Defining a HUD System with HUD Optical Design

The following procedure helps you define a HUD Optical Design (HOD) to create the optical system for a HUD system.

To define a HUD Optical Design system:

  1. In the Design tab, in the Optical Part Design section, click HUD Optical Design .
  2. In the General section, if you want to define a custom axis system for the vehicle, define the Vehicle Direction and the Top Direction.
    1. Click and select a line to define the vehicle direction.
    2. Click and select a line to define the top direction.
    For more information on the axis system, refer to General.
  3. In the Eyebox section, click Center of eyebox and select a center for the eyebox in the 3D view.
    For more information on the Eyebox, refer to Eyebox.
  4. In Orientation, define the vertical direction of the Eyebox:
    • Select Normal to optical axis to set the vertical direction as normal to the optical axis defined thanks to the Target Image section.
    • Select Normal to vehicle axis to set the vertical direction as normal to the vehicle axis defined in the General section.
  5. Define the Horizontal size and Vertical size of the eyebox.
  6. Define the Horizontal sampling and Vertical sampling of the eyebox.
    The resolution is automatically computed.
  7. In Position Direction, define the direction used to apply the offsets:
    • Select Normal to central eyebox optical axis to set the position direction as normal to the nominal driver optical axis defined thanks to the Target Image section.
    • Select Normal to vehicle axis to set the position direction as normal to the vehicle axis defined in the General section.
  8. If you want to create a multi-driver configuration and create several eyeboxes to analyze the system, In the Eyebox configurations table, click Add .
    1. Define their Name and Offset.
      The default eyebox or nominal eyebox corresponds to the Central eyebox with a 0mm-offset. Each added eyebox is created with respect to the nominal eyebox at a distance corresponding to the offset.
    2. In Weight, specify the importance of each eyebox in the HUD system. The weight is used to indicate the importance of each eyebox in the results.
  9. In the Target Image section, in Virtual Image Distance specify the distance between the center of the nominal Eyebox and the center of the Target Image.
    For more information on the Target Image, refer to Target Image.
  10. Set the Look Over Angle (horizontal angle) between the vehicle axis and the optical axis.
    Note: To define the optical axis, HUD Optical Design applies first the Look Over Angle, then the Look Down Angle.
  11. Set the Look Down Angle (vertical angle) between the vehicle axis and the optical axis.
  12. In Mode specify the mode used to define the Target Image:
    • Select Size and define the Horizontal size and Vertical size of the Target Image in millimeters.
    • Select Field Of View and define the Horizontal Field of view and Vertical field of view of the Target Image in degrees.
  13. In the Windshield section, click and select the inner surface of the windshield in the 3D view.
    Note: A face or a multifaces body can be selected as surface.
    Note: Faceted geometries (such as imported *.stl files or other file formats alike) can be used as input geometry.
  14. In the Projectors table, click to create new mirrors. For each element of the table:
    1. In the Projector type column, select Freeform mirror to create a mirror used for the optimization, or Fold mirror to create a mirror used to reduce the volume of the projector
    2. In the Distance column, define the distance separating the mirror from the previous element.
    3. In Horizontal angle and Vertical angle, define the angles corresponding to the orientation of the element in the global axis system.
    Note: The order of the elements in the table considers the optical path from the windshield towards the Picture Generation Unit (PGU). The bottom line of the table is always the PGU.

    When designing the system, a preview indicates if the construction is correct or not. A green display means the elements can be computed without error. A red display means one or more elements cannot be computed.

    A green display does not mean relevant results. It only means that the system is considered as correctly defined.

    For more information on the Projector, refer to Projector.
  15. In the PGU section, define the characteristics of the PGU:

    • Select a predefined PGU among the available models.

      The name corresponds to the characteristics of the PGU. Example: 1.8" = size (in inches), 2:1 = horizontal to vertical size ratio of the screen, 480x240 = PGU pixel resolution.

    • Select User Defined and manually define the Horizontal and Vertical sizes of the PGU in millimeters, and the Horizontal and Vertical resolutions in pixel.
  16. In the Manufacturing section, define the X degree and Y degree of polynomial equation used to design the mirrors.
    For more information on the Manufacturing, refer to Manufacturing.
  17. In the Advanced Parameters section, if you want to maximize, optimize or adjust your HUD system, you can define:
    • the Mirror Size Ratio to optimize the mirror's size according to how the HUD system has been designed.
    • the PGU Usage to adjust the ratio between the warping and the Picture Generation Unit to optimize the surface used by the warping.
    • the Stopping Criterion to define a threshold value representing the degree of precision to be reached for the optimization to end.
    • the Curvature Balance to pilot the curvature of the first freeform mirror to get the best image quality.
    For more information on the Advanced parameters, refer to Advanced Parameters.
  18. If you want, click Precompute Head Up Display to help determine the best optical path to choose.

    The optical path (position and orientation of mirrors) is optimized to reach the best optical quality for the virtual image while using the maximum surface of the PGU. However, the Layout Optimization does not take into account the potential hiding or intersection between mirrors. Therefore, in some case, the PGU could be place behind a freeform mirror. To overcome the issue, you can manually adjust the position and orientation of the PGU.

    For more information, refer to Precompute Option.

    Note: Precompute Head Up Display only supports one Freeform mirror. For multi-freeform mirrors, use Compute.
  19. Click Compute to optimize the HUD system.
    Once the HOD optimization is done, the computed surfaces appear in the 3D view.