Projector Driver Voltage Control for Color Break Suppression
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Solution Overview
Problem
Projectors using a pulse width modulation method for liquid crystal panels often experience a color break phenomenon, where red, green, and blue lights are perceived instead of white when the viewer moves, due to differences in ON voltage periods across pixels, which existing methods fail to adequately address.
Innovation Solution
An image projection apparatus with a driver that generates a common voltage and a second voltage to control the light modulation elements, adjusting the pixel voltage and common electrode voltage to ensure equal light amounts and ON duty cycles for each color, thereby minimizing color break.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pulse width modulation method is used to drive liquid crystal panels, then image quality and brightness control are improved, but color break phenomenon occurs due to shifted ON periods across color channels
Solution Approach 1:
The patent changes the voltage parameter applied to liquid crystal panels by introducing a common voltage component that is added to the pixel voltage. This voltage parameter modification shifts the ON periods of different color channels to coincide, eliminating color break while preserving PWM brightness control precision.
Solution Approach 2:
The patent applies a common voltage to all liquid crystal panels simultaneously, creating an equipotential condition that synchronizes the ON periods across red, green, and blue channels. This eliminates the temporal shift between color channels that causes color break phenomenon.
2Measurement precision
If different voltages are applied to different liquid crystal panels to optimize individual performance, then image quality is improved, but luminance difference and flicker occur between frames
Solution Approach 1:
The patent modifies the voltage parameter by superimposing a common voltage signal on top of individual pixel voltages. This parameter change allows each panel to maintain its optimized performance while the common voltage component synchronizes their operation, eliminating luminance differences and flicker between frames.
3Stability of the object's composition
If common voltage is controlled to minimize luminance difference, then frame consistency is improved, but color break in pulse width modulation method is not suppressed
Solution Approach 1:
The patent extends the common voltage control parameter to include a specific time-dependent component that shifts the ON periods of different color channels into alignment. This goes beyond conventional common voltage control by adding a temporal synchronization function to the voltage parameter.
Solution Approach 2:
The patent employs periodic voltage application with specifically timed pulses that coincide across all color channels. By making the common voltage a periodic signal with synchronized timing, it eliminates color break while maintaining frame consistency through regular, predictable voltage cycles.
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 suppresses color break by ensuring consistent light projection across all colors, maintaining image quality even when light amounts differ, and allowing for both brightness and image quality priority modes without visual color breaks.
Implementation Method 1
a plurality of light modulation elements each including a plurality of pixels, and configured to modulate lights having wavelengths different from each other
Data Source
AI summary
An image projection apparatus includes light modulation elements each including a plurality of pixels, and configured to modulate lights having wavelengths different from each other, and a driver configured to generate a first voltage commonly applied to the plurality of pixels in each of the plurality of light modulation elements, and a second voltage configured to determine a maximum value of a ratio of a light amount of exit light to a light amount of incident light of the plurality of pixels, and to drive the plurality of light modulation elements through a pulse width modulation of the second voltage for each pixel according to an input image signal. The driver sets the second voltage to at least one light modulation element among the plurality of light modulation elements, which is different from that of another light modulation element and drives the light modulation elements.