Illumination Device Thermal Expansion Brightness Unevenness
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Solution Overview
Problem
Existing illumination devices in liquid crystal display devices suffer from brightness unevenness due to thermal expansion of light distribution adjustment members, which affects the light distribution and visibility, and the design with gaps between these members leads to further light loss and unevenness.
Innovation Solution
The illumination device incorporates a light source with a first optical member having a light reflection portion and a transmitting portion, where the center of the light reflection portion adjusts its position relative to the light source as temperature changes, ensuring optimal overlap and minimizing brightness unevenness through a controlled light distribution pattern and the use of a control unit to adjust light emission based on temperature and elapsed time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If light distribution adjustment members are arranged along the light emission direction to suppress brightness unevenness, then thermal expansion brightness unevenness is suppressed, but gaps between members cause light loss and brightness unevenness
Solution Approach 1:
The patent merges multiple light distribution adjustment members into a single integrated member with multiple light reflection portions. This eliminates the gaps between separate members that caused light loss, while maintaining the ability to control light distribution from multiple LED rows. The single member structure ensures continuous light modulation without the energy loss associated with gaps between discrete components.
Solution Approach 2:
The light distribution adjustment member is segmented into multiple light reflection portions, each corresponding to a specific LED row. This segmentation allows independent optimization of light control for each LED row while maintaining a continuous structure without gaps. Each light reflection portion can be independently designed to handle thermal expansion and maintain proper alignment with its corresponding LED row.
2Manufacturing precision
If light distribution adjustment members are fixed in position, then alignment with LEDs is maintained, but thermal expansion causes printed patterns to displace and lose light distribution function
Solution Approach 1:
The patent incorporates thermal expansion parameters into the design of the light distribution adjustment member. The member is designed with specific material properties and geometric configurations that allow it to expand thermally while maintaining the functional relationship between printed patterns and LED positions. By pre-calculating and compensating for thermal expansion parameters, the system maintains alignment precision across temperature variations without requiring active adjustment mechanisms.
3Measurement precision
If the center of light reflection portion is positioned to overlap LED center at all temperatures, then alignment is optimal, but thermal expansion causes displacement and brightness unevenness
Solution Approach 1:
The patent positions the center of each light reflection portion to overlap with the center of its corresponding LED row at a reference temperature before assembly. This preliminary positioning ensures optimal alignment under standard conditions. The design then compensates for subsequent thermal expansion through the inherent flexibility and material properties of the light distribution adjustment member, allowing it to maintain functional alignment across temperature ranges without requiring active repositioning.
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 configuration effectively suppresses brightness unevenness and ensures consistent light distribution across the display, enhancing image quality by maintaining the positional relationship of the light reflection pattern with respect to the LEDs even during thermal expansion, thereby reducing visual recognition of LEDs and improving display quality.
Implementation Method 1
a light reflection portion configured to reflect light
Implementation Method 2
a light transmitting portion configured to transmit light
Implementation Method 3
brightness unevenness due to thermal expansion of the light distribution adjustment members
Data Source
AI summary
An illumination device includes a light source, a first optical member, and a fixing portion. The first optical member includes a light reflection portion configured to reflect light, at least a part of the light reflection portion overlapping with the light source, and a light transmitting portion configured to transmit light, the light transmitting portion not overlapping the light reflection portion. A center of the light source in a plan view is defined as a first center, and a center of the light reflection portion in a plan view is defined as a second center. In the light reflection portion, the second center is located between the fixing portion and the first center at a first temperature, and at a second temperature higher than the first temperature, a position of the second center is closer to the first center than a position of the second center at the first temperature.