The present invention relates to push button assemblies, and particularly, but not exclusively, to illuminated push button assemblies for use in amusement or gaming machines. Conventional push button assembly as used with an amusement or gaming machine typically comprise a push button, a housing, a lamp and switch unit, and an actuating structure with a spring. GB 2350722 A discloses a push button assembly of this kind. The push button comprises a translucent disc, a transparency and a fitted lens cap. The housing is an open ended tubular structure with a flange around one end defining a bezel.

The push button is movably retained within the flange and the lamp and switch unit is removably attached to the opposite open end of the housing so that the lamp is within the housing for illumination of the button and the switch is outside the housing. In use the housing is passed through an aperture in a panel of the machine with the flange on the outside and a nut is screwed onto the tubular structure against the underside of the panel to hold the housing firmly attached to the panel.

Conventional push button assemblies for amusement or gaming machines are typically illuminated e.g. by an internal lamp, to attract attention to the button and to indicate the current functional status of the associated switch with regard to the game played with the machine. For example, where the assembly is a start button assembly the button may be illuminated with a steady or flashing light to indicate that the button can be pressed to initiate game play, the button otherwise being non-illuminated or differently illuminated. Illumination may be by means of an LCD or OLED light source or sources. Push buttons illuminated by OLED or LCD sources typically have small viewable areas when compared to the overall button size. The OLED or LCD screens are arranged inside the push button under the lenscap, and display the images only to the size of the viewable area of the LCD or OLED itself. This typically leaves a non-illuminated border area on the push button.

GB 2350722 provides a push button assembly where the button is surrounded by an external bezel that has an array of illuminable LEDs beneath it. Light is transmitted by light conducting elements to the bezel to provide a display of light spots which can twinkle or alternate to give an attractive changing pattern.

A disadvantage of the above described illumination means is that there is an area at the edges of the push buttons that cannot display an image. Additionally, a further disadvantage is that the illumination means is placed in a position where it typically provides the surface pressed by the user, or directly in contact with the top surface of the button and is separated from said button surface by a plastic film. As the illumination device is therefore constantly absorbing strikes by the user when in use, it is required to be particularly robust. Even so, the illumination device is therefore liable to failure which requires the time consuming and costly maintenance of the games machine by replacement of the illumination device. This replacement and maintenance may typically be achieved only by the replacement of the entire push button assembly.

There is a considerable need to solve the problems associated with prior illuminated push button assemblies as described herein. Embodiments of the present invention seek to provide illuminated push button assemblies, and in particular, but not exclusively, push button assemblies for use in gaming or amusement machines which provide more varied illumination arrangement for a push button assembly to facilitate a greater versatility of uses for the assembly. According to the present invention there is provided a push button assembly comprising a housing and a push button movably mounted to the housing wherein the push button comprises a rear projection surface.

Provision of a rear projection surface enables an image to be projected onto the push button. Thus, the appearance of the button can be easily changed by changing the projected image. The appearance obtained this way conveniently closely represents the appearance of a traditional push button in which a printed insert bearing an image is placed on a surface of the button and illuminated from behind. Also, provision of a rear projection surface enables any means for projecting light, and in particular an image, onto the surface to be spaced from the push button so that force applied to, and movement of, the push button is not transferred to the projection means during use of the button, reducing the risk of damage to the projection means.

The housing may have an open end bounded by a flange structure. The housing may be insertable through an aperture in a panel with the flange on an outer side thereof. The housing may be provided with a fixing means for fixing the housing relative to a panel. The push button may be mounted within the open end of the housing.

The push button may be at least partially transparent so that an image projected onto one side of the rear projection surface may be viewed from the opposite side of the surface.

The push button assembly may comprise a switch actuated by the push button.

The housing may comprise a pathway to allow an image to be projected onto the rear projection surface. This is in contrast to conventional push button assemblies where several components may be disposed directly behind the push button.

The rear projection surface may be provided by a rear projection film.

The push button assembly may further comprise a first illumination means arranged to project an image on to the rear projection surface, so that the image is displayed on the push button. The first illumination means may be positioned in spaced relationship from the rear projection surface. Where the push button assembly is provided with the flange the first illuminated means may also be arranged to illuminate the flange. The first illumination means may be mounted to the housing.

The push button assembly may be comprised in an amusement or gaming machine. In particular, the push button assembly may be mounted to a panel of the machine, In this case, the first illumination means may, where provided, be mounted to the push button assembly or otherwise mounted to the amusement or gaming machine. The amusement or gaming machine may be arranged to provide a game under control of an operating system wherein the operating system is operatively connected to the push button assembly and the first illumination means. The housing may comprise a hollow tubular body such as a cylindrical body open at opposite ends. The housing may have a generally open square frame structure comprising side wall structures with a flange structure mounted at one end. Alternatively the frame structure may be generally rectangular, circular, or polygonal in shape.

