EP1991921A2

EP1991921A2 - Healthcare keyboard

Info

Publication number: EP1991921A2
Application number: EP07712747A
Authority: EP
Inventors: Martin Baker; John Paisley; Tony Tamasauskas; Alan Bale; Paul Merritt; Timothy Waterman; Robert Platts
Original assignee: Devlin Electronics Ltd
Current assignee: Devlin Electronics Ltd
Priority date: 2006-02-20
Filing date: 2007-02-20
Publication date: 2008-11-19
Also published as: WO2007096593A2; WO2007096593A3; GB2435448A; GB2435448B; GB0603350D0

Abstract

A healthcare keyboard is provided with a key matrix (301) having contact zones (303a, 3O3...n), arranged to represent the layout of a keyboard, a processor (302) adapted to receive a signal from the key matrix (301) indicating whether a contact zone (303 a, 303...n), is open or closed and to transmit data to an external device, and a dedicated 'clean' key. The processor (302) is arranged to switch between a first mode of operation, in which the processor (302) is adapted to process data from the keys in the key matrix (301) and a second mode of operation in which the processor (302) is adapted to disregard signals from the keys in the key matrix (301) in response to receipt of an interrupt signal from the dedicated 'clean' key. Certain novel key shapes, profiles and cross sections are described, as well as internal arrangements and methods of use.

Description

Healthcare Keyboard

Field of the Invention

This invention relates to a keyboard such as for use in the field of healthcare and hygiene.

Background to the Invention

A typical modern computer keyboard such as that shown in Fig. 1 has between 80 and 110 keys which include: typing keys, a numeric keypad, function keys and control keys. Most operate using similar technology; switches and circuitry translate a person's keystrokes into a signal that a computer can interpret.

Inside a typical modern keyboard is a key matrix. The key matrix is a grid of circuits underneath the keys wherein each circuit is open at a location beneath a respective key. When a key is depressed it completes this circuit, allowing a small amount of current to flow which is picked up by a processor. When the processor detects a completed circuit, it compares the location of that circuit on the key matrix to a character map stored in a ROM to generate a signal that can be output to, and interpreted by, a computer. The character map tells the processor the position of each key in the matrix and what each keystroke or combination of keystrokes represents. The switch used to close the circuit on the key matrix may be non-moving and purely electrical (such as in capacitance switches) but more usually is electro-mechanical in nature. The mechanical part may be a rubber cap, metal contact, membrane or foam element, and all provide a different level of audible and tactile response.

Keyboards are subject to wear and tear, and the keys are required to operate through many thousands of depression-release cycles without failure. Keyboards are also subject to contamination from a wide range of substances, such as dust, dirt and spilled liquids, which can hinder the working of the keyboard if they are allowed to penetrate to the key matrix. Although metal contact and foam element based keyboards offer a good level of audible and tactile response they are particularly susceptible to this contamination. This problem is avoided in rubber cap and membrane based keyboards such as that described in GB 2,372,015 since the key matrix is protected from the external environment by an impervious rubber cap or elastomeric membrane.

Contamination from germs carried on the operator's fingers is a problem associated with all keyboards, and is particularly relevant in the field of keyboards used in the healthcare profession. Bacteria and viruses such as methicillin-resistant Staphylococcus aureus (MRSA) can be deposited from the fingers of one keyboard operator onto the keyboard and then later transferred to the fingers of a subsequent keyboard user, thus offering a potential cross-contamination route for the spread of diseases.

In an attempt to combat the problem of contamination, a silicone membrane can be provided, upon which the keys are moulded. The membrane encapsulates the circuitry of the keyboard thus offering an impervious outer layer which can be disinfected by wiping with a suitable cloth or by using UV sterilization.

