DLPA078B February   2017  – September 2021 DLP160AP , DLP160CP , DLP2000 , DLP2010 , DLP230GP , DLP230KP , DLP230NP , DLP3010 , DLP3310 , DLP4710 , DLP471TP , DLPC3420 , DLPC3421

 

  1.   Trademarks
  2. 1 Introduction to Optical Modules
    1. 1.1 DLP Pico Chip or Digital Micromirror Device (DMD)
    2. 1.2 Illumination
    3. 1.3 llumination Optics
    4. 1.4 Projection Optics
    5. 1.5 Flash Memory Board
  3. 2 Use Case Considerations
    1. 2.1 Optical Module Specifications
  4. 3 Core Optical Module Specifications
    1. 3.1 Brightness
    2. 3.2 Size
    3. 3.3 Resolution
    4. 3.4 Illumination Power Consumption
    5. 3.5 Throw Ratio
    6. 3.6 Offset
    7. 3.7 Contrast Ratio
  5. 4 Additional Optical Module Specifications
    1. 4.1 Brightness Uniformity
    2. 4.2 Focus Uniformity
    3. 4.3 Color Management
    4. 4.4 Illumination Type
    5. 4.5 Thermal Management
    6. 4.6 Optical Zoom
    7. 4.7 Depth of Focus
    8. 4.8 Focus Method
    9. 4.9 Automatic White Point Correction
  6. 5 Features Implemented in Software
    1. 5.1 Keystone Correction
    2. 5.2 DLP Image Processing Settings
    3. 5.3 DLP IntelliBright Algorithms
  7. 6 Hardware Integration Considerations
    1. 6.1 Flash Memory
    2. 6.2 DLP Controller to DMD Interface
    3. 6.3 Flash Memory to DLP Controller Interface
  8. 7 Business Considerations
    1. 7.1 Cost
    2. 7.2 Custom Optical Modules
    3. 7.3 Minimum Order Quantity (MOQ)
    4. 7.4 Lead Times
  9. 8 Example Optical Module Specification Table
  10. 9 Get Started with Development
  11. 10Revision History

3.7 Contrast Ratio

There are two general methods of measuring the contrast ratio of a projection system: Full On / Full Off (FOFO) and methods using a checkerboard pattern, such as the IEC 61947 contrast standard, also known as ANSI contrast. FOFO contrast is more commonly used by optical module manufacturers.

FOFO contrast measures the ratio of the brightness of an entirely white projected image versus an entirely black projected image. The checkerboard pattern methods measure contrast using a 4 × 4 array of black and white rectangles. In both cases, the measurement is normalized as “x to 1.”

The FOFO contrast measurement is primarily impacted by the inherent contrast ratio of the DMD, whereas the checkerboard measurement is influenced by both the inherent contrast of the DMD and the contrast performance of the projection optics. As such, FOFO contrast is higher than checkerboard contrast. Checkerboard contrast is more indicative of the true contrast performance of an optical module when displaying actual video content.

Higher contrast optical modules can create more vibrant, colorful projected images while projected images from lower contrast optical modules can look washed out (see Figure 3-5).

GUID-1EF7628C-4643-4C45-AF8F-52206D2BD5D3-low.gifFigure 3-5 A Simulation of a High Contrast Projected Image (Above) and a Low Contrast Projected Image (Below)