Multidirectional switch actuator and a personal digital assistant using the same

[0001] This invention relates to an actuator for actuation of a switch from at least two orthogonal directions. This invention also relates to a personal digital assistant that uses the actuator for actuating a notification switch.

[0002] Devices such as personal digital assistants (PDA) or palm-sized personal computers (P/PC) are fast becoming popular for keeping track of appointments and a list of to-do tasks (“to-dos”) in our modern world. The applications on these devices support capturing of these appointments and tasks. These applications also provide a reminder feature for alerting a user of an upcoming appointment, event or task. The reminder feature usually causes a visual as well as an audio alert to be generated on the device. A light indicator that is strategically located on the device provides the visual alert. The visual and audio alerts can be generated periodically until a user has acknowledged the reminder. The user acknowledges the reminder by pressing a button on the device or by tapping on a touch-screen display. Such a method of acknowledging a reminder is sometimes cumbersome to a user, especially so when the device is stored away. It is therefore desirable to provide the user with a notification switch that is accessible from the outside of the device which the user can simply activate to acknowledge a reminder.

[0003] As these devices are usually small and easily stored in a shirt pocket, this notification switch should preferably be located on an accessible side of the device when the device is stored in the shirt pocket. This side of the device is usually a back wall of the device due to other design constraints. However, if located on such a back wall of the device, this notification switch will be hidden from view and difficult to access when the device is in use. A second notification switch can be introduced on the device but space being a major constraint on such a device does not always permit such an option.

[0004] From the foregoing, the prior art therefore has a need for an actuator of a notification switch that can be actuated from two orthogonal directions. This switch should preferably fit into a personal digital assistant without taking up too much valuable space.

[0005] In accordance with a preferred embodiment, an actuator suitable for multi-directional actuation of a push button switch has an actuation button and a plunger. The actuation button has a surface for multi-directional activation. The plunger is attached to the actuation button to define a predetermined angle therebetween. The actuator also has a hinge means that is attached to either the actuation button or the plunger for pivotably mounting the actuator about a pivoting axis. Activation on any point on the surface of the actuation button results in a unidirectional moment about the pivoting axis to tilt the plunger to releasably actuate the push button switch.

[0006] In another aspect of the invention, the actuator described above is used in a device such as a personal digital assistant for actuating a notification switch. Preferably this actuator also serves to provide a visual alert.

[0014] Hereafter, a preferred embodiment will be described in the context of a palm-sized personal computer (P/PC) that has an actuator according to the present invention for multidirectionally actuating a notification switch. However, it is to be understood that the invention is equally applicable to other types of devices such as electronic organizers, handheld personal computers, notebook computers, laptop computers and the like.

[0015] FIG. 1A is an isometric view of a palm-sized personal computer 2 (P/PC) that has an actuator 4 for multi-directionally actuating a switch 6 (FIG. 2). FIG. 2 is a sectional isometric view of a portion of the P/PC showing the actuator 4 assembled on the P/PC 2 for accessibility from two substantially orthogonal surfaces. This P/PC 2 has a housing 7 that contains a printed circuit board assembly 8 (PCBA) and a touch-screen display module 10. The PCBA has electronics and appropriate software that allow it to function as a controller board for controlling the operations of the P/PC 2. The software includes an operating system (OS) such as the Windows CE OS and personal information management applications such as Tasks and Calendar available from Microsoft. The Tasks application allows a user to maintain a list of to-dos. The Tasks application captures information such as task descriptions, due dates and other information. The Calendar application allows a user to maintain a list of appointments, each of which logs information such as appointment description, date, time and venue. These applications provide the user with an option of setting a reminder for each task or appointment entered. The reminder can be in the form of an audio alert, a visual alert or both. In this preferred embodiment, a light emitting diode (LED) on the controller board emits light to provide the visual alert. The actuator 4 is preferably of a diffused translucent plastic such as polycarbonate. Such an actuator 4 functions as a light guide to illuminate the actuator 4 so that emitted light is viewable from outside of the housing 7. The reminder can be a one-time reminder or it can be periodically generated until acknowledged by a user. The user acknowledges a reminder by sending an appropriate signal to the controller board 8. This signal can be sent by actuating any switch on the P/PC, including the notification switch 6, or by touching the touch-screen display module 10.

[0016] When the P/PC 2 is placed in a shirt pocket or a side pocket of a bag, the actuator 4 remains accessible for a user to receive a visual alert and to respond to it. FIG. 1B shows a side view of the P/PC showing that the actuator 4 is accessible in this view. FIG. 1C is another view of the P/PC 2 orthogonal to the view in FIG. 1B wherein the actuator remains accessible. This view is what a user sees when using the P/PC 2. Although when using the P/PC 2, the user can respond to a reminder In many other ways, it is intuitive for the user to want to depress the actuator 4 for turning off an alert. This intuition is especially so when the user is accustomed to turning off the alert by actuating the actuator 4 when only the view of the P/PC 2 in FIG. 1B is seen.

[0017] The housing 7 of the P/PC 2 has a frame 12. The PCBA 8 is mounted to a bottom of this frame 12. On one end of the PCBA 8 is mounted the notification switch 6. The actuator 4 is pivotably mounted about a pivoting axis on a back wall 14 of the frame 12. The actuator 4 sits on the notification switch 6 and can be tilted to actuate the notification switch 6. This notification switch 6 is preferably a low profile dome switch. The display module 10 is mounted on the PCBA 8 to sandwich a plunger 16 of the actuator 4 therebetween. Such an assembly is space economical since the thickness of the plunger 16 need not be any more than the height of the electronic components on the PCBA 8.

[0018] FIG. 3A is an isometric view of the actuator 4. FIG. 3B is a side view of the actuator 4 and the dome switch 6 as seen in the direction of an arrow B in FIG. 3A. The actuator 4 has an actuation button 18 that is attached to the plunger 16. In the preferred embodiment, the angle between the actuation button 18 and the plunger 16 is substantially orthogonal. Attached to an outer corner 19 of an intersection of the actuation button 18 and the plunger 16 is a pair of laterally extending hinge pins 20 that have a common pivoting axis. The actuation button 18 has an actuation surface 22 that has a curved surface 23 at a distal end from the hinge pins 20. A force applied to any portion of this surface 22 will result in a unidirectional moment, indicated by an arrow A in FIG. 3B, about the pivoting axis to tilt the plunger 16 against the dome switch 6 to actuate it. As a result, this actuator 4 allows actuation of the dome switch 6 from any direction between two substantially orthogonal directions indicated by arrows C and D in FIG. 3B. The direction of activation indicated by arrow C is substantially parallel to a plane 25 (FIG. 3A) of the plunger 16.

[0019] The assembly of the actuator 4 on the frame 12 of the P/PC 2 is next described with the aid of FIG. 2. On the back wall 14 of the frame 12 is a groove 24. This groove 24 has a U-shape cross-section. An opening 26 on one side of the groove 24 allows the plunger 16 to protrude into the confines of the frame 12. Another opening on an opposing side of the groove 24 exposes the surface 22 of the actuation button 18. The actuator 4 is inserted into this groove 24 to allow the hinge pins 20 to rest on the bottom of the groove 24 and to rock therein.

[0020] The actuator 4 preferably has at least one guide pin 28 that is attached to a side of the actuation button 18. This guide pin 28 prevents the actuator 4 from tilting over the pivoting axis during assembly of the P/PC 2 by restricting the actuation button 18 to rock only within the groove 24. The diameter of the guide pin 28 is smaller than the diameter of the hinge pins 20 to allow the actuator to be tilted sufficiently within the groove 24 to actuate the dome switch 6.