One of the side walls of the housing may be open, or openable, to provide access to the interior of the housing, The housing may provide electrostatic protection to any circuitry within said housing by providing "grounding members" which make contact with a panel in which the housing mounted. In this respect, a gaming machine housing on which the push button assembly is mounted may have low conductivity properties or there may be a printed "circuit" which leads across the panel to the housing which is grounded itself or which has an earthing/grounding component fixed thereto. This can prevent spurious and fraudulent actuation of the push button.

Grounding members may comprise, for example, carbon conductive structures or other suitable electrically conductive structures. In this respect, the flange may also be conductive and preferably comprises a carbon conductive material. The housing may have terminals which project downwardly for connection to the appropriate circuitry in a machine in which the illuminated push button assembly is installed.

The fixing means may comprise one or more clips provided on one or more side wall structures of the housing, and engageable with one or more holes provided in the panel. There may be pairs of spring clips on the outer sides of some or all opposing side wall structures of the housing. The or each clip may be engageable with the aperture for the housing, or a hole separate thereto. When fixed to an amusement or gaming machine, the push button assembly may be mounted on a panel of the machine. The panel may be a glass, plastics, metal, or other material or combination of materials. On insertion of the housing frame through the aperture in the panel the aforesaid spring clip or clips may spring outwards into position on the underside of the panel. This results in the flange and the push button being on the exterior of the panel, and the rest of the housing being below the panel,

The housing may have a flange part, and the flange may be arranged around all or part of the edge of the push button. The flange may be fixed to the housing by any suitable means, and may snap fit on the housing. The flange and the housing may be integral Preferably, the flange has outwardly inclined side walls which taper towards the top free end. The flange is preferably opaque or translucent.

The flange may be light-transmitting. The flange may provide an illuminable boundary, and may be illuminated by a second illumination means disposed therein. The second illumination means may comprise multiple LEDs on a printed circuit board, The second illumination means may be located within a peripheral part separate from the flange, such as beneath the flange, to produce boundary illumination through such part which is thereby appropriately light transmitting. In this case the flange need not be light transmitting, and may be opaque thereby to define a non-illuminable boundary between the button and the illuminable boundary. The flange and the aforesaid peripheral part may be of any suitable shape and thus may be generally ring shaped of circular conformation, or may be of square, triangular, or rectangular conformation. The flange and aforesaid peripheral part may therefore have the same or different from the cross-sectional shape of the aforesaid tubular body of the housing.

The second illumination means may comprise a plurality of independently operable LEDs, which may be operable together in a static or flashing arrangement to give the effect of a "halo" around the push button.

Alternatively the LEDs may be operable in any sequence to display points of light around the boundary of the flange.

The second illumination means may be arranged around the underside of the button to illuminate the flange around the push button. The second illumination means may be fixed directly to the housing, or to an independent moulding, or to an underside of the button mounting panel. This LED board could also mount a micro switch and or other devices for the assembly.

This provides an additional illumination arrangement where the boundary around the push button may be lit alone or with the first illumination means to indicate a different button status. Additionally or alternatively the illumination of the boundary may be operable in a non-play mode to attract players.

The second illumination means may be independently operable from said first illumination means. Alternatively, the second illumination means may operate dependently with the first illumination means. In this embodiment the second illumination means may be coordinated with the first illumination means to provide an enhanced visual effect which is more pleasing to the user. The second illumination means may comprise an electroluminescent film or wire. The electroluminescent film or wire may be enclosed within or embedded in the aforesaid peripheral part.

In an alternative embodiment the film or wire may be located in a groove provided around the periphery of the flange or the peripheral part. A single electroluminescent wire may be used to provide a continuous closed loop illumination path.

The second illumination means may emit white or coloured light when energised and may be arranged to emit a single coloured or multicoloured line of light to the boundary.

The push button assembly may have separate electrical connections or terminals for the first and second illumination means so that they may be controlled separately from one another. In use these separate connections and terminals may be connected

The push button may comprise a switch actuating structure, mounted upon which is a translucent cover part and a translucent cap or lenscap. The translucent cap may have an upwardly convex domed top wall with downwardly projecting edge walls. The cover part may have a projection on its lower surface for interaction with the spring members.

The cover part and the cap may be the same in shape as the frame structure of the housing. Alternatively, the cover part and the cap are the same in shape as the opening provided by the flange. The push button may comprise a cap which projects beyond an open top end of the housing and is movable within limits into and out of the housing.