The Applicant has noticed, however, that current sealed, cleanable keyboards have a major fault in that when such a keyboard is cleaned with a cloth, it is a common shortcoming for cloth to catch on the corners of the keys, thus dragging the material of the membrane in the direction of the cleaning cloth. This may give rise to a deterioration of the keyboard membrane and in severe cases can lead to the membrane becoming distorted such that the key no longer sits above its respective contact pad. If the cleaning force transmitted to the membrane by the snagged cleaning cloth is excessive, the membrane may even be torn, typically around the root of one of the keys, resulting in contamination ingress into the circuitry of the keyboard.

Furthermore, current cleanable keyboards have to be disconnected from their computer, or the computer itself turned off, before they can be cleaned. Pressure from the cleaning action acting on the membrane is interpreted as keystrokes by the processor, resulting in erroneous data being transmitted from the keyboard to the computer terminal.

US 5,500,655 (Isawa et al.) discloses a keyboard locking mechanism in which the keyboard may be locked against inadvertent input by use of a sliding mode selection switch. When this mode selection switch is located in the cleaning position, an internal switch between the keyboard and a control unit, through which inputs from the keyboard must pass, is opened. The keys of the keyboard are effectively physically disconnected from the control unit.

The Applicant has perceived the need of improving the keyboards which are generally used in the healthcare field, in order to make them easier to sterilize, so that the drawbacks mentioned above can be avoided or at least reduced.

Summary of the Invention

In accordance with a first aspect of the invention, a computer keyboard is provided comprising a key matrix having contact zones arranged to represent the layout of a keyboard, a processor adapted to receive a signal from the key matrix indicating whether a contact zone is open or closed and to transmit data to an external device, and a dedicated "clean" key. The processor is arranged to switch between a first mode of operation, in which the processor is adapted to process data from the keys in the key matrix and a second mode of operation in which the processor is adapted to disregard signals from the keys in the key matrix in response to receipt of an interrupt signal from the dedicated "clean" key.

A method of cleaning is also provided comprising: disabling a subset of the keys of the keyboard, cleaning the keyboard and then re-enabling the subset of keys of the keyboard once the cleaning operation is complete.

An advantage of this aspect of the invention is that erroneous input data will not be generated by the keyboard if a key is depressed during cleaning. This simplifies the cleaning operation, as the keyboard will not need to be unplugged from its computer, or the computer turned off, before it can be cleaned.

In accordance with a second aspect of the invention, a computer keyboard is provided comprising an elastomeric membrane having moulded thereon a series of depressible elastomeric protrusions. Each protrusion has contact means on its underside for contacting a contact zone on a circuit board when depressed. Each elastomeric protrusion comprises an upwardly projecting body with side walls being elastically deformable to return the protrusion to its original position when the protrusion is released. The sidewalls of the upwardly projecting body comprise a lower bevelled section and an upper inwardly sloping section, and in plan view each elastomeric protrusion has a fully rounded form.

In accordance with a third aspect of the invention, a computer keyboard is provided comprising: a printed circuit board; a front elastomeric membrane and a rear elastomeric membrane. The front elastomeric membrane is adapted to cover a first side of the printed circuit board and has moulded thereon a series of elastomeric protrusions, each protrusion having contact means on its underside for contacting a contact zone on the printed circuit board. The rear elastomeric membrane is adapted to cover a second side of the printed circuit board. The printed circuit board has at least one opening that passes through the body of the printed circuit board and at least one of the elastomeric membranes has at least one raised protrusion on its inner surface that is adapted to pass through the at least one opening and to be adhered to the inner surface of the other elastomeric membrane.

An advantage of the second and third aspects of the invention is that the healthcare keyboard will be less susceptible to rucking of the keyboard and tearing of the keyboard membrane, which will increase its durability and the useful life.

In accordance with a fourth aspect of the invention, a process for sterilising a keyboard is provided comprising autoclaving the keyboard.

The significant parts of one embodiment of a healthcare keyboard according to this invention will now be described, by way of example only, with reference to the drawings.

Brief Description of the Drawings

Fig. 1 is a diagram of a typical keyboard as known in the art.

