Projector Color Wheel Timing Control for Gradation Repeatability
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Solution Overview
Problem
Conventional projectors experience discontinuous gradation in images due to varying light emission amounts from light emitting devices, which affects the mixing of colors during the spoke period, leading to inconsistent image quality.
Innovation Solution
A projector system that includes a light source unit with a semiconductor light emitting element and a color wheel, a delay time setting module to adjust the start timing of color mixing periods based on light brightness, and a light source driving module to drive the light source unit accordingly, ensuring consistent light emission across different color modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the driving current of the light emitting device is varied depending on color mode to enhance brightness or chromaticity, then image quality in specific color modes is improved, but discontinuous gradation occurs in the gradational image
Solution Approach 1:
The patent applies preliminary action by setting components of colors of light in advance during the spoke period. The delay time setting module pre-determines the timing for switching light emitting devices and mixes colors of light before they are displayed, ensuring that gradation repeatability is maintained even when driving current varies for different color modes.
Solution Approach 2:
The patent introduces an intermediary mechanism through the delay time setting module that mediates between the varying driving currents and the final color mixing. This module adjusts the timing of light emission from different devices, creating a buffer that ensures consistent gradation output despite variations in individual device performance.
2Adaptability or versatility
If colors of light are mixed up in the spoke period to enhance image quality, then color mode flexibility is improved, but light emission amount varies causing discontinuous gradation
Solution Approach 1:
The patent applies dynamics by making the color mixing process adaptable through the delay time setting module. This module dynamically adjusts the timing and components of colors of light based on the selected color mode, allowing the system to flexibly switch between different color modes while maintaining consistent light emission amounts and continuous gradation.
3Device complexity
If light emitting devices are driven in time division with a color wheel to emit multiple colors, then device complexity is reduced compared to using multiple light sources simultaneously, but discontinuous gradation occurs due to varying emission amounts
Solution Approach 1:
The patent applies preliminary action by pre-mixing colors of light during the spoke period before they reach the display device. The delay time setting module determines in advance which light emitting devices should emit light and for how long, ensuring that the mixed colors maintain consistent emission amounts and continuous gradation, thereby resolving the reliability issue while keeping the time-division structure.
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 maintains gradation repeatability and improves image quality by adjusting the timing of color mixing periods, reducing discontinuities in image projection across various color modes.
Implementation Method 1
a light source unit (60) including a semiconductor light emitting element (71, 121)
Implementation Method 2
a color wheel (201) and configured to emit a plurality of colors of light
Data Source
AI summary
A projector of the present invention includes a light source unit including a semiconductor light emitting element and a color wheel and emitting lights in first and second wavelength ranges in time division, a display device receiving light source light to form image light, a projection optical system for projecting the image light onto a projection target, a delay time setting module for shifting a start timing of a color mixing period when the lights in the first and second wavelength ranges are emitted in a mixed fashion in a spoke period of the color wheel during which emissions of the lights in the first and second wavelength ranges are switched over based on an index indicating a brightness of light from the light source unit, and a light source driving module for driving the light source unit based on a setting set by the delay time setting module.