Frameless Rearview Mirror Sealing via Adhesive Film
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Solution Overview
Problem
Existing rearview mirror assemblies with liquid crystal cells are prone to image impairment due to temperature fluctuations, which cause air entrainment and loss of liquid crystals, leading to increased production costs and visual defects.
Innovation Solution
A frameless mounting design with a one-piece housing and an adhesive seal between the housing and mirror assembly, eliminating the need for a clamping frame and edge sealing, ensuring a secure and sealed optical environment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a frame element is used to clamp and seal the mirror assembly in the housing, then the mirror assembly is securely fixed and sealed, but the production costs increase and the visual appearance is compromised
Solution Approach 1:
The patent merges the sealing function and the fixing function into a single adhesive film, eliminating the need for separate frame elements. The adhesive film simultaneously seals the housing gap and secures the mirror assembly, reducing component count while maintaining reliability
Solution Approach 2:
The adhesive film performs multiple functions: it seals the housing gap, fixes the mirror assembly in position, and provides structural support. This multi-functional element replaces the traditional frame element that could only perform sealing and fixing separately
2Reliability
If a frame element is used to clamp the mirror assembly, then the mirror assembly is securely held, but the visual appearance is compromised and production costs increase
Solution Approach 1:
The patent extracts the frame element from the design, removing the visual obstruction and complexity. The adhesive film provides fixation without the visible frame structure, achieving a cleaner aesthetic while maintaining secure mounting
3Reliability
If the optical cell is sealed with a circumferential seal, then the liquid crystal medium is protected, but air entrainment and liquid crystal loss occur under temperature fluctuations
Solution Approach 1:
The patent changes the sealing approach from a rigid circumferential seal to a flexible adhesive film that can accommodate thermal expansion and contraction. This parameter change in sealing methodology allows the seal to maintain effectiveness across temperature fluctuations without causing air entrainment or liquid crystal loss
4Reliability
If multiple sealing and fixing elements are used, then the mirror assembly is securely mounted and sealed, but production costs increase
Solution Approach 1:
The patent combines multiple sealing and fixing elements into a single adhesive film, reducing the number of manufacturing steps and assembly operations. This consolidation lowers production costs while maintaining mounting reliability
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 permanently flawless optical image under temperature fluctuations, reduces production costs, and enhances visual appearance by eliminating the need for additional sealing and clamping, resulting in a lightweight and cost-effective rearview mirror assembly.
Implementation Method 1
The seal is realized by an adhesive film. The adhesive achieves on the one hand a holding of the mirror assembly in the housing element and on the other hand an additional seal.
Implementation Method 2
The optical cell of the mirror assembly essentially consists of a front and rear transparent support layer, two transparent electrically conductive layers, two alignment layers and a liquid crystal layer comprising a liquid crystal medium arranged centrally between the layers.
Implementation Method 3
The liquid crystal medium of the liquid crystal layer is sealed between the alignment layers by a circumferential seal arranged at the edge. In this case, the peripheral seal is realized by means of an annular layer of adhesive material arranged at the edge. With these mirror arrangements, the reflectivity can be changed when an electric field is applied.
Data Source
Figure 1
Figure 2
Figure 2.1
AI summary
The invention relates to a rear-view mirror assembly (1) for motor vehicles, said assembly comprising a housing (3) and a mirror sub-assembly (2) held in the housing (3) and comprising a liquid-crystal cell (4), for observing the following traffic. The reflectance of the mirror sub-assembly (2) is designed to be variable by means of a control device and the liquid-crystal cell (4) has a transparent front carrier layer (5), a transparent rear carrier layer (6) and an electrically controllable liquid-crystal layer (7) between the carrier layers. The liquid-crystal layer is held in a sealed manner by means of a sealing frame (8) positioned between the carrier layers (5, 6). The object of the invention is to improve the rear-view mirror assembly (1) such that a consistently flawless optical image can be produced for the vehicle occupant as the user, that the mirror assembly is lightweight and is cost-effective in terms of production costs. To achieve this, the housing (3) is designed as one piece and permits a frameless mounting of the mirror sub-assembly (2) and a housing gap (9) remains between the housing (3) and the mirror sub-assembly (2), into which gap a seal (10) is introduced for mounting the mirror sub-assembly in the housing in a sealed manner.