Abstract:
A method for operating a game of chance comprises the steps: initiating a base game by a player; triggering a feature mode from the base game upon the occurrence of a first triggering event, wherein a first number of feature games are provided in the feature mode; playing the feature games in the feature mode, wherein each of the feature games has an opportunity to win a progressive award; and returning to the base game upon the termination of the feature games.

Description:
FIELD OF INVENTION 
       [0001]    This invention relates to gaming machines, and, in particular, to methods for a free game feature of a gaming machine, where the free game feature offers the possibility of winning progressive awards. 
       BACKGROUND 
       [0002]    Gaming machines, such as slot machines, video poker machines and the like, have been a cornerstone of the gaming industry for several years. Generally, the popularity of such machines with players depends on the likelihood (or perceived likelihood) of winning money at these machines and the intrinsic entertainment value of these machines relative to other available gaming options. Players are most likely to be attracted to the most entertaining and exciting machines. Shrewd operators consequently strive to employ the most entertaining and exciting machines available because such machines attract frequent plays and hence increase profitability for the operator. Accordingly, in the competitive gaming machine industry, there is a continuing need for gaming machine manufacturers to produce new types of games, or enhancements to existing games, which will attract frequent plays by enhancing the entertainment value and excitement associated with the games. 
         [0003]    One concept which has been successfully employed to enhance the entertainment value of a game is the concept of a “free” or “bonus” game which may be played in conjunction with a “base” game. The free game may comprise any type of game, either similar to or completely different from the base game, which is triggered upon the occurrence of a selected event or outcome of the base game. The free game is entered upon the appearance of a special symbol combination on the reels of the slot machine in the base game. One of the allures of the free game is that the player can play the free game to win an award without the risk of losing money since an additional wager is not needed to play the free game. 
         [0004]      FIG. 1  illustrates a typical slot machine. A typical slot machine  10  can have a display  14  for viewing motor-operated reels or video graphic reels. Furthermore, the slot machine  10  can have a lever  12  for initiating play (e.g., initiating a base game or initiating a free game of the slot machine  10 ). Alternatively, the slot machine  10  may have one or more buttons (not shown) on the slot machine  10  for initiating play. 
         [0005]      FIG. 2  illustrates a display of a slot machine having three pay lines and three display windows. A display  16  can have display windows  20 ,  22 , and  24 , where each display window displays three symbols for one of the reels. Three pay lines  30 ,  32 , and  34  intersect the display of these three symbols. If a winning combination of symbols is intersected along one of the pay lines, then the player is given an award. The pay lines  30 ,  32 , and  34  can be activated according to the base game and a wagered amount. 
         [0006]    The base game can comprise of matching a number of base symbols (which can be referred to as symbols) to a winning sequence. If a special combination of symbols, e.g., such as three bonus symbols, is drawn, then free game may be initiated. The free game can be played using the same reels and in the same game format. Additionally, a free game may be played on a different display or format, where the free game may have different rules from the base game. 
         [0007]    Generally, the expectation of winning coins or credits in the free game is much greater than that of the base game. Such a free game produces a significantly higher level of player excitement than the base game because it provides a greater expectation of winning than the base game and is accompanied with more attractive or unusual video displays and/or audio. 
         [0008]    Another concept which has been successfully employed to enhance the entertainment value of a game is the concept of progressive awards. Progressive awards can be accumulated by either a standalone machine or two or more slot machines linked together. A portion of each wager made on the one or more slot machines contribute to a common pool of one or more jackpots (e.g., tiers or levels). 
         [0009]    Various gaming methods can be used to win a progressive award, e.g., a mystery jackpot method, a symbol driven method, or a hybrid progressive award method. 
         [0010]    With respect to a mystery jackpot, the mystery jackpot gaming method can have a lower limit and an upper limit defined. A random number generator (“RNG”) draws a dollar amount between the two ranges. Since a percentage of each wager is contributed to the progressive award, a player wins the progressive award when the progressive award reaches the randomly generated dollar amount due to the player&#39;s wager. Thus, when the player deposits a “coin” that matches the predetermined jackpot value, then that player wins the progressive award. Generally, the slot machines state the range of the jackpot value that is guaranteed to be paid out. 
         [0011]    Symbol driven progressive awards are won when a player draws a specific symbol combination on a gaming machine. For instance, if three winning symbols are drawn, then the player can win a progressive award. 
         [0012]    For symbol driven progressive awards and for hybrid progressive awards, on any given handle pull, a determination is made as to whether or not a player has won a progressive award. Prior to winning, no indication is given to player. Progressive awards are paid out based on probabilities that over time will average out to the desired pay values per award. 
