Various types of rearview mirrors can be used in connection with vehicle interiors. In general, rearview mirrors are mounted adjacent the windshield either by attachment with the windshield or to an internal component adjacent the headliner. Such attachment is, for example, achieved by a mounting that couples with an actuation mechanism internal to the mirror housing. A substrate is affixed with the mirror housing and is generally configured to present an image of the view to the rear of the vehicle and, accordingly, may be adjustable by movement of the housing about the mounting structure.
In the case of a standard rearview mirror, the substrate is often a prism-type mirror that provides for a viewing angle at which the substrate reflects the rearward view of the mirror with a reduced luminosity to provide a dimming effect useful when driving at night, for example. In such an embodiment, the dimmed viewing angle for the substrate may be at a predetermined angle upward (i.e. toward the headliner) relative to the “normal” viewing angle. To achieve such positioning, rearview mirrors include various types of actuation mechanisms to provide for user control in repositioning of the substrate. Such movement can be achieved by manipulation of a lever, which can cause the actuation mechanism to move between stable positions, thereby causing movement of the substrate through a predetermined angle relative to the mounting structure that appropriately positions the substrate in a corresponding viewing position. Further, the actuation mechanism can couple with the mounting to allow general adjustment of the housing and substrate with respect to the driver for viewing of the image viewable on the substrate. In this manner, the actuation mechanism can allow the substrate to toggle between the stable viewing positions without changing the positions themselves such that the substrate provides generally the same view in the night mode as has been selected for the standard mode.
Some existing actuation mechanisms achieve movement between the above-referenced stable positions by way of a resiliently deformable spring plate. In general, such spring plates include a bent section to provide an area of flexation that accommodates movement of components within the actuation mechanism. The spring force achieved by such flexation can urge the actuation mechanism to one of the stable positions. These types of structures, while providing biasing forces toward both stable positions, may provide force in the directions toward and away from the stable positions in varying amounts. In particular, the shape of the bent portion or portions may serve to secure the mechanism in one of the stable positions, including making it less susceptible to unintended movement out of such position by a force applied on the mirror housing, for example. However, in the opposite position, the mechanism may be susceptible, depending on the particular spring force and other internal forces, to inadvertent movement out of the stable position, which may be caused by a user adjusting the position of the mirror by grasping and moving the housing. In the case of a standard prism mirror, such inadvertent actuation may be inconvenient. Accordingly, further advances may be desired.