Holographic Display Optical Switching Unit for Luminance Stabilization
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Solution Overview
Problem
Holographic image display devices experience unstable luminance and flicker due to the slow liquid crystal response time and the blinking technique used to prevent imperfect images, which leads to eye fatigue and unclear images.
Innovation Solution
A holographic image display device with an optical switching unit that controls the polarization of laser light, blocking it during pixel filling and transmitting it after completion, using first and second polarizing plates and a liquid crystal cell to stabilize luminance and reduce flicker.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If the laser backlight unit is continuously turned on, then the holographic image display can be maintained, but light reaches the viewing point during liquid crystal driving causing imperfect images
Solution Approach 1:
The patent divides the operation into two distinct phases: a first period where the laser backlight unit is off and liquid crystal driving is performed, and a second period where the laser backlight unit is on and image display is performed. This temporal segmentation prevents light from reaching the viewing point during liquid crystal driving, eliminating imperfect images while maintaining continuous operation capability.
2Manufacturing precision
If the blinking technique is used to turn off the laser backlight unit during liquid crystal driving, then imperfect images are eliminated, but luminance becomes unstable and flicker occurs
Solution Approach 1:
The patent introduces a warm-up period before the second period where the laser backlight unit is turned on gradually. This preliminary action allows the laser light to reach a saturation state and stabilize before actual image display begins, preventing luminance instability and flicker while maintaining the benefits of the blinking technique.
3Manufacturing precision
If the laser backlight unit is turned on only after liquid crystal driving is complete, then perfect images are displayed, but eye fatigue occurs due to unstable luminance
Solution Approach 1:
The patent implements a warm-up period within the second period where the laser backlight unit is activated and allowed to stabilize before full image display. This preliminary stabilization of luminance prevents eye fatigue caused by unstable light conditions, while still maintaining the temporal separation that ensures perfect image 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 stabilizes luminance and reduces flicker, allowing for continuous, clear, and comfortable holographic image display without the need for laser backlight unit on/off, thereby alleviating eye fatigue and ensuring a natural image projection.
Implementation Method 1
an optical switching unit located between the laser backlight unit and the SLM and controlling polarization of the laser light
Implementation Method 2
The optical switching unit may include first and second polarizing plates having polarizing characteristics in which polarization directions thereof are perpendicular to each other, and a liquid crystal cell located between the first and second polarizing plates
Data Source
AI summary
Disclosed are a holographic image display device and a method for driving the same which may stabilize luminance of a holographic image and reduce flicker. The holographic image display device includes a laser backlight unit, a surface light converter converting laser light emitted from the laser backlight unit into surface light-type laser light and emitting the surface light-type laser light, a spatial light modulator (SLM) implementing an input holographic interference pattern and projecting a holographic image at a viewing point using the surface light-type laser light, and an optical switching unit located between the laser backlight unit and the SLM and controlling polarization of the laser light. The optical switching unit blocks laser light emitted to the SLM in a blocking mode, and transmits the laser light emitted to the SLM in a transmission mode.