Dichroic Filter for Laser Display Color Gamut and Efficiency
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Solution Overview
Problem
Conventional display devices face challenges in matching the BT. 2020 color standard due to the wide color range requirement, particularly with red semiconductor lasers, which compromise power consumption and light emission efficiency when trying to conform to the 630 nm wavelength, while existing solutions focus on widening the color range rather than narrowing it to meet the standard.
Innovation Solution
A display device structure that includes a dichroic transmission filter in red pixels to pass red laser light and part of green laser light, allowing the use of red semiconductor lasers with higher light emission efficiency at 638 nm, thereby matching the BT. 2020 color standard while optimizing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a red semiconductor laser with wavelength of 630 nm is used to conform to the BT. 2020 standard, then the color range matches the standard, but the light emission efficiency greatly decreases
Solution Approach 1:
The patent changes the wavelength parameter of the red semiconductor laser from the standard-compliant 630 nm to a more efficient wavelength range (635-645 nm). This parameter change allows the system to maintain acceptable color reproduction while dramatically improving light emission efficiency and reducing power consumption.
Solution Approach 2:
The patent introduces a dichroic transmission filter with specific spectral characteristics that allows it to selectively transmit the red laser light at the adjusted wavelength while maintaining the required color gamut. The filter's local optical properties are optimized to compensate for the wavelength deviation from the standard.
2Loss of energy
If a red semiconductor laser with wavelength of approximately 638 nm is used, then the light emission efficiency increases, but the color range deviates from the BT. 2020 standard
Solution Approach 1:
The dichroic transmission filter acts as an intermediary between the red semiconductor laser and the display panel. It selectively transmits the laser light at wavelengths that enable both efficient laser operation and acceptable color reproduction, mediating between the conflicting requirements of laser efficiency and color accuracy.
Solution Approach 2:
The patent employs a composite optical system consisting of the red semiconductor laser, dichroic transmission filter, and display panel. The filter's multi-layer structure combines different optical properties to achieve the desired spectral transmission characteristics that bridge the gap between laser efficiency and color standard compliance.
3Manufacturing precision
If the color range is widened to conform to the BT. 2020 standard, then the color gamut increases, but the power consumption increases
Solution Approach 1:
The patent optimizes the wavelength parameter of the red laser and the spectral transmission characteristics of the dichroic filter to achieve a balance between color gamut and power consumption. By adjusting these parameters, the system maintains a color gamut that meets practical display requirements while significantly reducing the power consumption associated with driving the red laser at lower efficiency wavelengths.
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 proposed solution enables a high-quality display device with excellent color reproducibility by mixing laser lights of different chromaticity coordinates, achieving a better match with the BT. 2020 color standard and reducing power consumption by utilizing red semiconductor lasers with optimal emission efficiency.
Implementation Method 1
a dichroic transmission filter in red pixels to pass red laser light and part of green laser light
Implementation Method 2
red semiconductor laser emits laser light of a color in fourth chromaticity coordinates which is different from the first defined color
Implementation Method 3
laser light which can be efficiently extracted from a red semiconductor laser (laser diode) has, for example, a wavelength of approximately 638 nm
Data Source
AI summary
According to one embodiment, a display device displays a color gamut defined by connecting a first defined color in first chromaticity coordinates, a second defined color in second chromaticity coordinates, and a third defined color in third chromaticity coordinates. An illumination device of the display device includes green, blue and red lasers. The green and blue lasers emit light of the second and third defined colors, and red laser emits light of a color in fourth chromaticity coordinates. Each of the pixels displays a color including the first defined color by mixing light in the fourth chromaticity coordinates and the second defined color.