In the first half of this article, we mainly introduced the 6 features of an LED, including light color, forward current, forward voltage, reverse voltage, color temperature, luminous tensity. Here we’ll complete the topic with talking over the luminous flux, illuminance, color rendering, light emitting angle, glares, and service life of LED.
LED luminous flux refers to the amount of light emitted per unit time, in units of lumens (lm). Luminous flux describes the total amount of light emitted by a light source, which is equivalent to light power. The greater the luminous flux of a light source, the more light is emitted.
Factors affecting LED luminous flux
LED luminous flux is affected by current and temperature. As the current increases, the luminous flux of the LED will also increase, but as the temperature rises, the luminous flux will decrease.
LED light efficiency range
The luminous efficiency of LED fluorescent lamps can generally reach >80lm/W, and the luminous efficiency of LED bulbs can generally reach >75lm/W.
The illuminance of an LED depends not only on its own light intensity, but also on the distance between the light source and the illuminated surface. Illuminance is a measure of the luminous flux received per unit area and is usually used to evaluate the brightness of the light. In the application of LEDs, understanding the illuminance is crucial to ensure appropriate lighting conditions and avoid over- or under-lighting.
As an efficient and energy-saving light source, LEDs have a wide range of applications, including but not limited to home lighting, commercial lighting, industrial lighting, municipal street lights, tunnel lights, landscape lighting, etc. Different types of LED products, such as ordinary brightness LEDs, high brightness LEDs (G-LEDs), and ultra-high brightness LEDs, have different application scenarios and illuminance requirements. For example, ultra-high brightness LEDs are often used in special lighting fields, such as automotive headlights, special work lighting, and military fields. These applications have high requirements for illuminance to ensure visibility and safety in specific environments.
In short, the illuminance of LEDs is an important performance indicator that directly affects the effect of LEDs in practical applications. Understanding and mastering the illuminance of LEDs is of great significance for the correct selection and use of LED products.
LED color rendering refers to the ability of LED to restore color, which is mainly measured by the color rendering index (CRI). The range of the color rendering index (CRI) is from 0 to 100. The closer the value is to 100, the better the color rendering of the LED, that is, the closer the color restoration of the surface of the illuminated object is to the natural original color. Light sources with high color rendering can better display colors, making the colors seen more realistic; while light sources with low color rendering may cause large deviations in color performance.
Kinglight P3 Color Gamut Series LEDs offer high color rendering performance for cinema screens
In order to evaluate the color rendering of LED light sources, in addition to CRI, there are other evaluation methods, such as color quality index (CQS) and TV light consistency index (TLCI). CQS and TLCI evaluate the color quality of LED light sources and the requirements of TV cameras for lighting environments, respectively, providing a more comprehensive evaluation perspective.
Color Quality Index (CQS): CQS selects 15 saturated color samples and calculates the color difference between the measured light source and the reference light source illuminating the same set of standard color samples to evaluate the color quality of new white light sources such as LED. The calculation method of CQS has been enhanced in the weight of color difference to more accurately evaluate the fidelity and preference of color.
TV Light Consistency Index (TLCI): TLCI is a test standard specifically for studio lighting issued by the European Broadcasting Union (EBU). It fully considers the requirements of TV cameras for lighting environment and evaluates the compatibility of light sources with TV cameras by measuring and calculating the spectral energy distribution emitted by a light source.
In summary, the color rendering of LED is one of the important indicators for evaluating its lighting quality. Through various evaluation methods such as CRI, CQS and TLCI, the color reproduction ability of LED light sources and their performance in specific application scenarios can be comprehensively evaluated.
The light emitting angle of LED, in simple terms, is the scattering range of the light emitted by the LED light source in space. This angle has an important impact on the application effect of LED, and different application scenarios may require LED products with different emitting angles.
The emitting angle of LED mainly depends on factors such as its packaging method, lens design, and the amount of scattering agent added. Generally speaking, the emitting angle of LED can be divided into the following categories:
Highly directional LED: This type of LED has a smaller emitting angle, usually between 5° and 20°, or even smaller. They usually use pointed epoxy packaging or metal reflective cavity packaging, and no or little scattering agent is added, so the light is highly concentrated and has strong directionality. This type of LED is suitable for occasions where the direction of light needs to be precisely controlled, such as stage lighting, spotlights, etc.
Standard LED: This type of LED has a moderate emitting angle, generally between 20° and 45°, and there are also claims that its emitting angle is 20° to 60°. They are widely used in indicator lights, indoor lighting and other fields, which can not only ensure a certain lighting range, but also avoid too scattered light.
Scattering LEDs : These LEDs have a larger emitting angle, usually between 45° and 90°, or even larger, and a larger amount of scattering agent. The light they emit has a wide scattering range, making them suitable for applications that require large-area lighting, such as outdoor billboards, landscape lighting, etc.
In addition, there are some specially designed LED products, such as LED underground lamps, whose emitting angle range may be wider, ranging from 5° to 120°, to meet the needs of different application scenarios.
When choosing LED products, the emitting angle is an important consideration. According to the specific application scenarios and needs, choosing the right emitting angle can ensure that the LED light source can achieve the best performance and effect. At the same time, with the continuous advancement of technology and the continuous expansion of application fields, the emitting angle of LEDs will continue to be optimized and innovated.
Glares of LEDs generally occur in LED lighting, mainly manifested as excessive light intensity or uneven light distribution from LED light sources, which causes discomfort or visual fatigue in the human eye.
The main causes of LED glare include excessive brightness of LED lamps, light distribution and scattering problems caused by unreasonable lamp design, or dim ambient light.
The solution is usually to reasonably control the brightness of LED lamps, optimize the design of LED lamps, adjust the installation position of lamps, and appropriately improve the ambient light conditions.
Generally speaking, LEDs have a long service life, usually up to 50,000 hours or more, and some LED manufacturers even claim that their LEDs can work for 100,000 hours. Of course, this involves testing methods and specific testing standards.
The reason why LEDs are so durable is that they do not have the problem of filament melting. Tests have shown that LED lamps can still maintain 60% of their original brightness after 50,000 hours of operation.
The main factors affecting the service life of LEDs are the quality of the LEDs themselves and the way, conditions and environment in which they are used.
High-quality LEDs often have a longer service life; while frequent switching of LEDs, or using LEDs at high temperatures and with poor power supply stability will shorten the service life of LEDs.
