Patent Publication Number: US-7901087-B2

Title: Projector and control method thereof

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
     This application is a Division of and is based upon and claims the benefit of priority under 35 U.S.C. §120 for U.S. Ser. No. 12/035,835, filed Feb. 22, 2008, and claims the benefit of priority under 35 U.S.C. §119 from Japanese Patent Application No. 2007-060435, JP 2007-060437, and JP 2007-060439, these filed with the Japan Patent Office on Mar. 9, 2007, the entire contents of which being incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a projector and a control method thereof, and particularly to a projector and a control method thereof that properly assist in an operation of replacing a lamp in a projector, whereby proper driving control for the lamp can be realized. 
     2. Description of the Related Art 
     Recently, with the development of video display technology, a projector applicable to a field of so-called digital cinema, that is, a projector usable for a purpose of screening a movie in a movie theater has appeared (see Japanese Patent Laid-Open No. Hei 5-260423, for example). 
     As such a projector, there is a projector having a power supply (hereinafter referred to as a lamp power supply) that can drive lamps of a plurality of kinds of lamp sizes. A lamp size in this case refers to an input rating such as a minimum wattage, a maximum wattage and the like of the lamp. 
     The life of the lamp is not infinite but finite. It is therefore necessary to manage the use time or the like of the lamp properly, and replace the lamp at an appropriate time. This is because some lamps may demand replacement a maximum of about eight times a year. 
     In this case, in the past, a lamp replacing worker manually sets the lamp power supply according to the lamp size of a lamp to be substituted. Alternatively, the lamp replacing worker selects a lamp of a predetermined lamp size according to the setting of the lamp power supply. 
     SUMMARY OF THE INVENTION 
     However, in this case, the lamp replacing worker may make a wrong setting through an operation mistake, or select a wrong lamp. In such a case, there is a danger of a current exceeding a rated current flowing through the lamp and thus a burst failure or the like occurring. 
     A wrong lamp in this case refers to a lamp of a lamp size that does not match the setting of the lamp power supply unit. A reason that the lamp size does not match the setting of the lamp power supply unit may be that the selection of the lamp size itself is wrong, or that although the selection of the lamp size itself is correct, a lamp of a lamp size different from the selected lamp size is prepared by mistake because lamps are generally identical or similar in shape. 
     In addition, when a lamp of a lamp size that does not perfectly match the set range of the lamp power supply unit prepared in advance is loaded into the existing projector, even use of the lamp is not possible in the first place. 
     The present invention has been made in view of such a situation. It is desirable to assist properly in an operation of replacing a lamp in a projector, and thereby realize proper driving control for the lamp. 
     According to an embodiment of the present invention, there is provided a projector that can be loaded with lamps of a plurality of kinds, each of a plurality of the lamps loadable into the projector being given a lamp serial code formed by arranging lamp information including at least a minimum wattage and a maximum wattage of the lamp and a check sum in predetermined order. The projector includes: a lamp power supply for driving the lamp loaded in the projector, the lamp power supply being provided in advance with a plurality of mode ranges each as a range from a minimum wattage to a maximum wattage of output of the lamp power supply, and one predetermined mode range of the plurality of mode ranges being freely set in the lamp power supply; and a control circuit for controlling the lamp power supply. The control circuit sets a range from the minimum wattage to the maximum wattage included in the lamp serial code given to the lamp loaded in the projector as a code range, and compares the code range with the mode range set in the lamp power supply. The control circuit determines a range not exceeding the maximum wattage included in the lamp serial code as a lamp driving controlling range within which the driving of the lamp power supply is controlled on a basis of a result of comparison of the code range with the mode range. The control circuit controls the driving of the lamp power supply within the determined lamp driving controlling range. 
     The control circuit determines a range in which the code range and the mode range overlap each other as the lamp driving controlling range. 
     A control method of a projector according to an embodiment of the present invention is a method corresponding to a control method of the control circuit in the projector according to the above-described embodiment of the present invention. 
     In the projector according to the above-described embodiment of the present invention and the control method of the projector, the projector can be loaded with lamps of a plurality of kinds of lamp sizes, and each of a plurality of the lamps loadable into the projector is given a lamp serial code formed by arranging lamp information including at least a minimum wattage and a maximum wattage of the lamp and a check sum in predetermined order. The projector includes: a lamp power supply for driving the lamp loaded in the projector, the lamp power supply being provided in advance with a plurality of mode ranges each as a range from a minimum wattage to a maximum wattage of output of the lamp power supply, and one predetermined mode range of the plurality of mode ranges being freely set in the lamp power supply; and a control circuit for controlling the lamp power supply. In the projector, the following control is performed. A range from the minimum wattage to the maximum wattage included in the lamp serial code given to the lamp loaded in the projector is set as a code range, and the code range is compared with the mode range set in the lamp power supply. On a basis of a result of the comparison, a range not exceeding the maximum wattage included in the lamp serial code is determined as a lamp driving controlling range within which the driving of the lamp power supply is controlled. As a result, the driving of the lamp power supply is controlled within the determined lamp driving controlling range. 
     As described above, according to the embodiment of the present invention, it is possible to control the driving of the lamp of the projector. In particular, it is possible to assist properly in an operation of replacing a lamp in a projector, and thereby realize proper driving control for the lamp. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram showing an example of configuration of an information processing system to which an embodiment of the present invention is applied; 
         FIG. 2  is a diagram showing an example of configuration of a projector to which the embodiment of the present invention is applied, the projector being one constituent element of the information processing system of  FIG. 1 ; 
         FIG. 3  is a diagram showing an example of external structure of a lamp loaded into the projector of  FIG. 2 ; 
         FIG. 4  is a diagram showing an example of lamp modes that can be set in a lamp power supply of the projector of  FIG. 2 ; 
         FIG. 5  is a flowchart of assistance in explaining an example of a projector lamp replacement time process among processes performed by the projector of  FIG. 2 ; 
         FIG. 6  is a diagram showing an example of a GUI image including a lamp timer reset button; 
         FIG. 7  is a diagram showing an example of structure of a lamp serial code; 
         FIG. 8  is a diagram showing an example of a GUI image including a lamp serial code input screen displayed by pop-up display; 
         FIG. 9  is a diagram of assistance in explaining a method of determining a lamp driving controlling range to which the embodiment of the present invention is applied; 
         FIG. 10  is a flowchart of assistance in explaining an example of a lamp timer management process among the processes performed by the projector of  FIG. 2 ; 
         FIG. 11  is a diagram showing an example of a GUI image showing the use time of the lamp loaded in the projector of  FIG. 2 ; and 
         FIG. 12  is a flowchart of assistance in explaining a process of generating a lamp serial code for a lamp to be loaded in the projector of  FIG. 2 , that is, an example of a lamp serial code generating process. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Preferred embodiments of the present invention will hereinafter be described. Correspondences between constitutional requirements of the present invention and embodiments described in the detailed description of the invention are illustrated as follows. This description is to confirm that embodiments supporting the present invention are described in the detailed description of the invention. Therefore, even when there is an embodiment described in the detailed description of the invention but not described here as corresponding to a constitutional requirement, it does not signify that the embodiment does not correspond to the constitutional requirement. Conversely, even when an embodiment is described here as corresponding to a constitutional requirement, it does not signify that the embodiment does not correspond to constitutional requirements other than that constitutional requirement. 
