Lighting Apparatus Maintaining Contrast Index During Color Temperature Adjustment
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Solution Overview
Problem
Conventional lighting systems face challenges in maintaining vividness and desirable color appearance as color temperature increases, leading to unintended changes in color desirability when varying the color temperature of illuminating light.
Innovation Solution
A lighting apparatus with multiple light sources of different emission spectrums, an operation unit for setting color temperature, and a control unit that adjusts the output of these sources to maintain a Feeling of Contrast Index (FCI) higher than 123 and a variation width within 10, allowing for easy color variation while maintaining vividness and desirable appearance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the color temperature of illuminating light is increased, then the illuminating power and energy efficiency are improved, but the feeling of contrast index (FCI) is lowered and color vividness deteriorates
Solution Approach 1:
The patent segments the light source into multiple LED types with different emission spectrums (first LED with peak wavelength 430-470nm, second LED with peak wavelength 560-630nm, third LED with peak wavelength 600-680nm). By controlling the output ratio of each segmented light source individually, the system can maintain high energy efficiency while preserving color vividness through coordinated output control.
Solution Approach 2:
The patent changes the emission spectrum parameters by combining multiple LED types with different peak wavelengths and controlling their output ratios. The control unit adjusts the output ratio of each LED type to maintain FCI above 123 while achieving desired color temperatures, thereby changing the spectral composition parameters to resolve the contradiction between energy efficiency and color vividness.
2Adaptability or versatility
If the color temperature of illuminating light is varied to change atmosphere, then the adaptability is improved, but the color appearance desirability deteriorates due to FCI reduction
Solution Approach 1:
The patent implements dynamic control of LED output ratios based on the desired atmosphere. The control unit dynamically adjusts the output ratio of each LED type according to the target color temperature while maintaining FCI above 123. This dynamic adjustment allows atmosphere variation while preserving color appearance desirability through real-time spectral optimization.
Solution Approach 2:
The patent employs feedback control where the control unit receives color temperature settings and adjusts LED output ratios to maintain FCI above 123. The system uses the FCI as a feedback parameter to ensure that color appearance desirability is preserved while achieving the desired atmosphere, creating a closed-loop control system that resolves the contradiction between adaptability and reliability.
3Ease of manufacture
If multiple light sources with different emission spectrums are used to maintain high FCI across color temperatures, then the device complexity increases, but the color rendering performance is improved
Solution Approach 1:
The patent makes the lighting system multi-functional by using three types of LEDs that can collectively achieve multiple color temperatures while maintaining high FCI. The same set of LEDs (first, second, and third LEDs with different peak wavelengths) serves multiple functions: achieving various color temperatures, maintaining color vividness, and providing atmosphere adjustment, thereby justifying the increased device complexity through enhanced color rendering performance.
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 ensures that the FCI remains higher than 123 when changing color temperature, enabling easy adjustment of illuminating light color to match desired atmospheres while preserving the vividness and desirability of visual objects.
Implementation Method 1
a lighting apparatus has been known in which a color gamut area is increased by additive color mixing of light from red, blue, green, and white LEDs
Implementation Method 2
a lighting apparatus includes a red LED; a green LED; a blue LED; and a white LED made up of a blue light-emitting element and a yellow phosphor
Implementation Method 3
a white LED made up of a blue light-emitting element and a yellow phosphor
Data Source
Figure 1~2E
Figure 3A~4
Figure 5~6
AI summary
To provide a lighting apparatus capable of easily varying the color of illuminating light in accordance with a desired atmosphere while maintaining vividness of a visual object illuminated with the light, and desirable color appearance. A lighting apparatus 1 includes: two or more types of light sources 2 having different emission spectrums; a controller 3 that allows setting of a color temperature of illuminating light from the light sources 2; and a control unit 4 that individually controls outputs of the light sources 2 so that the illuminating light has the color temperature set by means of the controller 3. The control unit 4, when the controller 3 has been operated to change the set color temperature, controls outputs of the light sources 2 so that the color temperature is varied in a state where a feeling of contrast index FCI is higher than 123 and a variation width of the FCI keeps within 10. Since the FCI is maintained at a value higher than 123 when the color temperature is changed, the color of the illuminating light can be easily varied in accordance with a desired atmosphere while maintaining vividness of a visual object illuminated by the illuminating light, and the desirable color appearance.