large surface LEDs
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To join, leave or search the confocal microscopy listserv, go to: http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy Post images on http://www.imgur.com and include the link in your posting. ***** Dear all, I'm looking for LED chips with high power (as those suitable for widefield fluorescence) but with a quite large emitting area (>5x5mm)? Any suggestions? Thanks! Best, Antonio Pereira i3S/IBMC, Universidade do Porto |
 
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lukas.kontenis@lightcon.com |
Re: large surface LEDs
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To join, leave or search the confocal microscopy listserv, go to: http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy Post images on http://www.imgur.com and include the link in your posting. ***** Have you considered Cree XLamp XR-E or MX-6 LEDs? They are physically large and have brightness in the 250-350 lm range, not sure if their emitter area is quite that big. Regards, Lukas Kontenis Light Conversion -----Original Message----- From: Confocal Microscopy List [mailto:[hidden email]] On Behalf Of Antonio Jose Pereira Sent: Friday, January 11, 2019 2:13 PM To: [hidden email] Subject: large surface LEDs ***** To join, leave or search the confocal microscopy listserv, go to: http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy Post images on http://www.imgur.com and include the link in your posting. ***** Dear all, I'm looking for LED chips with high power (as those suitable for widefield fluorescence) but with a quite large emitting area (>5x5mm)? Any suggestions? Thanks! Best, Antonio Pereira i3S/IBMC, Universidade do Porto |
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In reply to this post by Antonio Jose Pereira
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To join, leave or search the confocal microscopy listserv, go to: http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy Post images on http://www.imgur.com and include the link in your posting. ***** Hi Antonio, I've used Luminus LEDs in the past (https://www.luminus.com/products/white). Their single-chip LEDs have very high current density and they are very bright (look at "Specialty White LEDs"), but even the largest one (14 mm^2) is probably too small for you. Those LEDs already operate at over 20 A making the driver electronics complicated. As an alternative, Luminus (and others) also makes "COB arrays", which are much bigger, more energy-efficient (about 3x better in terms of Lumen per Watt), easier to drive (small individual chips connected in series - lower current at higher voltage), but their surface brightness is about an order of magnitude lower than the single chips... So I never really considered them for microscopy illumination (fluorescence). Best, zdenek On Fri, Jan 11, 2019 at 7:18 AM Antonio Jose Pereira <[hidden email]> wrote: > ***** > To join, leave or search the confocal microscopy listserv, go to: > http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy > Post images on http://www.imgur.com and include the link in your posting. > ***** > > Dear all, > > I'm looking for LED chips with high power (as those suitable for widefield > fluorescence) but with a quite large emitting area (>5x5mm)? > > Any suggestions? Thanks! > > Best, > > Antonio Pereira > i3S/IBMC, Universidade do Porto > -- -- Zdenek Svindrych, Ph.D. Research Associate - Imaging Specialist Department of Biochemistry and Cell Biology Geisel School of Medicine at Dartmouth |
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In reply to this post by lukas.kontenis@lightcon.com
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To join, leave or search the confocal microscopy listserv, go to: http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy Post images on http://www.imgur.com and include the link in your posting. ***** Hello, I think that the search tool provided by the component provider RS-ONLINE is powerful for this. If you go in the section visible LEDs, their website allows to filter them by size. For instance the Lumex TitanBrite with code 888-6237 are 12mmx12mm (effective 5mmx5mm) flat SMD LEDs with 800lm. There are even larger. Here the link for reference https://it.rs-online.com/web/p/led-visibili/8886237/ Regards, Diego Ulisse Pizzagalli Diego Ulisse Pizzagalli PhD Candidate and Teaching Assistant Institute for Research in Biomedicine - Bellinzona (CH) Institute of Computational Science, Universita' della Svizzera Italiana - Lugano (CH) ________________________________ Da: Confocal Microscopy List <[hidden email]> per conto di Lukas Kontenis <[hidden email]> Inviato: venerdì 11 gennaio 2019 14:32:03 A: [hidden email] Oggetto: Re: large surface LEDs ***** To join, leave or search the confocal microscopy listserv, go to: http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy Post images on http://www.imgur.com and include the link in your posting. ***** Have you considered Cree XLamp XR-E or MX-6 LEDs? They are physically large and have brightness in the 250-350 lm range, not sure if their emitter area is quite that big. Regards, Lukas Kontenis Light Conversion -----Original Message----- From: Confocal Microscopy List [mailto:[hidden email]] On Behalf Of Antonio Jose Pereira Sent: Friday, January 11, 2019 2:13 PM To: [hidden email] Subject: large surface LEDs ***** To join, leave or search the confocal microscopy listserv, go to: http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy Post images on http://www.imgur.com and include the link in your posting. ***** Dear all, I'm looking for LED chips with high power (as those suitable for widefield fluorescence) but with a quite large emitting area (>5x5mm)? Any suggestions? Thanks! Best, Antonio Pereira i3S/IBMC, Universidade do Porto |
