Micro Light-Emitting Pixel Optics for High Luminance at Small Pitch
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Solution Overview
Problem
Existing light-emitting devices with self-luminous micro elements face challenges in achieving high luminance while maintaining a compact form and reducing pixel pitch, as the isotropic scattering of light makes it difficult for the condenser section to effectively collect light.
Innovation Solution
Incorporating a light-emitting element with a light-reflective section, a lens, and a light-shielding section, where the light-shielding section has an opening to admit light, allowing the light to be reflected and collected efficiently, thereby improving luminance in the light exit direction without increasing pixel pitch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a self-luminous device is used as the micro light-emitting element with isotropic light scattering, then the device structure is simple, but the condenser section cannot sufficiently collect light into the light exit direction, resulting in low luminance
Solution Approach 1:
The light control section is divided into multiple functional sections: a light-reflective section that reflects isotropically scattered light, a light-shielding section with an opening to block unwanted light, and a lens section to collect and condense light. This segmentation allows each section to perform its specific function efficiently, resolving the contradiction between simple structure and high luminance by creating a multi-component system where each component is optimized for its role.
Solution Approach 2:
Different sections of the light control section have different optical properties tailored to their functions: the light-reflective section has high reflectivity, the light-shielding section has high absorption/blocking capability with a specific opening geometry, and the lens section has specific refraction properties. This local differentiation of optical qualities enables efficient light collection and direction control, achieving high luminance while maintaining reasonable structural complexity.
2Illumination intensity
If the diameter of the condenser section is increased to collect more light, then luminance in the light exit direction improves, but the pixel pitch increases, reducing display resolution
Solution Approach 1:
The light-reflective section performs preliminary action by reflecting isotropically scattered light toward the lens section before the light reaches the condenser. This preliminary redirection of light paths allows the lens to collect light more efficiently from a wider angular range, achieving high luminance without requiring an increased lens diameter, thus maintaining small pixel pitch.
Solution Approach 2:
The light-shielding section with its opening introduces a vertical dimension control to the optical path, blocking light from certain angles while allowing light from the desired direction to pass through. This dimensional control enables efficient light collection in the vertical direction without increasing the horizontal diameter of the lens, thereby maintaining small pixel pitch while achieving high luminance.
3Illumination intensity
If the light exit area of the wavelength conversion section is reduced to increase luminance, then luminance in the light exit direction improves, but the light collection area is reduced, making light collection more difficult
Solution Approach 1:
The light control section creates an asymmetric light path where light from a small light exit area is reflected and redirected multiple times to maximize collection efficiency. The light-reflective section and light-shielding section work together to create an asymmetric optical configuration that concentrates light from the small exit area into the lens, achieving high luminance without requiring a large light exit area.
4Illumination intensity
If multiple light control sections are added to improve light collection efficiency, then luminance improves, but the device height increases, resulting in a bulky structure
Solution Approach 1:
The light control section components are arranged in a nested configuration where the light-reflective section, light-shielding section with opening, and lens section are positioned concentrically around the light-emitting element. This nesting allows multiple light control functions to be packed into a compact vertical space, improving light collection efficiency while minimizing the overall device height and maintaining a low-profile structure.
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
This configuration enhances luminance in the light exit direction while allowing for a reduction in pixel pitch, enabling more efficient light collection and improved optical path length, which also helps in suppressing color mixing and maintaining a low-profile structure.
Implementation Method 1
a light-reflective section that reflects light emitted from the light-emitting surface
Implementation Method 2
a lens that collects the light emitted from the light-emitting surface
Data Source
AI summary
Alight-emitting device (1) includes a light-emitting element (2), a light-reflective section (3), a lens (5), and a light-shielding section (6). The light-emitting element (2) has a light-emitting surface (2A). The light-reflective section (3) reflects light emitted from the light-emitting surface (2A). The light-reflective section (3) is provided on an opposite side from the light-emitting surface (2A) of the light-emitting element (2) and a side-surface side of the light-emitting element (2). The lens (5) collects the light emitted from the light-emitting surface (2A). The lens (5) is provided on the light-emitting surface (2A) side. The light-shielding section (6) blocks the light emitted from the light-emitting surface (2A). The light-shielding section (6) is provided between the light-emitting surface (2A) and the lens (5) and has an opening (6A) to admit light. The opening (6A) penetrates the light-shielding section (6) in a thickness direction.