Abstract:
A light source device for an endoscope, characterized by having a light source for supplying illuminating light to an object, endoscope connection means optically connected to an endoscope that has discrimination information for discriminating the kind of endoscope, discrimination means for discriminating the endoscope based on the discrimination information of the endoscope connected to the endoscope connection means, change means for the changing illumination condition of the illuminating light, and control means for controlling the change means based on the result of discrimination by the discrimination means.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     This is a Continuation Application of PCT Application No. PCT/JP2005/009480, filed May 24, 2005, which was not published under PCT Article 21(2) in English.  
         [0002]     This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2004-152699, filed May 24, 2004, the entire contents of which are incorporated herein by reference.  
         [0003]     This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2004-260135, filed Sep. 7, 2004, the entire contents of which are incorporated herein by reference.  
         [0004]     This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2004-260134, filed Sep. 7, 2004, the entire contents of which are incorporated herein by reference.  
       BACKGROUND OF THE INVENTION  
       [0005]     1. Field of the Invention  
         [0006]     The present invention relates to a light source device for an endoscope.  
         [0007]     2. Description of the Related Art  
         [0008]     Endoscopes are widely used in medical and other fields. An endoscope comprises a long thin insertion unit. Endoscopes allow observations to be made of organs and body tissues in body cavities and also allow various treatments employing instruments inserted into an instrument insertion channel as necessary.  
         [0009]     In an endoscope apparatus comprising such an endoscope, the subject body illuminates the object site by guiding illuminating light from a light source device employing a light guide etc., and an endoscope image is obtained by capturing the reflected light.  
         [0010]     The above endoscope apparatus can capture an image by an endoscope image capturing means, and perform signal processing by a signal processor device (hereinafter referred to as “processor”), and display endoscope image on an observation monitor. Consequently body tissues can be observed.  
         [0011]     As described above, an endoscope system comprises a light source device for supplying illuminating light to a light guide incorporated in the endoscope in order to irradiate the subject body. The light guide is used in combination with a light source device, and there are a variety of types of light guides. For example, in a type of light guide with a small incident end diameter, if the input illuminating light is too bright, it is probable that the heating value of the irradiated part in body cavities will become excessively large. Hence, when the endoscope is in use, the brightness of the supplied illuminated light has to be adjusted in accordance with the type of light guide. Consequently a light source device for an endoscope is disclosed that it should be able to obtain the appropriate brightness and light distribution of the illuminating light in accordance with the type of light guide connected to the light source device of an endoscope (for example, Patent Document 1).  
         [0012]      FIG. 1  is a construction diagram of such a light source device for an endoscope. The light source device of  FIG. 1  comprises light guide connector identifying means  81  and  82 , limiting means  80 , and light intensity adjustment means. The light guide connector identifying means  81  and  82  identifies the type of light guide connector  83  to be connected. The limiting means  80  limits the illuminating light that will be on the optical path of the illuminating light. The light intensity adjustment means appropriately adjusts the light intensity of the illuminating light incident on the light guide in accordance with the type of light guide connector  83  identified by the identifying means  81  and  82 . In order to prevent the tip of the light guide from causing burns and heat damage in body cavities, it is possible to supply illuminating light with appropriate brightness to the endoscope so that the brightness of the incident illuminating light is not excessively intense, even if the endoscope has a light guide with a small incident end diameter.  
         [0013]     In an endoscope apparatus, in usual cases of body tissue observation, the light source device emits white light (hereinafter referred to as normal light) in the visible light range, illuminates the object site of the subject body as frame sequential light by passing through a rotating filter such as RGB, for example, performs image processing by synchronization of an image signal based on the reflected light by a processor, and finally obtains color images (hereinafter referred to as the frame sequential method).  
         [0014]     Alternatively, the endoscope apparatus is provided with color chips in front of the imaging area of a solid-state image sensor installed in the endoscope, captures images by separating the reflected light of the normal light into RGB in the color chips, performs image processing via a processor, and obtains color images (hereinafter referred to as the simultaneous method).  
         [0015]     A variety of endoscope apparatuses for special light observations have been proposed since the optical absorption property and the optical scattering property are different according to the wavelength of the irradiating light in the body tissue.  
         [0016]     For example, as a frame sequential method, as described in Japanese Patent Application Publication No. 2002-336196, an endoscope apparatus for fluorescent observation, which makes a diagnosis by utilizing a difference between normal tissue and lesions in autofluorescence generated from the body tissue by irradiating pump light such as ultraviolet rays and blue light on a body tissue, has been proposed in recent years.  
         [0017]     As described in Japanese Patent Application Publication No. 2000-41942, an endoscope apparatus for infrared light observation, which enables an observation of the depth of the body tissue by irradiating infrared light on the body tissue as illuminating light, has been also been proposed. In addition, as described in Japanese Patent Application Publication No. 2002-95635, an endoscope apparatus for narrow-band light observation, which enables an observation around a superficial portion of the mucous membrane of the body tissue by irradiating the body tissue with blue narrow-band light as illuminating light, has been proposed.  
         [0018]     Endoscopes used for the above observations need to be able to make at least two types of observations, a normal light observation and at least one special light observation. For example, with the use of the endoscope for fluorescent observation, normal light observation and fluorescent observation are possible. With the use of the endoscope apparatus for infrared light observation, normal light observation and infrared light observation are possible. Normal light observation and narrow-band light observation are possible using the endoscope apparatus for narrow-band light observation.  
         [0019]     Similarly, in the simultaneous method, at least one special light observation in addition to normal light observation can be conducted, and, for example, normal light observation and a narrowband light observation are possible with the use of a narrowband light observation endoscope, and normal light observation and a fluorescent observation are possible with the use of a fluorescent observation endoscope.  
         [0020]     In these endoscopes for special light observation, the switching operation between normal light observation and special light observation is performed by operating an operation unit of the endoscope, a processor, a switch provided on the front panel of the light source device, or a foot switch for the endoscope, etc.  
         [0021]     In recent years, there have been increasing demands for a plurality of special light observation modes to be available to be used with one set of processor and light source device. The usage depends on the user, particularly whether the endoscope will be used for internal medicine or for surgery. For example, a physician may use an endoscope as a narrowband observation endoscope, a surgeon may use the endoscope as a fluorescent observation endoscope, and another surgeon may use the endoscope as an infrared light observation endoscope.  
         [0022]     Here, the special light observations have different spectroscopic characteristics for the illuminating light supplied from the light source device, different transmission characteristics of the objective optical system of the endoscope, different types of solid-state image sensors, and different signal processing in their processor devices, etc., in accordance with the observation mode.  
         [0023]     As described above, conventional light source devices are provided with filters for special light observation modes in an observation mode switching turret comprising a plurality of observation mode filters corresponding to the observation mode.  
         [0000]     Patent Document 1:  
         [0024]     Japanese Patent Application Publication No. 2003-210403  
         [0000]     Patent Document 2:  
         [0025]     Japanese Patent Application Publication No. 2002-336196  
         [0000]     Patent Document 3:  
         [0026]     Japanese Patent Application Publication No. 2000-41942  
         [0000]     Patent Document 4:  
         [0027]     Japanese Patent Application Publication No. 2002-95635  
       SUMMARY OF THE INVENTION  
       [0028]     The light source device relating to the present invention comprises a light source for supplying illuminating light to an object, endoscope connection means optically connected to an endoscope that has identification information for identifying the type of endoscope, identification means for identifying the endoscope based on the identification information of the endoscope connected to the endoscope connection means, change means for changing the illumination condition of the illuminating light, and control means for controlling the change means based on the result of identification by the identification means.  
         [0029]     The light source device for an endoscope relating to the present invention comprises endoscope connection means, which can be selectively connected to a plurality of types of endoscopes, a light source for generating illuminating light supplied to an endoscope connected to the endoscope connection means, an optical system guiding illuminating light generated from the light source to the endoscope, an observation filter turret comprising a plurality of types of observation filters for limiting the wavelength range of light from the light source in accordance with the observation mode of the endoscope and that can set an observation filter corresponding to the observation mode of the endoscope on an optical path of the optical system, and a neutral density filter turret comprising a plurality of types of neutral density filters for darkening light from the light source in accordance with the observation mode of the endoscope and that can set a neutral density filter corresponding to the endoscope on an optical path of the optical system.  
         [0030]     The light source device for an endoscope relating to the present invention comprises endoscope connection means that can be selectively connected to a plurality of types of endoscopes, a detection sensor provided in the endoscope connection means for detecting the type of endoscope, detection means for detecting the type of endoscope based on a signal from the detection sensor, memory for storing the setting content in accordance with the type of endoscope, and control means for making an automatic setting in accordance with the setting content stored in the memory based on the detection result of the detection means. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0031]      FIG. 1  shows diagrams explaining the configurations of a light source device for an endoscope relating to prior art;  
         [0032]      FIG. 2  is an overview of the whole configuration of the endoscope system relating to embodiment 1 of the first mode;  
         [0033]      FIG. 3  is an overview of the light source device in the endoscope system of embodiment 1 of the first mode;  
         [0034]      FIG. 4  is a diagram showing the configuration of the optical system of the light source device of embodiment 1 of the first mode;  
         [0035]      FIG. 5  is a cross-sectional diagram of the connector receiver unit of the light source device of the light source device of embodiment 1 of the first mode;  
         [0036]      FIG. 6  is a diagram showing an example of the light-shielding spring of embodiment 1 of the first mode;  
         [0037]      FIG. 7  shows diagrams explaining the relation between the light guide connector and the type identification means in embodiment 1 of the first mode;  
         [0038]      FIG. 8A  shows diagrams showing combinations of the detection states of two optical sensors in embodiment 1 of the first mode;  
         [0039]      FIG. 8B  shows diagrams showing combinations of the detection states of two optical sensors in embodiment 1 of the first mode;  
         [0040]      FIG. 8C  shows diagrams showing combinations of the detection states of two optical sensors in embodiment 1 of the first mode;  
         [0041]      FIG. 9  is an example of the operation panel of embodiment 1 of the first mode;  
         [0042]      FIG. 10  is a cross-sectional diagram of the connector receiver unit of embodiment 2 of the first mode;  
         [0043]      FIG. 11  is a diagram showing an example of the hinge and the coil spring of embodiment 2 of the first mode;  
         [0044]      FIG. 12  shows diagrams explaining the relation between the light guide connector and the type identification means in embodiment 2 of the first mode;  
         [0045]      FIG. 13A  shows diagrams showing combinations of the detection states of the three optical sensors in embodiment 2 of the first mode;  
         [0046]      FIG. 13B  shows diagrams showing combinations of the detection states of the three optical sensors in embodiment 2 of the first mode;  
         [0047]      FIG. 13C  shows diagrams showing combinations of the detection states of the three optical sensors in embodiment 2 of the first mode;  
         [0048]      FIG. 13D  shows diagrams showing combinations of the detection states of the three optical sensors in embodiment 2 of the first mode;  
         [0049]      FIG. 14A  shows diagrams showing combinations of the detection states of the three optical sensors in a case in which the response moving member is fixed in embodiment 2 of the first mode;  
         [0050]      FIG. 14B  shows diagrams showing combinations of the detection states of the three optical sensors in a case in which the response moving member is fixed in embodiment 2 of the first mode;  
         [0051]      FIG. 15  is a diagram showing the entire configuration of an endoscope system comprising the light source device for an endoscope of the second mode;  
         [0052]      FIG. 16  is a block diagram showing the inner configuration of the light source device of  FIG. 15 ;  
         [0053]      FIG. 17  is a block diagram showing an inner configuration of the control board of  FIG. 16 ;  
         [0054]      FIG. 18  shows a front view of the light source device of  FIG. 15 ;  
         [0055]      FIG. 19  is an enlarged view showing the configuration of the operation panel of  FIG. 18 ;  
         [0056]      FIG. 20  is a front view of the light source device showing an example of variations of  FIG. 18 ;  
         [0057]      FIG. 21  is an enlarged view showing the configuration of the operation panel of  FIG. 20 ;  
         [0058]      FIG. 22  is a schematic perspective view showing an optical path from the xenon lamp of  FIG. 2 ;  
         [0059]      FIG. 23  is a front view showing the surroundings of the observation mode switching turret of  FIG. 22 ;  
         [0060]      FIG. 24  is a front view showing the surroundings of the neutral density mesh turret of  FIG. 22 ;  
         [0061]      FIG. 25  is a front view of the neutral density mesh turret showing an example ( 1 ) of a variation of  FIG. 24 ;  
         [0062]      FIG. 26  is a front view of the neutral density mesh turret showing an example ( 2 ) of a variation of  FIG. 24 ;  
         [0063]      FIG. 27  is a perspective view showing a configuration of the neutral density mesh turret of  FIG. 24  in detail;  
         [0064]      FIG. 28  is a perspective view showing an example of a modification in the attachment of the neutral density mesh of  FIG. 27 ;  
         [0065]      FIG. 29  is a perspective view showing the back of the neutral density mesh turret of  FIG. 28 ;  
         [0066]      FIG. 30  is an overview explanatory diagram showing the relative positions in the state in which the connector of the endoscope of  FIG. 15  is connected to the light source;  
         [0067]      FIG. 31  is a perspective view showing the surroundings of the connector receiver unit of  FIG. 22 ;  
         [0068]      FIG. 32  is a cross-sectional view of the surroundings of the connector receiver unit of  FIG. 31 ;  
         [0069]      FIG. 33  is a cross-sectional view of the light source connector of the normal flexible endoscope to the connector receiver unit of  FIG. 32 ;  
         [0070]      FIG. 34  is a cross-sectional view of a case in which the light source connector of the high-brightness rigid endoscope is connected to the connector receiver unit of  FIG. 32 ;  
         [0071]      FIG. 35  is a cross-sectional view of a case in which the light source connector of the normal rigid endoscope is connected to the connector receiver unit of  FIG. 32 ;  
         [0072]      FIG. 36  is an overview explanatory diagram showing the relation between the first and second photosensors and the first and the second protrusions in  FIG. 32 ;  
         [0073]      FIG. 37  is an overview explanatory diagram showing the relation between the first and second photosensors and the first and second protrusions in  FIG. 33 ;  
         [0074]      FIG. 38  is an overview explanatory diagram showing the relating between the first and second photosensors and the first and the second protrusions in  FIG. 34 ;  
         [0075]      FIG. 39  is an overview explanatory diagram showing the relation between the third photosensor and the third protrusion in the state in which the third photosensor is OFF in the second mode;  
         [0076]      FIG. 40  is an overview explanatory diagram showing the relation between the third photosensor and the third protrusion in the state in which the third photosensor is ON in the second mode;  
         [0077]      FIG. 41  is the main flowchart showing the operation of the MPU in the second mode;  
         [0078]      FIG. 42  is a flowchart of an endoscope switching control operated by the MPU in the second mode;  
         [0079]      FIG. 43  is a flowchart of a memory write-in control operated by the MPU in the second mode; and  
         [0080]      FIG. 44  is a flowchart of the observation mode switching control operated by the MPU in the second mode. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0000]     &lt;First Mode&gt; 
         [0081]     From the perspective of safety, it is desirable to have an endoscope that is safe for both operators of the endoscope system and patients, or subject bodies, etc., at all times, even when a failure occurs in a part of the endoscope system, including failures in the light source device (hereinafter referred to as a single failure).  
