Projector Retardation Plate Control for White Balance Stability
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Solution Overview
Problem
Existing projector technologies face challenges in maintaining white balance due to changes in solid-state light sources or phosphors over time, leading to issues with brightness and color balance adjustments when controlling the retardation plate.
Innovation Solution
A projector system that includes a light-emitting element, a retardation plate, a polarization separation element, and an optical modulator, where the retardation plate's rotation angle is controlled based on brightness information, and the light-emitting element's brightness is adjusted using both brightness and temperature information, allowing for simultaneous adjustment of color balance and brightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the retardation plate is controlled to maintain color balance, then color balance is improved, but brightness changes
Solution Approach 1:
The system changes multiple parameters simultaneously - both the rotation angle of the retardation plate (affecting color balance) and the drive current to the light-emitting element (affecting brightness) - to achieve the desired color balance while maintaining constant brightness output
Solution Approach 2:
The control unit uses feedback from measured brightness information to adjust the drive current of the light-emitting element, compensating for brightness changes that occur when the retardation plate rotation angle is adjusted for color balance correction
2Reliability
If the light source characteristics change over time, then reliability is improved through compensation, but device complexity increases
Solution Approach 1:
The system employs feedback control where the control unit continuously measures brightness information and adjusts both the retardation plate rotation angle and light-emitting element drive current to compensate for changes in light source characteristics over time, maintaining stable white balance
Solution Approach 2:
The control unit performs multiple functions - it controls both the retardation plate rotation for color balance adjustment and the light-emitting element drive current for brightness compensation, consolidating multiple control tasks into a single multi-functional device
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 approach enables precise control of color balance and brightness, ensuring that the projector maintains optimal performance despite changes in the light source characteristics, while also allowing user-set brightness adjustments.
Implementation Method 1
a retardation plate that converts a portion of the light output from the light-emitting element into a second polarization state in accordance with a rotation angle of the retardation plate
Implementation Method 2
a polarization separation element that separates the light from the retardation plate into a first flux of light in the first polarization state and a second flux of light in a second polarization state
Implementation Method 3
a phosphor, excited by the first flux of light, which outputs a third flux of light of a second wavelength band different from the first wavelength band
Data Source
AI summary
A projector includes a light-emitting element that outputs light of a first wavelength band which is in a first polarization state; a retardation plate that converts a portion of the light into a second polarization state; a polarization separation element that separates the light from the retardation plate into a first flux of light in the first polarization state and a second flux of light in a second polarization state; a phosphor, excited by the first flux of light, which outputs a third flux of light of a second wavelength band; a retardation plate control unit that controls a rotation angle of the retardation plate in accordance with brightness information indicating brightness of the third flux of light; and a light-emitting element control unit that controls brightness of the light-emitting element in accordance with the brightness information and temperature information indicating a temperature of the light-emitting element.