T8 Tube
09/10/2013 08:57
Instrumentation used SUV3000 UV-Vis radiation analyzers, the measurement process in a standard darkroom . Figure 3 shows the measurement results .
Illuminance values measured illuminance values and expectations of the average error of 15 lx, measured value and the desired color temperature color temperature average error of 23 K.
Table 1 Experiment with the basic parameters of the LED
During the experiment , the measured and theoretical values there are some errors , but overall still got a good match. Errors are mainly from the following aspects: 1 ) the process as the experiment progresses , LED chip junction temperature rising . Junction temperature change would cause the light measurement and color measurement changes. 2 ) drive the LED chip PWM waveform is not the ideal square wave. Even in the same switching state , the current is not constant.
The change in drive current will cause the LED light and color measurement metrics changes. The smaller the duty cycle , this error is caused by the greater .
3) LED individual difference. Even in the same model, the same batch of the LED, the light will be different metrics, and color measurement , particularly the dynamic characteristics of both . In the experiment, the same kind that has the same light color LED electrical parameters and dynamic characteristics . 4 ) instrumentation systematic errors and random errors during operation .
