Vision Testing System Screen Luminance Calibration
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Solution Overview
Problem
Existing vision testing systems face inaccuracies in subjective refraction determination due to non-linear response of discrete electronic components in adjustment devices, leading to deviations between objectively and subjectively determined refraction values under changing lighting conditions, particularly in mesopic or scotopic lighting.
Innovation Solution
A vision testing system with a backlit display device featuring an optoelectronic sensor to measure and adjust screen luminance proportionally to ambient luminance, ensuring consistent display conditions, and an additional sensor to measure ambient luminance independently, allowing for precise regulation of screen luminance and ambient luminance to maintain linear adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If discrete electronic components (optoelectronic sensor) are used to adjust screen luminance to ambient luminance, then the screen luminance can be adapted to different lighting conditions, but the non-linear response characteristic of these components causes non-proportional adjustment that falsifies refraction determination results
Solution Approach 1:
The patent transforms the non-linear adjustment characteristic into a measurable parameter by introducing a calibration function that maps the non-linear sensor response to the desired linear screen luminance adjustment. The control unit stores calibration data that compensates for the non-linear behavior, allowing the system to maintain measurement precision while preserving adaptability to different lighting conditions.
2Illumination intensity
If the screen luminance is reduced to simulate twilight or night vision conditions, then the desired vision conditions are achieved, but the camera device cannot measure the eyes due to insufficient lighting
Solution Approach 1:
The patent separates the lighting functions into different spectral domains: visible light for screen display and infrared light for eye measurement. The system uses separate light sources (visible light for the screen, infrared LEDs for illumination) and separate sensors (camera for visible light, infrared sensor for eye measurement), allowing independent optimization of each function without interference.
Solution Approach 2:
The patent introduces an infrared illumination system as an intermediary to enable eye measurement under low visible light conditions. The infrared light sources illuminate the eyes without affecting the visible light display, and the infrared sensor detects eye reflections in the infrared spectrum, acting as a mediator that bridges the gap between low visible light conditions and measurement requirements.
3Illumination intensity
If the room is darkened to create mesopic or scotopic lighting conditions for subjective refraction testing, then the desired lighting conditions are achieved, but objective refraction measurement with camera device becomes impossible
Solution Approach 1:
The patent divides the measurement system into separate channels: a visible light channel for subjective refraction testing under controlled ambient luminance conditions, and an infrared channel for objective refraction measurement. The infrared illumination and detection systems operate independently of the visible light environment, allowing objective measurements to be performed reliably even when the room is darkened for mesopic or scotopic vision testing.
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 solution enables more precise eye tests by maintaining constant display conditions, reducing errors in refraction determination across varying lighting conditions, and allowing for accurate comparison of objective and subjective refraction values.
Implementation Method 1
the adjustment device has a measuring device with which a screen luminance of the screen can be measured. In particular, the measuring device has an optoelectronic sensor with which the screen luminance can be measured
Implementation Method 2
the measuring device has a further optoelectronic sensor with which an ambient luminance can be measured
Implementation Method 3
the screen luminance can be adjusted to an ambient luminance, wherein the screen luminance is adjusted proportionally as a function of the ambient luminance
Data Source
Figure 1~2
AI summary
The invention relates to a vision testing system (10) and a method for checking the eyes of a test subject, comprising a display device (11, 12, 13) with which vision test symbols can be visualized for at least one eye of the test subject, comprising a control unit (14) for controlling the display device, wherein the display device comprises a backlit screen (19, 30, 35), wherein the screen has an adjustment device for adjusting a screen luminance of the screen to an ambient luminance, wherein the adjustment device has a measuring device for measuring the screen luminance.