Cover-Mounted Light Guide for Accurate Display Illuminance Sensing
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Solution Overview
Problem
Existing display devices face challenges in accurately detecting illuminance and controlling luminance due to light reflection at interfaces between the cover, decorative layer, and light guide, which can impair design aesthetics and user experience.
Innovation Solution
A display device configuration that includes a cover with a light guide fixed via an adhesive layer, eliminating interfaces between the cover and air, and between the light guide and air, thereby reducing light reflection and enhancing illuminance detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a light guide is disposed to penetrate through the cover and decorative layer, then illuminance detection is enabled, but the decorative layer cannot be provided in the light guide area which impairs design aesthetics
Solution Approach 1:
A resin layer is introduced as an intermediary substance to fill the space between the cover and the light guide. This resin layer has a refractive index matched to both the cover and the light guide, creating optical continuity that makes the light guide invisible through the decorative layer while maintaining its functional presence for illuminance detection.
2Ease of operation
If there is air between the light guide and the cover, then the light guide can be positioned inside the display device, but light reflection occurs at the interfaces which reduces illuminance detection accuracy and makes the light guide visible
Solution Approach 1:
The resin layer serves as an intermediary that replaces air between the cover and the light guide. By eliminating the air interface, it prevents light reflection and refraction that would otherwise occur at the air-cover and air-light guide boundaries, thereby maintaining optical continuity and detection accuracy.
Solution Approach 2:
The resin layer is designed with a refractive index that is homogeneous with both the cover and the light guide materials. This refractive index matching creates optical homogeneity across the interface, eliminating visible boundaries and reducing light reflection, making the light guide invisible while maintaining positioning flexibility.
3Shape
If the light guide is fixed to the cover with an adhesive layer, then the interface between cover and air is eliminated, but the adhesive layer must have matched refractive index to maintain aesthetics
Solution Approach 1:
The adhesive layer is selected or formulated to have a refractive index that is homogeneous with the cover, decorative layer, and light guide. This refractive index matching ensures that the adhesive layer does not create visible interfaces or light reflection, maintaining the seamless aesthetic appearance while providing the necessary mechanical bonding function.
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 solution allows for more accurate detection of incident light illuminance, enabling proper control of display luminance and maintaining a seamless design aesthetic by minimizing the visibility of the light guide.
Implementation Method 1
a light guide that includes a first incidence end, which is an end fixed to the cover, the light guide guiding light incident on the first incidence end to the illuminance sensor
Implementation Method 2
an illuminance sensor that is located on the second surface side and that detects illuminance of incident light
Data Source
AI summary
In a display device, a display panel displays an image. A cover is located closer to a viewer than the display panel and having translucency. The cover has a first surface located on the viewer's side and a second surface located opposite to the first surface. A decorative layer covers at least one of the first surface or the second surface. An illuminance sensor is located on the second surface side and detects illuminance of incident light. A light guide includes a first incidence end, which is an end fixed to the cover, and guides light incident on the first incidence end to the illuminance sensor.