The Opportunities and Challenges Facing the Display Industry
June 2, 2015, Society for Information Display Symposium, San Jose, CA—In-Byeong Kang from LG Display presented a forward and backward looking view of the display industry in the symposium’s third keynote. The trends and drivers for change are more easily viewed from a historical perspective.
Over the past 20 years, displays have changed many parameters, including size and resolution. As displays reduced total volume from CRTs to plat panels, the volume of displays also changed. In 2000, CRTs accounted for 200 M units, and by this year the LCD displays will sell over 3B units.
The evolution of the flat panel required a lot of technology changes and the evaluation of lots of concepts for the displays—emissive, reflective, transmissive, active, passive, etc.—but eventually the industry settled on LCD. The first LCD screens were on laptops and supported a 10-inch VGA resolution display that provided 100 nits at 80 pixels per inch. In comparison, the latest TV sets have a viewing angle of over 45 degrees and are over 110 inches and over 500 ppi.
The technological efforts to effect these types of changes are huge. For example, increasing the viewing angle of a display included work on chemistries and in manufacturing flows. The first TV panel was to be 18.1 inches and emit 200 nits all for about $3,000. One problem was the liquid crystal injection took 23 hours on fairly small gen 2 panels. The chemistry was changed to IPS and a 1-drop fill process. The next version was a 21.9 inch set that cost about $1,000.
As panel sizes increased, there was another set of decisions on LCD versus plasma for a 42 inch, 500 nit display. This TV set was manufactured on gen 4 glass and used copper metallization to provide better RC characteristics for the much longer lines. The latest unit is 105 inches and 500 nits with a 5120 x 2160 resolution. Unfortunately, this TV will cost a lot of money.
Even in the small screens there are still lots of issues. The latest screens need very high resolution going from 150 to over 500 ppi. The mobility of the small screen users requires that the displays be sunlight visible, leading to power issues and problems with haze and glare that are exacerbated by the touch functions. The current solution is OLED for the high emission, with UV alignment, and in-cell touch sensors.
The markets have grown with each generation of new application from laptop, to TV, to phones, and tablets. Now, the markets seem to be close to saturation and annual growth is likely to be fairly flat through ’22. the challenge for the manufacturers is to balance capacity and investment against the likely market size and growth. Overinvestment leads to over supply and a drop in price. Underinvestment leads to shortages.
Their view for future displays include displays everywhere, on any surface. The windows for a bedroom could have light shutters to allow for sunlight and outdoor views, or opaque. The autonomous cars would have multiple displays and connectivity options. Some displays will be rollable or foldable and content will be easily moved from a phone to a larger display with a swipe. The displays will range from window-size or building size to the IoT and wearable devices. There will be more display spaces and modes in every size from room, to home, to office, to city.
Some of these displays will be transparent and some will be flexible, making OLED the most likely choice for the technology. The challenges will include the flex and its accompanying issues like bend radius and thickness. Reliability will be addressed through materials that can handle the bending and methods to reduce the stresses associated with bending. One possibility is to use laminated assemblies and flexible glass may be displaced with plastic.
Transparent displays need to have glass-like characteristics like clarity and smoothness. High image quality is paramount in a transparent or reflective display, so these displays will probably need some type of optical shutter that will be made of some currently unknown technology and material.
The move to commercialize such devices requires robust design of all elements; electrical, mechanical, and chemical. The user experience will require a different set of interfaces and apps will have to become invisible. The ecosystem for this new environment will need a full ecosystem of materials, components, equipment, and panels, and each needs to add to the end product design.
