A modular assembly for a self-indexing computer pointing device

The present invention relates to pointing devices used in computers and the like.

Modern computer operating systems and graphics programs require a pointing device to control the position of the cursor on the computer display. For desktop PCs, the most successful pointing device is the "mouse". A mouse is a handheld object that moves on a flat surface near the keyboard and controls the movement of the cursor on a computer display. The direction and distance the mouse moves defines the direction and distance the cursor moves on the display. Traditional mice provide a rigid object that the user can move very accurately. For desktop computers, the mouse provides a satisfactory solution to the alignment problem. If the work environment is not wide enough to move the mouse and provide a path corresponding to the desired cursor movement on the display, the user simply picks up the mouse and recenters it in the workspace. Put in.

In the desktop PC market, mice provide a satisfactory solution to the problem of pointing devices, but similar successful devices are not available for portable and handheld computers. These computers are often used in environments that lack a sufficiently wide flat surface near a keyboard on which the mouse can be moved. Therefore, some other form of pointing device is used when using those computers in such an environment.

Pointing devices for use in those environments must solve the problem of quick and accurate cursor movement. In addition, the device must be able to operate in an intuitive way that an inexperienced user can understand, without a wealth of instructions. In addition, the pointing device must be operated in a limited working environment and fit within the computer's form factor or handheld device. Ultimately, it meets the usual constraints of low cost, low power output, and high reliability.

Currently, there are two main solutions to the problem of pointing devices on laptop computers, Synaptics' capacitive touchpad® and IBM's TrackPoint®. Other companies also manufacture variants of those devices with similar functionality. Both of these devices are far from satisfying the above requirements. TrackPoint® is a small button that is generally located in the center of a laptop keyboard. The button is moved in a manner similar to a "joystick" by applying a lateral force to the top of the button with a finger. Unfortunately, the button moves only a small amount, so the amount of movement of the button cannot be directly converted to the amount of movement of the cursor position on the computer display. Instead, the amount of movement of the button controls the direction and speed at which the cursor moves. The accuracy with which the user can position the cursor using this form of speed control is significantly less than achieved with conventional mice. This limitation is especially apparent for tasks that require small and accurate movements, such as those drawn by computer graphics programs.

A touchpad® is a rectangular blank pad with a side of 50-100 mm that is generally located in front of many laptop keyboards. The device detects the position of the finger on the surface of the rectangle with respect to the sides of the device. This detection is achieved by measuring the change in capacitance guided by the user's finger on a series of electrodes beneath an insulated low friction material.

Like the TrackPoint®, the Touchpad® lacks accuracy. It is inherently difficult to measure capacitance changes induced by users with unknown potentials to the circuit. Further, the area of contact with the user's finger is relatively large. Therefore, in order to accurately measure the position of the finger, the device must determine some parameter, such as the center in the contact area between the finger and the pad. Unfortunately, the size and shape of the contact area will vary depending on the pressure applied by the user. Therefore, such a determination is best with limited accuracy. In fact, the user cannot repeat and perform accurate actions.

If the user unknowingly touches the pad with a finger or wrist, the wrong signal can cause problems. On some devices, tapping the pad performs the traditional mouse "click" function. As a result, such inadvertent action between types can cause the cursor to jump to a new location or insert text into a new location during a typing operation.

A "pack" -based device in which the user moves with the user's finger provides a higher degree of accuracy because the position of the puck within the possible operating area can be accurately determined. In addition, the pack can be moved a much larger distance than the joystick used at TrackPoint®.

<p> Pack-based pointing devices provide more accurate input, but there is a unique problem of cleaning and replacing the pack. The puck needs to slide smoothly over the surface of the puck operating area using a low friction "touch" without letting dust get into the mechanism. In addition, if dust gets inside the mechanism, it is more difficult to clean the pack mechanism. Ultimately, the components of the pack are more easily damaged, so there is a need for a low-cost way to replace the main components.</p>

