GB2445615A

GB2445615A - Digital pen adapter

Info

Publication number: GB2445615A
Application number: GB0700462A
Authority: GB
Inventors: Mark Peter Bird; James Gardiner
Original assignee: STELJES Ltd
Current assignee: STELJES Ltd
Priority date: 2007-01-10
Filing date: 2007-01-10
Publication date: 2008-07-16
Anticipated expiration: 2027-01-10
Also published as: GB2445615B; GB0700462D0

Abstract

A digital pen adapter 602 that can be attached to a digital pen 600 allows the functionality of the digital pen to be expanded. The digital pen has a writing tip and the adapter has a writing tip 604 (e.g. similar to a marker pen writing tip) that is exposed for contact with a writing surface (e.g. a flip chart) in place of the writing tip of the digital pen. The digital pen provides an imaging system adapted to image a portion of the writing surface located at or at a predetermined position from the tip of the digital pen writing tip when the digital pen writing tip is in contact with the writing surface.

Description

PEN ADAPTER AND ACCESSORIES

The present invention relates to an adapter for a pen, particularly for a digital pen, and accessories therefore.

The present invention also relates to a method of operating such an adapter, in combination with a digital pen.

It is known to use a writing tablet and a stylus for inputting hand written data into a computer or other information processing system. The tablet typically has a complex structure, since it is required to co-operate with the stylus to determine electronically to relative position of the stylus on the tablet. Furthermore, the movement of the stylus over the surface of the tablet, whilst providing data for input into an associated computer, does not provide any change in the surface of the tablet itself that is visible to the user.

WO 97/22959 discloses an apparatus for absolute optical position determination that is radically different from the tablet and stylus arrangement outlined above. Rather than requiring a tablet, WO 97/22959 discloses the use of specially printed paper and a pen that, as well as writing on the paper, can determine the position of the pen with respect to the paper and can therefore generate data corresponding to the markings of the pen on the paper. The pen includes a stylus or nib that contacts the paper to activate the optical detection system of the pen. The pen communicates with other devices via a wireless transceiver.

WO 00/72230 discloses a similar system to WO 97/22959 except that the pen of WO 00/72230 includes a motion sensing device such as an accelerometer to periodically sample the acceleration of the pen so as to generate movement data. It is intended that the system of WO 00/72230 is used with paper printed on a netpage printer, so that a user can interact with a netpage to fill in forms, for example.

The technology of WO 97/22959 has been developed by the company Anoto AB, Sweden. Anoto have produced a proprietary pattern of very small dots printed on paper. The pattern of dots on white paper is perceived by the unaided human eye as having a slightly off-white colour. The pattern of dots is such that only a very small area of the total pattern needs to be imaged in order for there to be a unique determination of the position in the full pattern. The total area of the full pattern is about 60 million square kilometres.

The pattern of dots interacts with the imaging device of suitable digital pens to allow information coming from the pen to be processed into signals representing functionality, writing and drawing.

The Anoto pattern provides small dots with a nominal spacing of 0.3 mm (0.01 inch) . These dots are slightly displaced from a grid structure to form the proprietary Anoto pattern.

When writing with a digital pen on a paper printed with the pattern, digital snapshots of the pattern are typically taken with a rate of more than 50 per second. Every snapshot contains enough information to make a calculation of the exact position of the pen. The intelligence in the paper, derived from the pattern, makes it possible to perform operations by ticking a box with the pen, for example to send a form.

One of the main advantages of the Anoto system is that the user is able to use the pen in a normal way, writing or drawing on paper so as to have a hard copy of the writing or drawing.

WO 2006/049573 discloses a digital pen suitable for use with Anoto pattern paper. This document explains that the pen captures a series of images of the surface being written or drawn on. These images are processed to generate a sequence of data items, typically one position for each image. These positions are then continuously input to an offline process or an online process, dependent on a selection made by the user. In the offline process, the data items are stored in a persistent memory in the pen. In the online process, the positions are buffered in a temporary memory before being output from the pen.

WO 2006/049573 explains that the pen may store one or more templates that define how the pen is to operate on the information that is recorded from different parts (such as functional areas) of the position-coding pattern. Such functional areas may be denoted as "pidgets". One suggested function for a pidget in WO 2006/049573 is a streaming attribute, which indicates to the pen that the recorded positions falling within the area of interest should be output in real time to an external device. However, the default operation of the device of WO 2006/049573 is to store the recorded positions in the pen memory as offline data, these only being downloaded to an external device at a later time.

