Retinal Implant Light Projector with Pulse Width Modulation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for projecting patterns onto modified retinal areas with retinal implants lack the ability to provide grayscale vision, and safety concerns related to irradiation duty cycles are not adequately addressed.
Innovation Solution
A method and device that modulate a pulsed input light beam into a pattern of modulated pulsed sub-beams, allowing for individual pulse width modulation of each sub-beam to control irradiation duration and achieve grayscale perception, while ensuring safe duty cycles to prevent retinal damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a pulsed light beam is projected onto the retinal area with constant irradiation for each pulse, then the patient can sense light/dark contrast, but the patient is merely able to sense a single light/dark contrast without grayscale perception
Solution Approach 1:
The light beam is divided into multiple independently controllable sub-beams corresponding to different regions of the retinal implant. Each sub-beam can be individually modulated in duration and intensity, allowing different zones of the retina to receive different irradiation patterns. This segmentation enables grayscale perception across the visual field while maintaining system manageability.
Solution Approach 2:
The system dynamically adjusts the irradiation parameters (duration, intensity, timing) of each sub-beam based on the desired grayscale pattern. By varying these parameters in real-time according to the image information being displayed, the system creates perceptible grayscale differences without requiring complex hardware modifications.
2Illumination intensity
If the projector device irradiates the retina with high optical irradiance, then the brightness perception is improved, but the average optical irradiance may reach safety threshold causing retinal damage
Solution Approach 1:
The system uses periodic pulsed irradiation instead of continuous illumination. By delivering light in controlled pulses with appropriate duty cycles, the peak irradiance can be sufficiently high for good brightness perception, while the average irradiance remains below safety thresholds. The intervals between pulses allow retinal cooling and prevent thermal damage.
Solution Approach 2:
The system dynamically changes irradiation parameters including pulse duration, frequency, and duty cycle to optimize both brightness perception and safety. By adjusting these parameters based on the specific display content and viewing conditions, the system maintains high perceived brightness while ensuring the average optical irradiance stays within safe limits for retinal tissue.
3Reliability
If the projector device ensures safe duty cycle by shutting down between pulses, then retinal safety is improved, but the power consumption and irradiation efficiency decrease
Solution Approach 1:
Different regions of the retinal implant receive different irradiation patterns tailored to their specific requirements. Some zones may receive longer or more intense irradiation while others receive shorter pulses, allowing the system to minimize total energy consumption while maintaining safety margins. This localized optimization reduces overall power requirements compared to uniform irradiation of the entire retinal area.
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
Enables patients with retinal implants to perceive grayscale images, improving orientation and visual faculty, while ensuring safe and efficient operation by controlling irradiation duty cycles and reducing power consumption.
Implementation Method 1
Each pixel has one or several photodiodes that capture the light delivered from a visual processor and converts it into electrical current for stimulation
Implementation Method 2
When the gaze direction is such that some part of the implants is illuminated by part of the pattern, the implant converts that part of the signal to electrical current that stimulates the retina accordingly
Data Source
AI summary
The present invention pertains to a method for projecting a pattern of interest (6) on a modified retinal area (5) of a human eye, comprising the steps of providing a pulsed input light beam (20), modulation and dividing the pulsed input light beam (20) into a pulsed modulated light pattern of modulated pulsed sub-beams (40) based on a pattern of interest (6), wherein the modulated light pattern forms a pulsed output beam (4) reflecting the pattern of interest (6), wherein performing an individual pulse width modulation of a modulation duty cycle (32) of the modulated individual sub-beams (40) forming the output beam (4), and to correspondingly adapted device.