Abstract:
In A confocal microscope, a mirror reflects illumination light to focus on a focal point face of a sample through an object lens. The mirror is rotated to scan a focal point of the illumination light. A confocal image provided based on returned light from the sample. The confocal microscope has a first multipinhole array which has a plurality of pinholes, and to which light emitted from a light source is illuminated, and a second multipinhole array which has a plurality of pinholes, and intercepts light from other than the focal point face out of the returned light from the sample. The first multipinhole array functions as a plurality of point light sources, and the illumination light is light which passes through the pinholes of the first multipinhole array.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is based upon and claims the benefit of priority from the prior Japanese Patent Applications No. 2004-293278, filed on Oct. 6, 2004, the entire contents of which are incorporated herein by reference.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to a confocal microscope, in details, relates to a confocal microscope which scans laser light by rotating a mirror to provide a confocal image of a sample.  
         [0004]     2. Description of the Related Art  
         [0005]     A confocal microscope is for observing a sample by acquiring an image by scanning a converged light point on the sample and focusing returned light from the sample and is used for observing a physiological reaction of a live cell or observing morphology thereof in a field of a living body, biotechnology or the like or observing a surface of LSI in a semiconductor market.  
         [0006]      FIG. 10  is a configuration view showing an example of a confocal microscope of a related art.  
         [0007]     In  FIG. 10 , a light source  1  emits illumination light  2  which is laser light. A light converging optical element  3  is a one-dimensional beam expander disposed on an optical path and combined with, for example, a cylindrical lens for converging the illumination light  2  on an opening of an illumination light slit  4 .  
         [0008]     The illumination light slit  4  provides the illumination light  2  immediately after passing the opening of its own with a slender linear spatial light amount distribution. An optical element  5  for branching a light path, a mirror  6 , and a double face mirror  7  successively reflect the illumination light  2  passing through the opening of the illumination light slit  4  and the reflected illumination light  2  is irradiated to a sample  9  to be observed by passing an object lens  8 .  
         [0009]     Although observation light  10  which is a fluorescent signal induced at inside of the sample  9  to be observed by the illumination light  2  tracks a reverse optical path (object lens  8 →double face mirror  7 →mirror  6 ) to return to the optical element  5  for branching the optical path, the observation light  10  is transmitted through the optical element  5  for branching the optical path by an optical property of the optical element  5  for branching the optical path without being reflected. The optical path branching optical element  5  is, for example, a dichroic mirror.  
         [0010]     The optical path branching optical element  5  transmits the observation light  10  by a spectroscopic characteristic thereof. An observation light slit  11  subjected the observation light  10  converged onto an opening of its own performs an optical filtering to achieve a confocal effect. Here, the confocal effect is an effect of intercepting light from other than a focal point face of the sample  9  to be observed.  
         [0011]     The observation light  10  passing through the observation light slit  11  is reflected by a mirror  12 , thereafter, reflected by a relay lens  13 , mirrors  14 ,  15  and the double face mirror  7  and is converged again on an image face  17 . The observation light converged onto the image face  17  is incident on the naked eye  19  of an observer by an ocular lens  18  to form a linear observed image on the retina.  
         [0012]     According to the configuration, by setting a rotating shaft of the double face mirror  7  in a direction orthogonal to any of an optical path between the double face mirror  7  and the mirror  6 , an optical path between the double face mirror  7  and the mirror  15  and a microscope observing optical path  16 , and rotating the double face mirror  7  in either of directions indicated by broken line arrow marks by constituting a rotational center by the rotating shaft, the illumination light can one-dimensionally scan on the sample  9  to be observed and at the same time, can form a two-dimensional observed image on the retina of the observer (refer to, for example, WO 92/17806 A1).  
         [0013]     WO 92/17806 A1 is referred to as a related art.  