Various companies other than Anoto AB provide digital pens for use with Anoto functional paper. One such company is Logitech Europe S.A., Switzerland. Logitech's published patent application WO 2005/010634 describes a digital pen that is capable not only of capturing normal pen strokes (such as handwriting and drawings) but is also capable of carrying out functional operations on such strokes (e.g. highlighting) by operation of function control buttons on the pen. The content of WO 2005/010634 is hereby incorporated by reference in its entirety.

The pen of Wa 2005/010634 includes a pen barrel having a grip area, a pen tip and a lens for the imaging components held within the pen. The pen has an ink cartridge so that the user can see the characters or shapes made on the paper by the pen tip. Pressure between the tip and a paper writing surface is detected by the pen, which activates the pen to detect and store the pen strokes made by the user.

Various communications interfaces are possible for the devices set out in WO 2006/049573 and WO 2005/010634, such as USB or RS232 (wired communication) , or radio transmission, ultrasound transmission, infrared transmission, inductive coupling, etc. (wireless communication) One particular short-range wireless communication protocol is widely known as Bluetooth (registered trade mark) Bluetooth technology operates in the unlicensed industrial, scientific and medical (ISM) band at 2.4 to 2.485 GHz, using a spread spectrum, frequency hopping, full-duplex signal at a nominal rate of 1600 hops/sec. The 2.4 GHz ISM band is available and unlicensed in most countries. Bluetooth is also known as IEEE 802.15.1. The core specification (Core Specification v2.0 + EDR, published 4 November 2004) for Bluetooth is available at http://www.bluetooth.com. The content of this core specification is hereby incorporated by reference in its entirety.

WO 2005/010634 suggests that the digital pen described therein can communicate with a dock via Bluetooth. This occurs when the pen is located at the dock, and is typically an off line dump of data from the pen to an information processing device (such as a personal computer) via the dock.

The present inventors have realised that existing digital pens form a useful basis on which different writing instruments can be based.

Accordingly, in a first aspect, the present invention provides a digital pen adapter that is attachable to a digital pen having a digital pen writing tip, the adapter having an adapter writing tip exposable for contact with a writing surface in place of the digital pen writing tip.

In a modification of the first aspect, the present invention provides a digital pen adapter that is attachable to a digital pen in place of a digital pen writing tip, the adapter having an adapter writing tip exposable for contact with a writing surface in place of the digital pen writing tip.

In a second aspect, the present invention provides a kit of a digital pen and a digital pen adapter, the adapter being attachable to the digital pen, the digital pen having a digital pen writing tip, the adapter having an adapter writing tip exposable for contact with a writing surface in place of the digital pen writing point.

Preferably, the kit includes a position-coding writing surface.

In a third aspect, the present invention provides a kit of a digital pen adapter according to the first aspect and a position-coding writing surface.

In a fourth aspect, the present invention provides a kit of two or more digital pen adapters according to the first aspect, each digital pen adapter corresponding to a different writing colour.

In a fifth aspect, the present invention provides a method of operating a digital pen adapter, the adapter being according to the first aspect, and the method including the steps of attaching the adapter to a digital pen and applying pen strokes to a writing surface using the adapter writing tip in place of the digital pen writing tip.

In a sixth aspect, the present invention provides an adapter dock for receiving a plurality of digital pen adapters according to the first aspect.

The adapter dock may be provided with corresponding digital pen adapters and optionally also with one or more corresponding digital pens.

The adapter dock may be attachable to, or may form part of an apparatus providing a writing surface for the digital pen and/or the adapter. The apparatus may be free-standing, in the style of a flip-chart stand or similar.

Preferred and/or optional features will now be set out.

These are applicable individually or in any combination with each other with any aspect or modified aspect of the invention unless the context demands otherwise. Furthermore, preferably any of the aspects or modified aspects of the invention are combinable with each other and in any combination unless the context demands otherwise.

The invention is preferably intended for use with a position-coding writing surface. Particularly (but not exclusively) preferred is a position-coding paper. Such paper may have a printed pattern of small dots that are substantially not discernible by the naked human eye in normal operation. The dots may be arranged in a unique pattern, such as the Anoto pattern discussed above.

Preferably, the digital pen includes an imaging system. The imaging system may be adapted to image a portion of the writing surface located at or at a predetermined position from the tip of the digital pen writing tip when the digital pen writing tip is in contact with the writing surface. The digital pen may include contact-detecting means for detecting contact between the digital pen and a surface such as a writing surface.

