Here’s a paper showing rubber domes vs. scissor switches:
http://faculty.washington.edu/petej/Hughes,TypingBiomechanics,HFES2011.pdfTo be honest, not a very useful paper. Here’s from the conclusion: “It was difficult to distinguish between the effects of switch mechanism and travel distance since there was no available long travel scissor switch keyboard or short travel dome keyboard available for use in the study.”
They found that the Apple scissor switch was preferred to a generic crappy rubber dome though. (Not surprising: I agree with that too.)
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I don’t have access to read this paper:
http://journals.lww.com/joem/Abstract/1999/02000/Effect_of_Keyboard_Keyswitch_Design_on_Hand_Pain.6.aspxI can’t tell which switches they tried, but their abstract says “Keyboard assignment had no significant effect on change in hand function or median nerve latency. We conclude that use of keyboard A for 12 weeks led to a reduction in hand pain and an improved physical examination finding when compared with keyboard B. There was no corresponding improvement in hand function or median nerve latency.”
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This paper ...
http://www.researchgate.net/publication/13315321_Computer_key_switch_force-displacement_characteristics_and_short-term_effects_on_localized_fatigue/file/9c96052542b4f5a037.pdf... talks about how when the actuation point is near the bottom of key travel, it leads to increased force at the bottom of the keypress, and describes how decreasing the distance to actuation increased typing speed. The main point of the paper seems to be that reducing the overall force required reduced the force exerted by users, and probably leads to less fatigue. Overall, I’m not super satisfied by either their experiments or the way they analyze them. Their switches were not anything in common use, but rather some hacked-together custom things, which allowed them to vary parameters.
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This paper compared buckling springs to rubber domes:
http://www.researchgate.net/publication/8475230_Effects_of_keyswitch_design_and_finger_posture_on_finger_joint_kinematics_and_dynamics_during_tapping_on_computer_keyswitches/file/d912f51394dd1c3992.pdfFrom my quick skimming of their charts, the buckling springs come out ahead, but it’s not super easy to judge.
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http://ergo.berkeley.edu/docs/1999gerardamindhygassocj.pdf“Buckling spring keyboards have different feedback characteristics from dome keyboards such that subjects type on a 0.72 N spring keyboard with approximately the same typing force, finger flexor and extensor EMG, and subjective discomfort as they do on a 0.28 N dome keyboard.”
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This paper compared buckling springs to rubber domes and also includes a low-travel rubber dome:
http://www.researchgate.net/publication/51394183_Computer_keyswitch_force-displacement_characteristics_affect_muscle_activity_patterns_during_index_finger_tapping/file/d912f51394dd13e4b2.pdf* * *
Here’s a literature review.
http://iospress.metapress.com/content/l856552136tl1g71/It’s paywalled, so I can’t see their full paper, but from the abstract:
“Results: General conclusions that can be drawn from these studies are: greater make forces result in increased keyboard reaction forces and EMG activity, users strike keys with forces 2–7 times the required make force and that they employ a ballistic finger motion to do so. Furthermore, typists tend to prefer kinesthetic and auditory feedback.
“Conclusions: Due to the ballistic nature of typing, new keyswitch designs should be aimed at reducing impact forces. Future studies should examine the role of breakaway force and over travel as limited research has been done on the role of these parameters.”
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Here’s a comparison of mechanical vs. rubber dome switches from the early 1980s:
http://www3.alcatel-lucent.com/bstj/vol62-1983/articles/bstj62-6-1733.pdf* * *
This looks pretty interesting, but I can’t access it:
http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=531936&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Farnumber%3D531936* * *
This paper seems to recommend low travel distance to actuation, but lots of post-actuation travel. I don’t have access to the full thing:
http://hfs.sagepub.com/content/39/1/130.abstract* * *
In this paper, the abstract (full text is paywalled) seems to suggest that people preferred a buckling spring keyboard to a rubber dome, but when they had to choose between rubber domes, they preferred one that required a medium amount of force:
http://www.tandfonline.com/doi/abs/10.1080/00028899908984499#.UyPBXNzob-k* * *
These papers looks interesting. Anyone able to read them?
http://pro.sagepub.com/content/36/5/523.abstract“Two keyboards had linear spring key action, one with low (key force) resistance (42.5 grams) and one with high resistance (70.9 grams). The other two keyboards had tactile (snap) action, one with low resistance (35.5 grams) and one with high resistance (70.9 grams). All four keyboards were manufactured by the same company, and were visually identical in size, layout, color, etc. There was no difference in typing sound and traveling distance among the four keyboards.”
http://pro.sagepub.com/content/28/3/267“Both groups of typists indicated about equal preference for keyboards with snap-spring and elastomer key actions and much lower preference ratings for the keyboard with a low-resistance, linear spring key action mechanism. Fewer errors and faster typing throughput were obtained on keyboards with the elastomer key action than on the other two keyboards, equipped with snap- and linear-spring key action mechanisms.”
(Judging from a summary in another paper, what they mean by “elastomer” action is basically a tactile keyswitch with actuation/tactile point a noticeable distance before bottom-out.)
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This is supposed to be a good research review:
http://www.sciencedirect.com/science/article/pii/S0169814102001804But again, I don’t have access.
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I’ve definitely skimmed several other papers in the past that I couldn’t find in a quick google scholar search. But as I said in a previous post, those papers, and the ones linked here, are all pretty unsatisfactory.