Detailed explanation of projector performance indicators

The performance indicators of projectors are the signs to distinguish the grades of projectors, mainly including the following indicators:

light output
Refers to the light energy output by the projector, in "lumens" (lm). A physical quantity related to light output is brightness, which refers to the ratio of the light energy emitted by the screen surface exposed to light to the screen area. The commonly used unit of brightness is "lux" (lx, 1lx=1lm/m2). When the light output by the projector passes through a certain amount, the larger the projection area, the lower the brightness, and vice versa, the higher the brightness. The factors that determine the light output of the projector are the projection and screen area, performance and lens performance. Generally, the larger the screen area, the larger the light output. Projector lenses with liquid-coupled lenses perform well and projector light output can be increased accordingly.

Horizontal scan frequency
The movement of electrons on the screen from left to right is called horizontal scan, also called line scan. The number of scans per second is called the horizontal scanning frequency. The horizontal scanning frequency of the video projector is fixed, which is 15.625KHz (PAL system) or 15.725KHz (NTSC system) data and the scanning frequency of the graphics projector is not a frequency band; In this frequency band, the projector can automatically track the horizontal frequency of the input signal, and the phase-locked circuit can achieve complete synchronization with the horizontal frequency of the input signal. Horizontal scanning frequency is an important projector indicator to distinguish projector grades. Projectors with a frequency range of 15kHz-60kHz are often called data projectors. Those with an upper frequency limit of more than 60kHz are usually called graphic projectors.

Vertical scan frequency
The electron beam moves from top to bottom while scanning horizontally. This process is called vertical scanning. Each scan to form an image, the number of scans per second is called the vertical scan frequency, and the vertical scan frequency is also called the refresh frequency, which represents the number of times the image is refreshed per second. The vertical scanning frequency is generally not lower than 50Hz, otherwise the image will have a flickering feeling.