Patent Publication Number: US-2009239643-A1

Title: Slot machine and control method thereof

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is based upon and claims the benefit of U.S. Provisional Application No. 61/038,204, filed on Mar. 20, 2008; the entire contents of which are incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a slot machine and a control method thereof with which a player plays a game by using medals, coins, bills and the like. 
     2. Description of Related Art 
     U.S. Pat. No. 7,309,282 and U.S. Pat. No. 7,311,602B2 disclose related slot machines. Such related slot machines are configured to: start to rotate multiple reels when a player operates a spin switch after inserting medals, coins or bills into an insertion slot of the slot machine and making a bet of credits by using a BET switch; and then sequentially stop rotating the reels. 
     A side face of each of the reels is provided with a reel band on which multiple symbols are printed, and the multiple symbols are displayed on display region provided on a front face of a cabinet when all the reels stop rotation. Then, a winning award according to the bet is provided when multiple symbols form a specific combination. 
     Such related slot machines are simply configured to provide a winning award according to a bet when multiple symbols forms a specific combination and is therefore apt to render games monotonous. Accordingly, there has been a demand for providing a slot machine that offers more excitement to players. 
     SUMMARY OF THE INVENTION 
     A first aspect of the present invention provides a slot machine comprising: (a) a display provided with display regions to arrange and display a plurality of symbols; (b) a bet switch configured to receive a bet from a player; and a controller configured to: (A) execute a slot game upon receipt of an external input, by rearranging the symbols arranged in the display regions, and by granting a winning award if a predetermined number of symbols of a predetermined type are displayed; and (B) when rearranging the symbols, control the display to change targeted-symbol display regions within the display regions according to an amount of bet received by the bet switch, the targeted-symbol display regions being targeted for counting a number of symbols of the predetermined type. 
     A second aspect of the present invention provides a slot machine comprising: (a) a plurality of rotatable reels each including a plurality of symbols on a side surface; (b) a display being disposed at front face sides of the reels and including an image display region having display regions to display the symbols on the plurality of reels; (c) a bet switch configured to receive a bet from a player; and a controller configured to: (A) execute a slot game upon receipt of an external input, by rotating and then stopping the reels to rearrange the symbols arranged in the display regions, and by awarding a winning if a predetermined number of symbols of a predetermined type are displayed; and (B) when rearranging the symbols, control the display to change targeted-symbol display regions within the display regions according to an amount of bet received by the bet switch, the targeted-symbol display regions being targeted for counting a number of symbols of the predetermined type. 
     A third aspect of the present invention provides a method of controlling a slot machine comprising the steps of: (a) causing a bet switch to receive a bet from a player; (b) causing a controller to rotate a plurality of reels each including a plurality of symbols on a side surface; (c) along with rotation of the reels, causing the controller to display an image on a display being disposed on front face sides of the reels and including an image display region having a symbol display region for displaying the symbols on the plurality of reels, so that the targeted-symbol display regions within the symbol display region change according to an amount of bet received by the bet switch; (d) causing the controller to stop the rotating reels; and (e) causing the controller to grant a winning award if a predetermined number of symbols of a predetermined type are displayed in the targeted-symbol display regions. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a view for explaining an example of symbols to be displayed on a display of a slot machine according to an embodiment of the present invention. 
         FIG. 1B  is a view for explaining award relevant to the symbols displayed on the display of the slot machine according to the embodiment. 
         FIG. 2A  is another view for explaining an example of the symbols to be displayed on the display of the slot machine according to the embodiment. 
         FIG. 2B  is another view for explaining the award relevant to the symbols displayed on the display of the slot machine according to the embodiment. 
         FIG. 3A  is another view for explaining an example of the symbols to be displayed on the display of the slot machine according to the embodiment. 
         FIG. 3B  is another view for explaining the award relevant to the symbols displayed on the display of the slot machine according to the embodiment. 
         FIG. 4  is a view showing an overall configuration of a slot machine according to the embodiment. 
         FIG. 5  is a block diagram showing an internal configuration of the slot machine according to the embodiment. 
         FIG. 6  is a view showing display region to be set up on a display of the slot machine according to the embodiment. 
         FIG. 7  is a flowchart showing a slot game execution process by the slot machine according to the embodiment. 
         FIG. 8  is a flowchart showing an image effect control process by the slot machine according to the embodiment. 
         FIG. 9  is a flowchart showing a provision process by the slot machine according to the embodiment. 
