Optical sheet, light-emitting device, method for manufacturing optical sheet, and method for manufacturing light-emitting device

An optical sheet comprising:

• a light-diffusing layer for diffusing incident light by diffracting at least a portion of the incident light,
• wherein the light-diffusing layer includes a plurality of first microscopic regions and a plurality of second microscopic regions,
• the plurality of first microscopic regions and the plurality of second microscopic regions are configured to produce a phase difference between light passing through the plurality of first microscopic regions and light passing through the plurality of second microscopic regions,
• when light incident on the light-diffusing layer at an angle greater than a critical angle accounts for 50% or more of a total light intensity of light incident on the light-diffusing layer, the plurality of first microscopic regions and the plurality of second microscopic regions form a pattern having a spatial frequency component that peaks between spatial frequencies of 0.055/(λ×n) and 0.45/(λ×n), inclusive, where λ is a central light emission wavelength of light incident on the light-diffusing layer and n is a refractive index of a layer in contact with a side of the light-diffusing layer from which light is emitted, and
• a center direction of emission directions of diffuse light diffused by the light-diffusing layer is away from an emission direction of non-diffused light that is refracted according to Snell's law upon impinging on the light-diffusing layer but passes through the light-diffusing layer without being diffused by the light-diffusing layer.

A light-emitting device comprising:

• a light-emitting unit configured to emits light;
• and
• a light-diffusing layer on which light from the light-emitting unit is incident,
• wherein the light-diffusing layer includes a plurality of first microscopic regions and a plurality of second microscopic regions,
• the plurality of first microscopic regions and the plurality of second microscopic regions are configured to produce a phase difference between light passing through the plurality of first microscopic regions and light passing through the plurality of second microscopic regions,
• the plurality of first microscopic regions and the plurality of second microscopic regions form a pattern having a spatial frequency component that peaks between spatial frequencies of 0.068/(λ×n) and 2.8/(λ×n), inclusive, where λ is a central light emission wavelength of light incident on the light-diffusing layer and n is a refractive index of a layer in contact with a side of the light-diffusing layer from which light is emitted, and
• a center direction of emission directions of diffuse light diffused by the light-diffusing layer is away from an emission direction of non-diffused light that is refracted according to Snell's law upon impinging on the light-diffusing layer but passes through the light-diffusing layer without being diffused by the light-diffusing layer.

A light-emitting device comprising:

• a light-emitting unit configured to emits light;
• and
• a light-diffusing layer on which light from the light-emitting unit is incident,
• wherein the light-diffusing layer includes a plurality of first microscopic regions and a plurality of second microscopic regions,
• the plurality of first microscopic regions and the plurality of second microscopic regions are configured to produce a phase difference between light passing through the plurality of first microscopic regions and light passing through the plurality of second microscopic regions,
• when light incident on the light-diffusing layer at an angle greater than a critical angle accounts for 50% or more of a total light intensity of light incident on the light-diffusing layer, the plurality of first microscopic regions and the plurality of second microscopic regions form a pattern having a spatial frequency component that peaks between spatial frequencies of 0.055/(λ×n) and 0.45/(λ×n), inclusive, where λ is a central light emission wavelength of light incident on the light-diffusing layer and n is a refractive index of a layer in contact with a side of the light-diffusing layer from which light is emitted, and
• a center direction of emission directions of diffuse light diffused by the light-diffusing layer is away from an emission direction of non-diffused light that is refracted according to Snell's law upon impinging on the light-diffusing layer but passes through the light-diffusing layer without being diffused by the light-diffusing layer.