Annular Light Guide for Uniform Macro Lens Illumination
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Solution Overview
Problem
Conventional close distance photography using macro lenses often results in uneven illumination due to the instantaneous pulse light emission from xenon lamps, requiring multiple light sources to achieve uniform lighting, which can be impractical and difficult to manage, especially when the distance between light sources is short.
Innovation Solution
A lens apparatus with an illumination system featuring a light guide member with an annular shape and multiple light sources arranged such that their normal direction coincides with the tangential direction of the light guide, ensuring uniform light distribution without increasing the number of light sources, by using conditional expressions to optimize the distance between light sources and the light guide's internal diameter and distance to the object.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If multiple light sources are arranged to uniformly illuminate the object, then illumination uniformity is improved, but the number of light sources increases
Solution Approach 1:
A light guide member is introduced as an intermediary between the light sources and the object. The light sources emit light that is guided and distributed uniformly through the light guide member, which has a specific shape and optical properties. This mediator enables uniform illumination across the object surface while using only a limited number of light sources, resolving the contradiction between illumination uniformity and the number of light sources required.
2Volume of moving object
If the distance between light sources is reduced, then the illumination apparatus size is reduced, but uniform illumination becomes difficult to achieve
Solution Approach 1:
The light guide member serves as a mediator that redistributes light from closely spaced sources. By optimizing the shape, size, and optical properties of the light guide member, light from a small number of closely positioned sources is uniformly distributed across the illumination area, enabling compact apparatus design without sacrificing illumination uniformity.
Solution Approach 2:
The invention optimizes specific parameters including the distance between light sources (DL), the internal diameter of the light guide member (D), and the distance from the light guide member to the object (WD). By carefully controlling these parameters within specific ranges, the system achieves uniform illumination while maintaining a compact size, resolving the contradiction between apparatus size and illumination quality.
3Use of energy by moving object
If light sources are disposed with light emission plane oriented in the optical axis direction, then light emission efficiency is improved, but a large number of light sources are needed for uniform illumination
Solution Approach 1:
The light guide member acts as a mediator that collects light emitted in the optical axis direction from efficient light sources and redistributes it uniformly across the illumination area. This approach maintains the high light emission efficiency of sources oriented along the optical axis while achieving uniform illumination, eliminating the need to increase the number of light sources.
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 configuration allows for uniform lighting in close distance photography using a smaller number of light sources, ensuring consistent illumination and reducing the size of the illumination apparatus while maintaining effective light distribution.
Implementation Method 1
a light guide member that causes internal reflection of light from the light sources so that the light propagates
Data Source
AI summary
A lens apparatus includes: an image pickup optical system; a holding frame that holds the image pickup optical system; and an illumination apparatus that is attached to an outer peripheral portion of an object side of the holding frame and applies light. The illumination apparatus includes light sources and a light guide member that causes internal reflection of light from the light sources so that the light propagates. The light guide member has an annular shape and has a light exit surface from which light is emitted toward an object side. A distance DL between two closest light sources in the light sources, an internal diameter D of the plurality of light guide member, and a distance WD from the light guide member to an object at a closest distance when the image pickup optical system is focused on the object at the closest distance are appropriately set respectively.