         [0082]     There is a light source device that satisfies this requirement: it has a switch that an operator can switch to a safe brightness according to the type of connected endoscope. The switch is provided on the operation panel. In such a light source device, if there is a failure of the light guide, the light intensity of the illuminating light of the light guide, in general, can be adjusted from the operation panel. However, even if an illuminating light with unexpected light intensity is input into the endoscope due to a signal failure of the light guide, the light intensity cannot be adjusted without operation of the switch by the operator. In an emergency such as this, a light source device with improved safety that enables light intensity adjustment via operation of the switch by an operator, is required.  
         [0083]     In the present mode, a light source device for an endoscope that performs automatic adjustment within the light source device to ensure a safe light intensity even during a failure in means of identifying the type or the connection state of the light guide of the endoscope, etc., and that prevents heat damage to bodies and the light guide, is explained.  
         [0084]     In the following description, details of the preferred embodiment of the present invention are set forth with reference to the drawings.  
       Embodiment 1  
       [0085]     An explanation of a light source device of the first embodiment is provided below.  FIG. 2  is an overview of the configuration of the entire endoscope system relating to embodiment 1 of the present invention. An endoscope system  3  comprises an endoscope  2  and a light source device  1 . The light source device  1  supplies illuminating light into the endoscope  2 .  
         [0086]     The endoscope  2  is used for observation and treatment in body cavities, for example. The endoscope  2  comprises an insertion unit  4 , an operation unit  5 , and a light guide cable  6 . The operation unit  5  is provided in the proximal end side of the insertion unit  4 . The light guide cable  6  is connected to the side surface of the operation unit  5 . The tip of the light guide cable  6  is provided with a light guide connector  7 . The light guide connector  7  can be connected to a connector receiver unit  8 , which is the output end of the light source device  1 . The illuminating light supplied from the light source device  1  into the endoscope  2  is output from the distal end of the insertion unit  4  configured in the endoscope  2  toward the object. The image of the illuminated object is guided by an image guide configured in the endoscope  2 , and observation and diagnosis are performed via the optical system.  
         [0087]     It should be noted that in the case of adopting a TV camera system, when capturing images by attaching a TV camera head  9  in which an imaging apparatus such as CCD is built, the diagnosis is made in the following manner. Signal processing of the captured image&#39;s electrical signal from the TV camera head  9  is first performed in a camera control unit (CCU)  10 . Next, the processed picture signal is transmitted to a monitor  11 . The object image is projected on the screen of the monitor  11 , and observation and diagnosis are made.  
         [0088]      FIG. 3  is an overview of the light source device  1  in the endoscope system of  FIG. 2 . The light source device  1  comprises a lamp  12  within its device body. The illuminating light output from the lamp  12  is input into a light guide  13  of the light guide connector  7  of the endoscope  2  connected to the connector receiver unit  8  via the optical system.  
         [0089]      FIG. 4  is a diagram showing the configuration of the optical system of the light source device  1  of  FIG. 3 . Arranged on the optical path of the illuminating light from lamp  12  are an output side lens  14 , an aperture  15 , a first input side lens  16 , a second input side lens  17 , and limiting means  18  in sequence.  
         [0090]     The output side lens  14  first receives the illuminating light output from the lamp  12  and forms a collected light beam. The aperture  15  is arranged in a region immediately before the collecting point and controls the brightness by limiting the illuminating light. Note in  FIG. 3  that the aperture  15  is controlled by a light control circuit  19  and is adjusted so that the brightness of the object is constant. The illuminating light is input into the first input side lens  16  via the aperture  15 , and is converted into a collimated light beam. After being converted into a collimated light beam, the illuminating light is input into the second input side lens  17 , and is collected once again. The collected illuminating light is input into the tip of the light guide  13  of the light guide connector  7  of the endoscope  2  connected to the connector receiver unit  8 .  
         [0091]     The limiting means  18  include a mask etc. The limiting means  18  is arranged in a position between the first input side lens  16  and the second input side lens  17  where the illuminating light converted into the collimated light beam by the first input side lens  16  is input. Based on an instruction from a control unit not shown in the drawing, the illuminating light input into the tip of the light guide  13  of the light guide connector  7  is limited by the mask etc. By the limiting means  18 , the illuminating light input into the tip of the light guide  13  is limited to an appropriate light intensity in accordance with the type of light guide connector  7  of the endoscope  2 .  
         [0092]      FIG. 5  is a cross-sectional diagram of the connector receiver unit  8  of the light source device  1 . Two identification means are provided with the connector receiver unit  8  in the light source device  1 .  
         [0093]     The type identification means, which is one of the two identification means, comprises an optical sensor  20  and a response moving member  21  with a light-shielding unit  63 . Force in the direction of the left of  FIG. 5  is constantly applied to the response moving member  21  by an elastic body such as a spring along with a guide means not shown in the drawing. The response moving member  21  is provided so as to be movable toward the direction of the insertion axis of the light guide connector  7  when the light guide connector  7  of the endoscope  2  is connected to the connector receiver unit  8 . The leftmost end of the response moving member  21  is provided with a stopper  61  fixed by a setscrew  62 . The stopper  61  prevents the response moving member  21  from moving to the left.  
         [0094]     Another identification means, the connection identification means, comprises an optical sensor  26  and a light-shielding spring  27  made of an elastic member. The optical sensor  26  is fixed on a bracket  33  by an engaging hook etc. and detects the presence/absence of the shielded object. The bracket  33  is screwed via setscrew  34  provided in the connector receiver unit  8 . The light-shielding spring  27  is fixed in an approximate cantilevered state via setscrew  30  provided in the connector receiver unit  8 . In addition, the light-shielding spring  27  is bent below a concave area  29  and is given force to form a slope  64 . Accordingly, even when the light guide connector  7  is not connected, the illuminating light from the lamp  12 , which is a light source, is shielded by the light-shielding spring  27 . As a result, leakage of a large amount of light from the light source device  1 , entering the endoscope  2 , does not occur.  
         [0095]      FIG. 6  is a diagram showing an example of the light-shielding spring  27 . The light-shielding spring  27  is provided with an upward bend  31 . If the light-shielding spring  27  is incorporated into the connector receiver unit  8 , a black-colored insulation sheet  32  with good light shielding effect, or the like, for example, is fixed on the upward bend  31 .  
         [0096]     When the light guide connector  7  of the endoscope  2  is inserted into the insertion hole  28  of the connector receiver unit  8 , the light-shielding spring  27  is pushed obliquely upward by a tip of the light guide connector  7  at a low strength (See  FIG. 5 ). The light-shielding spring  27  withdraws obliquely upward making an approximate arc trajectory. The tip of the insulation sheet  32  moves obliquely upward when the light-shielding spring  27  moves obliquely upward for withdrawal.  
         [0097]     The amount of movement of the insulation sheet  32  is set to be larger than the sensing area of the optical sensor  26 . Therefore, the insulation sheet  32  is located in the sensing area of the optical sensor  26  when the light guide connector  7  is not connected; however, it withdraws outside the sensing area when the light guide connector  7  is connected. By doing this, that is, by moving the insulation sheet  32 , the optical sensor  26  recognizes the state of “shielding object absent”, sensing that the shielding object is absent in the sensing area. When the light guide connector  7  is not connected, the optical sensor  26 , shielded by the insulation sheet  32 , recognizes the state of “shielding object present”.  
         [0098]     The optical sensor  26  constitutes a part of a secondary circuit in the light source device  1 . On the other hand, the light-shielding spring  27  constitutes a part of a patient circuit in the light source device  1 . The insulation sheet  32  is provided in order to secure the insulation distance between the optical sensor  26  and the light-shielding spring  27  from the perspective of safety so that the optical sensor  26  of the secondary circuit and the light-shielding spring  27  of the patient circuit are not in electrical contact with each other.  
         [0099]     The circuit configuration of the light source device, when the light guide connector  7  is not connected, may have the upward bend  31  of the light-shielding spring  27  arranged at a position in the direct sensing area. In such a case, when the light guide connector  7  is inserted, the upward bend  31  of the light-shielding spring  27  is to be arranged at a position outside of the sensing area of the optical sensor  26 .  
         [0100]      FIG. 7  is a diagram explaining the relationship between the light guide connector and the type identification means in the present embodiment. With regard to the light guide connector shown in  FIG. 7 ,  FIG. 7 ( a ) is the light guide connector  25  for low brightness and  FIG. 7 ( b ) is the light guide connector  23  for middle brightness. The light guide connector  25  for low brightness (hereinafter referred to as the low-brightness connector) in  FIG. 7 ( a ) is not provided with a flange configuration. Meanwhile, the light guide connector  23  for middle brightness (hereinafter referred to as the middle brightness connector) in  FIG. 7 ( b ) is provided with a flange unit  24 . Given that the height dimension of the flange unit  24  is X, the height dimension of the flange unit  24  is determined by the position of the left end of the response moving member  21 , that is, where the flange unit  24  has contact with the light guide connector, when the middle brightness connector  23  is connected from the position of the left end of the response moving member  21  when the light guide connector is not inserted.  
         [0101]     Depending on the presence/absence of the flange unit  24 , the position of the response moving member  21  when the low-brightness connector  25  is connected is different from when the middle brightness connecter  23  is connected by the height dimension X, as shown in  FIG. 7 . The height dimension X is set at the distance required when the low-brightness connector  25  moves from the initial position of the response moving member  21  shown in  FIG. 7 ( a ) to the position where a light-shielding unit  63  of the response moving member  21  falls within the sensing area of the optical sensor  20  shown in  FIG. 7 ( b ). Consequently, as shown in  FIG. 7 ( a ), when the low-brightness connector  25  is connected, the light-shielding unit  63  of the response moving member  21  is located outside the sensing area of the optical sensor  20 , and the optical sensor  20  recognizes the state of “shielding object absent”. When the middle brightness connector  23  is connected as in (b), the response moving member  21  is pushed in by the dimension X against the force of the spring in a state such that the end of the flange unit  24  (the right end in  FIG. 7 ) is in contact with the end of the response moving member  21  (the left end in  FIG. 7 ). Thus, the light-shielding unit  63  of the response moving member  21  is moved into the sensing area of the optical sensor  20 , and the optical sensor  20  recognizes the state of “shielding object present”. In such a manner, it is possible to identify the low-brightness connector  25  and the middle brightness connector  23  via the optical sensor  20  and the response moving member  21 .  
         [0102]     By the two identification means, the connection identification means consisting of the optical sensor  26  and the light-shielding spring  27  and the type identification means consisting of the optical sensor  26  and the response moving member  21 , it is possible to distinguish the normal detection states of a case in which the low-brightness connector  25  is connected, a case in which the middle brightness connector  23  is connected, and a case in which the light guide connector is not connected.  
         [0103]      FIG. 8A  is a diagram showing combinations of the detection states of two optical sensors  20  and  26  when the light guide is normally connected in the present embodiment. “O” in  FIG. 8A  represents a case of the “shielding object present” state in the sensing area being determined by each of the optical sensors  20  and  26 . At that time, in  FIG. 4 , a control unit not shown in the drawing receives a short signal. “X” represents a case of the “shielding object absent” state in the sensing area being determined for each of the optical sensors  20  and  26 . At that time, the control unit receives an open signal. For example, when “shielding object present” is detected in the optical sensor  20  and “shielding object absent” is detected in the optical sensor  26 , the combination of the detection states is represented as (O,X). The detection state of the two optical sensors when the light guide is not connected, the state when the low-brightness connector  25  is connected, and the state when the middle brightness connector  23  is connected are as follows. 
    (1) When the light guide connector is not connected, the combination is (X,O). The optical sensor  20  detects “shielding object absent”, and the optical sensor  26  detects “shielding object present” due to the insulation sheet  32 .     (2) When the low-brightness connector  25  of  FIG. 7 ( a ) is connected, the combination is (X,X). The optical sensor  20  remains as “shielding object absent” since the response moving member  21  does not move, and the optical sensor  26  detects “shielding object absent” due to the withdrawal of the insulation sheet  32 .     (3) When the middle brightness connector  23  of FIG.  7 ( b ) is connected, the combination is (O,X). The optical sensor  20  detects “shielding object present” since the response moving member  21  moves by the dimension X to the rear, and the optical sensor  26  detects “shielding object absent” due to the withdrawal of the insulation sheet  32 .      
         [0107]     As described above, from the combinations of the detection states of the two optical sensors it is possible to distinguish the state from among the following: the state in which the light guide connector is not connected, the state in which the low-brightness connector is connected, and the state in which the middle brightness connector is connected. On the basis of the combination of the detection states of the two optical sensors in  FIG. 4 , the control unit not shown in the drawing instructs the limiting means  18  to output the illuminating light with appropriate light intensity.  
         [0108]      FIG. 8B  is a diagram showing the detection states of the two optical sensors when the optical sensor  20  fails. Even if the middle brightness connector  23  is connected, the state cannot be recognized properly due to the failure of the optical sensor  20 , and indicates a detection state identical to the state when the low-brightness connector  25  is connected (X,X). Even in such a case, the control unit of the light source device  1  causes the device to output illuminating light with a light intensity appropriate to the time when the low-brightness connector  25  is connected.  
