Light Pipe Assembly With Patterned Surface Elements
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Solution Overview
Problem
Light pipes used in applications like automotive lighting face challenges with uneven light distribution and securing mechanisms that can lead to accidental disconnection due to limited space, resulting in inconsistent light intensity along their length and instability.
Innovation Solution
A light pipe assembly with a pattern of surface elements and orientation features that secure the light pipe to the lamp assembly, ensuring even light distribution and alignment by varying the size and density of reflective strips and using mating portions for secure attachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If known securing structures such as clamps and epoxies are used to secure the light pipe to the lamp assembly, then the light pipe can be attached to the lamp assembly, but the light pipe may easily disconnect due to its smooth cylindrical exterior and limited space for securing structures
Solution Approach 1:
The securing structure is divided into multiple engagement features distributed around the circumference of the light pipe attachment end. These include circumferential engagement features (such as ribs or lugs) and longitudinal engagement features (such as flutes or grooves), creating multiple discrete connection points that collectively provide secure attachment without requiring a single complex securing mechanism.
Solution Approach 2:
The engagement features are designed with asymmetric geometries that provide directional securing. For example, circumferential ribs may have asymmetric cross-sections that engage with corresponding features in the housing, creating interference fits or mechanical interlocks that prevent disconnection. The asymmetric design allows secure attachment in the intended direction while facilitating assembly.
2Ease of manufacture
If the light pipe has a smooth cylindrical exterior, then the light pipe is easy to manufacture, but the light pipe can easily disconnect from the lamp assembly when known securing structures are used
Solution Approach 1:
The engagement features are pre-formed as integral parts of the light pipe during the extrusion or molding process. The circumferential ribs, flutes, and other securing features are created simultaneously with the light pipe body, eliminating the need for separate manufacturing steps or post-assembly operations. This maintains manufacturing simplicity while providing reliable connection capability.
3Illumination intensity
If surface elements are added to the light pipe to direct reflected light, then light distribution can be controlled, but the light intensity may be uneven along the length of the light pipe
Solution Approach 1:
The surface elements are designed with varying properties at different locations along the light pipe. The reflectivity, size, spacing, or orientation of surface elements changes progressively along the length of the light pipe to compensate for the decreasing light intensity. For example, surface elements near the light source may have lower reflectivity or smaller areas, while elements farther away have higher reflectivity or larger areas, creating a progressive gradient that equalizes the emitted light intensity.
4Illumination intensity
If surface elements need to be properly aligned with respect to the lamp assembly, then light can be directed in the proper direction, but alignment precision requirements increase
Solution Approach 1:
The orientation features are merged with the engagement features, forming an integrated alignment and securing system. The same structural elements that provide mechanical connection (such as ribs, flutes, or protrusions) also serve as alignment references for the surface elements. This ensures that when the light pipe is assembled to the lamp assembly, the surface elements are automatically positioned at the correct angles and orientations without requiring separate alignment operations.
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 provides a uniform light distribution along the length of the light pipe and secure attachment to the lamp assembly, preventing disconnection and enhancing light intensity consistency.
Implementation Method 1
Total internal reflection prevents the light from passing from inside the light pipe to outside of the light pipe. Total internal reflection occurs when light impinges on an interface between the light pipe and the atmosphere surrounding the light pipe at an angle that is greater than a critical angle.
Implementation Method 2
Known light pipes include a white strip or other surface element on the light pipe or inside the light pipe that reflects light impinging on the surface element.
Data Source
AI summary
A light pipe assembly includes a lamp assembly and a light pipe. The lamp assembly has a housing that holds a light source configured to emit light. The light pipe is elongated between an attachment end and an opposing distal end. The attachment end is received in the housing of the lamp assembly. The light pipe receives light emitted by the light source. Additionally, the light pipe includes surface elements that are configured to permit the light to emanate from the light pipe between the attachment and distal ends. The surface elements are arranged in a pattern that provides a predetermined distribution of light emanating from the light pipe.