• State Resolved
  • Locked Locked
  • Replies 17 replies
  • Answers 3 answers
  • Subscribers 35 subscribers
  • Views 6172 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

OPT8241-CDK Evaluation Module

Vasco Tesi46
Intellectual 360 points

Hello, 

a customer of us is interested in ToF technology,  I found TI implementation interesting and well documented so i will stay waiting for your CDK to be available. 

Cost nowadays is a big issue; I tried to write down a cost budget using Ti's CDK BOMs but I was not able to do this for mechanical / optical parts. 

Can someone help me ? 

thanks, bye 

  • 0
    TI__Intellectual 2030 points

    Dear Vasco,

    Thanks a lot for your interest.

    We are usually not in the best position to talk about BOM cost as we run very small volumes. Also, since this is a generic EVM and not a board meant for a specific purpose, it is best not to judge the BOM cost for your solution from this board. Having said that, there are plenty of wizard programs from various distributors which automate this task. Suggest that you try out one of those with the BOM provided in the excel format.


    For the mechanical parts, you will have to contact respective vendors.


    Regards

  • 0
    TI__Expert 3800 points
    Hi Vasco,

    For all nuts, bolts, etc we have referred to www.fastener-express.com/. However, I am sure you will be able to find a more convenient supplier for the same.
    The laser diffusers are from www.rpcphotonics.com/ . All mechanical mounting components like lens mount, diffuser holder, tripod mount, etc have been custom made by http://www.lightforcetech.com/ .
    Hope this suffices as a reference for you. Let us know if you need any other information.

    Regards

    Subhash Chandra
  • 0 in reply to Subhash Chandra Sadhu
    Intellectual 360 points

    thank you for both replies, I will ask prices to suppliers reported from you. 

  • 0 in reply to Vasco Tesi46
    TI__Intellectual 2030 points

    Dear Vasco,

    The CDK is now available here http://www.ti.com/tool/opt8241-cdk-evm#buy

    Regards

  • 0 in reply to Subhash Chandra Sadhu
    Prodigy 115 points
    Hi, Subhash!

    I have a question about diffuser for laser diode.

    In "BOM_OPT8241-CDK-EVM IB 10-50 REV2P0V1.xls" file from sbac138a.zip there is information like "...Using small EDC-80 pieces by RPC photonics" and you also said "The laser diffusers are from www.rpcphotonics.com". But on their site there is now such small diffuser as it is used in evaluation board. Moreover, they have two different EDC-80 diffusers: EDC-80-16043-E (www.rpcphotonics.com/.../) and EDC-80-12227-A (www.rpcphotonics.com/.../). I don't understand nothing in optics, but as I understand without diffuser I get strait narrow beam, just as usual laser.

    How did you made or order such small piece of diffuser? From the file "FAB-0019,Diffuser Holder, Square" we can imagine its form. Actually it has a form combine of square and cirle, right? Do you have a drawing of it?

    Or could you help me and tell, how can I get diffused light from laser diode by any other existing on the market diffusers?

    Thank you, regards!
    Aleksandr Karabatov.
  • 0 in reply to Aleksandr Karabatov
    TI__Expert 3800 points
    Hi Aleksandr,

    RPC does not sell small circular diffusers off the shelf. However, in volumes, it was possible to dice the diffusers into circles/squares per our convenience. As you have mentioned, it is possible to mount both square and circular diffusers. We have used circular diffusers.

    Regards,
    Subhash
  • 0 in reply to Subhash Chandra Sadhu
    Prodigy 115 points

    Hello! Thaks for answer!

    We are going to produce small amount of our devices, may be 100 in year. So we need to find another diffusers, I guess. What parameters should I look for when looking for a diffuser for the same diode laser?

  • 0 in reply to Aleksandr Karabatov
    TI__Expert 3800 points
    Hi Aleksandr,

    It may still be possible to have diffusers supplied in small form factor in 100s of units. I think it is best if you approach the diffuser vendor and see if it is possible.
    Please let us know if you do figure out a way to have these small form factor diffusers in 100s of units. It may help the community.

    Thanks and Regards,
    Subhash
  • 0 in reply to Subhash Chandra Sadhu
    Prodigy 115 points

    Hi, Subhash!

    PRC Photonics told me that they can't dice to a smaller pieces by their facilities. It can be done by external vendor.

    Don't you remember how have you ordered that diffusers from them?

    And question #2. Am I the only person in the internet who make ToF-camera with your chip and have problems with diffusers for laser diodes? :)

  • 0 in reply to Subhash Chandra Sadhu
    Prodigy 115 points
    And what do you think about such a construction when there is only one diffuser in 1" diameter and 4 laser diodes under it? Looks like a round table, where legs are laser diodes and the top surface is a diffuser. Is it good idea?
  • 0 in reply to Aleksandr Karabatov
    Prodigy 90 points

    Hi Aleksandr,

    You are not the one!

    I've been looking for alternatives long time.

    we replace PRC diffuser with the diffuser in Kinect 2, It seems play good.

  • 0 in reply to Aleksandr Karabatov
    TI__Intellectual 2030 points
    There is no fundamental issue with this construction. But you will need to take more care to ensure laser safety and to prove that it is safe. Also, such a design will incur more costs during production due to the larger diffuser area.

    Regards
  • 0 in reply to hangchen
    Prodigy 115 points

    RPC Photonics have agreed to slice their 2" diffusers to a small pieces like in TI's drawings.

  • 0 in reply to Bharath Patil
    Prodigy 115 points

    I have more question about construction of diffusers and diffusers itself.

    In 15345 Assembly, CDK-Illum.pdf there is a information about divergence angles of laser diode's light beam.

    I made a screenshot of the interesting area from this pdf

    If you see, you (creator of this file, TI) drew how beam from laser diode is going from laser then through first surface of diffuser (first refraction) and change its angle from 21 degree to 52, then change its angle from 52 to 87 degree by passing through second surface of diffuser.

    Here is the question#1. How did you find/get/count this angles? What is the formula to get this information?

    Moreover, diffusers from RPC Photonics is not just a piece of glass it has more complex structure. In their Fact-Sheet there is information like that:

    Divergence angle 81.7º

    Index of refraction 1.56 @ 633nm.

    .. and I don't understand what they have meant.

    Q#2: Do you understand what does this numbers mean?

  • 0 in reply to Aleksandr Karabatov
    TI__Expert 3495 points

    Best to consult RPC directly since it is their data sheet.  But it looks like divergence angle is angle at which light exits the diffuser, while index of refraction impacts angle the angle at which light propagate within the diffuser.

    https://en.wikipedia.org/wiki/Refractive_index

  • 0 in reply to Larry Li
    Prodigy 115 points

    I have one more issue with OPT8241-CDK Evaluation Module.

    One of its laser diode (D12, actually) has suddenly stopped to illuminate but the whole circuit is still working.

    Q1: Why it has happened? Your opinion or assumptions about it.

    Q2: How to avoid this problem in the future?

    Q3: Why is it still illuminating if the connection of laser diodes is made in serial not parallel?

    Thanks in advance!

    Aleksandr Karabatov

  • 0 in reply to Aleksandr Karabatov
    TI__Expert 3495 points
    A1: first it's important to make sure laser is truly not illuminating. Naked eye observation is unreliable as NIR is not very visible. If it is truly not illuminating, the likely root cause is internal bond wire failure.

    A2: if bond wire is failing you will need to contact Lumentum.

    A3: these laser diodes are 3-terminal devices, there must be an alternate path for current.