2014年5月30日星期五

LED street lighting/Alumbrado carreteras/Alumbrado Vial/LED straatlamp


Photos of old lighting, left, with new LED street lights on the right.
While there are many benefits to LED streetlights, there are some downsides too. They only provide directional light, so they can't produce a spherical "glow" emanating in all directions, like most lights. Because of this feature, they are generally used in streetlights that are hanging or facing downward, rather than in lamp-type lights. Still, they are considered well-suited to outdoor applications and some people have appreciated the directional light, as it doesn't cause streetlights to shine into homes or create light pollution by shining light into the sky where it's not needed.
The initial cost of LED lighting is high, and consequently, it can take several years for the cost difference to be made up through cheaper energy bills. An LED streetlight costs around $1,000, while standard lights cost $250 each. Similarly, a 60-watt fluorescent bulb for a home lamp can be purchased for $1, with a similar compact fluorescent bulb costing around $2. But an LED bulb, produced by Phillips and designed for home use, costs $107. The high cost derives in part from the material used: LEDs are often made on sapphire or other expensive substances.
Some users have been disappointed in the brightness of LEDs. But new technological developments have LEDs closer to producing classic bright white light. Eventually, LEDs are expected to be able to produce all colors of the spectrum, but for now, they are generally limited to red, yellow, green (hence their use in traffic lights), blue and a white that bears a slight blue tint [source: Britt].
While cities are trying to think long-term and, in the United States, seeking stimulus money to help fund LED streetlight conversions, the cost may be prohibitive for some municipalities. In light of the recession, some cities are turning off existing streetlights to save on electrical bills. Others are looking into adding motion sensors that activate streetlights only when pedestrians are detected.
Finally, some experts think that though many cities are interested in LED streetlights, the greatest barrier to widespread adoption of the technology may simply be education [source: McClear]. Many people are unaware of the many uses of solid-state lighting, as LEDs are classified, and that high initial costs can lead to long-term savings. But with companies like Phillips investing millions in research and development and clamoring for valuable municipal contracts, LED streetlightscertainly have a bright future.
Amidst all the hubbub about tackling global warming and cultivating green energy, one subject receives little coverage: streetlights. While an important public service, streetlights are expensive to maintain and taken together, suck down a lot of energy. So when a city like Los Angeles announces that it's converting 140,000 streetlights to light emitting diodes or LEDs, and Pittsburgh states that it's considering doing the same with 40,000 lights, it's time to take notice.
LEDs are gaining traction as a great alternative to traditional lighting because they are relatively environmentally friendly, don't consume much electricity and have long life spans. They last so long -- 14 years or more in some cases -- that they can be considered "semi-permanent" [source: Rosenthal and Barringer].
Some of the world's biggest electronics firms are now touting LEDs as the next big thing in lighting, whether in a small appliance or the biggest skyscrapers. By 2013, the LED market, which covers anything from holiday lights to those on the Empire State Building, is expected to be worth $1 billion [source: Rosenthal and Barringer].
In the past, LED lights had been seen in devices like indicator lights in appliances, calculators or in large sports scoreboards. But now, many large cities around the world -- Los Angeles, San Francisco, Toronto and Tianjin, China, to name a few -- are now switching to LED streetlights. Portugal is in the midst of a massive conversion program that is expected to encompass all of its streetlights.

