Backlight Device with Integrated Phosphor and Wavelength Selective Layer
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Solution Overview
Problem
Liquid crystal display apparatuses with remote phosphor configurations face limitations in reducing thickness and improving mass productivity, particularly due to the thickness of the backlight device and issues with color non-uniformity during partial drive methods.
Innovation Solution
A liquid crystal display apparatus with a backlight device that includes an LED substrate, a phosphor layer, a wavelength-selective reflection layer, and an optical layer stack secured to the back surface of the liquid crystal display panel via adhesive layers, where the optical layer stack and phosphor layer are bonded with a first adhesive layer forming an air layer, enhancing light efficiency and reducing thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a remote phosphor configuration is used to improve color uniformity, then color non-uniformity is suppressed, but the thickness of the backlight device increases
Solution Approach 1:
The patent merges the optical layer stack and phosphor layer into a single integrated component that is bonded directly to the liquid crystal display panel. This integration eliminates the need for a separate remote phosphor module, thereby maintaining color uniformity benefits while reducing overall backlight device thickness.
Solution Approach 2:
The patent implements a nested structure where the optical layer stack is positioned within the same space as the phosphor layer, with both layers bonded to the panel back surface. This nesting arrangement allows the excitation light to pass through the optical layer stack and reach the phosphor layer, achieving both thinness and color uniformity.
2Length of stationary object
If the optical layer stack and phosphor layer are bonded directly to reduce thickness, then thickness is reduced, but light efficiency and color uniformity deteriorate
Solution Approach 1:
The patent applies local quality by creating discrete adhesive portions rather than a continuous adhesive layer. This allows different regions of the optical layer stack and phosphor layer to have different optical properties, enabling excitation light to pass through certain areas to reach the phosphor while maintaining structural bonding, thus preserving light efficiency despite direct bonding.
Solution Approach 2:
The adhesive layer is segmented into multiple discrete adhesive portions arranged in a matrix pattern. This segmentation allows excitation light to pass through the gaps between adhesive portions and reach the phosphor layer, maintaining light efficiency while achieving direct bonding for thickness reduction.
3Use of energy by moving object
If discrete adhesive portions are used to form air layers, then light efficiency is improved, but manufacturing complexity increases
Solution Approach 1:
The patent employs a simple matrix arrangement of discrete adhesive portions that can be easily manufactured using conventional techniques. The adhesive portions are arranged in regular intervals with simple geometric shapes, making the structure easy to manufacture despite the discrete nature, thereby achieving light efficiency without excessive manufacturing complexity.
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 improves brightness and reduces thickness and color non-uniformity, enabling better mass productivity and performance of liquid crystal display apparatuses by optimizing the use of excitation light and suppressing unwanted light reflections.
Implementation Method 1
a phosphor layer including a phosphor that receives the excitation light to emit luminescence
Implementation Method 2
a wavelength-selective reflection layer that is arranged between the phosphor layer and the LED substrate, wherein a transmittance for the excitation light is higher than a transmittance for the luminescence
Implementation Method 3
the first adhesive layer includes a plurality of adhesive portions arranged discretely and forms an air layer between the optical layer stack and the phosphor layer
Data Source
AI summary
A liquid crystal display device (100) according to the present invention is provided with a liquid crystal display panel (10) and a backlight device (50) which emits light toward the back surface (10r) of the liquid crystal display panel. The backlight device comprises: an LED substrate (21) that has a front surface (21s) on which a plurality of LED chips (22) are arranged so as to emit excitation light toward the back surface of the liquid crystal display panel; a phosphor layer (25) which contains a phosphor (25q) that emits fluorescent light upon reception of the excitation light; a wavelength selective reflection layer (28) which is arranged between the phosphor layer and the LED substrate, and wherein the transmittance of the excitation light is higher than the transmittance of the fluorescent light; and an optical layer laminate (30) which is arranged on the liquid crystal display panel side of the phosphor layer. The optical layer laminate, the phosphor layer and the wavelength selective reflection layer are affixed to the back surface of the liquid crystal display panel in an integrated manner, with a plurality of adhesive layers including a first adhesive layer (40a) being interposed therebetween.