It is preferred of course that the field of view of the imaging system towards the digital pen tip and/or the writing surface is substantially unhindered. Typically, this is achieved in the digital pen by providing the digital pen writing tip at the free end of an overhang located above the optical input aperture of the imaging system (e.g. a lens may be located at this aperture) Preferably, the digital pen includes processing means for processing data from the imaging system to provide processed data corresponding to pen stroke positions. The digital pen may also include memory means for buffering and/or storing said data from the imaging system and/or said processed data.

The digital pen may also include conimuriication means for transferring said data to an external device such as a dock, computer, PDA or mobile telephone. Said communication means may be adapted to communicate with the external device via wired or, more preferably, wireless communication.

It is particularly preferred that the adapter provides the digital pen with additional functionality. Most preferred here is that, when the adapter writing tip is in contact with the writing surface, it provides a thicker mark on the writing surface than does the digital pen writing tip when the digital pen writing tip is contact with the writing surface. In effect, what is provided here is preferably a marker pen adapter for the digital pen.

Preferably the adapter writing tip provides a line thickness on the writing surface that is at least two times (and preferably at least five times or perhaps at least ten times) the thickness of the line provided by the digital pen writing tip in a single stroke. Typically the profile of the adapter writing tip is substantially bullet-shaped. The maximum thickness of the adapter writing tip (i.e. the thickness of the thickest part of the exposed writing tip) may be at least 2 mm, at least 3 mm, at least 4 mm or at least 5 mm. Thicker writing tips may be used suitable for their intended purpose. Also, the writing tip may be asymmetric about its principal axis. For example, the writing tip may have a thickness broader than its width.

Preferably the adapter writing tip is a felt writing tip.

The adapter may include an ink reservoir in fluid communication with the adapter writing tip.

Preferably the adapter is shaped so as to avoid obscuring the view of the imaging system when the adapter is attached to the digital pen. This may be achieved by the adapter writing tip being positioned so as to overlie the digital pen writing tip.

Preferably the adapter is shaped so as to receive the digital pen and attach to it. This may be achieved in one or more of several different ways. One option is for the adapter to provide an aperture for insertion of the digital pen, so that at least the writing tip of the digital pen protrudes from a forward end of the aperture. The aperture may be a closed (i.e. having a full circumference) or open (i.e. having only a partial circumference) aperture.

Preferably the aperture does not obscure the view of the imaging system. In this option, the fit between the digital pen and the adapter is preferably an interference fit..

Another option is for the adapter to include an arm or arms to embrace the digital pen, in a similar attached form to the aperture option set out above. In this option, the digital pen may be inserted into the adapter in a direction along the axis of the digital pen. Alternatively, the digital pen may be inserted in a direction transverse to the axis of the digital pen, so that the arms of the adapter are forced apart to allow entry of the digital pen, the pen then being held by the resilience of the arms.

Additionally, the adapter may include stabilising means provided axially longitudinally from the aperture or arms.

The stabilising means preferably provide further mutual attachment between the digital pen and the adapter. Most preferably, the stabilising means operate, with the aperture or arms, substantially to prevent relative movement between the digital pen writing tip and the adapter writing tip.

The stabilising means may attach to the digital pen at the writing tip end or at the non-writing tip end of the pen.

In the case where stabilising means are not provided, preferably the minimum extent of the attachment between the pen and the adapter is one-sixth or more of the longitudinal extent of the digital pen. Preferably this figure is one-fifth or more, or one quarter or more. It will be appreciated that the longer the longitudinal extent of the attachment between the adapter and the digital pen, then the more stable will be the relative positioning of the adapter pen writing tip and the digital pen writing tip.

Typical digital pens are activated to sense a writing event by detecting pressure on the digital pen writing tip, e.g. caused by writing with the digital pen on a writing surface.

It is preferred to harness this feature also using the adapter. Thus, preferably the adapter include pressure transmitting means to transmit pressure from the adapter writing tip to the digital pen writing tip, so that writing on a writing surface with the adapter writing tip causes sufficient pressure to be applied to the digital pen writing tip so that the digital pen senses a writing event.

The pressure transmitting means may be attached to the adapter writing tip at a first portion of the pressure transmitting means. A second portion of the pressure transmitting means may provide a bearing surface for bearing against the digital pen writing tip. Preferably, the pressure transmitting means is positioned so as to apply a substantially axially oriented pressure to the digital pen writing tip when a substantially axially oriented pressure is applied to the adapter writing tip.