Fig. 2 is an exploded isometric diagram of a preferred embodiment of the healthcare keyboard.

Fig. 3 is a schematic circuit diagram of a preferred embodiment of the healthcare keyboard showing its operating circuitry.

Fig. 4 is an isometric diagram of a portion of the preferred embodiment of the healthcare keyboard showing the keys in enlarged detail. Fig. 5 is a vertical cross-section through a key of a preferred embodiment of the healthcare keyboard.

Fig. 6 is a rear view of a preferred embodiment of the healthcare keyboard.

Description of the Embodiments

With reference to Fig. 2 the healthcare keyboard is composed of three principal components: a front elastomeric membrane 201, a printed circuit board (PCB) 202, and a rear elastomeric membrane 203.

The front elastomeric membrane 201, which in a preferred embodiment is made from silicone rubber, has moulded into its surface a number of raised protrusions representing keys. Protrusion 204 represents a typical key. These keys may be arranged in a standard Qwerty layout as depicted in Figure 1. The front elastomeric membrane 201 is adapted to be sealed in an impervious manner to the rear elastomeric membrane 203 around its periphery 205, thus forming a cavity between the front and rear elastomeric membranes 201, 203. In one embodiment this sealing is accomplished using a chemical adhesive but other methods, for example mechanical fixing may be used. The printed circuit board 202 is sandwiched between the two elastomeric membranes, sealed in the cavity formed between them.

Raised areas 206 on the inner surface 207 of the rear elastomeric membrane 203 pass through corresponding openings 208 formed in the printed circuit board 202. In a preferred embodiment, the openings 208 and the raised areas 206 are the same size and shape but the raised areas 206 may be smaller than the openings 208. They are adhered to the inner surface 209 of the front elastomeric membrane 201. Alternatively, the raised areas 206 are formed on the inner surface 209 of the front elastomeric membrane and pass through the openings 208 in the printed circuit board 202 to be adhered to the inner surface 207 of the rear elastomeric membrane 203. In a further embodiment, raised areas 206 are formed on the inner surfaces of both the front and rear elastomeric membranes and are adhered to the inner surfaces of their opposite membrane respectively. A chemical adhesive may be used to adhere the raised areas 206 to the inner surfaces of their respective opposite membranes but other methods like mechanical fixing may be used. The raised areas 206 and corresponding openings 208 are arranged such that they do not interfere with the normal operation of the keys. They are arranged in horizontal or vertical strips which are determined by the layout of the keyboard but anchor the front elastomeric membrane 201 to the PCB 202 and the rear elastomeric membrane 203.

Referring to Figs. 2 and 3, the printed circuit board 202, is sandwiched between the elastomeric membranes 201, 203 and comprises a key matrix 301 and a processor 302. The key matrix 301 consists of a plurality of contact zones 303a, 303b, 303... n, arranged so that a contact zone 303a, 303b, 303...n, lies beneath a respective key such that when the key is depressed it contacts the contact zone. Each contact zone 303a, 303b, 3O3...n, takes the form of an open zigzag arrangement of conductive material. Each contact zone in the key matrix 301 thus formed is connected to the processor 302, in a manner well known in the art, by two connections 304...n, 305...n giving it a unique position within the key matrix. A small voltage is applied to each contact zone 303a, 303... n, through a bus 306 (which in turn receives power from the USB or serial input cable 307). When a key is depressed, the underside of it contacts the contact zone and, having a conductive element, completes the broken circuit of the contact zone 303a, 3O3...n, allowing a small current to flow from the bus 306, though the circuitry of the key matrix 301, to the processor 302. The processor 302 uses a character map located in an onboard ROM 308 to transmit the correct signal, associated with the depressed key, to a computer (via the USB or serial cable) in a manner well known in the art.