An actuating structure may be movably mounted within the housing for transmitting movement of the push button to the switch for operating thereof. A spring means may be provided in the housing for spring loading the actuating structure. The switch may be mounted beneath an open bottom end of the housing and the actuating structure may have a foot which projects beyond the bottom end for operable engagement with the switch.

The switch may comprise a rectangular body with an upwardly projecting actuator and connector terminals. The body most preferably overlies the inner side wall structures within the confines of the housing with the terminals projecting out of the housing.

The switch may be a microswitch.

The switch actuating structure may have a generally square frame with a square bottom wall provided with a centrally disposed aperture. Two elongate legs with outwardly turned feet may be provided projecting from the centre of opposed bottom wall edges at right angles to the edges. The bottom wall may have spring members fixed across the frame to provide the relative movement of the button within the flange structure. Two of the opposed spring members may have push rods mounted in a downwardly projecting direction, which project through apertures in the bottom wall so as to be displaceable within the button. The switch may be mounted to an outside edge of the button housing. In this configuration the switch will not block light projected to the projection surface.

The switch may be a standard type micro switch typically used for push buttons for gaming machines. Alternative switches may selected from membrane switches, touch screen membranes mounted to the external surface of the push button, capacitive membranes mounted below the external surface of the push button, tactile force feedback devices (haptic device), optic switches, or hall effect switches.

Tactile feedback to the customer is an important factor for push buttons used in gaming machines, and the use of standard micro switches allows the user to obtain good feedback from the button upon actuation.

The rear projection surface of the push button may be arranged on a lower surface of the button. The rear projection surface may therefore form a portion or all of the push button surface which is internal in the gaming machine.

Alternatively, the rear projection surface may be arranged between internal and external surfaces of the push button in a sandwich type configuration.

At least some, and preferably substantially all, of the projection surface should be arranged such that it is able to allow light from the illumination means to fall upon it, and such that the surface may be visible to the gaming machine user during normal use of the gaming machine. The rear projecting surface may be formed by a projection film or projection coating. The rear projection surface may comprise a coating or film which is capable of receiving light from the first illumination means and causing the light to be displayed on the external surface of the push button. The film may be affixed to the push button by any suitable means. An example of a suitable affixing means would be glue. In an alternate embodiment the film may be self supporting.

The film or coating may be a transparent or semi transparent film or coating. Suitable films may be rear projection films. Such rear projection films are available commercially, and may be obtained from 3M of St Paul, United States of America under the trade mark Vikuiti. In embodiments of the present invention, the use of the film as the rear projection surface enables the projected image to fill most of the push button and give a better visual effect. It also allows the projected image to give the button the appearance of a traditional button with a printed insert under the push button surface which indicates a function of the button, It is also possible to have a section of the projected image that falls into a region on the panel of an amusement machine that is not a push button. The panel also has a region which is not a push button but is a fixed translucent panel with a rear projection film. This region is therefore also able to display light or an image projected from the first illumination means. The region may also comprise a rear projection surface. This region could be a panel used to display advertising, player tracking, denomination display, display credits, bonus features, game selection information, manufacturer's information, error messages or any other suitable images. The first illumination means may be mounted within the housing. In a preferred embodiment at least a major part of the first illumination means may be mounted outside the housing so that a major part of the illumination means is located outside the confines of the housing. In one embodiment, the first illumination means is mounted completely outside the confines of the housing. This embodiment allows for the housing and first illumination means to be two distinct integers which are not in direct contact.

The separation of the first illumination means and the housing allows for easier maintenance or replacement of either feature, The first illumination means may be arranged to enable projection of light on to a plurality of rear projection surfaces, at least one of which is comprised in a push button. This configuration would allow for a first illumination means to project light or images on to a multi push button assembly which comprised a number of illuminated push buttons. The first illumination means may also project light on to a further rear projection surface which was not comprised in a push button. Said further rear projection surface may have all the features described for the push button rear projection surface, but not be part of a push button assembly. The further rear projection surface may display images and message to the gaming machine user. The first illumination means may project light on to a rear projection surface, and said projected light may comprise projected images. The projected images may be images of simulated push buttons of a slot or gaming machine. Alternatively, said images may be of a plurality of messages that indicate the machine function of said wagering game, said images being displayed on said rear projection surfaces.

The first illumination means may project an image covering substantially all of the rear projection surface of the push button. The first illumination means therefore provides for an illuminated push button with a non-illuminated border as seen in conventional push buttons illuminated by OLED or LCD screens.