     Further, this description does not signify that inventions corresponding to concrete examples described in the detailed description of the invention are all described in the claims. In other words, this description does not negate presence of inventions corresponding to concrete examples described in the detailed description of the invention but not described in the claims of the present application, that is, presence of inventions to be presented in a divisional application or to be added by amendments in the future. 
     A projector according to an embodiment of the present invention is a projector (a projector  33  in  FIG. 2  that can be installed in movie theaters  11 A to  11 N in  FIG. 1 , for example) that can be loaded with lamps (a lamp  58  having the shape of  FIG. 3 , for example) of a plurality of kinds of lamp sizes, each of a plurality of the lamps loadable into the projector being given a lamp serial code (a lamp serial code having the structure of  FIG. 7 , for example) formed by arranging lamp information including at least a minimum wattage and a maximum wattage of the lamp and a check sum in predetermined order, the projector including: a lamp power supply (for example a lamp power supply unit  56  having a setting SW  73  in  FIG. 2  as a switch for setting one predetermined mode of lamp modes A to D in  FIG. 4 ) for driving the lamp loaded in the projector, the lamp power supply being provided in advance with a plurality of mode ranges each as a range from a minimum wattage to a maximum wattage of output of the lamp power supply (for example four mode ranges defined by respective maximum output wattages and minimum output wattages of lamp modes A to D in  FIG. 4 ), and one predetermined mode range of the plurality of mode ranges being freely set in the lamp power supply; and a control circuit (for example a CPU  51  in  FIG. 2 ) for controlling the lamp power supply; wherein the control circuit sets a range from the minimum wattage to the maximum wattage included in the lamp serial code given to the lamp loaded in the projector as a code range, and compares the code range with the mode range set in the lamp power supply (for example step S 7  in  FIG. 5 ), the control circuit determines a range not exceeding the maximum wattage included in the lamp serial code as a lamp driving controlling range within which the driving of the lamp power supply is controlled on a basis of a result of comparison of the code range with the mode range (for example step S 10  after a result of determination in step S 8  is YES in  FIG. 5 ), and the control circuit controls the driving of the lamp power supply within the determined lamp driving controlling range. 
     The control circuit determines a range in which the code range and the mode range overlap each other as the lamp driving controlling range (see  FIG. 9 , for example). 
     A controlling method of a projector according to an embodiment of the present invention is a method (for example a method corresponding to a projector lamp replacing time process of  FIG. 5  among processes performed by a CPU  51  in the projector  33  of  FIG. 2 ) corresponding to a controlling method of the control circuit in the projector according to the above-described embodiment of the present invention. 
     Preferred embodiments of the present invention will hereinafter be described with reference to the drawings. 
       FIG. 1  shows an example of configuration of an information processing system to which the present invention is applied, the information processing system being applied to a field of digital cinema. 
     The information processing system in the example of  FIG. 1  is formed by interconnecting various devices (to be described later in detail) installed in movie theaters  11 A to  11 N and a maintenance server  12  via a predetermined network such as the Internet or the like. The maintenance server  12  in this case refers to for example a device used by a provider of, as a service, maintenance of the various devices installed in the movie theaters  11 A to  11 N. 
     The movie theater  11 A includes a plurality of screening places  22   a  to  22   n  to be able to screen a plurality of movies in parallel. For centralized management of the plurality of screening places  22   a  to  22   n , a Theater Management device  21  (hereinafter referred to as a TM device  21 ) is installed in the movie theater  11 A. 
     The screening place  22   a  includes a Screen Management device  31   a  (hereinafter referred to as an SM device  31   a ) to a screen  34   a.    
     Similarly, the screening place  22   n  includes an SM device  31   n  to a screen  34   n . Each screening place  22   k  (k is an arbitrary lower-case letter of the alphabet) not shown in the figure other than the screening place  22   a  and the screening place  22   n  includes an SM device  31   k  to a screen  34   k.    
     Incidentally, hereinafter, when the screening places  22   a  to  22   n  do not need to be individually differentiated from each other, the screening places  22   a  to  22   n  will be collectively referred to simply as a screening place  22 . In addition, hereinafter, when the screening place  22   k  is referred to simply as the screening place  22 , the SM device  31   k  to the screen  34   k  will also be referred to as the SM device  31  to the screen  34 , respectively. 
     The SM device  31  is a device that performs centralized management of the screening place  22 . The SM device  31  controls other devices within the screening place  22 , that is, a material server  32 , a projector  33  and the like. In addition, the SM device  31  communicates with the TM device  21  to send and receive various information to and from the TM device  21  as necessary. 
     The material server  32  provides digital data of a movie (material) to be screened in the screening place  22  to the projector  33 . 
     The projector  33  projects an image corresponding to the digital data provided from the material server  32  onto the screen  34 . Thereby the movie is screened on the screen  34 . 
     Though not shown in the figure, the other movie theaters  11 B to  11 N similarly have one or more screening places  22 . Each screening place  22  is provided with an SM device  31  to a screen  34 . 
     As described above, the information processing system of  FIG. 1  is applied to the field of digital cinema. In the field of digital cinema, a standard referred to as DCI Spec is defined by an organization referred to as DCI (Digital Cinema Initiatives). The standard specifies that “white peak luminance at the center of a screen be 48 cd/m 2  (14 ft-L) as an image parameter to be referred to”. At 14 ft-L=48 cd/m 2 , a brightness of about 48 candles per square meter may be demanded at the center of the screen  34 . In other words, the brightness (illuminance) of the image projected on the screen  34  may need to be maintained at a constant level at all times. 