In a preferred embodiment, a special "clean" key 210 is provided. In a preferred embodiment this "clean" key is a different shape to any other key on the keyboard. The respective contact zone 303a, 303...n, beneath this key is connected to the processor in the manner previously described. However, when the processor receives a signal from this key, i.e. the key is depressed, timer means 309 within the processor 302 begins a count. In a preferred embodiment the timer means 309 is a software timer although other embodiments will be obvious to one skilled in the art.

The timer means 309 continues to count for as long as the "clean" key 210 is depressed, and once a set duration has elapsed, the processor 302 latches from a first mode of operation into a second mode of operation whereby inputs received from all keys in the key matrix 301, excluding the signal from the "clean" key 210, are not processed. When the "clean" key 210 is depressed again, the timer means 309 again begins a count. Once a specific duration has elapsed, the processor 302 latches back to the first mode of operation whereby inputs received from all the keys in the key matrix 301 are processed. In a preferred embodiment the second mode of operation corresponds to the "Clean" key 210 being depressed so that the keyboard is deactivated for cleaning, and the first mode of operation corresponds to the "Clean" key 210 being depressed to activate the keyboard again once the cleaning operation has been carried out. In a preferred embodiment the duration required to disable the keyboard is approximately 3 seconds and the duration required to enable the keyboard is approximately 4 seconds.

In a preferred embodiment, visual indication of the fact that the processor is operating in the second mode, i.e. the keyboard is disabled for cleaning, is provided by a flashing L.E.D or row of flashing L.E.D.s (211, Fig. 1, Fig. 3) or other indicators on the surface of the keyboard. For this purpose, the processor 302 may cause indicators dedicated to other functions in the first mode (normal operation) such as a caps lock L.E.D, a numeral lock L.E.D, a power L.E.D and the like to enter a flashing mode when the processor 302 is in the second mode. Alternatively, two L.E.Ds are provided on the surface of the keyboard, each corresponding to an operating mode of the processor, such that one or the other will light depending on which mode the processor is operating in and hence indicate whether the keyboard is disabled for cleaning or not.

Referring now to Figure 4, a key (as represented by typical key 204) may be moulded in a number of different shapes as represented by 401, 402, 403 and 404. The corners of each of protrusions 401, 402, 403 and 404 are fully rounded. Each corner has a minimum curvature (maximum radius) that is possible given the size of the key.

Various keys are composed of a combination of square and rectangular forms such that each convex or concave corner of each square or rectangular form comprises a circular sector 405. For each convex corner, the sector radius 406 is equal to half the width of that part of the key. Some keys (e.g. key 403) have a wider end and a narrower end. The edge of the key follows a curve between these parts of a radius equal to or greater than the radius of the corner sectors of the key. The concave curved parts merge with the convex curved parts. Between the convex and concave portions of the key edge there is little or no straight portion.

With these arrangements, cleaning of the keyboard is made easier and more thorough. In contrast to the keys of the keyboard of Fig. 1, the corners of the keys are easy to clean around. Straight edges between keys are minimised, thereby minimising dead spaces that require cleaning in a particular direction. Referring to Figure 4 and 5, a single key 204 is located above a single contact zone 303 and comprises a solid body section 501 having a concentrically located, protruding contact means 502 beneath the solid body section 501. In a preferred embodiment this contact means 502 has a conductive element on its underside. Alternatively, the contact means 502 itself may be constructed from conductive material. The solid body section

501 has an inwardly sloping circumference 503 and, optionally, a dish shaped recess 504 at the top. It is connected to and supported away from the upper surface 505 of the front elastomeric membrane 201 by an annular web 506 attached around its lower circumference.

In a preferred embodiment the angle of the web 506 to the vertical is 45 degrees but may be between about 10 and about 70 degrees. The angle of the inwardly sloping circumference 503 to the vertical is about 10 degrees but may be between about 5 and about 50 degrees. The solid body section 501 may be domed, such that the inwardly sloping circumference 503 begins to slope at an angle to the vertical in the above range, but with an increasing angle progressing upwardly.

