Heated Lens Unit FPC Layout to Prevent Crushed Heater Connections
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing lens units face issues of short circuits due to the crushing of connection portions between electrodes and wiring members, particularly when a conductive film or flexible printed circuit board is sandwiched between lenses, leading to nonconformities and reduced optical performance.
Innovation Solution
The lens unit design includes a transparent conductive film on the first lens, with electrodes on protruding portions of a flexible printed circuit board that avoid interference with other components, using a blackened film to reduce ghosting and a protective film to prevent oxidation, and notch portions to prevent warping and short-circuiting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a flexible printed circuit board is used to feed power to a conductive film heater, then the heater can be effectively powered, but the connection portion between the electrode and wiring member may be crushed between the lens and lens barrel, causing short circuits
Solution Approach 1:
The electrode is extended in the radial direction to form a protruding portion, changing the spatial arrangement from a flat connection to a three-dimensional configuration. This dimensional change allows the electrode to extend beyond the plane where crushing occurs, ensuring reliable electrical connection while avoiding the harmful effect of being sandwiched between components.
2Object-affected harmful factors
If a conductive film is disposed on the lens surface as a heater, then condensation can be suppressed, but the connection portion may be sandwiched and crushed, leading to short circuits
Solution Approach 1:
The electrode is designed with a protruding portion that extends radially outward, moving the critical connection area to a different spatial dimension. This allows the heater function to be maintained on the lens surface while the electrical connection is positioned in a location that is not subject to crushing forces during assembly.
3Ease of manufacture
If the connection portion is positioned in the conventional flat arrangement, then assembly is simple, but the connection portion is pressed and crushed between components
Solution Approach 1:
The electrode protrudes radially outward from the flat surface, creating a three-dimensional connection structure. This maintains ease of assembly since the protruding shape is formed during manufacturing, while simultaneously protecting the electrical connection from being crushed between components during the assembly process.
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 effectively suppresses condensation and optical performance degradation by direct heating of the first lens, minimizing the risk of short circuits and maintaining optical clarity.
Implementation Method 1
a heater is disposed inside the lens unit in order to suppress condensation inside the lens unit when the lens unit is used outdoors. For example, Japanese Patent No. 4252959 describes the use of a conductive film such as an ITO film formed on the lens surface as a heater.
Implementation Method 2
a blackened film on the flange surface minimizes ghosting and optical performance degradation
Data Source
AI summary
A lens unit 1 includes a plurality of lenses aligned in a row along an optical axis L and a lens holder 2. A transparent conductive film 16, which functions as a heater, is disposed on an image-side lens surface 12 of the first lens L1 disposed the closest to an object side La. A flexible printed circuit board 8 that feeds power to the transparent conductive film 16 includes a flat surface portion 81 along an image-side flange surface 13 surrounding an outer peripheral side of the image-side lens surface 12, an extension portion 82 extending to an outer side in a radial direction, and a protruding portion 83 projecting to the outer side in the radial direction from the flat surface portion 81. The protruding portion 83 includes a first electrode 84A and a second electrode 84B electrically connected to the transparent conductive film 16.