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DLP LightCraft 4500 projection angle

Kurt Lauer
Prodigy 20 points

Can anyone supply me with the projection angle of a DLP LightCraft 4500 in both X and Y, X being the long axis of the unit and Y being the shorter?

Thank you,

Kurt

  • 0
    TI__Mastermind 30600 points
    Hi Kurt,

    Welcome to the DLP forums and thank you for your question. If you look at pages 22 and 23 of the data sheet (section 7.3 Feature Description), you'll see how the incident illumination should land on the device. Section 6.9 shows the physical dimensions of the array.

    www.ti.com/.../dlp4500.pdf

    I hope that helps. Let me know if you have any other questions.
    -Paul
  • 0 in reply to Paul Goedeke
    Prodigy 20 points
    Hi Paul,

    Thank you for the information but it is all Greek to me. Am I correct in assuming that if I drew a pyramid coming out of the lens with an inclusive angle of 24 degrees, this would give me my projection field? I'm ultimately trying to find the distance from object to lens to produce a 36" square projection.

    Kurt
  • 0 in reply to Kurt Lauer
    TI__Mastermind 48520 points

    Hello Kurt,

    I am going to jump in here on this. 

    To clarify, you are wanting a 36" x 36" projected area from the projector.  For the standard DLP LightCrafter4500, therefore you are interested in the vertical size.  In the horizontal you will need to project dark bands on the side to make a width of 36".

    The EVMs vary from unit to unit, but on measurements done on a LightCrafter4500 an estimated distance of 50-60" will give a vertical image height around 36".

    What you are looking for is called throw ratio. It is generally defined in the horizontal direction.  The data sheet for the LightCrafer4500 shows 1.4, but we measure closer to 1.2.  A horizontal throw ratio can be converted to a vertical by dividing by the Aspect Ratio (i.e. 1.2/(16/10) ≈ 0.75).

    This is very easy to measure and is quite linear.  Put the projector at some distance s (say 15") and measure the height, then at 2s (30") and measure the height.  Plot image height vs distance and find where the line reaches 36" height and the distance will be the x coordinate of that spot.

    If you want to check the linearity you could make a third measurement at 3s and plot it also.

    I hope this helps.

    Fizix