LED Illumination Device with Sensor Feedback Control for Color Consistency
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Solution Overview
Problem
Existing illumination devices with multiple LED sources experience significant variation in light output due to individual differences and temperature changes, leading to inconsistent color and brightness, which is not adequately addressed by current control methods.
Innovation Solution
An illumination device with a sensor and controller that alternates between single color and mixed color periods to detect and adjust the light output of multiple LED sources, ensuring consistent light output by integrating detection values over multiple cycles and using phase shift control to minimize color variation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple LED chips with different emission colors are used to provide varied light output, then the illumination device can achieve diverse lighting effects, but variation in light output increases due to individual differences and temperature changes
Solution Approach 1:
The patent implements a feedback control system where a light detection element (sensor) continuously monitors the light output from LED chips, and a controller adjusts the drive current to each LED chip based on the sensor feedback. This closed-loop control compensates for individual differences and temperature-induced variations, maintaining consistent color and brightness across multiple LED chips with different emission colors.
Solution Approach 2:
The patent dynamically adjusts the drive current parameters supplied to each LED chip based on real-time detection data. By changing the electrical parameters (current magnitude) in response to detected light output variations, the system compensates for individual LED characteristics and temperature effects, achieving consistent illumination despite using multiple LED chips with different emission colors.
2Reliability
If light output of each LED chip is adjusted separately to reduce variation, then color consistency improves, but detection accuracy is insufficient to achieve further reduction in light output variation
Solution Approach 1:
The patent employs periodic detection and adjustment cycles where the sensor repeatedly measures light output from each LED chip at predetermined intervals, and the controller performs sequential adjustments based on these periodic measurements. This periodic feedback approach enables accurate detection of individual LED chip characteristics and continuous refinement of drive currents to achieve precise light output consistency.
Solution Approach 2:
The patent performs preliminary detection of light output characteristics for each LED chip during initialization or calibration phases before normal operation. This preliminary measurement establishes baseline data for each individual LED chip, allowing the controller to pre-adjust drive currents to compensate for individual differences before actual illumination begins, thereby improving overall detection accuracy and light output consistency.
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 significantly reduces light output variation and color inconsistency by accurately controlling the light sources based on real-time detection data, maintaining stable brightness and color across multiple illumination devices.
Implementation Method 1
a sensor (2) configured to detect a light amount of the light source portion (1a)
Data Source
AI summary
An illumination device includes a first light source and a second light source, a sensor, and a controller. The controller repeats a plurality of operation cycles, one operation cycle being a set of a first period in which only a detection target light source is caused to emit light and a second period in which the first light source and the second light source are caused to emit light. The sensor outputs detection values of detected light amounts in the first period. The controller controls the light source such that light amount of the light source fall in a target range, based on a detection result that corresponds to a value corresponding to the detection values of the light amount detected a predetermined number of times.