The present encoder-switch assemblies are particularly well adapted for use in mobile phones or, generally, in any type of electronic equipment that will benefit from the very small outer dimensions and simple construction of the present en- coder-switch assemblies.

BACKGROUND OF THE INVENTION Electromechanical roller-key assemblies which may be used to generate digital control signals in response to a rotation of a roller or tuning knob and to generate an actuator switch signal in response to a depression of the roller are known from e. g. mobile phones. However, the mechanical constructions of these known devi- ces have certain drawbacks due to a large number of miniature movable and sta- tionary parts, often including a tiny detent spring element. This large number of separate parts requires a quite complex and labour intensive assembly procedure to assure that all parts are carefully aligned with respect to each other.

Electromechanical roller-key assemblies are often used to navigate in menus on an electric display of an apparatus. The number and the complexity of functions require that the navigation means can operate in tables and extended menu structures.

Accordingly, there is a need for an encoder-switch assembly of simplified con- struction with fewer parts than prior art assemblies so as to simplify the assembly procedure, reduce the assembly time and, consequently, lower the costs of inte- grating such encoder-switch assemblies in today's mobile phones and similar compact electronic equipment. Also, there is a need for an encoder-switch assem- bly, which provides extended navigation possibilities.

SUMMARY OF THE INVENTION It is an object of the invention to provide an electromechanical roller-key assembly of simple and robust construction which assembly may be integrated in electronic equipment and generate digital control signals in response to the instantaneous change in angular position of a user operated roller.

It is also an object of the invention to provide an electromechanical roller-key as- sembly suitable for being manufactured with very small outer dimensions, since such miniaturisation is a key requirement for applications such as hearing aids, compact mobile phones pagers, medical dispensing devices and similar handheld or body-worn devices, etc.

It is further an object of the invention to provide an electromechanical roller-key assembly comprising fewer and simpler mechanical parts compared to prior art roller-key assemblies, thereby making the present electromechanical roller-key assembly suitable for a simplified and automated factory assembly.

It is a still further object of the invention to provide an electromechanical roller-key assembly which in addition to the signals representing the rotation of the roller key provides switch signal outputs corresponding to at least four different logic states.

It is a still further object of the invention to provide methods for navigating and se- lecting items in tables and menus on an electronic display using a single roller key.

In a first aspect, the present invention provides a roller-key assembly, which is of a specific type comprising: -a carrier, -a roller member supported by the carrier and being rotatably mounted in rela- tion to the carrier, -a coding member engaging the roller member in a manner so as to rotate when the roller member rotates, -the carrier being mounted in a supporting structure and being at least partly displaceable relative to the supporting structure so as to render the roller member displaceable from an initial position to a selected displaced position out of at least two predetermined displaced positions, -means for detecting rotation of the coding member in relation to the supporting structure, -means for generating a return spring force that returns the roller member to the initial position from the selected displaced position, and -switching means being adapted to indicate the selected displaced position of the roller member.

The switching means typically comprises at least two separate switching means such as two actuator contacts, wherein the first is adapted to generate a first switch signal indicating that the roller member is in a first predetermined position, and the second is adapted to generate a second switch signal indicating that the roller member is in a second predetermined position. Optionally, the roller member is furthermore displaceable to a third predetermined displaced position. In this case, the switching means may further comprise a third switching means adapted to generate a third switch signal indicating that the roller member is in the third predetermined position. Alternatively the third predetermined displaced position of the roller member is indicated by a combination of the first and second switch sig- nals.

Preferably the selected displaced position is chosen by applying a predetermined force to an associated part of the roller member: -the first predetermined displaced position is selected by applying the prede- termined force to a first end part of the roller member, -the second predetermined displaced position is selected by applying the pre- determined force to a second end part of the roller member, and -if the roller member is furthermore displaceable to a third predetermined dis- placed position, the third displaced position is selected by applying the prede- termined force to a substantially middle part of the roller member.

The carrier may comprise a first and a second part, where the first part is substan- tially rigidly connected to the frame and the second part is adapted to support the roller member and is displaceable relative to the first part of the carrier. Thereby, a torque spring force are constituted by the carrier so as to return the second part to a relaxed position when the second part is displaced to a relative to the first part.

In this case, the carrier is preferably made from a plate-shaped resilient material.

