Putting Led in place of original filament lamp in an Olympus SZ1145CHI

Here you can discuss DIY adaptations to the microscope.
Post Reply
Message
Author
Milou
Posts: 165
Joined: Mon Nov 22, 2021 1:31 pm

Putting Led in place of original filament lamp in an Olympus SZ1145CHI

#1 Post by Milou » Tue Jan 10, 2023 11:12 am

Hello,
Besides my project to modify the original lighting of a Leitz SM-Lux microscope (see post below), I also want to do the same but for an Olympus SZ1145CHI which has a vertical coaxial illuminator

This one had a 6v 20W filament lamp therefore I suppose a 2-5W cree LED will be adapted?

But the light emitted by the lamp (or led) should cover a 180° angle as there are 2 light bleams starting both side of it and after two 90° angles are mixed with optical bleams coming from eyepieces and through black lens support (on the left of the 2 first picture)
See also third picture with the 2 lenses up and down of the central empty place. The original lamp and it's support are missing !
Therefore is this possible with a LED and if yes, with which kind please ?
Or another solution could be to put 2 leds back to back, therefore each one well in front a each lens?

Thank for your help

Here pictures of the vertical coaxial illuminator taken off the SZ1145 body
the lamp is placed on the right side of the picture, the 3rd picture showing a detail of this place between the 2 lenses up and down (17 mm between them)
P1100286.resized.JPG
P1100286.resized.JPG (77.77 KiB) Viewed 3951 times
P1100281.resized.JPG
P1100281.resized.JPG (95.26 KiB) Viewed 3951 times
P1100282.resized.JPG
P1100282.resized.JPG (73.12 KiB) Viewed 3951 times

Milou
Posts: 165
Joined: Mon Nov 22, 2021 1:31 pm

Re: Putting Led in place of original filament lamp in an Olympus SZ1145CHI

#2 Post by Milou » Sat Jan 14, 2023 5:34 pm

I'll try with such a G4 COB 3W LED with a 360° lighting in place of the previous halogen lamp (20W)!
Led G4 COB.resized.png
Led G4 COB.resized.png (94.61 KiB) Viewed 3837 times
But I wonder if a classical dimmer for such low voltage Led could be efficient, as it also seems there is electronic items inside this LED....

Anybody has experience of dimmable supply power for this special kind of 3W led?

User avatar
blekenbleu
Posts: 300
Joined: Tue Feb 25, 2020 5:55 pm
Location: South Carolina low country
Contact:

Re: Putting Led in place of original filament lamp in an Olympus SZ1145CHI

#3 Post by blekenbleu » Sat Jan 14, 2023 7:14 pm

Milou wrote:
Sat Jan 14, 2023 5:34 pm
I'll try with such a G4 COB 3W LED with a 360° lighting in place of the previous halogen lamp (20W)!
But I wonder if a classical dimmer for such low voltage Led could be efficient,
as it also seems there is electronic items inside this LED....
My experience has been that, if LEDs are not advertised as dimmable, then they are not.
The embedded electronics are presumably a bridge rectifier (to allow use with AC power)
and current limiting to tolerate 12-24V. Flicker may be a problem with photography.

If scopes being retrofitted lack mirrors behind their bulbs,
then 360 degree radiation will waste at least half the illumination.

FWIW, LEDs with similar image are advertised on Amazon as 2W (and dimmable):
https://www.amazon.com/dp/B09V54GG2K
Metaphot, Optiphot 1, 66; AO 10, 120, EPIStar, Cycloptic

Milou
Posts: 165
Joined: Mon Nov 22, 2021 1:31 pm

Re: Putting Led in place of original filament lamp in an Olympus SZ1145CHI

#4 Post by Milou » Sat Jan 14, 2023 7:33 pm

blekenbleu wrote:
Sat Jan 14, 2023 7:14 pm
Milou wrote:
Sat Jan 14, 2023 5:34 pm
I'll try with such a G4 COB 3W LED with a 360° lighting in place of the previous halogen lamp (20W)!
But I wonder if a classical dimmer for such low voltage Led could be efficient,
as it also seems there is electronic items inside this LED....
My experience has been that, if LEDs are not advertised as dimmable, then they are not.
The embedded electronics are presumably a bridge rectifier (to allow use with AC power)
and current limiting to tolerate 12-24V. Flicker may be a problem with photography.

If scopes being retrofitted lack mirrors behind their bulbs,
then 360 degree radiation will waste at least half the illumination.

FWIW, LEDs with similar image are advertised on Amazon as 2W (and dimmable):
https://www.amazon.com/dp/B09V54GG2K
Yes sure I'll chose dimmable G4 leds

360° led is selected as a minimum of 180° lighting angle is necessary in this case (se first post)
As there are 2 lenses both sides of the Lamp/led to light!