2014年5月13日星期二

CFL vs LED


The analysis shows that CFLs and LEDs have pretty much the same running cost per year. However, there are many reasons why LED bulbs are much better than CFL, so are perhaps worth the extra cost.
  • Since they consume half the energy, they put less of a drain on the electricity grid. In India we have a tremendous shortage of electricity so whatever one can do to reduce consumption is good.
  • Nowadays, many people in Bangalore have an inverter. Typically, one can run 4 or 5 incandescent bulbs for a couple of hours. With the same inverter, one can run LED lights for the lights will run for much longer on it - in this case, around 20 hours!
  • CFL bulbs are not very environmentally friendly - they contain mercury and have to be disposed off carefully. They are quite delicate and break easily. They are supposed to last three years or so but quite often do not last so long. LED lights are supposed to last 20 years without substantial degradation, so the environmental impact is much less.
  • Over time CFLs degrade substantially. Often, one of the filaments burns out and this results in a reduction of intensity of light.
  • Another issue with CFLs is the quality of light. It does not have all the frequencies that the light from an incandescent bulb has - so some things look different. This might be a problem with LEDs as well but is more easily addressed.
  • CFL bulbs can not be dimmed so you cannot regulate the light very well.
  • LED lights, on the other hand, are very versatile. Pretty much anything is possible with LEDs. Since the bulbs themselves are very small, they can be made in all kinds of shapes and colours. There now exist LEDs whose colour can be varied and adjusted by a smartphone app. So one can have different colours of lights for different times or moods. You can also program them to turn on or off at certain times of the day.
Light can promote peace!
One cannot underestimate the importance of light. Apart from the obvious practical benefits of being able to function in the dark light has tremendous influence on our psychological state. High intensity light exposure is the treatment for people who suffer from Seasonal Affect Disorder - depression caused by lack of exposure to sunlight. Jet Lag can be treated by regulating light exposure.
So the lights you put in your house can have a significant influence on your life. In fact, in Los Angeles, some Sodium vapour streetlights were replaced by LED lights. Apart from a tremendous reduction in maintenance costs and energy savings an unexpected side benefit was a significant drop in crime in that area!
While I am advocating running out and replacing all your incandescent bulbs with LED bulbs I am not quite suggesting running out and replacing all your CFL bulbs with LEDs since that would not be environmentally friendly. However, every time a bulb goes bust in your house, I recommend that you replace it with an LED equivalent. You will save yourself a lot of money in the long run and do your bit for saving the planet.
The cost of an LED bulb may seem to be high - but as the analysis shows, it is still a better deal in the long run. However, there is even better news. The cost-per-lumen of LED bulbs is supposed to follow Haitz's Law, which asserts that the cost per lumen will drop by a factor of 10 in a decade. So if you wait a bit, unlike most other things, the price will come down! And, like in the case of computers, you will get a better product.
So, go LED, as soon as possible!

2014年5月12日星期一

Light for different room

Lighting is one of the key elements that helps make your house a home. The proper lighting enables you to perform tasks easily, makes you feel safer and more comfortable, and allows you to enjoy your home at its full potential. Each room, however, has specific and unique general and accent lighting needs. Here are some tips and ideas to consider when planning your lighting needs for each room in your home. If you are uncertain about what type of lighting fixture you need, or you're just looking for inspiration, take a few minutes to browse through this guide!
Foyer, Halls, and Stairways
Use lighting and decoration for a first impression. The foyer conveys the first impression of a home's interior. Center a traditional chandelier, contemporary pendant, or transitional close-to-ceiling fixture in your hallway to provide basic illumination and create a welcoming atmosphere.
  • Make your artwork come to life and illuminate it with halogen light from track or adjustable recessed down-lighting. Mirrors also add a special decorative touch to a foyer.
Make sure to size the decorative fixture to the space. Not all foyers can accommodate a large chandelier, so make sure the size proportions are correct. Likewise, if you have a larger space, you'll need a larger fixture. If you'll be able to view the fixture from above, make sure to select a foyer chandelier or pendant that looks attractive from second story viewing.

Remember that stairways and halls must have good general lighting for safety.
 To prevent accidents, stairs should be lit from top to bottom with switches in both places. For safety in hallways, place lighting fixtures every 8 to 10 feet. Tie in the fixtures you choose by matching your foyer chandelier or pendant with close-to-ceiling fixtures for hallways and smaller chain hung fixtures for stairways.

Use matching wall sconces to complement the hanging foyer fixture.
 Always mount a sconce above eye level (approximately 66" from the center of the fixture to the floor) so that the lamp source is not visible.
 Living Area
Use lighting to bring out the best in your living spaces. Enhance your room's ambiance, dramatize wall textures, accent artwork, or just provide general illumination for your den, living room, family room, playrooms, or bedrooms. A variety of different types of lighting fixtures will work for both your general lighting and accent lighting needs.

Use recessed lighting to light a general area.
 This is preferred because the light source is concealed. Close-to-ceiling fixtures, wall sconces, and interior lamps are also excellent choices and provide ample lighting. These fixtures are not only decorative pieces, but are ideal sources of task lighting for reading or playing games.
  • While traditional wall fixtures with arms remain the most popular form of wall lighting, more contemporary wall sconces are gaining popularity for accent lighting.