     On the other hand, the screen  34  is widely varied in size according to the capacity of the screening place  22  or the like. 
     Thus, according to the size of the screen  34  onto which to perform projection, an optimum lamp that can meet DCI Spec, for example a xenon lamp, may need to be used as a light source of each projector  33 . 
     In addition, as for the angle of view of movies, there are various sizes, including for example a “standard size” with an aspect ratio of 1:1.33, a “Vista size (a European standard)” with an aspect ratio of 1:1.66, a “Vista size (an American standard)” with an aspect ratio of 1:1.85, and a “CinemaScope size (registered trademark)” with an aspect ratio of 1:2.35. Thus, a change may need to be made from one predetermined angle of view to another angle of view among the various angles of view in the same screening place  22 , that is, on the same screen  34 . In such a case, the zoom magnification of a lens of the projector  33  may need to be changed. According to this change, the power of the lamp (input watts) may need to be changed so as to maintain the brightness (illuminance) of the image on the screen  34  at a constant level, as described above. Consequently, a light quantity gain of the lamp may need to be secured for a fixed quantity. Thus, it may be necessary to use a lamp whose minimum wattage and maximum wattage or the like as an input rating (such an input rating will hereinafter be referred to also as lamp size) can accommodate the change, and to make an appropriate setting on a side driving the lamp. 
     The lamp has a life. It may therefore be necessary to manage the use time or the like of the lamp appropriately, and to replace the lamp at appropriate periods. This is because some lamps may need to be replaced a maximum of about eight times a year. 
     Further, the lamp is inserted into a predetermined lamphouse (for example a lamphouse  57  in  FIG. 2  in the present embodiment). Therefore the shape itself of lamps is identical or similar to secure functions (for example the shape of  FIG. 3  is adopted in the present embodiment). However, there are no clear specifications for lamp size, so that lamps of various lamp sizes may be distributed on the market. When the movie theaters  11 A to  11 N in  FIG. 1  are scattered in places distant from each other, in particular, lamps made by lamp manufacturers (manufacturing makers) in respective areas are often used. In such a case, a possibility of lamps of different lamp sizes being distributed on the market in the different areas is further increased. Hence, even when the projectors  33  in the movie theaters  11 A to  11 N project an image onto the screens  34  of a same size, lamps of different lamp sizes may be used as lamps loaded in the projectors  33 . 
     Thus, there is a situation specific to the field of digital cinema regarding lamps for projectors in the field of digital cinema. As a result, various problems as described in the following occur in a movie theater using an existing projector. 
     For example, there is an existing projector having a power supply (hereinafter referred to as a lamp power supply unit) capable of driving lamps of a plurality of kinds of lamp sizes. In this case, in the past, a lamp replacing worker manually sets the lamp power supply unit according to the lamp size of a lamp with which to perform replacement. Alternatively, the lamp replacing worker selects a lamp of a predetermined lamp size according to the setting of the lamp power supply unit. In this case, the lamp replacing worker may make a wrong setting through an operation mistake, or select a wrong lamp. In such a case, there is a danger of a current exceeding a rated current flowing through the lamp and thus a burst failure or the like occurring. A wrong lamp in this case refers to a lamp of a lamp size that does not match the setting of the lamp power supply unit. A reason that the lamp size does not match the setting of the lamp power supply unit may be that the selection of the lamp size itself is wrong, or that although the selection of the lamp size itself is correct, a lamp of a lamp size different from the selected lamp size is prepared by mistake because lamps are generally identical or similar in shape and the lamp size may not be determined by only a visual check. When a lamp of a lamp size that does not perfectly match the set range of the lamp power supply unit prepared in advance is loaded into the existing projector, even use of the lamp is impossible in the first place. Such a problem will hereinafter be referred to as a lamp size problem. 
     In addition, for example, because it may be necessary to manage the use time or the like of the lamp appropriately, as described above, a timer (hereinafter referred to as a lamp timer) for measuring the lamp use time is provided also in the existing projector. In the past, however, the lamp timer can be reset at any time by an operator or the like in the screening place  22 . Therefore, even when the life of the lamp has ended within a guaranteed time of the lamp, there is no means for officially proving that the life of the lamp has ended within the guaranteed time of the lamp. That is, when the life of the lamp has ended within the guaranteed time of the lamp, a new lamp can be offered free of charge, with a special agreement concluded for free replacement of the lamp or the like. However, there is no means for determining whether or not to implement the agreement. In addition, a projector capable of being loaded with a plurality of kinds of lamp sizes includes a part whose periodic replacement time differs depending on light quantity (lamp size). When determining a replacement time of such a part, a part replacing person (a serviceman) has no means for checking history information indicating what lamp has been used. Such a problem will hereinafter be referred to as a lamp use history problem. 
     In addition, for example, the existing lamp timer can be reset at any time by an operator or the like in the screening place  22 , as described above. There is thus a possibility that the lamp use time is not strictly managed. Further, as described above, even a lamp not certified for the existing projector can be readily used in the projector. The lamp is often inappropriate in terms of adaptability (for example cooling, driving current, mechanical size, and the like) to the projector. As a result, there is a danger of the projector failing, or the lamp bursting, for example. Such a problem will hereinafter be referred to as a lamp management problem. 
     In addition, in the field of digital cinema, each of the movie theaters  11 A to  11 N desires to purchase lamps from a plurality of lamp manufacturers in order to lower maintenance cost. Thus, as described above, lamps of various lamp sizes are mixed in the market. On the other hand, when switching is performed between the “CinemaScope size” and the “Vista size”, for example, the brightness (illuminance) of images projected on the screen  34  may need to be maintained at a constant level at all times, as described above. In this case, to secure a constant brightness, the light quantity gain of the lamp may need to be maintained at 1.6. In the past, however, no provision can be made in some cases with the set range of the lamp power supply unit prepared in advance. Such a problem will hereinafter be referred to as a lamp gain problem. 
     In addition, for example, In the past, a recommended replacement time differs depending on the lamp loaded into a projector having a lamp power supply unit capable of driving lamps of a plurality of kinds of lamp sizes. Therefore an operator or the like in the screening place  22  independently manages lamp replacement timing while comparing the recommended replacement time of the lamp with the lamp timer. As a result, the management is complex, and there is a danger of a screening trouble or the like occurring due to a mistake in the management. Such a problem will hereinafter be referred to as a lamp replacement time problem. 
