a lower risk of the dreaded selective pixel degradation that can lead to distorted colors.
This technology is also much closer to release than you might think. Qualcomm has already released its own Toq smartwatch which has a Mirasol display (based on MEMS). The first wave of tablets loaded with MEMS displays are due to land within the next six months, according to Sharp’s engineers. There was also a demonstration 7” tablet hidden away in a corner of this year’s CES, featuring a 1280×768 pixel MEMS display. The technology is clearly on its way.
A 1.55″ smartwatch and 7″ tablet demonstrates that the technology is viable in a range of devices, but we’ll have to see if MEMS displays can be produced cheaply at higher resolutions.
Due to the technology’s infancy and complexity, it will initially hit the market at a higher price than current LCD displays, but could offer manufactures a cheaper alternative to expensive OLED technology. I wouldn’t be surprised if MEMS becomes a serious contender to both LCD and OLED, but we’ll have to wait and see how good the technology is in the flesh.