Backlight Unit With Segmented LEDs For Hot Spot Reduction
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Solution Overview
Problem
Existing backlight units and display devices face challenges in achieving optimal light linearity and orientation, leading to issues such as hot spots and reduced light efficiency, particularly when using LEDs with varying optical properties.
Innovation Solution
A backlight unit and display device design that incorporates a light emitting module with a combination of first and second light emitting devices, where the first device has superior light linearity and a smaller orientation angle, and the second device has wider orientation angles, allowing for selective control by a controller to adjust local brightness and reduce hot spots through strategic placement and operation of these devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single type of LED is used in the backlight unit, then the device structure is simple, but light linearity and orientation control are insufficient leading to hot spots and reduced efficiency
Solution Approach 1:
The backlight unit is segmented into multiple types of light emitting devices (first and second light emitting devices) with different optical characteristics. This segmentation allows each device type to be optimized for specific functions, improving overall light linearity and orientation control while preventing hot spots.
Solution Approach 2:
Different regions of the backlight unit are equipped with different types of light emitting devices based on local requirements. The first light emitting devices with superior light linearity are placed in regions requiring precise light control, while the second devices with wider orientation angles are placed in regions needing broader light distribution, achieving local optimization of optical properties.
2Illumination intensity
If LEDs with wider orientation angles are used, then light distribution is improved, but light linearity deteriorates causing hot spots
Solution Approach 1:
The patent applies local quality by assigning different LED types to different spatial locations within the backlight unit. First light emitting devices with narrow orientation angles and superior light linearity are positioned where precise light control is needed, while second light emitting devices with wide orientation angles are positioned where broad light distribution is required, thereby eliminating hot spots while maintaining good overall light distribution.
Solution Approach 2:
The backlight unit employs a composite structure combining two types of light emitting devices with complementary optical properties. This composite approach integrates the advantages of both narrow-angle LEDs (superior light linearity) and wide-angle LEDs (wide orientation distribution), achieving a balance between light linearity and light distribution that neither device type could achieve alone.
3Manufacturing precision
If LEDs with superior light linearity are used, then light efficiency is improved, but orientation angle becomes too narrow limiting light coverage
Solution Approach 1:
The light emitting module is segmented into two functional groups: first light emitting devices optimized for light linearity and second light emitting devices optimized for orientation angle. This segmentation allows the system to simultaneously achieve superior light linearity where needed and wide orientation coverage where needed, enhancing both light efficiency and adaptability.
Solution Approach 2:
The backlight unit achieves multi-functionality by integrating two types of light emitting devices that serve different optical functions. The first devices provide precise light control for high efficiency, while the second devices provide broad light coverage for versatility, making the overall system adaptable to various display requirements and scenarios.
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 approach enables improved light distribution and reduced hot spots by selectively driving light emitting devices based on their optical properties, enhancing the overall brightness and efficiency of the display image.
Implementation Method 1
A light emitting diode (LED) is a semiconductor light emitting device that converts current into light
Implementation Method 2
A light emitting diode (LED) is a semiconductor light emitting device that converts current into light
Implementation Method 3
a light guide plate disposed at one side of the light emitting module to guide the light toward the display panel
Data Source
AI summary
Disclosed are a backlight unit and a display device. The backlight unit includes alight emitting module including a plurality of light emitting devices; a controller for controlling an operation of the light emitting module; a light guide plate disposed at one side of the light emitting module; and an optical member disposed on or under the light guide plate. The light emitting module includes a first light emitting device and a second light emitting device. Light linearity of the first light emitting device is superior to light linearity of the second light emitting device, and a light orientation angle of the first light emitting device is smaller than a light orientation angle of the second light emitting device. The controller selectively drives the first and second light emitting devices.