         [0013]    Because the free game concept and progressive awards offer tremendous advantages in player appeal and excitement relative to other known games, and because such games are attractive to both players and operators, there is a continuing need to develop new types of games to satisfy the demands of players and operators. Preferably, such new games will maintain, or even further enhance, the level of player excitement offered by free games heretofore known in the art. Therefore, there exists a need to further implement new games for enticing and satisfying player&#39;s needs. In particular, it is of great need to merge the free game concept with a progressive award concept to further attract and entertain players. 
       SUMMARY OF INVENTION 
       [0014]    An object of this invention is to provide methods for operating a gaming machine where progressive awards are won in a free game feature. 
         [0015]    Another object of this invention is to provide methods for operating a gaming machine where a player has multiple opportunities to win progressive awards in a game feature and where the probability of winning the progressive awards is a function of the amount of the wager. 
         [0016]    Yet another object of this invention is to provide methods for operating a gaming machine where a player is eligible to win multiple progressive awards within a single free game feature mode. 
         [0017]    Furthermore, another object of this invention is to provide methods for operating a gaming machine where unique progressive triggering symbols are added to a free game feature and can be substituted for corollary hierarchical symbols. 
         [0018]    Even more so, another object of this invention is to provide methods for operating a gaming machine where progressive awards and base pay-table awards can be won in a free game feature mode. 
         [0019]    Briefly, a method for operating a game of chance comprises the steps: initiating a base game by a player; triggering a feature mode from the base game upon the occurrence of a first triggering event, wherein a number of feature games are provided in the feature mode; playing the feature games in the feature mode, wherein each of the feature games has an opportunity to win a progressive award; and returning to the base game upon the termination of the feature games. 
         [0020]    An advantage of this invention is that methods are provided for operating a gaming machine, where progressive awards are won in a free game feature. 
         [0021]    Another advantage of this invention is that methods are provided for operating a gaming machine where a player has multiple opportunities to win progressive awards in a free game feature and where the probability of winning the progressive award is a function of the amount of the wager. 
         [0022]    Yet another advantage of this invention is that methods are provided for operating a gaming machine where a player is eligible to win multiple progressive awards within a single free game feature mode. 
         [0023]    Furthermore, another advantage of this invention is that methods are provided for operating a gaming machine where unique progressive triggering symbols are added to a game feature and can be substituted for corollary hierarchical symbols. 
         [0024]    Even more so, another advantage of this invention is that methods are provided for operating a gaming machine where progressive awards and base pay-table awards can be won in a free game feature mode. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0025]    The foregoing and other objects, aspects, and advantages of the invention will be better understood from the following detailed description of the preferred embodiment of the invention when taken in conjunction with the accompanying drawings in which: 
           [0026]      FIG. 1  illustrates a slot machine. 
           [0027]      FIG. 2  illustrates a display of a slot machine having three pay lines and three display windows. 
           [0028]      FIG. 3  illustrates a linked system of slot machines for earning progressive awards. 
           [0029]      FIG. 4  illustrates a display of a slot machine having five pay lines and five display windows. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0030]    A symbol driven progressive award gaming system is disclosed, whereby one or more tiers of progressive awards can be won inside a feature mode where one or more feature games (e.g., a free game or a bonus game) may be played. During the play of a feature game such as a free game, other free games can be awarded in addition to the possibility of winning an award based on a pay table for the base game or based on a progressive award pay table. 
         [0031]    Generally, a base game comprises a wager and subsequent outcomes. A feature mode can be an event that occurs as a result of one or more outcomes whereby the player is awarded an opportunity to win awards without wagering additional cash or credits. Furthermore, the base game can have a base game pay table for listing winning combinations and sequences and the amount of the award. 
         [0032]    As stated earlier, progressive awards can be accumulated by either a standalone machine or two or more slot machines linked together. A portion of each wager made on the one or more slot machines contribute to a common pool of one or more jackpots (e.g., progressive tiers or progressive levels). 
         [0033]      FIG. 3  illustrates a linked system of slot machines for earning progressive awards. Several slot machines can be connected to a linked gaming system. The gaming system can track the amount of the progressive awards and determine when the progressive awards are won. The progressive award can be won during the feature game of the base game and can be dependent on the wager placed in the base game. 
         [0034]    The feature mode (to play the feature games, e.g. free games) can be triggered by one or more triggering symbols. When the triggering symbols are drawn, then a feature game (in the feature mode) can be initiated, wherein a progressive award can be earned by the player. 
