Abstract:
An open-ended bonus gaming machine and method are disclosed. A gaming machine includes a game with a bonus game initiated upon a triggering event and a register that is modified by one or more units based on predefined criteria. The bonus game terminates when the register contains a predefined value.

Description:
RELATED APPLICATIONS  
       [0001]     This application claims priority from provisional application 60/715,763 filed on Sep. 10, 2005, hereby incorporated by reference. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention is directed to gaming machines and methods and, more particularly, to gaming machines and methods that provide an open-ended bonus.  
       BACKGROUND OF THE INVENTION  
       [0003]     In the prior art, various types of gaming machines have been developed with different features to captivate and maintain player interest. For example, gaming machines may include flashing displays, lighted displays, or sound effects to capture a player&#39;s interest in a gaming device. In general, a gaming machine allows a player to play a game in exchange for a wager. Depending on the outcome of the game, the player may be entitled to an award which is paid to the player by the gaming machine, normally in the form of currency or game credits.  
         [0004]     Another important feature of maintaining player interest in a gaming machine includes providing the player with many opportunities to win awards, such as cash or prizes. For example, in some slot machines, the display windows show more than one adjacent symbol on each reel, thereby allowing for multiple-line betting. Other types of slot machines have been developed that offer second-chance or bonus games that provide players with additional opportunities to win, such as with additional free spins. Some gaming machines offer a player the opportunity to win millions of dollars by providing progressive jackpots; while some gaming machines include bonus games that are used to entice and enhance player excitement. For instance, bonus features of various types have been employed to reward players above the amounts normally awarded on a standard game pay schedule. Generally, such bonus features are triggered by predetermined events such as one or more appearances of certain combinations of indicia in the “base game”. In order to stimulate interest, bonus awards are typically set to occur at a gaming machine on a statistical cycle based upon the number of base game plays.  
         [0005]     While gaming machines including bonus games have been very successful, there remains a need for gaming machines that provide a player with enhanced excitement and increased opportunity of winning.  
       SUMMARY OF THE INVENTION  
       [0006]     In accordance with one aspect of the present invention, a gaming machine includes a central processing unit operatively coupled to a set of player-operated controls, a memory configured to store a wagering game program operable by the central processing unit in accordance with the player-operated controls, and a display device controlled by the central processing unit upon a triggering event to display a bonus game. The bonus game includes a register that is modified by one or more units based on predefined criteria. The display of the bonus game terminates when the register contains a predefined value.  
         [0007]     In accordance with another embodiment of the invention, a method of operating a game includes the steps of accepting a wager from a player; initiating play of a game; and selecting one of a set of possible outcomes of the game, the set of possible outcomes including a winning subset of outcomes. The method further includes the steps of, upon a triggering event, initiating a bonus game; modifying a register by one or more units based on predefined criteria, and terminating the bonus game when the register contains a predefined value.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]     The accompanying drawings incorporated in and forming a part of the specification, illustrate several aspects of the present invention, and together with the description serve to explain the principles of the invention. In the drawings:  
         [0009]      FIG. 1  is a perspective view of a gaming machine in accordance with one aspect of the present invention.  
         [0010]      FIG. 2  is a block diagram of the physical and logical components of the gaming machine of  FIG. 1 .  
         [0011]      FIG. 3  is a display image associated with a game of one embodiment of the invention.  
         [0012]      FIG. 4  is a display image of a multi-page pay table for a game in accordance with one aspect of the invention.  
         [0013]      FIGS. 5-9  are display images of a game awarding bonus games in accordance with one embodiment of the invention.  
         [0014]      FIG. 10  is a functional block diagram depicting the steps associated with carrying out a method in accordance of one aspect of the invention.  