<p> The present invention includes a pointing device having a pack subassembly and a base subassembly. Pack subassemblies include movable packs that are restricted to move within the pack operating area. The pack subassembly includes a support member having an opening that defines a boundary with respect to the pack operating area. The base subassembly includes a base surface on which the pack moves, a position detector that measures the position of the pack within the pack operating area, and a mounting mechanism. The mounting mechanism connects the base subassembly to the pack subassembly so that the pack subassembly is reversibly separable from the base assembly. The base surface becomes accessible once the pack subassembly is separated from the base assembly. In one embodiment, the pack subassembly further comprises a restoring mechanism that returns the pack to a predetermined area of the pack operating area. In another embodiment, the support member also includes a first contact that couples with a corresponding second contact in the base subassembly to form an electrical connection between the pack and the base subassembly. The pack is preferably electrically connected to the first contact via a spring that returns the pack to a predetermined area of the pack operating area.</p>

How the present invention brings its benefits can be more easily understood by reference to FIGS. 1A-1B, which illustrate the pack-based pointing device 10. FIG. 1A is a plan view of the pointing device 10, and FIG. 1B is a cross-sectional view of the pointing device 10 along the line 1B-1B shown in FIG. 1A. The pointing device 10 includes a pack 11, which moves over the surface 12 of the substrate 15 within the pack operating area 19 in response to the lateral force applied to the pack 11. In general, the force is applied to the pack by the user's fingers, fingertips, thumb, thumb tip, and multiple fingers. Pack 11 includes a pressure sensing mechanism that measures the vertical force applied to the pack. In addition, the pointing device 10 includes a detection mechanism for determining the position of the pack 11 on the surface 12.

Generally, packs are used to control the position of the cursor on the display. When the user applies a vertical force greater than a predetermined threshold to the pack 11, any change in the position of the pack 11 on the surface 12 is transmitted to the host device on which the pointing device forms that portion. The repositioning is used to move the cursor on the display by the magnitude and direction of movement of the pack 11 while the vertical force is applied to the pack 11. .. That is, if the movement of the puck is characterized by the distance d and the direction defined by the angle φ on the pointing device, the movement of the cursor is characterized by the distance D and the direction defined by the angle φ on the display. Attached. The hardware driver in the host device usually sets the relationship between D and d.

When the user releases the pack 11 by releasing the user's finger 16, the pack 11 is returned to its center position by the spring 13 indicated by the reference number 13 that connects the pack to the side 14 of the pack operating area. Since the user's finger does not apply a force perpendicular to the pack 11 to the pack 11 while the pack returns, the position change associated with that return motion is not transmitted to the host device. This provides a convenient "recentering" function achieved in the mouse by lifting and repositioning the mouse in the center of the motion area. This is especially necessary for laptop computers, handheld devices, and other small devices with limited operating areas.

The pointing device brings many improvements over the traditional pointing devices included in laptop computers, but the pointing device requires regular cleaning. Dust and other deposits accumulate on the surface of the puck operating area and interfere with the smooth movement of the puck on that surface. In addition, it may damage the springs that position the pack within the pack operating area. Ultimately, it is advantageous to provide a design that can be easily customized to include a manufacturer's logo or a button array that is more ideally adapted for left-handed users.

The present invention overcomes these problems by constructing a pointing device utilizing two subassembly designs. Further refer to FIG. 2, which is a cross-sectional view of the pointing device 30 according to an embodiment of the present invention. The pointing device 30 includes a base subassembly 40 and a pack subassembly 50. The pack subassembly 50 includes a pack 51, a plate 52 having an opening 54 that defines the pack operating area, and a spring 55 that returns the pack 51 to a predetermined position in the pack operating area when the pack 51 is released. Including.

The base subassembly 40 includes a surface 45 on which the position sensor 41 is used to measure the position of the pack within the pack operating area. A protective layer (not shown) that electrically insulates the sensors from the pack preferably covers them. The base subassembly 40 also includes a controller that receives signals from the sensor 41 and calculates the position of the pack 51 from those signals. How to determine the position will be discussed in more detail below.

The base subassembly 40 also includes a movement stopper 46 for fixing the pack subassembly 50 within the base subassembly. The pack subassembly 50 is preferably placed so that it is fitted into the base subassembly 40. A spring, such as the spring 49, is used to hold the pack subassembly 50 against the lock 46. However, any mechanism that allows the base assembly 40 to be detached from the pack subassembly can be utilized without the use of special tools. For example, the pointing device of the present invention can utilize a plurality of screws to hold both the pack subassembly 50 and the base subassembly 40.

