Illumination Device White Balance Correction

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Solution Overview

Problem

Existing projection display systems face challenges in maintaining constant white balance due to changes in temperature, which affect the relative luminosity of light sources with wavelength-dependent temperature variations, leading to fluctuations in image brightness and color balance.

Innovation Solution

Incorporating a correction unit within the illumination device that adjusts the light quantity of light sources based on changes in relative luminosity caused by temperature changes, using a plurality of light sources with different wavelengths, and employing temperature sensors and correction units to maintain stable white balance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If temperature control elements (such as Peltier elements) are used to restrain temperature changes, then white balance stability is improved, but device complexity increases

Engineering Contradiction:

Improvewhite balance stabilityVSAvoiddevice complexity

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent replaces mechanical/thermal control elements (Peltier elements) with an optical correction approach. The correction unit adjusts the light quantities of individual light sources based on detected changes in relative luminosity, substituting a complex thermal control system with a simpler optical adjustment mechanism that achieves the same white balance stabilization goal.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the operating parameters (light quantities) of the light sources dynamically based on detected relative luminosity changes. By adjusting the intensity of individual light sources rather than controlling their temperatures, the system maintains white balance stability without requiring temperature control elements.

Inventive Principle:

Principle #35Parameter changes

2Stability of the object's composition

If light quantities of light sources are adjusted to maintain white balance, then white balance stability is improved, but image brightness uniformity deteriorates when drive currents approach limit values

Engineering Contradiction:

Improvewhite balance stabilityVSAvoidimage brightness uniformity

Core Design Contradiction:

Stability of the object's compositionVSIllumination intensity

Solution Approach 1:

The patent implements a feedback mechanism where a detection unit continuously monitors changes in relative luminosity of light sources, and the correction unit uses this feedback information to adjust light quantities. This closed-loop control ensures white balance stability while adapting to varying operating conditions, including when drive currents approach limit values.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent introduces dynamic adjustment of light source quantities based on real-time detection of relative luminosity changes. This dynamic approach allows the system to adapt to varying drive current conditions and maintain both white balance stability and image brightness uniformity across different operating ranges.

Inventive Principle:

Principle #15Dynamics

3Adaptability or versatility

If multiple light sources with different wavelengths are used, then color balance capability is improved, but sensitivity to temperature-induced wavelength changes increases

Engineering Contradiction:

Improvecolor balance capabilityVSAvoidwhite balance stability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies local quality correction by individually adjusting the light quantities of specific light sources based on their detected relative luminosity changes. Each light source's contribution to the overall color balance is independently controlled, allowing precise compensation for temperature-induced wavelength shifts while maintaining overall color balance capability.

Inventive Principle:

Principle #3Local quality

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 effectively stabilizes white balance by adjusting light quantities in response to temperature-induced wavelength changes, ensuring consistent image brightness and color balance, even when drive currents approach limit values, thereby optimizing image quality.

Implementation Method 1

The change in the relative luminosity is caused by a change in wavelength associated with a change in temperature

Methodology Applied

Scientific EffectTemperature-induced wavelength change:

Data Source

PatentUS10073331B2Illumination device and light source control method, and projection display apparatus

Publication Date: 2018.09.11 SONY GROUP CORP

AI summary

An illumination device of the disclosure includes a plurality of light sources and a correction unit. The plurality of light sources generate light having respectively different wavelengths. The correction unit corrects, on the basis of a change in relative luminosity, a light quantity of the light to be generated by at least one light source out of the plurality of light sources, to restrain a change in white balance. The change in the relative luminosity is caused by a change in wavelength associated with a change in temperature.