         [0035]    Each spin of the reels can possibly win at any of the progressive pay out levels, such that N number of free games can have N number of chances to win at any progressive level. For instance, if the player triggers three feature games (e.g. free games) from the base game, then the player has the opportunity to win at the progressive level three times. Furthermore, more feature games (e.g. free games) can be triggered while playing at the progressive level, thus adding additional free games to the total number of free games remaining to be played. Winning free games during the free game feature (or progressive level) can be referred to as retriggering. Once a progressive award is won, then the progressive award can be reset. 
         [0036]      FIG. 4  illustrates a display of a slot machine having five pay lines and five display windows. A display  40  of a slot machine can have five display windows  44 ,  46 ,  48 ,  50 , and  52 , where each display window displays five symbols from one of the reels. A first reel can be associated and displayed on the display window  44 . A second reel can be associated and displayed on the display window  46 . A third reel, a fourth reel, and a fifth reel can also be associated and displayed on the display windows  48 ,  50 , and  52  in a similar manner. Five pay lines  54 ,  56 ,  58 ,  60 , and  62  intersect the five symbols of each of the display windows  44 ,  46 ,  48 ,  50 , and  52 . The pay lines  54 ,  56 ,  58 ,  60 , and  62  can be activated according to the wagered amount. 
         [0037]    It can be appreciated by a person having ordinary skill in the art that the number of reels, display windows, and pay lines can vary depending on the design parameters of the slot machine. To aid in the understanding of the invention, the disclosure may use a slot machine having five reels, five windows, and five pay lines in describing the invention. However, it is understood that the present invention can be applied to any number of reels, any number of windows, and any number of pay lines. Furthermore, each display window can display a predefined number of symbols for one of the reels. 
         [0038]    The present invention can also apply to a mechanical display and a video display. In addition, the video display slot machine may not have a lever, display windows, reels and/or other physical components that are typically associated with a mechanical display slot machine. 
         [0039]    If the base game triggering symbols (which can be denoted TS 1 , TS 2 , TS 3 , and so forth to TSN) are drawn, then the feature mode for playing the feature games (e.g. free games) can be triggered. The number of triggering symbols and the sequence of the triggering symbols can be designed in various combinations to trigger the free game feature. For instance, a free game feature can be triggered by matching the triggering symbol TS 1  on three consecutive reels. Alternatively, a free game feature can be triggered by requiring a specific sequence of symbols be drawn. An example of a specific sequence of symbols can be where the triggering symbol TS 1  is on the first reel, the triggering symbol TS 2  is on the second reel, the triggering symbol TS 3  is on the third reel, the triggering symbol TS 4  is on the fourth reel, and the triggering symbol TS 5  is on the fifth reel. Thus, if the triggering symbol TS 1  is not on the first reel, but the triggering symbols TS 2 , TS 3 , TS 4 , and TS 5  are on the second, third, fourth, and fifth reels, respectively, then the free game feature would not be triggered. 
         [0040]    Once the free game feature has been triggered, a number of feature games (e.g. free games) are allotted to the player (e.g., 12 free games). The number of feature games can be randomly generated or predefined. In the free game feature, the reels may automatically draw consecutive free games for the player without any further player interaction. Each draw can win a base game award, a progressive award, and/or additional free games. As soon as the reels resolve a draw, any earnings awarded are tallied to a total award for that free game feature. Once all the free games are exhausted, the total award (if any) is credited to the player, and the base game resumes. 
         [0041]    The number of feature games (e.g. free games) earned during one draw of a base game or a free game can be dependent on the design parameters of the slot machine and on the number and sequence of triggering symbols. For instance, if three identical triggering symbols are drawn, then three free games can be awarded. If there are four identical triggering symbols drawn, then ten free games can be awarded. Thus a tiered system can be implemented for awarding the free games, where the more triggering symbols that are matched (either by number or sequence), the more free games are awarded to the player. Furthermore, if a specific sequence of triggering symbols can also be awarded a predefined number of free games. For instance, twelve free games can be awarded when the triggering symbols TS 1 , TS 2 , and TS 3  are on the first three reels, respectively. 
         [0042]    Once a player has triggered the feature mode to play the feature games, the player gets a number, N, opportunities to win one or more symbol driven progressive awards. In addition to having a chance to win the progressive awards, the player can win a fixed value from the pay table of the base game. 
         [0043]    There can be multiple pay out levels depending on the initial wager in the base game and depending on the rules of the slot machine. The game play for a free game can be the same as the base game, an entirely different game than the base game, or a variation of the base game. 
         [0044]    In a variation of the base game, the aesthetics of the game may change, e.g., the background may change or symbols may change. Additionally, more symbols (e.g., progressive symbols) can be added and a “sweetener” can be included such that the pay table awards are paid out at a higher value. 
         [0045]    For instance, Table 1 illustrates a sample pay table that states the pay levels (e.g., grand, major, minor, and mini) and the combinations of symbols needed to win an award. 
         [0000]    
       
