Plaque tester

Let us suppose that we have prepared a series of phosphor compositions wherein the activator concentration was the variable. We would need to measure these samples to determine which concentration was near to the optimum. Let us further suppose that we wish to use our phosphor in a LPMV lamp application. Although we could manufacture a test-lamp, usually this is not very feasible. What we do is to prepare a thick layer on a holder and compare it to a "standard" phosphor having similar emission characteristics. The layer is called a "plaque" and the apparatus is called a "plaque-tester", as shown in the following ... 

Figure 8.16 shows the principal components of a coefficient of friction tester. Polymer samples in the form of thick sheets or molded plaques are attached to the base and a sled with standard dimensions, weight, and surface properties is drawn over the surface. The load beam measures the force required to initiate movement and sustain motion at a given rate of crosshead travel. Thin films can be taped to the sled and drawn across a contact surface that has known properties. 

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