Try recessed lighting or track lighting to make a room come alive by accenting artwork, wall washing, or grazing.
 Interior lamps are also a great choice.
  • When table space is limited, wall lamps are a good alternative.
Try LED Lighting to get more value for your money.

Dining Room
Create a focal point with lighting. Your dining table is in place, chairs are pushed in, and the table is set. The only thing remaining to complete the picture is the center piece, your light fixture. This lighting fixture is the focal point of your room, so it needs to express your own personal style, while still satisfying general lighting needs. Whether your dining and entertaining style is casual and laid back, or is generally more formal, choose a fixture that reflects you.
Use a chandelier or pendant for general lighting. Both fixtures are excellent sources of lighting and are sure to set the tone of your dining room. Recessed wall washers can also provide additional light while helping to create an illusion of a larger room space.
  • When hanging a chandelier, make sure that the chandelier is 6" to 12" smaller than the narrowest side of the table. The bottom of the pendant or chandelier should be approximately 30" above your table.
  • Chandeliers with 200 to 400 overall wattage provide abundant illumination for a dining room.
  • Consider a chandelier with an integral downlight for additional light on the table.

Add accent lighting to the room, too.
 Aim adjustable halogen recessed fixtures on the table and chandelier. This will provide additional light on the table, and will also bring out the brilliance of the chandelier. Consider companion sconces on either side of a china cabinet or hutch. Cabinet lighting mounted inside valences and cabinets also adds drama.
Kitchen
Realize that the kitchen is often the busiest part of the house. Not only are your meals prepared here, but your family and guests gather here as well. Sufficient and adequate lighting is a must for performing all your culinary needs, helping your kids with their homework, and reading the paper.
  • Sketch a plan of your kitchen that focuses on activity areas and then decide what kind of light each area will need: general, task, accent, or decorative.
  • Use higher watt bulbs in task areas.
  • A glass or plastic pendant will provide ample "up-lighting" to cover the entire dinette area with light.

Go with decorative fluorescent fixtures centered over a workspace.
 Kitchens less than 100 square feet require a two lamp fluorescent, up to 250 square feet will require supplemental lighting. Down lights mounted 18" off the edge of the cabinets, and spaced 3' to 4' on centers is an excellent way to create additional general lighting.
Use undercabinet lighting to help prevent shadows on the counters, while adding critical light to the workspace. Fluorescent undercabinet fixtures are also a cost efficient lighting source. In open areas over sinks use recessed downlights mounted directly over the sink.
  • Mounting mini-pendants 18" to 24" above the work surface is an ideal way to light up a breakfast bar or counter dinettes, a pendant on a dimmer, hanging 24" to 30" above the table, is ideal for task lighting. Size the fixture to roughly 12" less than the diameter of the table.
Illuminate your special home objects, architectural detail, or food presentation areas with track or recessed lighting. Use under cabinet lighting in cabinets, valences, and toe spaces and create drama while also supplying additional light to navigate around your kitchen in the evening.
Choose fluorescent lights to provide that missing ambient lighting. The ambient light provided by fluorescent fixtures will fill in your kitchen's shadows, reduce contrast, and light vertical surfaces to give the space a brighter feel.
Bath and Vanity
Don't forget about the bathroom. Bathroom lighting is probably the last place people want to invest time and money. Mirrors go unlit, and oftentimes one ceiling fixture is used to light up the sink, mirror, and shower. However, as whirlpool tubs become larger and steam showers are added, more and more time is spent relaxing in the bathroom. Since you begin and end your day in the bathroom, why not spend a little extra time considering which fixtures and lights would work best?
  • Halogen bulbs are generally the standard for bathroom lighting, but the newest compact fluorescent bulbs are also a great option.
Use several recessed down lights or decorative surface-mounted fixtures for areas over 100 square feet. Add companion close-to-ceiling fixtures to supplement bath wall brackets in larger bathrooms. Companion close to ceiling fixtures supplement bath wall brackets in larger bathrooms.
Mount one fixture over the mirror to light a bathroom, but realize it can cause shadows on the face. If using recessed lighting, avoid creating shadows by not mounting them directly over the mirror.
  • Adding wall brackets to the side of the mirror is one of the best way to eliminate shadows on the face. For mirrors under 48" wide use, vertically mounted wall brackets and position them 75 to 80 inches above the floor.
  • If the fixture uses exposed lamps, do not use a higher wattage than 40 watts. Fixtures with clear or well diffused glass use nor more than 75 watts. Color corrected fluorescent lamps should be used when fluorescent fixtures are desired. A crisp white light renders skin tones most accurately.

