The calculation of the optical power density of the illumination on the DMD in the different wavelength bands uses the total measured optical power on the DMD, percent illumination overfill, area of the active array, and ratio of the spectrum in the wavelength band of interest to the total spectral optical power.
- ILLUV = [OPUV-RATIO ×
QINCIDENT] × 1000 (mW/W) ÷ AILL (mW/cm2)
- ILLVIS = [OPVIS-RATIO × QINCIDENT] ÷ AILL (W/cm2)
- ILLIR = [OPIR-RATIO ×
QINCIDENT] × 1000 (mW/W) ÷ AILL (mW/cm2)
- ILLBLU = [OPBLU-RATIO × QINCIDENT] ÷ AILL (W/cm2)
- ILLBLU1 = [OPBLU1-RATIO × QINCIDENT] ÷ AILL (W/cm2)
- AILL = AARRAY ÷ (1 –
OVILL) (cm2)
where:
- ILLUV = UV illumination power density on the DMD (mW/cm2)
- ILLVIS = VIS illumination power density on the DMD (W/cm2)
- ILLIR = IR illumination power density on the DMD (mW/cm2)
- ILLBLU = BLU illumination power density on the DMD (W/cm2)
- ILLBLU1 = BLU1 illumination power density on the DMD (W/cm2)
- AILL = illumination area on the DMD (cm2)
- QINCIDENT = total incident optical power on DMD (W) (measured)
- AARRAY = area of the array (cm 2) (data sheet)
- OVILL = percent of total illumination on the DMD outside the array (%) (optical model)
- OPUV-RATIO = ratio of the optical power for wavelengths <410nm to the total optical power in the illumination spectrum (spectral measurement)
- OPVIS-RATIO = ratio of the optical power for wavelengths ≥410nm and ≤800nm to the total optical power in the illumination spectrum (spectral measurement)
- OPIR-RATIO = ratio of the optical power for wavelengths >800nm to the total optical power in the illumination spectrum (spectral measurement)
- OPBLU-RATIO = ratio of the optical power for wavelengths ≥410nm and ≤475nm to the total optical power in the illumination spectrum (spectral measurement)
- OPBLU1-RATIO = ratio of the optical power for wavelengths ≥410nm and ≤440nm to the total optical power in the illumination spectrum (spectral measurement)
The illumination area varies and depends on the illumination overfill. The total illumination area on the DMD is the array area and the overfill area around the array. The optical model is used to determine the percent of the total illumination on the DMD that is outside the array (OVILL) and the percent of the total illumination that is on the active array. From these values, the illumination area (AILL) is calculated. The illumination is assumed to be uniform across the entire array.
From the measured illumination spectrum, the ratio of the optical power in the wavelength bands of interest to the total optical power is calculated.
Sample calculation:
Equation 12. QINCIDENT = 25W (measured)
Equation 13. AARRAY = (10.368mm ×
5.832mm) ÷ 100cm2/mm2 = 0.6047cm2 (data
sheet)
Equation 14. OVILL = 16.3% (optical model)
Equation 15. OPUV-RATIO = 0.00017 (spectral measurement)
Equation 16. OPVIS-RATIO = 0.99977 (spectral measurement)
Equation 17. OPIR-RATIO = 0.00006 (spectral measurement)
Equation 18. OPBLU-RATIO = 0.28100 (spectral measurement)
Equation 19. OPBLU1-RATIO = 0.03200 (spectral measurement)
Equation 20. AILL =
0.6047cm2 ÷ (1 – 0.163) = 0.7224cm2
Equation 21. ILLUV = [0.00017 × 25W] ×
1000mW/W ÷ 0.7224cm2 = 5.883mW/cm2
Equation 22. ILLVIS = [0.99977 × 25W] ÷ 0.7224cm2 = 34.60W/cm2
Equation 23. ILLIR = [0.00006 × 25W] × 1000mW/W ÷ 0.7224cm2 = 2.076mW/cm2
Equation 24. ILLBLU = [0.28100 × 25W] ÷ 0.7224cm2 = 9.72W/cm2
Equation 25. ILLBLU1 = [0.03200 × 25W] ÷ 0.7224cm2 = 1.11W/cm2