         [0014]     According to the configuration, by deviating the double face mirror  7  from the optical path (by rotating the double face mirror  7  by constituting a rotational center by a pivot point  20 ), the normal microscope observing optical path  16  can newly be formed. Therefore, confocal observation and non-confocal observation can simply be switched to realize.  
         [0015]     However, since the slit is used as the optical filtering element for achieving the confocal effect in the above-described confocal microscope of the related art, optical filtering in a longitudinal direction of the slit does not function. Thereby, light from other than the focal point face cannot be intercepted with regard to a direction in correspondence with the longitudinal direction of the slit at inside of an observed image face. Therefore, the confocal effect cannot be achieved.  
       SUMMARY OF THE INVENTION  
       [0016]     An object of the invention is to provide a confocal microscope which enables to achieve a confocal effect with regard to all of directions at inside of an observed image face by using a multipinhole array as an optical filtering element for achieving the confocal effect.  
         [0017]     The invention provides the following confocal microscope.  
         [0018]     The invention provides a confocal microscope for reflecting illumination light by a mirror to focus on a focal point face of a sample through an object lens, rotating the mirror to scan a focal point of the illumination light, and providing a confocal image based on returned light from the sample, the confocal microscope having: a first multipinhole array which has a plurality of pinholes, and to which light emitted from a light source is illuminated; and a second multipinhole array which has a plurality of pinholes, and intercepts light from other than the focal point face out of the returned light from the sample, wherein the first multipinhole array functions as a plurality of point light sources, and the illumination light is light which passes through the pinholes of the first multipinhole array.  
         [0019]     The confocal microscope further has: a multilens array which is disposed on an optical path between the first multipinhole array and the light source, and has a plurality of microlenses which converge the light emitted from the light source, wherein multilens array is disposed at a position where each microlens corresponds to each pinhole of the first multipinhole array.  
         [0020]     In the confocal microscope, the mirror includes a reflector at a position where a rotation axis of the mirror is located.  
         [0021]     In the confocal microscope, the mirror is a polygonal mirror.  
         [0022]     The confocal microscope further has: a rotation sensor which outputs a rotational position signal indicating a rotational position of the mirror; and a control section which moves at least one of the object lens and a stage on which the sample is placed in an optical axis direction, in synchronization with rotation of the mirror, based on the rotational position signal.  
         [0023]     The confocal microscope further has: a control section which moves at least one of the object lens and a stage on which the sample is placed in an optical axis direction; a displacement sensor which outputs a displacement signal when at least one of the object lens and the stage is moved; and a mirror driving section which rotates the mirror in synchronization with a displacement between the object lens and the sample based on the displacement signal.  
         [0024]     The confocal microscope further has: a rotation sensor which outputs a rotational position signal indicating a rotational position of the mirror; and a camera which picks up the confocal image in synchronization with rotation of the mirror based on the rotational position signal.  
         [0025]     The confocal microscope further has: a control section which moves at least one of the object lens and a stage on which the sample is placed in an optical axis direction; a displacement sensor which outputs a displacement signal when at least one of the object lens and the stage is moved; and a camera which picks up the confocal image in synchronization with a displacement between the object lens and the sample based on the displacement signal.  
         [0026]     The confocal microscope further has: a camera which picks up the confocal image; and a mirror driving section which rotates the mirror in synchronization with an imaging by the camera based on a synchronization signal output from the camera.  
         [0027]     The confocal microscope further has: the camera which picks up the confocal image; and a control section which moves at least one of the object lens and a stage on which the sample is placed in an optical axis direction, in synchronization with an imaging by the camera, based on a synchronization signal output from the camera.  
         [0028]     The confocal microscope further has: a dichroic mirror which dividing the returned light; and a plurality of cameras which picks up each confocal image based on the returned light divided by the dichroic mirror.  
         [0029]     According to the confocal microscope, the following advantages are achieved.  
         [0030]     Since the confocal microscope has the first multipinhole array which functions the plurality of point light sources and the second multipinhole array as optical filtering elements, the confocal microscope can achieve the confocal effect with regard to all of directions within the observed image face.  