         
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
               
                 Pay Out 
                   
                   
                   
                   
               
               
                 Level 
                 Base Game 
                 Award 
                 Free Game 
                 Award 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 Grand 
                   
                   
                 Five S1p Symbols 
                 Grand Progressive Award 
               
               
                   
                 Five S1 Symbols 
                 5000 
                 Five S1 and S1p Symbols 
                 5000 
               
               
                   
                 Four S1 Symbols 
                 1000 
                 Four S1 and S1p Symbols 
                 1000 
               
               
                   
                 Three S1 Symbols 
                 100 
                 Three S1 and S1p Symbols 
                 100 
               
               
                 Major 
                   
                   
                 Five S2p Symbols 
                 Major Progressive Award 
               
               
                   
                 Five S2 Symbols 
                 700 
                 Five S2 and S2p Symbols 
                 700 
               
               
                   
                 Four S2 Symbols 
                 150 
                 Four S2 and S2p Symbols 
                 150 
               
               
                   
                 Three S2 Symbols 
                 30 
                 Three S2 and S2p Symbols 
                 30 
               
               
                 Minor 
                   
                   
                 Five S3p Symbols 
                 Minor Progressive Award 
               
               
                   
                 Five S3 Symbols 
                 500 
                 Five S3 and S3p Symbols 
                 500 
               
               
                   
                 Four S3 Symbols 
                 100 
                 Four S3 and S3p Symbols 
                 100 
               
               
                   
                 Three S3 Symbols 
                 25 
                 Three S3 and S3p Symbols 
                 25 
               
               
                 Mini 
                   
                   
                 Five S4p Symbols 
                 Mini Progressive Award 
               
               
                   
                 Five S4 Symbols 
                 500 
                 Five S4 and S4p Symbols 
                 500 
               
               
                   
                 Four S4 Symbols 
                 100 
                 Four S4 and S4p Symbols 
                 100 
               
               
                   
                 Three S4 Symbols 
                 25 
                 Three S4 and S4p Symbols 
                 25 
               
               
                   
               
             
          
         
       
     
