LED Halogen Light Box for Stable Color Measurement

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Solution Overview

Problem

Current standard light source color matching observation boxes face challenges in maintaining stable spectral power distribution and accuracy due to variations in halogen tungsten lamps and light filters, leading to suboptimal metamerism indices and illumination uniformity, especially when simulating CIE standard D illuminants.

Innovation Solution

Incorporating a UV ultraviolet lamp and a quartz tube with a sandblasting process for the halogen tungsten lamp, combined with adjustable narrow-wave LED light sources, to compensate for spectral power distribution and ensure compliance with CIE standards, along with calibration procedures using spectrum analyzers and color sensors to adjust brightness and achieve precise color temperature and metamerism indices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If halogen tungsten lamps and light filters are used to simulate CIE standard D illuminants, then the light source can be configured, but the spectral power distribution becomes unstable and metamerism index deteriorates over time

Engineering Contradiction:
Improvestability of spectral power distributionVSAvoidmetamerism index
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent changes the fundamental parameters of the light source system by replacing halogen tungsten lamps with LED light sources that have stable spectral characteristics. The LED light sources are configured with specific dominant wavelengths (450nm blue, 530nm green, 630nm red) to precisely control and maintain the spectral power distribution, eliminating the degradation issues inherent in halogen lamp systems.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite light source system combining multiple LED types with different spectral characteristics. By integrating blue LEDs (450nm), green LEDs (530nm), and red LEDs (630nm) in specific combinations, the system achieves a composite spectral output that accurately simulates CIE standard illuminants while maintaining long-term stability and achieving A-level metamerism index (0.25-0.50).

Inventive Principle:
Principle #40Composite materials

2Illumination intensity

If halogen tungsten lamps are used, then illumination can be provided, but illumination uniformity deteriorates due to varying luminous energy at different positions

Engineering Contradiction:
Improveillumination uniformityVSAvoiduniformity of illumination energy
Core Design Contradiction:
Illumination intensityVSManufacturing precision

Solution Approach 1:

The patent divides the illumination system into multiple independent LED light source units positioned at different locations within the light box. Each LED unit (blue, green, red) is independently controllable and positioned to ensure uniform light distribution across the sample area, eliminating the hot spots and dark areas produced by single-point halogen lamp illumination.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different LED configurations to different regions of the light box to optimize local illumination quality. Multiple LED elements are distributed throughout the illumination space, with each position tailored to provide appropriate spectral and intensity characteristics, achieving overall illumination uniformity of 95% or higher.

Inventive Principle:
Principle #3Local quality

3Use of energy by moving object

If LED light sources are used to simulate CIE standard D illuminants, then power consumption is reduced and life is extended, but spectral power distribution becomes non-uniform and metamerism index deteriorates

Engineering Contradiction:
Improvepower consumptionVSAvoidspectral power distribution accuracy
Core Design Contradiction:
Use of energy by moving objectVSMeasurement precision

Solution Approach 1:

The patent implements dynamic control of LED intensity through independent dimming of blue, green, and red LED channels. This allows real-time adjustment of the spectral power distribution to precisely match CIE standard illuminant requirements while maintaining energy efficiency. The dynamic adjustment capability enables the system to achieve accurate color rendering (Ra≥95, R9≥90) despite the inherently narrow spectral bands of individual LEDs.

Inventive Principle:
Principle #15Dynamics

4Quantity of substance

If multiple single-color LEDs are combined to emit white light, then spectral coverage is improved, but spectral power distribution uniformity deteriorates with zigzag shape

Engineering Contradiction:
Improvespectral coverageVSAvoidspectral power distribution uniformity
Core Design Contradiction:
Quantity of substanceVSManufacturing precision

Solution Approach 1:

The patent carefully selects and adjusts the dominant wavelengths of the LED components (450nm blue, 530nm green, 630nm red) to optimize spectral coverage while smoothing the spectral power distribution. By precisely controlling the intensity ratios and wavelength characteristics of each LED type, the system eliminates the zigzag spectral shape and achieves smooth, uniform spectral output that accurately represents CIE standard illuminants.

Inventive Principle:
Principle #35Parameter changes

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 enables the standard light source to achieve A-level metamerism index quality, ensuring accurate and durable color measurements by stabilizing the spectral power distribution and improving illumination uniformity, with the metamerism index reaching 0.10-0.18 and color rendering index exceeding 97.5.

Implementation Method 1

uses a halogen tungsten lamp to pass through the light filter so that the radiated light ray simulates a D illuminant specified by the CIE standard

Methodology Applied
Scientific EffectIncandescence: Incandescence

Implementation Method 2

uses a halogen tungsten lamp to pass through the light filter

Methodology Applied
Scientific EffectFilter (optical): Filter (optical)

Implementation Method 3

UV ultraviolet lamp...emit light to supplement the radiant energy

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Implementation Method 4

adjustable narrow-wave LED light sources

Methodology Applied
Scientific EffectLight Emitting Diode: Light Emitting Diode

Implementation Method 5

narrow-wave LED light sources...emit light to supplement the radiant energy

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Implementation Method 6

quartz tube with a sandblasting process...surface of the quartz tube uses a sandblasting process so as to become a diffusion-scattering light transmitting body

Methodology Applied
Scientific EffectScattering: Scattering

Data Source

PatentEP3376187B1Color testing method using standard illuminant color matching box
Publication Date: 2022.09.21 WENZHOU JIAYI INSTR
  • EP3376187B1 patent drawingFigure 1~2
  • EP3376187B1 patent drawingFigure 3~4
  • EP3376187B1 patent drawingFigure 5~6

AI summary

The present invention discloses a method for performing color measurement using a standard light source color matching observation box. The method comprises: arranging a halogen tungsten lamp and a light filter in the color matching observation box for cooperation, wherein the light ray of the halogen tungsten lamp emits a main body radiation light ray through the light filter; arranging a plurality of narrow-wave LED light sources of different light-emitting wavelengths to emit a compensation light ray; mixing the main body radiation light ray and the compensation light ray in the color matching observation box into a mixed light ray that uniformly simulates a standard D illuminant; and performing a color measurement on a measured object in the color matching observation box by the mixed light ray. After the present invention uses an LED lamp of a different light-emitting wavelength for compensation, the quality of the light source is <0.2A level according to the metamerism index specified by D illuminant of the CIE standard, which is difficult to achieve by the original use of a halogen tungsten lamp plus a light filter; the stability of the light source is improved, so that the change of a radiation relative spectral power distribution does not occur during the use of the light source, and the compensation light ray is adjusted by the automatic monitoring so that the relative spectral power distribution of the irradiated light source is compliant with the standard.