         [0109]      FIG. 8C  is a diagram showing the detection states of the two optical sensors when the optical sensor  26  fails. Even if the light guide connector is not connected, the state cannot be recognized properly due to the failure of the optical sensor  26 , and this indicates a detection state identical to the state when the low-brightness connector  25  is connected (X,X). Even in such a case, the illuminating light is shielded by the light-shielding spring  27 , preventing the illuminating light from being leaked out of the light source device  1 .  
         [0110]     As explained with reference to  FIG. 8 , even when a failure occurs such as a disconnection of the optical sensor  20  or  26  or a connection terminal being pulled out, the light intensity output from the light source device  1  is appropriately limited on the basis of the change in the detection states of the optical sensors  20  and  26 , and therefore, safety problems can be prevented.  
         [0111]     It should be noted that in a case of failure caused by a loss of the insulation sheet  32  from the attached position, even though the light guide connector is not connected, the optical sensor  26  recognizes the state of “shielding object absent”, and a detection state identical to that of  FIG. 8C  (X,X) can be obtained. Even when the light guide is not connected, the illuminating light is shielded by the light-shielding spring  27 . For that reason, the illuminating light cannot leak out of the light source device  1 .  
         [0112]     Based on the combinations of the detection states of the two optical sensors of  FIG. 8 , the display on the operation panel of the light source device  1  can be switched  
         [0113]      FIG. 9  is an example of the operation panel of the present embodiment. A variety of setting switches  37  and a display LED  38  are arranged on the operation panel  36 . As an example of the setting switches  37 , a brightness switch  39  for setting the brightness, an air-supply/water-supply switch  41 , and a transmission illumination switch  42 , etc., are shown. As an example the display LEDs  38 , a brightness display LED  40  and a transmission illumination display LED  43  are shown.  
         [0114]     The brightness switch  39  is a switch for switching the illuminating light between the middle brightness and the low-brightness. The brightness switch  39  is used, for example, when connecting a surgical light guide with a tolerance to the middle brightness illuminating light. The air-supply/water-supply switch  41  is a switch for switching the air supply or water supply function ON and OFF. The transmission illumination switch  42  is a switch realizing a transmission illumination function, which is used when the position of the endoscope in a body cavity must be visually identified by irradiating with a high light intensity for a short time period. The air-supply/water-supply switch  41  and the transmission illumination switch  42  are used in a flexible scope for the digestive tract alone. Assume that the flexible scope for the digestive tract in this description is used at a low brightness.  
         [0115]     Switching of the displays of the operation panel  36  in the present mode is explained with examples. When connecting the light guide of the flexible scope for a digestive tract used with low brightness, the unused brightness switch  39  is set to OFF and the brightness display LED  40  is turned off. The air-supply/water-supply switch  41  and the transmission illumination switch  42  are set to ON, and the transmission illumination display LED  43  is turned on.  
         [0116]     For example, when connecting a light guide used with a middle brightness such as a surgical light guide, the brightness switch  39  is set to ON and the brightness display LED  40  is turned on. The unused air-supply/water-supply switch  41  and the transmission illumination switch  42  are set to OFF and the transmission illumination display LED  43  is turned off.  
         [0117]     When the light guide connector is not connected, in order to reduce noise, pump driving in the light source device  1  is brought to a halt. In addition, under the assumption that none of the functions indicated by the setting switches  37  and display LED  38  on the operation panel  36  are to be used, all setting switches  37  are set to OFF and the display LED  38  is turned off.  
         [0118]     As described above, according to the light source device of the present mode, type identification means for identifying the type of the light guide connected to the connector receiver unit and connection identification means for identifying whether or not the light guide is connected to the connector receiver unit are provided. Additionally, a light-shielding spring, which is an optical shielding means for preventing the illuminating light from the light source lamp from leaking out of the light source device when the light guide connector is not connected, is provided. By the type identification means and the connection identification means, the presence/absence of the connection of the light guide connector and the type of the connected light guide connector are identified. When the light guide connector is not connected, the illuminating light does not leak out due to the light-shielding spring, which is the optical shielding means. When the light guide connector is connected, the intensity is controlled so as to adjust to a safe light intensity based on the identification result.  
         [0119]     The connection state of the light guide and the types of connected light guide connectors are determined by combining the identification result of each of the type identification means and the connection identification means. Therefore, with a failure in a single identification means, based on the combination of the identification result of the two identification means, it is possible to prevent the light guide from heat damage, and prevent the subject body from heat damage, and so on. Furthermore, in accordance with the type of the connected light guide connector, it is possible to realize a display on the operation panel that is operator-friendly and prevents operation errors.  
       Second Embodiment  
       [0120]     The light source device of the present embodiment is to be explained. The present embodiment is different from the first embodiment in the following two ways: there are two optical sensors constituting the type identification means for identifying the type of the light guide connector; and there is a hinge constituting the light-shielding means for shielding illuminating light. The configuration of the optical system in the endoscope system and the light source device is the same as that of the system relating to the first embodiment; therefore, in this description the explanation of the configuration is omitted and the feature different from the first embodiment alone is explained.  
         [0121]      FIG. 10  is a cross-sectional diagram of the connector receiver unit of the light source device of the endoscope system relating to the present embodiment. The type identification means for identifying the type of the light guide connector comprises two optical sensors  43  and  44 , and a response moving member  45 . The connection identification means for identifying the presence/absence of the connection of the light guide connector comprises an optical sensor  48 , a hinge  49 , and a coil spring  50  (see  FIG. 11 ). The response moving member  45  comprises two light-shielding units  67  and  68  in the present embodiment. The explanations of operations of the response moving member  45  and the light-shielding units  67  and  68  are omitted since they are the same as the response moving member  21  of the first embodiment. The hinge  49  and the coil spring  49  operate as light-shielding means.  
         [0122]      FIG. 11  is a diagram showing an example of the hinge and the coil spring. The hinge  49  is fixed by a setscrew  30  provided on the connector receiver unit  8  in an approximate cantilevered state. In addition, a force is applied to the hinge  49  to constantly press the slope  69  of the concave area  29  by the coil spring  50 . When the light guide connector  22  is not connected, the hinge  49  covers the insertion hole  28 . At that time, the detection state of the optical sensor  48  is “shielding object present” due to the insulation sheet  32  adhered on the upward bend  51  of the hinge  49 .  
         [0123]     The light guide connector  22  of the endoscope  2  is inserted into the insertion hole  28  of the connector receiver unit  8 . By doing this, the hinge  49  is pushed obliquely upward by the tip of the light guide connector  22  at a low strength (see  FIG. 10 ). The hinge  49  withdraws obliquely upward making an approximate arc trajectory around the axis that serves as a fulcrum. The tip of the insulation sheet  32  is, along with the obliquely upward withdrawal movement of the hinge  49 , pushed by the upward bend  51  of the hinge  49  and moves obliquely upward.  
         [0124]     The amount of movement of the insulation sheet  32  is set larger than the sensing area of the optical sensor  48 . When the light guide connector  22  is not connected, the insulation sheet  32  is located in the sensing area of the optical sensor  48 . When the light guide connector  22  is connected, the insulation sheet  32  is withdrawn to outside of the sensing area. Then, by the movement of the insulation sheet  32  in the optical sensor  48 , the detection state becomes “shielding object absent” as the shielding object is not present in the sensing area.  
         [0125]      FIG. 12  is a diagram explaining the relationship between the light guide connector and the type identification means in the present embodiment. Among the light guide connectors in  FIG. 12 ,  FIG. 12 ( a ) is a light guide connector  25  for low brightness,  FIG. 12 ( b ) is a light guide connector  23  for middle brightness  23 , and  FIG. 12 ( c ) is a light guide connector  46  for high-brightness. Similarly to the first embodiment, the light guide connector  25  for low brightness (hereinafter referred to as the low-brightness connector) of (a) is not provided with a flange configuration; however, the light guide connector  23  for middle brightness (hereinafter referred to as the middle brightness connector) of (b) is provided with a flange unit  24  with the height dimension being X. The light guide connector  46  for high-brightness (hereinafter referred to as a high-brightness connector) of (c) is provided with a flange unit  47  with the height dimension being X+Y.  
         [0126]     When inserting the light guide connector into the insertion hole  28 , the location of the response moving member  45  varies depending on the presence/absence of the flange configuration and the height dimension of the flange unit. In (a), it is not located in any of the sensing areas of the two optical sensors  43  and  44  constituting the type identification means. In (b), the light-shielding unit  67  of the response moving member  45  is within the sensing area of the optical sensor  43  located on the near side of the insertion entry point of the light guide connector. In (c), the light-shield unit  68  of the response moving member  45  is within the sensing area of the optical sensor  44 .  
         [0127]     The connection state of the light guide connector can be classified by the combination of the detection states of the optical sensors  43 ,  44 , and  48 . For example, when the optical sensor  43  detects “shielding object absent”, the optical sensor  44  detects “shielding object present”, and the optical sensor  48  detects “shielding object absent”, it is represented as (X, O, X).  
         [0128]      FIG. 13A  is a diagram showing combinations of the detection states of the three optical sensors  43 ,  44  and  48  when a light guide is connected normally in the present embodiment. The definitions of “O” and “X” in  FIG. 13A  are the same as those in the first embodiment.  
         [0129]     In  FIG. 13A , the combinations of the detection states of the three optical sensors  43 ,  44  and  48  are, regarding the connection state of the light guide connector, all different depending on whether the state is unconnected, low-brightness connector connected, middle brightness connector connected, or high-brightness connector connected, respectively represented by (X, X, O), (X, X, X), (O, X, X), or (X, O, X). Therefore, on the basis of the combination of the detection state of the three optical sensors, it is possible to determine the connection state of the light guide connector.  
         [0130]      FIG. 13B  is a diagram showing the combinations of the detection states of the three optical sensors when the optical sensor  43  fails in the present embodiment. When the optical sensor  43  cannot correctly detect the presence/absence of the shielding object, even in the state in which the middle brightness connector is connected, the detection state shows (X, X, X), which is the same as the detection state when the low-brightness connector is connected, due to incorrect sensing. On the basis of the detection state of the optical sensor, even if the middle brightness connector is actually connected, the light intensity of the illuminating light is adjusted to the light intensity appropriate for the time when the low-brightness connector is connected by limiting means  18  of  FIG. 4 .  
         [0131]      FIG. 13C  is a diagram showing the combinations of the detection states of the three optical sensors when the optical sensor  44  fails in the present embodiment. The connection state of the high-brightness connector cannot be correctly sensed, even in a state in which the high-brightness connector is actually connected, the detection state is (X, X, X), which is incorrect in that it indicates that a low-brightness connector is connected. Since the light intensity of the illuminating light is based on the detection state of the optical sensors, when a high-brightness connecter is connected, the light intensity is adjusted to the intensity it would be if a low-brightness connector were connected by the limiting means  18  of  FIG. 4 .  
         [0132]      FIG. 13D  is a diagram showing combinations of detection states of the three optical sensors when the optical sensor  48  fails. If the presence/absence of the connection of the light guide connector cannot be sensed correctly, the detection state is (X, X, X) even if the light guide connector is not connected; this state is incorrect in that it indicates that a low-brightness connector is connected. In such a case, the illuminating light is shielded by the hinge  49  and cannot leak out of the light source device  1 .  
         [0133]      FIG. 14A-14B  is a diagram showing combinations of the detection states of the three optical sensors when the response moving member  45  of the light source device  1  is fixed on the flange unit of the light guide connector. Being fixed in the description means a state in which the elastic force of a spring etc. that gives force to the response moving member  45  is no longer effective, and the response moving member cannot move freely, staying in a particular position even with the insertion or ejection of a light guide connector.  
         [0134]     Assume that when connected to the high-brightness connector, the response moving member  45  is fixed on the flange unit  47  of the connector.  FIG. 14A  is a diagram showing the combinations of the detection states of the three optical sensors when the response moving member is fixed at the position of the flange unit  47  and a high-brightness connector is connected. Because it is fixed during the high-brightness connector  46  connection, even in the state in which the light guide connector is not connected after ejecting the high-brightness connector  46 , the optical sensor  44  still senses the state of “shielding object present”, and the detection state changes from (X, O, X), which is the high-brightness connector connected state, to (X, O, O).  
         [0135]     The control unit, which receives a signal of the state (X, O, O) when the light guide connector is not connected, recognizes that a failure is occurring with regard to the state of the connector receiver unit  8  of the light source device, and switches the operation mode to “failure mode”. In failure mode, the illuminating light is adjusted to have a low light intensity as in the low-brightness connector connection, and the operator is notified of failure occurrence via a flashing display etc. on the operation panel  36  of  FIG. 9 .  
         [0136]     When the response moving member  45  is fixed at a position of the flange unit  47  of the connector and the high-brightness connector is connected, the low-brightness connector  25  or the middle brightness connector  23  may be connected by mistake after ejecting the high-brightness connector  46 . In such a case, the detection state is (X, O, X), which is the same as the case of connecting the high-brightness connector in a normal state. However, since the operation mode has been previously switched to the failure mode, the light intensity output is the same as the light intensity when the low-brightness connector  25  is connected, and illuminating light with a high light intensity cannot be output from the light source device  1 .  
         [0137]      FIG. 14B  is a diagram showing the combinations of the detection states of the three optical sensors when the response moving member  45  is fixed at the flange unit  24  and when connected to the middle brightness connector. Because it is fixed when the middle brightness connector  23  is connected, the optical sensor  43  senses the state of “shielding object present” and the detection state is changed from (O, X, X) to (O, X, O), even in the state in which the light guide connector is not connected after ejecting the middle brightness connector  23 .  
         [0138]     The control unit, which receives a signal of the state (O, X, O) when the light guide connector is not connected, recognizes a failure occurring with regard to the state of the connector receiver unit  8  of the light source device, and switches the operation mode to “failure mode”. In failure mode, the illuminating light is adjusted to have a low light intensity as when the low-brightness connector is connected, and the operator is notified of a failure occurrence via a flashing display etc. on the operation panel  36  of  FIG. 9 .  
