Mechanical keyboards have enjoyed something of a renaissance recently. Much of that revival can be attributed to Cherry's MX mechanical key switches, which have cropped up in all manners of clicky gaming keyboards—as well as more austere offerings designed for hardcore typists.
The Cherry MX switches aren't the only mechanical ones around, though. For many years, discerning users with ample budgets have splurged on Topre keyboards—high-priced, made-in-Japan offerings that feature a unique type of mechanical key switch made up of metal springs and rubber domes. Where most Cherry MX-based keyboards rarely venture far from the $100 mark, Topre offerings cost upward of $230.
Correction: they used to cost upward of $230.
Earlier this year, Topre introduced the Type Heaven, a keyboard that brings the firm's unique spring-and-rubber switches to a no-frills package with a less terrifying price tag. Right now, you can find the Type Heaven on sale for $150 at Amazon—not a huge step up from, say, the Cherry MX-based Das Keyboard Model S, which sells for $139.
Topre had to cut a few corners to reach the lower price point, of course. The Type Heaven is manufactured in China rather than Japan, and it lacks some of the bells and whistles of its pricier brethren, such as distributed key switch weighting and the ability to re-map keys with hardware DIP switches. Also, the Type Heaven's key caps are made of a different type of plastic, and they're laser etched rather than printed using more durable dye sublimination.
Those sacrifices are small, though, and they've helped to make the Type Heaven an interesting—and competitive—alternative to high-end Cherry MX keyboards. The folks at EliteKeyboards.com were kind enough to send us one to test, and I've spent the past little while banging away on it.
Rubber domes with a twist
Before we talk more about the Type Heaven, we should first explain what makes it special: those fancy Topre switches. The proper term for them is "electrostatic capacitive switches," and their operation is different from that of other mechanical switches like the Cherry MX series or even IBM's buckling springs.
According to Topre's original patent application, the electrostatic capacitive switch design combines a conical spring with a rubber dome, and it's actuated capacitively, without requiring the physical coupling of internal parts. What this means is that, when a key is depressed, the top end of the spring is pushed toward an electrode at the bottom until the capacitance reaches a certain threshold. At that threshold, the switch is actuated, and the rubber dome generates a "snap feeling" that gives the user some tactile feedback. The switch can then be pushed farther down until it bottoms out, or it can be allowed to spring back up to its resting position.
The patent application outlines an interesting rationale behind the design. It explains that conventional key switches need to be depressed "halfway down" to reach the actuation point. As a result, users may be inclined to bottom out in order to ensure that the switch is properly actuated. Over time, the patent application goes on to say, repeated impacts from bottoming-out can result in "inflammation of the tendon sheath." The patent calls such inflammation an "occupational disease" that provokes "social concern."
Topre's design purports to address this problem by putting the actuation point only 1-2 mm below the key's resting position—and by generating that aforementioned "snap feeling" to inform the user of a successful actuation. In theory, then, the user should have less of an incentive to bottom out, since he or she will need to push down only a small part of the way to actuate the switch and trigger the tactile bump. If Topre is to be believed, this should lead to less tendon sheath inflammation (and, I suppose, less social concern). More to the point, less bottoming out should mean less fatigue.
Topre filed its patent application way back in 1984, when IBM's buckling springs ruled the land. Big Blue's patent application indeed shows that buckling springs must be pushed down about half-way to be actuated. What of the Cherry MX switches that populate more modern mechanical keyboards? They aren't entirely dissimilar, as it turns out. This PDF on the Cherry website shows the pressure point ergonomic (brown) and linear (red and black) MX switches actuate at 2 mm out of a 4-mm travel distance. The pressure point click (a.k.a. blue) MX switch actuates at 2.25 mm out of 4 mm—even farther than the half-way point.
Neither the Topre patent nor the company's website quotes the exact actuation point for Topre switches. However, according to my measurements, the Type Heaven's keys actuate at roughly 1.5 mm, and they bottom out just after 4 mm. Actuation requires 45 g of force, which is the same as for Cherry's MX brown switches.
The Topres have another thing in common with the Cherry MX browns: both switch types provide tactile feedback without generating an audible click upon actuation. Discounting the different internal structures and different actuation points, these two switches—the Topres and Cherry browns—seem pretty comparable on paper. As we're about to see, though, they feel quite different.
Now, if you've ever used laptop-style keyboards with scissor switches or cheap desktop keyboards with rubber domes, you may be aware that those, like the Topres, require very little travel to actuate. However, because they also have a short travel distance, those switches bottom out very easily. That's precisely what Topre switches are designed to prevent. Rubber domes aggravate the problem with muddy response and a bouncy bottom-out point, which may encourage some users to push down even harder.
In short, Topre really may be on to something here, if the theory matches the reality. Let's find out if that's the case now.