         FIG. 10  is a block diagram showing an internal configuration of a slot machine according to a modified example of the embodiment. 
         FIG. 11  is a perspective view of a display used in the slot machine according to the modified example of the embodiment. 
         FIG. 12  is an exploded perspective view of the display used in the slot machine according to the modified example of the embodiment. 
         FIG. 13A  is a view showing another example of the symbols to be displayed on the display of the slot machine according to the embodiment. 
         FIG. 13B  is a view showing still another example of the symbols to be displayed on the display of the slot machine according to the embodiment. 
         FIG. 13C  is a view showing yet another example of the symbols to be displayed on the display of the slot machine according to the embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENT 
       FIG. 1A  to  FIG. 3B  are views for explaining an example of symbols to be displayed on a display of a slot machine and provision according to the embodiment.  FIG. 1A  shows the example of the displayed symbols in the case of a small bet amount,  FIG. 2A  shows the example of the displayed symbols in the case of a medium bet amount, and  FIG. 3A  shows the example of the displayed symbols in the case of a maximum bet amount. Meanwhile,  FIG. 1B  shows the example of the provision in the case of the small bet,  FIG. 2B  shows the example of the provision in the case of the medium bet amount, and  FIG. 3B  shows the example of the provision in the case of the maximum bet amount. 
       FIG. 4  is an external view of the slot machine according to the embodiment and  FIG. 5  is a block diagram showing an electrical configuration of the slot machine according to the embodiment. 
     According to the slot machine of the embodiment, when a bet in a desired amount is made by a player and a slot game is executed by pressing a start switch  27 , three rows and five columns of symbols, i.e., a total of 15 symbols displayed in display region q 1   a  to q 3   e  on a display  16  shown in  FIG. 4  start scrolling. Then, the symbols are stopped (the arranged symbols are rearranged) after a predetermined time period. Some of the display regions q 1   a  to q 3   e  are displayed as targeted-symbol display regions, and the targeted-symbol display regions are designed to change according to the amount of bet made by the player. The targeted-symbol display regions here are regions targeted for counting the number of each of predetermined types of symbols. A provision is determined in accordance with a provision table shown in  FIG. 1B  and how many symbols of each of the predetermined types are displayed in the targeted-symbol display regions. 
     Specifically, the targeted-symbol display regions occupy three columns from the left in the case of the small bet amount as shown in  FIG. 1A , for example. Meanwhile, the targeted-symbol display regions occupy four columns from the left in the case of the medium bet amount as shown in  FIG. 2A  and the targeted-symbol display regions occupy all the columns (five columns) in the case of the maximum bet amount as shown in  FIG. 3A . Here, as shown in  FIG. 1A , the targeted-symbol display regions (the three columns on the left) are brightly displayed as usual while regions other than the targeted-symbol display regions (the two columns on the right) are darkly displayed, so that the range of the targeted-symbol display regions (the three columns on the left) is displayed as clearly recognizable to the player. Nevertheless, the regions other than the targeted-symbol display regions (the two columns on the right) are also displayed as discernible to the player. 
     Moreover, according to the slot machine of the embodiment, number of advantageous symbols (high class symbols) is gradually increased toward the right side of the display region as shown in  FIG. 1A ,  FIG. 2A , and  FIG. 3A . 
     Specifically, as shown in  FIG. 1B  to  FIG. 3B , 20 coins is provided when 3 symbols X with illustration of “killer whale” representing the highest provision possibility (see  FIG. 2A ) displayed in the targeted-symbol display regions, and 5000 coins is provided when 9 symbols X with illustration of “killer whale” displayed in the targeted-symbol display regions. Meanwhile, 2 coins is provided when 3 symbols Y with illustration of “Q” representing the lowest provision possibility (see  FIG. 2A ) displayed in the targeted-symbol display regions, and 600 coins is provided when 9 symbols Y with illustration of “Q” displayed in the targeted-symbol display regions. 
     Moreover,  FIG. 1B  covers only the three columns on the left as the targeted-symbol display regions, and the symbols displayed in the targeted-symbol display regions in this case are limited to those not shaded in the provision table. Specifically, an image effect to be displayed on the display  16  is controlled in a manner to reduce the probabilities of displaying symbols “killer whale”, “dolphin”, and “seal” that represent higher provision possibilities. 