         [0015]      FIG. 11  is a schematic block diagram showing the hardware elements of a networked gaming system in accordance with one aspect of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0016]     In accordance with one aspect of the present invention,  FIG. 1  illustrates a gaming machine  100  including cabinet housing  120 , base game display  140 , player-activated buttons  160 , player tracking panel  136 , bill/voucher acceptor  180  and one or more speakers  190 . Cabinet housing  120  is a self-standing unit that is generally rectangular in shape and may be manufactured with reinforced steel or other rigid materials which are resistant to tampering and vandalism. Cabinet housing  120  houses a processor, circuitry, and software (not shown) for receiving signals from the player-activated buttons  160 , operating the games, and transmitting signals to the respective displays and speakers. Any shaped cabinet may be implemented with any embodiment of gaming machine  100  so long as it provides access to a player for playing a game. For example, cabinet  120  may comprise a slant-top, bar-top, or table-top style cabinet. The operation of gaming machine  100  is described more fully below.  
         [0017]     The plurality of player-activated buttons  160  may be used for various functions such as, but not limited to, selecting a wager denomination, selecting a game to be played, selecting a wager amount per game, initiating a game, or cashing out money from gaming machine  100 . Buttons  160  function as input mechanisms and may include mechanical buttons, electromechanical buttons or touch screen buttons. Optionally, a handle (not shown) may be rotated by a player to initiate a game.  
         [0018]     In other embodiments, buttons  160  may be replaced with various other input mechanisms known in the art such as, but not limited to, a touch screen system, touch pad, track ball, mouse, switches, toggle switches, or other input means used to accept player input. For example, one input means is a universal button module as disclosed in U.S. application Ser. No. 11/106,212, entitled “Universal Button Module,” filed on Apr. 14, 2005, which is hereby incorporated by reference. Generally, the universal button module provides a dynamic button system adaptable for use with various games and capable of adjusting to gaming systems having frequent game changes. More particularly, the universal button module may be used in connection with playing a game on a gaming machine and may be used for such functions as selecting the number of pay lines to play in a game and the number of credits to bet per line.  
         [0019]     Cabinet housing  120  may optionally include top box  150  which contains “top glass”  152  comprising advertising or payout information related to the game or games available on gaming machine  100 . Player tracking panel  136  includes player tracking card reader  134  and player tracking display  132 . Voucher printer  130  may be integrated into player tracking panel  136  or installed elsewhere in cabinet housing  120  or top box  150 .  
         [0020]     Game display  140  presents a game of chance wherein a player receives one or more outcomes from a set of potential outcomes. For example, one game of chance is a video slot machine game, an example of which is entitled Rock Hound. The Rock Hound game features a basic slot machine game with five simulated spinning reels and is further described below. In other aspects of the invention, gaming machine  100  may present a mechanical reel slot machine, a video poker game, a video keno game, a lottery game, a bingo game, a Class II bingo game, a roulette game, a craps game, a blackjack game, a mechanical or video representation of a wheel game or the like. In alternative embodiments, it may further be appreciated that games of skill or games of chance involving some player skill may be implemented with gaming machine  100 .  
         [0021]     Mechanical or video/mechanical embodiments may include game displays such as mechanical reels, wheels, or dice as required to present the game to the player. In video/mechanical or pure video embodiments, game display  140  is, typically, a CRT or a flat-panel display in the form of, but not limited to, liquid crystal, plasma, electroluminescent, vacuum fluorescent, field emission, or any other type of panel display known or developed in the art. Game display  140  may be mounted in either a “portrait” or “landscape” orientation and be of standard or “widescreen” dimensions (i.e., a ratio of one dimension to another of at least 16×9). For example, a widescreen display may be 32 inches wide by 18 inches tall. A widescreen display in a “portrait” orientation may be 32 inches tall by 18 inches wide. Additionally, game display  140  preferably includes a touch screen or touch glass system (not shown) and presents player interfaces such as, but not limited to, credit meter  144 , win meter  142  and touch screen buttons  146 . An example of a touch glass system is disclosed in U.S. Pat. No. 6,942,571, entitled “Gaming Device with Direction and Speed Control of Mechanical Reels Using Touch Screen,” which is hereby incorporated by reference.  
         [0022]     Game display  140  may also present information such as, but not limited to, player information, advertisements and casino promotions, graphic displays, news and sports updates, or even offer an alternate game. This information may be generated through a host computer networked with gaming machine  100  on its own initiative or it may be obtained by request of the player using either one or more of the plurality of player-activated buttons  160 ; the game display itself, if game display  140  comprises a touch screen or similar technology; buttons mounted about game display  140  (not shown) which may permit selections such as those found on an ATM machine, where legends on the screen are associated with respective selecting buttons; or any player input device that offers the required functionality.  
