Inclined Liquid Crystal Panel Light Guide with Asymmetric Wedge
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Solution Overview
Problem
In image forming apparatuses using liquid crystal panels, variations in luminance occur when the panel is inclined relative to the substrate, and existing solutions with wedge-shaped light guide members fail to effectively suppress these variations.
Innovation Solution
A display device configuration featuring a light guide member with a convex emission surface inclined relative to the substrate, spaced from the liquid crystal panel, and light diffusion portions to reduce distance differences and suppress luminance variations, allowing the liquid crystal panel to be inclined while maintaining uniform illumination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the liquid crystal panel is arranged to be inclined relative to the substrate, then the display device can achieve a thinner profile and improved design flexibility, but variations in luminance occur due to different distances from the light source to the upper and lower parts of the panel
Solution Approach 1:
The light guide member employs an asymmetric wedge-shaped structure where the thickness varies along the length. The first end has a smaller thickness than the second end, creating an inclined emission surface that compensates for the inclination of the liquid crystal panel. This asymmetric design ensures that light is emitted at optimized distances to both the upper and lower parts of the inclined panel, maintaining uniform luminance distribution.
Solution Approach 2:
The patent changes the geometric parameters of the light guide member by introducing a wedge shape with specific thickness variations. The thickness parameter is deliberately modified along the length of the light guide member, transitioning from a uniform thickness to a gradient thickness profile. This parameter change allows the emission surface to be inclined at an angle that matches the panel inclination, thereby maintaining constant optical path length and uniform luminance.
2Illumination intensity
If a wedge-shaped light guide member is used to compensate for panel inclination, then some luminance variation can be addressed, but the light diffusion portions create visible unevenness that degrades appearance
Solution Approach 1:
The patent extracts the light diffusion function from the main body of the light guide member by adding separate light diffusion portions on the emission surface. These diffusion portions are distinct elements that can be independently optimized. By separating the light guiding function (wedge-shaped body) from the light diffusion function (surface portions), the design achieves both uniform luminance and smooth appearance without visible unevenness.
Solution Approach 2:
The light diffusion portions are strategically placed only in specific local regions on the emission surface where light diffusion is needed, rather than making the entire surface diffusive. This local application of diffusion properties allows the majority of the emission surface to maintain a smooth, uniform appearance while still achieving the necessary light distribution uniformity in the critical viewing areas.
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
This configuration reduces luminance variations, improves the appearance of the display by minimizing the visual impact of light diffusion portions, and facilitates easier adjustment of the light guide member's inclination, while maintaining a constant thickness and reducing the mounting area.
Implementation Method 1
emission light from a light source (i.e., backlight) provided on a substrate is guided to the liquid crystal panel by a light guide member
Implementation Method 2
The light guide member (32) has convex light diffusion portions (32D) arranged on the emission surface (32B)
Data Source
AI summary
A display device includes a light guide member, a light source substrate and a liquid crystal panel. The light guide member has a first incidence surface, and an emission surface orthogonal to the first incidence surface. The light source substrate has a light source emitting light toward the first incidence surface, and a substrate on which the light source is arranged. The liquid crystal panel has a second incidence surface arranged to be inclined relative to a surface of the substrate in a position where the liquid crystal panel faces the emission surface of the light guide member. A second angle between the emission surface and the surface of the substrate is greater than 0°, and is equal to or smaller than a first angle between the second incidence surface and the surface of the substrate.