In a further embodiment, the first illumination means may project an image which is larger than the rear projection surface of the push button. In this embodiment, the projected image may illuminate a flange associated with the push button. The flange may therefore be illuminated by an image or animation which is projected from the first illumination means. Additionally, said further embodiment may be advantageous as a second illumination means to illuminate a translucent or transparent flange as described herein would not be required.

The first illumination means may be enclosed within a casing having an opening in at least one surface to allow projected light to pass through.

The first illumination means may comprise a controller unit capable of controlling the projected light. The controller unit may form part of the first illumination means itself, and may be contained within the casing which additionally comprises the projection device. In an alternative embodiment, the controller unit may be located outside the first illumination means case.

The controller unit may also control other illumination means which form part of the illuminated push button assembly, such as the second illumination means located in the flange. Additionally, the controller unit may control other illumination means located in a gaming machine.

The first illumination means displays an image which can be changed during gameplay, and which can display static or moving images or video. The first illumination means may project a static, animated or streaming video onto the back projection surface so the user sees a changeable display. This enables the gaming operator/manufacturer to configure the button panel or input device according to the game or specific needs of the customer.

The first illumination means may be selected from any suitable projecting video display device or projector.

Suitable first illumination means can be an LCD (liquid crystal display) or a DLP

(digital light projection) projection device. Other examples of suitable first illumination means include may be selected from liquid crystal on silicon (LCoS) technology, heads- up display (HUD), light pipe displays, fibre optic displays, laser projection displays and micro projectors.

The projected image can be projected directly onto the rear projection surface.

Alternatively the image could be directed via a single or multiple mirrors and/or light guides onto the rear projection surface. This embodiment would allow for different mounting locations of the first illumination means within the machine. One particularly suitable projection means for use as the first illumination means is a holographic laser projection. Projection using a holographic laser refers to the method of projection which comprises a diffraction pattern of the desired 2D image calculated using holographic algorithms, which is displayed on a phase-modulating Liquid Crystal on Silicon (LCOS) microdisplay. When illuminated by coherent laser light, the desired 2D image is projected.

An illuminated push button assembly may be supplied as a self-contained unit which may be fitted to any suitable machine such as a gaming machine. The assembly may be fitted to a new gaming machine, or may alternatively be retro-fitted to an existing gaming machine as a replacement for a conventional push button assembly.

It will be understood that the push button assembly of the present invention is not limited to use in any particular field, and it is envisaged that the assembly may be applied as desired. It is envisaged that the push button assembly may be particularly suited to use in the gaming industry, and in particular for use in gaming or amusement machines such as fruit machines.

When used with an amusement or gaming machine a push button assembly may be mounted on a panel of the machine by insertion of the aforementioned housing through an aperture in the panel so that the aforementioned flange and the push button are on the outer side of the panel. A suitable attachment means may be applied to the housing to fix this relative to the panel, e.g. a threaded nut engaged with a threaded portion of the housing.

For a better understanding of the invention, and to show how embodiments of the same may be carried into effect, reference will now be made, by way of example, to the accompanying diagrammatic drawings in which:

Figure 1 shows an exploded schematic perspective view of a push button assembly;

Figure 2 shows a schematic perspective view of an illuminated push button assembly comprising the push button assembly of Figure 1;

Figure 3 shows a schematic side view of the illuminated push button assembly of Figure 2;

Figure 4 shows a schematic perspective view of an illuminated multi push button assembly; and

Figures 5a, 5b, and 5c show schematic cut-away views of illuminated push button assemblies. Referring to Figure 1 , there is shown an exploded view of a push button assembly

(1) which is suitable for use as part of an illuminated push button assembly. The push button assembly (1) has a push button (2) with an actuating structure (Ia) movably mounted within a housing (6) for operation of a microswitch (12). The housing (6) provides a frame comprising side wall structures, with a translucent flange structure (7) mounted at a top open end thereof.

The axial length of the housing (6) is shorter than the horizontal length of the side wall structures, resulting in a short push button assembly (1).

The button (2) is formed from a partially or wholly transparent material, for example a plastics material, and has affixed upon it a rear projection film (8) to provide a rear projection surface. The film (8) is capable of receiving a projected image from a projector, and displaying the image so that it is visible from the top surface of the push button (2). The assembly (1) is installed in a panel (9) of a gaming machine such that the flange (7) is on the exterior surface of the panel (9), and a substantial part of the push button (2) is proud of the panel (9) and flange (7) so that only the flange (7) and the exterior surface of the push button (2) are visible above the panel to a user of the gaming machine.

The housing (6) has substantially no components located in the central portion (10) in order to allow an image projected from the rear to pass therethrough and be displayed on the rear projection film (8).

