Projector study pics ( too many pics..not much explain..sorry!)

[upashi]

I found my old projector study pics and video in my computer.

I really not sure where to post or who interested in, if anyone interested in or found this useful, move to wherever appropriate thread group please.



Ok, here is start point.

have you ever wondered looking at beam projection pattern from projector onto headlight lens..."it's kinda wired shape, how this develop into wide beam pattern?"
"Which part is reflected by which part of bowl? "etc..


So I did test.

I used Acura MDX h11 halogen projector for testing.
Typical Koito H11 halogen projector.

I would say most of projector bowl can be broke down into 3 section( some has 4 block, some has more complicated structure )
Analyzing by simplified concept should give us general idea of how beam pattern mix is processed.


First, I labeled top half of bowl as A, left bottom(looking into bowl) as B and right bottom as C




Then tested how each section of bowl correspond to output pattern. I used masking tape to cover section.(it worked pretty well!)



Here is output pattern from section A only



Looks like most of beam pattern general shape is formed by top half of reflector bowl.



Output pattern from section B only




Output pattern from section C only



looks like bottom half of bowl giving "along cut-off"' line focus and side stretch.


This is B+C bottom half output










Next part is how each beam pattern shoot out from projector lens and how it develops over distance.

A only



B only



C only




Small dots looking lights is from block patterned part of bowl. This part mostly go through rectangular finder to light up signs etc..
And look like bottom front of bowl, where wave groove are formed is the part isn't used as light output.







Next is movie clips for top and bottom beam pattern development over distance.

top only( A)




Bottom only( B+C)





And here is A+B+C




I removed cut-off shield to see how beam mix changes compare to one above.

A=B+C without cut-off shield





This is bottom half(B+C) without cut-off shield







Extra tests,

I had clear, Fresnel and frost lens for this projector.









Hope someone find this somewhat useful when modifying projector/bowl!

[ChrisMan287]

Nice findings! I've always wondered how the bowls exactly worked.

[Tyutyunnik]

Brings me back to physics class, I swear there should be a sticky about lens optics on this forum, physics explains everything!

Very interesting stuff OP!

[badbadtz560]

sounds like what I was planning to do w/ my "spare" mh1 Was looking to purposely reduce reflectivity of certain parts of the bowl-chrome in order to reduce the foreground lighting and control the laser beams rather than eliminating portions of it via a foreground limiter on the shield.

question for ya - you taped masking tape directly on the bowl and it didn't ruin any of the chrome or get any burn marks?

[upashi]

It was my experimental unit, so yes, I just slap blue masking tape directly onto deposition surface.
Non of surface finish came off. I run halogen bulb at lower voltage to test beam paattern, so no burn mark either.

I did this onto TSX projector as well and surface finish didn't get damaged either(at least visibly)

Here is TSX distribution mix.





This is 4 block projector bowl distribution pattern. Compare to uni-surface type bowl, it can use block a and b part bit more controlably.

Although, there is general theory how beam can be mixed, you need to experiment with each projector of course.
If you are thinking to create limiter at projector bowl level, try experiment based on TSX block e equivalent area on your projector.

[StupidPig]

This should definitely go to University section. Nice job!

[luvlexus101]

Impressive.

[gold94corolla]

Nice job, I love it! I see these pictures being used many times for years to come...

[upashi]

Just opened up 2015 Mazda3 and extract H11 halognen projector.

Pretty standard halogen projector I think.
But since I had parts on my hand,,, let's take a look bit.

Projector lens has small flat cut surface at bottom 6 o'clock position.
This was actually making "above cut off" slight illumination for lighting up street signs. Function wise, same concept as "squirrel finder"



to the left is the projector I observed ( from 2015 Mazda 3 H11 halogen projector)





reflector bowl has cut out on top and flat surface at bottom, with few surfaces.




I labeled A to I for each section.




Looks like only A1, A2 and C portion is outputting light.
All other section didn't make any visible difference in beam output.

A2 and A1 is continuous smooth surface, but curve parameter is definitely different, so I labeled separately.



C is the portion making "above cut off" illumination.


In below picture, filament image on C also reflect onto D
But due to shield design, that specific angle does not output.




When I covered C, filament image does not show on D





C image will go through bottom opening of shield, and enter at the bottom of projector lens, that has flat cut surface on front side.


This portion of output develop into "above cut off" illumination.






At certain angle, I could observe B image onto H surface, but this angle will be blocked by shield, so no output.
So just a structural design



section I is textured, either diffuse to blend filament holding wire shadow, or to avoid unbalanced output distribution at lower beam center.
(as RH and LH of A1 section kinda cross merge image. By having textured portion, avoid overlap distribution intensity balance.)


F and G were completely useless. It reflect light source at large angle, blocked by shield.



A1 and A2 create beam, I to soften beam lower center illumination, C for above cut off illumination.

All other section, = useless optically, just structural design.


To block "squirrel finder' on this projector, cover bottom opening of shield.

[NewShockerGuy]

Old thread but lots of great info in this post. Question for you

Your picture of this:

I see different projectors have different amount of straight lines and some even have a checkered patter and lines at the bottom. There doesn't seem to be a "standard" set of lines. Does or does this not affect light output down the road? IE: One with the entire bottom portion of the projector bowl that has lines compared to one that doesn't which will have a greater output of light?

Thanks,
-Nigel

[upashi]

Bottom portion with those lines, for example, MDX projector you linked, entirely NOT contributing output.
If you trim out entire rib?(line) textured bottom portion in that picture, and you will have same low beam output in this projector.

In other word, you could use this area to "recycle " wasted light into something supplemental, such as LS430 sub reflector kind projector. (
their system use upper portion's unwanted surface area, capture to collect some light shoot into lower sub reflector)



Projector lighting system waste a lot of light source. HID light source is so strong, doesn't have to use all of ray it comes from arc.

Blue circled part is contributing to above cut off slight illumination through window designed onto cut off shield.




Some projector uses texture surface finish selectively to the portion that contribute to output. That kind of texturing is to adjust local illumination intensity.

[NewShockerGuy]

Thank you for the information! I never knew that. I always thought that area (and the entire projector bowl) was used to focus the light. I see now that some of the things I worried about with the lines don't matter at all. I never knew that projectors wasted light.

-Nigel

[lowfat]

Can't believe I never saw this before. Very interesting.