Transparent displays have been around for many years, but have enjoyed only partial success. In the military and the automotive industry, heads-up displays (HUDs) have been available for decades. On the retail side, a number of niche suppliers have been providing transparent displays with limited capabilities for almost as long.
One reason why transparent displays have not been a big revenue generator so far is that actual demand for transparent displays is limited. Who in the world really needs a display that one can see through? In addition, for various technical reasons, transparent displays offer limited image capabilities. However, NanoMarkets believes this situation is all about to change:
On the supply side, the display industry is gradually making a shift to organic light emitting diode (OLED) technology, which is easier to turn into transparent displays than the dominant liquid crystal display (LCD) technology.
On the demand side, new augmented reality (AR) applications seem to call for new types of hardware platforms with transparent displays. The most obvious example of this kind of platform is Google Glass, but we note that another dozen or so firms are offering products of the Google Glass kind, and both Apple and Microsoft have shown interest in devices with transparent displays.
Most of this technology is only barely on the market. NanoMarkets believes, however, that the growing attention that these futuristic applications and associated transparent displays are getting has proved a call to action for the more conventional sectors of the display industry.
As a result, we are seeing LCD firms coming up with clever ways around the technical problems that have hampered the rise of transparent displays. In a highly competitive economic environment, the retail and advertising sectors are finding these precursor transparent displays useful, and the revenue from transparent displays is already beginning to grow.
NanoMarkets believes that transparent displays represent a substantial opportunity over the next decade. However, we do caution that both the market and technical risks are quite daunting in our opinion.
The market risks are high because there is not a full understanding of how transparent displays fit into the retail and advertising market going forward. Even more uncertain are the prospects for AR, a primarily software-based technology that is fueling much of the current attention in transparent displays.
The Problem of Invisible Components in LCD Displays
The technical problems of creating transparent displays are equally worrying for display makers, especially for LCD firms. In particular, the need for a transparent display immediately raises the problem of how to create “invisible” backlighting and color filters.
Backlighting: Since most of the transparent displays that will hit the market in the next few years are going to be LCDs, backlighting is an obvious challenge. NanoMarkets sees several theoretical solutions to this issue, but really only one that has much commercial potential.
Backlighting itself could be made transparent using zinc oxide (ZnO) LEDs, but such devices are more an interesting R&D topic than anything else. Another possibility – but an expensive one – is the use of additional optics so that the LEDs are not positioned directly behind the display.
The solution that most transparent LCDs are using – and, we believe will continue to use – is simply to make use of ambient light. Samsung and JNM Display Company – both Korean companies – are already supplying transparent displays using ambient light. The problem, of course, is that when there is no light, the display doesn’t work.
As we see it, this limitation is a serious negative for this type of display, and one that is not easily overcome. However, there is still some room for innovation here. For instance, Eyevis’ (Germany) transparent LCD technology uses ambient light during the day while it is transparent and changes to a more conventional dark background during the night. However, this type of approach isn’t going to save the fortunes of the transparent LCD!
Color filters: A similar set of issues can be found with color filters, which are also not transparent. Again, the typical solution with transparent displays is to remove the color filter. While doing so makes it easier to make the LCD transparent, sacrificing color is a huge backward step for transparent displays.
We think that any transparent display company that sacrifices color thinking that it will not be hurt in the marketplace should take a look at the electrochromic display business, which has been devastated by “retina displays” and the like - in part because it has proved completely unable to provide attractive color.