Use extra lighting in unexpected areas for both decoration and function.
 Try a small recessed light directed at a piece of decorative art work or a beautiful powder basin creates an extra layer of lighting.
  • In the shower, use recessed lights or a ceiling mounted plastic unit. Angle a recessed shower fixture and highlight nice tile work or make your shower fixtures sparkle.
  • Don't forget the area over the commode! A recessed unit is always a great addition.
Exterior Lighting

Use functional and fun lighting outside.
 Whether your goal is to enhance the beauty of your home, or provide additional security, you have numerous lighting options to light up your home's exterior. Extend the hours you can spend outside, or create a festive environment!
Consider the types of lighting available. The selection of lighting fixtures is of two primary types: decorative and functional.
Use decorative fixtures are used along pathways, on walls and posts, and entrance foyers. The design of these fixtures should complement the look and feel of your house and landscape while providing sufficient lighting for safety, security, and functionality.
  • When installing a wall lantern, size the fixture to the door and surrounding space. Wall lanterns should be mounted slightly above eye level at about 60" to 66" from the center of the fixture to the floor. Post-top lanterns can be selected to match the style of the wall lanterns. Large post top lanterns make a better impression when used in large open space.
Be mindful, however, that most lantern-style fixtures are glaring light sources.They spill light in all directions and can be a cause of light trespass (onto others' properties) and distracting glare for drivers. Many lighting designers forgo lantern style lights entirely and instead use lights with hoods (that shield the glare) and lights that are positioned within plant material so they are hidden completely.
Use hidden lights for functional purposes. They are strategically positioned around the property to selectively illuminate plant material and architecture. A skilled lighting designer positions fixtures so only the effect of the illumination is seen, not the lighting fixtures themselves.

2014年5月9日星期五

LED Lighting Design


Lighting design is not only an art, but also a science. Art requires beauty and science requires truth,which led to the lighting design should combine light relative degree ,color temperature, light major or minor, and melodic beauty with illumination, electrical, controls and energy saving.Without professional design, it is easy to go astray. 
Shopping centers ,which is a key battleground of LED lighting designare usually located in the city's bustling business district. But that does not means the brighter the better, it depends on many reasons strictlyHow could the shopping mall being outstanding among the many buildings when is becomes dark ? And what kind of lighting design Design will attract customers? How could the designer create fascinating, unique outdoor shopping Plaza building lighting? Commercial building architectural have many features especially in the functional diversity, integration,and good location , relatively large volume ,transport stream complex,and diverse. Therefore, shopping mall as a standard commercial building, its appearance is more focused on commercial lighting design.In addition to landscaping and lighting based on the structural characteristics of the building itself outside , methods and means of illumination can be varied , the appropriate use of dynamic lighting and color light warm atmosphere will be more prominent .
The performance  in the night is freewhich pursuits of colorful , dazzling , reflecting the prosperity of the scene. To create a strong business climate ,the way of expression shall be diversity and freedom , but also a strong irritant.
In addition, many aspects of lighting design should be considered.For the owners ,it must be creative to attract the attention of people,strengthen the business climate and promote this area with lighting as well.
For the lighting design itself,there are many factors such as how to guide the flow of people safely and how to achieve the standard of illumination,how to control the light so that will be charming,comfortable and balance.It is said that commercial landscape lighting should be high brightness,and colorful , in fact, is a misunderstanding.
Practice has proved that too many brilliant colors and dynamic lighting give people a strong visual experience of discomfort.The color we use must be properly applied in accordance with the actual situation , combined with architectural features and surrounding environment.
Even the best script, without good actors , the effect is still poor ; in other words , no mater how outstanding a building is,there will be noting without light in the night. Fine feather makes the birds,so the light in the night is vital for walking street and building to make them more harmonious , creating a complementary atmosphere.
The biggest difference between arts and design is that design is more practical . Pay attention that the lighting design should be practical first, and then a beauty. Because of this ,the designer should guide the owners with a professional aesthetic and rational expressions .

