Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!elroy.jpl.nasa.gov!sdd.hp.com!uakari.primate.wisc.edu!aplcen!boingo.med.jhu.edu!haven.umd.edu!mimsy!tove.cs.umd.edu!sears From: sears@tove.cs.umd.edu (Andrew Sears) Newsgroups: comp.human-factors Subject: Re: Touchscreens Message-ID: <35578@mimsy.umd.edu> Date: 13 Jun 91 15:57:53 GMT References: <8435@awdprime.UUCP> <6460@ns-mx.uiowa.edu> Sender: news@mimsy.umd.edu Reply-To: sears@tove.cs.umd.edu (Andrew Sears) Organization: U of Maryland, Dept. of Computer Science, Coll. Pk., MD 20742 Lines: 96 In article <6460@ns-mx.uiowa.edu> jones@pyrite.cs.uiowa.edu (Douglas W. Jones,201H MLH,3193350740,3193382879) writes: >From article <8435@awdprime.UUCP>, by jon@kitty.austin.ibm.com (Werner): > >> Are there any papers written dealing with the use of touchscreens as an >> alternate input device in environments which don not have enough desk >> space for a keyboard or a mouse? > >I don't know of any papers, but as a long-term touch-panel user, I much >prefer mice, trackballs, or knobs on my keyboard. > >I used the U of Illinois Plato touch panels between 1973 and 1980, and There is a growing number of articles published on touchscreens, many of which have been written by members of the lab I work in, HCIL at the University of Maryland. First, I'd like to point out that touchscreens have improved dramatically in recent years. In addition, many of the problems that you mention have been investigated. >the big problems are: > > 1) You have to lift your hand up from the keyboard, perhaps a foot, > to touch the screen. This slows you down compared to horizontal > moves to a mouse. This is not necessarily true. There have been some studies that compared the touchscreen and mouse for tasks that involve typing. Typically, the touchscreen proves faster than the mouse. This is believed to be due to the fact that the user does not have to divert their attention from the screen to find the mouse. > > 2) No matter how good the anti-reflection coating on your screen is, > fingerprints tend to defeat it. If you've got a touch panel, you'll > need to wash it almost daily to keep the glare down. Glare can be a problem with touchscreens. However, touchscreen manufacturers are always decreasing glare. This combined with careful lighting can dramatically reduce this problem. The touchscreens in our lab tend to need very infrequent cleaning. Actually, the thin film of oil from your finger tends to prevent dust from accumulating. > > 3) If you have touch-intensive software, where you spend long periods > holding your hand up to the screen poking here and there, your arm > gets tired. I remember after some sessions debugging a particular > touch-intensive piece of computer aided instructional material, my > arm began to ache quite intensely. I've never experienced that kind > of reaction to "desktop pointers" like mice. This has always been a common complaint. However, simply changing the angle the monitor is mounted at can dramatically reduce this problem. We have conducted a study comparing several alternatives, 30, 45, and 75 degrees from horizontal. The 75 degree angle (near normal monitor position) was a clear looser. Additional studies by researchers in Sweden appear to support our results that indicate placement at approximately 30 degrees from horizontal is more comfortable and preferred. An article in the Journal of the American Optometric Association also suggests that lower screen placements will reduce eye strain. > > 4) Touch panels aren't particularly accurate. Even if you use a modern > thin-film touch panel, there is a real problem with paralax. The > front of a CRT display is quite thick, and the push button size we > typically use with mice is small enough that it can be very hard to > find the right spot on the screen to touch to get a particular > button and not its surrounding area. The Iowa City Public Library > on-line card catalog has been touch screen based for a few years > now, and I've had numerous paralax problems with it, even thoug it > has nice big on-screen push buttons. Touchscreens can be very accurate if used correctly. New touchscreen technologies offer resolusion of over 1000x1000 on an IBM PC screen. If appropriate feedback is provided and the correct selection strategy used, users with moderate experience can select even a single pixel from a 13 inch EGA monitor (under 1mm square). Studies have shown that novice users can select targets as small as 2mm per side as fast as they can with a mouse without any loss of accuracy. > > Doug Jones > jones@cs.uiowa.edu Well, this is long enough already. If anyone is interested in references for what I've stated here, or just additional references on touchscreen research (my own or others) please feel free to send me email (sears@cs.umd.edu). I will be more than happy to aim you at some of the more recent literature on touchscreens. Andrew Sears ----------------------------------------------------------------------------- Andrew Sears sears@CS.umd.edu Human-Computer Interaction Laboratory University of Maryland, College Park, MD 20742 (301) 405-2725