Target unit of machine vision system, target assembly and machine vision system

A target assembly, comprising:

• a housing, provided with a receiving groove;
• and, a target unit,
• wherein the target unit comprises:
• a protective plate, comprising a connection surface;
• a light absorbing layer;
• and
• a light reflecting layer, the light reflecting layer being connected to the light absorbing layer, one of the light absorbing layer and the light reflecting layer comprising a preset pattern and being connected to the protective plate through the connection surface, and a surface that is of the other of the light absorbing layer and the light reflecting layer and that faces away from the protective plate being an outer surface of the target unit;
• wherein
• the light absorbing layer comprises the preset pattern, the light absorbing layer being connected to the protective plate through the connection surface;
• the light reflecting layer is connected to the light absorbing layer, a surface of the light reflecting layer that faces away from the protective plate being the outer surface of the target unit;
• and
• the pattern comprises a pattern light absorbing region and a pattern light transmission region;
• wherein
• the light absorbing layer comprises a film negative, the film negative being connected to the protective plate through the connection surface;
• the protective plate being mounted to the housing, the protective plate being received in the receiving groove, and the connection surface facing away from an opening of the receiving groove.