Scarodactyl
Posts: 2775
Joined: Sat Mar 03, 2018 9:09 pm

Re: Putting Led in place of original filament lamp in an Olympus SZ1145CHI

#5 Post by Scarodactyl » Sat Jan 14, 2023 11:23 pm

You will probably have a better time replacing the lamphouse entirely but this might give adequate results with a lot less effort.

Milou
Posts: 165
Joined: Mon Nov 22, 2021 1:31 pm

Re: Putting Led in place of original filament lamp in an Olympus SZ1145CHI

#6 Post by Milou » Sun Jan 15, 2023 8:36 am

Impossible to change this lamp housing ( a coaxial vertical illuminator ) therefore which has inside several prisms and lenses, in addition to the lenses pair placed besides lamp/led bulb!
SZ1145CHI vue.resized.png
SZ1145CHI vue.resized.png (301.93 KiB) Viewed 3767 times

Hobbyst46
Posts: 4277
Joined: Mon Aug 21, 2017 9:02 pm

Re: Putting Led in place of original filament lamp in an Olympus SZ1145CHI

#7 Post by Hobbyst46 » Sun Jan 15, 2023 11:57 am

For a back to back solution, I think I would try a pilot with small 5mm super-bright white LEDs. Such LEDs can be driven with 5 VDC, or 12 VDC or even two 2 AA batteries in series - just choose the right small (say, 1/8 W) resistor (in series with the LED). Assume that the voltage across the LED is 1.6-2 VDC and calculate the resistor to give a current of 20-50mA. Or use the LEDs specs if known. I usually buy non-branded LEDs without specs anyway.
Very easy to put the two 5mm LEDs back to back. A heat sink and dimming switch are not really needed. Just to verify the configuration. If it works, can think of two 3-5W Cree LEDs, with proper heat sinks and all.

Milou
Posts: 165
Joined: Mon Nov 22, 2021 1:31 pm

Re: Putting Led in place of original filament lamp in an Olympus SZ1145CHI

#8 Post by Milou » Sun Jan 15, 2023 12:32 pm

Thank's
You mean this kind of led:
https://fr.aliexpress.com/item/10050022 ... 2164%21rec

or this one:
https://fr.aliexpress.com/item/10050033 ... 71746406_2

as there is no room for this kind:
led dome.resized.png
led dome.resized.png (144.98 KiB) Viewed 3738 times
Indeed I could try first with that before to install more elaborated lighting also with dimmer and perhaps heat sink!

Hobbyst46
Posts: 4277
Joined: Mon Aug 21, 2017 9:02 pm

Re: Putting Led in place of original filament lamp in an Olympus SZ1145CHI

#9 Post by Hobbyst46 » Sun Jan 15, 2023 2:40 pm

Milou wrote:
Sun Jan 15, 2023 12:32 pm
Thank's
You mean this kind of led:
https://fr.aliexpress.com/item/10050022 ... 2164%21rec

or this one:
https://fr.aliexpress.com/item/10050033 ... 71746406_2

as there is no room for this kind:
led dome.resized.png

Indeed I could try first with that before to install more elaborated lighting also with dimmer and perhaps heat sink!
No, I meant this type (there are many vendors of ultra-bright or super-bright LEDs:
5mm LED.jpg
5mm LED.jpg (22.94 KiB) Viewed 3719 times
This one is taken from an Amazon listing. But they are sold on eBay and many other places. Usually not as single, rather a package of 50 or 100 yet the total cost is ~ 5$. This one is specified as 3 VDC across the LED, and 20mA working current. Usually the current can be 50 mA and even more, at least for short periods. The longer leg of the LED is the anode, connect it to the positive port of the power source. They typically provide a luminiscence of ~10-20cd. The beam angle can be 60, say (not very important since there are lenses and prisms). For me these LEDs are the easiest to fit in a wired circuit.

Milou
Posts: 165
Joined: Mon Nov 22, 2021 1:31 pm

Re: Putting Led in place of original filament lamp in an Olympus SZ1145CHI

#10 Post by Milou » Wed Feb 22, 2023 5:02 pm

At least I could managed to set a led in place of the filament lamp of origin !
As this 3 Watts led is larger then the filament lamp, I couldn't use the base where it is normally set
Therefore I've made with a small aluminium plot and 2 iron pieces a new led support (see picture)
P1100406.resized.JPG
P1100406.resized.JPG (91.83 KiB) Viewed 3244 times
I also bought a chinese power dimmable supply (see picture) very convenient with even the voltage screen display....
P1100408.resized.JPG
P1100408.resized.JPG (94.37 KiB) Viewed 3244 times

Milou
Posts: 165
Joined: Mon Nov 22, 2021 1:31 pm

Re: Putting Led in place of original filament lamp in an Olympus SZ1145CHI

#11 Post by Milou » Sat Mar 11, 2023 3:39 pm

Hello,
Has anybody has any experience with vertical coaxial illumination ?

