1. Field of the Invention
This invention pertains to multi-positional controls and more specifically to such a control that provides multiple electrical control outputs dependent on the multi-positional manipulations of such control, which control is commonly referred to as a "joystick".
2. Description of the Prior Art
Joystick controllers have long been employed in aviation as a convenient means of providing the pilot with an easy manipulative control over one or more controlled devices. That is, by positioning the joystick front to back, the attitude of the plane is lowered or raised, the external devices achieving such action being controlled by the joystick. In similar fashion, positioning the joystick to the left or to the right causes corresponding banking and ultimate turning of the aircraft through the controlled wing and tail parts that achieve such action. The pilot can accomplish both these controlled actions simultaneously by moving a single stick, while still being able to use the other free hand for operating other controls.
Joysticks are useful in other applications besides aircraft control. For example, a handicapped person might be able to operate a small handle to control a wheelchair or even a more complex machine but not be able to operate a wheel or even multiple switches or buttons. These actions either require more strength, complex physical dexterity or a different dexterity than is required in a simple single stick control operation.
The boom in video and other modern games has presented a need for more rugged, yet not overly complex controllers. For example, a player often must achieve complex manipulation of parts and/or the manipulation of multiple parts during the course of play and must make these manipulations over and over again. The newer three-dimensional games place an even further movement requirement on the pieces and requires further demands to the control apparatus for moving these pieces not only with respect to the axes of a planar surface or board, but with respect to the depth or perspective dimension. Consider, for example, the controls required to manipulate a video game "spaceship" through a three-dimensional field of "asteroids".
The examples of use are numerous. The above applications are merely by way of example and not limitation.
Joysticks in the past have achieved their functions by converting the angular motion of a control rod to circular motion about two perpendicular axes, thereby rotating a potentiometer or variable resistor in each of the two axes. Thus, the operator is provided with two separate control outputs. Although operationally satisfactory in most cases, the type of construction just described has a short lifetime because the carbon tracks in the potentiometer wear out with repeated usage. Deterioration may cause output discontinuities as well as gradual value changes which could result in inaccurate and perhaps even harmful results. Furthermore, since sufficient force must be exerted on the control rod to overcome the wiper friction in the potentiometer, the control manipulation may be difficult for the weak or handicapped. Also, such drag causes the precision and/or sensitivity of control not to be as great as one would want in many cases. Moreover, to achieve more than two independent varying output signals by manipulating a single stick has not been readily possible using multiple-axes potentiometers.
Prior art patents in joysticks using optical devices include the structures described in U.S. Pat. Nos. 3,521,072 (Wipson, et al.); 3,811,047 (Shagral); and 3,886,381 (Wester). Wipson, et al. discloses a pivotal control shaft with a mask element disposed between a light emitter and dual photoconductors as detectors. The mask shades both photoconductors when the shaft is in a central neutral position, but uncovers one or the other of these photoconductors when the shaft is tilted to produce a positive or a negative signal, thereby achieving a servocontrol type output. A second mask element with a second set of photoconductors are used for servocontrol purposes in an orthogonal direction.
Shagral uses four spaced apart light receivers illuminated by a pivoted shaft-mounted light. As the light is pivoted, the pattern on the light receivers is varied, providing comparative information.
Wester utilizes eccentric arcuate surfaces mounted vis-a-vis a control shaft. Variation in distance of the surface from detectors differentially connected together reveals information. The two orthogonal axes are not independent. Furthermore, it should be noted that the fulcrum is preferably a rubberized diaphragm for automatic approximate resetting of the shaft.
Many patents show structures unrelated to joysticks that utilize optical detection for servocontrol purposes. For example, U.S. Pat. Nos. 3,071,976 (Kunz) and 3,270,567 (Crampton) shows structures which optically detect a rotating or spinning spherical gyroscope surface using a light emitter/detector combination. U.S. Pat. No. 3,770,965 (Edwards, et al.) reveals the utilization of a graduated slot connected to a galvanometer photosensor feedback loop. A photosensor feedback signal detecting the slot size and servocontrols the galvanometer back to a neutral position. U.S. Pat. No. 4,103,155 (Clark) discloses the production of an indication of the degree of cylinder rotation using sensors detecting a graduated darkened pattern on the surface of the cylinder.
The following U.S. patents pertain generally to photoresistor elements: U.S. Pat. Nos. 3,258,601 (Suleski); 3,358,150 (Summer): 3,639,769 (Clark): and 3,859,617 (Oka, et al.). None of these patents pertain to a joystick application and the structures are all dissimilar to anything disclosed in the preferred embodiments of the present invention.
Therefore, it is a feature of the present invention to provide an improved joystick using optical principles in such a manner to provide multiple outputs through the manipulation of a single rod.
It is another feature of the present invention to provide an improved optical joystick including a sphere with a changing-property surface, such as by paint or otherwise, the surface being optically detectable with position changes in the joystick to produce electrical outputs corresponding to the optically detected surface changes.
It is still another feature of the present invention to provide an improved optical joystick which produces three outputs, one in response to a forward and backward movement of the joystick, one in response to a sideways movement, and one with a rotation manipulation of the joystick.
It is yet another feature of the present invention to provide an improved optical joystick which has three outputs dependent on the manipulation thereof and includes, in addition, a concentrically mounted thumb control for providing additional outputs dependent on thumb manipulations thereof, these additional outputs obtainable via another and miniature sphere also with a gradual changing surface.