As pointed out earlier, pointing devices such as the pointing device 30 may collect dust or other deposits that may interfere with the smooth movement of the puck or puck position detection mechanism. Therefore, the pointing device of the present invention preferably allows the user to disassemble the pointing device and clean the pack and the underlying surface. In addition, a design that allows the user to easily replace the pack mechanism is preferred, as the springs and / or the components of the pack may fail due to wear or misuse. Ultimately, the manufacturer of a particular computer or other host device may incorporate a logo or other customized mark on the pack or surrounding plate. Therefore, a design that allows the pointing device to be manufactured with any one of a plurality of special pack subassemblies is advantageous.

In addition, the base subassembly 40 includes a plurality of connectors 47 coupled to the corresponding connectors 58 of the pack subassembly 40 for transferring signals from the pack 51 to the controller 42. The signal from the pack 51 is preferably connected to the connector 58 via one or more springs 55. The spring in question is either made from a conductor or has a conductor embedded or coated therein.

The position of the puck within the puck operating area is detected by any of the many methods. Generally, each method utilizes one or more components provided in the base assembly. One such position detection mechanism is illustrated in FIG. FIG. 3 is a plan view of the portion of the surface 12 shown in FIG. 1 in which the pack moves on the embodiment of the present invention. Surface 150 includes four electrodes, reference numbers 151-154, having terminals connected to external circuits. These terminals are omitted for simplicity in the figure. The pack has a bottom surface that includes the electrode 155, which is shown by the dotted line in the figure. Electrodes 151-155 are electrically isolated from others. For example, the electrode 155 is covered with a dielectric layer that provides the required insulation as the electrode 155 slides over the other electrodes. In short, the electrodes are patterned on the back side of the substrate on the surface indicated by reference numeral 150. This reduces the capacitance to the pack electrode, but is practical for substrates with a thickness of a few millimeters or less. The overlap of the electrodes 155 and each electrode 151-154 depends on the position of the pack with respect to the electrodes 151-154. The overlap between electrodes 155 and 151-154 is indicated by AD, respectively.

See further FIG. 4, which is a schematic diagram of an equivalent circuit for electrodes 151-155. The portion of the electrode 155 that overlaps the electrode 151 forms a parallel plate capacitor having a capacitance proportional to the overlap A. Similarly, the portion of the electrode 155 that overlaps with the electrode 152 forms a parallel plate capacitor having a capacitance proportional to the overlap B, and so on. Since all of the capacitors share a portion of the electrode 155, the equivalent circuit consists of four capacitors connected to the common electrode indicated by reference numeral 158. This electrode is exactly the electrode 155. Therefore, the position of the electrode 155 with respect to the electrodes 151-154 can be defined by measuring the capacitance between the electrodes 155 and each of the electrodes 151-154. This demarcation is made by the controller 159, which is part of the pointing device or part of the host device to which the pointing device is connected.

In embodiments where the pack operating area is substantially larger than the diameter of the pack, more than four electrodes can be placed on the substrate. A measurement of the capacitance between each of those electrodes and the pack can be used to determine the position of the pack, as described above.

Further, the position of the pack in the pack operating region can be confirmed by using an optical sensor as used in a conventional optical mouse. See further in FIG. 5, which illustrates such a detection mechanism. In this embodiment, the bottom surface 84 of the pack 82 is illuminated by an optical mouse sensor 83 located directly below the surface 81 of the pack operating area. Optical mouse sensors are well known in the art and are therefore not discussed in detail herein. For the purposes of this paper, it is sufficient to point out that the optical mouse sensor 83 has a lighting system that illuminates the bottom surface of the pack 82 and an image sensor that forms an image of the illuminated surface portion. The imaging system compares the continuous images of the bottom surface and defines the size and direction in which the puck moves between the images.

Previous examples of suitable position detection mechanisms are provided by way of example. However, from the previous discussion, it is clear that a large number of position measuring mechanisms are available without departing from the art of the present invention.

The above embodiments of the present invention utilize a special mounting mechanism that connects the pack subassembly to the base subassembly. However, many other mounting mechanisms can be utilized without departing from the present invention. Further refer to FIGS. 6 and 7, which illustrate other embodiments of the pointing device of the present invention. FIG. 6 is a plan view of the pointing device 200, and FIG. 7 is a cross-sectional view of the pointing device 200 along line 7-7 of FIG. The pointing device 200 is composed of a pack subassembly 210 and a base subassembly 220. The base assembly 220 includes two slots 221 which are sized to allow the corresponding tabs indicated by reference number 212 to pass through. The pack subassembly 210 is attached to the base subassembly by aligning the tabs with the slots. As the tab passes under the top surface of the base assembly, the pack subassembly is rotated until the tab engages the corresponding receptacle.