The pressure transmitting means may be a lever attached at an attachment point to the adapter but preferably able to flex about the attachment point. The first portion of the pressure transmitting means may be located intermediate between the attachment point and the second portion of the pressure transmitting means.

It is possible for the ink reservoir to be provided in the form of a removable cartridge. In this case, the adapter writing tip may or may not form part of the same cartridge.

Preferably the adapter has an adapter housing that is attachable, e.g. as set out above, to the digital pen. The housing preferably provides a cartridge installation recess.

This recess may be in the form of an open or closed aperture, as discussed above with respect to the attachment between the adapter and the pen. When the recess is an open aperture, the cartridge may be inserted into the housing in a direction (at least in part) transverse to a principal axis of the cartridge. When the recess is a closed aperture, the cartridge may be inserted into the housing in a direction (at least in part) in line with the principal axis of the cartridge. -$

Alternatively, it is possible for the ink reservoir to be provided in the adapter itself, typically such that it is not user-replaceable. In this case, preferably adapter has a barrel portion, the ink reservoir being provided in said barrel. The ink reservoir may be at least partially visible to a user. This may be made possible by the provision of one or more windows in the adapter. This allows the user to determine the ink level in the reservoir. Where more than one window is provided, it may be preferred to provide an array of windows, so that the ink level may be determined by the presence or absence of ink at one or more of said windows.

Some digital pens have convexly curved outer profiles, so that the middle portion of the pen is thicker than the ends (as with traditional fountain pens, for example) . In that case, it is preferred that the corresponding surface of the adapter that abuts against the curved outer profile of the pen is concavely curved. Preferably this concave curvature is two-dimensional, since the pen also has convex curvature in the circumferential direction.

The digital pen writing tip itself may be provided by a first adapter, said first adapter being replaceable by a second adapter. In this case, the combination of digital pen and adapter may not have a separate writing tip apart from the adapter writing tip. In this case, the pen without any adapter is not capable of writing on the writing surface.

This arrangement may be preferred for dedicated digital marker pens. It is preferred to provide a single digital pen body with a plurality of adapters, since then each adapter may correspond to a different colour of ink, or simply each adapter may be disposable. In either case, preferably provision is made in the arrangement for a determination of the pressure on the writing tip, in order for there to be a determination of a writing event.

Typical known digital pens are provided with the digital pen writing tip as part of a replaceable cartridge, the cartridge including said digital pen writing tip at a forward end in communication with an ink reservoir located in a housing of the cartridge. Force-sensing means are typically provided in the digital pen for sensing pressure on the writing tip, transmitted via the housing of the cartridge. The writing tip of the replaceable cartridge is preferably operable to draw a line of a similar thickness to a conventional roller ball pen or similar. The cartridge is replaceable to allow the pen to continue operating when the ink runs out of the original cartridge.

Thus, in a preferred embodiment of the present invention, the digital pen may include such a replaceable cartridge.

In this embodiment, the replaceable cartridge is replaceable by an adapter that has an extension member for fitting into the pen in place of the replaceable cartridge. In this case, preferably the extension member provides a pressure-transmitting means between the adapter writing tip and the force sending means.

Preferably, the adapter dock provides an adapter station for each adapter. Each adapter station preferably provides releasable location means for positive location of at least part of an adapter. For example, the adapter may be received writing tip first into the adapter station. In that case, it is preferred that the adapter station provides a substantial seal to the writing tip, in order to reduce drying out of the adapter writing tip. This is particularly preferred when the adapter writing tip is a felt writing tip.

The seal may be provided by cooperation of the adapter with a corresponding rim surrounding the adapter station.

The adapter dock preferably provide three or more docking stations for a corresponding number of adapters. Each docking station may correspond to a particular colour, which in turn may correspond to a colour of the adapter writing tip intended to be stationed in the docking Station during non-use. Each docking station may be provided with a coding pattern corresponding to the colour of the adapter writing tip, the coding pattern being capable of being imaged by the imaging system of the digital pen. Most preferably, this coding pattern is provide adjacent or below a position at which the pen is located when the adapter is located in the station which the digital pen attached to the adapter. For example, the coding pattern may be located within a recess at the docking station.

The coding pattern may additionally or alternatively provide information relating to the size and/or shape of the adapter writing tip.

