Microscopic Innovation: A conversation with Nikhil Balram, Mojo's SVP of Displays
The Mojo Blog sat down with Dr. Balram to discuss how the world’s smallest and densest dynamic display is created and uses beyond Mojo Lens
Can you share a little about your background in displays and MicroLEDs and how those experiences led you to join Mojo?
I've been involved in the display industry since 1995. I started working on cockpit displays for planes like the F/A-18E/F Super Hornet —a very exciting area. If you saw the latest Top Gun, you saw some of the things I worked on inside the plane. After that, I was at Google for four and a half years. I ran displays for all Google consumer hardware starting with AR, VR, and then ultimately all hardware.
In the display industry, changes are very slow and they come once a generation; you can see them coming for ten years. LCD was like that; it was the last big change in the market, and it replaced the CRT display entirely. Many of us have come to believe that Micro-LED is that next once-in-a-generation transformation. The Micro-LED technology that Mojo has developed is what got me interested and brought me here.
Outside of Mojo, what’s happening right now in the display field?
The market is actually in transition, with OLED (organic light-emitting diode) entering certain segments of the market. The phone market is about 50% OLED, and OLEDs make up a small portion of the TV market, the premium section. But organic LEDs have some fundamental limitations that don’t allow them to be that market-transformation agent. Organic LEDs cannot be driven very hard, so they’re fundamentally limited in brightness.
By comparison, inorganic LEDs, which we are shrinking to make Micro-LEDs, can be driven with a hundred times higher current so that you can create very bright displays. If you can make very bright displays, you can use the displays across any application. But MicroLED does not really exist in the market yet because it's a new technology.
It takes a relatively long time for a new display technology to enter the market because displays have such complicated manufacturing processes. You might see an amazing prototype at a show, and then it may take ten years for that to be producible at a scale and cost for most consumers. So that's where MicroLED displays are right now: the promise has been proved, but the manufacturing infrastructure is not in place. That's what people like us are working on.
As well as earning several US patents, the Mojo display has also set some world records. What are the ways in which the Mojo display is unlike any display in history?
Let me give you a very precisely worded answer: Mojo Lens has the world's smallest and densest dynamic display. And by dynamic display we mean a display that can change images and reproduce video. There may be smaller Micro-LEDs and smaller displays, but as far as we know they’re not dynamic, so they can’t turn on and off quickly or show shades of grey.
If you laid the Mojo Micro-LEDs side by side, how many would there be in one inch? And how many Micro-LEDs are currently in the mojo lens?
The pixel pitch of the Mojo display is 1.8 microns. When you lay them side by side, you get a little over 14,000 pixels—and 14,000 Micro-LEDs—per inch.
In what color do texts and images display on Mojo lens? Why is this color ideal from a user perspective?
Short answer: we use green because it appears brightest to the eye. The Mojo Lens display could have been in any color that we chose. And green was specifically chosen because it had the best performance.
Our visual system is peaked at translating what we think of as green into a sensation of brightness. (Green here refers to a wavelength that peaks around 550 nanometers.) That exactly matches the peak of the spectral response, the photopic response of our eye.
What that means in English is that response curve of our visual system is how we perceive brightness, and that's the reason why if I show you a blue image that’s the same brightness, you will not find it as bright. With blue, there's a very inefficient conversion of blue wavelengths to a sensation of brightness. That’s why green has a long history of being used in monochromatic displays, and why we’re using it for ours.
Are there plans to move beyond green and into full-color displays?
Color is coming. It's not that the green display is the end of our roadmap; with the next product we'll be able to do RGB. Achieving full color at such high pixel densities with Micro-LED has been a very big, unsolved problem that a lot of our people have been working on. It’s very important for us to let people know that we have an approach for achieving RGB.
Now that Mojo's perfected this super-dense MicroLED display, what are some other uses for it outside of Mojo Lens?
For us, there's a benefit in our display technology finding other use cases, because ultimately the cost of a display is tied to the volume. To that end, we have been promoting the tech display technology as something that people could use for other applications outside of Mojo Lens.
We think Mojo Lens is probably the tiniest use case possible for a display. So other companies would probably want a larger display. But if you can make something very tiny, you can make it bigger. So far, we've gone to one end of the scale. If we make it slightly bigger, you can use it in AR glasses. If you make it even bigger, you can put it in VR. If you make it even bigger, it can be in a watch, a phone, a laptop, a TV, and so on. We think our display technology is suitable for any of those use cases. It won't be the same design, it won't be 14,000 PPI in those applications because that resolution isn’t necessary. Pixel density will be appropriate for those applications, but the fundamental technology is applicable to the entire range of the market.
If you could send other companies a personal message about using Mojo technology, what would you say to them?
I would say that we have the world's best Micro-LED technology. We developed it in service of our use case—the smart contact lens—but we realize that it has much broader applicability. We encourage other people to reach out to us about using our technology in their applications.