Feedback control device for photo-colorimetric parameters for a light box with color LEDs

An electronic feedback device for feedback control of photometric or colorimetric characteristics for a light box which illuminates optical-valve images, comprising:

• an electronic control circuit which controls at least a first and a second array of light-emitting diodes disposed in the light box,
• the first array of light emitting diodes emitting light in a first spectral band,
• the second array of light emitting diodes emitting light in a second spectral band;
• an electronic processing/computing unit driving the electronic control circuit;
• and
• optoelectronic devices for measuring photometric and colorimetric characteristics of the light-emitting diodes connected to the electronic processing/computing unit, said optoelectronic devices comprising a first optoelectronic assembly including:
• a first optoelectronic light-emitting diode identical to one light emitting diode of the first and second arrays of light emitting diodes in the light box;
• and
• a photosensitive sensor placed facing said first optoelectronic light-emitting diode, said first optoelectronic light emitting diode being controlled by the electronic control circuit,
• said first optoelectronic assembly comprising a structure which isolates the first optoelectronic assembly from external light said first optoelectronic assembly being placed in an environment close to that of the light box, and
• said electronic processing/computing unit comprising:
• a storage unit for storing setpoint values of the photometric and colorimetric parameters;
• a processing unit for processing the data coming from the photosensitive sensor, said processing unit being connected to the optoelectronic measurement devices;
• an electronic comparator for comparing the data coming from the processing unit with the setpoint values;
• and
• a control unit connected, on one side, to the electronic comparator and, on the other side, to the electronic control circuit for the arrays of light-emitting diodes, thereby making it possible to maintain the setpoint values of the photometric and colorimetric parameters.