One preferred more of operation of the dock is as follows.

The adapters may be located in their corresponding stations.

Preferably the user attaches the digital pen to a desired adapter by placing the pen into the adapter in its station, clicking (or similar) the adapter into position by suitable manipulation of the pen, and then removing the attached combination of the pen and adapter. In this way, the pen may be able to image the coding pattern that signifies the relevant properties of the adapter pen, such as colour, writing tip size and/or shape.

Preferably, each station provides one rotational orientation for the adapter located in it. In this way, it can be ensured that the digital pen must attach to the adapter in the station in a correct orientation in order for the coding pattern to be correctly imaged.

The dock may further or alternatively provide a coding pattern located elsewhere on the dock than in a station recess, in order to provide the same or additional functional features to be detected by the pen.

Specific embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figs. 1A, lB and 1C show simplified schematic drawings of a digital pen and marker pen in different spatial combinations; Fig. 2 shows a digital pen and adapter according to an embodiment of the present invention; Fig. 3 shows a schematic sectional view of the embodiment of Fig. 2; Fig. 4 shows a digital pen and adapter according to another embodiment of the present invention; Fig. 5 shows a schematic sectional view of the embodiment of Fig. 4; Fig. 6 shows a digital pen and adapter according to another embodiment of the present invention; Fig. 7 shows a schematic sectional view of the embodiment of Fig. 6; Fig. 8 shows a digital pen and adapter according to another embodiment of the present invention; Fig. 9 shows a digital pen, adapters and dock according to an embodiment of the present invention; Fig. 10 shows the adapter of Fig. 9 in more detail; Fig. 11 shows an adapter dock according to an embodiment of the present invention, positioned at a fee-standing flip chart apparatus; p Fig. 12 shows a partial view of an adapter dock according to a modified embodiment of the present invention, positioned at a free-standing flip chart apparatus; Fig. 13 shows a partial view of an adapter dock according to a modified embodiment of the present invention, integrated with a free-standing flip chart apparatus.

The embodiments of the present invention are intended for use with known digital pens and their accessories. One suitable example is the Logitech (registered trade mark) io2 (trade mark) Digital Writing System. Furthermore, the embodiments of the present invention are intended for use with known position-coding writing surfaces, particularly Anoto (registered trade mark) patterned paper. A suitable position-coding pattern for use with the present invention is described in detail in WO 2006/049573, the content of which is incorporated herein by reference in its entirety.

Examples of suitable patterns are disclosed in US 6,570,104, US 6,663,008 and US 6,667,695, which are also incorporated herein by reference in their entirety.

The success of the digital pen comes about due to the possibility of a user carrying out writing or drawing operations on paper but being able to store that information electronically for future use and manipulation. The use of position-coding paper also allows for additional functionality based on specific position coding being associated with different parts of the writing surface. p

The embodiments of the present invention allow these advantages to be transferred from a single-user to a group-use collaboration tool. These embodiments allow the digital pen to be used on large format pads (e.g. flip-chart pads), allowing the text to be visible to all participants.

It is to be borne in mind here that the typical manner in which a user's hand holds a pen for writing on a desk or table is different compared with the same user writing on a more upright surface, such as a whiteboard or flipchart.

Typically, writing on a more upright surface, the pen tends to be closer to perpendicular to the surface than when writing on a horizontal surface.

Fig. 1A shows a schematic view of a digital pen 100 having a marker pen 102 attached. Figs. lB and 10 show similar devices, but in different spatial arrangements. In Fig. 1A, the writing surface 106 is imaged by aperture 110 of the digital pen. Marker pen tip 104 writes on the writing surface and digital pen writing tip 108 does not meet the writing surface.

The arrangement shown in Fig. lB has an advantage in that the user's grip is substantially in-line with the writing tip of the marker pen. However, the writing tip is obscured from the user's view and there may be an unbalanced feel to the user due to an awkward mass distribution. The arrangement of Fig. 1C suffers from the same problems.

The arrangement of Fig. 1A is therefore preferred. The user's grip is not in-line with the writing tip of the marker pen, but the user does have a good view of the writing tip of the marker pen during writing and having the mass of the whole device concentrated close to the user's grip gives a balanced feel.

The embodiment of the invention shown in Figs. 2 and 3 follows the above rationale. Digital pen 200 has a marker pen adapter 202 attached to it at the forward end of the barrel of pen 200. Adapter writing tip 204 is a felt writing tip that is held, as shown in Fig. 3, in the adapter by a pressure-transmitting means in the form of a cantilever 212 attached at one end at an internal wall of the adapter.

