Creating a Display Source

The Display Source allows you to model the light emission of a display (LCD, control panel etc.) taking into account its physical properties such as the flux, the spectrum, the emittance and the intensity.

Important: This feature is only available under Speos Premium or Enterprise license.

To create a Display Source:

Important: In case you want to add the source in a Direct simulation, make sure that all parts of the source are enclosed in one single body, or in one ambient material, and therefore are not located in two (or more) bodies or ambient materials. Otherwise you may generate propagation errors.
  1. From the Light Simulation tab, click Display .
  2. In Image, from the File drop-down list, click Browse to load a *.jpeg., *.png, *.bmp, *.tiff, or *.rgb file.

    A preview of the image and the rays appears in the 3D view.

    Note: If you do not see the image correctly, adjust the axis system. The image must be projected on Z (normal to the display). This ensures that what you see in the 3D view corresponds to the XMP result.
  3. Define the dimensions of the display:
    1. If you want light from all space, set Mirror extent to True to link the start and end values.
    2. Edit the X and Y coordinates of the start and end points of the display either by entering the values or by using the manipulators in the 3D view.
  4. In Flux, specify the luminance of the brightest pixel (white pixel). The luminance is calculated according to this reference pixel.
  5. If you want to edit the Contrast Ratio of the display, set Infinite contrast ratio to False.
    Tip: The contrast ratio is a property of display systems. It is the measurement of the ratio between the darkest blacks and the brightest whites.

    Standard values range from 500:1 to 1000:1 for a LCD.

  6. In Intensity, set the intensity distribution of the display source. From the Type drop-down list:

    • Select Lambertian for a uniform distribution and in Total angle set the angle of emission of the display source.

      Note: By default Total angle is set to 180° so that the source emits on a hemisphere.

    • Select Cos for a distribution that follows a cosine law at nth order and set the total angle of the surface source's emission.

      In N, set the order of the cosine law.

    • Select Symmetric Gaussian and set the FWHM Angle.

      FWHM Angle has the same value for x and y and is computed on both axes.

    • If you want to define different FWHM values on X and Y, select Asymmetric Gaussian:
      • Set the FWHM angle for X and Y.

      • In the 3D view, click two lines to define X direction and Y direction.

        Note: If you define manually one axis only, the other axis is automatically (and randomly) calculated by Speos in the 3D view. However, the other axis in the Definition panel may not correspond to the axis in the 3D view. Please refer to the axis in the 3D view.
    • Select Library and click Browse to load an *.ies or *.ldt file.
      • If you want to see the file's properties or edit the file, click Open file to open the IESNA Viewer.
      • To set the orientation of the source intensity distribution, click two lines to define X and Y direction.
      Note: When using an intensity file, the maximum value of the intensity diagram is always considered at the normal incidence. However if the real maximum value of the intensity diagram is not located at the normal incidence, you may face with unexpected measured values.
  7. In Color Space, from the Type drop-down list, select which color space based model to use according to your needs and screen's capacities.
    • Select sRGB to use the standard and most commonly used RGB based model.
    • Select Adobe RGB to use a larger gamut.
    • Select User Defined RGB to manually define the white point of the standard illuminant. From the White Point Type drop-down list:

      • Select D65 to use a standard daylight illuminant that provides accurate color perception and evaluation.
      • Select D50 to use a natural, horizon light.
      • Select C to use an average daylight illuminant.
      • Select E to use an illuminant that gives equal weight to all wavelengths.
      • Select User defined if you want to edit the x and y coordinates of the white point (the reference point of the model).

        Note: For more information about color models or white points of standard illuminants, see Colorimetric illuminants.
  8. If you selected User Defined RGB from the Color Space drop-down list, load a spectrum file for each primary color.
    If you want to modify or create a *.spectrum file, click Open file to open the Spectrum Editor.

    Tip: You can also download spectrum files from the Optical Library.
  9. To orientate the image, set its Axis system by clicking one point for the origin point and two lines for X and Y directions or click and select a coordinate system to autofill the Axis System.
    Note: If you define manually one axis only, the other axis is automatically (and randomly) calculated by Speos in the 3D view. However, the other axis in the Definition panel may not correspond to the axis in the 3D view. Please refer to the axis in the 3D view.

    If you need to adjust the propagation direction of the rays, use Reverse direction.

  10. In Optional or advanced settings :
    • Adjust the Number of rays and the Length of rays to display in the 3D view.
    • If you selected an intensity distribution file, set Show Intensity Distribution to True to display the intensity diagram in the 3D view.
The Display Source is created and appears in the Simulation panel and in the 3D view.