The lower surface of the contact means 502 is separated from the surface of the contact zone 303 by a gap between the two when the key 204 is in its relaxed state.

In the preferred embodiment, the thickness of the front elastomeric membrane 201 is about 2.5 mm, the thickness of the supporting web 506, is about 0.5 mm and the separation between contact means 502 and contact zone 303, is about 1.5 mm.

When the key 204 is depressed, web 506 deforms to allow vertical movement of the solid body 501 such that contact means 502, suspended below the solid body 501, is forced into surface contact with contact zone 303. Once the key 204 is released, the web 506 is able to elastically recover to its original position thus raising the solid body 501. The supporting web 506 collapses and returns in a toggling manner, giving a positive feel to the user.

Key 204 is typically circular with a single centrally located contact means 502, but other shapes of key 401, 402, 403, may have different arrangements of contact means as shown in Figure 6.

A particular advantage of the embodiment of the invention depicted in Figs. 1 to 6 is that the rounded shape of the protrusions prevents snagging of cleaning materials on their edges, thus reducing the likelihood of damage occurring to the elastomeric material through tearing and stretching. A further advantage is that the raised areas of the rear elastomeric membrane 206, bonded to the front elastomeric membrane 201 through openings 208 in PCB 202, prevent rucking and translational movement of the front elastomeric membrane 201 during use.

The use of the clean key 210 to disable the key matrix 301 has the advantage that the keyboard can be cleaned whilst still attached (by wire or wirelessly) to an operating computer without transmitting erroneous and nonsense data to the computer.

As a result of the keyboard electronics being sealed within the cavity formed by the impervious front 201 and rear 203 elastomeric membranes, the keyboard may be safely sterilised in an auto-clave. It is preferably heated with a quantity of water to boiling point at a pressure of about 103 kPa for at least 15 minutes. This allows steam in the autoclave to reach about 121 ⁰C. It is found that the keyboard and its electronic circuitry suffer no ill effects during this process. This process offers the advantage of a practical sterilisation method within hospitals and the like.

Claims

CLAIMS:

1. A computer keyboard comprising: a key matrix (301) comprising contact zones (303a, 303b, 303...n) arranged to represent the layout of a keyboard; a processor (302) adapted to receive a signal from the key matrix (301) indicating whether a contact zone (303a, 303b, 303...n) is open or closed and to transmit data to an external device, characterised by: a dedicated "clean" key, the processor (302) being arranged to switch between a first mode of operation, in which the processor is adapted to process data from the keys in the key matrix and a second mode of operation in which the processor is adapted to disregard signals from the keys in the key matrix, in response to receipt of an interrupt signal from the dedicated "clean" key

2. A keyboard in accordance with claim 1, further comprising timer means (308) arranged to receive the interrupt signal from the dedicated "clean" key and to measure the duration of the interrupt signal.

3. A keyboard in accordance with claim 2, wherein the timer means (308) is a software timer.

4. A keyboard in accordance with any one of claims 1 to 3, wherein, in the second mode, the processor does not disregard signals from the

"clean" key.

5. A keyboard in accordance with any one of claims 1 to 4, wherein the processor is arranged to operate in the second mode of operation upon the timer means (308) recording the receiving of the interrupt signal from the dedicated "clean" key for a first set duration.

6. A keyboard in accordance with any one of claims 1 to 5, wherein the processor is arranged to operate in the first mode of operation upon the timer means (308) recording the receiving of the interrupt signal from the dedicated "clean" key for a second set duration.

7. A keyboard in accordance with any one of claims 1 to 5, wherein the interrupt signal adapted to cause the processor to operate in the first mode of operation is provided by a dedicated key that is not the dedicated "clean" key.

