Optical Scroll Mouse is a small device that a computer user pushes across a desk surface in order to point to a place on a display screen and to select one or more actions to take from that position. The mouse first became a widely-used computer tool when Apple Computer made it a standard part of the Apple Macintosh. Today, the mouse is an integral part of the graphical user interface of any personal computer. The mouse apparently got its name by being about the same size and color as a toy mouse. A mouse consists of a metal or plastic housing or casing, a ball that sticks out of the bottom of the casing and is rolled on a flat surface, one or more buttons on the top of the casing, and a cable that connects the mouse to the computer. As the ball is moved over the surface in any direction, a sensor sends impulses to the computer that causes a mouse-responsive program to reposition a visible indicator (called a cursor) on the display screen. The positioning is relative to some variable starting place. Viewing the cursor’s present position, the user readjusts the position by moving the mouse.
The most conventional kind of mouse has two buttons on top: the left one is used most frequently. In the Windows operating systems, it lets the user click once to send a “Select” indication that provides the user with feedback that a particular position has been selected for further action. The next click on a selected position or two quick clicks on it causes a particular action to take place on the selected object. For example, in Windows operating systems, it causes a program associated with that object to be started. The second button, on the right, usually provides some less-frequently needed capability. For example, when viewing a Web page, you can click on an image to get a popup menu that, among other things, lets you save the image on your hard disk.
Although the wireless optical mouse has become a familiar part of the personal computer, its design continues to evolve and there continue to be other approaches to pointing or positioning on a display. Notebook computers include built-in mouse devices that let you control the cursor by rolling your finger over a built-in trackball. IBM’s Scroll Point mouse adds a small “stick” between two mouse buttons that lets you scroll a Web page or other content up or down and right or left. Users of graphic design and CAD applications can use a stylus and a specially-sensitive pad to draw as well as move the cursor. Other display screen-positioning ideas include a video camera that tracks the user’s eye movement and places the cursor accordingly. Optical scroll mice have a number of benefits over older technologies. One of the biggest benefits is that the elimination of the mouse ball, which frequently required cleaning to scrape accumulated grime of the ball or the rollers inside. As there are no moving parts in optical mice, almost no maintenance or regular cleaning is required. Another benefit is that digital processing often results in smoother, more accurate performance than prior technologies. Optical mice typically don’t require a mouse pad and can be used on many surfaces, including those that are not entirely flat.