         [0023]     Cabinet housing  120  incorporates a single game display  140 . However, in alternate embodiments, cabinet housing  120  or top box  150  may house one or more additional displays or components (not shown) used for various purposes including additional game play screens, animated “top glass,” progressive meters or mechanical or electromechanical devices such as, but not limited to, wheels, pointers or reels. The additional displays may or may not include a touch screen or touch glass system.  
         [0024]     In accordance with one embodiment of the present invention,  FIG. 2  is a block diagram showing the interconnection of physical and logical components  200  of gaming machine  100 . Currency acceptor  210  is typically connected to central processing unit (“CPU”)  205  by a serial connection such as RS-232 or USB. CPU  205  executes game program  220  that causes video display screen  230  to display a game that includes a plurality of simulated indicia-bearing reels  270 . In one embodiment, game program  220  is a game such as Rock Hound, described further below.  
         [0025]     When a player has inserted a form of currency such as, for example and without limitation, paper currency, coins or tokens, cashless tickets or vouchers, electronic funds transfers or the like into currency acceptor  210 , a signal is sent to CPU  205  which, in turn, assigns an appropriate number of credits for play. The player may further control the operation of gaming machine  100 , for example, to select the number of pay lines to play and the amount to wager via electromechanical or touchscreen buttons  250 . The game starts in response to the player pulling a lever or pushing one of buttons  250 , the detection of which causes CPU  205  to spin reels  270  displayed on video display screen  230 . Random number generator  240  responds to instructions from CPU  205  to provide a randomly selected stop position for each reel. CPU  205  then stops the reels according to the predetermined stop positions to display a plurality of reel indicia on video display screen  230 . The set of possible outcomes includes a subset of outcomes related to the triggering of play of free games. In the event the displayed outcome is a member of this subset, CPU  205  under control of game program  220 , causes reels  270  to spin one or more additional times as will be described further below.  
         [0026]     In various embodiments of gaming machine  100 , game program  220  is stored in a memory device (not shown). By way of example, but not by limitation, such memory devices include external memory devices, hard drives, CD-ROMs, DVDs, and flash memory cards. In an alternative embodiment, the game programs are stored in a remote storage device. In one embodiment, the remote storage device is housed in a remote server. The gaming machine may access the remote storage device via a network connection, including but not limited to, a local area network connection, a TCP/IP connection, a wireless connection, or any other means for operatively networking components together. Optionally, other data including graphics, sound files and other media data for use with gaming machine  100  are stored in the same or a separate memory device (not shown).  
         [0027]     Predetermined payout amounts for certain combinations of reel indicia, including bonus game outcomes, are stored as part of game program  220 . Such payout amounts are, in response to instructions from CPU  205 , provided to the player in the form of coins, credits or currency via payout mechanism  260 , which may be one or more of a credit meter, a coin hopper, a voucher printer, an electronic funds transfer protocol or any other payout means known or developed in the art.  
         [0028]     Turning now to  FIG. 3 , in accordance with one embodiment of the invention, the Rock Hound game is implemented on video display  300  using five simulated spinning reels  301 - 305 . Each of 15 pay line patterns  312  (shown superimposed on the normal game screen) passes through one indicium on each of the five reels  301 - 305 . The number of pay lines and their patterns are by way of example only and may vary. The player selects the number of played pay lines and the number of credits or coins wagered on each line using touch screen controls (not shown) or buttons  160  ( FIG. 1 ). The player may also collect the balance of his credits by pressing CASH OUT button  340 .  
         [0029]     Credit meter  315  display the player&#39;s current credit balance, while other meters  316  may display, for example, the number of credits or coins wagered and the last amount paid by the payout mechanism  260  ( FIG. 2 ). Other meters  316  containing other information may be displayed. The amount wagered on each pay line is additionally indicated by a bet tag  310  corresponding to each pay line. In the example shown, 20 credits have been wagered on each of the 15 pay lines.  
