• Spectrum

In the field of plant lighting, the spectrum is a crucial factor. Different spectral components have different impacts on plant growth and development. For example, red light (with a wavelength range of approximately 620 - 750nm) can promote plant photosynthesis. Especially in the light - reaction stage of photosynthesis, red light can be effectively absorbed by chlorophyll and other photosynthetic pigments, thereby improving photosynthetic efficiency. At the same time, red light also plays an important role in promoting the flowering and fruiting processes of plants. It can stimulate the differentiation and development of plant flower buds. Blue light (with a wavelength range of approximately 420 - 495nm) is also a necessary spectral component for plant growth. Blue light mainly affects plant morphogenesis. For example, it can make plant stems stronger and leaves thicker and also promote the synthesis of chlorophyll. During the plant seedling stage, appropriate blue - light irradiation can help the seedlings grow vigorously. The role of green light (with a wavelength range of approximately 495 - 570nm) in plant lighting is relatively complex. Although plants' absorption efficiency of green light is not as high as that of red light and blue light, green light can penetrate deeper into the plant canopy and regulate the light environment inside the plant. Moreover, a certain proportion of green light used in combination with red light and blue light can make plant growth more natural and avoid abnormal plant growth caused by a single spectral component.

• light intensity

In physics, light intensity refers to the luminous flux received per unit area and is used to measure the strength of light. Luminous flux refers to the radiant power that can be perceived by the human eye and represents the total amount of light emitted by a light source. The unit of light intensity is the candela (cd). One candela represents a luminous flux of one lumen emitted within a unit solid angle (1 steradian). For example, if a point - source light emits light uniformly in all directions, and the luminous flux in a certain direction is 1 lumen and the solid angle corresponding to this direction is 1 steradian, then the light intensity in this direction is 1 candela. In practical applications, the concept of light intensity is also important. For example, in lighting design, the light intensity required for different places needs to be considered to ensure sufficient illumination brightness. Places such as classrooms and offices have corresponding light - intensity standards to meet people's visual needs.

• Uniformity of light

Light uniformity refers to the degree of uniformity of light intensity, color, and distribution within a specific lighting area. It is an important indicator for measuring lighting quality. From the perspective of light intensity, ideal uniform lighting means that the light intensity values at various points in the area are similar, and there are no obvious bright spots or dark areas.

For example, in the lighting design of a conference room, if the light uniformity is good, then every corner of the conference room and every position on the conference table will have a relatively uniform brightness, and people can have a comfortable visual experience at any position in the room. In terms of color, light uniformity also requires that the color of light remains consistent within the lighting area. This is especially important for some places with high requirements for color accuracy, such as art galleries and museum exhibition halls. If the color of light is uneven, it may cause the colors of exhibits to look inconsistent and affect the audience's appreciation and understanding of the exhibits.

• Luminous efficacy

Luminous efficacy refers to the efficiency with which an electric light source converts electrical energy into visible light and is an important indicator for measuring the energy - saving performance of a light source. It is calculated as the ratio of luminous flux (unit: lumen, lm) to power consumption (unit: watt, W), and the unit is lumen per watt (lm/W). For example, a light bulb consumes 100 watts (W) of power and emits a luminous flux of 1500 lumens (lm), then its luminous efficacy is 1500 lm÷100 W = 15 lm/W. This means that for every watt of electrical energy consumed, this light bulb can emit 15 lumens of light.