         [0139]     Assume that the response moving member  45  is fixed, when connecting to the middle brightness connector, at the position of the flange unit  24  of the connector. After ejecting the middle brightness connector, the low-brightness connector  25  may be connected by mistake. Since the response moving member  45  is fixed, the detection state is (O, X, X), which is the same state as when the middle brightness connector is connected in a normal state. However, after ejecting the middle brightness connector  23 , the fixing of the response moving member  45  is recognized, and the operation mode is switched to the failure mode. Consequently, in a case of the low-brightness connector connection being incorrectly sensed as the middle brightness connector connection since the response moving member  45  is fixed, the light intensity is adjusted to the light intensity of the low-brightness connector  25  connection, and illuminating light with a high light intensity cannot be output from the light source device  1 .  
         [0140]     Similarly, a case is examined in which, after the response moving member  45  is fixed, the middle brightness connector  23  is ejected and the high-brightness connector  46  is connected when connecting to the middle brightness connector at the position of the flange unit  24 . The response moving member  45  is, even in the fixed state, forcibly moved toward the right in  FIG. 10  by the high-brightness connector  46 . The detection state of the three optical sensors is (X, O, X), which is the same as the state that exists when connecting the high-brightness connector in the normal state. In such a case, since the fact that the response moving member  45  is fixed is recognized when ejecting the middle brightness connector  23  and since the operation mode has been switched to the failure mode, illuminating light with a high light intensity cannot be output from the light source device  1 .  
         [0141]     In response to the failure caused by the loss of the insulation sheet  32 , the same processing is performed as in the case of failure in the optical sensor  48  explained with reference to  FIG. 13D .  
         [0142]     In the present embodiment, the display on the operation panel of the light source device  1  can be switched based on the combination of the detection state of the three optical sensors. Similarly to the previous embodiment, the operation panel  36  of  FIG. 9  is used, for example. The types of switches  37  and the display LED  38  arranged on the operation panel  36  are the same as those of the first embodiment.  
         [0143]     A brightness switch  39  is a switch for switching the illuminating light to high-brightness or to low brightness, and is used when connecting a surgical light guide with a tolerance against the high-brightness illuminating light. An air-supply/water-supply switch  41  is a switch for switching ON/OFF the air supply or water supply function. A transmission illumination switch  42  is a switch realizing a transmission illumination function, which is used when the position of the endoscope in a body cavity is visually confirmed with by irradiating the body cavity with a high light intensity for a limited time period. The air-supply/water-supply switch  41  and the transmission illumination switch  42  are used only in a flexible scope for digestive tracts. Assume that the flexible scope for digestive tracts in this description is used at a middle brightness.  
         [0144]     The switching of the display on the operation panel  36  in the present embodiment is explained with an example. When connecting the light guide of the flexible scope (used at a middle brightness) for use in a digestive tract , the brightness switch  39  is set to OFF and the brightness display LED  40  is turned off. The air-supply/water-supply switch  41  and the transmission illumination switch  42  are set to ON, and the transmission illumination display LED  43  is lit.  
         [0145]     When connecting a light guide used with high-brightness such as a surgical light guide, the brightness switch  39  is set to ON and the brightness display LED  40  is lit. The air-supply/water-supply switch  41  and the transmission illumination switch  42 , which are not to be used, are set to OFF, and the transmission illumination display LED  43  is turned off.  
         [0146]     In the state of the light guide used with low brightness being connected or the light guide not being connected, pump driving in the light source device  1  is stopped in order to reduce noise. In addition, since none of the functions indicated by the setting switch  37  and the display LED  38  on the operation panel  36  are used, all the setting switches  37  are set to OFF and the display LED  38  is turned off.  
         [0147]     As explained above, according to the light source device of the present embodiment, the type identification means for identifying the type of the connected light guide connector comprises two optical sensors. Identification of more types of light guide connectors in addition to a low-brightness connector, a middle brightness connector and a high-brightness connector becomes possible. The light-shielding means for preventing the illuminating light from leaking outside of the light source device when the light guide connector is not connected is configured with a hinge. When the light guide connector is inserted, the upward bend of the hinge moves, making an approximate arc trajectory. By using the hinge, a stable trajectory can be obtained without making clearance in consideration of the variation of the trajectory. Therefore, it is possible to realize a small light source device for an endoscope.  
         [0148]     Note that the present embodiment employs three optical sensors and a hinge; however, these do not limit the invention. For example, the use of a hinge as the light-shielding means in the light source device of the first embodiment, or the use of a light-shielding spring as the light-shielding means in the light source device of the present embodiment, are also possible. Regarding the number of optical sensors, the above first and second embodiments of the light source device use two or three; however, the number of provided sensors may be larger than two or three.  
         [0149]     Additionally, the present invention is not limited to the above-described embodiments, but various modifications may be made for its implementation.  
         [0150]     The light source device for an endoscope of the present embodiment comprises a light source lamp for generating illuminating light, a connector receiver to which the light guide connector of an endoscope is detachably connected, connection identification means for determining whether or not the light guide connector is connected to the connector receiver, type identification means for identifying the type of the light guide connector connected to the connector receiver, and a control unit for controlling based on the identification result of the connection identification means and the type identification means.  
         [0151]     In the above light source device for an endoscope, the control unit can set the light intensity of the light source lamp.  
         [0152]     Additionally, the light source device for an endoscope further comprises light-shielding means, arranged on an optical path of the illuminating light emitted from the light source lamp, for shielding the illuminating light from the connector receiver when the light guide connector is not connected.  
         [0153]     In the light source device for an endoscope, the light-shielding means is movable between the first position, shielding the illuminating light from the connector receiver when the light guide connector is not connected, and the second position, where the light-shielding means withdraws from the first position when the light guide connector is connected, and the connection identification means detects whether the light-shielding means is located at the first position or in the second position. When detecting that the light-shielding means is located at the first position, it is determined that the light guide connector is not connected to the connector receiver, and when detecting that the light-shielding means is located at the second position, it is determined that the light guide connector is connected to the connector receiver.  
         [0154]     In the light source device for an endoscope, the type identification means that is movable along the direction of the light guide connector inserted into/ejected from the connector receiver comprises a response moving member moving to a position in accordance with the type of light guide connector connected to the connector receiver and detection means for detecting the position to which the response moving member has moved, and determines the type of light guide connector connected to the connector receiver based on the position of the response moving member detected by the detection means.  
         [0155]     In the light source device for an endoscope, the light-shielding means is configured with an elastic member.  
         [0156]     In the light source device for an endoscope, the light-shielding means is configured with a hinge.  
         [0157]     In the light source device for an endoscope, the control unit switches the setting switch to the display unit of the light source device for an endoscope on the basis of the identification result of the connection identification means and the type identification means.  
         [0158]     As described above, according to the present embodiment, it is possible to determine the presence/absence of the light guide connector connection and the type of connected light guide connector. The illuminating light can be adjusted to an appropriate light intensity in accordance with the connection state of the light guide connector.  
         [0000]     &lt;Second Mode&gt; 
         [0159]     Every endoscope has the maximum allowable light intensity that can enter the endoscope inlet end determined in accordance with its intended use, such as for internal medicine or surgical use. For that reason, the light source device is required to automatically control the maximum light intensity to be supplied in accordance with the type of endoscope, and is also required to have a neutral density filter adopted to the type of endoscope.  
         [0160]     However, when the maximum allowable light intensity of a common surgical endoscope is “1”, for example, the intensity varies such that a surgical endoscope with high-brightness has twice as much, and an internal medicine endoscope with a high-brightness has 1.3-1.6 times as much; a neutral density filter is thus required for darkening.  
         [0161]     If all of the neutral density filters, an optical filter, and a special light filter are provided on the turret plate of the observation mode switching turret, the turret will become large, resulting in the entire device having a large size.  
         [0162]     Every endoscope has a different setting content in accordance with its type, e.g., internal medicine or surgical use. For example, a flexible endoscope is provided with an air-supply channel and can supply air from an air pump provided in the light source device. On the other hand, since a rigid endoscope does not contain an air-supply channel, air cannot be supplied from the air pump provided in the light source device.  
         [0163]     For that reason, for the light source device that is connected to a flexible endoscope and that supplies air from an air pump, if the flexible endoscope is removed and a rigid endoscope is connected, the air pump remains running. In this case, the air pump in the light source device must be turned off manually.  
         [0164]     Accordingly, the conventional light source device requires changes in settings to be made by the user him/herself in accordance with the connected endoscope, which is an inconvenience.  
         [0165]     In the present mode, a downsized light source device, despite comprising various optical filters, filters for special observation, and neutral density filters, is explained. In the present mode, additionally, a light source device that can change the setting automatically in accordance with the type of connected endoscope is explained. In the following description, details of the embodiment of the present invention are set forth first.  
         [0166]      FIG. 15  is a diagram showing the configuration of an entire endoscope system comprising the light source device for an endoscope of the present mode. An endoscope system  101  comprises a plurality of types of endoscopes  102 , a light source device for an endoscope (hereinafter referred to as a light source device)  103 , a video processor  104 , and a monitor  105 . Note that a foot switch  106  is to be connected to the light source device  103 .  
         [0167]     The plurality of types of endoscopes  102  comprises a normal flexible endoscope  111 , a normal rigid endoscope  113 , and a high-brightness rigid endoscope  114 .  
         [0168]     A camera head  115  is installed in each of the normal rigid endoscopes  113  and the high-brightness rigid endoscope  114 . An electrical connector  117  is provided at the end of a camera cable  116  extended from the camera head  115 . The electrical connector  117  is detachably connected to the video processor  104 . Note that an image pickup device for picking up endoscopic images supplied from the normal rigid endoscope  113  and the high-brightness rigid endoscope  114  is embedded in the camera head  115 , although it is not shown in the drawing.  
         [0169]     The normal rigid endoscope  113  and the high-brightness rigid endoscope  114  are provided with an insertion unit  121  and an eyepiece  122 . The insertion unit  121  is inserted into the abdominal cavities of a patient via a trocar not shown in the drawing. The eyepiece  122  is connected serially to the proximal end of the insertion unit  121 .  
         [0170]     The normal rigid endoscope  113  is provided with a light source connector  124   c  on the end of a light guide cable  123  extending from the eyepiece  122 . Alight source connector  124   c  is provided. The light source connector  124   c  is detachably connected to the light source device  103 . The high-brightness rigid endoscope  114  is provided with a light source connector  124   d  on the end of the light guide cable  123  extending from the eyepiece  122 . The light source connector  124   d  is detachably connected to the light source device  103 .  
         [0171]     The normal flexible endoscope  111  comprises an insertion unit  131  and an operation unit  132 . The insertion unit  131  is a long and thin section inserted into body cavities. The operation unit  132  is a part serially connected to the proximal end of the insertion unit  131 .  
         [0172]     The normal flexible endoscope  111  is provided with a light connector  124   a  on the end of a universal cable  133  extended from the operation unit  132 . The light source connector  124   a  is detachably connected to the light source device  103 .  
         [0173]     An electrical cable  135  is extended from the side of the light source connector  124   a.  An electrical connector  136  is attached to the end of the electrical cable  135 . The electrical connector  136  is detachably connected to the video processor  4 .  
         [0174]     The insertion unit  131  comprises a bendable tube unit  137 , a bent section  138  and a distal end  139 . The bendable tube unit  137  is flexible. The bent section  138  is attached to the distal end side of the bendable tube unit  137 . The distal end  139  is attached to the distal end of the bent section  138 . The distal end  139  is installed with an image pickup device, as explained later, for picking up images of an observation target in body cavities. Note that in  FIG. 15  the normal flexible endoscope  111  is connected to the light source device  103  and the video processor  104 .  
         [0175]      FIG. 16  is a block diagram showing the inner configuration of the light source device of  FIG. 15 . The normal flexible endoscope  111  has a light guide  131   a  inserted and set. Since the light source connector  124   a  is detachably connected to the light source device  103 , the light guide  131   a  can supply the illuminating light.  
         [0176]     The illuminating light supplied from the light source device  103  is transmitted to the distal end of the insertion unit  131  by the light guide  131   a.  The illuminating light transmitted to an output end face of the light guide  131   a  is for illuminating the observation target part of the subject body from an illumination optical system  139   a  provided in the end face.  
         [0177]     An objective optical system  139   b  is set on the distal end  139  of the insertion unit  131 . The objective optical system  139   b  is adjacent to the illumination optical system  139   a,  and is for capturing the light from the observation target part and for forming optical images. A CCD  139   c  is provided as an image pickup device in the back of the objective optical system  139   b.    
         [0178]     A signal line  131   b  is extended from the CCD  139   c.  The signal line  131   b  is inserted through the insertion unit  131 , runs through the electrical cable  135 , and reaches the electrical connector  136 . Therefore, the signal line  131   b  is electrically connected to the video processor  104  via the electrical connector  136 .  
         [0179]     The CCD  139   c  is driven by a driving signal output from a CCD driving circuit, not shown in the drawing, provided in the video processor  104 . The CCD  139   c  generates an image pickup signal by performing optoelectrical conversion of the formed optical images, and the image pickup signal is output to the video processor  104 .  
         [0180]     The video processor  104  processes the image pickup signal output from the CCD  139   c  by an image signal processing circuit not shown in the drawing, and generates a standard image signal. The video processor  104  outputs the image signal to a monitor  105  and causes the monitor  105  to display the image on the display screen.  
         [0181]     In addition, the normal flexible endoscope  111  has an air-supply channel  131   c  inserted and set. Since the light source connector  124   a  is detachably connected to the light source device  103 , the air-supply channel  131   c  can supply the air.  
         [0182]     The air provided from the light source device  103  is supplied to the distal end side of the insertion unit  131  by the air-supply channel  131   c.  The air supplied to the output end face of the air-supply channel  131   c  is supplied toward the most distal end side of the objective optical system  139   b  from a nozzle  139   d  provided on the surface of the end face.  
         [0183]     The light guide  131   a,  the illumination optical system  139   a,  and the objective optical system  139   b  in both the normal rigid endoscope  113  and the high-brightness rigid endoscope  114  have the same configuration. Note that since the normal rigid endoscope  113  and the high-brightness endoscope  114  are provided with an image transmission optical system such as a relay lens system in the posterior of the objective optical system  139   b  (not shown in the drawing), optical images can be transmitted to the eyepiece  122 .  
         [0184]     Next, the light source device  103  is set forth.  
