Prism Assembly with Optical Film for Range Finder
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Solution Overview
Problem
Existing range finder technologies face challenges in minimizing energy loss and optimizing the design and volume of the device due to inefficiencies in light beam reflections within the prism assembly, which affect the accuracy and range of distance measurements.
Innovation Solution
A prism assembly design that incorporates a first prism, a second prism, a roof prism, and an optical multilayer film, where the second light beam undergoes two total internal reflections, with one reflection occurring from an optical total reflection film, allowing for reduced energy loss and altered beam direction, thereby enhancing measurement accuracy and range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If multiple total internal reflections are used to redirect the light beam, then the beam direction is changed, but energy loss increases
Solution Approach 1:
The prism assembly is divided into multiple prisms (first prism, second prism, third prism, fourth prism) with distinct functions. The first and second prisms handle beam direction changes through total internal reflection, while the third and fourth prisms with optical films minimize energy loss through optimized reflection paths. This segmentation allows each component to specialize in reducing specific types of energy loss.
Solution Approach 2:
Optical films (optical low reflection film, optical total reflection film) are introduced as intermediary layers on prism surfaces. These films act as mediators that enhance the total internal reflection efficiency, reducing energy loss at critical interfaces where beam direction changes occur. The optical films minimize reflection losses while maintaining the desired beam redirection functionality.
2Ease of operation
If the prism assembly uses multiple reflections to exit the beam in opposite direction, then the receiver position can be simplified, but the device volume increases
Solution Approach 1:
The patent utilizes three-dimensional spatial arrangement of four prisms configured at specific angles (45 degrees, 67.5 degrees) to achieve beam direction reversal. By optimizing the spatial configuration and using cemented interfaces between prisms, the overall device volume is minimized while maintaining the opposite direction beam exit capability that simplifies receiver positioning.
Solution Approach 2:
Multiple prism functions are merged into a single integrated prism assembly where the first, second, third, and fourth prisms work together as one unit. The cemented interfaces between prisms eliminate the need for separate mounting structures and reduce overall device volume while achieving the beam direction reversal needed for simplified receiver placement.
3Measurement precision
If optical films are added to reduce energy loss, then measurement accuracy improves, but device complexity increases
Solution Approach 1:
Optical films are applied selectively to specific prism surfaces (third surface of first prism, fifth surface of second prism, fourth surface of third prism, sixth surface of fourth prism) where total internal reflection occurs. This localized application reduces energy loss at critical interfaces without adding optical films to all surfaces, thereby minimizing device complexity while improving measurement accuracy through reduced energy loss.
4Ease of operation
If the second light beam undergoes two total internal reflections, then the beam exits in opposite direction simplifying receiver design, but energy loss increases affecting measurement range
Solution Approach 1:
Optical total reflection films are introduced as intermediary layers on the prism surfaces where the second light beam undergoes total internal reflection. These films enhance the reflection efficiency and minimize energy loss during the two reflection events, allowing the beam to exit in the opposite direction while maintaining sufficient energy for accurate distance measurement and extended measurement range.
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 design simplifies the range finder's structure, reduces its volume, and improves the accuracy and range of distance measurements by minimizing energy loss and optimizing light beam propagation within the prism assembly.
Implementation Method 1
the optical multilayer film reflects the first light beam but allows the second light beam to pass through
Implementation Method 2
the second light beam is incident on the fifth surface of the second prism and totally reflected by the sixth surface so that a propagation direction thereof is changed
Data Source
AI summary
A prism assembly includes a first prism, a second prism, a roof prism and an optical multilayer film. The first prism includes a first, a second and a third surface. The second prism includes a fourth, a fifth and a sixth surface. The fifth surface faces the third surface. The roof prism includes a seventh, an eighth and a ridge surface. The seventh surface faces the second surface. The optical multilayer film is disposed between the fifth surface and the third surface. A first light beam and a second light beam entering the first prism are totally reflected from the second surface to the optical multilayer film which reflects the first light beam but allows the second light beam to pass through. The second light beam enters the second prism, is totally reflected on the sixth surface, and exits from the fourth surface of the second prism.