Microlens Array for Display Device Vignetting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Self-luminous display devices, such as those using organic EL elements, face issues with reduced luminance and color shift due to light-shielding effects from black matrix layers, especially when viewed at oblique angles, and suffer from uneven aging across different color pixels, leading to degraded display quality and short service life.
Innovation Solution
The design involves a pair of substrates with self-luminous photo-emission elements and a black matrix layer, where specific dimensional relationships and current density adjustments are implemented to minimize vignetting and color shift, ensuring consistent aging across red, green, and blue pixels, thereby improving viewing angle characteristics and extending panel service life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a black matrix layer is provided to suppress reflection and improve contrast, then high contrast and color purity are achieved, but light-shielding occurs at oblique angles causing luminance reduction and vignetting
Solution Approach 1:
The patent transitions from a 2D planar black matrix layer to a 3D microlens array structure that protrudes from the substrate. This dimensional change allows the microlenses to focus and guide light at various angles, preventing vignetting while maintaining the black matrix's light-shielding function. The microlenses create a three-dimensional optical path that resolves the contradiction between contrast enhancement and luminance maintenance.
Solution Approach 2:
The microlens array acts as an intermediary between the organic EL element and the black matrix layer. These microlenses collect and redirect light that would otherwise be blocked by the black matrix at oblique angles, mediating between the conflicting requirements of high contrast (from the black matrix) and high luminance (preserved by the microlenses).
2Manufacturing precision
If the photo-emission section is limited to pixel pitch size, then pixel definition is maintained, but shadowed portions are generated by the black matrix layer at oblique viewing angles
Solution Approach 1:
By adding the vertical dimension with protruding microlenses, the patent extends the light-emitting effective area beyond the planar pixel pitch limitation. The microlenses capture light from the centered photo-emission section and redirect it to cover the full pixel area, eliminating shadowed portions while preserving sharp pixel boundaries.
Solution Approach 2:
The microlenses are pre-formed on the substrate before or during the assembly process, creating a predetermined light-guiding structure. This preliminary action ensures that light is properly directed from the photo-emission section to the pixel area, preventing shadowed portions from forming in the first place rather than correcting them afterward.
3Reliability
If aperture ratio is adjusted to compensate for aging differences among color pixels, then uniform aging is achieved, but vignetting and color shift occur at oblique angles
Solution Approach 1:
The patent implements different aperture ratios for different color pixels (R, G, B) to compensate for their different aging characteristics. Each color sub-pixel has locally optimized parameters: red pixels with larger apertures, green with medium, and blue with smaller apertures. This local quality adjustment achieves uniform aging across all colors while the microlens array ensures uniform light distribution at all viewing angles.
Solution Approach 2:
The patent changes multiple parameters simultaneously: aperture ratio, microlens diameter, and microlens height. By adjusting these parameters in combination, the system achieves both uniform aging compensation and uniform light distribution, resolving the contradiction between aging uniformity and vignetting prevention.
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 effectively suppresses vignetting and color shift within a 0° to 60° viewing angle range, maintaining balanced luminance and delaying color degradation, thus enhancing display quality and service life of the panel.
Implementation Method 1
a self-luminous photo-emission element such as an organic EL (electroluminescence) element
Implementation Method 2
a microlens having a lens optical axis and a lens top surface, the microlens having a positive power with respect to the lens optical axis
Data Source
AI summary
The present invention provides a display device including: a pair of substrates in which a plurality of pixels are disposed in a matrix form as a whole, the pixels being configured with pixels corresponding to R (red), G (green), or B (blue), and the pixels corresponding to the R, G, or B having size different from each other; a self-luminous photo-emission element formed in a region corresponding to each of the pixels, on one of the pair of substrates; and a black matrix layer formed in a region corresponding to among the pixels, on the other of the pair of substrates. Formula (1) and formula (2) are satisfied, or formula (1) and formula (3) are satisfied.