Tag Archives: lighting

Lighting for Illumination and Indication

In our industries, lights play several important roles. Primarily, industries tend to use lights for two fundamental purposes—illumination and indication. Smart visual factories use lighting intelligently. They carefully differentiate between using it for illuminating devices and for indicating them.

Fixtures for illumination light up a space in the industry, improving productivity, worker ergonomics, and enhancing safety. For instance, in huge storerooms, low bay lights illuminate areas blocked by structures shielding ceiling or high bay lights. Another example is the use of task lights that offer bright and focused light required to perform finer tasks at workstations, such as inspection or assembly. Furthermore, operators can visually monitor machine processes and examine interiors of enclosures using heavy-duty machine lights.

On the other hand, the industrial use of indication devices provides visual status updates. For instance, an indicator light at a station lets a manager know he or she is needed there. A machine alerts an operator with an indicator light regarding material refilling or a jam. Indication devices often use stack or tower lights, with each segment indicating a different status when it lights up. A change of colors and/or a flash in domed indicator lights often indicates a change in status.

So far, industries had managed to keep the two categories distinct. However, with the advent of LED lights, manufacturers are trying to combine illumination with indication and merging them into a single flexible device. For instance, strip lights for illumination purposes so far, were using only white light. Now they use RGB LED lights that normally give off a white color, but they can also modify the lights to show different statuses by giving off multiple colors. The device therefore, is suitable for ambient or task lighting with white light, but can also indicate status with colored light.

Industries are now using multicolored LED strips in the sightline of operators to provide them with unambiguous status indication, while using the same in tower lights to offer the supervisors an indication at a glance.

By combining illumination with indication, machine builders not only enhance the visual appeal of their machine, and improve its functionality, but the sleek and colorful lights also offer tangible benefits to their customers. Advantages include faster response to status change promotion, improved ergonomics and limited waste movements, ensuring the addressing of critical status updates in a timely fashion, and reducing the risk of expensive accidents and mistakes.

The combination of illumination and indication devices is convenient for not only OEMs but their customers as well. As the combined devices fit easily into the framework of the machine, which protects them, they are effective in their function. Retrofitting an existing machine with a combined indication and illumination device is easy, as only a single device needs setting up, and fitting only a few wires achieves both the functions. The industry is using such combined devices in applications involving machine lighting, workstations, intersections shared by foot traffic and mobile equipment, automatic gates, overhead doors, and for collaborative robots.

The combined indication and illumination devices are providing both OEMs and end users with exciting new possibilities. Although started as a trend, the combined devices are proving their worth in industrial applications.

OLED Lighting in the Auto Industry

In recent years, a number of industries have started using Organic Light-Emitting Diodes (OLEDs) in diverse ways. The automotive industry, in particular, has seen a huge potential in OLEDs. For instance, very soon Audi will be coming up with OLED taillights. At present Audi has presented prototypes of the taillights. At the LOPEC Congress, Audi provides advanced insights into the needs of the automotive industry that the deployment of OLEDs will require to meet, and the future of automotive lighting.

So far, there have been plenty of developments. At LOPEC, Audi demonstrated prototypes of their OLED taillights, which they claim have reached production stage. However, using OLEDs in vehicles has always been a challenge, although OLED lighting installations and table lamps have been around for a while, and these are in use in museums, clubs, and restaurants.

Difficulties of Using OLED in Automobiles

Major hurdles OLEDs have to cross when in use in automobiles are they have to withstand humidity, heat, cold, UV radiation, and constant vibration. All these can reduce the life span of OLEDs drastically. Audi claims to have solved this problem by encapsulating their displays hermetically, which they claim will make the displays as stable as LEDs.

Why Use OLED in Place of LEDs?

Regular LEDs act as point sources of light, and it requires substantial development work for generating an even light from them. On the other hand, OLEDs are evenly radiating sources of light, and they naturally produce a uniform illumination. Moreover, their thickness is only about a millimeter, which makes OLEDs more suitable for automotive design.

Designers find OLED appearance is high quality, both when off and on. This is because it has a simple and clean surface. As design is an important aspect of the automotive industry, it makes OLEDs ideal for such use. Most automobile owners expect a certain lifestyle from their vehicles, apart from its functional use of transportation from point A to point B.

However, for use as turn signals and brake lights, the light intensity from OLEDs is not adequate, and will have to be increased. The automotive industry is also working on using flexible OLEDs. At present many are using glass-based OLEDs, but these are rigid, and using plastic foil substrates as the base for OLED is opening up a whole new world of opportunities for the designers.

Audi is expecting LOPEC will open up a huge bandwidth of business and research institutes for them. They expect to hold discussions with specialists using this breadth of activity, and to meet other OLED manufacturers and materials developers.

What the Future Holds?

In about a decade from now, the world will be witnessing innovations in vehicle lighting that most can only dream about today. As it is, a vehicle’s lighting system already functions as a form of communication—hazard lights, turn signals, brake lights, for example. In the future, driverless cars will need to interact with others on the road with even greater sophistication. One of the visions Audi has is of a three-dimensional OLED display extending the entire tail of the vehicle, on the panel of the body, and integrated OLED within the windshield.