In fact with my setup using a 3w led, the light obtained in very week on the stage and requires another light source in order to observe correctly any item! This vertical coaxial light is much too weak alone
I'm surprised by this poor result as this led (3w) is given as equivalent (in brightness) to an halogen 6volts 20 watts bulb in the origin SZ1145CHI lighting system....
All lenses are clear without any damage.....

Normally, if I'm not wrong, I think observations could be made only with the coaxial light on flats items?

Any suggestions?

jfiresto
Posts: 342
Joined: Fri Feb 15, 2019 8:19 am
Location: Northern Germany

Re: Putting Led in place of original filament lamp in an Olympus SZ1145CHI

#12 Post by jfiresto » Sat Mar 11, 2023 5:57 pm

Milou wrote:
Sat Mar 11, 2023 3:39 pm
I'm surprised by this poor result as this led (3w) is given as equivalent (in brightness) to an halogen 6volts 20 watts bulb in the origin SZ1145CHI lighting system....
Have you compared the LED's brightness outside of the microscope to a 20W incandescent bulb? Who makes the LED and does it have a technical datasheet?

I wonder about its actual wattage given the G4 form factor. I can only see perhaps 200 mm^2 of surface area to dissipate around 2W of heat which probably would not go well.

EDIT: Here is a 20W equivalent LED from OSRAM which despite being considerably larger is only rated to 40°C ambient, that is, for ventilated use in locales that do not get so hot.
-John

Milou
Posts: 165
Joined: Mon Nov 22, 2021 1:31 pm

Re: Putting Led in place of original filament lamp in an Olympus SZ1145CHI

#13 Post by Milou » Sat Mar 11, 2023 7:41 pm

jfiresto wrote:
Sat Mar 11, 2023 5:57 pm

Have you compared the LED's brightness outside of the microscope to a 20W incandescent bulb? Who makes the LED and does it have a technical datasheet?
No as I've actually no power supply for a 20W incandescent bulb!
It's a chinese led (Aliexpress) and no technical data are given about brightness aso!
https://fr.aliexpress.com/item/10050042 ... pt=glo2fra

About its actual wattage, I don't know, perhaps you're right, its too low....

I have chosen this kind of led especially for it's small size and even with this one, it was impossible to put it in the bulb base of origine!
the incandescent bulb is only 17 mm long (without pins) and leds are generally much longer......

I'll try with another G6.35 LED perhaps more powerfull!

Hobbyst46
Posts: 4277
Joined: Mon Aug 21, 2017 9:02 pm

Re: Putting Led in place of original filament lamp in an Olympus SZ1145CHI

#14 Post by Hobbyst46 » Sat Mar 11, 2023 11:05 pm

What are the specs of the power supply ? perhaps it does not deliver a sufficiently high current. Remember, the brightness of a LED directly depends on the current that flows through it, not the voltage.

User avatar
imkap
Posts: 750
Joined: Thu Nov 25, 2021 9:44 pm

Re: Putting Led in place of original filament lamp in an Olympus SZ1145CHI

#15 Post by imkap » Sun Mar 12, 2023 12:23 am

I had a similar g4 led to yours and it was declared as non dimmable, but I could easily dim it with a step down converter. I bought it locally. The other one I tried to dim the same way would start flickering instead of dimming. So best to try out, step down converters can be found cheap (few $) from China.

This is the one:
https://gradja.hr/proizvod/led-zarulja- ... 0k-commel/

Milou
Posts: 165
Joined: Mon Nov 22, 2021 1:31 pm

Re: Putting Led in place of original filament lamp in an Olympus SZ1145CHI

#16 Post by Milou » Sun Mar 12, 2023 7:47 am

@Hobbyst46
the power supply is 3V to 12V and 5 A (picture above in the file) and that's OK I think

@imkap
My G4 led is declared as dimmable and it can be easily dim with the power supply shown above. It doesn't flick

Milou
Posts: 165
Joined: Mon Nov 22, 2021 1:31 pm

Re: Putting Led in place of original filament lamp in an Olympus SZ1145CHI

#17 Post by Milou » Sun Mar 12, 2023 9:52 am

I've tried with another G6.3 led which is given for 250 - 499 Lumens and bigger then the G4 used before
P1100436.resized.JPG
P1100436.resized.JPG (78.04 KiB) Viewed 2857 times
It's lighting is already stronger as more light is transmitted and items could therefore be observed under microscope without other lighting.
But it is still "shady" and not enough clear to be comfortable only like this!

Considering G6.35 led size (30mm without pins) it is much bigger then halogen bulb and especially it's emitting filament surface (only 1 x 2 mm for this last one!)
I think all emitted led light is not transmitted by lenses on both sides of it as their diameter is small (about 11mm)...

Therefore I wonder if it is really possible to use led (always with large chips) in this special set up requiring a very restricted one?
Or perhaps with a back to back solution, using 2 small flat CREE leds whose smallest diameter seems to be around 7mm?

Post Reply