         [0031]     Since the confocal microscope has the microlenses for converging the laser light at the respective pinholes of the first multipinhole array, a transmittance of the laser light can be increased.  
         [0032]     Since the reflecting surfaces of the double face mirror for scanning the focal point of the observed sample coincide with the rotation axis of the double face mirror, a beam can be reflected by an always the same optical path.  
         [0033]     Since the polygonal mirror is used for the mirror which scans the focal point of the observed sample, a scanning speed can be increased.  
         [0034]     Since a scanning period by the double face mirror and a period of an actuator drive signal for controlling the distance between the object lens and the observed sample can be made to coincide with each other, the observed image without non-uniformity in scanning can be provided.  
         [0035]     Since an image taking period of the camera and a scanning period on the observed sample by the illumination light can be made to coincide with each other, the observed image without non-uniformity in scanning can be provided.  
         [0036]     Since the image taking period of the camera and the period of the actuator drive signal for controlling the distance between the object lens and the observed sample can be made to coincide with each other, the observed image without non-uniformity in scanning can be provided.  
         [0037]     Since the confocal microscope has the plurality of cameras which picks up each confocal image based on the returned light divided by the dichroic mirror, multicolor observation of the observed sample is realized. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0038]      FIG. 1  is a configuration view showing a first embodiment of a confocal microscope according to the invention;  
         [0039]      FIG. 2  is a view showing an example of a multipinhole array applied to the confocal microscope of the invention;  
         [0040]      FIG. 3  is a configuration view showing a second embodiment of the confocal microscope according to the invention;  
         [0041]      FIG. 4  is a view showing an example of a multimicrolens array applied to the confocal microscope of the invention;  
         [0042]      FIG. 5A  illustrates a view showing an example of a double face mirror applied to the confocal microscope of the related art, and  FIG. 5B  illustrates a view showing an example of a double face mirror applied to the confocal microscope of the invention;  
         [0043]      FIG. 6  is a configuration view showing a third embodiment of the confocal microscope according to the invention;  
         [0044]      FIG. 7  is a configuration view showing a fourth embodiment of the confocal microscope according to the invention;  
         [0045]      FIG. 8  is a configuration view showing a fifth embodiment of the confocal microscope according to the invention;  
         [0046]      FIG. 9  is a configuration view showing a sixth embodiment of the confocal microscope according to the invention; and  
         [0047]      FIG. 10  is a configuration view showing an example of a confocal microscope of a related art; 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0048]     Embodiments of the invention will be explained in details with reference to the drawings as follows.  
       First Embodiment  
       [0049]      FIG. 1  is a configuration view showing a first embodiment of a confocal microscope according to the invention. Constituent elements similar to those of the previous drawing are attached with similar notations, and an explanation of the portions will be omitted.  
         [0050]     The confocal microscope of the first embodiment shown in  FIG. 1  is different from the confocal microscope of the related art shown in  FIG. 10  in that an illumination light multipinhole array  22  substitutes for the illumination light slit  4 , an observation light multipinhole array  23  substitutes for the observation light slit  11 , and an optical element  21  for expanding light ray is disposed on an optical path between the illumination light multipinhole array  22  and the light source  1 .  
         [0051]     The optical element  21  for expanding light ray is a two-dimensional beam expander combined with, for example, a convex lens for enlarging a sectional area of light ray of the illumination light  2  emitted from the light source  1  to be incident on the illumination light multipinhole array  22 . As shown by  FIG. 2 , the illumination light multipinhole array  22  includes a plurality of pinholes and the illumination light  2  immediately after passing the pinholes  24  is regarded as light emitted respectively from point light sources. Here, the light source  1  is, for example, a laser light source.  
