Projector Chromaticity Adjustment via Light Source Control
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Solution Overview
Problem
In projectors using a light source that emits mixed blue and yellow light, adjusting the chromaticity to achieve desired white balance is challenging due to difficulties in individually controlling the ratio of blue, red, and green light, leading to reduced light utilization efficiency when signal levels are adjusted.
Innovation Solution
A chromaticity adjustment method that involves acquiring chromaticity and luminance values of red, green, and blue light, determining a second target chromaticity value based on a first target value and the inherent values of blue light, and controlling the light quantities of the light sources and video signal levels to achieve the desired white balance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the signal level of each color component in the video signal is controlled to adjust chromaticity, then the desired white balance can be achieved, but the light utilization efficiency is reduced because the light quantity from the light sources remains constant while signal levels are lowered
Solution Approach 1:
The patent changes the control parameter from video signal level to light source quantity. By controlling the light quantity of each light source (first light source for blue, second light source for yellow) based on chromaticity values and luminance values, the system achieves chromaticity adjustment while maintaining optimal light utilization efficiency.
Solution Approach 2:
The patent implements a feedback mechanism where chromaticity values and luminance values of the projected light are measured, and based on these measurements, the light quantities of the individual light sources are adjusted to achieve the target chromaticity while maximizing light utilization efficiency.
2Adaptability or versatility
If the light quantity of the first and second light sources is controlled to adjust the ratio of blue and yellow light, then the chromaticity can be adjusted, but it is difficult to adjust the ratio of blue, red, and green light individually
Solution Approach 1:
The patent segments the yellow light into its red and green components by measuring their respective luminance values. This allows independent control of the effective contribution of red and green light to the final chromaticity by adjusting the quantity of yellow light, effectively achieving three-color control (blue from first light source, red and green from second light source) with a two-light-source configuration.
Solution Approach 2:
The second light source emitting yellow light serves multiple functions: it provides both red and green light components simultaneously. By controlling the quantity of yellow light, the system can adjust both red and green light levels without requiring separate light sources for each color, reducing device complexity while maintaining chromaticity adjustment capability.
3Illumination intensity
If the light quantity of light sources is increased to improve image brightness, then the illumination intensity improves, but the power consumption and heat generation increase requiring stronger cooling
Solution Approach 1:
The patent optimizes the light quantity parameters of each light source based on chromaticity requirements and luminance characteristics. By precisely controlling the light quantity of each source rather than uniformly increasing all light quantities, the system achieves target brightness with minimal power consumption, reducing heat generation and cooling requirements.
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 method allows for improved light utilization efficiency by reducing waste in blue, red, and green light, while maintaining desired white balance, and also reduces power consumption and noise from cooling fans by adjusting light source quantities.
Implementation Method 1
a first light source that emits blue light and a second light source that emits yellow fluorescent light
Implementation Method 2
a second light source that emits yellow fluorescent light
Implementation Method 3
The light emitted from the light source device is separated into red light, green light, and blue light
Implementation Method 4
The light modulator for red forms a red image by modulating the red light based on the red component signal
Implementation Method 5
a projection optical system that projects the image
Data Source
AI summary
A chromaticity adjusting method of a projector includes a first light source for emitting blue light and a second light source for emitting yellow light including red light and green light. A chromaticity value of the blue light is acquired and the chromaticity value and the luminance value of each of the red light and the green light is obtained. The second target chromaticity value is determined based on the first target chromaticity value, the chromaticity value of the blue light, and the chromaticity value and the luminance value of each of the red light and the green light. Light quantities of the first and second light sources are controlled based on the second target chromaticity value. Signal levels of the red, green, and blue color components included in the video signal are controlled according to the difference between the first target chromaticity value and the second target chromaticity value.