         [0185]     The light source device  103  comprises a connector receiver unit  141  as an endoscope connection unit, a xenon lamp  142  as a light source, a switching regulator  143 , a temperature switch  144 , a control board  145 , an endoscope connection detection sensor  146 , a front panel  147 , an optical system  148 , a diaphragm  149 , an observation mode switching turret  151 , a neutral density mesh turret  152 , an air-supply pump (hereinafter referred to as the pump)  153 , a foot-switch connection unit  154 , an automatic/manual lighting switching switch  155 , and a communication connector  156 .  
         [0186]     One of the light source connectors  124   a,    124   c  or  124   d  of the endoscope  102  (the normal flexible endoscope  111  with two types of maximum light intensity able to be set, the normal rigid endoscope  113 , and the high-brightness rigid endoscope  114 ) is selectively detachably connected to the connector receiver unit  141 .  
         [0187]     The connector receiver unit  141  is provided with the endoscope connection detection sensor  146 . The endoscope connection detection sensor  146  detects the type of connected endoscope  102 . The endoscope connection detection sensor  146  is configured with, for example, three photosensors, first through third, explained later. Note that the configuration of the endoscope connection detection  146  is set forth in detail later.  
         [0188]     At this point, the setting content of the light source device  103  varies in accordance with the type of endoscope  102  (normal flexible endoscope  111 , normal rigid endoscope  113 , or high-brightness endoscope  114 ).  
         [0189]     For example, since a normal flexible endoscope  111  is provided with the above-explained air-supply channel  131   c,  it is possible to supply the air via the pump  153  of the light source device  103 . On the other hand, the normal rigid endoscope  113  and the high-brightness rigid endoscope  114  have a configuration in which the pump  153  is not used because the air supply is unnecessary.  
         [0190]     Additionally, in the endoscope  102  (normal flexible endoscope  111 , normal rigid endoscope  113 , or high-brightness rigid endoscope  114 ), the maximum light intensity of the illuminating light that can be entered is determined in accordance with the type.  
         [0191]     The present embodiment has a configuration in which the type of endoscope  102  (normal flexible endoscope  111 , normal rigid endoscope  113 , or high-brightness rigid endoscope  114 ) connected to the light source device  103  is detected, and the light source device  103  is automatically set. In addition, the present embodiment has a configuration in which the maximum light intensity of the illuminating light supplied is automatically set in accordance with the type of endoscope  102  connected to the light source device  103 .  
         [0192]     The xenon lamp  142  is a lamp utilizing electrical discharge in xenon gas. The spectrum of the xenon lamp  142  is similar to natural sunlight, and therefore natural light illumination (high illumination intensity) light can be obtained.  
         [0193]     The switching regulator  143  is a power source stabilizer adopted a method for converting input voltage into pulses by switching between ON and OFF at a high speed and for obtaining smoothed and stable DC voltages. The switching regulator  143  converts input voltage supplied from the control board  145  into DC voltage and supplies the voltage to each part of the device.  
         [0194]     The temperature switch  144  is provided in proximity to the xenon lamp  142 . The temperature switch  144  turns ON when the temperature around the xenon lamp  142  reaches a prescribed value and outputs an ON signal to the control board  145 . By exchanging signals, the control board  145  can turn OFF the xenon lamp  142 .  
         [0195]     The automatic/manual lighting switching switch  155  is a switch that allows the selection of automatic or manual lighting of the xenon lamp  142  when the power of the light source device  103  is ON.  
         [0196]     Connected to the communication connector  156  is a communication cable  157  of the video processor  104 .  
         [0197]     The optical system  148  comprises a lens group for collecting the light generated by the xenon lamp  142  in the input end face of the light guide  158 . The light guide  158  is connected to selected one of the light source connectors  124   a,    124   b  and  124   d,  and projects from the selected light source connector.  
         [0198]     The observation mode switching turret  151 , the neutral density mesh turret  152 , and the diaphragm  149  are provided on an optical path comprising this lens group.  
         [0199]     Each of the turrets  151  and  152  and the diaphragm  149  is provided with motors  159   a,    159   b,  and  159   c,  respectively.  
         [0200]     The diaphragm  149  has a formation of a fan-shaped concavity  149   a  (see  FIG. 22 ). The diaphragm  149  can limit the illuminating light to a desired light intensity by moving the position of the fan-shaped concavity  149   a  on the optical path by driving the motor  159   c.    
         [0201]     In the observation mode switching turret  151  and the neutral density mesh turret  152 , a desired filter is set on the optical path by driving the motors  159   a  and  159   b.  The configurations of the observation mode switching turret  151  and the neutral density mesh turret  152  are given in detail later.  
         [0202]     A foot switch cable  106   a  for the foot switch  106  is connected to the foot switch connection unit  154 . The front panel  147  can have various settings and show various displays. Details of the configuration of the front panel  147  are given later.  
         [0203]     The pump  153  can supply air to the normal flexible endoscope  111 . The air from the pump  153  is supplied from the connector receiver unit  141  to the normal flexible endoscope  111  via a channel not shown in the drawing.  
         [0204]     The control board  145  comprises an MPU (Micro Processing Unit)  161 , FRAM (Ferroelectric Random Access Memory)  162 , and ROM (READ Only Memory) or SRAM (Static Random Access Memory); the ROM and SRAM are not shown in the drawing.  
         [0205]     The MPU (Micro Processing Unit)  161  is for controlling each of the units in the device. The ROM or SRAM is for storing programs of the MPU  161 . The FRAM  162  is for storing data being run.  
         [0206]     It should be noted that the FRAM  162  stores the settings of the light source device  103  in advance according to the type of endoscope  102  connected, as explained later. The settings are rewritable.  
         [0207]      FIG. 17  is a block diagram showing an inner configuration of the control board of  FIG. 16 . The control board  145  comprises, in addition to the MPU  161  and the FRAM  162 , an observation mode switching turret control unit  63 , a neutral density mesh turret control unit  164 , a diaphragm control unit  165 , an endoscope connection detection unit  166 , a pump control unit  167 , a lamp lighting control unit  168 , a temperature switch detection unit  169 , a foot switch detection unit  171 , a communication control unit  172 , an automatic/manual lighting switch control unit  173 , and a front panel control unit  174 . The above control units are controlled by the MPU  161 .  
         [0208]     The observation mode switching turret control unit  163  controls the motor  159   a  to set a desired optical filter of the observation mode switching turret  151  on the optical path. Note that the observation mode switching turret  151  is provided with a spare halogen lamp  175  in case the xenon lamp  142  goes out.  
         [0209]     When the xenon lamp  142  goes out, the observation mode switching turret control unit  163  provides light to the endoscope  102  by driving the motor  159   a  of the observation mode switching turret  151  so that the spare halogen lamp  175  is set on the optical path.  
         [0210]     The neutral density mesh turret control unit  164  controls the motor  159   b  to set a desired filter of the neutral density mesh turret on the optical path.  
         [0211]     The diaphragm control unit  165  controls the motor  159   c  for adjusting the position of the diaphragm  149  so that the illuminating light from the xenon lamp  142  has the desired light intensity.  
         [0212]     In the present embodiment, if the light source connectors ( 124   a,    124   c,    124   d ) of the endoscope  102  are pulled out of the connector receiver unit  141 , the communication cable  157  is pulled out, a failure occurs in the endoscope connection detection unit  166 , or the power of the video processor  104  is off, the diaphragm  149  is controlled so as to have a prescribed opening.  
         [0213]     By doing this, the light intensity of the illuminating light required for medical treatment can be maintained without totally closing the diaphragm  149  even when the endoscope connection detection unit  166  detects incorrectly due to a failure or when the communication cable  157  is disconnected or pulled out of the light source device  103  during a medical examination.  
         [0214]     Note that the connector receiver unit  141  has a configuration in which, when the light source connectors ( 124   a,    124   c,    124   d ) are not connected, an opening/closing member (the flexible member  206  in  FIG. 32 , explained later) prevents unintended illuminating light from leaking out.  
         [0215]     The endoscope connection detection unit  166  detects the ON/OFF signal from the endoscope connection detection sensor  146  and outputs it to the MPU  161 .  
         [0216]     The pump control unit  167  controls and drives the pump  153 .  
         [0217]     The temperature switch detection unit  169  detects the ON signal from the temperature switch  144  and outputs it to the MPU  161 .  
         [0218]     The foot switch detection unit  171  detects the ON/OFF signal of the foot switch  106  and outputs it to the MPU  161 .  
         [0219]     The communication control unit  172  controls communications between the video processor  104  etc. and the MPU  161 .  
         [0220]     The lamp lighting control unit  168  controls the lighting of the xenon lamp  142 .  
         [0221]     The automatic/manual lighting switching control unit  173  detects the signal from the automatic/manual lighting switching switch  155  and outputs the signal to the MPU  161 .  
         [0222]     Here, when the power is turned on in conventional light source devices, lighting is automatic in endoscopes for surgery (rigid endoscopes) and lighting is manually controlled in endoscopes for internal medicine (flexible endoscope) because the usage environments are different.  
         [0223]     In the present embodiment, either automatic lighting or manual lighting of the xenon lamp  142  is possible in accordance with the user usage environment when the power of the light source device  103  is turned ON.  
         [0224]     In other words, if the automatic/manual lighting switching switch  155  is pressed by a user in advance and is set to the automatic setting, the xenon lamp  142  automatically lights upon start-up when the power is turned on. In addition, with the manual setting the automatic/manual lighting switching switch  155  manually controls the lighting of the xenon lamp  142  via a switch on the operation panel (e.g. the “LAMP” switch  187   a  of  FIG. 19 ) upon start-up when the power is turned on.  
         [0225]     By doing this, either automatic lighting or manual lighting of the xenon lamp  142  in the light source device  103  is possible when the power is turned on, in accordance with the user usage environment.  
         [0226]     The front panel control unit  174  can control various settings and displays in the front panel  147  via the MPU  161 .  
         [0227]     On the basis of various settings on the front panel  147 , the MPU  161  controls each unit in the light source device  103  by controlling each unit of the control board  145 .  
         [0228]     The present embodiment detects the connection state in the connector receiver unit  141  and automatically sets each of the various settings stored in the RAM  162  based on the connection state.  
         [0229]     Next, the front panel  147  of the light source device  103  is explained.  
         [0230]      FIG. 18  shows a front view of the light source device in  FIG. 15 . The front panel  147  of the light source device  103  comprises a power switch  181 , an operation panel  182 , and the connector receiver unit  141 .  
         [0231]     A power display  181   a  is provided on the power switch  181 . In other words, when the power switch  181  is pressed and the power of the light source device  103  comes on, the power display  181   a  lights up and indicates a power-on state.  
         [0232]     One of the light source connectors  124   a,    124   c,  or  124   d  of the endoscope  102  (the normal flexible endoscope  111 , the normal rigid endoscope  113 , or the high-brightness endoscope  114 ) is selectively connected to the connector receiver unit  141 .  
         [0233]     An example of a configuration of the operation panel  182  is shown in  FIG. 19 .  
         [0234]      FIG. 19  is an enlarged view showing the configuration of the operation panel of  FIG. 18 . The operation panel  182  comprises a brightness display unit  183 , a spare lamp display unit  184 , an air-supply setting display unit  185 , a usage time display unit  186 , a lamp control setting display unit  187 , and an illumination mode setting display unit  188 .  
         [0235]     The brightness display unit  183  is provided with an indicator  183   a  for displaying the brightness of the xenon lamp  142 . The spare lamp display unit  184  lights when the xenon lamp  142  has gone out and is switched to the spare halogen lamp  175  of the observation mode switching turret  151 .  
         [0236]     The display “spare lamp” of the spare lamp display unit  184  flashes when the spare halogen lamp  175  is disconnected, pulled out, or not in place.  
         [0237]     The air-supply setting display unit  185  comprises an air-supply on/off switch  185   a  and an air-level switch  185   b.  The air-supply on/off switch  185   a  is a switch for supplying air to the endoscope  102 . The air-supply level switch  185   b  is a switch for setting the air-supply level.  
         [0238]     The usage time display unit  186  comprises a counter reset switch  186   a  and the usage time display unit  186   b.  The usage time display unit  186   b  displays the usage time of the xenon lamp  142 .  
         [0239]     The lamp control setting display unit  187  comprises a lamp on/off switch  187   a,  an automatic/manual setting switch  187   b,  and operation buttons  187   c.    
         [0240]     The lamp on/off switch  187   a  is a switch for turning on/off the lamp after the power switch  181  is turned on. In the lamp on/off switch  187   a,  the switch has to be held down; this prevents the lamp from being turned off unintentionally.  
         [0241]     The automatic/manual setting switch  187 b is for switching between automatic/manual performance of brightness adjustment.  
         [0242]     The operation buttons  187   c  are buttons for turning up or down the brightness adjustment value when the brightness is adjusted manually. Manipulation of the up/down buttons gradually increases the setting value or gradually decreases the setting value.  
         [0243]     The illumination mode setting display unit  188  comprises a filter mode switch  188   a  and a special light observation display unit  188   b.    
         [0244]     The filter mode switch  188   a  is a switch for selecting the special light observation mode when performing special light observation.  
         [0245]     The special light observation display unit  188   b  comprises a mode LED  188   c  indicating three special light observation modes usable (valid) for special light observations such as narrow bandwidth light observation or fluorescent light observation. Note that in  FIG. 19  the mode LED  188   c  shows three names for the special light observation modes, “A”, “B”, and “C”.  
         [0246]     In the configuration in which a board including optional functions of the special light observation (or a DIP switch etc.) is present in the video processor  104 , green light is on in the mode LED  188   c  corresponding to an available special light observation mode when the power switch  181  is held down and the light source device  103  is in a power ON state in the special light observation display unit  188   b.  For example, if special light observations A and B are being used, the special light observation mode indicator lights “A” and “B” light in green, and “C” remains off.  
         [0247]     In the special light observation display unit  188   b,  when the endoscope  102  corresponding to each of the special light observation devices is connected, the mode LED  188   c  corresponding to the special light observation mode corresponding to the special observation mode of the connected endoscope  102  remains lit in green and the other displays are turned off. For example, for connecting an endoscope that enables the special light observation A, the special light observation mode “A” remains lit in green, “B” is turned off, and “C” remains off.  
         [0248]     In addition, in this situation, the filter mode switch  188   a  is turned on and is active. This allows the special light observation display unit  188   b  to be placed into special light observation mode by holding down the filter mode switch  188   a;  the display corresponding to each of the special light observation devices changes from white to green (the switch may be a foot switch or a switch on the endoscope etc., depending on the setting). For example, “A” is switched from being lit in green to being lit in white. The mode LED  188   c  is formed so that, in the special light observation display unit  188   b,  it is difficult to recognize the display (characters) when they are not lit.  
