Asymmetric Backlight Module for Automotive Window Reflection Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional backlight modules for automotive displays face challenges in achieving the required wide viewing angle without causing light reflection from car windows, particularly in front-seat displays like the Driver Information Display (DID) and Co-Driver Display (CDD).
Innovation Solution
A backlight module comprising a surface light source, optical film, and light control film with asymmetrical optical structures that deflect light to one side, using a combination of optical films and light control films to suppress light emission on the other side, reducing reflections from side windows.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional backlight modules use wide viewing angle light distribution, then passengers on both left and right sides can see the displayed content, but light is reflected by car windows and affects the driver
Solution Approach 1:
The patent applies asymmetry by designing the light control film with asymmetric optical structures (prisms with different angles on each side) that deflect light differently in left and right directions. The first prism structure has a first deflection angle for light toward the driver side, while the second prism structure has a second deflection angle for light toward the passenger side, creating asymmetric light distribution that prevents window reflection while maintaining viewing angle
Solution Approach 2:
The patent implements local quality by making different regions of the light control film have different optical properties. The light control film includes a first region with first prism structures oriented to deflect light away from the driver side windows, and a second region with second prism structures oriented to deflect light away from the passenger side windows, allowing each region to locally control light direction according to its position
2Object-affected harmful factors
If light is deflected to one side to prevent window reflection, then driver visibility is improved, but light distribution becomes asymmetrical requiring complex optical structures
Solution Approach 1:
The patent merges the light control film with the optical film into a single integrated component. The light control film is positioned between the optical film and the display panel, combining light deflection and viewing angle control functions in one element, which simplifies the overall structure compared to using separate components
Solution Approach 2:
The light control film acts as an intermediary between the optical film and the display panel. It receives light from the optical film and redirects it asymmetrically to prevent window reflection, serving as a mediating layer that solves the reflection problem without requiring fundamental changes to the existing backlight module structure
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 directs light to one side, minimizing reflections from side windows and ensuring clear visibility in front-seat displays by controlling light distribution asymmetry.
Implementation Method 1
the light emitted by the surface light source has an angular range of δ relative to the normal direction of the backlight module when passing through the optical film
Implementation Method 2
the light deflects in the direction away from the first optical surface after entering the light control film
Implementation Method 3
the light emission angle δ of the optical film, the first included angle θ1 of the light control film, and the critical angle θc of the light control film satisfy the following relationship: δ+θ1<θc
Data Source
AI summary
A backlight module includes a light source, an optical film, and a light control film. The light control film has a first reference surface and a plurality of first optical structures disposed on the first reference surface. Each of the first optical structures has a first optical surface and a second optical surface. A first included angle is formed between the first optical surface and the first reference surface. A second included angle is formed between the second optical surface and the first reference surface. The first included angle is an acute angle and is smaller than the second included angle. Thereby, the light can be deflected to one side and the light output of the other side can be suppressed. This invention also provides a display device including the backlight module.