Cantilever 212 has a hole (not shown) for receiving a tang 214 of the writing tip 204. Tang 214 projects at its rearwards end into ink reservoir 216 at least partially filled with ink 218. The ink level 220 is visible to a user via light-transmitting window 222 Close to the free end of the cantilever 212, the writing tip 208 of the digital pen bears against the surface of the cantilever. Since the cantilever is able to flex about its attachment point to the internal wall of the adapter and holds the adapterwriting tip 204, then axial movement of the adapter writing tip due to the pressure applied by a user between the adapter writing tip and the writing surface (riot shown) is transmitted (and indeed slightly amplified) to the digital pen writing tip 208. Digital pen 200 includes known components for detecting writing pressure on the digital pen writing tip, in order to activate the imaging system of the pen. Thus, when the adapter is fitted and used to write on a writing surface, the pen is activated in a similar way to when the pen is itself writing on the writing surface.

The adapter fits to the digital pen by insertion of the digital pen into the closed aperture presented by the adapter. The aperture takes the form of a pipe having internal walls curved to match the corresponding outer profile of the barrel of the pen. An interference fit is achieved between the adapter and the pen at the position where the digital pen writing tip meets the bearing surface of the cantilever.

The aperture has an open end below the adapter writing tip, in order for the view of the imaging system of the digital pen not to be obscured. The aperture is "closed" in the sense that the outer circumferential profile of the adapter is continuous.

The adapter has an outer shape that conforms to the smooth curves of the digital pen, in order to make the combination of pen and adapter more comfortable for writing. It is intended that the user holds the outer surface of the adapter for writing on the writing surface. The ink reservoir 216 is refillable. In this embodiment, the ink is provided as a free liquid in the reservoir. However, it is possible for the ink to be provided an a captured form, for example in a gel or foam medium typical of felt tip pens.

In a modification of the embodiment shown in Figs. 2 and 3, the pressure-transmitting means may be other than a cantilever. In particular, the adapter writing tip may be spring-loaded so that the adapter writing tip is urged in a forwards direction by the spring loading of a writing tip mount element. Jhen writing, writing pressure between the writing surface arid the adapter writing tip acts against the urging of the spring loading, so that. Lhe adapter writing tip and hence the writing tip mount element move rearwardly.

The writing tip mount element includes a bearing surface bearing against the digital pen writing tip. Thus, rearwards movement of the writing tip mount element also causes rearwards movement of the digital pen writing tip, with the result that the digital pen senses a writing event.

Another modified embodiment is shown in Figs. 4 and 5.

Digital pen 300 has similar features and a similar shape to digital pen 200 of FigS. 2 and 3. In this embodiment, adapter 302 attaches to pen 300 by a combination of a closed aperture and a stabilising portion 303. The adapter has two parts -a cradle and a cartridge 305. Cartridge 305 is shown in both the unmounted and mounted positions in Fig. 4.

As shown in Fig. 5, the cradle provides at its forward end pressure transmitting means 312 for transmitting writing pressure from the adapter writing tip 304 to the digital pen writing tip 308. Cartridge 305 is inserted into the cradle by sliding location to snap fit with the adapter writing tip protruding through an aperture in pressure transmitting means 312 and the rear end of the adapter abutting against rear stop 309. The cradle provide laterally extending wings 311 for prevention of lateral relative movement between the cartridge and the adapter.

In the embodiment shown in Figs. 4 and 5, there may provided a single cradle and a plurality of cartridges, each cartridge corresponding to the same or a different colour.

In this way, the cartridge can be replaced either when the ink in a previous cartridge runs out or in order to change ink colour. Indicator 307 is provided in order to provide an indication of the ink colour for cartridge 305. Although not shown in Figs. 4 and 5, the cartridge may have a viewable ink reservoir similar to the embodiment of Figs. 1 and 2, or similar to that shown in later embodiments below.

A further modified embodiment is shown in Figs. 6 and 7.

Here, the adapter fits to digital pen 400 by the rear end of the digital pen being located in a closed, blind aperture at the rear end 421 of the adapter. Stabilising means are provided in the form of a flexible arm 423 and a forward attachment location provided between the forward ends of the adapter and pen. The adapter has a sleeve 425 into which cartridge 405 is inserted so that the adapter writing tip is presented from the forward end of the sleeve for writing.

