When the direction of the incoming beam is changed the interference pattern also changes direction, hence a shift results on the screen. An uncollimated beam is an incoherent superposition of beams from different directions. The results is a convolution of shifted interference patterns, in other words the image will be blurred.

The main reason a collimated beam is usually used to illuminate a grating is not that it's necessary; it is simply that it's simpler to visualize what's going on.

The production lines have automated processes for electrode processing and emitter dosing. Vision systems check the positioning of the electrode. All lamps are checked at the end of the line and if they do not fulfil the requirements, these are automatically rejected. As a result, we can guarantee a constant quality of our lamps.

In all of the images I've seen from a spectrometer, there's always a collimating element that places an image at infinity so as to have parallel rays hitting a diffraction grating. But why do we need that? I understand that the theory behind gratings is based on a plane wave hitting the grating, but if that were not the case, what implications would it have? I ask this because collimating a beam of light doesn't seem to be an easy task specially if the light source is something like an LED or a simple incandescent bulb, but that's another question, I suppose.

If the beam wasn't collimated then light with different wavelengths but from different parts of the source, arriving at different incidence angles, would be diffracted in the same direction.

UV radiation can be used for multiple purposes in water, air and surface treatment, but is primarily employed as a disinfection process that inactivates micro-organisms without chemicals.

I completely disagree with the answer by @ProfRob. If a beam is focused beyong the grating, it forms the focused image of a spectrum at the distance of the undiffracted focused beam. As long as the incoming beam has high spatial coherence, the wavelengths are well separated at that spectrum image. Of course aberrations can occur.

Philips has always taken the lead in reducing the amount of mercury required to operate fluorescent lamps. To dose the mercury in the lamp we use a unique mercury capsule that results in:

Philips UV-C lamps disinfect surfaces and objects in a wide variety of settings. These include hospitals, schools, offices, factories, retail outlets and the food and beverage industry, as well as modes of transport like aircraft, buses and trains. Philips UV-C lamps can also be used to disinfect air in a room and keep HVAC systems clean. They work in upper air systems that disinfect passing air, open UV-C systems or robots that disinfect rooms and locations overnight or while rooms are not being used, as well as in air conditioning systems. For water purification, Philips UV-C lamps can be applied in drinking and waste water treatment in residential, industrial and municipal applications. They can also be used to disinfect water in swimming pools, jacuzzies and fish ponds.

Ultra-Violet (UV) light is invisible to human eyes. It can be subdivided into three categories: UV-A, UV-B and UV-C. UV-A from 315 to 400 nm UV-B from 280 to 315 nm UV-C from 100 to 280 nm.

Bacteria and viruses that cause common infections can live in water and air, as well as on surfaces - even after normal cleaning. Disinfection systems incorporating UV-C lamps have the power to neutralize these harmful micro-organisms.

All Philips UV-C low pressure mercury lamps contain a unique coating on the inner glass wall that ensures the UV-C output over the useful life of the lamp never drops below 85% of its initial output.

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