Backlight Unit Light Shielding Structure for Edge Leakage
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Solution Overview
Problem
In liquid crystal display devices, the edge light leakage phenomenon occurs due to projecting lugs on the light guide plate, leading to locally brightening or darkening issues, which affect the brightness and uniformity of the backlight unit.
Innovation Solution
A light shielding structure is provided on the light exit surface of the first protrusion portion of the light guide plate, partially covering the light exit surface to mitigate or eliminate the edge light leakage, comprising a first portion covering outer edges and a second portion covering the central region, with patterns that gradually decrease in size to optimize light distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If projecting lugs are provided on the light guide plate for fixation, then the light guide plate can be firmly fixed to the plastic frame, but edge light leakage occurs causing locally brightening or darkening
Solution Approach 1:
The harmful light leakage is extracted and blocked by introducing a light shielding structure specifically at the protrusion portion, separating the fixation function from the light emission function. The light shielding structure is applied only on the light exit surface of the protrusion portion, not on the entire light guide plate, thus blocking harmful light while preserving useful light emission areas.
Solution Approach 2:
The light shielding structure is applied locally only on the light exit surface of the protrusion portion rather than uniformly across the entire light guide plate. This local application allows the protrusion to maintain its fixation function while eliminating light leakage only where it occurs, preserving light emission in other areas.
2Object-generated harmful factors
If the light shielding structure completely covers the light exit surface of the protrusion portion, then light leakage is fully blocked, but locally darkening occurs
Solution Approach 1:
Instead of completely covering the light exit surface of the protrusion portion, the light shielding structure is applied partially. This partial coverage is sufficient to block the harmful edge light leakage while leaving enough uncovered area to prevent local darkening, maintaining overall brightness uniformity.
3Object-generated harmful factors
If a black plastic frame is used to reduce light leakage, then light leakage at protrusion positions is reduced, but overall light loss increases
Solution Approach 1:
The light shielding structure is applied locally only on the light exit surface of the protrusion portion rather than using a black plastic frame for the entire frame structure. This localized approach blocks light leakage only where needed while allowing the rest of the frame to remain transparent or translucent, preserving overall light transmission and reducing energy loss.
Solution Approach 2:
Instead of making the entire plastic frame black (which would cause continuous light loss), a thin light shielding layer is applied only where necessary. This minimal intervention approach uses less material and causes less light loss while achieving the same light leakage prevention effect.
Data Source
AI summary
A backlight unit, a display device, and a method for manufacturing a backlight unit are provided. The backlight unit includes a light guide plate including a main body and a first protrusion portion protruding from a side of the main body; a plastic frame provided at a periphery of the side of the light guide plate, wherein a side of the plastic frame proximal to the light guide plate has an engaging groove provided thereat, and the first protrusion portion of the light guide plate protrudes towards the plastic frame and is engaged in the engaging groove; and a light shielding structure provided on a light exit surface of the first protrusion portion, wherein an orthographic projection of the light shielding structure on the light exit surface of the first protrusion portion partially covers the light exit surface of the first protrusion portion.