Blue enhancer glasses

A wearable device, comprising:

• one or more windows positioned to allow light from a light source to propagate toward a position of a wearer's eyes;
• and
• a spectral filter that comprises a coating positioned on one or more sections of the one or more windows,
• wherein the spectral filter includes a multi-layer stack of dielectric material with alternate high and low indices of refraction such that a layer having a high index of refraction is positioned above or below a layer having a low index of refraction,
• wherein a number of the layers and a thickness of each layer are selected to provide designed transmission and blocking characteristics to allow circadian-active spectra to reach the wearer's eyes while blocking spectral content other than the circadian-active spectra,
• wherein the designed transmission and blocking characteristics include a contiguous transmission region that extends from 455 nm to 560 nm, a first contiguous blocking region that extends from 455 nm to 300 nm or below 300 nm, and a second contiguous blocking region that extends from 560 nm to at least 750 nm, all with a ±2 nm tolerance,
• wherein the spectral filter is configured to block 80-100% of spectral content in each of the contiguous blocking regions, and transmit 98%-100% of spectral content in the contiguous transmission region.

A spectral filter for use in an eyewear for restoring circadian rhythm, comprising:

• a multi-layer stack coating on a substrate, the multi-layer stack including a plurality of layers of dielectric material with alternate high and low indices of refraction such that a layer having a high index of refraction is positioned above or below a layer having a low index of reflection,
• wherein a number of the layers and a thickness of each layer are selected to provide designed transmission and blocking characteristics to allow circadian-active spectra to be transmitted through the spectral filter,
• wherein the designed transmission and blocking characteristics include a contiguous transmission region within 455-560 nm band of wavelengths with a tolerance to within at least ±5 nm, and two contiguous blocking regions, a first one of the contiguous blocking regions extending below 455 nm and a second one of the contiguous blocking regions extending above 560 nm,
• wherein each of the contiguous blocking regions blocks 80-100% of spectral content in the corresponding blocking region,
• wherein the contiguous transmission region transmits 98-100% of spectral content in the transmission region, and
• wherein the contiguous transmission region extends from 455 nm to 495 nm, the first contiguous blocking region extends from 455 nm to 300 nm or below 300 nm, the second contiguous blocking region extends from 495 nm to at least 700 nm, all with a ±2 nm tolerance.

A spectral filter for use in an eyewear for restoring circadian rhythm, comprising:

• a multi-layer stack coating on a substrate, the multi-layer stack including a plurality of layers of dielectric material with alternate high and low indices of refraction such that a layer having a high index of refraction is positioned above or below a layer having a low index of refraction,
• wherein a number of the layers and a thickness of each layer are selected to provide designed transmission and blocking characteristics to allow circadian-active spectra to be transmitted through the spectral filter,
• wherein the designed transmission and blocking characteristics include a contiguous transmission region that extends from 455 nm to 560 nm, a first contiguous blocking region that extends from 455 nm to 300 nm or below 300 nm, and a second contiguous blocking region that extends from 560 nm to at least 750 nm, all with a ±2 nm tolerance,
• wherein each of the contiguous blocking regions blocks 80-100% of spectral content in the corresponding blocking region, and
• wherein the contiguous transmission region transmits 98-100% of spectral content in the transmission region.