     In the information processing system of  FIG. 1  to which an embodiment of the present invention is applied, the projector  33  that can solve the various problems described above is installed in each screening place  22 . That is, the projector  33  is one embodiment of a projector to which the present invention is applied. An example of configuration of the projector  33  is shown in  FIG. 2 . 
     In the projector  33  as the example of  FIG. 2 , a CPU (Central Processing Unit)  51  performs various processes according to a program or the like recorded in a memory  52 . The memory  52  also stores data and the like necessary for the CPU  51  to perform the various processes. 
     The CPU  51  is also connected with an input-output unit  53 , an I/O unit  54 , and an input-output interface  55 . 
     The input-output unit  53  is for example formed by a touch panel or the like. The input-output unit  53  includes an input unit  71  for allowing a user (an operator or the like in the screening place  22  in  FIG. 1 ) to perform various operations, and a display unit  72  formed by a display or the like for displaying the descriptions of the operations and the like. 
     The I/O unit  54  relays various information sent and received between the CPU  51  and a lamp power supply unit  56 . Incidentally, a concrete example of the relayed various information will be described later in the description of step S 10  in  FIG. 5 . 
     The lamp power supply unit  56  is a power supply capable of driving lamps  58  of a plurality of kinds of lamp sizes. That is, the lamp power supply unit  56  provides an appropriate driving power to a lamp  58  loaded in a lamphouse  57  under control of the CPU  51  via the I/O unit  54 . 
     The lamp  58  in the present embodiment for example has a shape shown in  FIG. 3 . That is, in the present embodiment, lamps having a capability (replacement capability) of being loaded into the projector  33  as lamp  58  each have the same shape as the shape of  FIG. 3 . However, such lamps can have various lamp sizes. It is therefore difficult for an operator or the like to determine the lamp size of a lamp to be substituted as lamp  58  by merely visually checking the shape (the shape of  FIG. 3 ) of the lamp. As a result, there is a possibility of occurrence of various problems such as the above-described lamp size problem and the like. Accordingly, to avoid occurrence of these problems, the projector  33  performs a lamp replacement time process of  FIG. 5  to be described later. 
     However, the shape of the lamp  58  is not limited to the example of  FIG. 3 , and it suffices for the lamp  58  to have such a shape as to be loadable into the lamphouse  57 . In other words, the shape of the lamp  58  depends on the structure of the lamphouse  57 . That is, the lamphouse  57  in the present embodiment happens to have the structure into which the lamp  58  of the shape of  FIG. 3  can be loaded. 
     Thus, the projector  33  has a possibility of being loaded with lamps of various lamp sizes as lamp  58 . The lamp power supply unit  56  is accordingly configured such that a plurality of modes (hereinafter referred to as lamp modes) can be set in the lamp power supply unit  56  as an output rating such as a maximum output wattage, a minimum output wattage, and a maximum current. Specifically, in the present embodiment, for example, each of four lamp modes A to D as shown in  FIG. 4  can be set in the lamp power supply unit  56 . As a switch for setting one of the lamp modes A to D, in the present embodiment, for example, a setting SW  73  shown in  FIG. 2  is provided for the lamp power supply unit  56 . Specifically, for example, when the lamp mode A is set by the setting SW  73 , the lamp power supply unit  56  performs driving within a range defined by a maximum output wattage of 4.6 kW, a minimum output wattage of 2.0 kW, and a maximum current of 167 A, according to  FIG. 4 . 
     Incidentally, the rated output range thus defined by the lamp mode, that is, the range from the maximum output wattage to the minimum output wattage will hereinafter be referred to as a mode range. In other words, the mode range can be said to be a range for limiting output with the minimum output wattage as a lowest limit and limiting output with the maximum output wattage as a highest limit, that is, a range for limiting the driving of the lamp power supply unit  56 . Specifically, for example, the mode range of the lamp mode A refers to a range of 2.0 kW to 4.6 kW (see  FIG. 9  to be described later). 
     The input-output interface  55  in  FIG. 2  is connected with a communicating unit  59  and a drive  60 . The communicating unit  59  controls a process of communication with other devices including the external SM device  31  and the material server  32  (see  FIG. 1 ). The form of the communication in this case is not specifically limited, and the communication may be a wire communication or a wireless communication. In addition, the communication may be performed through a direct connection, or may be performed via a network including the Internet. 
     Further, the communicating unit  59  can externally obtain a program by such communication control, and store the program in the memory  52 . 
     When a removable medium  74  such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory or the like is loaded into the drive  60 , the drive  60  drives the removable medium  74  to obtain a program, data or the like recorded on the removable medium  74 . The obtained program or data is transferred to the memory  52  to be stored in the memory  52  as necessary. 
     An example of a process performed when a predetermined lamp is substituted as a lamp  58  (hereinafter referred to as a projector lamp replacement time process) among processes performed by the projector  33  having such a configuration will next be described with reference to a flowchart of  FIG. 5 . 
     Incidentally, the description will be made referring to concrete examples of  FIGS. 6 to 9 . 
     In step S 1 , the CPU  51  determines whether a lamp timer reset button has been pressed. 
     Until the lamp timer reset button is pressed, a process of obtaining a result of determination of NO in the process of step S 1  and performing the process of step S 1  again is repeated. 
     An example of the lamp timer reset button will be described in the following with reference to  FIG. 6 . 
       FIG. 6  shows an example of a GUI (Graphical User Interface) image for performing the setting, management and the like of the projector  33 . In the present embodiment, for example, this GUI image is displayed on the display unit  72 . In the present embodiment, for example, a software button  101  described as “RESET” in the GUI image is assigned the function of the lamp timer reset button. 
     Thus, after a lamp replacing worker substitutes a predetermined lamp as lamp  58 , the lamp replacing worker can press the software button  101  by operating the input unit  71 , or performing an operation of bringing a finger of the lamp replacing worker or the like into contact with the touch panel when the input-output unit  53  is formed by the touch panel, for example. In this case, a result of the determination in the process of step S 1  in  FIG. 5  is YES, and therefore the process proceeds to step S 2 . 
     In step S 2 , the CPU  51  makes pop-up display of a lamp serial code input screen on the display unit  72 . Then, in step S 3 , the CPU  51  determines whether a lamp serial code has been input. 
