Prism Module Design for Rangefinder Volume Reduction
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Solution Overview
Problem
Conventional rangefinders with Schmidt-Pechan prism systems suffer from light leakage, large dimensions, reduced image brightness due to multi-reflections, and energy attenuation from overlapping optical diameters of light beams, leading to compromised image quality and increased volume.
Innovation Solution
A new prism module design featuring a roof pentaprism and a half-penta prism with strategically placed coatings to reflect specific light beams while allowing others to pass through, reducing volume, minimizing light leakage, and enhancing image brightness by avoiding overlapping optical diameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a Schmidt-Pechan prism system is used, then the optical path can be folded, but light leakage occurs and image quality deteriorates
Solution Approach 1:
The patent divides the traditional Schmidt-Pechan prism system into separate functional components: a roof prism for image erection and a pentaprism for optical path folding. This segmentation allows each prism to be optimized independently, eliminating light leakage issues while maintaining the compact folded optical path structure.
Solution Approach 2:
The patent extracts the light leakage problem from the integrated Schmidt-Pechan system by separating the image erection function (roof prism) from the optical path folding function (pentaprism). This extraction eliminates the harmful light leakage effect while preserving the beneficial compact structure.
2Ease of manufacture
If the prism module dimensions are increased to accommodate non-coaxial objective and ocular modules, then manufacturing flexibility improves, but the overall device volume increases
Solution Approach 1:
The patent utilizes three-dimensional spatial arrangement of the separated prisms to achieve non-coaxial objective and ocular module alignment. By positioning the roof prism and pentaprism at different spatial locations and orientations, the design accommodates manufacturing flexibility while maintaining a compact overall volume through efficient use of available space.
3Adaptability or versatility
If multiple light beams pass through the prism module, then functional versatility improves, but brightness is reduced due to multi-reflections
Solution Approach 1:
The patent applies different surface treatments to different parts of the prisms: the roof prism surfaces are coated with high-reflectivity coatings to maintain brightness for image beams, while the pentaprism uses total internal reflection surfaces for laser beam handling. This local quality differentiation allows multiple light beams to pass through with minimal brightness loss for each specific function.
4Volume of moving object
If light emitter and display unit are arranged with overlapping optical diameters, then device compactness improves, but energy is attenuated due to interference
Solution Approach 1:
The patent introduces the pentaprism as an intermediary optical element that spatially separates the laser beam path from the display unit optical path. This intermediary arrangement allows the light emitter and display unit to be positioned close together (maintaining compactness) while preventing their optical diameters from overlapping, thus avoiding energy attenuation and interference.
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 new prism module reduces the volume of the rangefinder, improves image quality, and maintains high brightness and energy efficiency of light beams by eliminating light leakage and overlapping optical diameters, allowing for better performance without the need for a Schmidt-Pechan system.
Implementation Method 1
The first coating is disposed between the third surface and the seventh surface. A first light beam is emitted by an object, enters the first prism through the first surface, is sequentially reflected on the second surface and the third surface, and leaves from the fourth surface of the first prism. The first light beam is reflected towards the fourth surface by the first coating when reflected on the third surface.
Implementation Method 2
A first light beam is emitted by an object, enters the first prism through the first surface, is sequentially reflected on the second surface and the third surface, and leaves from the fourth surface of the first prism.
Data Source
AI summary
An optical device includes an objective module, a prism module and an ocular module. The prism module includes a first prism, a second prism and a first coating. The prism module is disposed between the objective module and the ocular module. A first light beam emitted by an object sequentially passes through the objective module, the prism module and the ocular module. Central axes of the objective module and the ocular module are in parallel without overlapping.