One or more indentations may separate first and second parts of the carrier in or- der to provide regions with a higher resiliency than regions of the carrier abutting the one or more indentations.

When the roller member is displaced to one of the predetermined displaced posi- tions, it is preferred that the carrier actuates the switching means, e. g. by protru- sions on the second part of the carrier. Alternatively the roller member is adapted to actuate the switching means when it is displaced.

The switching means may comprise one or several membrane switches. Optional- ly, such membrane switches may comprise a resilient material and be adapted to provide a return spring force to the roller member or the carrier when the roller member and the carrier are displaced towards the switching means. Alternatively, the resilient material may not form part of the switching means but be arranged between the switching means and the roller member so as to provide the return

spring force to the roller member or the carrier when the roller member and the carrier are displaced towards the switching means. The resilient material may be any material selected from the group of: rubber, plastic, foam, metal, metal alloys.

The supporting structure of the roller-key assembly according to the present in- vention may constitute a frame supporting at least part of the carrier.

In order to transmit the rotation from the roller member to the coding member, the roller-key assembly may comprise a shaft providing a substantially rotationally rigid connection between the roller member and the coding member. The shaft is mounted so as to allow different parts of the roller member to be displaced in rela- tion to the coding member along directions substantially perpendicular to the axis of rotation of the roller member. Preferably, the roller member comprises a bore wherein at least part of the shaft is positioned.

The encoder part, that is coding member and the means for detecting rotation of the coding member, may operate according to magnetic, optical and/or electrome- chanical principles. In order to protect the mechanical, electrical, magnetic or optic components from contamination, the encoder part is preferably arranged inside a substantially moisture-or watertight cavity, parts of which is formed in the frame.

Also, in order to protect the mechanical and electric parts of the switching means and the other components of the apparatus holding the roller-key assembly, the roller-key assembly may further comprise a sealing foil arranged between the switching means and the roller member so as to separate the switching means from the roller member by a substantially moisture-or watertight layer. The sup- porting structure and the sealing foil, said well having an opening arranged oppo- sitely to the sealing foil may form a substantially moisture-or watertight well wherein the roller member and preferably the carrier is mounted. The roller-key assembly may further comprise means for draining liquids and small particles from within the well, e. g. in the form of a pipe or hose with a first opening positioned within the well.

In another embodiment of the present invention, a hand-held electronic apparatus comprising the above described roller-key assembly is provided. Such hand-held electronic apparatus may be selected from the group of: mobile phones, remote controls, pagers, handheld computers, discmans, MP3-mans, GPS navigators or personal digital assistant.

The hand-held electronic apparatus may further comprise a controller operational- ly connected to the switching means of the roller-key assembly and adapted to re- ceive the first and second switch signals. The controller is adapted to generate a first output if the first switch signal precedes the second switch signal with more than a first delay time, At1, and a second output if the second switch signal prece- des the first switch signal with more than At. Thereby the first output from the controller indicates that the first predetermined displaced position was selected and the second output indicates that the second predetermined displaced position was selected. The output from the controller is preferably a digital output.

If the roller member is furthermore displaceable to a third predetermined displa- ced position, and if this third displaced position is indicated by a combination of the first and second switch signals, the controller is further adapted to generate a third output if the time interval between the first switch signal and the second switch signal is less than a second delay time, At2. Thereby, the third output indi- cates that the third predetermined displaced position was selected.

Preferably the value of At1 equals the value of At2, and preferably the time interval At1 is larger than 10 ms or 25 ms, such as larger than 50 ms or 100 ms. Accor- dingly, the time interval At2 is preferably smaller than 100 ms or 50 ms, such as smaller than 25 ms or 10 ms.

In a second aspect, the present invention provides a method of navigating on an electronic display displaying one or more items. Such items may be tables, cells, menus, sub-menus, pop-up menus, buttons etc. The navigation takes place by

moving an indicator between items; the indicator may be change of colour of the item, a cursor, a pointer, a frame around the item or any visual or acoustic feature.