     The lamp serial code and the lamp serial code input screen will be described in the following with references to  FIG. 7  and  FIG. 8 . 
     The lamp serial code refers to information formed by arranging one or more pieces of lamp information on a predetermined lamp and the like in predetermined order when a lamp manufacturer (manufacturing maker) manufactures the predetermined lamp that can be a lamp  58 . “And the like” is included in the “lamp information . . . and the like” because information other than the lamp information, such as a check sum (“Check sum”/“check sum”) or the like, can be included in the lamp serial code, as will be described later. The lamp information itself is not specifically limited as long as the lamp information is information on the predetermined lamp. For example, information for uniquely identifying the predetermined lamp (ID or the like), management information on the predetermined lamp, and the like can be adopted as the lamp information. 
     Incidentally, a lamp as an object to which the lamp serial code is given will hereinafter be referred to as an object lamp. 
     The lamp serial code is provided together with the object lamp, for example. Specifically, in the present embodiment, for example, the lamp serial code is printed on a paper medium, and the paper medium is packaged and shipped together with the object lamp. 
       FIG. 7  shows an example of structure of the lamp serial code. As shown in  FIG. 7 , the lamp serial code is formed by arranging pieces of text information “Check sum/manufacturer code/max watt/min watt/life hour/lamp serial/check sum”. 
     “Check sum”/“check sum” is information used to determine whether predetermined text information input by a lamp replacing worker as the lamp serial code in the process of step S 3  in  FIG. 5  to be described later is a valid lamp serial code after the object lamp is substituted as the lamp  58  in the projector  33 . 
     Thus, as described above, the lamp serial code may need to be created additionally when the lamp manufacturer (manufacturing maker) manufactures the object lamp. “Check sum”/“check sum” is calculated when the lamp serial code is created. Incidentally, a method of creating the lamp serial code will be described later with reference to  FIG. 12 . 
     “manufacturer code” is one piece of lamp information, and is a code for identifying the lamp manufacturer (manufacturing maker) of the object lamp, or a so-called maker ID. 
     “max watt” is one piece of lamp information, and is information indicating a maximum wattage of the lamp size (input rating) of the object lamp. 
     “min watt” is one piece of lamp information, and is information indicating a minimum wattage of the lamp size (input rating) of the object lamp. 
     “life hour” is one piece of lamp information, and is information indicating the nominal life time of the object lamp. 
     “lamp serial” is one piece of lamp information, and is information making it possible to identify the object lamp uniquely, or a so-called serial number. 
     A GUI image for inputting such a lamp serial code to the projector  33  is the lamp serial code input screen. The pop-up display of an image  102  as shown in  FIG. 8 , for example, is made on the display unit  72 , as shown in the same figure. 
     Accordingly, when a lamp replacing worker mounts the object lamp as lamp  58  in the lamphouse  57 , that is, when the lamp replacing worker replaces the lamp  58  with the object lamp, the lamp replacing worker can input the lamp serial code of the object lamp in a box  111  of the lamp serial code input screen  102 , that is, the box  111  on the right of display “Serial Code”. For this input, the input unit  71  is used in the present embodiment, for example. 
     Meanwhile, in the projector lamp replacement time process of  FIG. 5 , a process of obtaining a result of determination of NO in the process of step S 3  and performing the process of step S 3  again is repeated. 
     When a lamp serial code candidate of the object lamp is input in the box  111  in  FIG. 8 , and a software button  112  described as “CHECK” on the right of the box  111  is pressed, the input is confirmed, and contents input in the box  111  are notified to the CPU  51 . Then, in the projector lamp replacement time process of  FIG. 5 , a result of the determination in the process of step S 3  becomes YES, and the process proceeds to step S 4 . 
     In step S 4 , the CPU  51  performs a Check sum confirmation process. 
     In the above expression, the text information input into the box  111  at the time of the process of step S 3  is expressed as a lamp serial code candidate rather than being expressed directly as a lamp serial code. This expression is made because it may be difficult yet to determine whether the text information input in the box  111  is the valid lamp serial code of the object lamp substituted as the lamp  58  at the time of the process of step S 3 , that is, at the time of the input, including an error in input operation by the lamp replacing worker. 
     Accordingly, the CPU  51  may need to perform a process of checking whether the text information is a valid lamp serial code using a part corresponding to “Check sum”/“check sum” of the text information input in the box  111  as described above. Such a process is the “Check sum confirmation process” in step S 4 . 
     In step S 5 , the CPU  51  determines whether a result of the “Check sum confirmation process” indicates a valid code. 
     When the text information (lamp serial code candidate) input into the box  111  is an invalid code, a result of the determination in step S 5  is NO, and the process proceeds to step S 6 . In step S 6 , the CPU  51  makes an error display on the display unit  72 . The error display in this case for example refers to display of a notification indicating that the text information (lamp serial code candidate) input into the box  111  is an invalid code, a notification accordingly prompting for re-input, and the like. Such error display can be realized by making a display in an area  114  in  FIG. 8 , for example. Thereby the projector lamp replacement time process is ended. 
     When the text information (lamp serial code candidate) input into the box  111  is a valid code, on the other hand, a result of the determination in step S 5  is YES, and the process proceeds to step S 7 . 
     That is, at this point in time, it is determined that the text information (lamp serial code candidate) input into the box  111  is a valid code, and therefore the text information input into the box  111  is treated as the lamp serial code in the following processes. 
     In step S 7 , the CPU  51  compares a range (hereinafter referred to as a code range) from a minimum wattage (min watt) to a maximum wattage (max watt) included in the lamp serial code with a range (that is, a mode range) from a minimum output wattage to a maximum output wattage in a set lamp mode. 
     In step S 8 , the CPU  51  determines whether there is a range where the code range and the mode range overlap each other on the basis of a result of the comparison in step S 7 . 
     When there is no range in which the code range and the mode range overlap each other, a result of the determination in step S 8  is NO, and the process proceeds to step S 9 . In step S 9 , the CPU  51  makes an error display on the display unit  72 . The error display in this case for example refers to display of a notification indicating that it is necessary to re-substitute another appropriate lamp as lamp  58  because the object lamp substituted as lamp  58  cannot be controlled by the lamp power supply unit  56  in a present condition, or it is necessary to change the setting of the lamp mode in the lamp power supply unit  56  when the object lamp is used as it is, a notification accordingly prompting for the substitution or the change, and the like. Such error display can also be realized by making a display in the area  114  in  FIG. 8 , for example. Thereby the projector lamp replacement time process is ended. 
