Keyboard keys or mouse buttons with active rebound

BACKGROUND

The present invention relates to input devices, such as a keyboard, a mouse, or other devices having keys or buttons. More specifically, this relates to an active rebound system for such input devices.

Keyboards, an essential part of most computer systems, are responsible for the substantial majority of computer-related injuries. Many computer keyboards are based on typewriter models. They often do not take human needs and physiology into account.

Repetitive Stress Syndrome conditions, such as Carpal Tunnel Syndrome, are common repetitive motion injuries attributed to the use of computer peripheral devices that require repetitive finger motions. To relieve muscle strains that cause these injuries, arms should point straight down and then bend into right angles at the elbows. However, most typists force their arms and wrists into uncomfortable and unnatural positions. These positions cause inflammation of delicate muscles and consequently apply pressure against the nerves that pass through a narrow sheath called the carpal tunnel.

SUMMARY

An active rebound circuit has a device that assists users to lift their fingers upward to relieve some repetitive motion stress. The device is adapted to respond with a rebound force when a first force is applied to the device. The rebound force should be effective to provide reduction in work expended in applying a second force in an opposite direction to the first force.

BRIEF DESCRIPTION OF THE DRAWINGS

Different aspects of the present invention will be described in reference to the accompanying drawings wherein:

FIG. 1

illustrates the user exerting a relatively large amount of force pressing the keyboard keys downward;

FIG. 2

illustrates the active rebound key system providing an upward force to the user's finger;

FIG. 3

shows an active rebound circuit according an embodiment of the present invention;

FIG. 4

shows a rebound force setting according an embodiment of the present invention;

FIG. 5

is a block diagram of an active rebound system according an embodiment of the present invention;

FIG. 6

is a flowchart of the rebound force determination and application process; and

FIG. 7

is a block diagram of a computer system having an active rebound system.

DETAILED DESCRIPTION

Some of the computer-related repetitive motion injuries can be minimized by the use of keyboard keys or mouse buttons that preclude the need for antagonistic muscle use. These muscles involve repetitive opposite direction motions that require the muscles to contract simultaneously. For example, the human hand is adapted for grasping. Thus, the fingers are built for clutching objects. The fingers, therefore, often exert substantially more force inward than outward.

FIGS. 1 and 2

illustrate the use of a computer keyboard involving movement of fingers. The fingers, in

FIG. 1

, exert a relatively large amount of force pressing the keys downward. This large force is due to natural adaptation of human fingers to exert more force inward. However, the rebound of the keys is currently dependent on a passive spring or foam type material. This passive rebound material returns a small fraction of the energy to the hand and finger that was expended to press the key downward. Therefore, a substantial portion of the work expended in the use of keyboard involves lifting the fingers and hand, especially at high key press repetition rates. This often leads to poor keyboard use habits through repetitive wrist flexing, which may lead to possible repetitive stress injuries.

The present disclosure describes an active rebound key. This circuit assists users in lifting their fingers upward. An active circuit in the rebound key can substantially reduce the work involved in moving the mass of a finger up and down repetitively. This repetitive motion may generate more than 40 repetition cycles per minute per finger.

One embodiment of the active rebound circuit

300

is shown in FIG.

3

. When the user's finger

316

presses down on a key

306

, a downward force

310

causes an attached plunger

312

to slide along a rod, such as an iron armature

314

. The armature

314

has a proximal end

320

and a distal end

318

. The distal end

318

is attached to a conductive support

322

. When the force

310

applied to the key

306

is sufficient, the proximal end

320

of the armature

314

makes contact with a conductive patch

324

on a key switch assembly

308

. Therefore, the key switch assembly

308

and the armature

314

act as a contact switch.

When the armature

314

makes contact with the patch

324

, a signal

326

is sent that identifies the pressed key

306

. The signal

326

that indicates the pressed key also triggers a solenoid of field coil

302

built into the circuit

300

. The solenoid

302

directs an active short duration upward force

304

to the key

306

., which provides an active rebound. The upward assist provided by a keyboard equipped with such keys would alleviate much of the antagonistic muscle use. The average user can press the same key with the same finger approximately every 150 milliseconds for a short duration. Therefore, the alleviation is especially important when the same key is being pressed repetitively, such as the left mouse button or the space bar on the keyboard.

In some embodiments, the rebound force and speed can be altered to suit the specific fingers of the human hand. The two fingers with the most different mass and strength are the thumb and 5th finger. The 5th finger is used to press the Return key (often referred to as the Enter or Carriage Return key) in a standard QWERTY keyboard. The thumb is used to press the space bar, which is one of the most frequently and repetitively pressed keys. A keyboard with user settable rebound allows users to set the rebound force to the most comfortable level for each finger of the hand.

In other embodiments, preferred rebound force settings for a specific user are saved in a file. A computer uses this file to control the rebound system of the keyboard or other devices. Keyboards that have a stand-alone active rebound system use a separate small micro-controller and memory system to store individual force setting maps, such as shown in FIG.

4

.

In another embodiment, the rebound settings are dynamically altered depending on typing patterns. For example, repetitive pressing of a key by the same finger is often the most tiring and stressful. Therefore, when the user is deliberately pressing the same key repetitively (but not holding the key down so that it electronically auto-repeats), a controller can dynamically increase the rebound level. The level increase depends on the rate of repeated pressing.

In further embodiments, the rebound settings are altered depending on how long the user holds a key down. For example, modifier keys, such as the Shift or Control keys, are held down longer than character keys. Thus, the programmed rebound settings are reduced for these keys. In another embodiment, the rebound settings are reduced when the text is being typed deliberately slowly to avoid errors or when typing long and difficult words.

FIG. 5

is a block diagram of an active rebound system

500

according an embodiment of the invention. The embodiment

500

includes a key rebound map

502

, a processor

504

, an actuator

506

, and an active rebound circuit

300

. The key rebound map

502

includes a table of rebound force settings. The settings can be determined using one of the methods described above. The rebound processor

504

selects an appropriate rebound force setting for a particular key press

510

on a keyboard. The processor

504

selects the setting from a table

512

received from the rebound map

502

. The selected force setting

514

is sent to the rebound actuator

506

.

The rebound actuator

506

converts the rebound force setting received from the rebound processor

504

into an electrical signal sufficient to provide active rebound to the pressed key. The electrical signal

516

representing the rebound force is applied to the solenoid

302

in the active rebound circuit

300

.

FIG. 6

is a flowchart of the rebound force determination and application process according to an embodiment of the present invention. The processor determines which key is pressed, at step

600

. The processor also determines the duration of the key pressed, at step

602

. At step

604

, the processor computes the rebound force setting for the pressed key using the rebound map. The processor then sends the determined force setting to the rebound actuator, at step

606

. The rebound actuator applies the equivalent electrical value to the solenoid in the active rebound circuit.

FIG. 7

shows a block diagram of a computer system

700

including an active rebound system

500

having a rebound circuit

300

according an embodiment of the present invention. The computer system

700

also includes a processor

702

, a display

704

, a memory

706

, and input/output (I/O) devices

708

. The active rebound system

500

provides rebound force to assist users in lifting their fingers upward. A rebound circuit in the key substantially reduces the work involved in moving the mass of a finger up and down repetitively.

Other embodiments are within the scope of the following claims. For example, the control functions to allow users to alter the parameters of the rebound to their preferences can be applied using Universal Serial Bus (USB) connection. Further, the active rebound circuit can be used in applications other than computer keyboards, such as in computer mice, electronic music keyboards, and piano keyboards. Also, the key switches used may be of the electrical contact variety or of the contact-free variety, such as Hall-Effect switches or capacitive switches.