Solid State Flashlight with electronically Controllable Beam

Concept: Solid State Flashlight with electronically Controllable Beam.

Date: 24/03/2006

Background: Ever since I got a Mini Mag 2AA Light with a Focusable feature, I had always dreamt of something similar without the mechanical aspect. The mechanism is clumsy and makes an ugly donut hole when we require a wide beam. Also the beam quality is very poor. To conquer this, some manufacturers have spluttered the reflector. This has although increased the beam quality to some extent the fragile Focusing mechanism still remains. With the advent of new Light Emitting Diode technologies, the problem of fragile filament bulb has also been solved. Today we see more and more bright LED Lights, with spluttered reflectors and same old mechanical focusing.

I attempt to address the mechanical focusing problem with a simple but yet radical innovative concept. Imagine a light with total solid-state devices and no mechanical components at the business end of the flashlight. A flashlight with no moving parts yet gives you full control on the quality of beam including adjustable focus.

Definitions:

• Emitter: A solid-state source of light.
• Intensity: The intensity of light at its point of origin affects how brightly the light illuminates an object. A dim light cast on a brightly colored object shows only dim colors. Intensity at any given point is expressed in Lux / Candelas (unit of light).
• Attenuation: Light diminishes over distance. Objects far from the light source appear darker; objects near the source appear brighter. This effect is known as attenuation.
• Beam: in a flashlight, the rays of light directed by a combination of Parabolic Reflector and a light emitter forms a cone of light.
• Beam Angle: The angle that is formed by the rays of light in the beam from the source of light. Beam angle is expressed in degrees.
• Hotspot: Intense circle of high intensity light produced by the beam of light.
• Falloff: the light rays surrounding the hotspot as a result of source of light not being a point.

Following figure should explain this clearly.

The Concept: So far, the only way to control the beam of flashlight was the mechanical way i.e. by moving the reflector away or near to the emitter of light that is placed near the focal point of parabola. Adjusting the location of reflector would cause light being out of focus and cause the beam to widen. However, in this concept, instead of adjusting location of reflector, I intend to modify the light that is emitted.

Emitter Type 1:
Consider the following image.

As you have noticed, there are circular rings emitting light of varying intensity. Controlling intensity of each ring, we can alter the beam angle, hotspot and falloff giving you complete control over the beam quality.

We may need technological advancements to make this concept possible. I believe that with current technology, we can create such a light source. Using the multi layer microprocessor chip technology to 'print' the concentric circles of light emitting material over the controller chip.

Emitter Type 2:
With the color of beam also being a concern, we could use a RGB Matrix of nano dots to emit light in concentric circles with desired light color (including white light). The nano RGB dots with today's technology could be of the size of 90 x 90 nm (Nano Meters). However with enhancements of technology in future the size of dots could be as low as 1 nm giving more fine control and resolution of the light.

The Type 2 emitter light can also be used as a source of projector flashlight (a flashlight that can project images / video) with use of a Lens Attachment.


Emitter Type 3:
An inverted cone emitter with type 2 features. The shape of emitter will give better control and a wider beam angles. This emitter currently is not possible to build however with advancement of nano technology building, it would be possible to build such an emitter.


Emitter Electronics:
The emitter is a self-contained multiplayer microprocessor with top layer of light emitting material. The layer just below the light layer would be controlling the intensities of individual nano dots / rings. The emitter control circuit communicates with peripheral intelligent components through a 'light bus' of 32 or 64 bit width. On-chip peripheral components will include a blue-tooth controller and wireless IEEE 802.11 a/b/g controller to talk wirelessly to for external wireless control of the emitter. Since the emitter will be self-contained with control circuit, only external components will be power supply, wireless antenna and interface components.

I have skipped all the internal details and above is presented only as a concept for general understanding here.

It's just a concept... open for free discussions.... and hope anyone would not 'steal' this concept making way to any patent... we already have got enough from MAG LED...

let this be a free and fair idea...let's discuss and let it evolve in to a new product family / class.. rather than just in books or topic for some book / records.

Many possibilities

Well, just off the top of my head:

MEMS --Micromirror arrays

A micromirror array chip could be used in such a device to shape or reflect the beam in any way without have any 'large' moving parts... Although it kind of DOES move...

LCD -- Liquid Crystal lens:
Why not have a lens with a liquid crystal plate inside that can selectively block sections of the light, in a user definable pattern.

(similar to how some projectors work)

You could also have multiple emiters and Optics as well. (1 shortrange prefocused LED + Optics, 1 Long-range Prefocused optic + LED, and a few LEDs around the outside of the lens assembly for general mid-range/non-directional lighting.)

You should not need any (more) nanotech than what is already available.