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To join, leave or search the confocal microscopy listserv, go to: http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy Post images on http://www.imgur.com and include the link in your posting. ***** Large n x n emitters are good for flood filing a large area with light, but if you are trying to focus the light it will not be easy due to etendue issues. If you are trying to focus the light you are better off with a single emitter of the highest possible power. On the other hand, if you *are* trying to flood fill an area with light, the n x n emitters will work well, although you may need an additional diffuser to have even energy distribution across the sample. Some engineered types of diffusers are pretty good at this. Craig On Fri, Jan 11, 2019 at 8:10 AM Diego Pizzagalli <[hidden email]> wrote: > ***** > To join, leave or search the confocal microscopy listserv, go to: > http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy > Post images on http://www.imgur.com and include the link in your posting. > ***** > > Hello, > > I think that the search tool provided by the component provider RS-ONLINE > is powerful for this. > If you go in the section visible LEDs, their website allows to filter them > by size. > For instance the Lumex TitanBrite with code 888-6237 are 12mmx12mm > (effective 5mmx5mm) flat SMD LEDs with 800lm. > There are even larger. > Here the link for reference > https://it.rs-online.com/web/p/led-visibili/8886237/ > Regards, > Diego Ulisse Pizzagalli > > > > Diego Ulisse Pizzagalli > PhD Candidate and Teaching Assistant > Institute for Research in Biomedicine - Bellinzona (CH) > Institute of Computational Science, Universita' della Svizzera Italiana - > Lugano (CH) > > ________________________________ > Da: Confocal Microscopy List <[hidden email]> per conto > di Lukas Kontenis <[hidden email]> > Inviato: venerdì 11 gennaio 2019 14:32:03 > A: [hidden email] > Oggetto: Re: large surface LEDs > > ***** > To join, leave or search the confocal microscopy listserv, go to: > http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy > Post images on http://www.imgur.com and include the link in your posting. > ***** > > Have you considered Cree XLamp XR-E or MX-6 LEDs? They are physically > large and have brightness in the 250-350 lm range, not sure if their > emitter area is quite that big. > > Regards, > Lukas Kontenis > Light Conversion > > -----Original Message----- > From: Confocal Microscopy List [mailto:[hidden email]] > On Behalf Of Antonio Jose Pereira > Sent: Friday, January 11, 2019 2:13 PM > To: [hidden email] > Subject: large surface LEDs > > ***** > To join, leave or search the confocal microscopy listserv, go to: > http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy > Post images on http://www.imgur.com and include the link in your posting. > ***** > > Dear all, > > I'm looking for LED chips with high power (as those suitable for widefield > fluorescence) but with a quite large emitting area (>5x5mm)? > > Any suggestions? Thanks! > > Best, > > Antonio Pereira > i3S/IBMC, Universidade do Porto > |
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To join, leave or search the confocal microscopy listserv, go to: http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy Post images on http://www.imgur.com and include the link in your posting. ***** Thank you for the directions. Craig, it's a critical-illumination configuration that we'll have to be using. We're considering some possibilities such as a laser-illuminated dynamic diffuser as an (effective) source. Still, there seem to be also some interesting large surface LEDs around ... Let's see. Thanks! Antonio ----- Original Message ----- From: "Craig Brideau" <[hidden email]> To: "CONFOCALMICROSCOPY" <[hidden email]> Sent: Friday, 11 January, 2019 16:11:14 Subject: Re: large surface LEDs ***** To join, leave or search the confocal microscopy listserv, go to: http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy Post images on http://www.imgur.com and include the link in your posting. ***** Large n x n emitters are good for flood filing a large area with light, but if you are trying to focus the light it will not be easy due to etendue issues. If you are trying to focus the light you are better off with a single emitter of the highest possible power. On the other hand, if you *are* trying to flood fill an area with light, the n x n emitters will work well, although you may need an additional diffuser to have even energy distribution across the sample. Some engineered types of diffusers are pretty good at this. Craig On Fri, Jan 11, 2019 at 8:10 AM Diego Pizzagalli <[hidden email]> wrote: > ***** > To join, leave or search the confocal microscopy listserv, go to: > http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy > Post images on http://www.imgur.com and include the link in your posting. > ***** > > Hello, > > I think that the search tool provided by the component provider RS-ONLINE > is powerful for this. > If you go in the section visible LEDs, their website allows to filter them > by size. > For instance the Lumex TitanBrite with code 888-6237 are 12mmx12mm > (effective 5mmx5mm) flat SMD LEDs with 800lm. > There are even larger. > Here the link for reference > https://it.rs-online.com/web/p/led-visibili/8886237/ > Regards, > Diego Ulisse Pizzagalli > > > > Diego Ulisse Pizzagalli > PhD Candidate and Teaching Assistant > Institute for Research in Biomedicine - Bellinzona (CH) > Institute of Computational Science, Universita' della Svizzera Italiana - > Lugano (CH) > > ________________________________ > Da: Confocal Microscopy List <[hidden email]> per conto > di Lukas Kontenis <[hidden email]> > Inviato: venerdì 11 gennaio 2019 14:32:03 > A: [hidden email] > Oggetto: Re: large surface LEDs > > ***** > To join, leave or search the confocal microscopy listserv, go to: > http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy > Post images on http://www.imgur.com and include the link in your posting. > ***** > > Have you considered Cree XLamp XR-E or MX-6 LEDs? They are physically > large and have brightness in the 250-350 lm range, not sure if their > emitter area is quite that big. > > Regards, > Lukas Kontenis > Light Conversion > > -----Original Message----- > From: Confocal Microscopy List [mailto:[hidden email]] > On Behalf Of Antonio Jose Pereira > Sent: Friday, January 11, 2019 2:13 PM > To: [hidden email] > Subject: large surface LEDs > > ***** > To join, leave or search the confocal microscopy listserv, go to: > http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy > Post images on http://www.imgur.com and include the link in your posting. > ***** > > Dear all, > > I'm looking for LED chips with high power (as those suitable for widefield > fluorescence) but with a quite large emitting area (>5x5mm)? > > Any suggestions? Thanks! > > Best, > > Antonio Pereira > i3S/IBMC, Universidade do Porto > |
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To join, leave or search the confocal microscopy listserv, go to: http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy Post images on http://www.imgur.com and include the link in your posting. ***** I'm a big fan of critical illumination, but I can only second to Craig: a big LED won't help you. You need a bright LED! There is a pretty strict thermodynamic rule saying that you can never increase the brightness of your light source (a solid light-emitting surface) with just lenses and mirrors. More generally it has to do with the etendue mentioned by Craig. (The well known ways to get around this limitation are luminescent rod concentrators and all optically pumped lasers.) As an example, wit 1mm x 1mm LED chip the best you can do is to image it into your sample with a (hypothetical, ideal) 1:1 relay with NA=1. If you make your image larger, it's brightness will naturally go down. If you make the image smaller, then the LED-side NA of the (ideal) relay will necessarily be less than 1 and you will fail to collect all the light from the LED chip, and as a result the image brightness will NOT increase. Of course, bigger LED will make the optical design easier, but there is little benefit in sticking a 25-mm diameter LED chip right in the conjugate image plane - most of the light will be blocked by the objective back focal plane aperture (that is, miss the objective lens, and even the tube lens completely), an you would have to drive the LED at 500 Amps to get to the decent value of 1 A / mm^2 (state of the art LEDs work at 2 A / mm^2). So, 5 mm diameter LED is not a huge overkill, especially if you want to use low-magnification high-NA lenses, but with a typical 60x lens less than 2% of the total light output of the LED will be delivered to the sample. Note also, that many LEDs have a structure of electrodes on the top surface, so you may need a diffuser of some sort to blur their shadows. Best, zdenek On Fri, Jan 11, 2019 at 1:04 PM Antonio Jose Pereira <[hidden email]> wrote: > ***** > To join, leave or search the confocal microscopy listserv, go to: > http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy > Post images on http://www.imgur.com and include the link in your posting. > ***** > > Thank you for the directions. > Craig, it's a critical-illumination configuration that we'll have to be > using. We're considering some possibilities such as a laser-illuminated > dynamic diffuser as an (effective) source. Still, there seem to be also > some interesting large surface LEDs around ... Let's see. > > Thanks! > > Antonio > > ----- Original Message ----- > From: "Craig Brideau" <[hidden email]> > To: "CONFOCALMICROSCOPY" <[hidden email]> > Sent: Friday, 11 January, 2019 16:11:14 > Subject: Re: large surface LEDs > > ***** > To join, leave or search the confocal microscopy listserv, go to: > http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy > Post images on http://www.imgur.com and include the link in your posting. > ***** > > Large n x n emitters are good for flood filing a large area with light, but > if you are trying to focus the light it will not be easy due to etendue > issues. If you are trying to focus the light you are better off with a > single emitter of the highest possible power. On the other hand, if you > *are* trying to flood fill an area with light, the n x n emitters will work > well, although you may need an additional diffuser to have even energy > distribution across the sample. Some engineered types of diffusers are > pretty good at this. > > Craig > > On Fri, Jan 11, 2019 at 8:10 AM Diego Pizzagalli <[hidden email]> > wrote: > > > ***** > > To join, leave or search the confocal microscopy listserv, go to: > > http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy > > Post images on http://www.imgur.com and include the link in your > posting. > > ***** > > > > Hello, > > > > I think that the search tool provided by the component provider RS-ONLINE > > is powerful for this. > > If you go in the section visible LEDs, their website allows to filter > them > > by size. > > For instance the Lumex TitanBrite with code 888-6237 are 12mmx12mm > > (effective 5mmx5mm) flat SMD LEDs with 800lm. > > There are even larger. > > Here the link for reference > > https://it.rs-online.com/web/p/led-visibili/8886237/ > > Regards, > > Diego Ulisse Pizzagalli > > > > > > > > Diego Ulisse Pizzagalli > > PhD Candidate and Teaching Assistant > > Institute for Research in Biomedicine - Bellinzona (CH) > > Institute of Computational Science, Universita' della Svizzera Italiana - > > Lugano (CH) > > > > ________________________________ > > Da: Confocal Microscopy List <[hidden email]> per > conto > > di Lukas Kontenis <[hidden email]> > > Inviato: venerdì 11 gennaio 2019 14:32:03 > > A: [hidden email] > > Oggetto: Re: large surface LEDs > > > > ***** > > To join, leave or search the confocal microscopy listserv, go to: > > http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy > > Post images on http://www.imgur.com and include the link in your > posting. > > ***** > > > > Have you considered Cree XLamp XR-E or MX-6 LEDs? They are physically > > large and have brightness in the 250-350 lm range, not sure if their > > emitter area is quite that big. > > > > Regards, > > Lukas Kontenis > > Light Conversion > > > > -----Original Message----- > > From: Confocal Microscopy List [mailto:[hidden email]] > > On Behalf Of Antonio Jose Pereira > > Sent: Friday, January 11, 2019 2:13 PM > > To: [hidden email] > > Subject: large surface LEDs > > > > ***** > > To join, leave or search the confocal microscopy listserv, go to: > > http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy > > Post images on http://www.imgur.com and include the link in your > posting. > > ***** > > > > Dear all, > > > > I'm looking for LED chips with high power (as those suitable for > widefield > > fluorescence) but with a quite large emitting area (>5x5mm)? > > > > Any suggestions? Thanks! > > > > Best, > > > > Antonio Pereira > > i3S/IBMC, Universidade do Porto > > > -- -- Zdenek Svindrych, Ph.D. Research Associate - Imaging Specialist Department of Biochemistry and Cell Biology Geisel School of Medicine at Dartmouth |
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To join, leave or search the confocal microscopy listserv, go to: http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy Post images on http://www.imgur.com and include the link in your posting. ***** If the emitter is actually virtual points from a diffuser, wouldn't illuminating the back side of the diffuser with multiple sources increase the effective brightness of the diffuser surface? Here the limiter of brightness is the area of the diffuser, so generally pumping as much power into it as possible, even using multiple emitters, seems to make sense to me. Craig On Fri, Jan 11, 2019 at 12:28 PM Zdenek Svindrych <[hidden email]> wrote: > ***** > To join, leave or search the confocal microscopy listserv, go to: > http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy > Post images on http://www.imgur.com and include the link in your posting. > ***** > > I'm a big fan of critical illumination, but I can only second to Craig: a > big LED won't help you. You need a bright LED! > > There is a pretty strict thermodynamic rule saying that you can never > increase the brightness of your light source (a solid light-emitting > surface) with just lenses and mirrors. More generally it has to do with the > etendue mentioned by Craig. (The well known ways to get around this > limitation are luminescent rod concentrators and all optically pumped > lasers.) > > As an example, wit 1mm x 1mm LED chip the best you can do is to image it > into your sample with a (hypothetical, ideal) 1:1 relay with NA=1. If you > make your image larger, it's brightness will naturally go down. If you make > the image smaller, then the LED-side NA of the (ideal) relay will > necessarily be less than 1 and you will fail to collect all the light from > the LED chip, and as a result the image brightness will NOT increase. > > Of course, bigger LED will make the optical design easier, but there is > little benefit in sticking a 25-mm diameter LED chip right in the conjugate > image plane - most of the light will be blocked by the objective back focal > plane aperture (that is, miss the objective lens, and even the tube lens > completely), an you would have to drive the LED at 500 Amps to get to the > decent value of 1 A / mm^2 (state of the art LEDs work at 2 A / mm^2). > > So, 5 mm diameter LED is not a huge overkill, especially if you want to use > low-magnification high-NA lenses, but with a typical 60x lens less than 2% > of the total light output of the LED will be delivered to the sample. > > Note also, that many LEDs have a structure of electrodes on the top > surface, so you may need a diffuser of some sort to blur their shadows. > > Best, zdenek > > On Fri, Jan 11, 2019 at 1:04 PM Antonio Jose Pereira <[hidden email]> > wrote: > > > ***** > > To join, leave or search the confocal microscopy listserv, go to: > > http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy > > Post images on http://www.imgur.com and include the link in your > posting. > > ***** > > > > Thank you for the directions. > > Craig, it's a critical-illumination configuration that we'll have to be > > using. We're considering some possibilities such as a laser-illuminated > > dynamic diffuser as an (effective) source. Still, there seem to be also > > some interesting large surface LEDs around ... Let's see. > > > > Thanks! > > > > Antonio > > > > ----- Original Message ----- > > From: "Craig Brideau" <[hidden email]> > > To: "CONFOCALMICROSCOPY" <[hidden email]> > > Sent: Friday, 11 January, 2019 16:11:14 > > Subject: Re: large surface LEDs > > > > ***** > > To join, leave or search the confocal microscopy listserv, go to: > > http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy > > Post images on http://www.imgur.com and include the link in your > posting. > > ***** > > > > Large n x n emitters are good for flood filing a large area with light, > but > > if you are trying to focus the light it will not be easy due to etendue > > issues. If you are trying to focus the light you are better off with a > > single emitter of the highest possible power. On the other hand, if you > > *are* trying to flood fill an area with light, the n x n emitters will > work > > well, although you may need an additional diffuser to have even energy > > distribution across the sample. Some engineered types of diffusers are > > pretty good at this. > > > > Craig > > > > On Fri, Jan 11, 2019 at 8:10 AM Diego Pizzagalli < > [hidden email]> > > wrote: > > > > > ***** > > > To join, leave or search the confocal microscopy listserv, go to: > > > http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy > > > Post images on http://www.imgur.com and include the link in your > > posting. > > > ***** > > > > > > Hello, > > > > > > I think that the search tool provided by the component provider > RS-ONLINE > > > is powerful for this. > > > If you go in the section visible LEDs, their website allows to filter > > them > > > by size. > > > For instance the Lumex TitanBrite with code 888-6237 are 12mmx12mm > > > (effective 5mmx5mm) flat SMD LEDs with 800lm. > > > There are even larger. > > > Here the link for reference > > > https://it.rs-online.com/web/p/led-visibili/8886237/ > > > Regards, > > > Diego Ulisse Pizzagalli > > > > > > > > > > > > Diego Ulisse Pizzagalli > > > PhD Candidate and Teaching Assistant > > > Institute for Research in Biomedicine - Bellinzona (CH) > > > Institute of Computational Science, Universita' della Svizzera > Italiana - > > > Lugano (CH) > > > > > > ________________________________ > > > Da: Confocal Microscopy List <[hidden email]> per > > conto > > > di Lukas Kontenis <[hidden email]> > > > Inviato: venerdì 11 gennaio 2019 14:32:03 > > > A: [hidden email] > > > Oggetto: Re: large surface LEDs > > > > > > ***** > > > To join, leave or search the confocal microscopy listserv, go to: > > > http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy > > > Post images on http://www.imgur.com and include the link in your > > posting. > > > ***** > > > > > > Have you considered Cree XLamp XR-E or MX-6 LEDs? They are physically > > > large and have brightness in the 250-350 lm range, not sure if their > > > emitter area is quite that big. > > > > > > Regards, > > > Lukas Kontenis > > > Light Conversion > > > > > > -----Original Message----- > > > From: Confocal Microscopy List [mailto: > [hidden email]] > > > On Behalf Of Antonio Jose Pereira > > > Sent: Friday, January 11, 2019 2:13 PM > > > To: [hidden email] > > > Subject: large surface LEDs > > > > > > ***** > > > To join, leave or search the confocal microscopy listserv, go to: > > > http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy > > > Post images on http://www.imgur.com and include the link in your > > posting. > > > ***** > > > > > > Dear all, > > > > > > I'm looking for LED chips with high power (as those suitable for > > widefield > > > fluorescence) but with a quite large emitting area (>5x5mm)? > > > > > > Any suggestions? Thanks! > > > > > > Best, > > > > > > Antonio Pereira > > > i3S/IBMC, Universidade do Porto > > > > > > > > -- > -- > Zdenek Svindrych, Ph.D. > Research Associate - Imaging Specialist > Department of Biochemistry and Cell Biology > Geisel School of Medicine at Dartmouth > |
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To join, leave or search the confocal microscopy listserv, go to: http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy Post images on http://www.imgur.com and include the link in your posting. ***** In terms of sheer power density, these LEDs are second to none: https://download.luminus.com/datasheets/Luminus_CBT-90_Datasheet.pdf For example, the blue LED emits 10.5W at 13.5 A out of a 3 mm x 3 mm die. At the maximum CW current (27A) you then get 16W optical output. To catch all the light and get a perfectly uniform field of illumination, just setup a Köhler light path, which only takes 4 lenses, so it is pretty cheap to do. If you are porting the light into a microscope, it will already be setup for Köhler illumination, so then just collimate the light using a cheap asphere condenser lens and you are good to go, no diffusers needed. We currently are using the blue LED in one of our setups. The measured output of the LED at the sample plane is 5x brighter than a mercury arc lamp. To cool it we simply bolted it onto a CPU fan, which turned out to be massive overkill, but I guess that isn't a bad thing: http://bit.ly/2H7nqlV As a bonus the COB includes a thermistor, so you can monitor the temperature of the LED in real time. We use an Arduino to track the LED temp, and it ramps up the CPU fan (using PWM) as the chip heats up, and will shut off the LED driver if the LED gets too warm. Hope this helps, Ben Smith On Fri, Jan 11, 2019 at 11:48 AM Craig Brideau <[hidden email]> wrote: > ***** > To join, leave or search the confocal microscopy listserv, go to: > http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy > Post images on http://www.imgur.com and include the link in your posting. > ***** > > If the emitter is actually virtual points from a diffuser, wouldn't > illuminating the back side of the diffuser with multiple sources increase > the effective brightness of the diffuser surface? Here the limiter of > brightness is the area of the diffuser, so generally pumping as much power > into it as possible, even using multiple emitters, seems to make sense to > me. > > Craig > > On Fri, Jan 11, 2019 at 12:28 PM Zdenek Svindrych <[hidden email]> > wrote: > > > ***** > > To join, leave or search the confocal microscopy listserv, go to: > > http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy > > Post images on http://www.imgur.com and include the link in your > posting. > > ***** > > > > I'm a big fan of critical illumination, but I can only second to Craig: a > > big LED won't help you. You need a bright LED! > > > > There is a pretty strict thermodynamic rule saying that you can never > > increase the brightness of your light source (a solid light-emitting > > surface) with