Method and Apparatus for Brightness and Contrast Adjustment
Field of the Invention
The present invention is in the area of input devices for computer equipment, and pertains particularly to apparatus and method for adjusting brightness and contrast simultaneously for display terminals.
Background of the Invention
Display terminals for computers typically require adjustment of both brightness and contrast to attain an optimum viewing quality, which may vary from one user to another, and from one ambient light condition to another. Various methods have been used to provide adjustment for available display terminals. Among these are slide switches, knobs, keystroke combinations, and so on.
Adjustment is particularly important for displays used with portable computers, as portable units are typically used in a wide variety of ambient light conditions from full sun to very poor light.
It is known in the art that adjustment of one of contrast or brightness effects the visual perception of the other, and after one, is adjusted it is typically needed to adjust the other. In this fashion the attainment of an optimum setting for both is an iterative, time consuming, and sometimes frustrating process. What is needed is a means of contrast and brightness adjustment with a single input control having two degrees of freedom, movement in one degree adjusting one, and the other degree the other. An adjustment means of this sort would benefit also from a dedicated display screen designed to optimize visual efficiency.
Summary of the Invention
In a preferred embodiment a method for adjusting brightness and contrast is provided for a display monitor in a system with a pointing device. The method comprises steps of providing a first signal to the system to initiate an adjustment routine for monitoring pointer movement and converting components of the pointer movement to adjustment of brightness and contrast, manipulating the pointing device to adjust the relative levels of brightness and contrast, observing changes in brightness and contrast on the display screen, providing further movement of the pointing device as needed to make further adjustment of brightness and contrast, and providing a second signal to the system to terminate the adjustment routine when brightness and contrast are judged to be optimized.
Using a pointing device for adjusting the brightness and contrast allows the system to be built without slide switches, knobs, or other variable input devices to provide input for the adjustment, affording a saving in manufacturing cost and complexity, and therefore extending rel iabi 1 ity.
Also in a preferred embodiment a system is provided for adjusting brightness and contrast of a display monitor comprising a CPU, electronic memory means, a pointer device, a contrast and brightness adjustment control means for converting the pointer device input to adjustment of contrast and brightness level for the display monitor, initiating means for initiating the contrast and brightness adjustment control means, and termination means for terminating the contrast and brightness adjustment control means.
In yet another aspect of the invention a notebook computer is provided having a CPU, an electronic memory means, a display monitor, a keyboard, a pointer device, and contrast and brightness adjustment control means for converting the pointer device input to adjustment of contrast and brightness level for the display monitor. There is an initiating means and a terminating means for the contrast and brightness adjustment control means as well.
In a preferred embodiment the pointer device for the notebook computer is a trackball mounted in a handrest adjacent the keyboard. Also in a preferred embodiment the initiation means involves depression of a key combination on the keyboard, and the termination means involves releasing the same keys. In this and other embodiments, the pointer device input is resolved by treating movement in one direction as meant for brightness adjustment and movement in another direction as meant for contrast adjustment. The CPU receives digital info regarding pointer device movement, calculates proportional adjustment for contrast and brightness, and outputs digital values to digitally controlled analog devices for controlling brightness and contrast.
The apparatus and method of the invention saves components and complexity, as described above, and also is quick, easy, and intuitive for the user.
Brief Description of the Drawings
Fig. 1 is an isometric view of a notebook computer according to the present invention.
Fig. 2A depicts an exemplary display useful with a preferred embodiment of the invention.
Fig. 2B is a plan view of a trackball pointing device used with a preferred embodiment of the invention.
Fig. 3 is flow diagram depicting logic flow for a control routine used in a preferred embodiment of the invention.
Description of the Preferred Embodiments
Most modern desktop computers and workstations, and portable computers, such as laptop and notebook computers, incorporate pointing devices for cursor movement, menu selection, graphics element input, and the like. "Mouse" devices have been the most common pointing devices in the past, and trackball devices are rapidly becoming much more popular. Many system today have trackball pointing devices built into the input keyboard. Other pointing devices in use are joysticks, digitizers graphic tablets, light pens, and touch sensitive displays.
Fig. 1 shows a notebook computer 11 according to the present invention having a trackball device 13 built into a handrest 15 below and adjacent keyboard 17. The trackball may be reached conveniently by either hand, and "buttons" adjacent the trackball provide for input of incremental signals as known in the art. The trackball provides for cursor movement, graphics element input, and so forth, as described above and known in the art.
In the present invention, a pre-programmed signal to the computer system activates a control routine that monitors trackball movement, and uses the equivalent axial movement on one orthogonal axis to control contrast and the equivalent axial movement on the other axis to control brightness.
In a preferred embodiment the pre-programmed signal is simultaneous depression of the combination of the three keys at the lower left of the keyboard, which, in most standard keyboards is Ctrl-Shift-Alt. These keys are indicated by element number 19 in Fig. 1. In other embodiments, other keys combinations might be used, and other initiating signals could be used as well.
In a preferred embodiment, the three initiating keys are held down by one hand while the trackball is manipulated with the other, and the control routine of the invention is terminated when the user releases the three keys. This embodiment, with the keys on the lower left corner of the keyboard, is convenient for right-handed users. An equivalent embodiment uses keys at the right of the keyboard, and pointer manipulation is accomplished with the left hand.
Holding the initiating key combination depressed while using the pointer to set brightness and contrast is also a convenience. In other embodiments a key signal can work as a toggle, and the second momentary depression of the initiating key combination can terminate the control routine. It will be apparent to one with skill in the art that there are many ways to signal initiation and termination of the control routines.
