Light Field Display Zoom Lens Control via Periodic Focal Length Switching
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Solution Overview
Problem
Current light field near eye displays face challenges in achieving precise control of zoom lens elements, leading to suboptimal image formation and increased complexity in optimization control methods.
Innovation Solution
A control method for light field displays that periodically switches the zoom lens among specific focal lengths and controls the response time of image lights passing through the zoom lens, using a simple periodic function to achieve closer alignment with theoretical imaging positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optimization control methods are used to generate output close to ideal step function output, then control precision of zoom lens element is improved, but device complexity increases
Solution Approach 1:
The patent transforms the control approach from attempting to generate ideal step function outputs to using sinusoidal voltage signals with specific frequencies and amplitudes. By changing the control parameter from complex optimization sequences to simple periodic signals, the system achieves precise focal length control while greatly simplifying the control method.
Solution Approach 2:
The patent applies periodic sinusoidal voltage signals to control the zoom lens element instead of complex optimization control sequences. The periodic nature of the sinusoidal signal at specific frequencies enables precise and repeatable focal length transitions, reducing control complexity while maintaining high precision.
2Productivity
If zooming frequency is increased to improve productivity, then image formation speed is improved, but zooming power decreases significantly
Solution Approach 1:
The patent dynamically adjusts the control voltage parameters (frequency and amplitude) based on the desired focal length transitions. By optimizing the sinusoidal signal characteristics for each specific zooming operation, the system maintains high zooming power even at increased frequencies, resolving the trade-off between speed and power.
3Ease of operation
If step function output is used to control zoom lens element, then control method is simplified, but actual output signal differs from ideal output
Solution Approach 1:
The patent replaces ideal step function outputs with periodic sinusoidal signals that can be easily generated and controlled. The sinusoidal signals naturally transition between focal lengths in a smooth, predictable manner, achieving both simplicity in control method and accuracy in output signal.
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 simplifies the control method, reduces the complexity of zoom lens control, and ensures that the actual imaging position of the image light is close to the theoretical value, improving the overall imaging quality.
Implementation Method 1
The zoom lens element may include, for example, a liquid crystal tunable lens
Implementation Method 2
The microlens array projects light field sub-images of the display panel to a retina of the user
Data Source
AI summary
A control method of a light field display is provided. A control unit inputs a focal length signal to a zoom lens, so that the zoom lens is periodically switched among corresponding specific focal lengths. The control unit inputs a corresponding display signal to a display unit of a display module according to one of the specific focal lengths, and the display module generates one of image lights, the image lights respectively have different imaging distances corresponding to the specific focal lengths after passing through the zoom lens. The control unit inputs a corresponding response time signal to the display module according to one of the specific focal lengths, the one of image lights emitted by the display module passes through the zoom lens within one of response times, and the light field display projects the one of image lights to form an image at the corresponding imaging distance.