         [0030]     The player initiates game play by pressing SPIN button  330 . In some embodiments, the player may simultaneously select all pay lines at the maximum number of coins or credits allowed per line by pressing a MAX BET touch screen button (not shown). Corresponding buttons  160  ( FIG. 1 ) may be used instead of the touch screen buttons to perform the actions described here without deviating from the scope of the invention. A video representation of reels  301 - 305  is made to spin and stop in their predetermined stop positions and then indicate whether the stop positions of the reels resulted in a winning game outcome.  
         [0031]     Winning outcomes may be indicated on a pay table. An example of part of a pay table  400  is shown in  FIG. 4 . The pay table may be accessible through a SEE PAYS “help” button  325 . In alternate embodiments, the pay table may be presented on a second video or printed display attached to the gaming machine (i.e. a “pay glass”,  FIG. 1, 152 ). A winning combination, for example, could be three or more green gem symbols adjacent to one another on an active pay line. For each winning combination, the game device awards the player the award in the pay table, adjusted as necessary based on the number of credits wagered on the pay line on which the win occurred. Some representations of pay tables may factor in the amount of the player&#39;s wager and no additional award adjustment is required.  
         [0032]     In various embodiments, winning combinations may be evaluated across adjacent reels from left-to-right, from right-to-left or both. Additional winning combinations may be awarded when certain indicia do not necessarily accumulate adjacently on a pay line, but rather, appear anywhere on the reels (i.e., “scatter pays”). In addition, “wild” indicia may be used to complete winning combinations. Some “wild” indicia may also cause completed winning combinations to be result in pay amounts in excess of the normal winning combination by way of multiplication or addition, for example, a wild doubler symbol may be used.  
         [0033]     Once the player triggers the free game feature, a pre-determined minimum number of free games is assigned to a counter and presented to the player. A different embodiment may allow the player to choose the minimum number of free games he desires. Another embodiment may choose from a pool of pre-determined minimum number of free games to begin the bonus round. In another embodiment, the minimum number of free games is a fixed value. In the Rock Hound game, the minimum number of free games the player receives is determined by the following equation: ((total number of symbols on reel)/(number of decrementing symbols*3))*(minimum games awarded)=expected number of spins for the player.  
         [0034]     For example, if there are 30 symbols on the fifth reel, eight decrementing symbols on reel five and five free games awarded at the minimum, the average number of free games for the player would be 6.5: (30/(8*3))*5=6.5.  
         [0035]     It will be apparent that various base game outcomes can be utilized to trigger the play of free bonus games, including, but not limited to, awarding bonus play when certain symbols appear on a pay line, when certain symbols are scattered, when no symbols of a certain type appear, when a certain winning combination occurs or, regardless of the visible symbols, at random or fixed intervals. In other embodiments, free games that do not use reels may be awarded. For example and without limitation, free games that present cards, roll dice, spin wheels, or offer a “second screen” bonus may be awarded either on the primary game display or on a separate display or device, for example on a video display or mechanical wheel. Multipliers may or may not be applied to pays during free games. Free games may include scatter pays or be implemented on reels which are separate from the base game.  
         [0036]     The player may press a “start” button at the beginning of each free game, or the games may proceed automatically. In the Rock Hound embodiment, the reels are spun automatically and stopped, then evaluated for any winning combinations. If winning combinations are present, the combinations are evaluated against a pay table and awarded to the player on a bonus win meter. In another embodiment, bonus wins are paid immediately following each free game.  
         [0037]     Each time one or more predetermined “decrement” symbols appear in free game play, the number of free games remaining on the counter will be decremented once for each such symbol. If no decrementing symbols appear during a particular free game, the counter does not decrement; in effect, the player is awarded an extra free game. When the counter reaches zero, free game play is terminated and the player is awarded any accumulated win on the bonus win meter through a payout device, by transference to a credit meter or by other similar means.  
         [0038]     The minimum number of free games awarded may be a random value. The reels used in the free games may contain the same symbols and weighted mapping as the base game reels or may contain different symbols and/or mapping as the base game reels. In the Rock Hound game, for example and not intended to be limiting in any way, the reels used in the free games have different symbols and weighting than the reels used in the base game.  
