Microscope system

Abstract

In a microscope system in which at least one of a stage on which a sample 4 is mounted and an objective lens 6 can move relatively in a direction of an optical axis, a contact judgment section 12 judges the possibility of contact between the sample 4 and the objective lens 6 based on a result of comparison between a detection output from a contact sensor 11 which detects contact between the sample 4 and the objective lens 6 and a preset threshold value, excessive contact between the sample 4 and the objective lens 6 is avoided based on a result of this judgment, and a threshold value in the contact judgment section 12 is updated based on the output from the contact sensor 11 every predetermined time.

What is claimed is:  
     
         1 . A microscope system in which an objective lens for observing an observation object can be relatively moved in a direction of an optical axis with respect to a stage on which said observation object is mounted, said microscope system comprising: 
 detecting means for detecting a contact state corresponding to non-contact and contact between said observation object and said objective lens and outputting a signal in accordance with said contact state;    judging means for judging that said contact state between said observation object and said objective lens has exceeded a predetermined value based on an output from said detecting means and outputting an excessive contact signal, said judging means including threshold value setting means for setting a threshold value which is a reference for judgment on contact and a comparator section for comparing said set threshold value with an output from said detecting means, said threshold value setting means resetting a threshold value based on an output from said detecting means in a state in which said observation object is separated from said objective lens; and    controlling means for controlling relative movement of said stage and said objective lens in response to said excessive contact signal.    
     
     
         2 . The microscope system according to  claim 1 , wherein said judging means includes state detecting means for generating a first separation state signal by detecting a first separation state that said observation object and said objective lens are separated from each other by a predetermined distance or more and generating a second separation state signal by detecting a second separation state that said objective lens is focusing on said observation objective lens, and 
 wherein said threshold value setting means resets a threshold value based on an output from said detecting means in response to one of said first and second separation state signals.    
     
     
         3 . The microscope system according to  claim 2 , wherein, when said first and second separation state signals are not generated for a predetermined period, said threshold value setting means returns said threshold value to a preset initial value after elapse of said period.  
     
     
         4 . The microscope system according to  claim 1 , wherein said detecting means includes a pressure sensor which detects a contact pressure corresponding to non-contact and contact between said observation object and said objective lens.  
     
     
         5 . The microscope system according to  claim 1 , wherein said detecting means includes an electrical capacitance sensor which detects an electrical capacitance corresponding to non-contact and contact between said observation object and said objective lens.  
     
     
         6 . The microscope system according to  claim 1 , wherein said objective lens has an end part opposed to said observation object and said electrical capacitance sensor is provided at said end part of said objective lens.  
     
     
         7 . The microscope system according to  claim 2 , wherein said detecting means includes a pressure sensor which detects a contact pressure corresponding to non-contact and contact between said observation object and said objective lens and said initial value is preset based on a thickness and conductivity of said sample in advance.  
     
     
         8 . A microscope system in which an objective lens for observing an observation object can be moved relatively in a direction of an optical axis with respect to a stage on which said observation object is mounted, said microscope system comprising: 
 detecting means for detecting a contact state corresponding to non-contact and contact between said observation object and said objective lens and outputting a signal in accordance with said contact state;    direct-current component eliminating means for eliminating a direct-current component from said detection signal outputted from said detecting means and generating a contact judgment signal;    judging means for judging that said contact state between said observation object and said objective lens has exceeded a predetermined value based on said contact judgment signal and outputting an excessive contact signal; and    controlling means for controlling relative movement of said stage and said objective lens in response to said excessive contact signal.    
     
     
         9 . The microscope system according to  claim 8 , wherein said direct-current component eliminating means includes a high-pass filter which eliminates a low-frequency component.  
     
     
         10 . The microscope system according to  claim 8 , wherein said direct-current component eliminating means has a band-pass filter which combines differential gain characteristics, proportional gain characteristics and integral gain characteristics and eliminates bands other than a predetermined frequency band.  
     
     
         11 . The microscope system according to  claim 8 , wherein said contact judging means includes a comparator which compares a contact judgment signal from said direct-current component eliminating means with a preset threshold value.  
     