       FIG. 2B  covers the four columns on the left as the targeted-symbol display regions, and the symbols displayed in the targeted-symbol display regions in this case are limited to those not shaded in the provision table. Specifically, the symbols “killer whale”, “dolphin”, and “seal” that represent higher provision possibilities are more frequently displayed on the right end column. 
       FIG. 3B  covers all the columns as the targeted-symbol display regions which are applied to the case of the maximum bet amount. There are no shaded sections on the provision table and a very high provision can be expected in this case. 
     In other words, the process to change the targeted-symbol display regions in response to the accepted bets is the process to increase the targeted-symbol display regions in accordance with an increase in the number of bets. Moreover, the display mode on the display is controlled so as to increase the targeted-symbol display regions in accordance with the increase in the amount of bet received by a bet switch. 
     Further, the display mode on the display is controlled so as to display a fewer number of the symbols providing the higher provision possibilities in the targeted-symbol display regions when receiving a small amount of bet and to display a larger number of the symbols providing the higher provision possibilities in the targeted-symbol display regions when receiving a large amount of bet. In this way, a certain symbol is randomly selected and arranged in each of the targeted-symbol display regions that are to increase according to an increase in the bet amount. In this case, along with the increase in the bet amount, the displaying of symbols is controlled in reference to different table data. 
     This slot machine has an effect to offer more advantages along the increase in the amount of bet to be made. Therefore, the slot machine can attract the player&#39;s interest in betting actions and thereby to improve entertainment properties. 
     Specifically, the player can also recognize the symbols in the regions other than the targeted-symbol display regions. Here, if the symbols are rearranged as shown in  FIG. 1A , for example, no provision is provided because there is no combination of three or more symbols of the same type rearranged in the targeted-symbol display regions. However, the player will notice that three dolphin symbols would have been rearranged in the targeted-symbol display regions, and he or she would have been able to receive a provision equivalent to 15 coins if he or she had made the maximum bet. As a consequence, the player may wish to increase the amount of bet thereafter. In this way, it is possible to attract the player&#39;s interest in betting actions. 
     Here, the targeted-symbol display regions (the three columns on the left) are brightly displayed as usual while the regions other than the targeted-symbol display regions (the two columns on the right) are darkly displayed as shown in  FIGS. 1A and 2A . However, as other display examples, it is also possible to display the enclosure image which surrounds the targeted-symbol display regions so as to notify that the regions surrounded by the enclosure image represent the targeted-symbol display regions as shown in  FIGS. 13A ,  13 B, and  13 C. That is, it is possible to apply any display method so far as such a method can appropriately notify the player of the targeted-symbol display regions. 
     Next, a configuration of a slot machine  10  of this embodiment will be described more in detail. As shown in  FIG. 4 , the slot machine  10  of this embodiment includes a cabinet  11 , a top box  12  provided on an upper side of the cabinet  11 , and a main door  13 . The cabinet  11  is provided with the display  16  placed on a face opposed to a player. Moreover, various constituent members such as a controller  40  (see  FIG. 5 ) configured to electrically control this slot machine  10  and a hopper  44  (see  FIG. 5 ) configured to control insertion, storage, and discharge of medals are provided inside the cabinet  11 . 
     While medals are used as an example of game media used for executing a game in this embodiment, the game media are not limited only to the medals. For example, it is also possible to use coins, tokens, electronic money, or other electronic value information (credits) corresponding thereto. 
     The main door  13  is openably and closably fitted to the cabinet  11 , and the display  16  of a liquid crystal display device or the like is provided substantially in the center of the main door  13 . As will be described later, the display  16  is adapted to display images concerning various games including the slot game. Symbols disposed in the  15  display region q 1   a  to q 3   e  arranged in the matrix of three rows and five columns as shown in  FIG. 5  are scrolled and then stopped (the arranged symbols are rearranged) in a slot game. 
     Here, as shown in  FIG. 6 , the suffixes a to e attached to the display region q indicate the columns while the suffixes  1  to  3  indicate the rows. Although the display region used for execution of the slot game is formed of the matrix including three rows and five columns in this embodiment, the present invention is not limited only to this configuration. 
     Meanwhile, a provision amount display region  48  adapted to display an amount of provision is provided in a lower left region of the display  16  shown in  FIG. 4 . 
     A medal insertion slot  21  configured to allow insertion of medals used for playing the slot game and a bill validator  22  configured to validate appropriate bills and to accept authentic bills are provided below the display  16 . Moreover, various operation switches are provided in the vicinity of the medal insertion slot  21  and the bill validator  22 . 