In state-of-the-art systems, brightness and contrast control is typically accomplished by manual setting of switches or knobs configured as voltage-divider circuitry, so the manual setting controls an output voltage that may directly or indirectly control brightness and contrast. In the system of the present invention, there are no manual slide switches or knobs for the purpose, and the CPU outputs digital signals proportional to movement of the pointer device, which in the preferred embodiment is a trackball device. Adjustment of brightness and contrast levels are then made by digitally controllable analog devices that respond to the digital signals proportional to trackball movement by providing an analog output proportional to the digital input.
Fig. 2A shows an exemplary screen displayed as a result of the signal to initiate the control routine that accepts signals from the pointer device, in this case trackball 13, and uses the input to adjust brightness and contrast. Fig. 2B is a top view of trackball 13.
It is not required by the invention that any particular graphic display be made available for setting brightness and contrast. The system of the invention works well without a dedicated display, and can be initiated while leaving whatever display is current at the time of initiation. A dedicated display, however, provides, in some cases, a better visual vehicle for ascertaining differences in brightness and contrast. In the exemplary display shown in Fig. 2A, a rendition of the Manhattan skyline is provided as a vehicle for setting the brightness and contrast, and a cursor 31 is shown at the position on the screen where movement of the pointer device dictates. Like the dedicated display, operation of the invention does not require cursor display, but having the cursor displayed and moving as the adjustments are made, provides an additional advantage. The user can remember the cursor position for a setting that is particularly useful under specific conditions. A disadvantage of a dedicated display is the need to have that display stored somewhere in computer memory.
Whether or not a dedicated display is used, whether or not a cursor is displayed, and regardless of the means of initiating and terminating the control routine, the adjustment of brightness and contrast operates the same. In the embodiment shown, equivalent movement of the pointer device that would move a screen cursor vertically adjusts brightness, which is indicated as less bright from the bottom of the screen to brighter toward the top of the screen. Movement of the pointer device that would move the screen cursor horizontally adjusts contrast, which is indicated from minimum contrast at the left edge of the screen to maximum contrast at the right edge of the screen.
As an example, vector 25 indicated on the screen of Fig. 2A represents a cursor movement that might be made by moving the pointer device. Vectors 27 and 29 are the orthogonal component vectors of vector 25. With the control routine of the invention active, movement of the pointer device indicated by vector 25 is resolved into vectors 27 and 29, and adjustment is made in contrast and brightness accordingly. Vectors 25, 27, and 29 are exemplary, and are not typically illustrated on the display screen.
The plan view of trackball 13 in Fig. 2B indicates the relation ship between trackball movement and the resolved adjustment vectors for brightness and contrast adjustment. Movement of the trackball in the direction of arrow 23 provides contrast adjustment in the embodiment described, and movement of the trackball in the direction of arrow 21 provides brightness adjustment.
There are several equivalent ways the control routines might be loaded and implemented for use by a computer system, such as the notebook computer shown in Fig. 1. One is by the Basic Input Output System (BIOS) which may have the routine built in, or which may be enhanced (in the case of reprogrammable BIOS) to contain the control routine. An alternative embodiment uses a DOS based utility. Other ways known in the art may also be used.
Fig. 3 is a block diagram illustrating the logic flow of the control routine of the invention. Initiate signal 33 causes the control routine to start at block 35. The initiate signal can take one of several forms, as described above, and the control routine can be archived in one of several different ways, such as in the BIOS, as also described above.
After initiation the system monitors pointer movement (block 37) and converts pointer movement to adjustment of brightness and contrast levels. The full range of brightness and contrast available is a function of the system hardware configuration, which a known quantity, and the control routine converts cursor movement to degree of adjustment proportionally according to the degree of cursor movement related to the vertical and horizontal limits; that is, the width and height of the active display.
At block 39 a horizontal cursor movement "x" which may be + or -, is converted to a relative degree of contrast adjustment. The direction of + and - is arbitrary, but it is convenient to relate + to increase in contrast or brightness, and - to decrease. Accordingly, at block 41 contrast is increased, and at block 43, contrast is decreased proportional to the degree of cursor movement sensed.
At block 49 vertical (y direction) movement of the pointer is converted to brightness adjustment. Positive (+) movement is applied to increase in brightness and negative (-) movement is applied to decrease in brightness. At block 51 the routine senses for a terminate signal, and if that signal is present, terminates (block 53). If the terminate signal is not present, control loops back to block 37, and further movement of the pointer device is monitored.
Movement through the routine is related to the system clock rate and rapid enough, so each adjustment is small enough, that cursor movement on the display screen and change in brightness and contrast level seems quite smooth and analog, just as cursor movement is displayed in existing application programs. As brightness and contrast are altered in the manner described the visual appearance of the image on the screen changes accordingly, and the user has the feedback needed to make further adjustment through further pointer device movement. In the case of the embodiment described above, the image on the screen is the Manhattan skyline, and the relative detail of the graphic image is a convenience in making judgement in adjustment.
It will be apparent to one with skill in the art that there are many alterations that may be made without departing from the spirit and scope of the invention. Many such changes in detail have been enumerated above, such as the presence or absence of a dedicated image for visual feedback, and the use of several different kinds of pointer devices. There are many other such changes. For example, the system of the invention may be applied to any sort of monitor used with many different computer systems, and even with monitors used with dedicated instruments other than general-purpose computers. There are many more such alterations in detail that might be made without departing from the spirit and scope of the invention.