         [0046]    The top four paying symbols, which can be denoted S 1 , S 2 , S 3 , and S 4  for any particular base game, are listed in order of pay out level for the base game pay table. Furthermore, progressive symbols, which can be denoted S 1   p , S 2   p , S 3   p , and S 4   p , can be used for earning a progressive award. The progressive awards are similarly listed in order of pay out levels for the progressive award. 
         [0047]    Thus for a game that has twelve distinct symbols, the top four symbols for the base game pay table, listed in order of pay out level, are symbols S 1 , S 2 , S 3 , and S 4 . Based on Table 1, if three S 1  symbols are drawn, the player is awarded 100 credits. The base game may require that the S 1  symbols be on sequential reels, such as on the first reel, the second reel, and the third reel. 
         [0048]    During the feature mode in playing the feature games (e.g. a free game feature), if a player gets five S 1   p  symbols containing no wilds, then the player can win the progressive award. Furthermore, the S 1  symbols can substitute as wild symbols for the S 1   p  symbols in the free game pay table. Thus, if the player gets a pay line having five symbols comprising S 1  and S 1   p  symbols, then the player is awarded the grand level award of 5,000 credits according to the free game pay table. 
         [0049]    The progressive symbols S 1   p -S 4   p  can be mapped to any symbol driven game, regardless of the game type. For instance, once the feature mode is initiated, the progressive symbols can replace symbols from the base game. The free game can be performed using the reels from the base game with additional progressive symbols. Thus, the free game feature can yield awards based on the base game pay table and the progressive award pay table. 
         [0050]    A weighted table for each bet level and for each reel determines if a symbol (“SN”) or a progressive symbol (“SNp”) is displayed. The progressive symbol can be an entirely different symbol or correspond to a symbol of the base game. The only requirement may be that there is a minimum number of progressive symbols in the free game, e.g., five progressive symbols. Additionally, a pay out table can have awards for a mix of the base game symbols, the progressive symbols, and/or wild symbols. Wild symbols can be substituted for one or more other symbols to earn a payout. 
         [0051]    In terms of the frequency for awarding pay outs, the feature game is structured and designed with targeted progressive award amounts and an estimated duration of time or wagers between wins for each level. This is accomplished by using a set of mathematic probabilities calculated against a pre-determined number of machines designated for the free game feature and the anticipated average play when deployed in the casino. 
         [0052]    Table 2 illustrates typical targets for a feature game (e.g. a free game). 
         [0000]    
       
         
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
             
           
               
                 TABLE 2 
               
               
                   
               
               
                   
                   
                   
                   
                   
                 Games at 
                   
               
               
                   
                   
                   
                   
                   
                 Min Bet All 
               
               
                 Pay Out 
                   
                 Hit Goal 
                 Handle to 
                 Games at 
                 Ways and 
                 Games at 
               
               
                 Level 
                 Reset 
                 [Days] 
                 Hit 
                 Min Bet 
                 Lines 
                 Max Bet 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 Grand 
                 $300,000 
                 30 
                 $9,600,000 
                 48,000,000 
                 1,920,000 
                 192,000 
               
               
                 Major 
                 $50,000 
                 15 
                 $4,800,000 
                 24,000,000 
                 960,000 
                 96,000 
               
               
                 Minor 
                 $10,000 
                 3 
                 $960,000 
                 4,800,000 
                 192,000 
                 19,200 
               
               
                 Mini 
                 $1,000 
                 0.333 
                 $106,560 
                 532,800 
                 21,312 
                 2,131 
               
               
                   
               
             
          
         
       
     
         [0053]    The name and number of progressive tiers or levels can be varied. The progressive levels can be named a grand level, a major level, a minor level, and a mini level. The reset value is the minimum value that can be won for the corresponding progressive level. The hit goal can give the minimum number of days that the progressive level is likely to be awarded under average playing conditions, where a minimum amount of money must be wagered on each gaming machine. The handle is the minimum amount of money handled by the slot machines before the progressive level is likely to be awarded to a player. The number of games at minimum bet indicates the number of games at a minimum bet level (which can be set to one credit) before for the progressive level is likely to be awarded. Games at minimum bet all ways and lines gives the number of games played with all the pay lines activated before the progressive level award is likely to be won. The games at maximum bet states the number of games played at maximum bet per line before a progressive pay out is likely to be awarded. 
         [0054]    Table 3 illustrates typical parameters for the feature mode for playing the feature game(s) (e.g. a free game). 
         [0000]    
       
         
               
               
               
             
           
               
                   
                 TABLE 3 
               
               
                   
                   
               
             
             
               
                   
                 Credit Value 
                 $0.20 
               
               
                   
                 Min Bet Credits 
                 1 
               
               
                   
