[sdiy] SMD LED intensity and lenses

[Quincas Moreira]

PWM is noooisy.....

On Wed, May 24, 2017 at 6:56 PM, Mike HEQX <mike at heqx.com> wrote:

> I would agree with pwm John, but if you have matching issues that are
> related to manufacturing variations or human perception then pwm only
> controls global brightness even if it is per color. Outside of that you
> need a physical tweak.
>
>
>
> On 5/24/2017 12:52 PM, John Speth wrote:
>
>> I think the right way to equalize LED intensity is using PWM.
>> Controlling it by varying the current will be difficult. - JJS
>>
>> -----Original Message-----
>> From: Synth-diy [mailto:synth-diy-bounces at synth-diy.org] On Behalf Of
>> Mike HEQX
>> Sent: Wednesday, May 24, 2017 7:56 AM
>> To: Rutger Vlek <rutgervlek at gmail.com>
>> Cc: synth-diy at synth-diy.org
>> Subject: Re: [sdiy] SMD LED intensity and lenses
>>
>> In that case there wont be much dispersion and absorption, which is what
>> can even out the intensity variations.
>>
>> Are you having trouble between colors or between colors and parts as well?
>>
>> Variations in color intensity can be solved, but if the components are
>> also not matched well that is more difficult.
>>
>> You might consider a diffuser disc of thin white or translucent material
>> ( like Mylar or Acrylic ) to place over the led ring under the light pipes.
>> You can also apply a color filter in this way.
>>
>> Mike
>>
>>
>> On 5/24/2017 10:43 AM, Rutger Vlek wrote:
>>
>>> Hi Mike,
>>>
>>> The light pipes are transparent with a flat 3mm diameter surface on the
>>> panel side.
>>>
>>> Rutger
>>>
>>>
>>> On 24 mei 2017, at 15:55, Mike HEQX wrote:
>>>
>>> Are your light pipes white, transparent, or translucent?
>>>>
>>>> Do they have a flat or spherical light gathering surface?
>>>>
>>>>
>>>>
>>>> On 5/24/2017 2:52 AM, Rutger Vlek wrote:
>>>>
>>>>> Hi guys/girls,
>>>>>
>>>>> I'm finishing up a new product that will contain a multi-color LED
>>>>> ring, which I plan to do with SMD leds in 4 different colors. In the
>>>>> prototype I had a hard time getting the intensities of the various colors
>>>>> of LEDs to match. I've now learned that not all manufacturers spec
>>>>> according to a comparable norm, so I've decided to stick with Kingbright
>>>>> components that at least have a reference to a uniform norm in their
>>>>> datasheets to make their reported intensities more or less comparable
>>>>> between colors and between leds. I can design in an option to regulate
>>>>> supply current to various colors individually, so technically I can
>>>>> compensate for any differences in intensity between leds.
>>>>>
>>>>> However, now I'm considering which leds to start with and have options
>>>>> for 0603 leds with a dome lens or flat lens. There will be lightpipes in
>>>>> front of the leds to bring light to the front panel, so is there any
>>>>> advantage or disadvantage to the type of lens? And more importantly, will I
>>>>> run into issues if I combine leds with a dome lens from one color (and
>>>>> spec'd brightness) with other types of lenses? I suspect the lightpipes
>>>>> will straighten out a big portion of the leds angle of dispersion, but I'm
>>>>> still hesitant to mix and match, as I feel the resulting brightness at the
>>>>> end of the lightpipe may vary.
>>>>>
>>>>> Any suggestions?
>>>>>
>>>>> Regards,
>>>>>
>>>>> Rutger
>>>>>
>>>>> ps. LED rings are cool, as are bow ties.
>>>>> _______________________________________________
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>>>>> Synth-diy at synth-diy.org
>>>>> http://synth-diy.org/mailman/listinfo/synth-diy
>>>>>
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>
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-- 
Quincas Moreira
Test Pilot at VBrazil Modular
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