Projection Display Light Source Polarity Inversion Control
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Solution Overview
Problem
The existing projection-type image display devices face issues with maintaining the stability of the light source and image quality due to inconsistent current pulses during color transitions, leading to polarity inversion with low current values, which reduces the lifetime of the light source and image display quality.
Innovation Solution
A control unit dynamically adjusts current values and polarity inversion timing based on the color components of the input image signal, ensuring the current values meet the required levels for the light source, even during specific color periods, and synchronizes these adjustments with the rotation cycle of the color wheel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If current pulse is supplied at constant interval for each color, then the application timing is simple to control, but the current value does not reach the predetermined current value during specific color periods, causing polarity inversion with low current value and reducing light source stability
Solution Approach 1:
The patent applies dynamics by making the polarity inversion timing adaptable rather than fixed. The control unit dynamically adjusts the polarity inversion timing based on the color period characteristics, ensuring that inversion occurs only when the current value reaches the predetermined level. This dynamic adjustment resolves the contradiction by maintaining control simplicity while ensuring light source stability through context-aware timing selection.
Solution Approach 2:
The patent changes the timing parameter of polarity inversion based on the color period. Instead of using a fixed constant interval, the system adjusts the inversion timing parameter according to the specific color being displayed, ensuring that the current value always reaches the predetermined level before inversion. This parameter change approach maintains operational simplicity while guaranteeing light source stability.
2Productivity
If polarity inversion is performed with low current value, then the operation can proceed without delay, but the arc discharge stability decreases and image display quality deteriorates
Solution Approach 1:
The patent applies preliminary action by ensuring that the current value reaches the predetermined level before polarity inversion is performed. The control unit monitors the current waveform and schedules the inversion operation to occur at the optimal moment when sufficient current has been established. This preliminary preparation ensures arc discharge stability is maintained while minimizing any potential delay in operation.
3Duration of action of stationary object
If the current value is increased to reach the predetermined current value, then the light source lifetime increases, but the current waveform becomes inconsistent during specific color periods, affecting color balance
Solution Approach 1:
The patent applies local quality by applying different current control strategies to different color periods. The control unit identifies specific color periods where the current value tends to decrease and applies extended current pulses or adjusted timing specifically for those colors. This localized adjustment ensures the predetermined current value is reached during critical periods without disrupting the overall color balance, thereby extending light source lifetime while maintaining composition stability.
Solution Approach 2:
The patent uses feedback by continuously monitoring the current waveform and color output. The control unit adjusts the current pulse timing and duration based on feedback from the actual current values during each color period. This feedback mechanism ensures that the current value reaches the predetermined level for light source protection while automatically compensating for any color balance shifts, maintaining both lifetime and color accuracy.
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 enhances the lifetime of the light source and improves image quality by maintaining stable arc discharge and color balance, while reducing flickering and color balance changes.
Implementation Method 1
increasing the current intensity of the light source, thereby improving the stability of the arc discharge in the light source
Implementation Method 2
a color generation unit that is provided on an optical path of emitted light from the light source unit, the color generation unit being configured to generate a plurality of colors of light from the emitted light in a time-division manner by rotating at a predetermined rotation cycle
Data Source
AI summary
The projection-type image display device includes a light source unit, a color generation unit provided on the optical path of emitted light from the light source unit and configured to generate multiple colors of light from emitted light from the light source in a time-division manner by rotating at a predetermined rotation cycle, a light modulation unit, and a control unit. In accordance with a color component of the input image signal, the control unit sets current values for current to be applied to the light source unit and a polarity inversion timing for inverting the polarity of the light source unit. The control unit applies current having the current values to the light source unit while inverting the polarity according to the polarity inversion timing. The control unit shifts the polarity inversion timing according to change in the current values for current to be applied to the light source unit.