Cartridge 405 has a colour indicator 407. As shown in Fig. 7, the sleeve may provide a slightly curved path for the cartridge, in order to conform to the outer profile of the pen. In this case, the cartridge may have a flexibility to allow the cartridge to assume this shape and yet still be removed without difficulty from the adapter. The pressure-transmitting means may be adopted as desired from either embodiment above.

Fig. 8 illustrates a different embodiment. In this case, a digital pen 500 is provided without a separate digital pen writing tip. Instead, the arrangement has a marker writing tip 504 provided only by adapter 502. Adapter 502 is removable from the pen 500 as shown in Fig. 8 and can be replaced using adapters 502a, 502b, 502c of the same shape but containing, for example, different colours of ink, or perhaps having different shaped writing tips. In this embodiment, there is provided a writing pressure determination means similar to that of a conventional digital pen, so that the pen can make a determination of whether or not a writing event is taking place, in order to activate the imaging system as appropriate. Adapter 502 may operate on a force sensing means of the digital pen in a similar way to the embodiment described above as a modified embodiment of Figs. 2 and 3 in which the adapter has an extension member that is located in place of a cartridge and writing tip of the digital pen.

Figs. 9 and 10 illustrate the embodiment that is at present most preferred. Digital pen 600 is shown held in adapter 602. Adapter 602 provides a closed aperture 621 at its rearward end for location of barrel 600a of the pen via an interference fit. The writing tip (not shown) of the pen is located at the forward end of the adapter in a similar manner to the embodiment of Figs. 2 and 3, to provide stabilising means. Arm 623 of the adapter is able to flex to allow the adapter to clip into position on the pen. An ink reservoir is provided in the adapter. Indicator windows 622 provide an indication of the ink level in the reservoir and also an indication of the ink colour.

The adapter is also provided with an attachment stud 630 at the closed aperture 621. Attachment stud may interact with the digital pen in order to activate the pen. This mimics a similar interaction between a digital pen and a digital pen cap that can be located at the rearward end of the pen in order to activate the pen.

The adapter may be provided with a removable cap 640 in order to prolong the time before the ink in the reservoir dries out.

Fig. 9 also illustrates a dock 650. In this illustration, the dock is capable of receiving four adapters: red, green, blue and black at stations 652. Each station 652 provideS a recess and a sealing rim, the sealing rim being capable of performing a similar function to cap 640.

Although not shown in Figs. 9 and 10, each station can be provided with a pen-readable coding pattern to signify to the pen that the adapter in that station has certain characteristics, e.g. colour and/or writing tip size and/or shape.

Fig. 11 illustrates a flip chart apparatus 50 according to an embodiment of the invention. A paper pad 52 (large format paper) is provided hooked onto a stand 51. Each sheet of paper is provided with a position-coding printed pattern as discussed above. Different parts of the paper may correspond to different functionalities, as is already known for paper of smaller formats. For example, the "subject" region 54 may include headings functionality different from the "body" region 56. The stand itself may be provided with one or more generic interface features such as project specific shortcuts to e-mail circulation lists or folder locations. The stand itself may further have pen specific features such as line weight or highlight. These may be provided at tray 58. In Fig. 11, tray 58 includes a dock having adapter stations 60, 62, 64, 66. The adapters 68 are similar to those shown in Figs. 2 and 3. Each station is provided with an adapter colour indicator to show where particular adapters should be located.

Fig. 12 illustrates a modified embodiment compared with Fig. 11 showing a flip chart apparatus 70 and showing the writing surface provided by flip chart paper 76. Fig. 12 shows showing in greater detail the generic interface features associated with the stand 71. Adapters 78 are located in their respective stations. A computer interface cable 73 for attachment to a conventional personal computer is shown.

This allows the use of an pen interrogation means 75 that is adapted to communicate with the digital pen 80 (typically via wireless communication, e.g. Bluetooth (registered trade mark)) . Such a device is similar in function to known pen docks, but of course has a different shape so that it is shaped to receive the combination of the digital pen and adapter.

Fig. 13 shows an alternative layout for the apparatus of Fig. 12. Standard Anoto features may provided at a lower part 90 of the flip chart, with generic features being provided as in Fig. 12 at a side portion 91 of the stand. The combination 92 of the pen and adapter is shown located in the pen interrogation means 95. Adapter stations 93 are located on another side portion of the stand for ease of access.

The above embodiments are described by way of examp1e.

