Reflective Paper Coating to Prevent Backlight Edge Deformation

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Solution Overview

Problem

Existing direct backlight modules suffer from issues of collapsing or bulging edges in reflective films, affecting display quality.

Innovation Solution

A reflective film with a coating layer, such as a transparent or white curable adhesive, is applied to increase stiffness, and optionally combined with support structures, to stabilize the inclined parts of the reflective layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a reflective film is used in a direct backlight module, then light reflection efficiency is improved, but the edges of the reflective film collapse or bulge affecting display quality

Engineering Contradiction:
Improvelight reflection efficiencyVSAvoidedge flatness of reflective film
Core Design Contradiction:
Use of energy by moving objectVSManufacturing precision

Solution Approach 1:

The reflective film is constructed as a composite structure comprising a reflective layer and a coating layer. The coating layer (made of transparent curable adhesive or white curable adhesive) is applied to the rear side of the reflective layer to increase stiffness and prevent edge collapsing or bulging, while maintaining light reflection efficiency through high light transmittance or diffuse reflection properties.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The coating layer is selectively applied to specific regions of the reflective film, particularly the rear side and/or front side of the inclined part, rather than uniformly across the entire surface. This localized application provides targeted structural support to prevent edge deformation while preserving optical performance in critical areas.

Inventive Principle:
Principle #3Local quality

2Stability of the object's composition

If the stiffness of the reflective film is increased to prevent edge collapsing, then structural stability is improved, but material cost and device complexity increase

Engineering Contradiction:
Improvestructural stability of reflective filmVSAvoidcomplexity of reflective film structure
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The reflective film uses a composite structure with a reflective layer and a coating layer. The coating layer (transparent curable adhesive or white curable adhesive) provides enhanced stiffness and structural stability when cured, preventing edge collapsing or bulging without requiring complete structural redesign of the entire reflective film system.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The coating layer is applied locally to the rear side and/or front side of the inclined part of the reflective layer, providing targeted structural reinforcement only where needed to prevent edge deformation. This localized approach increases stiffness where required while minimizing additional material cost and structural complexity.

Inventive Principle:
Principle #3Local quality

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 effectively mitigates edge bulging and collapsing, ensuring even backlight emission and improved display quality by enhancing the mechanical stability of the reflective film.

Implementation Method 1

the coating layer is provided on the reflective layer to increase the stiffness of the reflective film (in other words, the stiffness of the reflective film provided with the coating layer is higher than stiffness of the reflective layer itself)

Methodology Applied
Scientific EffectStiffness enhancement through coating layer:

Implementation Method 2

because the transparent curable adhesive has a high light transmittance, even if the transparent curable adhesive is provided on the front side of the inclined part of the reflective layer, a normal function of the front sides of the reflective film is not affected

Methodology Applied
Scientific EffectLight reflection and transmittance: Reflection

Data Source

PatentEP4321927B1Reflective paper, backlight module and display device
Publication Date: 2025.10.29 HONOR DEVICE CO LTD
  • EP4321927B1 patent drawingFigure 1~2
  • EP4321927B1 patent drawingFigure 3~4
  • EP4321927B1 patent drawingFigure 5~6

AI summary

This application relates to the field of display technologies, to resolve a problem of collapsing or bulging of edges of reflective films in existing direct backlight modules, and provides a reflective film, a backlight module, and a display apparatus. The reflective film includes a reflective layer and a coating layer. The reflective layer includes a bottom and inclined parts extending around the bottom, folding lines are provided between the inclined parts and the bottom, and when the reflective film is folded along the folding lines, the inclined parts are inclined along peripheral edges of the bottom toward a side away from the bottom, and the bottom and the inclined parts together form an accommodating space. A plurality of through holes are provided at intervals in the bottom, and the inclined parts each include a front side facing the accommodating space and a rear side opposite to the front sides. The front sides are configured to reflect light. The coating layer is provided on the reflective layer to increase stiffness of the reflective film. The reflective film can effectively mitigate the problem of collapsing or bulging of the edges of the reflective film, to improve a display effect of the display apparatus using the reflective film.