         [0052]      FIG. 2  is a view showing an example of a multipinhole array applied to the confocal microscope of the invention. By shifting the pinholes to align at predetermined intervals and aligning the pinholes obliquely to a scanning direction in this way, a density of the pinholes can be increased and a scanning stroke of the double face mirror  7  can be shortened.  
         [0053]     Referring back to  FIG. 1 , the illumination light  2  passing through an opening of the illumination light multipinhole array  22  is successively reflected by the optical element  5  for branching the optical path, the mirror  6 , the double face mirror  7  and thereafter irradiated to the observed sample  9  by transmitting through the object lens  8 . Although observation light  10  induced at inside of the observed sample  9  by the illumination light tracks the reverse optical path (object lens  8 →double face mirror  7 →mirror  6 ) to return to the optical element  5  for branching the optical path, the observation light  10  transmits through the optical element  5  for branching the optical path without being reflected by the optical property of the optical element  5  for branching the optical path and is converged onto the corresponding pinhole of the observation light multipinhole array  23 .  
         [0054]     The observation light multipinhole array  23  includes a plurality of pinholes. Each pinhole subjected incident light performs the optical filtering to achieve the confocal effect. The observation light  10  passing through the observation light multipinhole array  23  is reflected by the mirror  12 , thereafter, reflected by the relay lens  23  and the mirrors  14 ,  15 ,  7  and is converged again onto the image face  17 . The observation light  10  converged to the image face  17  is incident on the naked eye  19  of the observer by the ocular lens  18  to form an observed image (confocal image) of multispots on the retina.  
         [0055]     According to the configuration, by setting the rotating shaft of the double face mirror  7  in the direction orthogonal to any of the optical path between the double face mirror  7  and the mirror  6 , the optical path between the double face mirror  7  and the mirror  15  and the microscope observation light path  16  and rotating the double face mirror  7  in either of the directions indicated by the broken line arrow marks by constituting the rotational center by the rotating shaft, the illumination light of the multispots can one-dimensionally be scanned on the observed sample  9  and at the same time, the two-dimensional observed image can be formed on the retina of the observer. Further, the double face mirror  7  is rotated by a mirror driving section constituted by, for example, a DC motor and a driving apparatus for driving the motor (both of which are not illustrated).  
       Second Embodiment  
       [0056]      FIG. 3  is a configuration view showing a second embodiment of a confocal microscope according to the invention. Constituent elements similar to those of the previous drawings are attached with the similar notations, and an explanation thereof will be omitted.  
         [0057]     The confocal microscope of the second embodiment shown in  FIG. 3  is different from the confocal microscope of the first embodiment shown in  FIG. 1  in that a multimicrolens array  25  is disposed on an optical path between the light ray expanding optical element  21  and the illumination light multipinhole array  22 .  
         [0058]      FIG. 4  is a view showing an example of a multimicrolens array applied to the confocal microscope of the invention. As shown by  FIG. 4 , the multimicrolens array  25  includes microlenses at positions in correspondence with the pinholes of the illumination light multipinhole array  22  and the microlenses  26  converge the illumination light  2  onto the pinholes  24 . By converging the illumination light  2  onto the respective pinholes  24  of the illumination light multipinhole array  22  by the respective microlenses in this way, a transmittance of the illumination light  2  can be increased.  
         [0059]      FIG. 5A  illustrates a view showing an example of the double face mirror applied to the confocal microscope of the related art, whereas  FIG. 5B  illustrates a view showing an example of a double face mirror applied to the confocal microscope of the invention. In  FIG. 5A , the double face mirror  7  is constituted by, for example, a glass member having a predetermined thickness. The double face mirror  7  shown in  FIG. 5A  is constructed by a configuration of providing reflecting surfaces  71 ,  72  on both side faces of the glass member. In this case, the reflecting surfaces  71 ,  72  are shifted from a mirror rotating shaft  73 . Therefore, at each time of changing an angle of the double face mirror  7 , portions on which light ray is incident differ and also an optical path of reflected light ray is shifted. Therefore, it is necessary to separately provide correcting means for correcting the shift of the optical path.  
