ILLVIS = [0.99977 × 12.1W] ÷ 0.5117cm2 = 23.64W/cm2

ILLIR = [0.00002 × 12.1W] × 1000 ÷ 0.5117cm2 = 0.473mW/cm2

ILLBLU = [0.28100 × 12.1W] ÷ 0.5117cm2 = 6.64W/cm2

ILLBLU1 = [0.03200 × 12.1W] ÷ 0.5117cm2 = 0.757W/cm2

6.8 Window Aperture Illumination Overfill Calculation

The amount of optical overfill on the critical area of the window aperture cannot be measured directly. For

systems with uniform illumination on the array, the amount is determined using the total measured incident

optical power on the DMD, and the ratio of the total optical power on the DMD that is on the defined critical area.

The optical model is used to determine the percentage of optical power on the window aperture critical area and

estimate the size of the area.

• QAP-ILL = [QINCIDENT × OPAP_ILL_RATIO] ÷ AAP_ILL (W/cm2)

where:

• QAP-ILL = window aperture illumination overfill (W/cm2)

• QINCIDENT = total incident optical power on the DMD (Watts) (measured)

• OPAP_ILL_RATIO = ratio of the optical power on the critical area of the window aperture to the total optical

power on the DMD (optical model)

• AAP-ILL = size of the window aperture critical area (cm2) (data sheet)

• OPCA_RATIO = percent of the window aperture critical area with incident optical power (%) (optical model)

Sample calculation:

Array

0.5 mm

Window

Aperture

Window Aperture

Window

Window

Window Aperture

Critical Area

Illumination on Aperture Critical Area

(estimated to cover 25% of critical area)

Illumination Profile

Figure 6-3. Window Aperture Overfill Example

See the above figure for the length of the critical aperture.

QINCIDENT = 12.1W (measured)

(6)

OPAP_ILL_RATIO = 0.312% (optical model)

(7)

OVCA_RATIO = 25% (optical model)

(8)

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DLP391TP

DLPS289A – JUNE 2025 – REVISED SEPTEMBER 2025

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