The method of navigating on an electronic display according to the second aspect comprises the steps of: -providing a rotatably mounted roller member displaceable from an initial posi- tion to a selected displaced position of at least two predetermined displaced positions, -rotating the roller member in a first or a second direction, -detecting rotation of a coding member engaging the roller member in a manner so as to rotate when the roller member rotates, -moving the indicator between items in a first or second direction in response to the detected rotation of the roller member, -applying a predetermined force to a first or second part of the roller member, -detecting the displaced position of the roller member, and -moving the indicator between items in a third or fourth direction in response to the selected displaced position of the roller member.

Preferably, the present invention further provides a method of selecting an item on an electronic display. In this case, the roller member is furthermore displaceable to a third predetermined displaced position. The method comprises the steps of : -moving the indicator to the item to be selected according to the above- mentioned method, -applying a predetermined force to a middle part of the roller member, -detecting the displaced position of the roller member, and -selecting the item.

In a third aspect, the present invention provides a method of selecting an option on an electronic display displaying one or more items, at least one of which com- prises two options. The method comprises the steps of:

-providing a rotatably mounted roller member displaceable from an initial posi- tion to a selected displaced position of at least two predetermined displaced positions, -rotating the roller member in a first or a second direction, -detecting rotation of a coding member engaging the roller member in a manner so as to rotate when the roller member rotates, -moving between items in the menu in a first or second direction in response to the detected rotation of the roller member, -applying a predetermined force to a first or second part of the roller member, -detecting the displaced position of the roller member, and -selecting a first or a second option in response to the selected displaced position of the roller member.

BRIEF DESCRIPTION OF THE DRAWINGS Hereunder, preferred embodiments of electromechanical roller-key assemblies according to the invention are described with reference to the drawings, wherein Fig. 1 shows a cross-sectional view of a first embodiment of an electromechanical roller-key assembly according to the present invention, Fig. 2 is an illustration of an electronic display with menus and a table, Fig. 3 shows a perspective view of various elements of the first embodiment of an electromechanical roller-key assembly according to the present invention, and Fig. 4 shows a perspective view of the first embodiment of the electromechanical roller-key.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Figures 1 shows an electromechanical roller-key assembly according to a first preferred embodiment of the invention. A plastic moulded roller member 2 is ro- tatably mounted in a carrier 4, which is displaceably mounted in a supporting frame 6. In principle, the moulded roller member 2 may take any form. Preferably, the centre section of the roller member (at arrow 12) has a smaller diameter than the end sections of the roller member (at arrows 11 and 13). Means for detecting the rotation of the roller member is connected to the roller member 2. A detent spring element is also mounted on the frame and returns the roller member to a relaxed position when it is vertically depressed. The mounting is so that when ap- plying a force to the roller member at either end and perpendicular to the axis of the roller member (according to the arrows 11 or 13), the same end of the roller member will be displaced leaving the opposite end of the roller member in its re- laxed position. Applying a force to the centre of the roller member and perpen- dicular to the axis of the roller member (according to the arrow 12) will displace the entire roller member.

Two actuator contacts (8 and 9) are positioned below the roller member and de- pressing corresponding parts of the roller member activates either or both con- tacts.

It is an essential aspect of the present invention that the roller key in excess of the navigation possibilities in rolling or scrolling, provides switch signal outputs cor- responding to at least four different logic states, as illustrated in Table 1 below.

This is achieved by having at least two actuator contacts, which can be depressed individually or simultaneously by depressing corresponding parts of the roller member. Depressed Contact 8 Contact 9 None 1 1 Leftend 0 1 Rightend 1 0 Middle part 0 0

Table 1 In order to determine the logic state of the switch signal output, it is necessary to be able to separate an output where both contacts 8 and 9 are activated, from two succeeding outputs corresponding to activation of the left contact 8 and the right contact 9 respectively. This can be solved by setting up a first time-interval At, and a second time-interval At2. If a signal from contact 8, S8, and a signal from contact 9, S9, are temporally separated by more than Atr, then the signals are conceived as two individual signals from two succeeding depressions of the roller member. If however two signals S8 and S9 are temporally separated by less than At2, then the signals are conceived as a combination S8 + S9 from a single depression of the middle part of the roller member. Preferably the time-intervals At, and At2 are the same. A control unit such as a microprocessor receiving the signals from con- tacts 8 and 9 can perform this determination, and generate digital outputs corre- sponding to the four logic states illustrated in Table 1.

Alternatively the same four logic states can be obtained using a combination of three contacts instead of two.