         [0060]     In contrast thereto, the double face mirror  70  shown in  FIG. 5B  is provided with a reflector  74  which is made to coincide with a mirror rotation axis  75  of the double face mirror  70  at inside of the glass member. When light ray is made to be incident on the rotation axis of the double face mirror  70 , even when the angle of rotating the double face mirror  70  is changed, portions on which light ray is incident on remain unchanged. Therefore, a beam can be reflected always on the same optical path and the above-described correcting means is not needed.  
       Third Embodiment  
       [0061]      FIG. 6  is a configuration view showing a third embodiment of the confocal microscope according to the invention. Constituent elements similar to those of the previous drawings are attached with similar notations, and an explanation of the portions will be omitted.  
         [0062]     The confocal microscope of the third embodiment in  FIG. 6  is different from the confocal microscope of the first embodiment shown in  FIG. 1  in that a polygonal mirror  27  substitutes for the double face mirror  7 , and optical path bending mirrors  28 ,  29  are provided for adjusting the optical path in accordance therewith.  
         [0063]     The polygonal mirror  27  is a polygonal prism having reflecting surfaces at side faces thereof. By rotating the polygonal prism around a center axis thereof, an angle of reflecting a beam incident on the side face is changed and a light converging point of a face of the observed sample is scanned. At the same time, the observation light  10  reflected from the mirror  15  is reflected by other side face. The optical path bending mirrors  28 ,  29  makes the observation light  10  reflected from the polygonal mirror  27  coincide with the microscope observing optical path  16 .  
         [0064]     When the polygonal mirror is used in this way, high speed scanning can be executed.  
       Fourth Embodiment  
       [0065]      FIG. 7  is a configuration view showing a fourth embodiment of the confocal microscope according to the invention. Constituent elements similar to those of the previous drawings are attached with similar notations, and an explanation of the portions will be omitted.  
         [0066]     The confocal microscope of the fourth embodiment shown in  FIG. 7  is different from the confocal microscope of the first embodiment shown in  FIG. 1  in the following. A camera  30  picks up the image of the observed sample  9  in place of the configuration of observing the observed sample  9  by the naked eye of the observer. A period of taking the image by the camera and a period of scanning by the double face mirror are made to coincide with each other.  
         [0067]     A camera  30  is disposed such that an image taking face of CCD coincides with the image face  17  to acquire an observed image of the observed sample  9 . A double face mirror driving circuit  31   a  makes the double face mirror  7  scan a focal point position of the illumination light  2  on the observed sample  9  by outputting a position control signal  32  and rotating the double face mirror  7  at a predetermined speed by a DC motor, not illustrated. The double face driving means  31   a  and the DC motor constitute a mirror driving section. Further, the double face mirror driving circuit  31   a  outputs a double face mirror rotational position signal  33  indicating a rotational position of the double face mirror  7  based on an output of a rotational sensor, not illustrated, (for example, a rotary encoder attached to the rotating shaft of the double face mirror  7 ) and the rotational position signal  33  is inputted to the camera  30  as a synchronization signal for determining the image taking period of the camera  30 .  
         [0068]     By the above-described, the image taking period of the camera  30  and the scanning period of the observed sample  9  by the illumination light  2  can be made to coincide with each other. Therefore, the observed image without non-uniformity in scanning can be provided.  
       Fifth Embodiment  
       [0069]      FIG. 8  is a configuration view showing a fifth embodiment of the confocal microscope according to the invention. Constituent elements similar to those of the previous drawings are attached with similar notations, and an explanation thereof will be omitted.  
         [0070]     The confocal microscope of the fifth embodiment shown in  FIG. 8  is different from the confocal microscope of the first embodiment shown in  FIG. 1  in that the camera  30  picks up slice images at respective positions in an optical axis direction of the observed sample  9  by reciprocating to move the object lens  8  along an optical axis direction, and a period of rotating the double face mirror  7  and the period of moving the object lens  8  in the optical axis direction are made to coincide with each other.  
