Electrochromic device, optical filter, lens unit, imaging apparatus, window member, and driving method

An electrochromic device comprising:

• an electrochromic element including:
• a first electrode,
• a second electrode, and
• an electrochromic layer disposed between the first electrode and the second electrode;
• and
• a controller for the electrochromic element,
• wherein the electrochromic layer contains a cathodic electrochromic compound and a reducible substance,
• the reducible substance is a substance which substantially does not undergo a color change due to reduction and whose reductant is not oxidized,
• a reduction reaction of the reducible substance is less likely to occur than a reversible reduction reaction of the cathodic electrochromic compound and is more likely to occur than an irreversible reduction reaction of the cathodic electrochromic compound, and
• the controller is configured to control reduction of the reducible substance based on a charge balance of the electrochromic element.

A driving method for an electrochromic element including a pair of electrodes and an electrochromic layer disposed between the pair of electrodes, the driving method comprising:

• a detection step of detecting a charge balance between the pair of electrodes;
• and
• an application step of applying a voltage or a current to the electrochromic element based on a detection result in the detection step;
• wherein the voltage or the current in the application step is larger than a voltage or a current applied when the electrochromic element is colored.