Light-controlling element, display device and illumination device

摘要

A light-controlling element includes an illumination unit capable of controlling an amount of emitted light, and a light guide body on which the light emitted from the illumination unit is incident. The light guide body has a function of propagating the light while totally reflecting the light inside the light guide body, and the light guide body has a function of propagating the light emitted from the illumination unit at a plurality of different propagation angles inside the light guide body. The light guide body includes a plurality of light extraction regions having a function of extracting the light to the outside. At least two of the plurality of light extraction regions have different incidence angle ranges in which the light is capable of being extracted to the outside.

主权项

1. A light-controlling element comprising: an illumination unit capable of controlling an amount of emitted light; and a light guide body on which the light emitted from the illumination unit is incident, wherein the light guide body is configured to propagate the light while totally reflecting the light inside the light guide body, the light guide body is configured to propagate the light emitted from the illumination unit at a plurality of different propagation angles inside the light guide body, the light guide body includes a plurality of light extraction regions configured to extract the light to the outside, and at least two of the plurality of light extraction regions have different incidence angle ranges in which the light is capable of being extracted to the outside; wherein the light guide body includes a propagation angle changing unit that changes a propagation angle of the light so that an angle of incidence of light on one of the plurality of light extraction regions is smaller than an angle of incidence of light on the light extraction region closer to the illumination unit than the one light extraction region; and the propagation angle changing unit includes an inclined surface obtained by inclining at least one of a first surface having the plurality of light extraction regions of the light guide body provided therein and a second surface opposing the first surface, and the inclined surface has a slope to approach the first or second surface along the propagation direction of the light; wherein the light control-controlling element satisfies expressions (1), (2), and (3):
(t/tan φ)*2≦d1  (1) 0≦d2≦(t/tan(φ+2ε)  (2) t/tan(φ+2ε)≦d3  (3) when a thickness of the light guide body is t, a size of the propagation angle changing unit in the propagation direction of the light is d1, a distance from an end close to the illumination unit of the propagation angle changing unit to an end close to the illumination unit of the light extraction region directly next to the propagation angle changing unit is d2, a distance from an end far from the illumination unit of the propagation angle changing unit to an end far from the illumination unit of the light extraction region directly next to the propagation angle changing unit is d3, an inclination angle of the inclined surface is c, and a propagation angle of the light is φ.