8. A keyboard in accordance with any preceding claim, wherein the first duration is approximately 2 to 4 seconds.

9. A keyboard in accordance with any preceding claim wherein the second duration is approximately 3 to 6 seconds.

10. A keyboard in accordance with claims 8 and 9, wherein the first and second durations are equal.

11. A keyboard in accordance with any one of the preceding claims, further comprising a front elastomeric membrane (201) adapted to cover the key matrix (301), having moulded thereon a series of elastomeric protrusions (204), each protrusion (204) having contact ^• means (502) on its underside for contacting a contact zone (303) on the printed circuit board (202).

12. A keyboard in accordance with any one of the preceding claims, wherein the dedicated "clean" key has a word, words or symbols affixed thereon or fixedly associated therewith conveying the meaning that the key is provided for a cleaning mode of operation.

13. A keyboard in accordance with any preceding claim, further comprising visual indication of the mode of operation of the processor.

14. A keyboard in accordance with claim 13, wherein the visual indication comprises a flashing indicator arranged to flash when the processor is operating in the second mode of operation.

15. A keyboard in accordance with claim 13, wherein the visual indication comprises two L.E.Ds arranged such that one L.E.D will light when the processor is operating in the first mode of operation and the other will light when the ^■ processor is operating in the second mode of operation.

16. A keyboard in accordance with claim 15, wherein the two L.E.Ds are differently coloured.

17. A method of cleaning a keyboard having keys, comprising the steps of: disabling a subset of the keys of the keyboard; cleaning the keyboard; re-enabling the subset of the keys of the keyboard once the cleaning operation is complete.

18. A method in accordance with claim 17, wherein the method step of disabling the keys of the keyboard comprises depressing a dedicated "clean" key.

19. A method in accordance with claim 17, wherein the method step of re- enabling the keys of the keyboard comprises depressing the dedicated

"clean" key.

20. A method in accordance with claim 17, wherein the method step of re- enabling the keys of the keyboard comprises depressing a dedicated key other than the dedicated "clean" key.

21. A method in accordance with claim 17 or 18, wherein the dedicated "clean" key is depressed for a duration of approximately 2 to 4 seconds.

22. A method in accordance with claim 17 or 19, wherein the dedicated "clean" key is depressed for a duration of approximately 3 to 6 seconds.

23. A computer keyboard comprising: a printed circuit board (202); a front elastomeric membrane (201) adapted to cover a first side of said printed circuit board (202), having moulded thereon a series of elastomeric protrusions (204), each protrusion (204) having contact means (502) on its underside for contacting a contact zone (303) on the printed circuit board (202); a rear (203) elastomeric membrane adapted to cover a second side of said printed circuit board (202); characterised in that: the printed circuit board (202) has at least one opening (208) that passes through the body of the printed circuit board (202) and at least one of the elastomeric membranes (201, 203) has at least one raised protrusion (206) on its inner surface that is adapted to pass through at least one opening (208) and to be adhered to the inner surface of the other elastomeric membrane.

24. A keyboard in accordance with claim 23 wherein the front and rear elastomeric membranes (201, 203) are silicone membranes.

25. A keyboard in accordance with claim 23, wherein there is a plurality of openings (208) and raised protrusions (206).

26. A keyboard in accordance with any one of claims 23 to 25, wherein the openings (208) and raised protrusions (206) are substantially rectangular.

27. A keyboard in accordance with claims 23 to 26, wherein the openings (208) comprise discrete holes in the printed circuit board (202).

28. A keyboard in accordance with claims 23 to 27 wherein the raised areas (206) are substantially the same size and shape as the openings (208).

29. A keyboard in accordance with any one of claims 23 to 28, wherein the openings (208) and raised areas (206) are dispersed across areas of the printed circuit board that correspond to areas of the keyboard that are substantially free of keys.

30. A keyboard in accordance with any one of claims 23 to 29, wherein the openings (208) and raised areas (206) are distributed across substantially the entire horizontal and vertical width of the keyboard.

31. A keyboard in accordance with any one of claims 23 to 30, wherein the openings (208) and raised areas (206) extend substantially to the edge of the PCB (202) and elastomeric membranes (201, 203) respectively.