Backlight Unit Reflector Guide Pocket Thermal Deformation
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Solution Overview
Problem
LCD display apparatuses face issues with thermal deformation causing wrinkles in optical sheets and reflective sheets, leading to assembly failures and image quality deterioration, particularly during high-temperature reliability evaluations.
Innovation Solution
A backlight unit with a mold-type reflector structure that includes guide pockets and protrusions for aligning and securing the light guide plate and optical sheets, eliminating the need for conventional support structures and allowing for uniform light distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If optical sheets and reflective sheets are formed of thin sheet material to achieve thinness and flexibility, then the display apparatus can be made thinner and more flexible, but assembly failure occurs during assembly and wrinkles appear due to thermal deformation
Solution Approach 1:
The bottom cover is divided into a body portion and a projection that extends toward the light guide plate. The projection creates a distinct assembly region separated from the main body, allowing the thin optical sheets to be positioned and fixed in a dedicated space without direct contact with the main cover structure, thereby preventing assembly failures while maintaining thinness.
Solution Approach 2:
A fixation structure is introduced as an intermediary element between the thin optical sheets and the bottom cover. This fixation structure provides mechanical support and thermal isolation, preventing direct thermal transmission to the thin sheets while ensuring reliable assembly and preventing wrinkles during high-temperature operations.
2Ease of manufacture
If conventional support structures are used to fix the light guide plate, then assembly is straightforward, but the structure becomes complex and light uniformity is compromised
Solution Approach 1:
The bottom cover is merged with an integrated fixation structure that combines support and positioning functions. The projection extending from the bottom cover body creates fixation pockets that naturally hold the light guide plate in position, eliminating the need for separate support structures while maintaining assembly ease and improving light uniformity through better structural integration.
3Stability of the object's composition
If optical sheets are allowed to move freely to accommodate thermal expansion, then thermal stress is reduced, but image quality deteriorates due to wrinkles and misalignment
Solution Approach 1:
The bottom cover structure transitions from a uniform flat surface to a non-uniform structure with a projection creating a localized fixation region. This local structural variation provides precise positioning for the optical sheets in the assembly region while allowing other areas to accommodate thermal expansion, maintaining both alignment precision and thermal stability.
Solution Approach 2:
The projection structure is pre-formed in the bottom cover to create fixation pockets before assembly. These pockets preliminarily position the optical sheets and light guide plate in the correct alignment, ensuring manufacturing precision is maintained even when thermal expansion occurs during operation, as the structures are already constrained in their proper positions.
Data Source
AI summary
Discussed are a backlight unit and a display apparatus including the same. The display apparatus includes a light guide plate, optical sheets arranged on an upper surface of the light guide plate, a reflector configured to receive the light guide plate and the optical sheets therein, and a bottom cover configured to receive the reflector therein.