2014年5月7日星期三

THE LED Floodlight

What is Flood Light?
The LED Flood Light use multi-chip LED integrated single module,with the first-class Aluminum alloy housing,acrylic glass cover and high efficiency imported LED driver,can be used indoor and outdoor . Floodlights are broad-beamed, high-intensity artificial lights. They are often used to illuminate outdoor playing fields while an outdoor sports event is being held during low-light conditions. More focused kinds are often used as a stage lighting instrument in live performances such as concerts and plays.For example,in the top tiers of many professional sports, it is a requirement for stadiums to have floodlights to allow games to be scheduled outside daylight hours. Evening or night matches may suit spectators who have work or other commitment earlier in the day. The main motivation for this is television marketing, especially in sports such as Gridiron which rely on TV rights money to finance the sport. Some sports grounds which do not have permanent floodlights installed may make use of portable temporary ones instead. Many larger floodlights (see bottom picture) will have gantries for bulb changing and maintenance. These will usually be able to accommodate one or two engineers.In the recent years there have been new developments and the LED technology has come a long way and now LED flood lights are bright enough to be used for illumination purposes on large sport fields.
Top 10 Benefits of LED Flood Lighting
1. Long Life
Long life time stands out as the number one benefit of LED lights. LED bulbs and diodes have an outstanding operational life time expectation of up to 100.000 hours. This is 11 years of continuous operation, or 22 years of 50% operation. If you leave on the LED fixture for 8h per day it would take around 20 years before youd have to replace the LED bulb.
LEDs are different to standard lighting: They dont really burn out and stop working like a standard light, moreover the lighting diodes emit lower output levels over a very long period of time and become less bright.
2. Energy Efficiency
Todays most efficient way of illumination and lighting, with an estimated energy efficiency of 80%-90% when compared to traditional lighting and conventional light bulbs. This means that about 80% of the electrical energy is converted to light, while a ca. 20% is lost and converted into other forms of energy such as heat.
With traditional incandescent light bulbs who operate at 20% energy efficiency only, a 80% of the electricity is lost as heat. Imagine the following scenario:
If you use traditional lighting and have an electricity bill of e.g US$ 100, then US$ 80 of that money has been used to heat the room, not to light it! Using LED illumination with 80% efficiency, the electricity costs would be around US$ 20 and youd have saved around US$ 80.
The long operational life time acts as a multiplicator and helps achieve even more energy efficiency, especially large scale and when thinking in terms of urban infrastructure projects, such as cities, railroads and airports.
Think of e.g an airport using energy efficient LED lighting exclusively and achieving a 30% power consumption reduction in comparison with an airport using conventional lighting technology.
Because the long life span of LED lights, also the maintenance work - think of all the work and energy it would take to purchase, stock and change the conventional light bulbs of an airport - youll see that you can make significant energy savings also when it comes to maintenance and replacement due to the long operational life times of LED lighting.
3. Ecologically Friendly
LED lights are free of toxic chemicals. Most conventional fluorescent lighting bulbs contain a multitude of materials like e.g mercury that are dangerous for the environment.

LED lights contain no toxic materials and are 100% recyclable, and will help you to reduce your carbon footprint by up to a third. The long operational life time span mentioned above means also that one LED light bulb can save material and production of 25 incandescent light bulbs. A big step towards a greener future!
4. Durable Quality
LEDs are extremely durable and built with sturdy components that are highly rugged and can withstand even the roughest conditions.

Because LED lights are resistant to shock, vibrations and external impacts, they make great outdoor lighting systems for rough conditions and exposure to weather, wind, rain or even external vandalism, traffic related public exposure and construction or manufacturing sites.
5. Zero UV Emissions
LED illumination produces little infrared light and close to no UV emissions.

Because of this, LED lighting is highly suitable not only for goods and materials that are sensitive to heat due to the benefit of little radiated heat emission, but also for illumination of UV sensitive objects or materials such a in museums, art galleries, archeological sites etc.
6. Design Flexibility
LEDs can be combined in any shape to produce highly efficient illumination. Individual LEDs can be dimmed, resulting in a dynamic control of light, color and distribution. Well-designed LED illumination systems can achieve fantastic lighting effects, not only for the eye but also for the mood and the mind:

LED mood illumination is already being used in airplanes, classrooms and many more locations and we can expect to see a lot more LED mood illumination in our daily lives within the next few years.
7. Operational in Extremely Cold or Hot Temperatures
LED are ideal for operation under cold and low outdoor temperature settings. For fluorescent lamps, low temperatures may affect operation and present a challenge, but LED illumination operates well also in cold settings, such as for outdoor winter settings, freezer rooms etc.
8. Light Dispersement
LED is designed to focus its light and can be directed to a specific location without the use of an external reflector, achieving a higher application efficiency than conventional lighting. Well-designed LED illumination systems are able to deliver light more efficiently to the desired location.
9. Instant Lighting & Frequent Switching
LED lights brighten up immediately and when powered on, which has great advantages for infrastructure projects such as e.g traffic and signal lights.