I wonder if polarized correctly a LCD could act like a mirror. (?) That might be very useful for such a light.

Re: Many possibilities

Viren - very interesting concepts. Some issues I feel you may encounter however (keep in mind I have limited knowledge on lighting, LEDs, etc...just my ignorant thoughts)...

- I'm not very familiar with LED processing, but there may be limitations on size reduction of the device, including deposition capability of phosphors.
- A multilayer microprocessor chip is still only a single layer of silicon. Various areas/wells are deposited/implanted into the base Si to achieve various P-N junctions for form different devices, but most of the "layering" is actually metal layers on top of the silicon to individually control the various P-N junctions and provide communication between junctions (actual devices, be it bipolar, MOS, etc.) across the chip's area. After this metal layer is placed on, Si can't be added again. The only thing I can think of is if a method similar to SOI (Si On Insulator) is used, but then, conductive control paths would be required within the insulator to allow the u-processor beneath to control the top layer of Si. You can possibly do a hybrid circuit, but doing one on a micro-scale would be difficult also while keeping overall package size down.
- LCD - liquid crystals would be good to use to block and unblock emitted light as Melchior suggested. However, if light is blocked to change the output beam pattern, you get a reduction in light output also, which would be an unwanted result/side-effect. Also, liquid crystals require filters (mechanical, oriented at 90degs) to block and unblock light.
- Last issue, cost of making this happen. The smallest technology is there, but for processing, but LEDs. Again, don't know the constraints on LED processing. Cost to transfer that technology to LED may be quite high. Even if that can be done, the research required to develop a u-processor + LED tiered chip or micro-hybrid circuit would be very high. Most displays and other applications of LEDs don't require a specific focusing of the beam pattern (i.e. backlight of newer LCD displays). The flashlight market (seemingly the only market that really cares that much about the focused beam pattern of light) would be too small for companies to justify the research required to make this happen. The only way I see funding coming for this would be if the government decided to no longer use the existing lighting technology and go for LEDs. The halographic imaging does sound interesting tho and that may likely be the best driver for this idea.

Cool stuff!

Re: Many possibilities

Interesting idea. Far away from what we have today, but could work. Lots of electronic control would be needed for sure!

Re: Many possibilities

Widen the beam by increasing the reflector/optic "error," eh? Interesting concept.

It should be possible to make a flat, concentric emitter with existing technology. Just use really small die and some excellent heatsinking tech ala Lamina. It would take some effort to pack in the die close enough for this concept to work fairly well...

I don't think the electronics would need to be terribly sophistocated either. Widening the "beam angle" would be a matter of switching on outer rings of LEDs and increasing current to them - likely decreasing current to the center LEDs to keep power consumption even & manage heat.

A potential application for this concept some way down the road would be automotive headlights, assuming that LED efficiency and power increases to the point that you can use a single "point source" emitter as opposed to arrays. With a well-designed reflector, you could possibly manage both low/high beams and "steer" the beam for turning corners.

Maybe you could just change the shape of the reflector using piezo actuators and make the beam any shape/size that you want. It wouldn't technically be solid state though...

Nice idea, but flawed. From what I understand you merely wish to 'shape' the beam by controlling any beam overspill at the sides.

This is quite different from what a mechanical focusing mechanism does (e.g. as fitted to a Maglight), as all available light will not be focused into a narrower/brighter beam. Instead it simply attempts to reduce the side spill by switching off/dimming the outer concentric rings/emitters resulting in less light output as the beam is narrowed.

Secondly, light emitted from a flat surface will disperse at all angles unless focused into a beam via a mirror and lens.

It might be possible to control/focus the beam by phase-shifting the light emitted from the concentric rings (some advanced airbourne radar systems work similar to this), but again, this will result in available light being wasted due to beam shaping (constructive/destructive interference). It would also prove extremely complex and expensive to do, and would have little practical benefit.

Essentially, this idea is a non-starter. Interesting train of thought though...and brave of you to post it here. Sorry to rain on your parade.

The concept can be employed in an array of LEDs. For example, the inner section can contain 18, 10 degree beam width T-5mm while the outer group of 18 has 45 degree beam width leds. Not as eligant as morphing the beam from one focus to the other, but it works.

It may also be worth investigating if it is possible to have a reflective flexible diaphram with a electro-magnetic coil on it, so a control voltage would change the shape of the reflector, just like a speaker.

Instead of changing the focal length of the reflector, change the focal length of the lens.

A lambertian Luxeon emitter has a dome (lens) of clear epoxy over the LED. The fixed refractive characteristics of this lens dictates the dispersement of light against the reflector. Why not lose the dome and fit a small precise articulated lens over the emitter instead?

