Liquid Crystal Display Backlight Segmentation for Luminance Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In-vehicle liquid crystal display devices face challenges in achieving sufficient luminance in the main display direction while minimizing luminance in other directions, particularly in switching between wide and narrow view angle modes to prevent driver distraction.
Innovation Solution
A liquid crystal display device configuration featuring a first backlight, a transparent sidelight-type second backlight with a light guide plate and prism-like irregularities, and a transmissive liquid crystal panel with comb-like electrodes, allowing for adjustable luminance profiles by controlling the backlights and an optical device's state to manage light distribution and diffraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If both backlights are turned on for wide view angle mode, then luminance in main and sub display directions is sufficient, but luminance control in directions other than main display direction becomes difficult
Solution Approach 1:
The backlight system is segmented into two independent backlights: a first backlight for providing base luminance and a second transparent backlight for enhancing luminance in specific directions. This segmentation allows independent control of each backlight to achieve different luminance profiles for wide and narrow view angle modes, resolving the contradiction between sufficient luminance coverage and precise luminance control.
Solution Approach 2:
The system dynamically switches between different backlight configurations: in wide view angle mode, both backlights are turned on to provide sufficient luminance in main and sub display directions; in narrow view angle mode, only the first backlight is turned on while the second backlight is turned off, enabling precise luminance control in directions other than the main display direction.
2Object-affected harmful factors
If only first backlight is used for narrow view angle mode, then luminance in directions other than main display direction is reduced, but luminance in main display direction may be insufficient
Solution Approach 1:
The two backlights are merged into a unified illumination system where the first backlight provides controlled luminance for narrow view angle mode and the second transparent backlight enhances luminance when needed. By combining these light sources, the system achieves both reduced luminance in unwanted directions and sufficient luminance in the main display direction simultaneously.
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
Enables sufficient luminance in the main display direction and reduced luminance in other directions, effectively addressing the need for wide and narrow view angle modes to prevent driver distraction by optimizing light distribution and diffraction.
Implementation Method 1
Prism-like irregularities extending in a vertical direction are formed on a surface of the light guide plate on a side of the first backlight
Implementation Method 2
transparent sidelight-type second backlight including a transparent light guide plate disposed to face the first backlight
Implementation Method 3
transmissive liquid crystal panel in a horizontal electrical field mode
Implementation Method 4
electrode having a comb-like shape extending in a horizontal direction or an electrode having a slit extending in a horizontal direction is disposed in each pixel
Data Source
AI summary
A liquid crystal display device includes a narrow light distribution backlight, a transparent backlight disposed in front of the narrow light distribution backlight, and a transmissive liquid crystal panel in a horizontal electrical field mode. The transparent backlight is a sidelight type backlight including a transparent light guide plate disposed to face the narrow light distribution backlight and a light source disposed on a side surface of the light guide plate. Prism-like irregularities extending in a vertical direction are formed on a surface of the light guide plate on a side of the narrow light distribution backlight. An electrode having a comb-like shape extending in a horizontal direction is disposed in each pixel of the transmissive liquid crystal panel.