Yet another bad idea

Agro · 2019-02-21T14:26:35.000Z

Sometimes I’m wondering how to improve performance of our flashlights.
Sometimes I get ideas. Most of them are so bad that I discard them shortly.
Some are bad but I can’t see and others are setting me straight.

This one is between.
It is bad. But at the same time it’s cool so I decided to write about it anyway.

How to fit a large lens in a small host? Normally you wrap a head around the optics. But what if your TIR optics was the head? At least 2 mm diameter saving……and unique looks as well

Start with a TIR that has large aspheric in the front - so you have large diameter attachment to the body:

Glue the body to the optics base.

For bonus points add colourful aux LEDs.

You can do a similar trick with aspherics as well, glue them at the front of a thin tube.

The obvious bad thing: it will scratch and performance will degrade. Furthermore TIRs leak light to the sides which may (or may not, IDK) be blinding.

But for a show light? Why not?

Enderman · 2019-02-21T17:19:10.000Z

Yeah, the glass or plastic will chip easily if dropped on the edge.
But if you want the most throw you need to make as much of the diameter of the flashlight usable.

LouieAtienza · 2019-02-21T17:50:03.000Z

You wouldn’t need to do that. You just make a shallow curved reflector, and a lens with a reflective center, just like the Carclo optic. Thus you can make the head/reflector the integral part (like many HID spotlights are made anyway) and make the lens replaceable.

If you mold the head out of PMMA, you could likely coat the outside to prevent light leaking to the sides.

Agro · 2019-02-22T11:43:40.000Z

The idea started with performance optimization but yesterday I thought the only use would be a blingy shelf queen that sees action only occassionally and only in safe environment. Now…I think a similar but different construction may have some performance merits w/out restraining practicality but I view them as tiny.

Louie, I’m trying to imagine that Carclo head and I’m not sure if I do it correctly. You mean: a specifically designed RXI optics that has a lens (with small metallization) at the front and a separate reflector at the back?

I haven’t seen any HID searchlight let alone disassemble now. Could you describe the construction better? I would love to learn more because it doesn’t sound like a really good choice to me (as I’ll explain in a moment) and I suppose that the makers simply know this better than I do.

The way I see it now:
Lens needs to be surrounded by a metal rim to take some impact load off it. Now typically a bezel does the job. Some lights use a head for that and bezel is just a lens retaining ring.

Reflector could play that role as well but then a retaining ring (or glue) would be needed anyway.

Reflector (with a retaining ring) vs head as rim:

reflector has fewer elements around the optics which seems stronger and should enable slightly thinner edge

Reflector (with a retaining ring) vs bezel as rim:

fewer elements around the optics seems stronger
bezel can be easily made from a stronger material (titanium / steel). This is a slight weight increase but should cancel-out any mechanical advantage of reflector-rim

Notes:

I don’t like glue but it should enable small performance improvements by enabling elimination of a lens retainer and o-ring
- o-rings act as cusion in case of lens impact. Losing that cusion can’t be good
single element reflector-rim might weigh slightly less than other options
head should be a solid billet that spans all the way from the LED shelf to as far to the front as possible. So reflector-head doesn’t seem appealing
How does one manufacture such reflector? Machine exterior, anodize, machine interior, (electroform, )coat?

LouieAtienza · 2019-02-22T14:30:55.000Z

Have you ever seen an old telephoto lens? They still make them, and basically the setup is a catadioptric. The Carclo lens just adds a TIR element (actually, two TIR elements). I don’t see an issue making this out of two pieces instead of one.

The HID spotlights I refer to have what seems to be a spun and coated reflector. The aperture is threaded to allow focus against a stationary bulb. The reflectors themselves as replacement parts are not expensive, and in fact one of them made #3 on Enderman’s list, so it can’t be too bad.

Lot of concern about lens/reflector mounting. That’s thinking backwards. If you’re designing from the ground up, you first have to decide how large you want the optic to be, then figure in mounting (i.e. shelf, lip, etc.) and make it that way. If you’re doing it with an off-the shelf part it’s a different story. Even then if we know that there’s a certain amount of inaccuracy toward the farthest edge of a particular optic, you then make the conscious decision of whether to use the “usable” portion of the lens, or use the entire lens and deal with whatever anomalies you get in the beam, in exchange for a slight performance gain. There’s a difference between taking an off-the-shelf part, and getting the most out of it, versus designing something from the ground up that’s optimized for your needs.

I cannot remember the brand, but there already exists a flashlight head that has the reflector machined into it (as well as cooling fins on the exterior).

Agro · 2019-02-24T20:42:52.000Z

LouieAtienza:

Have you ever seen an old telephoto lens? They still make them, and basically the setup is a catadioptric. The Carclo lens just adds a TIR element (actually, two TIR elements). I don’t see an issue making this out of two pieces instead of one.

Yes, should be duable.

LouieAtienza:

The HID spotlights I refer to have what seems to be a spun and coated reflector. The aperture is threaded to allow focus against a stationary bulb. The reflectors themselves as replacement parts are not expensive, and in fact one of them made #3 on Enderman’s list, so it can’t be too bad.

Moon Blaster? Too bad the pics are dead.
You mean that the opening near the focal point is threaded, right?

LouieAtienza:

Lot of concern about lens/reflector mounting. That’s thinking backwards. If you’re designing from the ground up, you first have to decide how large you want the optic to be, then figure in mounting (i.e. shelf, lip, etc.) and make it that way. If you’re doing it with an off-the shelf part it’s a different story. Even then if we know that there’s a certain amount of inaccuracy toward the farthest edge of a particular optic, you then make the conscious decision of whether to use the “usable” portion of the lens, or use the entire lens and deal with whatever anomalies you get in the beam, in exchange for a slight performance gain. There’s a difference between taking an off-the-shelf part, and getting the most out of it, versus designing something from the ground up that’s optimized for your needs.

I know what I want: I want to explore the possibilities of performance improvements. I went from “what” to “how” and encountered problems that seem to be large for potential gains.

LouieAtienza:

I cannot remember the brand, but there already exists a flashlight head that has the reflector machined into it (as well as cooling fins on the exterior).

I would be so interested in seeing it…

prototype3a · 2019-02-24T20:51:31.000Z

LouieAtienza:

I cannot remember the brand, but there already exists a flashlight head that has the reflector machined into it (as well as cooling fins on the exterior).

I’ve thought about doing exactly this with a COB. If I can get a drawing from LEDiL, I may do this for the Battle Lantern.

BTW, I love your thread title. I often call my ideas “bad” or “crazy” even though they may actually be excellent ideas.