         [0249]     It should be noted that the operation panel may be configured as shown in  FIG. 20  and  FIG. 21 .  
         [0250]      FIG. 20  is a front view of an example of a variation of the light source device shown in  FIG. 18 .  FIG. 21  is an enlarged view showing the configuration of the operation panel of  FIG. 20 . As shown in  FIG. 20  and  FIG. 21 , the operation panel  182 B comprises a special light observation mode display unit  188   d  in an illumination mode setting display unit  188 B.  
         [0251]     In the special light observation mode display unit  188   d,  a dot LED  188   e  is provided above each mode LED  188   c.  When the endoscope  2  corresponding to the special light observation is connected and the corresponding special light observation is prepared, the dot LED  188   e  is lit.  
         [0252]     For example, in the special light observation mode display unit  188   d,  the LEDs  188   e  which correspond to the special light observation modes “A” and “B” not including functions of the special light observations “A” and “B”, emit green light, and the LED  188   e  which corresponds to the mode “C” remains being off.  
         [0253]     Keeping the same conditions, if the endoscope  102  can perform special light observation “A” and is connected to the light source device  103 , the special light observation mode display unit  188   d  will have only the dot LED  188   e  above the special light observation light “A” lit. If the endoscope  102  can perform special light observation “B”, then the special light observation mode display unit  188   d  will have only the LED  188   e  above the special light observation light “B” lit.  
         [0254]     When this happens, the filter mode switch  188   a  will also be lit and the device will be in a condition in which the filter mode switch  188   a  can be used.  
         [0255]     In the light source device  103 , when the filter mode switch  188   a  is held down, the special light observation light “A” of the mode LED  188   c  lights in white. This indicates the condition in which an observation via the special light observation “A” can be conducted.  
         [0256]     When returning to a normal observation, if the filter mode switch  188   a  is held down once again, the light source device  103  will have the special light observation light “A” of the mode LED  188   c  lit in green and normal observation can be conducted.  
         [0257]     Next, the configurations of the observation mode switching turret  151  and the neutral density mesh turret  152  are explained in detail.  
         [0258]      FIG. 22  is a schematic perspective view showing an optical path from the xenon lamp of  FIG. 16 . The observation mode switching turret  151  is set in the xenon lamp  142  side. The neutral density mesh turret  152  is set in the connector receiver unit  141  side. Note that the connector receiver unit  141  has the endoscope connection detection sensor  146 . The configuration of the endoscope connection detection sensor  146  is described in detail later.  
         [0259]     Both the observation mode switching turret  151  and the neutral density mesh turret  152  are provided with an initial position detection pin  189 .  
         [0260]      FIG. 23  is a front view showing the surroundings of the observation mode switching turret of  FIG. 22 .  FIG. 24  is a front view showing the surroundings of the neutral density mesh turret of  FIG. 22 . Both the observation mode switching turret  151  and the neutral density mesh turret  152  have their initial position detection pin  189  detected via an initial position detection switch  190 , and the initial position of the rotation position can thus be detected.  
         [0261]     As shown in  FIG. 23 , the observation mode switching turret  151  comprises five observation filters in addition to the spare halogen lamp  175 .  
         [0262]     These observation filters may be, for example, a special observation light transmission filter for infrared light  191   a,  a normal observation light transmission filter  191   b,  a special observation light transmission filter for narrowband light  191   c,  a special observation light transmission filter for fluorescent light  191   d,  and a special observation light transmission filter for fluorescent/infrared light  191   e.  These filters are arranged from the right side of the spare halogen lamp  175 .  
         [0263]     It should be noted that such an arrangement is made because the usages are mainly the following: a: normal  191   b ⇄narrowband  191   c,  b: fluorescent/infrared  191   e ⇄fluorescent  191   d,  and c: fluorescent/infrared  191   e ⇄infrared  191   a.  Therefore, in these three cases, the initial position detection pin  189  has to be located in a reference position detected by the initial position detection switch  190  at least once. The turret  151  rotates in the α direction (forward rotation) and in the β direction (backward rotation) as shown in  FIG. 23 . The turret  151  realizes the above ‘a’ and ‘b’ by rotating in the α direction (forward rotation) and the above ‘c’ by rotating in the β direction (backward rotation), and has a filter arrangement in which each of the switching speeds can be enhanced fastest to the maximum.  
         [0264]     As shown in  FIG. 24 , the neutral density mesh turret  152  comprises four neutral density mesh filters  192   a - 192   d.    
         [0265]     As an example, these neutral density mesh filters  192   a - 192   d  are arranged so that the transmission (porosity) becomes higher from left to right, and is set in the following order of transmission: 50%, 65%, 75% and 100% (no mesh).  
         [0266]     In the light source device  103  of the present embodiment, when the light source connectors  124   a,    124   c,  and  124   d  of the endoscope  102  (the normal flexible endoscope  111 , the normal rigid endoscope  113 , and the high-brightness rigid endoscope  114 ) are pulled out from the connector receiver unit  141 , or when initializing, the turret  152  is set to the initial position so that the neutral density mesh filter  192   a  with a transmission of 50% is set on the optical path.  
         [0267]     It should be noted that even if the turret stops at a non-transmissive part other than the neutral density mesh filters  192   a - 192   d  for some reason, the neutral density mesh turret may have the configuration shown in  FIG. 25  so that the light is not shielded.  
         [0268]      FIG. 25  is a front view of the neutral density mesh turret showing example ( 1 ) of a variation of  FIG. 24 . As shown in  FIG. 25 , the neutral density mesh turret  152 B forms small holes for optical transmission  193 . It is possible to prevent complete shielding of the illuminating light supplied to the endoscope  102  via these small holes for optical transmission  193 .  
         [0269]     In addition, the neutral density mesh turret  152  is configured so as to be able to rotate under the power of the motor  159   b;  however, a slide neutral density mesh  152 C may be used as shown in  FIG. 26 .  
         [0270]      FIG. 26  is a front view of the neutral density mesh turret showing example (2) of a variation of  FIG. 24 . The slide neutral density mesh  152 C is formed in an approximate rectangle. The slide neutral density mesh  152 C can be driven in parallel by linear driving of the motor.  
         [0271]     By moving in parallel via linear driving, the neutral density mesh turret  152 C can have a configuration similar to that of the turret moving in rotation using a motor.  
         [0272]     Next, further aspects of the configuration of the neutral density mesh turret  152  are explained in detail.  
         [0273]      FIG. 27  is a perspective view showing in detail the configuration of the neutral density mesh turret of  FIG. 24 .  FIG. 28  is a perspective view showing an example of a modification in the attachment of the neutral density mesh of  FIG. 27 .  FIG. 29  is a perspective view showing the back of the neutral density mesh turret of  FIG. 28 .  
         [0274]     As shown in  FIGS. 27-29 , the neutral density mesh turret  152  is configured by attaching the trapezoid-shaped neutral density mesh filters  192   a - 192   d  to a hole unit  194  formed by having four holes linked together in a row on a turret board  152   a.    
         [0275]     The neutral density mesh filters  192   a - 192   d  have weaved wires such as metallic material wires with a thin wire diameter, and are formed in a single layer or multiple layers. The neutral density mesh filters  192   a - 192   d  are attached to a hole  194  (on one side or both sides). The neutral density mesh filters  192   a - 192   d  are formed to have transmissions of 50%, 65%, 75%, 100% (no mesh), respectively, as explained in an example above, in accordance with the hole  194 .  
         [0276]     In  FIG. 28  and  FIG. 29 , the neutral density mesh filters  192   a - 192   d  are attached to both sides of the hole  194  with no space left between. With this configuration, it is possible to prevent the mesh from misaligning for some reason, which cannot be done with the mesh filters attached on only one side as in  FIG. 27 . Thus, the maximum light intensity cannot be above the setting even if a space is generated between the meshes. Additionally, it is possible to attach the meshes so that the adjacent meshes overlap each other, further preventing unintended light leakage. Furthermore, the mesh filters are made so as to be processed easily, and therefore the adjacent meshes can be attached in a configuration in which they overlap each other.  
         [0277]     As explained later, combinations of the neutral density mesh filters  192   a - 192   d  and the observation filters  191   a - 191   d  are determined by the combination of the endoscope  102  (the normal flexible endoscope  111  in which two types of maximum light intensity can be set, the normal rigid endoscope  113 , or the high-brightness endoscope  114 ) and the observation mode (normal observation, narrowband observation, infrared observation, or narrowband/infrared normal observation).  
         [0278]     First, detection of the endoscope type is explained.  
         [0279]     The light source device  103  detects the endoscope type via the endoscope connection detection sensor  146  when one of the light source connectors  124 ,  124   c  and  124   d  of the endoscope  102  (the normal flexible endoscope  111 , the normal rigid endoscope  113 , or the high-brightness rigid endoscope  114 ) are selectively connected to the connector receiver unit  141 .  
         [0280]     Here, the endoscope  102  (the normal flexible endoscope  111 , the normal rigid endoscope  113 , or the high-brightness rigid endoscope  114 ) comprises the light source connectors  124   a,    124   c,  and  124   d,  as shown in  FIG. 30 .  
         [0281]      FIG. 30  is an overview explanatory diagram showing the relative positions in a state in which the connector of the endoscope of  FIG. 15  is connected to the light source. A light guide end  195 , which is an input end face of the light guide  131   a,  and an air-supply end  196  of the air-supply channel  131   c  are extended from the light source connector  124   a  of the normal flexible endoscope  111 .  
         [0282]     On the other hand, the light guide end  195  alone is extended from both the normal rigid endoscope  113  and the high-brightness rigid endoscope  114 .  
         [0283]     In the light source connector  124   d  of the high-brightness rigid endoscope  114 , the light guide end  195  is provided with a protrusion  197 . Because of the protrusion, the endoscope connection detection sensor  146  can detect the difference between the normal rigid endoscope  113  and the high-brightness rigid endoscope  114  as explained above.  
         [0284]     Note that the use of a high-brightness flexible endoscope is also possible. In such a case, a groove is formed, as shown by the broken line of  FIG. 30 , on the distal end connector  124   a  of the normal flexible endoscope at a position in which an advance/withdraw member  204  of  FIG. 31  etc. is pushed in, explained later. When this occurs, the distal end connector  124   a  can be pushed in only to the same position as the high-brightness rigid endoscope. Such a configuration can be easily obtained.  
         [0285]     Next, the configuration of the endoscope connection detection sensor  146  is explained in detail.  
         [0286]      FIG. 31  is a perspective view showing the surroundings of the connector receiver unit of  FIG. 22 .  FIG. 32  is a cross-sectional view of the surroundings of the connector receiver unit of  FIG. 31 . The endoscope connection detection sensor  146  is attached to the connector receiver unit  141 .  
         [0287]     The endoscope connection detection sensor  146  comprises three sensors, the first through third photosensors  201   a - 201   c.    
         [0288]     The first photosensor  201   a  and the second photosensor  201   b  are carried in the first fixing member  202  and are set in the direction of the insertion axis of the connector. The third photosensor  201   c  is carried in the second fixing member  203  and is set in a direction different from that of the first photosensor  201   a  and the second photosensor  201   c.  Note that the first fixing member  202  and the second fixing member  203  may be one.  
         [0289]     The connector receiver unit  141  is provided with an advance/withdraw member  204  which is held on by a holding member  204   a  that advances and withdraws by being pushed by the distal end when the endoscope of one of the light source connectors  124   a,    124   c  and  124   d  to be connected is inserted.  
         [0290]     The advance/withdraw member  204  comprises a first protrusion  205   a  and a second protrusion  205   b,  which can pass through the first photosensor  201   a  and the second photosensor  201   b,  respectively. A flexible member (made of an elastic material such as leaf spring)  206  is extended from the distal end side of the advance/withdraw member  204 . The ends of the flexible member  206  are provided with a third protrusion  205   c,  which can pass through the third photosensor  201   c  at the insertion of the light guide end  195  when it is pushed by the light guide end  195 .  
         [0291]     In this example, the first through third photosensors  201   a - 201   c  define the state where the light is not shielded as 1 (ON) and the state where the light is shielded by the first through third protrusions  205   a - 205   c  as 0 (OFF).  
         [0292]     In a state in which the light source connectors  124   a,    124   c,  and  124   d  shown in  FIG. 30  are not connected to the connector receiver unit  141 , the state is “1” in the first photosensor  201   a  and the second photosensor  201   b  since the light is not shielded by the first protrusion  205   a  and the second protrusion  205   b,  and the state is “0” in the third photosensor  201   c  since the light is shielded by the third protrusion  205   c.  In other words, the first through third photosensors  201   a - 201   c  are (1, 1, 0) (see  FIG. 36  and  FIG. 39 ).  
         [0293]     The light source connectors  124   a,    124   c,  and  124   d  of the endoscope  102  (the normal flexible endoscope  111 , the normal rigid endoscope  113 , the high-brightness rigid endoscope  114 ) are in the states shown in  FIG. 33 ,  FIG. 34 , and  FIG. 35  when being inserted into the connector receiver unit  141 .The different possible relations between the first through third photosensors  201   a - 201   c  and the first through third protrusions  205   a - 205   c  are the states shown in  FIGS. 36-40 .  
         [0294]     Further details are explained.  
         [0295]      FIG. 33  is a cross-sectional view of the connection of the light source of the normal flexible endoscope to the connector receiver unit of  FIG. 32 . As shown in  FIG. 33 , the light source connector  124 a of the normal flexible endoscope  111  is inserted into the connector receiver unit  141 . When this happens, the first photosensor  201   a  and the second photosensor  201   b  shift from the state shown in  FIG. 36  to the state shown in  FIG. 38 .  
         [0296]      FIG. 36  is an overview explanatory diagram showing the relationship between the first and second photosensors and the first and the second protrusions in  FIG. 32 .  FIG. 38  is an overview explanatory diagram showing the relationship between the first and second photosensors and the first and the second protrusions in  FIG. 34 . As shown in  FIG. 38 , the first photosensor  201   a  is OFF since the light is shielded by the first protrusion  205   a.  On the other hand, the second photosensor  201   b  is ON since the light is not shielded by the second protrusion  205   b.    