Figure 3 shows various elements of an electromechanical roller-key assembly ac- cording to the first preferred embodiment of the invention. A roller member 2 is rotatably mounted in a carrier 4. Preferably, the roller member 2 comprises a de- tent-bearing plug 2b and a soft rubber surface part 2a in order to provide traction for rotating the roller member with a finger. A first end surface 3 of the roller mem- ber 2 contains a corrugated groove adapted to contact a detent spring protrusion in the metal carrier 4 in order to create a tactile feedback when the roller member is rotated. A first part 4c of the carrier is rigidly mounted in a supporting structure

such as the frame 6, or any casing or housing of an apparatus in which the roller key assembly is to be integrated. Actuator contacts 8 and 9 are positioned below the roller member and the frame. The contacts 8 and 9 are preferably membrane switches.

Preferably, a flexible/bendable shaft 36 transmits the rotation of the roller member 2 to a disc-shaped coding member 10. The coding member is adapted to receive the end part of the flexible/bendable shaft 36, which extends from the roller mem- ber 2 through a second part 4a of the carrier. Alternatively, the coding member engages the roller member directly, and may even be an integrated part of the roller member 2. Scanning means 40 detects the rotation of the coding member and provides output signals characterising the rotation.

As can be seen in Figure 1, the flexible/bendable shaft 36 extends off-axis in the relaxed position of the roller member. Thereby the roller member has a longer idling when the roller member is vertically depressed. Moreover, the shaft is rota- tionally rigid in both the roller member 2 and the coding member 10, but is allowed to pivot in the mountings when the roller member is depressed. The coding mem- ber 36 (including shaft) and the detent-bearing plug 2b are preferably moulded in a low friction plastic resin.

The carrier 4 is preferably manufactured in a single piece of U-bend plate-shaped metal. The carrier is divided into a first part 4c rigidly mounted in the supporting frame 6 and two second parts (4a and 4b) adapted to support the roller member 2 at its end surfaces. A mechanical connection in the form of a crossbar or a shaft can be added between the two second parts 4a and 4b of the metal carrier after it has been bend into the U-shape, thereby providing a carrier of improved mechani- cal stability.

Utilising an insert moulding process, two plastic bearing elements 5 are attached to the second parts of the metal carrier. The plastic bearing elements are utilised to mount the roller member 2 in a precise predetermined and rotatably manner relative to the metal carrier 4.

By providing two indentations in the metal carrier 4, the second parts 4a and 4b are made displaceable in relation to the first part 4c. Accordingly, when the first part 4c is rigidly mounted in a supporting structure and a force is applied to the roller member 2, one or both of the second parts is displaced from a relaxed posi- tion to a displaced position depending of the point of action of the force. When displaced, a torsion spring force is created in the carrier for returning the second part (s), and thereby the roller member, to its relaxed position, when the applied force is removed. Hence, the carrier itself functions as a detent spring so that there is no need for a separate spring element. Furthermore, the spring and dis- placing feature of this type of carrier is not liable to be obstructed by dirt or small particles. Another advantage of the metal carrier is it may further act as a de- coupling element of electrostatic charge that may build up on the roller member.

Optionally, the displacement of one or both of the second parts may bring protru- sions 7, which is integrated with the second parts of the metal carrier 4, in contact with one or both actuator contacts 8 or 9, arranged on e. g. a printed circuit board and positioned below the frame 6. Alternatively, the surface part of the roller member is adapted to actuate contacts 8 or 9 when depressed, e. g. by providing moulded protrusions on the roller member.

In another embodiment, the return spring force on the roller member is provided by means of a resilient material arranged below the roller member without suppor- ting it. The resilient may be in the form of a pad, a membrane or a bulge providing a return spring force when depressed. The material in such pad, membrane or bulge can be rubber, plastic, foam, gel, silicone, metal, metal alloys or other. In this case the carrier holding the roller member needs only to be displaceable in relation to the frame, alternatively, the roller member can be mounted directly, and displaceable, in the frame.

