A new supply chain report this morning claims that both Samsung and LG Display are reviewing ways to apply low refractive index CPL to displays for smartwatches and smartphones. Adding low refractive index CPL to high refractive index CPL that is already being applied can increase light efficiency and have a positive effect on product life. The two panel makers are conducting low refractive index CPL tests with several OLED material makers.

Technically speaking, CPL is an auxiliary layer formed on the cathode of the functional layer that emits light in OLED. CPL reduces light loss that occurs when light from the OLED light emitting layer is repeatedly reflected by electrodes (cathode/anode) and helps direct the light toward the display. CPL, which is currently being mass-produced for small and medium-sized OLEDs, is a high-refractive CPL, which reduces power consumption by using materials with a higher refractive index than conventional CPLs in the past.

The low refractive index CPL, which Samsung Display and LG Display are planning to apply additionally to small and medium-sized OLEDs, serves to gather light together with the existing high refractive index CPL. Since light is scattered in all directions, light loss can be further reduced by applying both high-refraction and low-refraction CPLs. Other functional layers also have a refractive effect.

However, since adding a low refractive index CPL adds one auxiliary layer, process and price may become obstacles. In order for the two panel makers to apply low refractive index CPL to small and medium-sized OLEDs, they need to persuade Apple and other potential customers of its benefits. For more on this, review the full report from The Elec.