The housing (6) also comprises a bezel (13) having a number of LEDs (1 1) arranged thereupon. The bezel (13) is shaped such that it forms a peripheral part of the housing (6) thereby ensuring the central part (10) of the housing (6) is not obstructed.

The LEDs (11) are illuminated in different sequences as desired, and the light produced by the LEDs (11) is visible through the translucent flange (7).

Referring to Figure 2, there is shown a perspective schematic view of an illuminated push button assembly (20). The assembly (20) comprises a first illumination means which is a digital light projection device (21) arranged beneath a push button assembly of the type shown in figure 1, comprising a push button (22) surrounded by a flange (25).

The light projection device (21) has an opening (23) in a surface facing the push button (22) which allows the projected light to pass out of the device (21). The light projecting device (21) has a light source and control unit. As shown in Figure 2, the light source and control unit are contained within the device (21) casing. The use of a discrete fϊiliy contained projection device (21) as shown in Figure 2 allows for easier installation and removal for maintenance or replacement.

The push button (22) is shown fixed in a gaming machine panel (24). The top portion of the button (22) proud of the panel (24) and can be pressed by a gaming machine user. The lower surface of the push button (22) is the rear projection surface upon which the light from the projection device (21) is projected. The rear projection surface is formed by a film coating adhered to the rear of the push button (22).

The light is therefore projected on to the lower surface of the push button (22) and is visible through the upper surface of the button (22) to the game machine user. Referring to Figure 3 there is shown a side view of the illuminated push button assembly (20) of Figure 2. Figure 3 also shows the illumination means (21) which projects light on to the projection surface of the push button (22) which is on the push button (22) lower surface.

The illuminated push button assembly (20) of Figures 2 and 3 shows a single projection device (21) for each individual push button (22).

Referring to Figure 4, there is shown a schematic perspective view of a multi button assembly (40). Figure 4 shows a plurality of push buttons (41) installed in a single panel (45) associated with a single projection device (42). The image projected by the projector (42) is divided into different areas, each area representing the information to be displayed on one individual push button (41). Each push button may therefore show a different image. The back of the button assemblies (41) are cut away so as to allow the light from the single projector (42) to reach the rear projection surface of the button, but still allow for the mounting of a suitable switch mechanism. The machine software can control the output of the projection device (42), and therefore control the output to each button (42) independently from the others.

The buttons (41) are arranged on a panel (45) of a gaming machine. The panel (45) also comprises a region (44) which is not a push button (41) but which has a rear projection surface for receiving and displaying a projected image from the projector (42).

Referring to Figures 5a, 5b, and 5c, there are shown schematic side cut-away views of push button assemblies (50). The assemblies (50) each have a push button (51), with a rear projection film (53) able to display a projected image. The assemblies also each have a flange (52) which surrounds the periphery of the button (51). The assemblies

(50) are arranged and mounted in gaming machine panels (55) such that the push buttons

(51) and flanges (52) protrude from the panel (55) and are visible to the gaming machine user. Other components of each assembly (50) are arranged below the panel (55) in the interior of the gaming machine, and are therefore not visible to the user of the gaming machine.

The assembly (50) has a flange (52) part that can snap onto the top region around the push button (51). The assembly (50) also has a printed circuit board (56) around the underside of the push button (51), and the circuit board (56) is fixed to a moulding (58). The circuit board (56) has a number of LEDs attached upon it in order to illuminate the flange (52). A switch (54) is mounted to the outside edge of the button housing (57) so that it does not block the light from the projector. The switch (54) can be mounted on a printed circuit board (59) as shown in Figure 5c.

The switch (54) may also be directly mounted to the button housing (57) without the need for the moulding (58). The housing (57) would have to be installed from inside the machine connecting with the flange (52), and the housing would be screwed onto the underside of the panel (55).

A platform (60) protrudes from the push button (51) outwards in the direction of the switch (54), and operates the switch (54) when the push button (51) is pressed. A separate moulding or plunger (61) can also be introduced into the assembly (50) under the push button (51) lenscap as shown in Figure 5b. The separate moulding (61) acts to help the push button (51) move in a downward parallel motion when pressed, this plunger (61) then operates the micro switch or switches (54). This plunger (61) is made from non translusϊve material with better wear properties to ensure high life of the assembly (50). The switches (54) act upon the push button (51) to push it back into place after operation. In order to aid this action, the assembly (50) contains return springs (62).

It is to be understood that the invention is not to be limited to the details of the above embodiments, which are described by way of example only. Many variations are possible without departing from the scope of the appended claims.