The coding member 36 is preferably formed by pressing a metal disc 10 with a number of holes or notches onto a number of corresponding protrusions moulded in coding member 36. The holes (or notches) and protrusions may be arranged along a substantially circular surface path. Accordingly, the coding member 36

provides an encoding disk comprising a number of intermittently arranged con- ducting and non-conducting pads. By providing the protrusions on the coding member 36 with substantially the same height as the thickness of the metal disc 10, a plane surface of the coding member may be provided and contacted by the at least three contact members of the scanning means 40. Thereby, during rota- tion of the coding member, electrical contact is intermittently established between the three contact members, and pulse trains of differing phase with respect to each other may be provided at the leg parts.

The rotation of the roller member can be detected other types of coding means than the one presented above. An optical encoder (not shown) can be realised by providing an encoder disc with variably spaced or variably sized apertures toge- ther with an LED and a photodiode. Positioning the photodiode so as to receive light from the LED through apertures in the encoder disc, the rotation speed and direction of the coding member can be determined from the pulse trains emitted by the photodiode. By using a similar scheme a magnetic encoder can be utilised.

It is desirable to protect electronic and mechanical parts from moisture and exter- nal contamination. Preferably only the roller member, the carrier and the upper rim of the frame are exposed. In the first embodiment, shown in parts in Figure 3 and assembled in Figure 4, the roller member 2 and the carrier 4 can be mounted in a substantially moisture-or watertight well 47 separating them from the other parts of the assembly.

The coding member 10 and scanning means 40 in Figure 3 are preferably arran- ged in a closed cavity 45 for protection against moisture, small particles and other contamination. In Figure 3, a cavity is constituted by a passage 44 formed in the frame 6 with one end closed by a lid 42. The lid 42 can be snap-fitted to the frame.

Furthermore, an inner surface in the lid 42 can be provided with a projection abut- ting against each of the contact members of the scanning means to provide a contact or bias force between the contact members and the encoding disc.

The actuator contacts 8 and 9 are preferably protected against contamination. By abutting the lower rim of the frame 6 to a layer of sealing foil 46 of substantially moisture-or watertight material, the well 47 is formed by the sealing foil 46, the frame 6 and the sealed connection to the closed cavity 45. The sealing foil layer must be flexible for allowing the contacts to be actuated by the carrier or roller member. Optionally the layer is hard with resilient areas over the contacts.

Optionally the well 47 is connected to a drain (not shown) for draining moisture and dirt from the well. The drain can be a pipe or hose with a first opening forming a drain-hole from the well and the second end forming an outlet at the opposite side (or elsewhere) on the apparatus.

The output signals provided by the contacts 8 and 9 and the rotation detection means is in a preferred embodiment used to navigate between and select items in menus and tables on an electronic display 16, as shown in Figure 2. According to Figure 2, the electronic display displays three main areas, a table 17 and two menus 18 and 19, each comprising one or more items, such as a cell 20 in the ta- ble 17 or a menu option 21 in the menus 18 and 19. Each item can be assigned as active by moving an indicator 22 to the item. An active item can e. g. lead to other items as indicated by arrows 25 and 27, comprise selectable buttons 26 and 28, activate pop-up menus, or be adapted to receive inputs as for the cell 20. In Figure 2 the indicator 22 is change of colour of the item, it could also be accomplished by a cursor, a pointer, a frame around the item or any visual or acoustic feature.

The indicator 22 may be moved to other areas or items e. g. up or down in 17 and 18, by rotating the roller member in the roller key assembly. The indicator may also be moved to other areas or items by depressing a part of the roller member corresponding to the desired direction of movement, e. g. left or right in 17 and 19.

To move left, the left end part of the roller member is depressed according to the arrow 11 on Figure 1; to move right, the right end part is depressed according to the arrow 13 on Figure 1.

In figure 2, some items comprise other menu options 26 and 28, such as selec- table buttons. In a preferred embodiment, such items can be selected by making one of the items the active item by pressing left for 26 or right for 28, and there- after select the option by pressing the middle part of the roller member. Alternat- vely, if there is only two options to chose between, the options can be selected di- rectly by pressing left for selecting 26 or right for selecting 28. Also, in the table 17 a cell can be selected simply my moving the indicator to the cell. Alternatively, items can be selected by voice activation or a touch pen if the indicator is already moved to the item.

As described in relation to Figure 2, the roller key assembly according to the pres- ent invention provides a major advantage in that the rolling and the switch signal outputs provide possibilities for two-dimensional navigation. Furthermore, the roller key assembly provides switch signals for selecting active items.