         [0297]     The state of the third photosensor  201   c  shifts from the state shown in  FIG. 39  to the state shown in  FIG. 40 .  
         [0298]      FIG. 39  is an overview explanatory diagram showing the relation between the third photosensor and the third protrusion in the state in which the third photosensor is OFF.  FIG. 40  is an overview explanatory diagram showing the relation between the third photosensor and the third protrusion in the state in which the third photosensor is ON. As shown in  FIG. 40 , the third photosensor  201   c  is ON since it is in a state in which the third protrusion  205   c  is moved by the distal end of the light guide end  195  and the light is not shielded.  
         [0299]     Then, in the first through third photosensors  201   a - 201   c,  when the light source connector  124   a  of the normal flexible endoscope  111  is connected to the connector receiver unit  141 , the state changes from the unconnected (1, 1, 0) to (0, 1, 1).  
         [0300]      FIG. 34  is a cross-sectional view of a case in which the light source connector of the high-brightness rigid endoscope is connected to the connector receiver unit of  FIG. 32 . As shown in  FIG. 34 , the light source connector  124   d  of the high-brightness rigid endoscope  114  is inserted into the connector receiver unit  141 . At that time, the states of the first photosensor  201   a  and the second photosensor  201   b  shift from the state shown in  FIG. 36  to the state shown in  FIG. 37 .  
         [0301]      FIG. 37  is an overview explanatory diagram showing the relationship between the first and second photosensors and the first and second protrusions in  FIG. 33 . As shown in  FIG. 37 , since the light is not shielded, the first photosensor  201   a  is ON, and since the light is shielded by the second protrusion  205   b,  the second photosensor  210   b  is OFF.  
         [0302]     The third photosensor  201   c  shifts its state from the state shown in  FIG. 39  to the state shown in  FIG. 40 , in the same manner as with the insertion of the normal flexible endoscope  111 , and becomes ON since the light is not shielded.  
         [0303]     Then, for the first through third photosensors  201   a - 201   c,  when the light source connector  124   d  of the high-brightness rigid endoscope  114  is connected to the connector receiver unit  141 , the state changes from the unconnected (1, 1, 0) to (1, 0, 1).  
         [0304]      FIG. 35  is a cross-sectional view of a case in which the light source connector of the normal rigid endoscope is connected to the connector receiver unit of  FIG. 32 . As shown in  FIG. 35 , the light source connector  124   c  of the normal rigid endoscope  113  is inserted into the connector receiver unit  141 . When that happens, since the advance/withdraw member  204  is not pushed and parallel movement does not occur, the first photosensor  201   a  and the second photosensor  201   b  are in the same state as the unconnected state shown in  FIG. 36 , and since the light is not shielded, both of the sensors are ON.  
         [0305]     The third photosensor  201   c  shifts from the state shown in  FIG. 39  to the state shown in  FIG. 40  in the same manner as the insertion of the normal flexible endoscope  111 , and since the light is shielded, the sensor is ON.  
         [0306]     Then, the state changes from the unconnected (1, 1, 0) to (1, 1, 1) in the first through third photosensors  201   a - 201   c  when the light source connector  124   c  of the normal rigid endoscope  113  is connected to the connector receiver unit  141 .  
         [0307]     The states of the first through third photosensors  201   a - 201   c  are summarized in Table 1.  
                                     TABLE 1                           First   Second   Third           photosensor   photosensor   photosensor       Type   (101a)   (101b)   (101c)                   Normal flexible   0   1   1       endoscope       Normal rigid   1   1   1       endoscope       High-brightness   1   0   1       rigid endoscope       Unconnected   1   1   0            Error   Other than the above                  
 
         [0308]     Note that the last row of Table 1 is for the case of error. In such a case, the first through third photosensors  201   a - 201   c  exhibit a combination other than the above combinations.  
         [0309]     With the above combinations, the light source device  3  can determine the connection state in the connector receiver unit  141  and can determine the type of connected endoscope  102  (the normal flexible endoscope  111 , the normal rigid endoscope  113 , or the high-brightness rigid endoscope  114 ).  
         [0310]     Accordingly, the light source device  103  can set the position of the mesh of the mesh turret, which determines each maximum allowable light intensity, on the basis of connection state D (explained later) in the connector receiver unit  141 . Additionally, it is possible to automatically set the other settings.  
         [0311]     Examples of the settings are described in Table 2. The settings in Table 2 are stored in advance as setting information in the FRAM  162 .  
                       TABLE 2                               Initial       Setting item   Setting contents   setting                   Normal flexible   Automatic/manual light   Automatic       endoscope   adjustment (set at startup)       connection   Brightness level (set at startup)   Median value       setting   Automatic/manual light   Manual       D = 0   adjustment (set at           automatic/manual setting)           Brightness level (set at   Minimum value           automatic/manual setting)           Pump ON/OFF   ON           Pump level   Maximum value           High-brightness OFF (internal   —           operation, display off)       Normal rigid   Automatic/manual light   Automatic       endoscope   adjustment (set at startup)       connection   Brightness level (set at startup)   Median value       setting   Automatic/manual light   Manual       D = 2   adjustment (set at           automatic/manual setting)           Brightness level (set at   Minimum value           automatic/manual setting)           Pump (internal operation OFF,   —           display off)           Pump level (display off)   —           High-brightness OFF (internal   —           operation, display off)       High-brightness   Automatic/manual light   Automatic       rigid endoscope   adjustment (set at startup)       connection   Brightness level (set at startup)   Median value       setting   Automatic/manual light   Manual       D = 3   adjustment (set at           automatic/manual setting)           Brightness level (set at   Minimum value           automatic/manual setting)           Pump (internal operation OFF,   —           display off)           Pump level (display off)   —           High-brightness OFF/OFF   ON       Unconnected   Setting display information of   Initial       setting   flexible/rigid endoscope   setting is D = 0       D = 4   immediately before being           disconnected           Pump (internal operation OFF)   —           Diaphragm fixing (internal   —           operation)       Connection   Normal flexible endoscope   —       detection error   connection setting       setting       D = 5                  
 
         [0312]     Note that the normal flexible endoscope  11 , since the air-supply channel  131   c  is provided as described above, can supply air via the pump  153  of the light source device  3 . On the other hand, the normal rigid endoscope  113  and the high-brightness rigid endoscope  114  do not use the pump  153 .  
         [0313]     In addition, the illuminating switches and display of the operation panel may be turned on/off in accordance with these setting items.  
         [0314]     Based on the combination type of observation mode (normal observation, narrowband observation, infrared observation, or narrowband/ infrared normal observation) and type of endoscope  102  (normal flexible endoscope  111 , normal rigid endoscope  113 , or high-brightness rigid endoscope  114 ), the combination of neutral density mesh filters  192   a - 192   d  and observation filters  191   a - 191   e  is determined as shown in Table 3.  
                                                                               TABLE 3                                       Observation   Neutral           mode   density           switching   mesh           turret   turret            Connected           Trans-       Trans-       endoscope   Observation   Filter   Mission   Mesh   mission       type   mode   type   (%)   type   (%)                    Normal   Normal   Normal   85   Neutral   65       flexible   observation   observation       density       endoscope   1   light       mesh 2               transmission               filter       Normal   Normal   Normal   85   Neutral   75       flexible   observation   observation       density       endoscope   2   light       mesh 3               transmission               filter       Normal   Special   Special   50   Neutral   100       flexible   light   observation       density       endoscope   observation   light       mesh 4           1   transmission               filter 4       Normal/   Special   Special   60   Neutral   100       high-   light   observation       density       brightness   observation   light       mesh 4       rigid   2   transmission       endoscope       filter 3       Normal/   Special   Special   75   Neutral   100       high-   light   observation       density       brightness   observation   light       mesh 4       rigid   3   transmission       endoscope       filter 1       Normal/   Special   Special   65   Neutral   100       high-   light   observation       density       Brightness   observation   light       mesh 4       rigid   4   transmission       endoscope       filter 2       Normal/   Normal   Normal   85   Neutral   50       high-   observation   observation       density       Brightness   3   light       mesh 1       rigid       transmission       Endoscope       filter       High-   High-   Normal   85   Neutral   100       brightness   brightness   observation       density       rigid   normal   light       mesh 4       endoscope   observation   transmission           1   filter       Flexible   Abnormal   Emergency   —   Neutral   100       endoscope/   observation   lighting:   (no   density       rigid       halogen   trans-   mesh 4       endoscope       lamp   mission)       Unconnected   Unconnected   Filter   Depends   Neutral   50               used   on filter   density               immediately   used   mesh 1               before being   immedi-               disconnected   ately                   before                   being                   discon-                   nected                  
 
         [0315]     In a case in which the light input into the endoscope  102  is lamp light with an intensity of 100, the high-brightness light intensity is, for example, 100 (lamp light intensity)×0.85 (85% transmission of the observation mode switching turret  151 )×1 (100% transmission of the neutral density mesh turret  52 )=85.  
         [0316]     In the light source device  103  with the above configuration, one of the light source connectors  124   a,    124   c,  or  124   d  of the endoscope  102  (the normal flexible endoscope  11 , the normal rigid endoscope  113 , or the high-brightness rigid endoscope  114 ) is selectively connected in a detachable manner, as shown in  FIG. 15 , and is used for endoscopic examination.  
         [0317]     A user turns on the power, starts the light source device  103 , and conducts the endoscopic examination.  
         [0318]     If the automatic/manual lighting switching switch  155  is set to automatic, the MPU  161  controls the lamp lighting control unit  168  by a detection signal from the automatic/manual lighting switching control unit  173  (which received a signal from the automatic/manual lighting switching switch  155 ) so that the xenon lamp  142  lights at the startup time when the power switch is turned ON.  
         [0319]     In contrast, when the automatic/manual lighting switching switch  155  is set to manual, the MPU  161  controls the lamp lighting control unit  168  so that the xenon lamp  142  lights when the lamp ON/OFF switch  187   a  of the operation panel  182  is held down after startup when the power switch is turned ON.  
         [0320]     When that happens, the MPU  161  of the light source device  103  controls each unit in the device by controlling each unit of the control board  145  in a manner following the main flowchart shown in  FIG. 41 .  
         [0321]      FIG. 41  is a flowchart showing the operation of the MPU. In the MPU  161 , the initial setting is performed (step S 2 ) when the power of the light source device  103  is turned ON by turning on the power switch  181  (step Si).  
         [0322]     In addition, the MPU  161  starts a 100 ms count with a 100 ms timer (step S 3 ).  
         [0323]     In the following description, the MPU  161  assigns a connection state D, which is the current connection detection result, to a connection state judge buffer SJ for every 100 ms. For the MPU  161 , the connection state is determined to be the connection state D if the connection state judge buffer SJ(D) does not change for 200 ms (until removal of noise or chattering). Note that the connection judge buffer SJ is provided in the FRAM  162 .  
         [0324]     First, the MPU  161  assigns 0 to a connection judge time counter t (step S 4 ). Next, the MPU  16  determines the connection state D in the connector receiver unit  141  detected by the endoscope connection detection unit  166  (step S 5 ). Note that the connection judge time counter t represents an elapsed time of 100 ms when t=1 and an elapsed time of 200 ms when t=2.  
         [0325]     Here, on the basis of an ON/OFF signal input from the endoscope connection detection sensor  146  (the first through third photosensors  201   a - 201   c ), the endoscope connection detection unit  166  obtains one of five values, from 1 to 5 shown below, as the connection state D, as described in Table 1. 
    Connection state D=0: when the normal flexible endoscope  111  is connected     Connection state D=2: when the normal rigid endoscope  113  is connected     Connection state D=3: when the high-brightness rigid endoscope  114  is connected     Connection state D=4: when no endoscope is connected     Connection state D=5: when an error is generated    
 
         [0331]     Next, the MPU  161  determines whether the connection determination time counter t is at a value other than 0 (step S 6 ).  
         [0332]     When the connection determination time counter t is at a value other than 0, the MPU  161  determines whether or not the connection state judge buffer SJ is in connection state D (step S 7 ).  
         [0333]     When the connection state judge buffer SJ is the connection state D, the MPU  161  proceeds to the next step.  
         [0334]     When the connection state judge buffer SJ is not in the connection state D, the MPU  161  assigns 0 to the connection determination time counter t (step S 8 ) and proceeds to the next step.  
         [0335]     Next, the MPU  161  assigns the connection state D to the connection state judge buffer SJ (Step S 9 ).  
         [0336]     Next, the MPU  161  determines whether or not  100  ms has elapsed (step S 10 ).  
         [0337]     The MPU  161  repeats S 10  until 100 ms has elapsed.  
         [0338]     Next, the MPU  161  determines whether or not the connection determination time counter t has become t=2 (step S 11 ).  
         [0339]     When the connection determination time counter t is not t=2, the MPU  161  assigns t+1 to the connection determination time counter t (step S 12 ) and repeats S 5 -S 12 .  
         [0340]     When the connection determination time counter t is t=2, the MPU  161  determines that the connection state of the endoscope  102  is D (step S 13 ). In such a case, the MPU  161  reads out setting information of the connection state D from the FRAM  162  and performs operation setting of the light source (Step S 14 ).  
         [0341]     Here, the setting information of the connection state D has the settings shown in Table 2, and the setting of the light source device  103  is conducted in accordance with these settings.  
         [0342]     The MPU  161  starts the normal operation of the light source device  103  (step S 15 ).  
         [0343]     A user holds down the filter mode switch  188   a  of the illumination mode setting display unit  188 , and selects the special light observation mode displayed in the special light observation display unit  188   b.    
         [0344]     The light source device  103 , based on the selected special light observation mode, controls each unit in the device via the MPU  161  controlling each unit on the control board  145 .  
         [0345]     Here, the MPU  161  controls the observation mode switching turret control unit  163  so that the observation filter from among the observation filters  191   a - 191   e  that corresponds to the selected observation mode is set on the optical path. The MPU  161  also controls and drives the motor  159   a.    
         [0346]     At the same time, the MPU  161  controls the neutral density mesh turret control unit  164  so that the neutral density mesh filter from among the neutral density mesh filters  192   a - 192   d  that corresponds to the selected observation mode is set on the optical path. The MPU  161  also controls and drives the motor  159   b.    
