Light-emitting device insulating layer thickness for wide-angle chromaticity
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Solution Overview
Problem
Existing display devices, such as head-mounted displays, face challenges in maintaining chromaticity and visual field angle characteristics when the angle of view is increased, leading to noticeable color shifts at the peripheral edges due to changes in optical path length and phase conditions.
Innovation Solution
A light-emitting device with a configuration that includes a first sub-pixel and a second sub-pixel in a display region, featuring a reflective layer, a semi-transmissive reflective layer, and an optical resonance structure, where the insulating layer in the second sub-pixel is thicker than in the first sub-pixel, allowing for adjusted optical path lengths to maintain resonance conditions across different angles of view.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the angle of view is increased to achieve a large virtual image on a small display device, then the visual field angle is improved, but chromaticity shifts occur at peripheral edge portions due to changes in optical path length and phase condition
Solution Approach 1:
The patent applies local quality by making the insulating layer thickness position-dependent within the pixel. Specifically, the insulating layer has a first thickness in a first region (central area) and a second thickness in a second region (peripheral area), with the second thickness being greater than the first. This local variation compensates for the optical path length differences caused by tilted principal rays at peripheral regions, thereby maintaining chromaticity consistency across the entire display area even when the visual field angle is increased.
2Measurement precision
If the optical path length is optimized for vertical light emission, then the resonance wavelength is accurate for the central area, but the resonance wavelength shifts for tilted light emission at peripheral areas
Solution Approach 1:
The patent applies parameter changes by modifying the insulating layer thickness parameter to compensate for optical path length variations. The insulating layer thickness is increased in the second region compared to the first region, which changes the overall optical path length in the pixel. This parameter adjustment compensates for the additional optical path length introduced by tilted light emission at peripheral regions, thereby maintaining the phase condition for optical resonance and preventing resonance wavelength shifts across different viewing angles.
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 ensures consistent chromaticity and improved visual field angle characteristics by optimizing optical path lengths, even at larger angles of view, thereby enhancing the display's performance and reducing chromaticity changes.
Implementation Method 1
an optical resonance structure in which light radiated from the light-emitting functional layer resonates between the reflective layer and the semi-transmissive reflective layer
Implementation Method 2
the insulating layer in the second sub-pixel is thicker than the insulating layer in the first sub-pixel... a wavelength range of light emitted at a predetermined tilt angle from the second sub-pixel matches a wavelength range of light emitted in a vertical direction from the first sub-pixel
Data Source
AI summary
A light-emitting device includes a semi-transmissive reflection layer, a first reflection layer that is disposed in a first sub-pixel, a first pixel electrode that is disposed in the first sub-pixel, a first color filer that is disposed in the first sub-pixel, a second reflection layer that is disposed in a second sub-pixel, a second pixel electrode that is disposed in the second sub-pixel, a second color filter that is disposed in the second sub-pixel, the second color filter that is same color as the first color filter, a light-emitting functional layer, and an insulating layer that is disposed between the first reflection layer and the first pixel electrode, the light-emitting functional layer that is disposed between the second reflection layer and the second pixel electrode. A thickness of the insulating layer in the second sub-pixel is thicker than a thickness of the insulating layer in the first sub-pixel.