Guiding Basics in Efficient Lighting Design

Discovery of fire and subsequently lighting has contributed hugely to the modern advancements in human life all over the world. However, only a few are aware of proper applications of lighting or that effective lighting also needs planning and design. Most people incorrectly infer lighting design to mean simply selecting lighting equipment for a system. Of course, selecting the most energy-efficient and cost-effective products is important, but they are simply the tools to achieve the design.

In reality, lighting design requires assessing and meeting the needs of the people who will use the space. It also requires skillful balancing between the functional aspects and the aesthetic impact of the lighting system.

That makes lighting both an art and a science. It also implies there cannot be any hard and fast rules for designing lighting systems. Additionally, there will also not be any single ideal solution optimum for all lighting problems. Typically, lighting designers face conflicting requirements and must set priorities before reaching a satisfactory compromise. Assets necessary for successful lighting designers include a proper understanding of basic lighting concepts, extensive experience, careful planning, assessment and analysis.

Lighting mostly involves use of energy. One of the chief concerns is achieving optimum energy efficiency, which means getting maximum lighting quality with minimum consumption of energy. This requires a combination of thoughtful design together with selecting the appropriate lamp, luminaire and control system. Additionally, decisions made must include informed choices of the level of illumination required, the integration and awareness of the space or environment being lit.

Lighting designers must have an intimate knowledge of the human eye and the way it perceives light and color. For example, light falling on an object is partly absorbed and partly reflected by the object. We see the object because of the reflected light entering our eye. The color of the reflected light also determines the perceived color of the object.

A flexible lens within the eye helps to focus the image on the retina and allows clear vision. The retina of the eye has many rods and cones. These convert light into electrical impulses that reach the brain via the optic nerve. The brain interprets the impulses into a proper image. However, illumination levels also change the way the eye perceives an object.

During the day and in normal daylight conditions, the cones in the retina enable us to see details in color. This is photopic or daytime adaption of the eye. As light levels dip, cones become less effective and the more sensitive rods take over. For example, in a well-lit street, the eye sees a mixture of cones and rods to see.

However, rods do not differentiate colors and respond only to different shades of black and white. The overall impression in average lighting is an image with lower color – the mesopic adaption. As light levels fall even further, such as in dim moonlight, the cones cease to function altogether and the eye loses all capability to see in color. This gives completely black and white vision – the scotopic or nighttime adaption.

Incandescent Bulbs May Not Be Dead Yet

If you thought that incandescent bulbs were dead and buried, well, you need to think again. Although incandescent bulbs had many things going in their favor such as a warm glow, dimming capability and low cost, efficiency was not one of them. Most of the energy that went into an incandescent bulb was wasted as heat and only a little was converted into visible light. Now, scientists at MIT and Purdue University are developing an ultra-efficient new incandescent light bulb. It reuses the heat it gives off by converting the heat into light.

Traditional incandescent bulbs heat a tungsten filament, causing it to glow. This also creates both visible and infrared light. While the visible light is useful, the infrared wavelength is dissipated as heat and is hardly of use. In the new type of incandescent bulb, scientists have coated the filament with a structure called photonic crystals.

Photonic crystals are made from abundant elements and applied on the filament using conventional material deposition technology. Although the crystals allow visible light to pass thorough unimpeded, they reflect the infrared wavelengths back into the filament. This heats the filament further, keeps it glowing and emitting more of the visible light, while the bulb itself uses much less electricity than it does otherwise.

According to the scientists, the bulb can have a high luminous efficacy, a measure of how well a light source produces visible light – a ratio of luminous flux to consumed power. For instance, regular incandescent bulbs show a luminous efficacy of 2-3 percent, CFLs come in at 7-15 percent (excluding ballast loss) and LEDs at 5-20 percent. The new, two-stage incandescent, once developed further, would be able to manage greater than 40 percent luminous efficacy.

For those who perceive luminous efficiency in lumens per watt, the maximum luminous efficiency of 100 percent, is 683 lm/W. That means, incandescent bulbs have a luminous efficiency of 13-20 lm/W, CFLs of 47-103 lm/W and LEDs are 34-136 lm/W. Comparatively, it is expected the new incandescent bulb would show a luminous efficiency of 273 lm/W.

To make the concept successful, scientists had to design the photonic crystal such that it worked for a very wide range of wavelengths and angles. They had to make the photonic crystals in the form of a stack of thin layers, which they deposited on a substrate. The efficient tuning of how the material interacts with light depends on the right thickness and sequence of the layers, according to the scientists.

The photonic crystals cover the filament, allowing only visible light to pass through. The crystals reflect infrared light just as a mirror would, adding more heat to the filament. As only the visible light goes out, the heat waves keep bouncing back into the filament until they can come out in the form of visible light.

Although at present the luminous efficacy reached is only about 6.6 percent, it is rivaling that of the commercial LEDs and CFLs. However, it is too early to say the two-stage incandescent will be able to beat the LEDs, because research on LEDs is also progressing very fast.