25 Sep 2018
Can the Success of OLED Displays be Transferred to Lighting?
Despite great success in the market for high-end cell phone displays, OLED technology has yet to achieve significant entry into the general lighting market. This is mainly due to the relatively high cost, but also by manufacturing problems in achieving the innovative form factors promised in concept papers and prototypes. Although steady progress is being made in device performance and fabrication techniques, the production of exciting new products at affordable prices remains challenging. This talk will assess the progress in commercialization and discuss the obstacles that remain to achieve high-volume sales.
The challenges can be gathered into three categories.
• Organic molecules offer a very efficient way of converting electricity into light without the formation of a strong blue peak in the spectrum. However, most of the light is trapped inside the device. Substantial progress has been made in enhancing light extraction, but solutions that are compatible with flexible substrate are still needed.
• Lifetime concerns have been ameliorated by the development of multi-stack structures. However, these solutions increase the complexity and thus the cost of the device. Further development of stable blue emitters will be necessary to keep up with future efficacy increases in LEDs.
• The angular distribution of the emitted light is close to Lambertian. This is appropriate for some cases, but the ability to tailor the beam shape is needed for many applications.
• The OLED spectrum is advantageous for production of warm white lighting. Tunable color can be enabled in principle, but commercialization will be difficult.
• Substantial reductions in equipment depreciation charges are essential to enable high volume sales. Although roll-to-roll fabrication has been suggested as the key to higher throughput, shortening the time taken for each process step may be more effective.
• The cost of organic materials will be driven down by the increased demand for display applications. However, the materials must be tuned to each manufacturer’s approach to OLED lighting and small companies may not have as much bargaining power as the major OLED display manufacturers in negotiations with suppliers.
• Most of the bill for materials is associated with inorganic materials outside the organic stack. Achieving the desired cost reductions may be more difficult.
• Although printing techniques could lead to major cost savings, adoption has been very slow and concern remains about the impact on performance. Synergy with display applications should be helpful, although not all components are common to both applications.
• The reputation of some manufacturers of OLED lighting has been damaged by the premature demonstration of devices that have not been brought in high-volume production and for poor performance of innovative products.
• Most manufacturers have not been able to maintain strong business partnerships with the major lighting companies and have opted instead to develop their own routes to market. Some small luminaire manufacturers have bravely experimented with OLED panels, but the development of profitable products requires resources that are not available to many small companies.
• Although the progress in using OLEDs for automotive rear lights is very promising, there has been little success elsewhere in the development of products that clearly benefit from the advantages of OLED sources and are included in the portfolio of luminaire manufacturers, distributors and lighting specifiers.