     A cash-out switch  23 , a MAXBET switch  24 , a BET switch  25 , a spin repeat BET switch  26 , and the start switch  27  are provided as the operation switches. 
     The BET switch  25  is the switch for deciding the amount of credits to be bet on a slot game executed on the display  16 . A credit equivalent to one medal is bet every time pressing the BET switch  25 . 
     The spin repeat BET switch  26  is the switch for executing a slot game by betting credits without changing the amount of credits bet in the previous game by using the BET switch  25 . 
     The start switch  27  is the switch for starting the slot game on the display  16  after making a bet of credits. The slot game is started in each of the display regions q 1   a  to q 3   e  on the display  16  when this start switch  27  is pressed down after inserting the medals to the medal insertion slot  21  or making the bet of credits by using the BET switch  25 . 
     The cash-out switch  23  is the switch for cashing out the inserted medals. The medals to be cashed out are discharged from a medal provision opening  28  provided at a lower part on the front face of the main door  13 . The discharged medals are pooled in a medal tray  18 . 
     The MAXBET switch  24  is the switch for betting the maximum amount of credits (such as credits corresponding to thirty medals) that the player can bet in one game session in a single operation. 
     A foot display  34  is provided on the lower part of the front face of the main door  13  and is adapted to display various images concerning the games with the slot machine  10 . The images include characters of the slot machine  10 , for example. 
     Lamps  47  are provided on both sides of the foot display  34  and are configured to emit light based on a preset light emission pattern corresponding to the playing condition of the slot machine  10 . The medal provision opening  28  is provided below the foot display  34 . 
     An upper display  33  is provided on a front face of the top box  12 . 
     Moreover, the top box  12  is provided with a speaker  29 . A ticket printer  35 , a card reader  36 , a data display  37 , and a keypad  38  are provided on a lower side of the upper display  33 . The ticket printer  35  is configured to print a bar code, which represents encoded data on the amount of credits, date and time, an identification number of the slot machine  10  and the like, on a ticket and to output a bar coded ticket  39 . 
     A player may allow another slot machine to read the bar coded ticket  39  and to play games with that slot machine or exchange the bar coded ticket  39  with money bills and the like at a predetermined location in a gaming arcade (such as a cashier in a casino). 
     The card reader  36  allows insertion of a smart card and is configured to read data out of the inserted smart card and to write data into the smart card. The smart card is a card carried by the player, which stores data for identifying the player, data concerning a history of games played by the player, and the like. 
       FIG. 5  is a block diagram showing an electrical configuration of a controller  40  provided in the slot machine  10  of this embodiment and various devices to be connected to this controller  40 . The controller  40  of the slot machine  10  shown in  FIG. 4  is a microcomputer which includes an interface circuit group  102 , an input-output bus  104 , a CPU (central processing unit)  106 , a ROM (read-only memory)  108 , a RAM (random access memory)  110 , a communication interface circuit  111 , a random number generating circuit  112 , a speaker driving circuit  122 , a hopper driving circuit  124 , a display driving circuit  128 , and a display controller  140 . 
     The interface circuit group  102  is connected to the input-output bus  104  and this input-output bus  104  inputs and outputs data signals and address signals to and from the CPU  106 . 
     The start switch  27  is connected to the interface circuit group  102 . A start signal outputted from this start switch  27  is converted into a given signal by the interface circuit group  102  and is then transmitted to the CPU  106  through the input-output bus  104 . 
     Further, the BET switch  25 , the MAXBET switch  24 , the spin repeat BET switch  26 , and the cash-out switch  23  are connected to the interface circuit group  102 . Moreover, each switching signals outputted from these switches  25 ,  24 ,  26 , and  23  are supplied to the interface circuit group  102 , then converted into given signals by this interface circuit group  102 , and then transmitted to the CPU  106  through the input-output bus  104 . 
     In addition, a medal detecting sensor  43  is connected to the interface circuit group  102 . The medal detecting sensor  43  is the sensor for detecting the medals inserted to the medal insertion slot  21 , and is provided at a medal insertion region of the medal insertion slot  21 . A detection signal outputted from this medal detecting sensor  43  is supplied to the interface circuit group  102 , then converted into a given signal by this interface circuit group  102 , and then transmitted to the CPU  106  through the input-output bus  104 . 