     When there is a range in which the code range and the mode range overlap each other, on the other hand, a result of the determination in step S 8  is YES, and the process proceeds to step S 10 . 
     In step S 10 , the CPU  51  determines the range in which the code range and the mode range overlap each other as a lamp driving controlling range. 
     Specifically, for example, when the lamp mode set at this point in time is the lamp mode A in  FIG. 4 , the mode range is a range of 2.0 kW to 4.2 kW. In addition, for example, when the minimum wattage (min watt) included in the lamp serial code is 1.8 kW and the maximum wattage (max watt) included in the lamp serial code is 3.6 kW, the code range is a range of 1.8 kW to 3.6 kW. In such a case, as shown in  FIG. 9 , the range in which the code range and the mode range overlap each other, that is, a range of 2.0 kW to 3.6 kW is determined as the lamp driving controlling range. 
     The lamp driving controlling range in this case refers to a range of output power given as an instruction command among commands output by the CPU  51  in  FIG. 2  to the lamp power supply unit  56  via the I/O unit  54 . That is, the lamp power supply unit  56  performs driving so as to supply the output power specified by the instruction command from the CPU  51  to the lamp  58 . Hence, a predetermined power within the lamp driving controlling range (2.0 kW to 3.6 kW in the example of  FIG. 9 ) is specified by the instruction command for the output power which command is issued from the CPU  51 . As a result, the lamp power supply unit  56  performs driving within the lamp driving controlling range (2.0 kW to 3.6 kW in the example of  FIG. 9 ). The lamp  58  (the object lamp corresponding to the lamp serial code) is thereby supplied with power within the appropriate range. 
     After the lamp driving controlling range is thus determined in the process of step S 10  in  FIG. 5 , the process proceeds to step S 11 . 
     In step S 11 , the CPU  51  automatically resets the lamp timer T (T=0). Automatically resetting the lamp timer T in this case refers to performing the process on the basis of a decision by the CPU  51  itself without depending on an external instruction from the input unit  71  or the like at the time of the process of step S 11 . “Automatically” in the following basically has the same meaning. 
     Then, in step S 12 , the CPU  51  makes a log setting (recording of the nominal life time T(life) and the like), and starts a lamp timer management process. 
     Thereby the projector lamp replacement time process is ended. 
     Description will be made below of the log setting (recording of the nominal life time T(life) and the like). 
     The log setting refers to including the contents of the lamp serial code input in the process of step S 3  in log history information for the object lamp substituted as the lamp  58  this time and storing the log history information in the memory  52 . Specifically, the contents of “manufacturer code”, “max watt”, “min watt”, “life hour”, and “lamp serial” are included in the log history information. Incidentally, the contents of “life hour” will hereinafter be referred to as the nominal life time T(life). 
     Because the log history information is thus stored in the memory  52 , the CPU  51  can read the log history information from the memory  52  as necessary, display the log history information on the display unit  72 , and provide the log history information to other devices, for example not only the SM device  31  but also the TM device  21  and the maintenance server  12  in  FIG. 1  via the communicating unit  59 . 
     Incidentally, in the present embodiment, for example, the log history information can be displayed in an area  113  or the like of the lamp serial code input screen  102  in  FIG. 8  described above. 
     The information included in the log history information is not specifically limited as long as the information included in the log history information is information related to the object lamp substituted this time as lamp  58 . In the present embodiment, for example, a measured value of the lamp timer T is adopted as other information indicating the lamp use time of the object lamp. 
     A process of sequentially updating the measured value of the lamp timer T is the “lamp timer management process” in step S 12  in  FIG. 5 . An example of the lamp timer management process will be described below with reference to  FIG. 10 . 
     In step S 31 , the CPU  51  determines whether an instruction to end the process is given. 
     Though the determining process in step S 31  itself is not specifically limited, suppose that in the present embodiment, for example, it is determined that an instruction to end the process is given when the process of step S 11  in  FIG. 5  is performed, that is, when the lamp timer T is automatically reset. 
     That is, in the present embodiment, when the lamp timer T is automatically reset, it is determined in step S 31  that an instruction to end the process is given, and the lamp timer management process for the lamp  58  before replacement is ended. Then, step S 12  in  FIG. 5  is carried out, whereby the lamp timer management process for the lamp  58  after the replacement is newly started. 
     Hence, in the present embodiment, unless the lamp timer T is automatically reset, a result of the determination in step S 31  is NO, and the process proceeds to step S 32 . 
     In step S 32 , the CPU  51  determines whether the lamp  58  has been turned on. 
     When the lamp  58  has not been turned on, a result of the determination in step S 32  is NO, and the process returns to step S 31  to repeat the process from step S 31  on down. That is, for a period during which the lamp timer T is not automatically reset and the lamp  58  is off, a loop process of steps S 31  and S 32  is repeated. The lamp timer T therefore continues maintaining a present value for this period. 
     Thereafter, when the lamp  58  has been turned on, a result of the determination in step S 32  is YES, and the process proceeds to step S 33 . In step S 33 , the CPU  51  determines whether the lamp  58  has been turned off. 
     When the lamp  58  continues being on, a result of the determination in step S 33  is NO, and the process proceeds to step S 34 . 
     In step S 34 , the CPU  51  increments the lamp timer T (T=T+1). 
     At this time, in the present embodiment, for example, the measured value of the lamp timer T in the log history information stored in the memory  52  is rewritten. Thus an accurate use time of the object lamp currently used as the lamp  58  is managed. 
     In step S 35 , the CPU  51  determines whether the measured value of the lamp timer T is less than the nominal life time T(life) (T&lt;T(life)). 
     When the measured value of the lamp timer T is less than the nominal life time T(life), a result of the determination in step S 35  is YES, and the process returns to step S 33  to repeat the process from step S 33  on down. 
     That is, while the lamp  58  is on, unless the lamp timer T reaches the nominal life time T(life), a loop process of steps S 33  to S 35  is repeated, and the measured value of the lamp timer T is incremented by one for one loop process. 
     When the lamp  58  is thereafter turned off, a result of the determination in next step S 33  is YES, and the process returns to step S 31  to repeat the process from step S 31  on down. 
