Angle-Selective Light Reflecting Unit for Display Luminance Uniformity
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Solution Overview
Problem
Conventional liquid crystal display devices experience luminance unevenness due to the uneven distribution of light reflected by half mirrors in backlight devices, leading to variations in brightness and color across the display.
Innovation Solution
A lighting device comprising a light source, a light reflecting unit with an angle selecting property to reflect light more at smaller incident angles, and a light diffusing unit to distribute light evenly, is integrated into a display device to improve luminance uniformity. The light reflecting unit, such as a blue light reflection sheet, and the light diffusing units, like first and second light diffusion sheets, work together to ensure consistent light distribution across the display panel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a half mirror is used to reflect light in the backlight device, then light can be directed toward the display panel, but luminance unevenness occurs because reflected light concentrates near the light source and does not spread evenly to regions between adjacent light sources
Solution Approach 1:
A light diffusing sheet is introduced as an intermediary component between the light source and the half mirror. This diffusing sheet scatters the light before it reaches the half mirror, ensuring that the reflected light is distributed more uniformly across the display panel. The diffusing sheet acts as a mediator that transforms the concentrated light from point sources into a more uniform illumination pattern, thereby resolving the luminance unevenness problem while maintaining the light directing function of the half mirror.
Solution Approach 2:
The patent applies preliminary diffusion of light before it reaches the half mirror. By placing the light diffusing sheet in the light path between the light source and the half mirror, the light is pre-diffused and redistributed before reflection. This preliminary action ensures that when the half mirror reflects the light, the reflected light already has a more uniform spatial distribution, preventing the concentration of luminance near the light source positions.
2Illumination intensity
If light sources are arranged in plurals on the base body, then sufficient light can be provided for the display, but luminance unevenness occurs due to the specific reflection characteristics of the half mirror
Solution Approach 1:
The light diffusing sheet serves as a mediator that uniformizes the light from multiple light sources before they interact with the half mirror. This intermediary component ensures that the combined light field from all light sources is redistributed uniformly, allowing the system to maintain high overall luminance while achieving uniform luminance distribution across the display panel.
Solution Approach 2:
The patent introduces local diffusion of light at the position of the light diffusing sheet, which is located between the light sources and the half mirror. This local quality change in the light path transforms the spatial distribution characteristics of light from each individual source and their combined effect, creating a uniformly distributed light field that maintains high overall luminance while eliminating local luminance unevenness.
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 solution effectively reduces luminance unevenness and color inconsistencies by reflecting and diffusing light in a manner that ensures uniform light distribution, enhancing the display quality of liquid crystal display devices.
Implementation Method 1
a light reflecting unit that is arranged on an exit side of a light exit path with respect to the light source to reflect at least a part of a light emitted from the light source and transmit a part of the light
Implementation Method 2
a light diffusing unit that is arranged between the light source and the light reflecting unit in the light exit path to diffuse the light
Data Source
AI summary
A lighting device includes a light source, a light reflecting unit, and a light diffusing unit. The light reflecting unit is arranged on an exit side of a light exit path with respect to the light source to reflect at least a part of a light emitted from the light source and transmit a part of the light. The light reflecting unit has an angle selecting property such that a reflectance of a light having a small incident angle becomes higher than a reflectance of a light having a large incident angle. The light diffusing unit is arranged between the light source and the light reflecting unit in the light exit path to diffuse the light.