         [0039]     In another embodiment, a free games expended counter may be initialized to zero. Each time one or more predetermined symbols appear in free game play, the free games expended counter is incremented once for each such symbol. If no incrementing symbols appear during a particular free game, the counter does not increment; in effect, the player is awarded an extra free game. When the counter reaches the number of pre-awarded free games, free game play is terminated and the player is awarded any accumulated win as described above.  
         [0040]     The number of free games remaining or expended can be displayed in any fashion including, but not limited to, a numerical meter, a graphical meter or both. Rock Hound, for example, employs both a numerical meter and a graphical meter.  
         [0041]      FIGS. 5-10  provide an example of free game play in accordance with one aspect of the invention. Referring to  FIG. 5 , three “free spin” symbols  500  appear on the reels, triggering free game play. Turning to  FIG. 6 , the normal reels  301 - 305  of  FIG. 3  have been obscured, as shown on reels  601 - 605 , in preparation for the introduction of special bonus reels. Five free games have been awarded to the player and placed in counter  600 , represented both graphically, by storm icons  610 , and numerically, by indicator  620 .  
         [0042]     Continuing now with  FIG. 7 , free game play has begun as the dust from the reel-obscuring storms of  FIG. 6  is replaced by spinning free game reels  701 - 705 . Reels  701 - 704  are in mid-spin and reel  705  is just starting to spin. In this example, the free game reels spin horizontally. In other embodiments, the free game reels may also spin in the traditional vertical manner. In still other embodiments, the reels are spun bi-directionally. One example of bi-directional reel spins is disclosed in U.S. Pat. No. 5,251,898, entitled “Gaming Apparatus with Bi-directional Reels” which is hereby incorporated by reference.  
         [0043]     Proceeding to  FIG. 8 , free game play has continued into subsequent free games. The player has accumulated 135 credits in bonus wins, as shown on meter  850 . Numeric indicator  830 , free game icons  810  and expended free game icons  820  in free game meter  800  indicate that at least two free games remain to be played. Decrementing symbol  840  has caused one of the free game icons  810  to be replaced by an expended free game icon  820  and numeric indicator  830  to be decremented from 3 (not shown) to 2.  
         [0044]     Continuing to  FIG. 9 , free game play has continued into subsequent free games. 4 red jewel symbols  960  have caused the player to be awarded a bonus pay of 150 credits, as shown in message  970 . Decrementing symbol  940  has caused the last of the free game icons ( FIG. 8, 810 ) to be replaced by an expended free game icon  920 . The numeric indicator ( FIG. 8, 830 ) has been removed and the expended free game icons  920  in free game meter  900  show a total of at least five free games played. The player has accumulated 390 credits in bonus wins, as shown on meter  950 . The total bonus win will be transferred to the credit meter and the normal base game reels will be redrawn for resumption of normal play.  
         [0045]     A logical flow diagram generally depicting the steps associated with a method  1000  for carrying out a selectable bonus game in accordance with one aspect of the invention is presented in  FIG. 10 . The order of actions as shown in  FIG. 10  and described below is only illustrative, and should not be considered limiting. For example, the order of the actions may be changed, additional steps may be added or some steps may be removed without deviating from the spirit of the invention.  
         [0046]     The base game is initiated at Block  1005 . For example in a slot primary game, the player initiates play of the slot reels by inserting currency of some form, selecting the number of lines to play, the number of credits per line and presses a start switch or button. The reels are spun and the player may be awarded a base game award by the game or the game may trigger one or more free bonus games at Block  1010 .  
         [0047]     Regardless of win or loss in block  1010 , it is determined whether any free game bonus trigger combinations appear on the reels at decision block  1020 . If no triggering combination appears on the reels, processing returns to block  1005  and normal play continues, otherwise processing proceeds to block  1030 .  
         [0048]     A formula is applied to determine the number of free games to be awarded and the free game counter(s) are initialized, block  1030 . A free bonus game is presented and any resulting wins are paid, either immediately or to a win meter, in block  1040 .  
