Off-Axis Prism Module for Compact Binoculars
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Solution Overview
Problem
The existing Schmidt-Pechan prism assembly in rangefinder binoculars becomes large and costly when off-axis, necessitating a new design for a compact structure that reduces light path attenuation and promotes brightness.
Innovation Solution
The proposed optical device features a prism module with a first and second prism, where the first light enters and exits through specific surfaces, and the second light is generated internally with minimal path length, using films to separate visible and invisible light paths, and the module is arranged off-axis for compactness and reduced volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a Schmidt-Pechan prism assembly is used in off-axis arrangement, then the binoculars can achieve compact structure, but the volume of the prism assembly becomes large and the producing cost increases
Solution Approach 1:
The patent divides the traditional single Schmidt-Pechan prism assembly into two separate prisms: a first prism for reflecting visible light and a second prism for reflecting invisible light. This segmentation allows each prism to be optimized independently, reducing the overall volume while maintaining the off-axis arrangement benefits for compact binocular structure.
Solution Approach 2:
The patent applies different optical properties to different parts of the system by using a wavelength-selective film that selectively reflects invisible light while allowing visible light to pass through. This local quality differentiation enables the two prisms to work independently for different wavelength ranges, reducing the volume required compared to a single large prism assembly.
2Reliability
If the light path in the displaying system is long, then the optical device can achieve complete light reflection, but the attenuation of light energy increases and the brightness decreases
Solution Approach 1:
The patent extracts the invisible light reflection function into a separate second prism with its own independent light path. This allows the visible light path in the displaying system to be shortened, reducing attenuation and improving brightness, while the invisible light path handles the wavelength-specific reflection requirements separately.
Solution Approach 2:
The wavelength-selective film acts as an intermediary element that separates visible and invisible light paths. It allows visible light to pass through to the displaying system with a shorter, less attenuating path, while directing invisible light to the second prism for complete reflection, thus resolving the contradiction between path length and reflection completeness.
3Device complexity
If the light emitter and display are disposed close together, then the device structure is simplified, but light interference occurs between the two components
Solution Approach 1:
The wavelength-selective film serves as an intermediary that spatially and spectrally separates the light paths of the emitter and display. It allows the components to be disposed close together structurally while preventing light interference by directing different wavelengths into separate optical paths - visible light to the display and invisible light from the emitter.
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 results in a compact optical device with reduced light path attenuation, enhanced brightness, and effective light interference avoidance, suitable for large aperture binoculars.
Implementation Method 1
is sequentially reflected on the second surface, the third surface and the first surface
Implementation Method 2
the film is configured to reflect the first light
Implementation Method 3
is sequentially reflected on the eighth surface and the seventh surface
Data Source
AI summary
An optical device and the prism module thereof are provided. The prism module includes a first prism, a second prism, and a third prism. The second prism is disposed beside the first prism. The third prism is adhered to the second prism. First light enters the first prism, is reflected plural times in the first prism, enters the second prism, and is emitted from the second prism. Second light enters the second prism, is reflected plural times in the second prism, and is emitted from the second prism. Third light sequentially passes through the third prism and the second prism, enters the first prism, is reflected plural times in the first prism, and is emitted from the first prism.