1. Use a piezomechanical device to change the focal length of a crystal lens
2 Use a piezomechanical device to "stretch" a flexible lens concentrically like
your eyes do. Either can be controlled with a minute amount of current and would require only simple electronics.

Bernie
Inventor

I thank everyone for the wonderful responses.

Please note that anything mechanical is more prone to failure as compared with solid-state things. Use of piezo mechanical devices, liquid crystal devices and lenses is all are susceptible for failures, although they will definitely be more stable than current R & P mechanism that MAG is using.

The Type 2 Emitter is similar to OLED Array; there we already have the technology, except for the emitter's brightness and resolution. In simple words, OLED's will be 'printed' over the chip as against current glass / plastic substrates.

The control chip wont be all that complicated, definitely not as complicated as a computer's chip but I would compare the complexity to video processor of high resolution and additional peripheral devices controller.

True, it will require a lot of resources and money to develop. But once developed, it will be a great thing and as many of you have pointed out, it will have many applications like car headlamps etc. in fact every area where light is required and we need to have control over the beam.

Wow!

Along the general lines of solid state beam shapers, doesn't the camera in some cell phone have a focusable lens made of water and manipulated by some kind of field of sonic waves?

There's one company out there with a working "one moving part" varifocal lens (Vari-optic, I think) that consists of 2 fluids in a chamber with different indices of refraction; apply different voltages to the chamber walls and the miniscus between them changes shape.

I want to say that Philips has a similar project and is embroiled in a patent dispute with the original company. The Philips design uses much lower voltages. Both are very fast, low power consumption and retain their position if power is removed. The maximum aperature is fairly limited with both designs...

There's another company that makes a simple varifocal lense with fluid and a tiny hydraulic ram; vary the position of the ram and you displace fluid from the miniscus/cylinder.

Neither is quite "solid state," but the number of moving parts is minimal.

I know very little about all this technical stuff so I'm probably way off. But wouldn't this system, rather than focus the same amount of light into either a flood or spot, simply reduce the amount of light to achieve a spot. And wouldn't this defeat the purpose, because when you focus a light you want it to throw further not just emit a different shape of light?

Wow! Sure would want to see one of these when it comes to light!

jonman007 said:

I know very little about all this technical stuff so I'm probably way off. But wouldn't this system, rather than focus the same amount of light into either a flood or spot, simply reduce the amount of light to achieve a spot. And wouldn't this defeat the purpose, because when you focus a light you want it to throw further not just emit a different shape of light?

Click to expand...

Short answer:
No

Long answer:
The "flood" mode could potentially spit out more light than "spot" since the geometry dictates that the wider the "flood," the more individual light elements have to be switched on.

Nic said:

Secondly, light emitted from a flat surface will disperse at all angles unless focused into a beam via a mirror and lens.

Click to expand...

...and that's why Luxeons look so terrible in a Mag reflector

The nature of a flat emitting surface is why this idea has some validity - if you introduce a uniform "error," you'll increase flood as you activate rings further away from the center. I don't doubt that output might be a bit "ringy," but likely better than the "ringiness" of a typical defocused incan. The tighter you can pack the individual light sources, the better.

This concept would allow for simultaneous spot & flood.

idlleprocess has got the idea right

In the type 1 emitter more the rings (higher resolution), more will be the control over the beam and the patern. In an absolute flood mode, Whole of emitter rings will glow to produce simultaneous flood and spot. for even flood, the inner rings have to be dimmer than the outer rings to produce even flood.

the beam patern will definately be better than the M@G lights

What's so unreliable about mechanical? Optical zoom on cameras, as well as the electrochemically operated mechanical focusing mechanism in our eyes seem pretty reliable. Those DLP mirror systems with their millions of moving parts and spinning color wheels seem more reliable already than say, overdriven LEDs. Always good to focus on the most likely points of failure first (because those will determine the useful lifetime of the product), and for me it has always been the Mag switch, not the focusing mechanism.

Yes the focus problems would seem to derive from the relatively large size of the LED die, so perhaps if the phosphor bed was mounted on a deformable membrane, focusing could be accomplished by changing the shape of the LED itself.

bgf9000, it's not just the mechanical thing, but the beam quality too. It's true, that zoom cameras etc have a great mechanism. but i want to eliminate the mechanical thing all together. electronic control would be a great thing as compared to utilizing electromechanical focusing mechanism.

Fenix lights have fixed focus and it works perfectly. Only reason incandescent lights need a focusing mechanism is to cope with different bulbs having their filaments located at difference locations relative to the reflector. The flood/spot capability is simply an added benefit, but usually flood leaves an ugly donut in your beam. Good luck...

Nic, Please read #1

this should clear a lot of doubts if any.