just lenses and mirrors. More generally it has to do with > the > > etendue mentioned by Craig. (The well known ways to get around this > > limitation are luminescent rod concentrators and all optically pumped > > lasers.) > > > > As an example, wit 1mm x 1mm LED chip the best you can do is to image it > > into your sample with a (hypothetical, ideal) 1:1 relay with NA=1. If you > > make your image larger, it's brightness will naturally go down. If you > make > > the image smaller, then the LED-side NA of the (ideal) relay will > > necessarily be less than 1 and you will fail to collect all the light > from > > the LED chip, and as a result the image brightness will NOT increase. > > > > Of course, bigger LED will make the optical design easier, but there is > > little benefit in sticking a 25-mm diameter LED chip right in the > conjugate > > image plane - most of the light will be blocked by the objective back > focal > > plane aperture (that is, miss the objective lens, and even the tube lens > > completely), an you would have to drive the LED at 500 Amps to get to the > > decent value of 1 A / mm^2 (state of the art LEDs work at 2 A / mm^2). > > > > So, 5 mm diameter LED is not a huge overkill, especially if you want to > use > > low-magnification high-NA lenses, but with a typical 60x lens less than > 2% > > of the total light output of the LED will be delivered to the sample. > > > > Note also, that many LEDs have a structure of electrodes on the top > > surface, so you may need a diffuser of some sort to blur their shadows. > > > > Best, zdenek > > > > On Fri, Jan 11, 2019 at 1:04 PM Antonio Jose Pereira < > [hidden email]> > > wrote: > > > > > ***** > > > To join, leave or search the confocal microscopy listserv, go to: > > > http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy > > > Post images on http://www.imgur.com and include the link in your > > posting. > > > ***** > > > > > > Thank you for the directions. > > > Craig, it's a critical-illumination configuration that we'll have to be > > > using. We're considering some possibilities such as a laser-illuminated > > > dynamic diffuser as an (effective) source. Still, there seem to be also > > > some interesting large surface LEDs around ... Let's see. > > > > > > Thanks! > > > > > > Antonio > > > > > > ----- Original Message ----- > > > From: "Craig Brideau" <[hidden email]> > > > To: "CONFOCALMICROSCOPY" <[hidden email]> > > > Sent: Friday, 11 January, 2019 16:11:14 > > > Subject: Re: large surface LEDs > > > > > > ***** > > > To join, leave or search the confocal microscopy listserv, go to: > > > http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy > > > Post images on http://www.imgur.com and include the link in your > > posting. > > > ***** > > > > > > Large n x n emitters are good for flood filing a large area with light, > > but > > > if you are trying to focus the light it will not be easy due to etendue > > > issues. If you are trying to focus the light you are better off with a > > > single emitter of the highest possible power. On the other hand, if you > > > *are* trying to flood fill an area with light, the n x n emitters will > > work > > > well, although you may need an additional diffuser to have even energy > > > distribution across the sample. Some engineered types of diffusers are > > > pretty good at this. > > > > > > Craig > > > > > > On Fri, Jan 11, 2019 at 8:10 AM Diego Pizzagalli < > > [hidden email]> > > > wrote: > > > > > > > ***** > > > > To join, leave or search the confocal microscopy listserv, go to: > > > > http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy > > > > Post images on http://www.imgur.com and include the link in your > > > posting. > > > > ***** > > > > > > > > Hello, > > > > > > > > I think that the search tool provided by the component provider > > RS-ONLINE > > > > is powerful for this. > > > > If you go in the section visible LEDs, their website allows to filter > > > them > > > > by size. > > > > For instance the Lumex TitanBrite with code 888-6237 are 12mmx12mm > > > > (effective 5mmx5mm) flat SMD LEDs with 800lm. > > > > There are even larger. > > > > Here the link for reference > > > > https://it.rs-online.com/web/p/led-visibili/8886237/ > > > > Regards, > > > > Diego Ulisse Pizzagalli > > > > > > > > > > > > > > > > Diego Ulisse Pizzagalli > > > > PhD Candidate and Teaching Assistant > > > > Institute for Research in Biomedicine - Bellinzona (CH) > > > > Institute of Computational Science, Universita' della Svizzera > > Italiana - > > > > Lugano (CH) > > > > > > > > ________________________________ > > > > Da: Confocal Microscopy List <[hidden email]> per > > > conto > > > > di Lukas Kontenis <[hidden email]> > > > > Inviato: venerdì 11 gennaio 2019 14:32:03 > > > > A: [hidden email] > > > > Oggetto: Re: large surface LEDs > > > > > > > > ***** > > > > To join, leave or search the confocal microscopy listserv, go to: > > > > http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy > > > > Post images on http://www.imgur.com and include the link in your > > > posting. > > > > ***** > > > > > > > > Have you considered Cree XLamp XR-E or MX-6 LEDs? They are physically > > > > large and have brightness in the 250-350 lm range, not sure if their > > > > emitter area is quite that big. > > > > > > > > Regards, > > > > Lukas Kontenis > > > > Light Conversion > > > > > > > > -----Original Message----- > > > > From: Confocal Microscopy List [mailto: > > [hidden email]] > > > > On Behalf Of Antonio Jose Pereira > > > > Sent: Friday, January 11, 2019 2:13 PM > > > > To: [hidden email] > > > > Subject: large surface LEDs > > > > > > > > ***** > > > > To join, leave or search the confocal microscopy listserv, go to: > > > > http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy > > > > Post images on