     That is, until the lamp  58  is turned on next, or until the lamp timer T is automatically reset, the loop process of steps S 31  and S 32  is repeated. The lamp timer T therefore continues maintaining the present value for this period. 
     When the lamp timer T reaches the nominal life time T(life) while the lamp  58  is on, that is, while the loop process of steps S 33  to S 35  is repeated, a result of the determination in step S 35  is NO, and the process proceeds to step S 36 . 
     In step S 36 , the CPU  51  displays a lamp replacement alarm on the display unit  72 . The lamp replacement alarm refers to a message or the like prompting for replacement of the object lamp currently used as lamp  58  with another lamp because the use time of the object lamp has reached the nominal life time (or the use time of the object lamp will soon reach the nominal life time, as will be described later). 
     Thus, the form of presenting such a message is not specifically limited to image display, and may be any other presenting form such as voice output or the like. That is, the form of presenting the message is not specifically limited as long as the form allows the message indicating that a lamp replacement time has arrived to be presented to a lamp replacing worker (operator or the like). 
     In the example of  FIG. 10 , when the lamp timer T has reached the nominal life time T(life), the lamp replacement alarm is displayed. However, timing of displaying (presenting) the lamp replacement alarm is not necessarily limited to a point in time when the lamp timer T reaches the nominal life time T(life), and an arbitrary time can be adopted by a designer or the like as long as the arbitrary time is timing based on the nominal life time T(life) (for example a certain time before the nominal life time T(life)). That is, by only determining whether the lamp timer T has reached the adopted time in the process of step S 35 , the CPU  51  can perform the above-described lamp timer management process in exactly the same manner. 
     Incidentally, also after the process of step S 36 , the process returns to step S 33  to repeat the process from step S 33  on down. 
     As described above, the projector  33  can perform the projector lamp replacement time process of  FIG. 5  and the lamp timer management process of  FIG. 10 . The projector  33  can therefore solve the various problems described above. This will be described below in more detail. 
     As described above, an appropriate lamp driving controlling range is automatically determined by performing steps S 7  to S 10  in  FIG. 5  on the projector  33  side, and as a result, the object lamp substituted as lamp  58  this time is driven appropriately. Thereby, even when the object lamp that does not perfectly match the set range (the mode range in the present embodiment) of the lamp power supply unit  56  provided in advance is substituted as lamp  58 , the object lamp can be used safely. This is because a range where the code range specified by the lamp serial code attached to the object lamp and the mode range overlap each other is set as the lamp driving controlling range. Further, in the present embodiment, the lamp driving controlling range is determined after the Check sum confirmation process is performed in the process of step S 4  and then validity is confirmed, so that a danger of a lamp burst or a failure due to an input error by the operator can be avoided. That is, the lamp size problem can be solved. 
     Incidentally, a method for determining the lamp driving controlling range is not limited to the above-described example. When attention is directed to only the securing of safety, a method of determining a range not exceeding the maximum wattage (max watt) included in the lamp serial code as the lamp driving controlling range suffices. In consideration of various points such as solving the lamp gain problem to be described later and the like, it is desirable to adopt the example of the above-described method, that is, the determining method of determining the range in which the mode range and the code range overlap each other as the lamp driving controlling range. 
     In addition, as described above, the projector  33  can automatically reset the lamp timer T in the process of step S 11  in  FIG. 5 , then make a log setting in the process of step S 12 , and start the lamp timer management process (see  FIG. 10 ). Thereby, the log history information for the object lamp substituted this time as lamp  58  is properly stored, and the lamp use time (lamp timer T) is properly updated. Such log history information can be displayed as appropriate, and can also be output to the outside. Further, when the lamp timer reset button is pressed in the process of step S 1 , the lamp timer T is not immediately reset. The lamp timer T is automatically reset in the process of step S 11  only after validity is confirmed by the Check sum confirmation process in step S 4 . Thereby, even when the lamp life of the object lamp has ended within a guaranteed time of the lamp, the log history data can be used as means for officially proving that the lamp life of the object lamp has ended within the guaranteed time of the lamp. That is, the log history data can be used as one of materials for proving that the object lamp is defective. In addition, the log history information can be used as a material for determining the replacement time of a part whose periodic replacement time differs depending on light quantity (lamp size). That is, the lamp use history problem can be solved. 
     Though the above description is repeated, as described above, the lamp timer T is not immediately reset when the lamp timer reset button is pressed in the process of step S 1  in  FIG. 5 . The lamp timer T is automatically reset in the process of step S 11  only after explicit pop-up display of the lamp serial code input screen is made in the process of step S 2  and then a valid lamp serial code is input to the lamp serial code input screen, that is, only after validity is confirmed by the Check sum confirmation process in step S 4 . Therefore correct management of the lamp timer T can be expected. When the object lamp substituted this time as lamp  58  is not certified for the projector  33 , a lamp serial code should not be attached to the object lamp for a management reason. Therefore a correct lamp serial code is not input, so that a result of the Check sum confirmation process in step S 4  indicates an invalid code, a result of the determination in the process of step S 5  is NO, and an error display is made in the process of step S 6 . It is thereby possible to avoid a danger posed by using a non-certified object lamp as lamp  58 , that is, a danger of a failure of the projector  33 , a burst of the lamp  58 , or the like. Thus, the lamp management problem can be solved. 
     In addition, as is clear from the process of steps S 7  to S 10  in  FIG. 5  described above, a mode range set on the projector  33  side in advance is not used as the lamp driving controlling range as it is, but the lamp driving controlling range is properly determined also in consideration of the code range determined from the externally given lamp serial code. That is, in loading one of object lamps of various lamp sizes from a plurality of lamp manufacturers (lamp makers) that cannot be supposed at the time of design as lamp  58  into the projector  33 , the code range is externally input on the basis of the lamp serial code attached to the object lamp. Therefore the lamp driving controlling range can be optimized easily. As a result, a maximum lamp gain can be secured safely. That is, the lamp gain problem can be solved. 
