Light Source Substrate Step Alignment for LCD Illumination Uniformity
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Solution Overview
Problem
Illumination unevenness occurs in liquid-crystal display apparatuses due to differences in reflectance and diffusion at the ends of light-guiding plates and light source substrates, which are not properly aligned, leading to inconsistent light distribution.
Innovation Solution
A configuration where a light-guiding plate and a light source substrate are supported by a base plate portion of a frame, with a step portion allowing precise positioning of the light source substrate and a light-guiding plate support portion, substrate support portion, and step portion formed in the frame to maintain proper attitude and alignment, ensuring uniform light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the light-guiding plate and light source substrate are supported by a base plate portion with recessed substrate support portion, then the light-emitting elements can be mounted on the light source substrate, but illumination unevenness occurs at the ends of the light-guiding plate due to overlapping areas with different reflectance and diffusion properties
Solution Approach 1:
The base plate portion is segmented into distinct functional zones: a light-guiding plate support portion at a first level, a substrate support portion at a second (lower) level, and a step portion connecting them. This segmentation allows each zone to perform its specific function independently, preventing illumination unevenness while maintaining structural organization.
Solution Approach 2:
The invention introduces a vertical dimension (height difference) between the light-guiding plate support portion and substrate support portion. By positioning these support portions at different levels and connecting them via a step portion, the design creates a three-dimensional structure that resolves the two-dimensional overlap problem, ensuring uniform illumination without requiring complex planar arrangements.
2Use of energy by moving object
If a reflective sheet is provided on the rear surface of the light-guiding plate to improve light reflection, then light utilization is enhanced, but the reflective sheet warps due to height differences between contact portions and overlapping gaps, causing illumination unevenness
Solution Approach 1:
The step portion is designed beforehand to accommodate and compensate for the height differences that would otherwise cause reflective sheet warping. By providing this predetermined structural feature, the invention prevents the warping problem before it occurs, maintaining reflective sheet flatness while preserving efficient light reflection.
Solution Approach 2:
The step portion acts as an intermediary structure between the light-guiding plate support portion and the substrate support portion. It mediates the height difference issue, providing a transition that allows the reflective sheet to maintain contact with the light-guiding plate rear surface without warping, thus preserving both light reflection efficiency and sheet stability.
3Length of moving object
If the light source substrate is positioned closer to the light-guiding plate to reduce the apparatus thickness, then the overall device size is reduced, but precise alignment becomes difficult to maintain, leading to illumination unevenness
Solution Approach 1:
The substrate support portion is preliminarily positioned at a specific height below the light-guiding plate support portion, with the step portion pre-formed to receive the light source substrate. This preliminary positioning ensures that when the substrate is mounted, it automatically achieves the correct position and orientation, maintaining precise alignment even in a compact configuration.
Solution Approach 2:
The invention replaces complex mechanical alignment mechanisms with a simplified height-based positioning system. By using the step portion to establish a fixed height relationship between the light-guiding plate and light source substrate, precise alignment is achieved through vertical positioning rather than complex lateral adjustment mechanisms, enabling compact design without sacrificing positioning accuracy.
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 prevents illumination unevenness by ensuring precise alignment and consistent light distribution across the light-guiding plate, preventing warping of reflective sheets and maintaining optimal light-emitting element positioning, resulting in a thinner and more efficient illumination apparatus.
Implementation Method 1
a light-guiding plate 80 serving as a light entry portion 80a
Implementation Method 2
areas where the first frame 40 overlaps with a rear surface 80c of the light-guiding plate 80 and areas where the light source substrate 88 overlaps with the rear surface 80c of the light-guiding plate 80; at these areas, the reflectance, degree of diffusion, and so on of the light differs
Implementation Method 3
a plurality of light-emitting elements 89 disposed along a side-end surface of the light-guiding plate 80 that serves as a light-entry portion 80a
Implementation Method 4
although there are cases where a reflective sheet 187 is provided on the rear surface 80c of the light-guiding plate 80
Data Source
AI summary
An illumination apparatus includes: a light-guiding plate; a plurality of light-emitting elements disposed along a side-end surface of the light-guiding plate that serves as a light-entry portion, each of the plurality of light-emitting elements has a light-emitting surface which faces toward the light entry portion; a light source substrate, disposed and separated with a space from the light entry portion of the light-guiding plate when viewed from above, that includes a mounting surface for the plurality of light-emitting elements, the mounting surface being orthogonal to the side-end surface serving as the light entry portion; and a step portion with which an end portion of the light source substrate located toward the light-guiding plate makes contact.