Directional Lighting with Fiber Optics is Better than with LEDs

by Michael Groves

When designing lighting for prototypical scenes (i.e. ones that reflect real life), especially those of a bygone era, the style of lighting is very important.  One of the features of street lighting through the first two thirds of the 20th century was directional lighting.  In other words, the light shone directly down onto the path or road or subject without a huge flare to it.  It created a spot.  Below is a picture of what is meant.

This picture is from an N scale layout of Paul McCarty who is using the Dwarvin N Scale Swan Neck lamps.  Notice the man reading the newspaper under the street light, but that the surrounding areas are not well lit.  This is a typical example of directional street lighting.

When choosing the type of lighting on your layout it is therefore critical to ask the question, what sort of light am I after.  Do I want directional or flared lighting?  Fiber Optics can provide either.  In its native form, it is naturally directional, which can be seen from the images in this article.  If you desire a more flared approach, create a convex lens at the end of the fiber which can be easily achieved by heating the fiber briefly.  The fiber is a PMMA plastic and has a melting point of 160oC, so be careful when heating it. 

Another example where directional lighting is required is for building lamps that are found above doors in the industrial parts of a town.  It’s important to only light the area close to the doo and not a whole area.  This reflects the use of Dwarvin's Industrial Building Lamps, which are currently in HO scale.

Directional LED Lighting beam spread challenge:

Let’s take a look at the state of the art with LED lighting.  Ever since the advent of grain of wheat bulbs and then LED’s, model lighting has been dominated by lighting that casts a wide angle of light.   Indeed, typical viewing angles for small LED’s is around 60o.  This means that the beam spreads out at 60from a line perpendicular to the LED, in other words, it has a spread of 120o.  To see what this means, see the image below:

One can buy specially narrow beam LED’s but these are not readily available to the hobbyist.

Fiber Optic Directional Lighting:

If on the other hand one looks at the typical beam coming from a fiber optic light, the total spread is more like 40o, as can be seen by comparing the N scale Swan Neck lamp image and an overlay image below of a 40o beam spread.  This reveals a 40spread. which equates to a 20viewing angle.

The reason for this feature of fiber optic lighting is that light travels through a fiber, bouncing off the walls, but only within a critical range of angles.  Hence, the light at the end of the fiber fills a relatively small viewing angle.  When it emits from the fiber into air, the beam spreads considerably as a result of the difference in refractive index of the liber (1.5) to air (1.0).  As noted in another article, this difference in refractive index will cause the light to bend as it emits from the fiber.


Why does the directional lighting topic even warrant some space?  

I have been approached by quite a few customers who have informed me of how much better fiber optic lighting is because it is so much more prototypical being more directional.  Hence, I thought it would be helpful to write up something of this benefit and provide some degree of quantification around it.  

My main focus has been and still is, to provide the simplest lighting solution possible to modelers and myself, which is why I developed the system.  The directionality feature, I must say, is an act of serendipity.  (Serendipity is defined as the act of finding something valuable or delightful when you are not looking for it).  The attractiveness of this feature is something I have had to learn from my customers - a big thank you to you all. 

The road repair image below reveals how fiber optic lighting provides these guys with  great lighting, without flooding the surrounding area.

How about this image which reveals how a small industrial building lamp really helps a small area to pop out to focus on the purpose for a garage on your layout?

Have fun with your lighting!

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