Illumination Device Snap-Fit Light Guide Plate
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Solution Overview
Problem
Existing illumination devices for on-vehicle control panels face challenges in reliably fixing light guide plates without adhesives, leading to rattling and noise due to improper snap-fitting dimensions.
Innovation Solution
The illumination device employs retaining and push-up projections on the tubular case to elastically hold the light guide plate, preventing rattling and eliminating the need for adhesives by bending the plate into place.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the distance between the stepped portion and projections is set to be sufficiently larger than the thickness of the light guide plate to enable snap-fitting, then the control knob and tubular case can be properly assembled, but the light guide plate rattles between the stepped portion and projections causing abnormal noise
Solution Approach 1:
The patent introduces a light guide plate as an intermediary component between the stepped portion and projections. The light guide plate fills the gap created by the snap-fitting structure, preventing rattling while maintaining the assembly ease. The light guide plate is positioned within the space between the stepped portion and projections, serving as a mediator that eliminates the harmful rattling noise without compromising the snap-fitting assembly process.
2Reliability
If adhesive is used to fix the light guide plate, then the light guide plate can be securely held, but the application process becomes troublesome and adhesive strength declines with time
Solution Approach 1:
The patent replaces the chemical bonding mechanism (adhesive) with a mechanical holding system consisting of a tubular case with integrated holding portions. The holding portions mechanically engage with the light guide plate through snap-fitting, eliminating the need for adhesive application processes. This mechanical system provides reliable holding strength without the drawbacks of adhesive degradation over time or complex application procedures.
Solution Approach 2:
The tubular case is designed with self-contained holding portions that automatically secure the light guide plate during assembly. The holding portions are integrally formed with the tubular case, allowing the structure to self-secure the light guide plate without requiring external adhesive materials or additional fastening components. The snap-fitting mechanism automatically engages when the light guide plate is inserted, providing reliable fixation through the inherent mechanical design.
3Reliability
If adhesive is used to fix the light guide plate, then the light guide plate can be held in position, but the adhesive strength declines with time
Solution Approach 1:
The patent replaces the chemical bonding mechanism (adhesive) with a mechanical holding system consisting of a tubular case with integrated holding portions. The holding portions mechanically engage with the light guide plate through snap-fitting, eliminating the need for adhesive application processes. This mechanical system provides reliable holding strength without the drawbacks of adhesive degradation over time or complex application procedures.
Solution Approach 2:
The tubular case is designed with self-contained holding portions that automatically secure the light guide plate during assembly. The holding portions are integrally formed with the tubular case, allowing the structure to self-secure the light guide plate without requiring external adhesive materials or additional fastening components. The snap-fitting mechanism automatically engages when the light guide plate is inserted, providing reliable fixation through the inherent mechanical design.
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 allows for easy and secure mounting of the light guide plate without adhesives, preventing rattling and ensuring a reliable holding structure, enhancing the durability and functionality of the illumination device.
Implementation Method 1
the light guide plate is held inside the tubular case while being bent upwardly... The light guide plate is held while being elastically urged against the retaining projections and the push-up projections by a bending force
Data Source
AI summary
An illumination device includes a control knob having a display portion, a tubular case combined with a back side of the control knob, a light guide plate attached to seal an upper opening of the tubular case, and LEDs disposed at a lower opening of the tubular case. Light emitted from the LEDs is applied to the display portion through the light guide plate. A plurality of retaining projections and a plurality of push-up projections are provided on an inner surface of the tubular case adjacent to the upper opening. An upper surface of an outer edge of the light guide plate is retained by lower ends of the retaining projections, and a lower surface of the outer edge is pushed up by upper ends of the push-up projections so that the light guide plate is held inside the tubular case while being bent upwardly.