     
         12 . The microscope system according to  claim 8 , wherein said detecting means includes a pressure sensor which detects a contact pressure corresponding to non-contact and contact between said observation object and said objective lens.  
     
     
         13 . The microscope system according to  claim 8 , wherein said detecting means includes an electrical capacitance sensor which detects an electrical capacitance corresponding to non-contact and contact between said observation object and said objective lens.  
     
     
         14 . The microscope system according to  claim 8 , wherein said objective lens has an end part opposed to said observation object and said electrical capacitance sensor is provided at said end part of said objective lens.  
     
     
         15 . The microscope system according to  claim 8 , wherein said detecting means includes a pressure sensor which detects a contact pressure corresponding to non-contact and contact between said observation object and said objective lens and said predetermined value is preset based on a thickness and conductivity of said sample.  
     
     
         16 . A microscope apparatus comprising: 
 a stage on which an observation object is mounted;    a plurality of objective lenses used for observing said observation object;    objective lens selecting means for selecting one objective lens from a plurality of said objective lenses and arranging said objective lens on an optical axis of a microscope;    moving means for relatively moving said selected objective lens with respect to said stage at a relative speed depending on said selected objective lens;    detection elements, provided at said objective lenses respectively, for detecting a contact state corresponding to non-contact and contact between said observation object and said selected objective lens depending on selection of said objective lens, and outputs a detection signal according to said contact state;    filtering means for generating a contact judgment signal obtained by eliminating a direct-current component from said detection signal;    judging means for judging that said contact state between said observation object and said objective lens has exceeded a predetermined value based on said contact judgment signal and outputting an excessive contact signal; and    controlling means for controlling relative movement of said stage and said objective lens in response to said excessive contact signal.    
     
     
         17 . The microscope system according to  claim 16 , wherein said direct-current component eliminating means includes a high-pass filter which eliminates a low-frequency component.  
     
     
         18 . The microscope system according to  claim 16 , wherein said direct-current component eliminating means has a band-pass filter which combines differential gain characteristics, proportional gain characteristics and integral gain characteristics and eliminates bands other than a predetermined frequency bands.  
     
     
         19 . The microscope system according to  claim 16 , wherein said contact judging means includes a comparator which compares a contact judgment signal from said direct-current component eliminating means with a preset threshold value.  
     
     
         20 . The microscope system according to  claim 16 , wherein said detection element includes a pressure sensor which detects a contact pressure corresponding to non-contact and contact between said observation object and said objective lens.  
     
     
         21 . The microscope system according to  claim 16 , wherein said detection element includes an electrical capacitance sensor which detects an electrical capacitance corresponding to non-contact and contact between said observation object and said objective lens.  
     
     
         22 . The microscope system according to  claim 16 , wherein said objective lens has an end part opposed to said observation object and said electrical capacitance sensor is provided at said end part of said objective lens.  
     
     
         23 . The microscope system according to  claim 16 , wherein said detection element includes a pressure sensor which detects a contact pressure corresponding to non-contact and contact between said observation object and said objective lens and said predetermined value is preset based on a thickness and conductivity of said sample.  
     
     
         24 . The microscope system according to  claim 16 , wherein said filtering means includes a band-pass filter which allows transmission of a detection signal in a frequency band of 50 Hz to 10 kHz and reduces any other signals.  
     
     
         25 . The microscope system according to  claim 24 , wherein said band-pass filter allows transmission of a detection signal in a frequency band of 500 Hz to 10 kHz and reduces any other signals.  
     
     
         26 . The microscope system according to  claim 24 , wherein said band-pass filter allows transmission of a detection signal in a frequency band of 50 Hz to 1 kHz and reduces any other signals.  
     
     
         27 . The microscope system according to  claim 23 , wherein, when said detection element has the sensitivity of S (V/μm) and said predetermined value is r (V), said band-pass filter allows transmission of a detection signal in a frequency band of S/20 r Hz to S/r Hz and reduces any other signals.  
     
     
         28 . The microscope system according to  claim 16 , wherein said filtering means includes a plurality of filters having filter characteristics corresponding to said respective objective lenses, and said detecting means includes switching means which selects one filter corresponding to said selected objective lens in dependence upon said selected objective lens, switches and supplies said detection signal to said selected filter.