Backlight Device with Tilted Top-Emitting LEDs
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Solution Overview
Problem
Conventional side-lighting type backlight devices using side-emitting LEDs suffer from lower brightness and shorter life, while top-emitting LEDs, though brighter and longer-lasting, are difficult to adjust for uniform illumination in side-lighting configurations.
Innovation Solution
A side-lighting type backlight device employing top-emitting LEDs with tilting portions to adjust their illumination direction, ensuring efficient light distribution across the light guide plate, thereby enhancing brightness and uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If side-emitting LEDs are used in side-lighting type backlight devices, then the illumination direction can be easily adjusted to face the light incident surface, but the brightness and service life are reduced
Solution Approach 1:
The patent inverts the conventional approach by using top-emitting LEDs (which normally emit light perpendicular to the mounting surface) in a side-lighting configuration. By tilting the LEDs at specific angles (45-60 degrees), the light emission direction is redirected to face the side light incident surface, achieving both high brightness and proper illumination direction.
Solution Approach 2:
The patent changes the emission angle parameter of the LEDs by tilting them at specific angles (45-60 degrees) relative to the normal of the mounting surface. This parameter change allows top-emitting LEDs to redirect their light output toward the side light incident surface, resolving the contradiction between brightness and illumination direction adjustment.
2Illumination intensity
If top-emitting LEDs are used in side-lighting type backlight devices, then brightness and service life are improved, but uniform illumination is difficult to achieve
Solution Approach 1:
The patent applies different tilt angles to LEDs at different positions. Specifically, LEDs at end positions are tilted at 45-60 degrees, while LEDs at intermediate positions are tilted at smaller angles (15-30 degrees). This local differentiation ensures that light from end LEDs, which would otherwise create non-uniform illumination, is properly distributed across the light guide plate.
Solution Approach 2:
The patent introduces asymmetric tilt angles for LEDs at different positions along the light guide plate. Rather than using a uniform tilt angle for all LEDs, the asymmetric configuration (different angles for end vs. intermediate LEDs) compensates for the non-uniform light distribution characteristics of top-emitting LEDs, achieving uniform overall illumination.
3Manufacturing precision
If side-emitting LEDs are used, then uniform illumination can be achieved, but the service life is shortened
Solution Approach 1:
The patent changes the emission angle parameter by tilting top-emitting LEDs at specific angles (45-60 degrees for end LEDs, 15-30 degrees for intermediate LEDs). This parameter modification enables top-emitting LEDs to achieve uniform side illumination while maintaining their superior brightness and service life characteristics.
4Ease of manufacture
If conventional top-emitting LEDs are used without tilting, then the illumination direction is perpendicular to the mounting surface, but this does not facilitate uniform light distribution in side-lighting configurations
Solution Approach 1:
The patent inverts the conventional mounting approach by tilting top-emitting LEDs away from the standard perpendicular orientation. By tilting the LEDs at specific angles, the light emission is redirected to achieve uniform side illumination, resolving the contradiction between ease of manufacture and light distribution uniformity.
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 use of top-emitting LEDs with tilting portions improves the brightness and longevity of the backlight, achieving uniform illumination for liquid crystal panels by efficiently distributing light across the entire light guide plate.
Implementation Method 1
a light source unit that includes a plurality of LEDs of a top-emitting type
Implementation Method 2
a light guide plate having a light incident surface on which the light source unit is disposed and a top surface opposite to the light incident surface
Data Source
AI summary
Disclosed are a side light-type backlight device with high brightness and excellent light use efficiency, a liquid crystal display device and a television receiver. The disclosed backlight device has a light guide plate that emits, from the top surface, light that entered from the side surface thereof, a substrate that is disposed at the side surface of the light guide plate and that has a plurality of LEDs emitting light from the top aligned thereon, and an outer case enclosing the light guide plate and the substrate. Of the plurality of LEDs, the end LEDs are provided with inclined sections such that the illumination direction of said end LEDs intersect with that of the other LEDs.