Antireflection coating film and antireflection coating material for optical element and optical element

An optical coating film material for an optical element,

• comprising:
• an organic solvent;
• first particles having a refractive index (nd) of 2.2 to 3.5 for the d-line and an average particle size of 10 nm to 70 nm;
• second particles composed of at least one of silica and sericite,
• a colorant soluble in the organic solvent;
• and
• a resin,
• wherein with respect to a solid content excluding the organic solvent, a first particle content is in the range of 10% by weight to 35% by weight, and a second particle content is in the range of 1% by weight to 11% by weight,
• wherein the optical coating film material is a light-shielding coating and
• wherein a ratio of the minimum absorbance to the maximum absorbance (minimum absorbance/maximum absorbance) of the optical coating film material for the optical element in the wavelength range of 400 nm to 700 nm is 0.7 or more.

An optical element comprising:

• a substrate composed of an optical material;
• and
• an optical coating film being provided on a portion of a circumferential surface of the substrate,
• the optical coating film comprising:
• first particles having a refractive index (nd) of 2.2 to 3.5 for the d-line and an average particle size of 10 nm to 70 nm;
• second particles composed of at least one of silica and sericite,
• a colorant;
• and
• a resin,
• wherein a first particle content with respect to the optical coating film is in the range of 10% by weight to 35% by weight, and a second particle content with respect to the optical coating film is in the range of 1% by weight to 11% by weight,
• wherein the optical coating film is a light-shielding coating film, and
• wherein a ratio of the minimum absorbance to the maximum absorbance (minimum absorbance/maximum absorbance) of the optical coating film for an optical element in the wavelength range of 400 nm to 700 nm is 0.7 or more.