How is the brightness of light graded?

The brightness of light is generally distinguished by brightness.

1. Luminance refers to the brightness of the luminous surface. The ratio of the luminous intensity of the luminous surface in the specified direction to the area of ??the luminous surface perpendicular to the specified direction. The unit is candela/square meter.

2. Brightness: The brightness of a surface, represented by L, which is the luminous flux reflected from a surface. Different objects have different reflection coefficients or absorption coefficients for light. The most commonly used unit of illumination is candela.

3. 1_Candlelight is the luminous flux received on a one square foot plane one foot away from the standard candlepower. If the metric unit is used, the meter is used as the standard, and the illumination is expressed in meter candlelight (metrecandle), that is, 1 meter candlelight is the illumination on an area of ??one square meter one meter away from the standard candlelight. 1 meter candlelight is equal to 0.0929_candlelight.

4. The relationship between brightness and illuminance is: L=R×E [Formula 6-1] where L is brightness, R is reflection coefficient, and E is illuminance. Therefore, when the reflection coefficient of an object's surface and its surface illumination are known, the brightness can be calculated.

Extended information:

1. Incandescent lamp

An electric light source that heats the tungsten filament in the lamp to an incandescent state and uses thermal radiation to emit visible light. It is mainly composed of glass bulb, filament, wire, sensing column, lamp holder, etc. The advantages are that it is close to sunlight, has pleasant light color, continuous spectrum, high color rendering, and an index of above 95. It is suitable for artistic lighting and decorative lighting. The disadvantages are low light efficiency, low color temperature in the working atmosphere, large power consumption, and short lifespan of about 1,000 hours.

2. Halogen lamps

Halogen bulbs are referred to as halogen bulbs or halogen lamps. They are also called tungsten halogen bulbs and quartz bulbs. They are an improved version of incandescent lamps. At high temperatures, the sublimated tungsten wire reacts chemically with halogen, and the cooled tungsten will re-solidify on the tungsten wire, forming a balanced cycle to avoid premature breakage of the tungsten wire. Halogen lamps not only inherit the advantages of good color rendering of incandescent lamps, but also have longer life and higher luminous efficiency than incandescent lamps.

3. Fluorescent lamps

Fluorescent lamps are low-pressure mercury lamps, also known as fluorescent lamps. They are composed of lamp tubes and inductive ballasts. Phosphor plays a key role in the quality of fluorescent lamps. The mercury vapor in the lamp tube releases ultraviolet rays after being energized, and the phosphor absorbs ultraviolet rays and emits visible light. Common fluorescent lamps include straight tube fluorescent lamps, colored straight tube fluorescent lamps, ring fluorescent lamps, and single-ended compact energy-saving fluorescent lamps.

The advantages are high luminous efficiency, diverse color temperatures, and longer service life, about 2500-3500 hours. The disadvantages are spectral discontinuity, light flickering and mercury pollution.

4. Energy-saving lamps

Energy-saving lamps are also called energy-saving light bulbs, electronic light bulbs, compact fluorescent lamps and integrated fluorescent lamps. They refer to fluorescent lamps and ballasts combined into a whole. Lighting equipment.

The advantages are compact structure, small size, high luminous efficiency, energy saving, long service life, 6-10 times that of incandescent lamps. The disadvantage is that the color rendering index is low and the electronic ballast is easily damaged. Suitable for living room lighting, office lighting, industrial lighting, hotels, shopping malls and other places.

5. LED light

LED is the abbreviation of light-emitting diode. It is a solid-state semiconductor component that directly converts electrical energy into light energy. Advantages: More energy-saving. The energy consumption of white LED is 1/10 of incandescent lamp and 1/4 of energy-saving lamp. The service life is longer, up to more than 100,000 hours. No mercury pollution, more environmentally friendly.

LED lights should pay attention to heat dissipation. If the heat dissipation is not good, the service life will be affected. In addition, when purchasing LED lights, you must choose a reliable brand and confirm that the color rendering index is above 80.