Varifocal Lens Projection Device Resolving Focus-Convergence Mismatch
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Solution Overview
Problem
Existing binocular displays cause a mismatch between focal length and convergence distance, leading to eye fatigue due to technical limitations in inducing accurate focus reactions and convergence reactions, with current solutions degrading resolution and being insufficient in representing depth ranges.
Innovation Solution
A projection device with a synchronized control device, projector module, and lens module that adjusts focal length and convergence distance by using a varifocal lens and binary-driven light-emitting devices to match focal length and convergence distance, allowing for precise control of light and image projection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If binocular parallax is used to induce convergence reaction, then depth perception is improved, but mismatch between focal length and convergence distance occurs causing eye fatigue
Solution Approach 1:
The patent employs a varifocal lens that dynamically adjusts its focal length to match the convergence distance induced by binocular parallax. The lens module's focal length is variable and can be changed in real-time to correspond with different depth information, thereby resolving the static mismatch between focal length and convergence distance that causes eye fatigue.
Solution Approach 2:
The system changes the optical parameter (focal length) of the lens module to match another parameter (convergence distance) determined by the display's binocular parallax. By adjusting the focal length parameter dynamically, the system ensures that the optical focus coincides with the perceived depth, eliminating the harmful mismatch effect.
2Measurement precision
If multiple depth ranges are represented, then focus reaction accuracy is improved, but resolution degradation occurs
Solution Approach 1:
The system uses time-sequential illumination where different regions of the display are illuminated in different time frames corresponding to different depth ranges. The backlight module selectively provides light to different pixel regions at different times, allowing multiple depth representations without spatial resolution loss, as each depth is represented temporally rather than spatially.
Solution Approach 2:
The varifocal lens dynamically changes focal length to match different depth planes, and the backlight module dynamically adjusts which regions are illuminated. This temporal and optical dynamic coordination allows multiple depth ranges to be represented accurately without degrading the spatial resolution of the display.
3Reliability
If varifocal lens is added to modulate virtual image depth, then mismatch between focal length and convergence distance is reduced, but device complexity increases
Solution Approach 1:
The lens module serves multiple functions: it acts as a standard viewing lens and simultaneously functions as a varifocal element for depth modulation. The same optical component handles both regular viewing and depth-adjusted viewing, reducing the need for separate dedicated components and thereby limiting the increase in device complexity.
Solution Approach 2:
The varifocal lens acts as an intermediary between the fixed-focus display and the user's eyes. Rather than modifying the display itself or requiring complex multi-component systems, a single varifocal lens module mediates the optical path, adjusting focal length as needed while keeping the overall system relatively simple.
4Illumination intensity
If backlight module provides continuous light, then image brightness is maintained, but energy consumption increases
Solution Approach 1:
The backlight module operates periodically rather than continuously, providing light only during specific time frames when corresponding depth regions need to be displayed. By pulsing the backlight in synchronization with the varifocal lens adjustments and depth information display, the system maintains necessary brightness while significantly reducing overall energy consumption.
Solution Approach 2:
The backlight provides light partially rather than fully continuously - only when and where needed for specific depth ranges. This partial illumination approach maintains adequate brightness for the active depth plane while avoiding the energy waste of continuous full-brightness illumination across the entire display.
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 matches focal length and convergence distance, reducing eye fatigue and enabling the representation of multiple depth ranges without degrading resolution, thereby improving the viewing experience.
Implementation Method 1
the lens module is configured to induce a focus reaction on the user's eyes and change a focal length of the image reproduced by the display module within a certain range
Implementation Method 2
the display module is configured to induce a convergence reaction on the user's eyes such that the image projected on the screen has a convergence distance
Implementation Method 3
binary-driven light-emitting devices to match focal length and convergence distance
Data Source
AI summary
The present disclosure relates to a projection device, and more particularly, to a projection device including: a projector module configured to provide an image to a screen; and a lens module between a user's eyes and the screen, wherein the project module includes: a display module configured to provide a certain image; and a backlight module configured to provide light to the display module such that the image provided by the display module is projected on the screen, wherein the display module is between the backlight module and the screen, the display module is configured to induce a convergence reaction on the user's eyes such that the image projected on the screen has a convergence distance, and the lens module is configured to induce a focus reaction on the user's eyes and change a focal length of the image reproduced by the display module within a certain range.