• 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 ≤445nm 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:

QINCIDENT = 12.1W (measured)

AARRAY = ((8.7072mm × 4.9184mm) ÷ 100mm2/cm2) = 0.4283cm2 (data sheet)

OVILL = 16.3% (optical model)

OPUV-RATIO = 0.00021 (spectral measurement)

OPVIS-RATIO = 0.99977 (spectral measurement)

OPIR-RATIO = 0.00002 (spectral measurement)

OPBLU-RATIO = 0.28100 (spectral measurement)

OPBLU1-RATIO = 0.03200 (spectral measurement)

AILL = 0.4283cm2 ÷ (1 - 0.163) = 0.5117cm2

ILLUV = [0.00021 × 12.1W] × 1000 ÷ 0.5117cm2 = 4.966mW/cm2

DLP391TP

DLPS289A – JUNE 2025 – REVISED SEPTEMBER 2025

www.ti.com

26

Submit Document Feedback

Copyright © 2025 Texas Instruments Incorporated

Product Folder Links: DLP391TP