     The ROM  108  for storing system programs and the RAM  110  for saving various data are connected to the input-output bus  104 . Moreover, the random number generating circuit  112 , the communication interface circuit  111 , the display controller  140 , the hopper driving circuit  124 , the speaker driving circuit  122 , and the display driving circuit  128  are connected to the input-output bus  104 . 
     Taking acceptance of a starting operation of a game by the start switch  27  as a trigger, the CPU  106  reads out a game execution program and executes a slot game. The game execution program is the program for executing slot game on the display  16  by way of the display controller  140 . 
     Specifically, the game execution program is programmed to execute a slot game by scrolling the symbols in the each display regions q 1   a  to q 3   e  (see  FIG. 6 ), then stopping the symbols (rearranging the arranged symbols), and providing an award according to the stopped symbols and points attributed to those symbols. 
     The communication interface circuit  111  is connected to a hall server, for example, and transmits data such as a play history executed by the slot machine  10  to the hall server. Meanwhile, the communication interface circuit  111  receives various data transmitted from the hall server. 
     The random number generating circuit  112  generates a random number for determining whether or not it is appropriate to grant the winning in the slot game executed on the display  16 . 
     The display driving circuit  128  performs control to display an amount of provision in the provision amount display region  48  defined in the lower left region of the display  16 . 
     The speaker driving circuit  122  outputs voice data to the speaker  29 . Specifically, the CPU  106  reads the voice data stored in the ROM  108  and transmits the voice data to the speaker driving circuit  122  through the input-output bus  104 . In this way, predetermined sound effects are outputted from the speaker  29 . 
     The hopper driving circuit  124  outputs a provision signal to the hopper  44  when a cash-out becomes effective. Specifically, when a cash-out signal is inputted from the cash-out switch  23 , the CPU  106  outputs a driving signal to the hopper driving circuit  124  through the input-output bus  104 . Accordingly, the hopper  44  provides the medals corresponding to the remaining amount of credits at that point stored in a given memory region of the RAM  110 . 
     The display controller  140  performs display control to execute the slot game on the display  16 . Specifically, the CPU  106  generates an image display instruction signal corresponding to a state of the slot game and an outcome of the slot game. Then, the CPU  106  outputs the image display instruction signal to the display controller  140  through the input-output bus  104 . When the image display instruction signal outputted from the CPU  106  is inputted to the display controller  140 , the display controller  140  generates a driving signal for driving the display  16  based on the image display instruction signal and outputs the generated driving signal to the display  16 . In this way, a predetermined image is displayed on the display  16 . 
     Here, this display  16  includes a liquid crystal display device, and is adapted to display the symbols by varying and arranging the symbols in the display regions q 1   a  to q 3   e  based on the image display instruction signal transmitted from the CPU  106  through the input-output bus  104 , and to change the targeted-symbol display regions among the display regions q 1   a  to q 3   e  on the display  16  based on the amount of bet made by the player. In other words, the display  16  is adapted to display the targeted-symbol display regions brightly and the regions other than the targeted-symbol display regions darkly. 
     Next, operations of the slot machine  10  according to the embodiment of the present invention will be described with reference to flowcharts shown in  FIG. 7 ,  FIG. 8 , and  FIG. 9 .  FIG. 7  is a flowchart showing procedures of an execution process of the slot game executed by the slot machine  10  according to the embodiment. 
     First, the CPU  106  shown in  FIG. 5  receives a bet of medals or credits by the player (step S 11 ). Specifically, when the player makes a bet in a desired amount of credits by pressing the BET switch  25  or inserts the desired amount of medals into the medal insertion slot  21 , this amount is inputted as the bet amount. 
     When the bet is made by pressing the BET switch  25 , the CPU  106  subtracts the credits equivalent to the bet amount from current credits (step S 12 ). For example, if the bet in an amount of “10” credits is made while having the current credits equal to “30”, the remaining credits will become “20” as a result of subtraction. 
     Here, the CPU  106  stores the accepted bet amount in the RAM  110  or the like. 
     The CPU  106  determines whether or not the start switch  27  is turned on (step S 13 ). When the start switch  27  is turned on (YES in step S 13 ), the CPU performs a stopped symbol determination process (step S 14 ). In this process, the symbols to be displayed on the each display regions q 1   a  to q 3   e  are determined based on random numbers obtained from the random number generating circuit  112 . 
     The CPU  106  executes an image effect control process (step S 15 ). In this process, the stopped symbols determined in step S 14  are displayed on the each display regions q 1   a  to q 3   e . The image effect control process will be described later in detail. 