         [0347]     The MPU  161  controls the diaphragm control unit  165  so that the diaphragm  149  limits the light intensity of the illuminating light in accordance with the selected observation mode and controls and drives the motor  159   c.    
         [0348]     There is a case in which a user, during the endoscopic examination, removes the high-brightness rigid endoscope  114  from the light source device  103  and connects a normal rigid endoscope  113  to the light source device  103  for a particular use.  
         [0349]     In such a case, during the high-brightness mode, the light source connector  124   d  of the high-brightness rigid endoscope  114  is pulled out of the connector receiver unit  141  and the light source connector  124   c  of the normal rigid endoscope  113  is newly connected to the connector receiver unit  141 .  
         [0350]     At that time, high-brightness illuminating light must not be supplied to the normal rigid endoscope  113  from the light source device  103 .  
         [0351]     For that reason, when the light source connector  124   d  of the high-brightness rigid endoscope  114  is ejected from the connector receiver unit  114  while in high-brightness mode, the light source device  103  sets the maximum of the light intensity of the illuminating light to be low. The same is set when the connection is changed from the high-brightness rigid endoscope  114  to the normal flexible endoscope  111 .  
         [0352]     The MPU  161  prevents high-brightness light intensity from being supplied to the normal endoscope  111  by the combination of the observation filters  191   a - 191   e  of the observation mode switching turret  151  and the neutral density mesh filters  192   a - 192   d  of the neutral density mesh turret  52 , as described in Table 3.  
         [0353]     Here, the endoscope connection detection unit  166  changes the detection time of the ON/OFF signal detected by the endoscope connection detection sensor  201   a - 201   c  on the bases of whether or the light source connectors ( 124   a,    124   c  or  124   d ) are connected to the connector receiver unit  141 .  
         [0354]     In other words, the endoscope connection detection unit  166  detects the endoscope  102  with a longer ON/OFF signal detection time detected by the endoscope connection detection sensor  201   a - 201   c  when the light source connector ( 124   a,    124   c,  or  124   d ) is connected to the connector receiver unit  141 .  
         [0355]     On the other hand, the endoscope connection detection unit  166  shortens the detection time of the ON/OFF signal detected by the endoscope connection detection sensor  201   a - 201   c  when the light source connector ( 124   a,    124   c  or  124   d ) is ejected from the connector receiver unit  141 , and immediately changes the setting of the light source device  103  to the unconnected setting. At that time, in addition, the diaphragm  149 , as explained above, is controlled to be half open.  
         [0356]     Here, the MPU  161  of the light source device  103  controls each unit in the device by controlling each unit of the control board  145  in accordance with the endoscope switching control flowchart shown in  FIG. 42 .  
         [0357]      FIG. 42  is a flowchart of an endoscope switching control operation performed by the MPU. As shown in  FIG. 42 , the MPU  161  determines whether, from normal operation (step S 15   a ), 100 ms has elapsed or not (step S 16 ).  
         [0358]     The MPU  161  repeats S 16  until 100 ms has elapsed.  
         [0359]     Next, the MPU  161  determines the connection state D detected by the endoscope connection detection unit  166  in the same manner as S 5  (step S 17 ).  
         [0360]     Next, the MPU  161  determines whether or not the connection state judge buffer SJ is in the connection state D (step S 18 ).  
         [0361]     In step S 18 , if the connection state judge buffer SJ is not in the connection state D, the MPU  161  assigns D to the connection state judge buffer SJ (step S 19 ). The connection determination time counter t is assigned the value 0 (step S 20 ), and the operation returns to S 16 .  
         [0362]     In S 18 , if the connection state judge buffer SJ is in the connection state D, the MPU  161  determines whether or not the connection determination time counter t is 0 (step S 21 ).  
         [0363]     In S 21 , if the connection determination time counter t is 0, the MPU  161  assigns t+1 to the connection determination time counter t (step S 22 ), and the operation returns to S 16 .  
         [0364]     In S 21 , if the connection determination time counter t is not 0, the MPU  161  determines the connection state to be 0, 2, or 3 (step S 23 ).  
         [0365]     In S 23 , if the connection state D is either 0, 2, or 3, the MPU  161  determines whether or not the connection determination time counter t is 14 (step S 24 ).  
         [0366]     In step S 24 , if the connection determination time counter t is not  14 , the MPU  161  assigns t+1 to the connection determination time counter t (step S 22 ), and the operation returns to S 16 .  
         [0367]     In S 24 , if the connection determination time counter t is 14, the MPU  161  determines that the connection state of the endoscope  102  is D (step S 25 ), reads out the setting information of the connection state D from the FRAM  162 , and sets the operation of the light source (step S 26 ). Then, the MPU  161  returns to the normal operation of the light source device  103  (step S 27 ).  
         [0368]     In step S 23 , if the connection state D is not 0, 2, or 3, the MPU  161  determines whether or not the connection state D is 4 (step S 28 ).  
         [0369]     In S 2 , if the connection state D is 4, the MPU  116  determines whether or not the value of the connection determination time counter t is 1 (step S 29 ).  
         [0370]     In S 29 , if the value of the connection determination time counter t is not 1, the MPU  161  assigns the value t+1 to the connection determination time counter t (step S 22 ), and the operation returns to S 16 .  
         [0371]     In S 29 , if the value of the connection determination time counter t is 1, the MPU  161  determines that the connection state of the endoscope  102  is D (step S 25 ), reads out the setting information of the connection state D from the FRAM  162 , and performs operation setting of the light source (step S 26 ). Then, the MPU  161  returns to normal operation of the light source device  103  (step S 27 ).  
         [0372]     In S 28 , if the connection state D is not 4, the MPU  161  determines that the connection state D is 5 (step S 30 ). Next, it is determined whether the value of the connection determination time counter t is 4 (step S 31 ).  
         [0373]     In S 31 , if the value of the connection determination time counter t is not 4, the MPU  161  assigns t+1 to the connection determination time counter t (step S 22 ), and the operation returns to S 16 .  
         [0374]     In step S 31 , if the value of the connection determination time counter t is 4, the MPU  161  determines that the connection state of the endoscope  102  is D (step S 25 ). The MPU  161  reads out the setting information of the connection state D from the FRAM  162  and performs operation setting of the light source (step S 26 ). Then, the MPU  161  returns to the normal operation of the light source device  103  (step S 27 ).  
         [0375]     It is thus possible during endoscopic examination to set the settings in accordance with the connected endoscope  102  in the light source device  103  even if, for example, the endoscope  102  is changed and connected. Note that the setting values (t=0, 1, 4, 14 etc.) for determination of the counter value of the counter t explained in the above flowchart are not limited to those numbers; however, the value may be changed according to the setting environment.  
         [0376]     In a case in which the connection state D is 5, the MPU  161  is configured to set, while issuing an error notice, the connection setting of the normal rigid endoscope  113  so that the barebones examination can be continued.  
         [0377]     There is a case in which a user may change the settings of the light source device  103  via the operation panel  182  of the front panel  147  during the endoscopic examination. In such a case, the light source device  103 , in which the setting is changed via the MPU  161 , controls each unit in the device on the basis of the settings by controlling each unit of the control board  145 .  
         [0378]     Here, the MPU  161  of the light source device  103  writes the changed settings in the FRAM  162  in accordance with the memory write-in control flowchart shown in  FIG. 43 .  
         [0379]      FIG. 43  is a flowchart of a memory write-in control operated by the MPU. The MPU  161 , during normal operation (step S 15   a ), determines whether or not the setting is changed by a switch (SW) provided in the operation panel  182  of the front panel  147  (step S 32 ).  
         [0380]     The MPU  161  repeats S 32  until the setting is changed via the switch on the operation panel  182 .  
         [0381]     If the setting is changed via the switch on the operation panel  182 , the MPU  161  determines whether the connection state D is not 4 or 5 (step S 33 ).  
         [0382]     In S 33 , if the connection state D is not 4 or 5, the MPU  161  writes the changed settings in each memory area of the FRAM  162  corresponding to the current connection state D and in the memory area of the FRAM  162  corresponding to the connection state D=4 (step S 34 ), and the operation returns to S 32 .  
         [0383]     In S 33 , if the connection state D is 4 or 5, the MPU  161  determines whether or not the connection state D is 4 (step S 35 ).  
         [0384]     In S 35 , if the connection state D is 4, the MPU  161  writes the changed settings in each memory area of the FRAM  162  corresponding to the connection state D=4, and in the memory area of the FRAM  62  corresponding to the connection state D (0, 2, or 3) (step S 36 ), and the operation returns to S 32 .  
         [0385]     In S 35 , if the connection state D is not 4, the MPU  161  returns the operation to S 32 .  
         [0386]     By doing this, the light source device  103  can set each unit in the device according to the stored settings when starting up after the changed settings are stored in the FRAM  162 .  
         [0387]     There is a case in which a user, during endoscopic examination for example, may change the observation mode via the operation panel  182  of the front panel  147 .  
         [0388]     The user holds down the filter mode switch  188   a  of the illumination mode setting display unit  188  and selects the special light observation mode displayed in the special light observation display unit  188   b.    
         [0389]     The light source device  103 , based on the selected special light observation mode, controls each unit in the device via the control of each unit of the control board  145  by the MPU.  
         [0390]     The MPU  161  of the light source device  103  switches the observation mode in accordance with the observation mode switching control flowchart shown in  FIG. 44 .  
         [0391]      FIG. 44  is a flowchart of the observation mode switching control operated by the MPU. In the light source device  103 , an observation mode change request is generated by a switch (the filter mode switch  188   a  of the illumination mode setting display unit  188 ) provided on the operation panel  182  of the front panel  147  (step S 41 ).  
         [0392]     Then, the MPU  161  determines whether or not the transmission of the current observation switching turret  151  is greater than that of the neutral density mesh turret  152  (step S 42 ).  
         [0393]     In S 42 , if the transmission of the current observation switching turret  151  is greater than that of the neutral density mesh turret  52 , the MPU  161  starts switching of the observation mode switching turret  151  (step S 43 ).  
         [0394]     The MPU  161  controls the observation mode switching turret control unit  163  so that the observation filter from among the observation filters  191   a - 191   e  that corresponds to the selected observation mode is set on the optical path. The MPU  161  also controls and drives the motor  159   a.    
         [0395]     Then, the MPU  161  completes the switching of the observation mode switching turret  151  (step S 44 ).  
         [0396]     Next, the MPU  161  starts switching the neutral density mesh turret  152  (step S 45 ). The MPU  161  controls the neutral density mesh turret control unit  164  so that the neutral density mesh filter from among the neutral density mesh filters  192   a - 192   d  that corresponds to the selected observation mode is set on the optical path. The MPU  161  also controls and drives the motor  159   b.    
         [0397]     Then, the MPU  161  completes the switching of the neutral density mesh turret  152  (step S 46 ) and the observation mode change is completed (step S 47 ).  
         [0398]     In S 42 , if the transmission of the current observation mode switching turret  151  is smaller than that of the neutral density mesh turret  152 , the MPU  161  starts the switching of the neutral density mesh turret  152  (step S 48 ).  
         [0399]     The MPU  161  controls the neutral density mesh turret control unit  164  so that the neutral density mesh filter from among the neutral density mesh filters  192   a - 192   d  that corresponds to the selected observation mode is set on the optical path. The MPU  161  also controls and drives the motor  159   b.    
         [0400]     Then, the MPU  161  completes the switching of the neutral density mesh turret (step S 49 ).  
         [0401]     Next, the MPU  161  starts the switching of the observation mode switching turret  151  (step S 50 ).  
         [0402]     The MPU  161  controls the observation mode switching turret control unit  63  so that the observation filter from among the observation filters  191   a - 191   e  that corresponds to the selected observation mode is set on the optical path. The MPU  161  also controls and drives the motor  159   a.    
         [0403]     Then, the MPU  161  completes the switching of the observation mode switching turret  151  (step S 51 ) and the observation mode change is completed (step S 47 ).  
         [0404]     By doing this, the light source device  103  can automatically change the setting in accordance with the changed observation mode even if the observation mode is changed during the operation.  
         [0405]     It should be noted that the present invention is not limited to the embodiments described above; many modifications and variations can be made thereto without departing from the scope and gist of the inventions.  
         [0406]     The light source device for an endoscope in the present embodiment comprises an endoscope connection unit that can be selectively connected to a plurality of types of endoscopes, a light source for generating illuminating light supplied to an endoscope connected to the endoscope connection unit, an optical system guiding illuminating light generated from the light source to the endoscope, an observation filter turret comprising a plurality of types of observation filters for limiting the wavelength range of light from the light source in accordance with an observation mode of the endoscope and that is able to set an observation filter corresponding to the observation mode of the endoscope on an optical path of the optical system, and a neutral density filter turret comprising a plurality of types of neutral density filters for darkening light from the light source in accordance with an observation mode of the endoscope and that is able to set a neutral density filter corresponding to the endoscope on an optical path of the optical system.  
         [0407]     In the above light source for an endoscope, the neutral density filter on the neutral density filter turret is a neutral density mesh filter.  
         [0408]     In the above light source for an endoscope, the neutral density filter turret can rotate or can move in parallel so that the neutral density filter corresponding to the endoscope is set on an optical path of the optical system.  
         [0409]     The light source device for an endoscope in the present embodiment comprises an endoscope connection unit that can be selectively connected to a plurality of types of endoscopes, a detection sensor inside the endoscope connection unit for detecting the type of endoscope, a detection unit for detecting the type of the endoscope on the basis of a signal from the detection sensor, memory for storing settings in accordance with the type of endoscope, and a control unit for making an automatic setting in accordance with the settings stored in the memory on the basis of a detection result of the detection unit.  
         [0410]     In the above light source device for an endoscope, the detection unit changes the detection time when the endoscope is connected to the endoscope connection unit from the detection time when the endoscope is removed from the endoscope connection unit.  
         [0411]     In the light source device for an endoscope, also, the detection unit shortens the detection time when the endoscope is removed from the endoscope connection unit and changes the settings to the settings that exist when the endoscope is not connected.  
         [0412]     AS described above, the light source device of the present invention has an effect in which various optical filters, special light filters and neutral density mesh filters are provided, the device can be downsized. In addition, in the light source device for an endoscope of the present invention, it is possible to automatically change the setting in accordance with the type of endoscope connected.