IR transmitting coating for electro-optic element

An electrochromic mirror system comprising:

• an electrochromic element comprising:
• a first substrate comprising a first surface and a second surface;
• a second substrate comprising a third surface and a fourth surface,
• wherein the first substrate and the second substrate form a cavity between the second surface and the third surface;
• an electrochromic medium contained in the cavity;
• a transflective dielectric coating disposed at the fourth surface, wherein the transflective dielectric coating comprises a multi-layer stack comprising alternating high-index (H) material and low-index (L) material;
• and
• an image sensor located rearward of the electrochromic element and directed toward the fourth surface, wherein a near infrared transmittance through the electrochromic element comprises a wavelength from 800 nm to 940 nm and a visible transmittance through the electrochromic element, wherein the near infrared transmittance exceeds the visible transmittance and the visible transmittance is at least 20% through the electrochromic element and wherein the visible transmittance of the electrochromic element comprises a shift in a green-red color coordinate (a*) and blue-yellow color coordinate (b*) of less than 5.

A method for operating an electrochromic mirror system comprising an electrochromic element, the electrochromic element comprising a first substrate comprising a first surface and a second surface, a second substrate comprising a third surface and a fourth surface, and an electrochromic medium disposed between the first substrate and the second substrate, wherein the electrochromic medium comprises a transflective dielectric coating disposed at the fourth surface, the method comprising:

• emitting an output emission of a near infrared light at a wavelength approximately from 800 nm to 940 nm from an emitter through the electrochromic element and the transflective dielectric coating;
• transmitting the near infrared light reflected from a subject through the electrochromic element and the transflective dielectric coating;
• transmitting a visible light comprising wavelengths of light from 400 nm to 700 nm through the electrochromic element and the transflective dielectric coating concurrently with the near infrared light, wherein the transmission of the near infrared light exceeds a visible transmittance and an average transmission of the visible light is at least 20%;
• and
• receiving via an image sensor the near infrared light and the visible light transmitted through the electrochromic element and the transflective dielectric coating.