http://www.imgur.com and include the link in your > > > posting. > > > > ***** > > > > > > > > Dear all, > > > > > > > > I'm looking for LED chips with high power (as those suitable for > > > widefield > > > > fluorescence) but with a quite large emitting area (>5x5mm)? > > > > > > > > Any suggestions? Thanks! > > > > > > > > Best, > > > > > > > > Antonio Pereira > > > > i3S/IBMC, Universidade do Porto > > > > > > > > > > > > > -- > > -- > > Zdenek Svindrych, Ph.D. > > Research Associate - Imaging Specialist > > Department of Biochemistry and Cell Biology > > Geisel School of Medicine at Dartmouth > > > -- Benjamin E. Smith, Ph. D. Imaging Specialist, Vision Science University of California, Berkeley 195 Life Sciences Addition Berkeley, CA 94720-3200 Tel (510) 642-9712 Fax (510) 643-6791 e-mail: [hidden email] http://vision.berkeley.edu/?page_id=5635 <http://vision.berkeley.edu/> |
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To join, leave or search the confocal microscopy listserv, go to: http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy Post images on http://www.imgur.com and include the link in your posting. ***** I would generally agree Ben, if this was for conventional microscopy, but in this experiment where we are forbidden to do Kohler. It's as if I were interested in imaging the LED chip structure itself. @Zdenek and Craig, good that you brought up these important étendue issues. We're actually interested in decreasing the number of modes (proportional to the étendue) that manage to enter the optical system in our particular experiment. I was just considering (with the help of the Van Cittert-Zernike theorem...) using a larger incoherent source to, at the cost of power as you mention very clearly by the way, increment spatial coherence at a given pupil at a given distance. But anyway I agree there are degrees of freedom around to prevent using a large area source. I just have to check how free those degrees are to me. Antonio ----- Original Message ----- From: "Benjamin Smith" <[hidden email]> To: "CONFOCALMICROSCOPY" <[hidden email]> Sent: Friday, 11 January, 2019 22:33:32 Subject: Re: large surface LEDs ***** To join, leave or search the confocal microscopy listserv, go to: http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy Post images on http://www.imgur.com and include the link in your posting. ***** In terms of sheer power density, these LEDs are second to none: https://download.luminus.com/datasheets/Luminus_CBT-90_Datasheet.pdf For example, the blue LED emits 10.5W at 13.5 A out of a 3 mm x 3 mm die. At the maximum CW current (27A) you then get 16W optical output. To catch all the light and get a perfectly uniform field of illumination, just setup a Köhler light path, which only takes 4 lenses, so it is pretty cheap to do. If you are porting the light into a microscope, it will already be setup for Köhler illumination, so then just collimate the light using a cheap asphere condenser lens and you are good to go, no diffusers needed. We currently are using the blue LED in one of our setups. The measured output of the LED at the sample plane is 5x brighter than a mercury arc lamp. To cool it we simply bolted it onto a CPU fan, which turned out to be massive overkill, but I guess that isn't a bad thing: http://bit.ly/2H7nqlV As a bonus the COB includes a thermistor, so you can monitor the temperature of the LED in real time. We use an Arduino to track the LED temp, and it ramps up the CPU fan (using PWM) as the chip heats up, and will shut off the LED driver if the LED gets too warm. Hope this helps, Ben Smith On Fri, Jan 11, 2019 at 11:48 AM Craig Brideau <[hidden email]> wrote: > ***** > To join, leave or search the confocal microscopy listserv, go to: > http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy > Post images on http://www.imgur.com and include the link in your posting. > ***** > > If the emitter is actually virtual points from a diffuser, wouldn't > illuminating the back side of the diffuser with multiple sources increase > the effective brightness of the diffuser surface? Here the limiter of > brightness is the area of the diffuser, so generally pumping as much power > into it as possible, even using multiple emitters, seems to make sense to > me. > > Craig > > On Fri, Jan 11, 2019 at 12:28 PM Zdenek Svindrych <[hidden email]> > wrote: > > > ***** > > To join, leave or search the confocal microscopy listserv, go to: > > http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy > > Post images on http://www.imgur.com and include the link in your > posting. > > ***** > > > > I'm a big fan of critical illumination, but I can only second to Craig: a > > big LED won't help you. You need a bright LED! > > > > There is a pretty strict thermodynamic rule saying that you can never > > increase the brightness of your light source (a solid light-emitting > > surface) with just lenses and mirrors. More generally it has to do with > the > > etendue mentioned by Craig. (The well known ways to get around this > > limitation are luminescent rod concentrators and all optically pumped > > lasers.) > > > > As an example, wit 1mm x 1mm LED chip the best you can do is to image it > > into your sample with a (hypothetical, ideal) 1:1 relay with NA=1. If you > > make your image larger, it's brightness will naturally go down. If you > make > > the image smaller, then the LED-side NA of the (ideal) relay will > > necessarily be less than 1 and you will fail to collect all the light > from > > the LED chip, and as a result the image brightness will NOT increase. > > > > Of course, bigger LED will make the optical design easier, but there is > > little benefit in sticking a 25-mm diameter LED chip right in the > conjugate > > image plane - most of the light will be blocked by the objective back > focal > > plane