Low-Bulk Optical Collimator for Small Illumination Spots
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Solution Overview
Problem
Current surgical lighting devices face challenges in creating small illumination spots with standard collimators, which are bulky and costly due to increased height and diameter requirements, and suffer from Fresnel reflection losses causing interfering halos on the operative field.
Innovation Solution
A solid optical collimator with a truncated cap and frustoconical recess design, featuring a through hole and an annular screen for light control, made of injection-molded poly(methyl methacrylate) plastic, allowing for a compact and lightweight structure that focuses light onto a small illumination spot without halos.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a standard collimator is used to form a small illumination spot, then the illumination spot size is reduced, but the collimator height and diameter must be increased making it bulky
Solution Approach 1:
The patent inverts the traditional collimator structure by placing the light source at the large base instead of the small base, and positioning the lens at the small base end. This inversion allows the collimator to achieve compact dimensions while forming small illumination spots, as the light propagation path is optimized in the reverse direction compared to conventional designs
Solution Approach 2:
The patent modifies key geometric parameters of the collimator including the cone angle, base dimensions, and lens position to optimize the illumination spot size. By carefully adjusting these parameters, the collimator achieves compact size while maintaining the capability to form small illumination spots on the operative field
2Illumination intensity
If a standard collimator is used to form a small illumination spot, then the illumination spot size is reduced, but the manufacturing cost is increased due to longer injection-molding time
Solution Approach 1:
The patent optimizes the collimator thickness parameter to enable the use of thinner plastic material while maintaining structural integrity and optical performance. This parameter change reduces the injection-molding time and associated manufacturing costs, making the production of compact collimators economically viable
3Illumination intensity
If a standard collimator is used, then light is reflected by Fresnel reflection loss creating interfering halos on the operative field
Solution Approach 1:
The patent addresses Fresnel reflection losses by optimizing the internal surface geometry of the collimator and the positioning of the lens to redirect reflected light into useful optical paths. This converts the potentially harmful Fresnel reflections into beneficial light contributions that enhance illumination quality without creating interfering halos on the operative field
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 solution enables the formation of small illumination spots with reduced collimator height and manufacturing costs, while eliminating interfering halos, resulting in a more compact and efficient surgical lighting device.
Implementation Method 1
a truncated cap having an inside surface operating in total internal reflection and having a small base opening into a frustoconical through recess
Implementation Method 2
having a refractive large base such that incident light emitted by the light source is guided in totality by the inside surface towards the large base of the cap
Data Source
AI summary
A lighting device comprises a solid optical collimator (6′), the collimator comprises a truncated cap having an inside surface (10′) operating in total internal reflection and having a small base opening into a frustoconical through recess that is coaxial with the cap and at the centre of which a light source (8′) is placed, and having a refractive large base such that incident light emitted by the light source is guided in totality by the inside surface towards the large base of the cap. The recess of the collimator is disposed in the cap in such a manner as to have a small base open and coinciding with the small base of the cap.