Virtual Retina Display Optical System for Gesture Detection
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Solution Overview
Problem
Current virtual retina display systems do not effectively account for the user's eye state when projecting images and detecting gestures, limiting the accuracy and adaptability of image projection and gesture recognition.
Innovation Solution
An optical system comprising a projector unit with time-modulable light sources, controllable deflection units, and sensors to project image content onto the retina and detect gestures, using infrared wavelengths for reduced interference and improved detection, with a computing unit to adjust image projection based on pupil position and gesture data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If virtual retina display systems project images without accounting for user's eye state, then the system complexity is reduced, but the accuracy of image projection and gesture detection deteriorates
Solution Approach 1:
The optical system integrates multiple functions into a unified architecture: the same light sources (visible and infrared) and deflection units (MEMS mirrors) are used for both image projection and eye state/gesture detection. The computing unit processes multiple types of data (pupil position, eye state, gestures) to control the image source, creating a multi-functional system that resolves the contradiction between measurement precision and device complexity
Solution Approach 2:
Infrared light beams serve as an intermediary medium that enables eye state and gesture detection without interfering with visible light image projection. The infrared wavelengths (including 1440 nm where sunlight has a gap) act as a separate channel for sensing, allowing the system to achieve high measurement precision while maintaining manageable complexity through wavelength division
2Measurement precision
If virtual retina display systems use infrared light for gesture detection, then the detection accuracy is improved, but the device complexity increases due to additional light sources and sensors
Solution Approach 1:
The system merges visible light and infrared light paths into a single optical architecture. The same MEMS deflection units and sensor arrays handle both visible image projection and infrared gesture detection, combining multiple functions into shared hardware components. This merging approach improves gesture detection accuracy while minimizing the increase in device complexity through component sharing
Solution Approach 2:
The system utilizes different wavelength parameters (visible light for imaging, infrared light for detection) to achieve multiple functions. By changing the wavelength parameter of the light sources and sensors, the system can optimize for both image projection and gesture detection accuracy without requiring entirely separate hardware systems, thus managing device complexity
3Adaptability or versatility
If the optical system uses multiple wavelengths of light, then the adaptability to different detection needs is improved, but the loss of energy increases due to multiple light sources
Solution Approach 1:
The system employs time-modulable light sources that emit visible and infrared light in periodic or time-multiplexed sequences rather than continuously. The light sources are activated only when needed for specific functions (image projection or gesture detection), reducing energy loss while maintaining adaptability to different detection needs through temporal separation of functions
Solution Approach 2:
The same physical infrastructure (deflection units, sensors, computing unit) serves multiple wavelength-based functions. By making the system multi-functional rather than requiring separate dedicated systems for each wavelength, the energy loss is minimized through shared hardware while adaptability to different detection needs is maintained through software-controlled wavelength selection
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
Enhances the accuracy and adaptability of image projection and gesture detection by accounting for the user's eye state, allowing for optimal image alignment and seamless gesture recognition, even in varying lighting conditions.
Implementation Method 1
a first sensor (26a) which is designed to detect at least one first portion (8a) of the second light beam backscattered from an external ocular surface, in particular the iris or sclera, of the user
Implementation Method 2
a second sensor (25) which is designed to detect at least one second portion (8b) of the second light beam backscattered from a body part, in particular a hand (16), of the user arranged within the gesture detection area (10)
Implementation Method 3
a deflection unit (7), onto which the image content is projectable and which is configured to direct the projected image content and at least the first portion (8a) of the second light beam onto an eye (13) of a user
Implementation Method 4
a second, in particular fixed, deflection unit (6), which is designed to transmit the first scanned light beam and at least a first portion (8a) of the second scanned light beam. Further, the second deflection unit is used to deflect a second portion (8b) of the second scanned light beam into a gesture detection area (10)
Data Source
AI summary
An optical system for a virtual retina display and a gesture detection of a user of the virtual retina display. The optical system includes a projector unit, an image source, and an image processing unit. The projector unit includes a first, second, and a third light source, and a first controllable deflection unit for scanning deflection of first, second, and third light beams. The optical system further includes a second deflection unit designed to transmit the first and second scanned light beams and to deflect the third light beam into a gesture detection area of the user. The optical system further includes a deflection unit, onto which the image content is projectable and which is configured to direct the projected image content and the second light beam onto an eye of a user.