     Subsequently, the CPU  106  performs a provision process based on the symbols displayed in the each display regions q 1   a  to q 3   e  (step S 16 ). The provision process will be described later in detail. 
     Next, the image effect control process shown in step S 15  of  FIG. 7  will be described with reference to  FIG. 8 . 
     First, the CPU  106  outputs an instruction signal to start scroll display of the symbols to the display controller  140 . Along with the input of this instruction signal, the display controller  140  starts scrolling the symbols in the each display regions q 1   a  to q 3   e  on the display  16 . Here, among the each display regions q 1   a  to q 3   e , the targeted-symbol display regions are displayed brightly while the regions other than the targeted-symbol display regions are displayed darkly (step S 31 ). 
     Specifically, in the case of a small bet amount such as 10 medals, for example, the targeted-symbol display regions are defined as three columns on the left covering the regions q 1   a  to q 3   a , q 1   b  to q 3   b , and q 1   c  to q 3   c  as shown in  FIG. 1A . In the case of a medium bet amount such as 20 medals, for example, the targeted-symbol display regions are defined as four columns on the left covering the regions q 1   a  to q 3   a , q 1   b  to q 3   b , q 1   c  to q 3   c , and q 1   d  to q 3   d  as shown in  FIG. 2A . In the case of a maximum bet amount such as 30 medals, for example, the targeted-symbol display regions are defined as all the columns (five columns) covering the regions q 1   a  to q 3   a , q 1   b  to q 3   b , and q 1   c  to q 3   c , q 1   d  to q 3   d , and q 1   e  to q 3   e  as shown in  FIG. 3A . In any of these cases, the targeted-symbol display regions are brightly displayed. 
     Here, the CPU  106  is configured to perform the control of the display regions on the display  16  including the liquid crystal display device through the display controller  140  based on the stored bet number. 
     Next, the CPU  106  measures a time lapse from the start of scrolling the symbols (step S 32 ). When a lapse of a predetermined time period (such as 5 seconds) is confirmed (YES in step S 32 ), the CPU  106  sequentially stops the symbols in the each display regions q 1   a  to q 3   e  (step S 33 ). As a consequence, in the case of the bet equivalent to 10 medals or credits, for example, the three columns on the left are displayed as the targeted-symbol display regions q 1   a  to q 3   a , q 1   b  to q 3   b , and q 1   c  to q 3   c  while the two columns on the right are displayed as non-targeted-symbol display regions q 1   d  to q 3   d  and q 1   e  to q 3   e , as shown in  FIG. 1 . The symbols are displayed in the each display regions. 
     Then, this process is terminated. 
     Next, the provision process shown in step S 16  in  FIG. 7  will be described with reference to  FIG. 9 . 
     First, in step S 51 , the award is determined with reference to a winning setting table. For example, when the symbols are rearranged as shown in  FIG. 3A  in a game of the maximum bet amount (equivalent to 30 medals or credits), reference is made to the winning setting table shown in  FIG. 3B . In this case, three dolphin symbols appear in the targeted-symbol display regions. Accordingly, the award equivalent to 15 medals is determined. 
     Subsequently, the CPU  106  provides credits or medals corresponding to the determined winning (step S 51 ). Specifically, when the symbols are rearranged as shown in  FIG. 3A  in the game of the maximum bet amount, 15 medals or credits is provided. In this way, the provision process is carried out. 
     Here, when the symbols are rearranged as shown in  FIG. 2A  in the game of the medium bet amount (20 medals or credits), for example, reference is made to the winning setting table shown in  FIG. 2B . In this case, there are not three or more symbols of the same type appearing in the targeted-symbol display regions. Accordingly, an award equivalent to 0 medals is determined. Meanwhile, when the symbols are rearranged as shown in  FIG. 1A  in the game of the small bet amount (10 medals or credits), for example, reference is made to the winning setting table shown in  FIG. 1B . In this case, there are not three or more symbols of the same type appearing in the targeted-symbol display regions. Accordingly, an award equivalent to 0 medals is determined. 
     In this way, according to the slot machine  10  of this embodiment, the number of columns of the targeted-symbol display regions among the display regions q 1   a  to q 3   e  on the display  16  is increased along the increase in the amount of bet to be made. In addition, more advantageous symbols (high class symbols) are positioned in columns toward the right-most side which are activated along the increase in the bet amount. 
