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DLPC3479: Internal Pattern as actual measurement of 8bit Gray-32

Part Number: DLPC3479

Hello,

My DLP&Camera System send simultaneous trigger as shown below.

I think desired value of Gray-32(5bit plane) time is 677usec as 5400usec exposure time.

I measured actual 5bit mirror-on time by using camera exposure. However, the measured time is 634usec by shifting camera exposure delay.

Could you please let me know how to getting closer to the desired value : 677usec?

Regards,

Uryyy 

  • Uryyy,

    Are you executing this configuration on a custom DLPC3479 board or using a DLP4710-LC EVM (with the Light Control GUI)?

    If you are on the GUI, can you share your pattern configuration?

    Regards,

    Philippe Dollo

  • This measurement is on a custom DLPC3479 board. The configuration is shown as below. Also, the using pattern is displayed once.

    [The source of image]

    image_source.zip

    Regards,

    Uryyy

  • Uryyy,

    Thanks for your feedback. I will loop in the team on this issue and get you some help by early next week.

    Regards,

    Philippe Dollo

  • Hello Philippe,

    Thank you for your cooperation. I would like to know something of good ideas regarding more brightness under the same electric current.

    Regards,

    Uryyy

  • Uryyy,

    No problem. Please expect delayed response until next week due to Thanksgiving holiday.

    -Philippe

  • Hello Philippe,

    If the behavior is as specified, please explain the reason why the DMD behavior is correct.

    Regards,

    Uryyy

  • Uryyy,

    The timing distribution of the individual bit display that you have mentioned in the description is correct. But the order in which each of the 8 bits that will be displayed by the DMD may not necessarily be in the order from 0th bit to 7th bit, it can vary. Also, there are changes that the MSB bits might be displayed multiple times in a single exposure in order to cover the higher time distribution that they have. 

    I hope this will answer your query. Let me know if you have any further questions.

    Regards,

    Mayank

  • Hello Mayank,

    Thank you for your comment. Could you please provide the example of above behavior(Different order from 0bit to 7bit,Multi time's MSB)? I have understood the bitplane timing is continuous as below question.

    Regards,

    Uryyy

  • Uryyy,

    The different bits (LSB to MSB) are conveyed by the DMD as patterns which are illuminated for varying amounts of time depending on the value of the bit (for example, the MSB of a bit (7) will be displayed for the longest time while the LSB (0) will be displayed for the shortest time).

    As Mayank stated above, in some cases the larger bits (MSB) could be broken up into parts where half of bit 7 is shown at one point, and half is shown at another.

    I hope this helps explain.

    Best Regards,

    Philippe Dollo

  • Hello Philippe,

    Thank you for your explanation. Do you mean the time left(677-634=43usec) is on at another time position?

    Regards,

    Uryyy

  • Uryyy,

    The above should be the case. Can you check whether you are getting the exact 8bit pattern exposure that you are configuring the system with?

    Regards,

    Mayank

  • Hello Mayank,

    Do you mean the confirmation as 8-bit vertical or horizontal or others' configuration ?

    Regards,

    Uryyy

  • Uryyy,

    The configuration of 8bit pattern doesn't matter (can be horizontal or vertical). Just check whether you are getting light output for 5400us in this particular case, you can also verify this by measuring the duty cycle of trigger out 2 signal (with delay =0) during pattern display. 

    If this is correct, then you can conclude the individual bits of the 8bit pattern will be displayed in ratio of their binary weights.

    Regards,

    Mayank

  • Hello Mayank,

    I could have confirmed trigger out 2 = 5400usec. When camera's exposure is 5400uec, the brightness measurement is max value as below. If I can not understand your requests, please let me know the action again.

    Regards,

    Uryyy

  • Uryyy,

    Since you have confirmed that the pattern is correctly getting displayed with the exposure time that you have given as input, each bit of the 8bit pattern will be displayed for the following amount of time - ((2^x)/255)*Exposure_Time, here x is the bit position varying from 0 to 7.

    As said earlier - the order in which the individual bits of the 8 bit pattern might vary and it is possible that bits closer to MSB might get split into multiple parts.

    I hope this clarifies all your queries.

    Regards,

    Mayank