Optical Sheet Wedge Layers Refraction Emission Angle Control
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Solution Overview
Problem
Conventional optical sheets used in display apparatuses suffer from luminance loss due to the absorption of light at emission angles greater than the cut-off angle, which limits their effectiveness in maintaining high luminance while controlling light emission.
Innovation Solution
An optical sheet comprising a first wedge layer with a specific refractive index and a wedge-shaped prism pattern, a second wedge layer with a higher refractive index, and a light blocking pattern disposed between them, which adjusts the emission angle and blocks light above the cut-off angle, thereby maintaining high luminance and controlling light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a louver structure with high aspect ratio is used to limit emission angle, then the viewing angle is controlled effectively, but luminance is lost due to light absorption
Solution Approach 1:
The optical sheet is divided into multiple functional layers: a first wedge layer with lower refractive index, a light blocking layer, and a second wedge layer with higher refractive index. Each layer serves a specific function in controlling light emission angles while minimizing luminance loss through the combination of refraction and selective blocking.
Solution Approach 2:
The invention changes the refractive index parameter by using materials with different refractive indices for the first and second wedge layers. This parameter difference enables effective light emission angle control through refraction at the interfaces, replacing the need for high aspect ratio louver structures that cause luminance loss.
2Ease of operation
If light blocking is implemented to control emission angle, then viewing angle is limited, but luminance loss occurs due to absorption
Solution Approach 1:
The light blocking layer is positioned specifically between the first and second wedge layers, blocking light only in specific directions where emission angle control is needed. This localized blocking approach minimizes overall luminance loss by allowing light to pass through in desired viewing directions while blocking only the unnecessary emission angles.
Solution Approach 2:
The optical sheet uses a composite structure combining materials with different optical properties: the first wedge layer material, the light blocking layer material, and the second wedge layer material with higher refractive index. This composite approach enables simultaneous achievement of emission angle control and luminance preservation through coordinated refraction and blocking effects.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The optical sheet effectively limits light emission at or above the cut-off angle, ensuring high luminance and preventing luminance loss while allowing for controlled light emission, thus enhancing the display apparatus's performance.
Implementation Method 1
a first wedge layer having a first refractive index and including a wedge-shaped prism pattern... a second wedge layer disposed on the first wedge layer and having a second refractive index greater than the first refractive index
Implementation Method 2
A conventional optical sheet may limit an emission angle by absorbing light having an emission angle equal to or more than a cut-off angle
Data Source
AI summary
An optical sheet includes a first wedge layer having a first refractive index and including a wedge-shaped prism pattern including an inclined surface having an inclination angle with respect to a plane defined by a first direction and a second direction perpendicular to the first direction and a vertical surface extending in a third direction perpendicular to the first direction and the second direction, a second wedge layer disposed on the first wedge layer and having a second refractive index greater than the first refractive index, and a light blocking pattern disposed between the first wedge layer and the second wedge layer and including a first surface that contacts with the vertical surface and a second surface inclined to have the inclination angle with respect to the plane while contacting with the inclined surface.