     Therefore, this slot machine has an effect to offer more advantages along the increase in the amount of bet to be made. Accordingly, the slot machine can attract the player&#39;s interest in betting actions and thereby to improve entertainment properties. 
     Specifically, the player can discern the symbols in the regions other than the targeted-symbol display regions. Therefore, if the symbols are rearranged as shown in  FIG. 1A , for example, there are not three or more symbols of the same type appearing in the targeted-symbol display regions and no award is provided as a consequence in this case, however, the player would notice that this game might have provided an award equivalent to 15 medals attributable to three dolphin symbols if the player had made a bet in the maximum bet amount. In this way, it is possible to attract the interest of the player in betting action by urging the player to make a larger bet thereafter. 
     Next, a modified example of the slot machine  10  according to the above-described embodiment will be described. As shown in  FIG. 10 , the slot machine  10  according to the modified example is configured to drive rotatable reels  53   a  to  53   e  provided with the symbols on circumferential surfaces thereof by using a motor driving circuit  51  and to vary and rearrange the symbols while detecting positions with a reel position detection circuit  52 . As described in the embodiment, as for the rotatable reels  53   a  to  53   e , number of high class symbols increases for the reel positioned to the right. 
     Meanwhile, the display  16  has a configuration as shown in  FIG. 11 and 12  so as to allow the targeted-symbol display regions to occupy three columns on the left in the case of the small bet amount as shown in  FIG. 1A , four columns on the left in the case of the medium bet amount as shown in  FIG. 2A , and all the columns (five columns) in the case of the maximum bet amount as shown in  FIG. 3A . 
     Specifically,  FIG. 11  is a perspective view showing appearance of the display  16  viewed from a back face side and  FIG. 12  is an exploded perspective view showing the configuration of the display  16  shown in  FIG. 11 . Note that some constituents shown in  FIG. 11  are omitted in  FIG. 12 . 
     As shown in  FIGS. 11 and 12 , the display  16  includes a display plate  73 , a transparent liquid crystal panel  74 , a light guiding plate  75 , and a reflection film  76 , which are disposed from the front face side of the slot machine  10  in this order. Moreover, a rotatable reel device  53  including reels  53   a  to  53   e  is disposed on the back face side of the display  16 . 
     Moreover, the display  16  includes fluorescent lamps  77   a  and  77   b , and lamp holders  79   a  to  79   d  for supporting the fluorescent lamps  77   a  and  77   b . The fluorescent lamps  77   a  and  77   b , and the lamp holders  79   a  to  79   d  are located above and below the light guiding plate  75 . 
     The display plate  73  is the component to define an image display region  61  for displaying various effect images, which is made of a transparent member. A region located on the front face side of the each reels  53   a  to  53   e  (a symbol display region  62 ) on image display region is usually set to a transparent state for display so that the symbols drawn on the each reels  53   a  to  53   e  are visually recognizable through the symbol display region  62 . Meanwhile, a region within the image display region  61  excluding the symbol display region  62  is set to a state of image display and various images are displayed therein. 
     The transparent liquid crystal panel  74  is formed by sealing liquid crystal into a clearance between a transparent base plate such as a glass plate provided with a thin film transistor layer and another transparent base plate opposed thereto. This transparent liquid crystal panel  74  is configured to be transparent in a normal state, i.e. a state of not performing liquid crystal display. Therefore, the transparent liquid crystal panel  74  performs transparent display when the liquid crystal is not driven, whereby the light passing through the transparent liquid crystal panel  74  to a display surface side is visible to outside. This state represents the above-mentioned state of transparent display. Meanwhile, this transparent liquid crystal panel  74  can also partially perform semi-transparent display by driving a certain part of liquid crystal. 
     Here, when the slot game in the maximum bet amount is executed, the symbol display region  62  located substantially in the center of the transparent liquid crystal display  74  is entirely not driven so as to allow the player to visually check all the reels  53   a  to  53   e.    
     In the case of the small bet amount, a portion of the display region corresponding to three columns on the left is set to a transparent state to achieve bright display while a portion of the display region corresponding to two columns on the right is set to a semi-transparent state to achieve dark display. Meanwhile, in the case of the medium bet amount, a portion of the display region corresponding to four columns on the left is set to the transparent state to achieve bright display while a portion of the display region corresponding to one column on the right is set to a semi-transparent state to achieve dark display. 
     Alternatively, it is also possible to drive the symbol display region  62  according to effects using images to display various images as appropriate. 