aperture (that is, miss the objective lens, and even the tube lens > > completely), an you would have to drive the LED at 500 Amps to get to the > > decent value of 1 A / mm^2 (state of the art LEDs work at 2 A / mm^2). > > > > So, 5 mm diameter LED is not a huge overkill, especially if you want to > use > > low-magnification high-NA lenses, but with a typical 60x lens less than > 2% > > of the total light output of the LED will be delivered to the sample. > > > > Note also, that many LEDs have a structure of electrodes on the top > > surface, so you may need a diffuser of some sort to blur their shadows. > > > > Best, zdenek > > > > On Fri, Jan 11, 2019 at 1:04 PM Antonio Jose Pereira < > [hidden email]> > > wrote: > > > > > ***** > > > To join, leave or search the confocal microscopy listserv, go to: > > > http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy > > > Post images on http://www.imgur.com and include the link in your > > posting. > > > ***** > > > > > > Thank you for the directions. > > > Craig, it's a critical-illumination configuration that we'll have to be > > > using. We're considering some possibilities such as a laser-illuminated > > > dynamic diffuser as an (effective) source. Still, there seem to be also > > > some interesting large surface LEDs around ... Let's see. > > > > > > Thanks! > > > > > > Antonio > > > > > > ----- Original Message ----- > > > From: "Craig Brideau" <[hidden email]> > > > To: "CONFOCALMICROSCOPY" <[hidden email]> > > > Sent: Friday, 11 January, 2019 16:11:14 > > > Subject: Re: large surface LEDs > > > > > > ***** > > > To join, leave or search the confocal microscopy listserv, go to: > > > http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy > > > Post images on http://www.imgur.com and include the link in your > > posting. > > > ***** > > > > > > Large n x n emitters are good for flood filing a large area with light, > > but > > > if you are trying to focus the light it will not be easy due to etendue > > > issues. If you are trying to focus the light you are better off with a > > > single emitter of the highest possible power. On the other hand, if you > > > *are* trying to flood fill an area with light, the n x n emitters will > > work > > > well, although you may need an additional diffuser to have even energy > > > distribution across the sample. Some engineered types of diffusers are > > > pretty good at this. > > > > > > Craig > > > > > > On Fri, Jan 11, 2019 at 8:10 AM Diego Pizzagalli < > > [hidden email]> > > > wrote: > > > > > > > ***** > > > > To join, leave or search the confocal microscopy listserv, go to: > > > > http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy > > > > Post images on http://www.imgur.com and include the link in your > > > posting. > > > > ***** > > > > > > > > Hello, > > > > > > > > I think that the search tool provided by the component provider > > RS-ONLINE > > > > is powerful for this. > > > > If you go in the section visible LEDs, their website allows to filter > > > them > > > > by size. > > > > For instance the Lumex TitanBrite with code 888-6237 are 12mmx12mm > > > > (effective 5mmx5mm) flat SMD LEDs with 800lm. > > > > There are even larger. > > > > Here the link for reference > > > > https://it.rs-online.com/web/p/led-visibili/8886237/ > > > > Regards, > > > > Diego Ulisse Pizzagalli > > > > > > > > > > > > > > > > Diego Ulisse Pizzagalli > > > > PhD Candidate and Teaching Assistant > > > > Institute for Research in Biomedicine - Bellinzona (CH) > > > > Institute of Computational Science, Universita' della Svizzera > > Italiana - > > > > Lugano (CH) > > > > > > > > ________________________________ > > > > Da: Confocal Microscopy List <[hidden email]> per > > > conto > > > > di Lukas Kontenis <[hidden email]> > > > > Inviato: venerdì 11 gennaio 2019 14:32:03 > > > > A: [hidden email] > > > > Oggetto: Re: large surface LEDs > > > > > > > > ***** > > > > To join, leave or search the confocal microscopy listserv, go to: > > > > http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy > > > > Post images on http://www.imgur.com and include the link in your > > > posting. > > > > ***** > > > > > > > > Have you considered Cree XLamp XR-E or MX-6 LEDs? They are physically > > > > large and have brightness in the 250-350 lm range, not sure if their > > > > emitter area is quite that big. > > > > > > > > Regards, > > > > Lukas Kontenis > > > > Light Conversion > > > > > > > > -----Original Message----- > > > > From: Confocal Microscopy List [mailto: > > [hidden email]] > > > > On Behalf Of Antonio Jose Pereira > > > > Sent: Friday, January 11, 2019 2:13 PM > > > > To: [hidden email] > > > > Subject: large surface LEDs > > > > > > > > ***** > > > > To join, leave or search the confocal microscopy listserv, go to: > > > > http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy > > > > Post images on http://www.imgur.com and include the link in your > > > posting. > > > > ***** > > > > > > > > Dear all, > > > > > > > > I'm looking for LED chips with high power (as those suitable for > > > widefield > > > > fluorescence) but with a quite large emitting area (>5x5mm)? > > > > > > > > Any suggestions? Thanks! > > > > > > > > Best, > > > > > > > > Antonio Pereira > > > > i3S/IBMC, Universidade do Porto > > > > > > > > > > > > > -- > > -- > > Zdenek Svindrych, Ph.D. > > Research Associate - Imaging Specialist > > Department of Biochemistry and Cell Biology > > Geisel School of Medicine at Dartmouth > > > -- Benjamin E. Smith, Ph. D. Imaging Specialist, Vision Science University of California, Berkeley 195 Life Sciences Addition Berkeley, CA 94720-3200 Tel (510) 642-9712 Fax (510) 643-6791 e-mail: [hidden email] http://vision.berkeley.edu/?page_id=5635 <http://vision.berkeley.edu/> |
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