Also, LED lights can switched off and on frequently and without affecting the LEDs lifetime or light emission. In contrast, traditional lighting may take several seconds to reach full brightness, and frequent on/off switching does drastically reduce operational life expectancy.
10. Low-Voltage
A low-voltage power supply is sufficient for LED illumination. This makes it easy to use LED lighting also in outdoor settings, by connecting an external solar-energy source and is a big advantage when it comes to using LED technology in remote or rural areas.

Will LED lights damage our eyes?


LED lights, an invention to replace traditional lighting,can save money, time and the environment. However from 2008,the saying about LED lights cause damage to human eyes has never stop from all kinds of research by the authorities.So here in my blog Id like to do a summary.
Why the LED light can do harm to our eyes?
Light emitting diodes (LED) are made from crystals that may contain materials such as phosphorous in order to produce a distinct color. Overlapping colors, particularly the primary colors of red, blue and green, produce "white" light. No industry standard exists for brightness levels, but many manufacturers use the terms "super-bright" and "ultra-bright" to describe LED bulb intensity. Eyes are not designed to look directly at light — they are designed to see with light, isnt  it? Besides,blue LED light bulbs are the most utilized color of LEDs, and are used on everything from cell phones to television sets to medical equipment. Blue light is the hardest for the eye to focus on. We actually see a halo around bright blue light. Blue light scatters more inside the eyeball than other colors, producing more glare, more eyestrain and more fatigue. Intense blue light can cause damage to the retina, because blue is the hardest color for the retina to handle.
Dont be afraid ,why?
After all,we know that not only the glare,but also the blue light can be harmful to our eyes.It is said that LEDs produce light at the same frequency range as sunlight.Are you afraid of sunlight?Of cause yes,haha...but we barely see the sunlight directly,because it is not comfortable.So does it with the LED lights.Whats more,the housing of the LED light is design to protect our eyes from the intense brightness,low down the blue light which will not damage our retina,as well as looks beautiful.
Some advice for you.
Although the damage can be low down,it is still necessary for us to do something to protect out eyes,as our humans have their eyes open for around 6,000 hours a year, and most of this time they are exposed to artificial light.
Five eye exercises to help you maintain strong, healthy vision.
1. Computer users should take regular screen breaks, ideally every 30 minutes. During breaks, look to the distance or close your eyes for a few seconds in order to rest them.
2. People often find their eyes dry out because they blink less at a computer. To avoid this, try blinking every time you hit the return key.
3. The glands in our eyes can sometimes get blocked, which can contribute to dry eyes. To reduce this, cover your eyes with a hot flannel for a few minutes and then massage along the eye lids. Try to do this daily. Taking supplements such as good quality omega 3 oils can also help to improve tear function.
4. Some people find focusing on close-up tasks difficult. This may be due to slight weaknesses in our convergence eye muscles. Hold a pen around 40cm from your nose, then slowly move it closer until you can see it double. Do this three to four times then close your eyes for a few minutes or look in the distance to rest your eyes. Try to do this exercise little and often.
5. Hold some small text around 10-20cm away. It could be the page of a book or a food label, just make sure you can read it clearly. Then look at some text in the distance, maybe on a sign or the text/subtitles on the TV. Read one line of text close to you and then a line of text in the distance. Repeat this five to ten times. Once you have completed the exercise, rest your eyes for a few minutes by shutting them or looking in the distance.
Despite doubting , we should still set guidelines when using smartphones and tablets. 
Set your device to auto brightness.
Hold your tablet or smartphone at arms length (or about 70cm) from your eyes.
Make the font bigger to stop strain on the eyes.
Only use the device for a couple of hours a day in one sitting. Then take a break and come back to it later.