     The nominal life time of the lamp is varied according to a lamp manufacturer (lamp maker) and lamp size (input rating), and even the same lamp may be improved in terms of life. In such a case, in the present embodiment, as described above, the nominal life time of the object lamp substituted as lamp  58  is included as “life hour” in the lamp serial code, and the “life hour” is used as the nominal life time T(life) to be compared with the lamp timer T in the lamp timer management process of  FIG. 10  described above. Then, when the lamp timer T has reached the nominal life time T(life), a lamp replacement alarm is displayed in the process of step S 36  in  FIG. 10 . This means that even when any one of object lamps having various nominal life times is substituted as lamp  58 , a lamp replacement alarm corresponding to the nominal life time of the object lamp can be automatically presented, that is, that the lamp replacement time problem can be solved. 
     Further, the measured value of the lamp timer T sequentially updated in the lamp timer management process of  FIG. 10  and the nominal life time T(life) are stored in the memory  52  in  FIG. 2  so as to be readable at any time as a part of the log history information for the object lamp being used as lamp  58 . Therefore, as shown in  FIG. 11 , for example, a ratio of the use time (the measured value of the lamp timer T) in the present conditions of the object lamp to the nominal life time T(life) can be readily displayed on the display unit  72  or the like. It is to be noted in this case that the ratio (%) is displayed rather than a fixed time (hr or the like), so that even when any one of object lamps having various nominal life times is substituted as lamp  58 , the ratio can be displayed on the display unit  72  or the like without the display form of  FIG. 11  being changed. 
     Further, as is clear from the configuration of  FIG. 1 , the projector  33  can be connected to external devices directly or indirectly, and send and receive various information to and from the external devices by communicating with the external devices directly or indirectly. 
     Thus, for inputting information, the input unit  71  of the projector  33  in  FIG. 2  does not necessarily need to be used, and an input function of an external device, for example an input function of the SM device  31 , a personal computer not shown in the figure, or the like can be used. Similarly, for presenting information, the display unit  72  of the projector  33  in  FIG. 2  does not necessarily need to be used, and various presenting functions such as a display function, a voice output function and the like of external devices can be used. Specifically, for example, a display function or the like of the SM device  31  or the personal computer not shown in the figure may be used. 
     Thereby, for example, a lamp replacing worker or the like can input the lamp serial code of the object lamp substituted as lamp  58  using the SM device  31  or the personal computer not shown in the figure, and be presented with various information based on log history information for the object lamp. 
     In addition, log history information for an object lamp being used as lamp  58  in a predetermined projector  33  can be easily transmitted to not only the SM device  31  and the TM device  21  but also the maintenance server  12 . It is therefore possible to collectively manage log history information for respective object lamps being used as respective lamps  58  in a plurality of projectors  33  in a unit of a screening place  22 , in a unit of a movie theater  11 , or in a unit of a service for the maintenance of a plurality of movie theaters  11 . 
     The lamp serial code in the above-described example is used in a state of being printed on a label or a paper medium. However, the lamp serial code is not specifically limited to the above-described example, and effect equal to or greater than that of the above-described example can be produced by using other media such for example as a bar code, an IC (Integrated Circuit) chip, or the like. The effect equal to or greater than that of the above-described example can be produced because the bar code, the IC chip, or the like can be generally applied to more various purposes as compared with the label or the paper medium, so that the application of the bar code, the IC chip, or the like to the lamp serial code is highly likely to give rise to various uses, and in this case, effect greater than that of the above-described example can be expected. 
     The lamp serial code having such various potentials can be readily created by for example making a device (not shown) for use by a lamp manufacturer (manufacturing maker) perform a lamp serial code generating process of  FIG. 12 . 
       FIG. 12  represents an example of the lamp serial code generating process. 
     In step S 51 , the device receives the input of lamp information by the lamp manufacturer (manufacturing maker) or the like. 
     The lamp information in this case refers to information excluding “Check sum”/“check sum” of information to be included in a lamp serial code. When a lamp serial code having the structure of  FIG. 7  described above is adopted, for example, the lamp information refers to “manufacturer code”, “max watt”, “min watt”, “life hour”, and “lamp serial”, as listed in the box of step S 51  in  FIG. 12 . Each piece of lamp information in this case does not necessarily need to be input by a same method, or does not necessarily need to be input in same timing. In addition, the order of the input is not specifically limited. 
     In any case, when all the lamp information has been input, the process proceeds from step S 51  to step S 52 . 
     In step S 52 , the device rearranges the lamp information. This rearrangement conforms to the structure of the lamp serial code. Thus, when the lamp serial code having the structure of  FIG. 7  described above is adopted, the lamp information is rearranged in order of “manufacturer code”, “max watt”, “min watt”, “life hour”, and “lamp serial”. 
     In step S 53 , the device calculates a check sum for the thus rearranged lamp information. That is, “Check sum”/“check sum” is calculated. 
     In step S 54 , the device generates a lamp serial code. That is, the lamp serial code is generated by adding the check sum calculated in the process of step S 53  to the lamp information rearranged in the process of step S 52 . For example, when the lamp serial code having the structure of  FIG. 7  is adopted, information formed by arranging the pieces of text information “Check sum/manufacturer code/max watt/min watt/life hour/lamp serial/check sum” is generated as the lamp serial code. 
     The series of processes described above can be carried out not only by hardware but also by software. When the series of processes is to be carried out by software, a program constituting the software is installed from a program recording medium onto a computer incorporated in special hardware, for example a computer including the CPU  51  incorporated in the projector  33  of  FIG. 2  described above, or a computer that can perform various functions by installing various programs thereon, for example a general-purpose personal computer. 
     As shown in  FIG. 2 , for example, the program recording medium storing the program to be installed onto a computer and set in a state of being executable by the computer is formed by the removable medium  74  as packaged medium including a magnetic disk (including flexible disks), an optical disk (including CD-ROM (Compact Disk-Read Only Memory) and DVD (Digital Versatile Disk)), a magneto-optical disk, a semiconductor memory or the like, or formed by the memory  52  where the program is stored temporarily or permanently, a hard disk not shown in  FIG. 2 , or the like. As necessary, the storing of the program onto the program recording medium is performed via the communicating unit  59  as an interface such as a router, a modem or the like using a wire or wireless communication medium such as a local area network, the Internet, digital satellite broadcasting or the like. 
     It is to be noted that in the present specification, the steps describing the program stored on the program recording medium include not only processes carried out in time series in the described order but also processes carried out in parallel or individually and not necessarily in time series. 
     In the present specification, a system refers to an apparatus or circuitry as a whole formed by a plurality of devices or circuits. 
     It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and alterations may occur depending on design requirements and other factors insofar as they are within the scope of the appended claims or the equivalents thereof.