Mobile code reading device and code reading method

A code reading method for generating a code image by irradiating a specular workpiece surface to which a code is attached with planar light, receiving light specularly reflected by the workpiece surface, and diffusing and reflecting light emitted to a portion corresponding to the code, the code reading method comprising:

• a step of causing light emitted from a first light source to be incident on a diffuser;
• a step of causing the diffuser to diffuse the light;
• a step of irradiating the workpiece surface with the light diffused by the diffuser;
• a step of collecting, by a condenser lens, the light reflected by the workpiece surface;
• and
• a step of receiving the light collected by the condenser lens to generate the code image, wherein
• the diffuser has an inclined shape that gradually expands as a distance from the first camera increases, and diffuses the light emitted from the first light source to emit diffuse light toward the workpiece surface,
• a position and an angle of the diffuser are fixed with respect to the first camera to allow the first camera to receive the specularly reflected light from the workpiece surface in a state where the first camera is in focus on the workpiece surface, and
• the first light source emits the light toward the diffuser from a back or a front of a rear end of the diffuser or irradiates the diffuser with the light via a reflector provided on an optical path between the first light source and the diffuser to prevent the light source from being reflected on the first camera when the first camera receives the specularly reflected light.