The electrical connection between the pack subassembly 210 and the base subassembly 220 is formed through the contacts of the tabs that engage the corresponding contacts in the slot. Illustrative contact pairs are shown by reference numbers 215 and 225. These contacts form a connection to the electrodes in pack 223 up to controller 235 in base subassembly 220. Further, the controller 235 is connected to the position detection electrode indicated by reference numeral 222.

The mounting mechanisms shown in Figures 6 and 7 do not require any tools. The user can remove the pack subassembly by simply twisting the pack subassembly until the tab is aligned with the slot. Appropriate recesses or protrusions can be provided on the surface of the pack subassembly 210 to assist the user in manipulating the subassembly. Therefore, the user can easily remove the pack assembly for cleaning and / or replacement. Removing the pack subassembly allows cleaning of any electrodes on the base subassembly and the bottom of the pack itself.

The present invention is particularly well suited for implementation on laptop computers and other host devices with limited space for pointing devices. Further refer to FIGS. 8 and 9 illustrating a laptop computer having a pointing device according to an embodiment of the present invention. FIG. 8 is a plan view of the laptop computer, and FIG. 9 is a sectional view taken along line 9-9 of FIG. The display is omitted from the figure for the sake of simplicity. The pointing device 310 is preferably located adjacent to the keyboard 320 of the laptop 300. The base subassembly 330 is secured to the laptop and attached to the surface wall adjacent to the keyboard, providing an overall thin laptop form factor. Alternatively, the base subassembly 330 can be formed by pouring it onto the surface of a laptop computer. In one embodiment, the base subassembly is attached to its surface in such a way as to prevent the base subassembly from being removed by the user. In this embodiment, the connection between the pointing device and the laptop is provided under the base subassembly. Illustrative contacts for making these connections are indicated by reference numbers 360 and 361. This arrangement seals the base subassembly against the laptop computer in such a way as to prevent liquids or deposits from entering the laptop computer through the pointing device.

The pack subassembly is attached to the base subassembly in a manner similar to that described above. This mounting mechanism allows the pack subassembly to be easily removed by the user for cleaning and / or replacement. The pack subassembly includes a pack 341, a spring 342, and an upper plate 343. The top plate 343 has a hole that defines the pack operating area and a mounting mechanism for connecting the pack subassembly to the base subassembly.

The above embodiments of the present invention have described pointing devices used with laptop computers. However, it is clear from the previous discussion that the present invention is available in many different data entry environments. For example, the pointing device of the present invention can be a stand-alone pointing device that replaces a conventional mouse. Similarly, the pointing device of the present invention can be used as a pointing device for a PDA or a mobile phone and can be selected from the menu of those devices.

Various modifications to the present invention will be apparent to those skilled in the art from the above detailed description and accompanying drawings. Therefore, the present invention is limited only by the description of the appended claims.

<figref num="1A">The plan view of the pointing device based on a pack is shown.</figref><figref num="1B">It is a figure which shows the cross section of the pointing device shown in FIG. 1A along the line 1B-1B.</figref><figref num="2">It is a figure which shows the cross section of the pointing device by one Embodiment of this invention.</figref><figref num="3">In one embodiment of the present invention, it is a plan view of the portion of the surface 12 shown in FIG. 1 in which the pack moves.</figref><figref num="4">It is the schematic of the equivalent circuit about electrodes 151-155.</figref><figref num="5">FIG. 5 illustrates a detection system that utilizes an optical sensor to define the position of the puck within the puck operating area.</figref><figref num="6">It is a top view which shows the other embodiment of the pointing device by this invention.</figref><figref num="7">It is a figure which shows the cross section of the pointing device shown in FIG. 6 along the line 7-7.</figref><figref num="8">FIG. 5 is a plan view of a laptop computer having a pointing device according to an embodiment of the present invention.</figref><figref num="9">It is a figure which shows the cross section of the laptop computer shown in FIG. 8 along line 9-9.</figref>