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

Abstract

A light-emitting device has a surface structure (13) of the surface of a transparent substrate (5). The surface structure is so configured that the surface of the transparent substrate (5) adjoining a light-emitting body is demarcated by multiple line segments having a width of approximate w inclined in a specific direction parallel to the surface, the line segments are divided in the length direction of the line segments by micro-regions such that the diameter of the largest one of the circles inscribing the micro-regions lies in the range from 0.2 [mu]m to 1.5 [mu]m, each of the micro-regions has a protruded or recessed shape on the surface of the transparent substrate (5), the proportions of the protrusions and recesses are P and 1-P respectively, and P lies in the range from 0.4 to 0.98.

Description

technical field [0001] The present invention relates to a transparent optical sheet, a light-emitting device, and a manufacturing method thereof, which are used so that one surface thereof adjoins a light-emitting body. Background technique [0002] As conventional techniques, there are techniques disclosed in Patent Documents 1 and 2, for example. [0003] figure 1 Shows the cross-sectional structure and propagation of light of a light-emitting device using a general organic electroluminescence element (organic EL element). On the substrate 101 , an electrode 102 , a light emitting layer 103 , and a transparent electrode 104 are stacked in this order, and a transparent substrate 105 is placed on the transparent electrode 104 . A voltage is applied between the electrode 102 and the transparent electrode 104, and the point S inside the light-emitting layer 103 emits light. The light passes through the electrode 104 directly or after being reflected by the electrode 102, and...

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Problems solved by technology

[0021] In addition, in the technology disclosed in Patent Document 1, although it is possible to extract light that will become total reflection with certainty, the opposite also exists.

That is, when it is assumed that there is no diffraction grating layer, the light emitted from a point in the light-emitting layer may be incident at an angle smaller than the critical angle on the refracting surface (exiting surface) of the transparent substrate and be transmitted and refracted. When there is a diffraction grating layer and diffraction occurs due to this, the incident angle on the refracting surface exceeds the critical angle and total reflection occurs.

Therefore, the technology disclosed in Patent Document 1 cannot guarantee improvement in light extraction efficiency.

In addition, in the technique disclosed in Patent Document 1, diffracted light in which all light rays uniformly move in a predetermined direction occurs.

Light including such diffracted light has a distribution of light intensity due to azimuth, and since a predetermined amount of movement depends on the wavelength of outgoing light, there is an imbalance of color due to azimuth.

[0022] In addition, in the light-emitting device disclosed in Patent Document 1, light incident from the outside (air layer side) is regularly reflected by the surface of the transparent substrate, and constitutes interference (so-called reflection) with respect to light extracted from the light-emitting layer. Optical treatment such as an anti-reflection film is required on the surface of the transparent substrate, which increases the cost of the product

[0023] On the other hand, the purpose of the light-emitting device disclosed in Patent Document 2 is to prevent the reflection of light on the refracting surface, and the improvement in light extraction efficiency brought about by this structure is very small, only about 10 to 20 percent.

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