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IntroductionLight is the single most important variable with respect to plant growth and development and is often the most limiting factor. Therefore, the use of grow lights in commercial greenhouses is beneficial for plants and growers. The reason for using دیدن لینک ها برای شما امکان پذیر نیست. لطفا ثبت نام کنید یا وارد حساب خود شوید تا بتوانید لینک ها را ببینید.
varies and includes increasing light levels for plant photosynthesis or altering photoperiod. The duration of light a plant perceives is photoperiod. The different lighting sources that growers can use include incandescent (INC) lamps, tungsten-halogen lamps, fluorescent lamps and high intensity discharge (HID) lamps. Light emitting diodes (LED) are fourth generation lighting sources and are an emerging technology in horticulture.
LED Advantages

Energy efficient

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Easy installation
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More durable
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Longer lifetime (less lamp changes)
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Low heat emission
[size=medium]Before choosing دیدن لینک ها برای شما امکان پذیر نیست. لطفا ثبت نام کنید یا وارد حساب خود شوید تا بتوانید لینک ها را ببینید.
, several factors such as costs, efficiency, total energy emissions, life expectancy, light quality, light quantity, light duration and effect on plant growth and flowering should be considered. This Fact Sheet provides information about دیدن لینک ها برای شما امکان پذیر نیست. لطفا ثبت نام کنید یا وارد حساب خود شوید تا بتوانید لینک ها را ببینید.
s for use in plant production.[size=medium][size=medium]Design and Function[size=medium]The design of LEDs varies and there are three main structural types, which are lead-wire, surface mounted and high-power LED. Despite the different designs, each type is mounted on a printed circuit board; therefore, LEDs function like computer chips. دیدن لینک ها برای شما امکان پذیر نیست. لطفا ثبت نام کنید یا وارد حساب خود شوید تا بتوانید لینک ها را ببینید.
are solid-state semiconductors and when turned on or off, the action is instant. As for life expectancy (dim to about 70 percent from initial installation), LEDs can operate up to 50,000 hours. It is not necessary to replace single diodes or lamps constantly because LEDs do not burn out. Factors such as design, materials used and heat release affect life expectancy. Another important feature of LEDs is that heat does not escape from the surface, but through a heat sink which allows for close proximity between plants and LEDs. As for consumption of energy, LEDs are more efficient and use less energy than any other traditional greenhouse lights. In addition, operating costs and carbon emissions are lowered when using LEDs.[size=medium]
[size=medium]Infrared Heat Lamps vs. LED Light Therapy Devices[size=medium]Are red light therapy devices different from infrared (IR) heat lamps? Yes, a lot different, and one of the big reasons is right in the name: heat.[size=medium]دیدن لینک ها برای شما امکان پذیر نیست. لطفا ثبت نام کنید یا وارد حساب خود شوید تا بتوانید لینک ها را ببینید.
s are designed to induce heat stress on a user. The heat is the point. The problem is that excess heat can potentially cause damage to your skin. By contrast, high-quality LED light therapy devices—like Joovv—give off very little heat, and have been found safe, effective, and free of side effects in numerous clinical trials.[size=medium]Even if heat lamps could deliver clinical results similar to light therapy, the burn risks are not worth it. Beyond the heat dangers, heat lamps simply do not offer the clinically-proven wavelengths or medical-grade power output of a high-quality LED device, which we will explain in more detail throughout this article.[size=medium]
[size=medium]Heat Lamps Do not Offer Clinically-Proven Wavelengths of Light[size=medium]Not all natural light is created equal; different wavelengths and colors within the light spectrum have different effects. And it is hardly a secret which wavelengths are effective for light therapy. Extensive research has shown that only a relatively narrow band of red and near infrared wavelengths impact your cells and have a significant therapeutic effect.[size=medium]
[size=medium]دیدن لینک ها برای شما امکان پذیر نیست. لطفا ثبت نام کنید یا وارد حساب خود شوید تا بتوانید لینک ها را ببینید.
s produce a wide range of wavelengths, but as the graph below shows, the wavelength curve builds to its peak output around 1100 nm. [3][size=medium]Less than 1% of the energy from heat lamps is delivered from 600-660 nm, and only about 2% is delivered in the entire 810-880 nm range. In total, these wavelengths only represent about 3% of the total energy delivered by a heat lamp bulb. In other words, 97% of wavelengths from a heat lamp fall outside of the wavelength range known to produce the greatest health benefits.[size=medium]
[size=medium]Infrared Heat Lamps Lack Power and Effectiveness[size=medium]In addition to heat lamps delivering inferior wavelengths, they do not offer medical-grade power like a high quality LED light therapy device.[size=medium]The total power output—sometimes referred to as irradiance—from a device also directly impacts the time required for treatments. Lower-powered products like دیدن لینک ها برای شما امکان پذیر نیست. لطفا ثبت نام کنید یا وارد حساب خود شوید تا بتوانید لینک ها را ببینید.
s take way longer to produce benefits, if ever. Imagine filling up your water bottle from a dripping faucet—it will fill up eventually, but you will waste a lot of time in the process.[size=medium]
[size=medium]دیدن لینک ها برای شما امکان پذیر نیست. لطفا ثبت نام کنید یا وارد حساب خود شوید تا بتوانید لینک ها را ببینید.
is a type of electromagnetic radiation that makes black-light posters glow, and is responsible for summer tans — and sunburns. However, too much exposure to UV radiation is damaging to living tissue.[size=medium]Electromagnetic radiation comes from the sun and transmitted in waves or particles at different wavelengths and frequencies. This broad range of wavelengths is known as the electromagnetic (EM) spectrum. The spectrum is generally divided into seven regions in order of decreasing wavelength and increasing energy and frequency. The common designations are radio waves, microwaves, infrared (IR), visible light, ultraviolet (UV), X-rays and gamma-rays.[size=medium]
[size=medium]Ultraviolet (UV) light falls in the range of the EM spectrum between visible light and X-rays. It has frequencies of about 8 × 1014 to 3 × 1016 cycles per second, or hertz (Hz), and wavelengths of about 380 nanometers (1.5 × 10−5 inches) to about 10 nm (4 × 10−7 inches).