                 Min Bet Credits All Ways and Lines 
                 25 
               
               
                   
                 Max Bet 
                 250 
               
               
                   
                 Estimated Handle [Daily/EGM] 
                 $20,000 
               
               
                   
                 Link Size [EGM] 
                 16 
               
               
                   
                 Min Bet 
                 $0.20 
               
               
                   
                 Min All Ways and Lines 
                 $5.00 
               
               
                   
                 Max Bet 
                 $50.00 
               
               
                   
                 Average System Handle [Daily] 
                 $320,000 
               
               
                   
                   
               
             
          
         
       
     
         [0055]    The credit value of 1 credit can be 20 cents. The max bet per line can be set at 25 credits. Thus, if there are ten possible pay lines, then the total max bet can be set at 250 credits. The estimate handle is the estimated handle per day for an electronic gaming machine (“EGM”) deployed on an EGM linked system. Thus, the estimated handle for each EGM per day is 20K dollars. The link size is the number of machines deployed in the EGM linked system. In this example, 16 machines can be deployed together. Thus, the average system handle (i.e., total handle for the 16 EGMs) is 16 times 20,000, which is about 320,000 dollars. 
         [0056]    The various stated amounts in Table 3 are merely illustrative of typical parameters for an EGM. It is to be understood that other amounts of money and various currencies can be used in conjunction with the present invention. 
         [0057]    An underlying mathematical function can be employed to guarantee the likelihood of the operating parameters stated in the tables above. Furthermore, the mathematical functions can also take into account the amount wagered by the player, such that the higher the wager, the greater the chance for winning a progressive award. 
         [0058]    In one embodiment, the probability for winning a progressive award can be governed by the multiplication of the following four probabilities. 
         [0059]    The first probability is the probability of getting into the feature mode (e.g. a free game), which is determined by the weighted reel strips. This probability is always a fixed probability regardless of wager since it is dependent on the number of symbols, the weight for each of the symbols, and the number of reels. 
         [0060]    The second probability is the probability of the reel strips for landing on the symbols S 1 , S 2 , S 3 , or S 4 . This probability is also a fixed probability. 
         [0061]    The third probability is the probability for converting symbols S 1 , S 2 , S 3  and S 4  into their progressive symbol counterparts. This probability is tiered against a number of pay lines or reels and bet per pay line or reel wagered. For instance, the higher the number of pay lines or reels or bet per pay line or reel wagered, the higher the chance for progressive symbol conversion. 
         [0062]    During the free game, the player can draw the symbols S 1 -S 4 . The symbols S 1 -S 4  can be converted into their progressive symbol counterparts, i.e., S 1   p -S 4   p . In an example, if a pay line tentatively draws five S 1  symbols, a set probability can be applied to converting each of the drawn symbols to its progressive symbol counterpart. The probability for converting drawn symbols can be based on the wagered amount, such that the greater the wager, the greater the probability of converting a symbol to its progressive symbol counterpart. Thus, a sliding scale can be established where base game symbols can be converted to their progressive symbol counterparts. 
         [0063]    The probability for conversion can be dependent on a genetic algorithm, which can be applied to gambling. In such algorithm, a scaled probability based on wagers and the frequency of hand folds can be used to determine the probability of an award. Thus, as the progressive award increases in value, the player is guaranteed to get a linear increase of near-misses during the free game feature. In addition, other dynamic probability algorithms or mutative algorithms can be used for determining a probabilistic value for conversion of symbols to their progressive symbol counterparts. 
         [0064]    The fourth probability can be the probability for S 1 , S 2 , S 3 , and/or S 4  symbols to draw in a specific sequence on a pay line or pay combination. For instance, increasing the number of lines or reels wagered can increase the possibility of progressive eligible symbols landing in positions within a wagered pay line or reel. 
         [0065]    While the present invention has been described with reference to certain preferred embodiments or methods, it is to be understood that the present invention is not limited to such specific embodiments or methods. Rather, it is the inventor&#39;s contention that the invention be understood and construed in its broadest meaning as reflected by the following claims. Thus, these claims are to be understood as incorporating not only the preferred methods described herein but all those other and further alterations and modifications as would be apparent to those of ordinary skilled in the art.