Lens and method for manufacturing lens

1. A lens for an eyewear, comprising:

a power source;

a detection section operated by a user of the eyewear;

a first substrate having a main surface, the first substrate being transparent;

a second substrate disposed opposite to the main surface and having a transmittance with respect to a light in a predetermined wavelength range, the transmittance being different from that of the first substrate;

an electrical element provided between the first substrate and the second substrate, including a liquid crystal layer, and having a refractive index which is changed by electrical control;

an adhesive layer provided between the first substrate and the second substrate; and

a control section changing the refractive index of the electrical element by applying a voltage of the power source when the detection section is operated by the user,

wherein:

the first substrate has a different thickness dimension in a direction of an optical axis of the lens depending on a position, and

the second substrate has the same thickness dimension in the direction of the optical axis throughout, is arranged farther from the user of the eyewear than the first substrate when the user wears the eyewear, and is kneaded an additive that is not included in the first substrate and makes the transmittance different from a transmittance of the first substrate.

2. The lens according to claim 1 , wherein

the additive includes a photochromic compound.

3. The lens according to claim 2 , wherein

in a case where a state in which the second substrate does not develop color is a normal state and a state in which the second substrate develops color by irradiating the second substrate with ultraviolet rays having a wavelength of 365 nm from a position of 155 mm in height for 10 minutes is a colored state,

the transmittance of the second substrate with respect to a light having a wavelength of 380 nm is 8% or less in the colored state,

an amount of change in hue ΔE*ab calculated from the following equation (A) based on L 1 *, a 1 * and b 1 * of the second substrate in the normal state and L 2 *, a 2 * and b 2 * of the second substrate in the colored state is 15 or more, and

an amount of change in hue ΔE*ab calculated from the following equation (A) based on L 1 *, a 1 * and b 1 * of the second substrate in the normal state and L 3 *, a 3 * and b 3 * of the second substrate after the second substrate in the colored state is left in a dark place for 10 minutes is less than 10%

Δ E*ab =[(Δ L *) 2 +(Δ a *) 2 +(Δ b *) 2 ] 1/2   (Equation A).

4. The lens according to claim 1 , wherein

the additive includes a selective absorber which selectively absorbs light in a wavelength range of 380 nm or more and 500 nm or less.

5. The lens according to claim 4 , wherein:

the selective absorber includes a benzotriazole-based selective absorber which absorbs ultraviolet rays, and

a light cut rate of the second substrate with respect to a light having a wavelength of 400 nm is 99.8% or more.

6. The lens according to claim 4 , wherein:

the selective absorber includes an ultraviolet absorber having a maximum absorption wavelength of 350 nm or more and 370 nm or less when dissolved in a chloroform solution, in a same composition as the second substrate having a thickness of 2 mm,

a light transmittance measured in the same composition as the second substrate having the thickness of 2 mm with respect to a light having a wavelength of 440 nm is 80% or more,

a light transmittance measured in the same composition as the second substrate having the thickness of 2 mm with respect to a light having a wavelength of 420 nm is 70% or less, and

a light transmittance measured in the same composition as the second substrate having the thickness of 2 mm with respect to a light having a wavelength of 410 nm is 10% or less.

7. The lens according to claim 6 , wherein

the ultraviolet absorber includes at least one compound of a benzotriazole-based compound, a benzophenone-based compound, and a salicylic ester-based compound.

8. The lens according to claim 7 , wherein

the ultraviolet absorber is a benzotriazole-based compound comprised of 2-(2-hydroxy-3-t-butyl-5-methylphenyl)-chlorobenzotriazole.

9. The lens according to claim 1 , wherein

the additive includes a rare earth metal compound or an organic dye.

10. The lens according to claim 9 , wherein:

the additive includes a rare earth metal compound or an organic dye having an absorption maximum wavelength in a wavelength region between 440 and 580 nm, and

a light transmittance with respect to a light having a wavelength of 580 nm is 60% or more and 90% or less.

11. The lens according to claim 1 , wherein

the adhesive layer is comprised of a photocuring adhesive.