Subjective Optometric Apparatus Retinal Illuminance Control
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Solution Overview
Problem
In subjective optometric apparatuses, short distances between the eye refractivity measuring unit and the target presenting unit lead to low retinal illuminance, making it difficult to perform subjective measurements in a state close to natural vision due to decreased environmental light influence.
Innovation Solution
A subjective optometric apparatus is designed with a projection optical system that includes a target presenting unit and a light emitting means surrounding the periphery, which projects target light flux onto the examinee's eye while providing surface light emission to maintain retinal illuminance, allowing for measurements in a state similar to natural vision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the distance between the eye refractivity measuring unit and the target presenting unit is shortened to save space, then device compactness is improved, but retinal illuminance decreases making it difficult to perform subjective measurement in a state close to natural vision
Solution Approach 1:
A light guide member is introduced as an intermediary component between the light source and the target presenting unit. This light guide member conducts light from the light source to illuminate the target, ensuring adequate retinal illuminance even when the distance between the eye refractivity measuring unit and target presenting unit is shortened for compactness.
Solution Approach 2:
The patent replaces the reliance on environmental light (natural vision condition) with an artificial lighting system using a light source and light guide member. This substitution ensures consistent and adequate retinal illuminance independent of the distance between components, resolving the contradiction between compactness and illuminance.
2Ease of operation
If environmental light influence is reduced in a compact design, then device portability is improved, but the natural vision state during examination deteriorates
Solution Approach 1:
The light guide member serves as a mediator that delivers controlled illumination to the target presenting unit, creating an optimal examination environment that simulates natural vision conditions regardless of the device's portability or compactness.
Solution Approach 2:
The patent changes the lighting parameters by introducing a controlled light source and light guide system, adjusting the illumination conditions to maintain natural vision state equivalence even when environmental light influence is reduced in portable designs.
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 apparatus effectively suppresses low retinal illuminance and enables subjective examinations in a state closer to natural vision by ensuring adequate illumination, reducing glare and measurement inaccuracies.
Implementation Method 1
a light guide member for conducting light from the light source
Implementation Method 2
a reflective member for reflecting light from the light source
Data Source
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AI summary
A subjective optometric apparatus includes: a projection optical system that includes a target presenting unit configured to emit a target light flux, the projection optical system being configured to project, onto an examinee's eye, the target light flux emitted from the target presenting unit; a housing configured to accommodate the projection optical system; a presentation window configured to project the target light flux onto the examinee's eye by transmitting the target light flux emitted from the projection optical system and outputting the target light flux from an inside of the housing to an outside of the housing; and an observation unit configured to observe, via the presentation window, a positional relationship between the examinee's eye and an eye refractivity measuring unit configured to change an optical property of the target light flux output from the inside of the housing to the outside of the housing.