Optotype Display Luminance Calibration for Visual Acuity Testing
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Solution Overview
Problem
Existing optotype presenting apparatuses have varying background luminance levels, leading to compatibility issues and unreliable visual acuity test results when different devices are used together, as they often fall outside the standard range of 80 to 320 cd/m2, making it difficult to adjust and maintain consistent luminance across multiple devices.
Innovation Solution
An optotype presenting apparatus with a light intensity changing device, a background luminance selecting device, and a correction device that uses measured luminance data to adjust backlight intensity, ensuring the luminance falls within the standard range by allowing multiple preset levels and automatic correction, enabling easy adjustment and compatibility among multiple devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the background luminance is adjusted by changing backlight voltage, then the luminance can be changed, but the luminance largely varies among apparatuses even by the same adjustment value, resulting in unreliable visual acuity test results
Solution Approach 1:
The patent applies parameter changes by establishing a relationship between backlight voltage and background luminance through actual measurement. Instead of using fixed voltage adjustment values, the system measures the actual luminance produced by each voltage level and uses this measured data to determine appropriate voltage settings that achieve the target luminance range (80-320 cd/m2), thereby ensuring reliable and consistent visual acuity test results across different apparatuses.
2Adaptability or versatility
If multiple optotype presenting apparatuses are adopted in the same place, then more functionality is available, but the background luminances of those apparatuses cannot be adjusted to the same luminance level, making it hard to provide compatibility
Solution Approach 1:
The patent enables easy luminance matching across multiple apparatuses by measuring the actual background luminance at each voltage level and determining the specific voltage that produces the desired luminance. This measured parameter approach allows different apparatuses to be adjusted to the same luminance level, ensuring compatibility and ease of operation while maintaining the functionality of having multiple apparatuses.
3Adaptability or versatility
If the background luminance is adjusted to match different apparatuses, then compatibility is improved, but the adjustment process becomes complex and time-consuming
Solution Approach 1:
The patent applies preliminary action by pre-measuring and storing the relationship between backlight voltage and background luminance for each apparatus. This calibration data is saved in the apparatus memory, allowing the system to quickly retrieve and apply the appropriate voltage setting for the desired luminance level without requiring time-consuming manual adjustment each time the apparatus is used or when matching multiple apparatuses.
Solution Approach 2:
The patent uses feedback by measuring the actual background luminance produced by each voltage level and using this measured information to determine the correct voltage setting. This closed-loop approach ensures that the apparatus reaches the target luminance level (80-320 cd/m2) accurately and efficiently, reducing adjustment time while maintaining compatibility.
Data Source
AI summary
An optotype presenting apparatus which presents an optotype for visual acuity test, the apparatus comprises: a display that is illuminated by a backlight and includes a light intensity changing device which changes backlight intensity; a background luminance selecting device which selects background luminance of the optotype among a plurality of preset levels, in which background luminance at each level corresponds to standard light intensity changing data in a changeable range determined by the light intensity changing device; and a correction device which corrects the standard light intensity changing data in the background luminance selecting device, the correction device including: an input device which inputs the background luminance measured by an illuminance meter, the measured background luminance being background luminance obtained when the light intensity changing device is operated based on the preset light intensity changing data; and a calculation device which determines correction light intensity changing data by comparing the background luminance input by the input device and the preset light intensity changing data.