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100 DESIGN007 MAGAZINE I NOVEMBER 2019 ure 7 shows a summary of the tests and sam- ple sizes. At the end of the reliability tests, we checked the functionality of the Type1-LEDs. The rapid change of temperature test did not cause any Type1-LED failures; all of the 480 Type1-LEDs were functional after 1,000 cycles between -40°C and +85°C. Steady-state temperature/ humidity (85°C/85% RH) caused one Type1- LED to fail. The failed LED was in a certifica- tion platform that had been powered on dur- ing testing. The other 479 Type1-LEDs were functional after 1,000 hours of elevated tem- perature and humidity. We also measured light luminance and color coor- dinates from some of the tested Type1-LEDs. Reli- ability testing did not cause any adverse effects. Physical Failure Analysis Results from Type1-LED Electrical measurements indicated that the failed Type1-LED had an internal component short-circuit. Nevertheless, we made a cross-section of the failed component because it had been mounted on top of the thermoformed 3D- curve. The cross-section showed that the compo- nent base had bent slight- for certification layout and ma- terial stack. Components un- dergo surface mounting, form- ing, and injection molding, and they are tested after each pro- cess step. The testing system is also standardized. If the manu- facturing yield is sufficient, the test platforms are subjected to reliability testing. Typical envi- ronmental loads include change of temperature as well as elevat- ed temperature humidity. Based on test results and physical fail- ure analysis, components can receive certifica- tion for use in commercial projects. Reliability Testing Results The results presented here are part of the cer- tification process for Type1-LED that was test- ed using an internal certification platform (Fig- ure 6). Each certification platform contains 48 Type1-LEDs. We have surface-mounted some of the Type1-LEDs on top of small radius 3D curves. This is against our design guidelines, but we wanted to push the limits of the tech- nology and gain an understanding of potential failure modes under adverse conditions. Fig- Figure 6: Photo of two certification platforms that were subjected to extended reliability testing. Figure 7: Summary of tests and sample sizes in Type1-LED reliability testing.