Backlight Unit Diffusion Plate Extension for Light Leak Prevention
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Solution Overview
Problem
The light leak phenomenon occurs in liquid crystal displays due to gaps between the light guiding plate and the flexible printed circuit board, which affects the display quality and reduces the effectiveness of the backlight unit, especially in narrow-bezel displays where the distance between the light source and the visible area is minimized.
Innovation Solution
A backlight unit design that includes a diffusion plate with extension parts positioned between the circuit board and the light guiding plate, aligned with the light sources, to fill the gaps and prevent light leakage, and optionally uses a connecting layer with concave parts to secure the circuit board and light guiding plate while allowing the diffusion plate extensions to block light leaks effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If adhesive tape is used to bond the light guiding plate and the flexible printed circuit board, then the components can be assembled together, but gaps exist between the components and light leak phenomenon occurs
Solution Approach 1:
A light blocking layer is introduced as an intermediary component between the flexible printed circuit board and the light guiding plate. This layer specifically blocks light from leaking through the gap while allowing the adhesive tape to continue performing its bonding function. The light blocking layer acts as a mediator that resolves the conflict between easy assembly and light leak prevention.
Solution Approach 2:
The light blocking layer is segmented into multiple parts, including a first light blocking part extending from the flexible printed circuit board and a second light blocking part extending from the light guiding plate. These segmented parts work together to block light from different angles and ensure complete light leak prevention while maintaining assembly simplicity.
2Shape
If the distance between the light bar and the visible area is reduced for narrow-bezel display, then the display bezel becomes narrower, but light emitted by LEDs passes through the gap and enters the visible area causing light leak
Solution Approach 1:
The light blocking layer is positioned in advance to prevent light from reaching the visible area through the gap. By placing the light blocking layer between the light source and the potential leak path before light emission occurs, the design preemptively blocks the harmful light paths that would otherwise enter the visible area in narrow-bezel configurations.
Solution Approach 2:
The solution addresses the light leak problem by adding a new dimensional element (the light blocking layer extending into the gap space) rather than simply increasing the distance between components. This dimensional approach allows narrow bezel design while blocking light leaks through the gap.
3Ease of operation
If expansion gap is set aside during assembly of the flexible printed circuit board and diffusion plate, then the components can be assembled with proper clearance, but the gap allows light to pass through and cause light leak phenomenon
Solution Approach 1:
The light blocking layer serves as an intermediary that fills the expansion gap while maintaining the necessary assembly clearance. It allows the diffusion plate and flexible printed circuit board to be assembled with proper spacing for thermal expansion and manufacturing tolerances, while simultaneously blocking light from passing through this necessary gap.
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 eliminates light leaks and improves the display performance and production quality by ensuring that all light emitted by the sources is directed through the diffusion plate, reducing the firefly phenomenon and enhancing the overall display effect.
Implementation Method 1
a diffusion plate provided on the light exit side of the light guiding plate. The diffusion plate includes a diffusion-plate body and at least one diffusion-plate extension part
Data Source
AI summary
A backlight unit and a display device are provided. The backlight unit includes: a circuit board (20); at least one light source (21) provided on the circuit board (20); a light guiding plate (112) comprising a light incident side, which is configured for receiving light emitted by the at least one light source, and a light exit side; and a diffusion plate (114) provided on the light exit side of the light guiding plate (112). The diffusion plate (114) includes a diffusion-plate body (141) and at least one diffusion-plate extension part (142) that is located on at least one side of the diffusion-plate body (141) and connected to the diffusion-plate body (141). The diffusion-plate extension part (142) is located between the circuit board (20) and the light guiding plate (112). A position of the diffusion-plate extension part (142) corresponds to a position of the light source (121).