Modifications of these embodiments, further embodiments and modifications thereof will be apparent to the skilled person on reading this specification and as such are within the scope of the present invention.

Claims

1. A digital pen adapter that is attachable to a digital pen having a digital pen writing tip, the adapter having an adapter writing tip exposable for contact with a writing surface in place of the digital pen writing tip.

2. A digital pen adapter according to claim 1 wherein the digital pen includes an imaging system adapted to image a portion of the writing surface located at or at a predetermined position from the tip of the digital pen writing tip when the digital pen writing tip is in contact with the writing surface.

3. A digital pen adapter according to claim 2 wherein the adapter is shaped so as to avoid obscuring the view of the imaging system when the adapter is attached to the digital pen.

4. A digital pen adapter according to claim 3 wherein the adapter writing tip is positioned so as to overlie the digital pen writing tip.

5. A digital pen adapter according to any one of claims 1 to 4 wherein the digital pen includes contact-detecting means for detecting contact between the digital pen and a writing surface.

6. A digital pen adapter according to any one of claims 1 to 5 wherein the adapter writing tip provides a line thickness on the writing surface that is at least two times the thickness of the line provided by the digital pen writing tip.

7. 1 digital pen adapter according to any one of claims 1 to 6 wherein the adapter writing tip is a felt writing tip.

8. A digital pen adapter according to any one of claims 1 to 7 including an ink reservoir in fluid communication with the adapter writing tip.

9. A digital pen adapter according to any one of claims 1 to 8 wherein the adapter is shaped so as to receive the digital pen and attach to it.

10. A digital pen adapter according to claim 9 wherein the adapter provides an aperture for insertion of the digital pen, so that at least the writing tip of the digital pen protrudes from a forward end of the aperture.

11. A digital pen adapter according to claim 10 including stabilising means provided axially longitudinally from the aperture to provide further mutual attachment between the digital pen and the adapter.

12. A digital pen adapter according to any one of claims 1 to 11 including pressure transmitting means to transmit pressure from the adapter writing tip to the digital pen writing tip, so that writing on a writing surface with the adapter writing tip causes sufficient pressure to be applied to the digital pen writing tip so that the digital pen senses a writing event.

13. A digital pen adapter according to claim 12 wherein the pressure transmitting means is attached to the adapter writing tip at a first portion of the pressure transmitting means and a second portion of the pressure transmitting means provides a bearing surface for bearing against the digital pen writing tip.

14. A digital pen adapter according to any one of claims 1 to 13 wherein an ink reservoir is provided in a removable cartridge for fitting to the adapter.

15. A digital pen adapter according to any one of claims 1 to 13 wherein an ink reservoir is provided in a barrel * portion of the adapter.

16. A digital pen adapter according claim 14 or claim 15 wherein the ink reservoir is at least partially visible to a user.

17. A digital pen adapter according to any one of claims 1 to 16 wherein the digital pen writing tip itself is provided by a first adapter, said first adapter being replaceable by a second adapter.

18. A kit of a digital pen and a digital pen adapter, the adapter being attachable to the digital pen, the digital pen having a digital pen writing tip, the adapter having an adapter writing tip exposable for contact with a writing surface in place of the digital pen writing point.

19. The kit of claim 18 including a position-coding writing surface.

20. A kit of a digital pen adapter according to any one of claims 1 to 17 and a position-coding writing surface.

21. A kit of two or more digital pen adapters according to any one of claims 1 to 17, each digital pen adapter corresponding to a different writing colour.

22. An adapter dock for receiving a plurality of digital pen adapters according to any one of claims 1 to 17.

23. An adapter dock according to claim 22 further including corresponding digital pen adapters and optionally also with one or more corresponding digital pens.

24. An adapter dock according to claim 22 or claim 23, the dock forming part of an apparatus providing a writing surface for the digital pen and/or the adapter.

25. An adapter dock according to any one of claims 22 to 24 wherein the adapter dock provides an adapter station for each adapter, each adapter station providing releasable location means for positive location of at least part of an adapter.

26. An adapter dock according to claim 25 wherein each docking station is provided with a coding pattern corresponding to the colour of the adapter writing tip, the coding pattern being capable of being imaged by the imaging system of the digital pen.

27. A method of operating a digital pen adapter, the adapter being according to any one of claims 1 to 17, the method including the steps of attaching the adapter to a digital pen and applying pen strokes to a writing surface using the adapter writing tip in place of the digital pen writing tip.