Mirror Display Using Multiple Reflective Polarizers
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Solution Overview
Problem
Conventional half mirror plates in mirror displays face challenges in achieving sufficient reflectance in mirror mode without compromising screen luminance in display mode, and they often incur high production costs due to complex configurations and limited production efficiency.
Innovation Solution
A mirror display configuration utilizing multiple reflective polarizers with intersecting transmission axes, where at least two half mirror layers include a reflective polarizer with its transmission axis parallel or perpendicular to the polarizer in the display device, ensuring a sum of transmittance in the display mode and reflectance in the mirror mode of 100% or higher, while maintaining efficient production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single reflective polarizer is used as a half mirror layer, then the structure is simple, but the reflectance in mirror mode is limited to about 50% which is insufficient
Solution Approach 1:
The patent divides the half mirror layer into multiple reflective polarizer layers (first reflective polarizer layer and second reflective polarizer layer) with different transmission axis orientations. This segmentation allows each layer to contribute differently to the overall reflectance, achieving sufficient mirror mode reflectance while maintaining reasonable structural complexity.
Solution Approach 2:
The patent uses a composite structure combining multiple reflective polarizer layers with different orientations and a retarder layer. This composite material approach enables the system to achieve both high reflectance in mirror mode and adequate transmittance in display mode, resolving the contradiction between simplicity and performance.
2Reliability
If a vapor-deposited metal film is used as a half mirror layer, then the reflectance can be increased, but the screen luminance in display mode decreases because only part of incident light is transmitted
Solution Approach 1:
The patent changes the optical parameters by using multiple reflective polarizer layers with specific transmission axis orientations (parallel and perpendicular) combined with a retarder layer. This parameter configuration allows the system to achieve high reflectance in mirror mode while maintaining high transmittance in display mode, avoiding the luminance loss associated with metal films.
Solution Approach 2:
The patent employs a composite structure of multiple reflective polarizer layers and a retarder layer that works together to control light polarization and reflection. This composite approach enables simultaneous optimization of reflectance and transmittance, overcoming the limitation of vapor-deposited metal films.
3Reliability
If multiple reflective polarizers with intersecting transmission axes are used to increase reflectance, then the reflectance in mirror mode increases significantly, but the production efficiency decreases due to complex configuration
Solution Approach 1:
The patent segments the reflective polarizer system into distinct first and second reflective polarizer layers with specific transmission axis orientations (parallel and perpendicular). This segmentation allows for standardized manufacturing of each layer independently, improving production efficiency while achieving high reflectance through the combined effect.
Solution Approach 2:
The patent optimizes the transmission axis orientations of the reflective polarizers (parallel and perpendicular arrangements) to achieve high reflectance with a manageable configuration. This parameter optimization balances performance requirements with manufacturing feasibility, avoiding excessive complexity.
4Reliability
If the transmission axis of reflective polarizers is oriented at specific angles to maximize reflectance, then the mirror function is enhanced, but the area yield decreases requiring larger polarizer areas
Solution Approach 1:
The patent divides the polarizer system into multiple layers with different transmission axis orientations. This segmentation allows the transmission axes to be oriented at specific angles (parallel and perpendicular) to maximize reflectance while maintaining compact overall dimensions, avoiding the need for excessively large polarizer areas.
Solution Approach 2:
The patent uses a composite structure of multiple reflective polarizer layers and a retarder layer that achieves high mirror function through their combined optical effects. This composite approach maximizes reflectance efficiency, reducing the required area compared to single-layer designs.
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 prevents a decrease in screen luminance during display mode while significantly increasing reflectance in mirror mode, offering excellent production efficiency and practical usability as both a display and a mirror.
Implementation Method 1
at least two half mirror layers include a reflective polarizer with its transmission axis parallel or perpendicular to the polarizer in the display device
Implementation Method 2
the mirror display utilizes the display light to show an image in a region where the display light is emitted from the display device. When no display light is emitted from the display device, on the other hand, the mirror display reflects the outside light
Data Source
AI summary
The present invention provides a mirror display that sufficiently prevents a decrease in the screen luminance in the display mode while sufficiently increasing the reflectance in the mirror mode, and also gives excellent production efficiency. The mirror display includes a half mirror plate including at least two half mirror layers; and a display device arranged on the backside of the half mirror plate, the display device including a polarizer, the at least two half mirror layers including at least one reflective polarizer, the transmission axis of the polarizer and the transmission axis of the at least one reflective polarizer being substantially parallel to each other or substantially perpendicular to each other, the mirror display configured to switch a display mode allowing display light to be emitted from the display device and to pass through the half mirror plate and a mirror mode preventing display light from being emitted from the display device, the mirror display exhibiting a sum of the transmittance in the display mode and the reflectance in the mirror mode of 100% or higher.