         [0049]     At decision block  1050 , it is determined if any decrementing symbols are present on the reels. If no decrementing symbols are present, processing returns to block  1040  and free game play continues, otherwise processing proceeds to block  1060 , where one free game remaining icon is replaced by one free game expended icon for each decrementing symbol on the reels and the numeric indicator of the minimum number of remaining free games is adjusted.  
         [0050]     The minimum number of free games remaining counter is examined at decision block  1070 . If the minimum number of free games remaining is not zero, free game processing continues at block  1040 , otherwise any credits on the bonus win meter are transferred to the game credit meter or otherwise paid at block  1080  and normal game play resumes at block  1005 .  
         [0051]     Referring to  FIG. 11 , in accordance with one aspect of the invention, gaming system  1100  includes server  1110 , gaming machines  1150 , and network  1140  connecting gaming machines  1150  to server  1110 . Additionally, gaming display computer  1130  is shown connected to network  1140 . Server  1110  may be selected from a variety of conventionally available servers. The type of server used is generally determined by the platform and software requirements of the gaming system. Examples of suitable servers are an IBM RS6000-based server, an IBM AS/400-based server or a Microsoft Windows-based server, but it should be appreciated that any suitable server may be used. It may also be appreciated that server  1110  may be configured as a single “logical” server that comprises multiple physical servers. Gaming machines  1150  operate similar to conventional peripheral networked terminals. Gaming machines  1150  have a player interface such as a display, a card reader, and selection buttons through which gaming machines  1150  interact with a player playing an open-ended bonus wagering game. The player interface is used for making choices such as the amount of a bet or the number of lines to bet. Gaming machines  1150  also provide information to server  1110  concerning activity on gaming machines  1150  and provide a communication portal for players with server  1110 . For example, the player interface may be used for selecting different server-related menu options such as, but not limited to, transferring a specified number of credits from a player account onto the credit meter of the gaming machine, or for transferring credits from the gaming machine to a central player account.  
         [0052]     In various embodiments, any of the gaming machines  1150  may be a mechanical reel spinning slot machine, video slot machine, video poker machine, keno machine, video blackjack machine, or a gaming machine offering one or more of the above described base games offering an open-ended bonus game. Networking components (not shown) facilitate communications across network  1140  between the system server  1110  and game management units  1120  and/or gaming display control computers  1130  that control displays for carousels of gaming machines. Game management units (GMU&#39;s)  1120  connect gaming machines to networking components and may be installed in the gaming machine cabinet or external to the gaming machine. The function of the GMU is similar to the function of a network interface card connected to a desktop personal computer (PC). Some GMU&#39;s have much greater capability and can perform such tasks as presenting and playing an open-ended bonus game using a display  1125  operatively connected to the GMU  1120 . Displays related to open-ended bonus games being played on gaming machines  1150  or GMU displays  1125  may also be presented on gaming display  1135  by gaming display control computer  1130 . In one embodiment, the GMU  1120  is a separate component located outside the gaming machine. Alternatively, in another embodiment, the GMU  1120  is located within the gaming machine. Optionally, in an alternative embodiment, one or more gaming machines  1150  connect directly to the network and are not connected to a GMU  1120 . A gaming system of the type described above also allows a plurality of open-ended bonus games to be linked under the control of server  1110  for cooperative or competitive play in a particular area, carousel, casino or between casinos located in geographically separate areas.  
         [0053]     One will appreciate that a gaming system may also comprise other types of components, and the above illustrations are meant only as examples and not as limitations to the types of components or games having an open-ended bonus game element in accordance with various embodiments of the invention in a gaming system. Additionally, it may further be appreciated that each of the games could be operated on a remote host computer such that a player initiates play with the host computer over a network via the player interface and gaming machine  850  operates the respective gaming and video displays in conjunction with the game whose play is controlled by the remote computer.  
         [0054]     Although the description above contains much specificity, it should not be construed as limiting the scope of the invention but as merely providing an illustration of the presently preferred embodiment of the invention. The various embodiments disclosed herein are directed to a system and method for providing an open-ended bonus game in a gaming device. Embodiments of the system, method and gaming device are illustrated and described herein by way of example only and not by way of limitation. Those skilled in the art will readily recognize various modifications and changes may be made to the invention without departing from the true spirit and scope of the claimed invention as set forth below.