Devices light-reflecting

FIGURE 6.28 The ambient light reflection as a function of the wavelength measured for a control device and structurally identical OLEDs made with two different bilayer ITO anodes. 

L.S. Hung and J.K. Madathil, Reduction of Ambient-Light-Reflection in Organic Light-Emitting Devices, U.S. Patent 6,429,451 Bl, 2002. 

It was shown earlier that the efficiency of the diode depends significantly on the thicknesses of the layers due to the optical field distribution inside the device, caused by the interference of the incoming light with light reflected from the mirror cathode. The blend diode is always more efficient than the neat diode. The excitation created by absorption in the PPV phase is transferred to the polythiophene, where a more efficient charge separation process is possible, as is clear from Figs. 6.10 and 6.11. 

A wide range of devices fall into this category, including single-pad urine tests (dipsticks) that are read visually more complex strips that use light reflectance for measurement and fabricated cassettes or cartridges that incorporate tech-... 

It is conceivable that future outdoor displays will combine different approaches intensity control, microstructure for light extraction, or displays based on reflection might be used, but they will certainly include reflection-suppressing designs. As we saw earlier, efficiently suppressing the light reflection from the device requires an integration of the antireflection... 

In another detection method, an oil sorbent is used that changes in physical properties when it absorbs oil and thus triggers a device. An example of this would be a sorbent that loses it strength when oil is absorbed. The sorbent is placed in contact with a spring and a switch, which is activated when oil enters the sorbent. This type of device is not effective for fast response. Other detection units are triggered by the differential light reflection or absorption properties of oil. 

As you can see, the fabrication is rather simple. Yet, the light output rivals many of the LED s and is certainly more than the output of phosphor screens in certain devices. A conductive layer is required for electron injection into the electron transport layer (ETL). The metal electrode (ME) is composed of Al, Ag or Ag-Mg, and is usualfy light reflective. The hole transport layer (HTL) Injects holes from the transparent electrode (TE) into the HIL. The point where the excitons, i.e.- pairs of holes electrons, recombine is the b ht emitting (LE) region. This can vary according to the type of compounds used to form the two organic layers. These devices can be classified as ... 

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