Vehicle Lighting Lens Body Using Total Internal Reflection
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Solution Overview
Problem
Conventional lens bodies for vehicle lighting fixtures with metal deposition-based reflection surfaces suffer from low light use efficiency and increased costs due to reflection loss and durability issues.
Innovation Solution
A lens body configuration that omits metal deposition by using an incident surface with a tilted normal line to ensure light is refracted at a critical angle, allowing for internal reflection and emission through a convex lens surface, forming a predetermined light distribution pattern with a cutoff line, including a first reflection surface that condenses light near the focal point and a second reflection surface that extends backward to enhance light collection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If metal deposition is applied to form reflection surfaces, then reflection capability is improved, but light use efficiency deteriorates due to reflection loss
Solution Approach 1:
The patent replaces metal deposition-based reflection surfaces with a geometric optics approach using a tilted incident surface. The normal line of the incident surface is tilted by a predetermined angle (e.g., 45 degrees) relative to the optical axis, enabling light to enter the lens body and undergo total internal reflection at the first reflection surface without requiring metallic reflective coatings. This substitution eliminates the inherent reflection losses associated with metal deposits while maintaining effective light reflection capability through precise angular geometry.
2Illumination intensity
If metal deposition is applied to form reflection surfaces, then reflection capability is improved, but manufacturing cost increases
Solution Approach 1:
The patent eliminates the need for metal deposition facilities, processes, and materials by using a tilted incident surface geometry that enables total internal reflection. The reflection surfaces are formed as integral parts of the lens body through molding or machining, removing the requirement for separate metal deposition steps and associated manufacturing infrastructure, thereby significantly reducing manufacturing costs.
3Illumination intensity
If metal deposition is applied to form reflection surfaces, then reflection capability is improved, but durability deteriorates
Solution Approach 1:
The patent replaces the fragile metal deposition layers with a robust geometric structure where the tilted incident surface and reflection surfaces are formed as integral parts of the lens body. This eliminates the risk of metal deposition peeling, cracking, or degrading over time, providing a permanent and durable solution that maintains its optical performance throughout the product lifecycle.
4Loss of energy
If light is refracted at a critical angle through a tilted incident surface, then light use efficiency is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent specifies a predetermined tilt angle (e.g., 45 degrees) for the incident surface normal line relative to the optical axis. This parameter is optimized to achieve total internal reflection and efficient light guidance while being manufacturable with conventional precision. The predetermined angle provides a clear design target that balances optical performance with manufacturing feasibility, avoiding excessively tight tolerances that would make production prohibitively difficult.
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 suppresses reflection loss and reduces costs by optimizing light use efficiency, particularly near the cutoff line, and can form various light distribution patterns like low beam or fog lamp patterns with improved brightness and light collection.
Implementation Method 1
an incident surface having a normal line tilted by a predetermined angle with respect to a reference axis orthogonal to the optical axis and included in a plane containing the normal line and the optical axis where light within a predetermined angular range with respect to the optical axis is refracted in a condensing direction and enters the interior of the lens body
Implementation Method 2
the normal line of the incident surface is tilted with respect to the reference axis so that an incident angle of the light entering the interior of the lens body to the first reflection surface is greater than or equal to a critical angle
Data Source
AI summary
A lens body includes: an incident surface where light entering within a predetermined angular range with respect to an optical axis of the light source is refracted in a condensing direction; a first reflection surface that internally reflects the light; and a second reflection surface that internally reflects part of the reflected light from the first reflection surface. The lens body includes an emission surface of a convex lens surface. The second reflection surface extends backward from near a focal point of the emission surface. Light obtained by blocking part of the light internally reflected by the first reflection surface with a front edge of the second reflection surface, and the light internally reflected by the second reflection surface are emitted from the emission surface to from a predetermined light distribution pattern including a cutoff line defined by the second reflection surface at the upper edge.