Mitsumi miniature mechanical

Mitsumi miniature mechanical
Manufacturer	Mitsumi
Switch type	Linear, tactile, clicky
Sense method	Metal leaf
Keycap mount	Mitsumi mount, Cherry MX mount, Alps mount
Switch mount	Plate mount/PCB mount

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Mitsumi miniature mechanical is a miniature, low-profile keyboard switch from Mitsumi.

Description

Mitsumi miniature mechanical switches are not only low-profile, but also very shallow front-to-back. The total size (not including legs or slider) is approximately 15.6 mm wide by 9.5 mm deep and 9.2 mm tall. Height above the plate is around 5.4 mm without the slider, and the total height including slider is around 13.5 mm. Total travel appears to be 4.3 to 4.5 mm. The switch has a metal top that is secured on either side by ramps on the outside of the shell and on the inside of the plate retention clips, making the switch extremely hard to open. The metal top bears either the old ("ミツミ": mi-tsu-mi) or new Mitsumi logo stamped into the side. The slider can be Mitsumi mount^[1], Cherry MX mount^[2] or, in rare cases, Alps mount.^[3]

The switches are designed to be plate-mounted, but with six legs, they appear to be designed to support PCB mounting also, especially considering their form factor. In many cases, these switches were indeed PCB mounted.^[4]^[1] The front left and back left legs are electrically connected, as are the front right and back right legs. The switch contacts connect the left side legs to the right side legs. The left and right centre legs are part of the metal lid and are therefore connected to each other, forming a circuit jumper.

The design of the contacts varies, but all switches examined to date follow the same overall design. A vertical plastic frame holds a thin sheet of metal on one side which bears a raised, gold-plated prism. A flexible copper strip is mounted into the opposite side, which reaches across the space within the frame. The copper strip is held away from the slider by either folds in the metal or a small plastic follower inserted through the strip. When the slider is depressed, the follower or extended section of the strip are released into a recess in the slider, and fingers at the end of this strip touch the stationary contact.

The return spring can be mounted either vertically (as with typical switches)^[1] or slung horizontally under the slider.^[5] The latter design provides tactility using only a single spring; the base nub in these switches (that normally locates a vertical spring) is modified with a lateral groove for the spring to slide over. As the slider in a tactile switch is depressed, the lateral spring is stretched over the base nub; as the force on the spring rises, it will suddenly give, generating tactility.

A batch of yellow tactile switches purchased by Devlin have been confirmed to be highly tactile, while most people report the switches to be only lightly tactile.^{[Citation needed]}

The construction of the linear and tactile versions are well documented; a clicky version also exists, but thus far, the internals are not known.

The switch case is reported to break sometimes if a keycap is removed without due care.^{[Citation needed]}