High-power LED lamp bead parameters and design techniques

Brightness

The brightness of LEDs varies, affecting their prices:

- Bulb cups: generally have a brightness of 60-70lm.

- Bulb lights: typically range from 80-90lm.

Note: 1W brightness ranges from 90-130lm. 3W LEDs can reach up to 240-260lm, while 5W-500W LEDs integrate chips, using serial/parallel packaging, primarily determined by current, voltage, and series/parallel configurations.

- 1W red light: brightness is usually 50-55lm.

- 1W green light: brightness typically falls between 60-80lm.

- 1W yellow light: brightness generally ranges from 30-50lm.

- 1W blue light: brightness usually falls between 20-30lm.

LED lenses are usually made from materials such as PMMA, PC, optical glass, silicone gel (soft or hard). Larger angles result in higher light efficiency, and LEDs with smaller angles project light further.

2. Electrostatic Discharge (ESD) Resistance

LEDs with higher ESD resistance tend to have longer lifespans but come at a higher price. LEDs with an ESD rating above 700V are suitable for LED lighting applications.

3. Wavelength

Consistency in wavelength ensures consistent colors, hence a higher price. Manufacturers without LED spectrophotometers find it challenging to produce pure-colored products.

- White light: warm (color temperature 2700-4000K), natural (color temperature 5500-6000K), cool (color temperature above 7000K). Warm white is popular in Europe.

- Red light: wavelengths between 600-680, mainly used in stage lights. 690 approaches infrared.

- Blue light: wavelengths between 430-480, with 460 and 465 commonly used in stage lighting.

- Green light: wavelengths between 500-580, with 525 and 530 frequently used in stage lighting.

4. Leakage Current

LEDs are unidirectional conductive light emitters. LEDs with reverse current, known as leakage, have shorter lifespans and lower prices.

5. Emission Angle

Different LEDs have different emission angles, with special angles often commanding higher prices.

6. Lifespan

Lifespan is a key differentiator in quality. Long lifespans, determined by light decay, result in higher prices.

7. LED Chips

LED chips determine the emitter. Chips from different manufacturers lead to significant price differences, with Japanese and American chips generally more expensive than Taiwanese or Chinese ones.

8. Chip Size

Larger chips (measured by side length, typically 38-45mΩ) signify better quality and are priced higher, correlating positively with chip size.

9. Encapsulation Material

Ordinary LED encapsulation often uses epoxy resin. LEDs with UV-resistant and fire-retardant additives command higher prices. High-quality outdoor LED fixtures should be UV and fire-resistant.

10. Color Rendering Index (CRI)

For white light: 70-75 (neutral), 60-65 (warm). Different companies use varying phosphor powders, leading to different CRIs.

Electrical Light Source Design Techniques:

Every product requires unique designs suitable for specific purposes. The reliability of LED lighting design encompasses electrical safety, fire safety, environmental adaptability, mechanical safety, health safety, and the duration of safe use. From an electrical safety perspective, adherence to relevant international and national standards is essential. While Chinese national standards for LEDs may lag, the country provides product qualification testing. LEDs certified with international safety standards (like GS, CE, UL) and national product quality certifications command higher prices due to their reliable safety design. Consumers should meticulously verify the authenticity of certifications, as few manufacturers possess international safety certifications and national product qualifications.

Regarding health considerations, products designed with non-toxic materials command higher prices, particularly for indoor LED lighting. Consumers should avoid choosing LED fixtures with odors, as only a few LED manufacturers use non-toxic materials. Products emitting strong odors often have significantly lower prices. Professional analysis is necessary to identify toxins such as lead, mercury, cadmium, etc.

Environmental adaptability and safety entail reliable dust and moisture resistance, materials resistant to fire, UV, and low-temperature cracking, commanding higher prices for LED products. Technical parameters of LEDs mainly include luminous intensity, chromaticity, wavelength, and color temperature. The following provides a brief introduction to these parameters.

Luminous Intensity (IV):

Luminous intensity refers to the light flux emitted per unit solid angle and is measured in candelas (cd). Typically, light sources emit light flux at different intensities in different directions. The visible light radiation intensity in a specific direction per unit solid angle is termed luminous intensity.

Chromaticity:

Human perception of color is a complex process. To quantify color descriptions, the International Commission on Illumination (CIE) recorded visual sensations of radiation energy for different wavelengths by standard observers. This led to calculating the color matching functions for red, green, and blue primary colors, ultimately yielding the CIE 1931 Color Matching Function (x(λ), y(λ), z(λ)). This function allows for the quantification and control of color descriptions.

x, y: CIE 1931 Chromaticity Coordinates

However, due to the non-uniformity of the color space constructed by (x, y) chromaticity coordinates, making color differences difficult to quantify, in 1976, the CIE transformed the CIE 1931 coordinates to create a nearly uniform chromaticity space, termed CIE 1976 UCS (Uniform Chromaticity Scale). This allowed for quantifying color differences, represented by (u', v‘) chromaticity coordinates in percentage terms. The purity of a color describes the distance between the chromaticity coordinates of the test piece and the chromaticity coordinates of the light source 'E' to the spectrum trajectory of the test piece's main wavelength.

Please note, however, this representation method results in multiple different chromaticity points for the same main wavelength. Therefore, it's more meaningful when used for test pieces' chromatic points close to the spectrum trajectory, whereas it cannot describe the color characteristics of white LED in the same way.