     The light guiding plate  75  is configured to guide light from the fluorescent lamps  77   a  and  77   b  to the transparent liquid crystal panel  74 , and thereby to illuminate the transparent liquid crystal panel  74 . To be more precise, the light guiding plate  75  is a transparent member made of acrylic resin having a thickness of about 2 cm, which has a light guiding function. 
     The reflection film  76  is typically formed of depositing a silver film either on a white polyester film or an aluminum thin film, and is configured to reflect the light guided into the light guiding plate  75  toward a front face side of the light guiding plate  75 . This reflection film  76  includes a reflective region  76 A and a non-reflective region  76 B. The non-reflective region  76 B is made of a transparent material and is provided in a region corresponding to the reels  53   a  to  53   e.    
     The fluorescent lamps  77   a  and  77   b  are disposed along an upper end and a lower end of the light guiding plate  75 , and ends of the lamps  77   a  and  77   b  are supported by the lamp holders  79   a  to  79   d . The light from these lamps  77   a  and  77   b  is reflected by the reflective region  76 A of the reflection film  76  and thereby illuminates the transparent liquid crystal panel  74 . 
     Meanwhile, lamps  78   a  to  78   e  made of light emitting diodes (LEDs) or the like are provided on upper parts and lower parts of the respective reels  53   a  to  53   e , on the back side of the reflection film  76 . The lamps  78   a  to  78   e  are disposed so as to emit light toward the respective reels  53   a  to  53   e . The light emitted from these lamps  78   a  to  78   e  is reflected on surfaces of the respective reels  53   a  to  53   e . Then, part of the light emitted from the lamps  78   a  to  78   e  reflected by the surfaces of the reels  53   a  to  53   e  is incident on the non-reflective region  76 B to illuminate the transparent liquid crystal panel  74 . 
     In essence, when the region (the symbol display region  62 ) of the transparent liquid crystal panel  74  located at the front face side of all the reels  53   a  to  53   e  is set to transparent state, and when all the lamps  78   a  to  78   e  provided on the upper parts and the lower parts of the reels  53   a  to  53   e  are turned on, the symbol display region  62  is set to the state of transparent display, so that the player can see all the reels  53   a  to  53   e  provided at the back face side of the transparent liquid crystal panel  74   
     Although the embodiment has been described herein above, the embodiment is only showing a specific example, and does not particularly limit the present invention. Accordingly, the specific configuration of each means or the like can be modified in design appropriately. In addition, the effects described in the embodiment are only listing the most preferable effects that arise from the present invention. For this reason, the effects produced by the present invention are not limited to those described in the embodiment. 
     In addition, in the foregoing detailed description, the characteristic portions of the present invention have been mainly described in order to make the present invention easily understandable. The present invention is not limited to the embodiment described above in detail, and can be applied to other embodiments, and its applicable range is wide. Moreover, the terms and the terminology used in the present specification are used for the purpose of precisely explaining the present invention, and not used for the purpose of limiting interpretations of the present invention. Further, it should be easy for those skilled in the art to contemplate other configurations, systems, methods, etc., which are included in the concept of the present invention, from the concept of the present invention described in the present specification. For this reason, the description of the appended claims must be construed as containing equivalent configurations within a range not departing from the technical ideas of the present invention. Moreover, the abstract aims to allow the United States Patent and Trademark Office, general public office, and engineers who are not familiar with a patent, legal terms, and technical terms, and who pertain to the technical field of the present invention, to quickly judge the technical content and essence of the present application with a simple study. Accordingly, the abstract is not intended to limit the scope of the invention that should be assessed from the description of the appended claims. Furthermore, it is desirable that the present invention be interpreted by fully taking already-disclosed literatures and the like into consideration in order to fully understand the object of the present invention and unique effects of the present invention. 
     The foregoing detailed description includes the processing executed by a computer. The above description and expressions are described in order for those skilled in the art to understand the present invention in the most efficient way. In this specification, each step used for deriving one result should be understood as processing without self-contradiction. Moreover, in each step, transmission, reception, storage, etc., of an electric or magnetic signal is performed. Expressions such as bit, value, symbol, letter, term, number, and the like are used to express such a signal in the processing in each step, but it should be noted that these are simply used to make the explanation easy. In addition, the processing in each step is sometimes described in an expression in common with human activities, but the processing described in this specification is primarily executed by various types of devices. Furthermore, other configurations required for executing each step is obvious from the foregoing description.