Backlight Light Guide Plate Positioning for Brightness Uniformity
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Solution Overview
Problem
Conventional liquid crystal display backlights suffer from non-uniform in-plane brightness and variations in brightness due to the relative position of the light source unit with respect to the light guide plate not being maintained at a fixed position, leading to light scattering and reduced brightness.
Innovation Solution
A backlight design that includes a rear frame with protrusions fitted into recesses on the light guide plate, along with a joining medium or intermediate frame to secure the light guide plate, ensuring a fixed position of the light source unit relative to the light guide plate, thereby reducing light scattering and enhancing uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the light source unit is positioned relative to the light guide plate without fixed positioning structures, then the device complexity is reduced and ease of manufacture is improved, but the uniformity of in-plane brightness deteriorates and brightness variations increase
Solution Approach 1:
The positioning structure is segmented into protrusions on the rear frame and corresponding recesses on the light guide plate. This segmentation allows for simple manufacturing of individual components while achieving precise relative positioning when assembled, thus resolving the contradiction between ease of manufacture and manufacturing precision.
Solution Approach 2:
The protrusions and recesses act as intermediary positioning elements between the rear frame and light guide plate. These intermediaries ensure fixed relative positioning without requiring complex direct coupling mechanisms, maintaining both ease of manufacture and brightness uniformity.
2Device complexity
If the light source unit is positioned relative to the light guide plate without fixed positioning structures, then the device complexity is reduced, but light scattering increases and brightness uniformity deteriorates
Solution Approach 1:
The positioning function is segmented into discrete protrusions and recesses rather than requiring a complex continuous positioning mechanism. This segmentation achieves effective light source positioning with minimal structure, reducing device complexity while preventing light scattering.
Solution Approach 2:
The protrusions and recesses are designed to automatically align and fix the relative position of the light source unit and light guide plate during assembly. This self-aligning mechanism eliminates the need for additional complex positioning devices, reducing device complexity while ensuring proper light guidance without scattering.
3Manufacturing precision
If protrusions and recesses are added to fix the relative position of the light source unit and light guide plate, then the uniformity of in-plane brightness is improved, but the device complexity increases
Solution Approach 1:
The positioning protrusions are integrated into the rear frame structure and the recesses are integrated into the light guide plate structure. This merging of positioning functions into existing components avoids adding separate complex positioning devices, thus improving brightness uniformity without significantly increasing device complexity.
Solution Approach 2:
The rear frame and light guide plate serve multiple functions: structural support, light guidance, and precise positioning. By making these components multi-functional, the patent avoids adding dedicated positioning mechanisms, thereby improving manufacturing precision without proportionally increasing device complexity.
4Ease of operation
If the relative position of the light source unit is not fixed, then the ease of assembly is improved, but brightness variations among individual backlights increase
Solution Approach 1:
The positioning system is segmented into standardized protrusions and recesses that provide repeatable positioning across multiple assemblies. This segmentation enables easy assembly through simple engagement while ensuring consistent relative positioning that prevents brightness variations among individual backlights.
Solution Approach 2:
The dimensions and geometries of the protrusions and recesses are carefully designed with specific parameters to ensure proper fit and fixed relative positioning. By optimizing these geometric parameters, the patent achieves both ease of assembly and reliable brightness consistency across production batches.
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 design improves the uniformity of in-plane brightness and reduces variations among individual backlights by maintaining the relative position of the light source unit, resulting in higher efficiency, brightness, and lower power consumption.
Implementation Method 1
The light guide plate guides incident light and emits the guided light from a main surface of the light guide plate
Data Source
AI summary
The rear frame includes a frame-like body and a protrusion. The protrusion projects from an inner surface of the frame-like body. A light source unit is disposed on the inner surface, and includes a point light source. The light incident surface on a side surface of the light guide plate faces a light-emitting surface with a gap. An abutting side surface of the light guide plate projects toward the inner surface. The protrusion is fitted to a recess on the abutting side surface. The joining medium joins the abutting side surface with the light source unit. Alternatively, a projecting portion of the light guide plate projects in a direction different from a direction in which the abutting side surface projects. The intermediate frame sandwiches the light guide plate together with the rear frame and includes a sandwiching portion. The sandwiching portion sandwiches the projecting portion.