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 ÷ AILL (mW/cm2)
- ILLVIS =
[OPVIS-RATIO × QINCIDENT] ÷ AILL (W/cm2)
- ILLIR = [OPIR-RATIO
× QINCIDENT] × 1000 ÷ 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 ≥410 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 ≥410 and ≤475nm to the total optical power in the
illumination spectrum (spectral measurement)
- OPBLU1-RATIO = ratio of the
optical power for wavelengths ≥410 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
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 8. QINCIDENT = 80W
(measured)
Equation 9. AARRAY = (17.280mm × 9.720mm) ÷ 100 = 1.6796cm2 (data sheet)
Equation 10. OVILL = 16.3% (optical model)
Equation 11. OPUV-RATIO = 0.00017
(spectral measurement)
Equation 12. OPVIS-RATIO =
0.99977 (spectral measurement)
Equation 13. OPIR-RATIO = 0.00006
(spectral measurement)
Equation 14. OPBLU-RATIO =
0.28100 (spectral measurement)
Equation 15. OPBLU1-RATIO =
0.03200 (spectral measurement)
Equation 16. AILL = 1.6796cm2 ÷ (1 - 0.163) = 2.0067cm2
Equation 17. ILLUV = [0.00017 ×
80W] × 1000 ÷ 2.0067cm2 =
6.78mW/cm2
Equation 18. ILLVIS = [0.99977 ×
80W] ÷ 2.0067cm2 = 39.86W/cm2
Equation 19. ILLIR = [0.00006 ×
80W] × 1000 ÷ 2.0067cm2 =
2.39mW/cm2
Equation 20. ILLBLU = [0.28100 ×
80W] ÷ 2.0067cm2 = 11.20W/cm2
Equation 21. ILLBLU1 = [0.03200 ×
80W] ÷ 2.0067cm2 = 1.28W/cm2