         [0071]     A double face mirror driving circuit  31   b  makes the double face mirror scan the focal point position of the illumination light  2  on the observed sample  9  by outputting a position control signal  32  and rotating the double face mirror  7  at a predetermined speed by a DC motor, not illustrated. The double face mirror driving circuit  31   b  and the DC motor constitute a mirror driving section. Further, the double face mirror driving circuit  31   b  outputs the double face mirror rotational position signal  33  indicating the rotational position of the double face mirror  7  and the double face mirror rotational position signal  33  is inputted to an actuator driving circuit  35 .  
         [0072]     The actuator driving circuit  35  comprises, for example, an arbitrary waveform generator and an actuator driver, the arbitrary waveform generator outputs an analog waveform signal based on previously set waveform data, and the actuator driver outputs an actuator drive signal  37  in proportion to the analog waveform signal. The arbitrary waveform generator makes a scanning period by the double face mirror  7  and a period of an analog waveform constituting a basis of the actuator drive signal  37  coincide with each other based on the double face mirror rotational position signal  33 . An actuator  36  comprises, for example, a piezoelectric element for moving the object lens  8  in the optical axis direction in accordance with the actuator drive signal  37 .  
         [0073]     The actuator driving circuit  35 , the arbitrary waveform generator and the actuator driver constitute a control section for controlling a distance between the object lens and the observed sample  9 .  
         [0074]     By the above-described, the scanning period by the double face mirror  7  and the period of the actuator drive signal can be made to coincide with each other. Therefore, the observed image without non-uniformity in scanning can be provided.  
         [0075]     Further, although the embodiment is constructed by the configuration of moving the object lens  8 , a side of a stage (not illustrated) mounted with the observed sample  9  may be moved in the optical axis direction.  
         [0076]     Further, although not illustrated, the actuator  36  is provided with a displacement sensor and control of the position of the object lens  8  is carried out by feeding back an output of the displacement sensor to the actuator driving circuit  35 . Based on the output of the displacement sensor, a displacement signal indicating the distance between the object lens  8  and the observed sample  9  is outputted by the actuator driving circuit  35  and is inputted to the double face mirror driving circuit  31   b . The scanning period by the double face mirror and the period of the actuator drive signal may be made to coincide with each other by using the inputted displacement signal by the double face mirror driving circuit  31   b.    
         [0077]     Although similarly not illustrated, by combining the embodiment of  FIG. 7  and the embodiment, there may be constructed a configuration of making the image taking period of the camera  30 , the period of moving the object lens  8  and the scanning period by the double face mirror  7  coincide with each other.  
         [0078]     Further, a synchronization signal (for example, a vertical synchronization signal) of the camera may be inputted to the double face mirror driving circuit and the actuator driving circuit and the image taking period, the scanning period by the double face mirror and the actuator drive signal period may be made to coincide with each other based on the synchronization signal.  
       Sixth Embodiment  
       [0079]      FIG. 9  shows a configuration view showing a sixth embodiment of the confocal microscope according to the invention. Constituent elements similar to those of the previous drawings are attached with similar notations, and an explanation of the portions will be omitted.  
         [0080]     The confocal microscope of the sixth embodiment shown in  FIG. 9  is different from the confocal microscope of the first embodiment shown in  FIG. 1  in the following. Cameras  40 ,  41  pick up the image of the observed sample  9  in place of the configuration of observing the observed sample  9  by the naked eye of the observer. The observation light  10  from the observed sample  9  is divided the observation light by a dichroic mirror  39 , then each of cameras  40 ,  41  picks up the observed image based on the observation light divided by the dichroic mirror  39 .  
         [0081]     A relay lens  38  prolongs the microscope observation light path  16  and transmits the optical image of the image face  17  to the dichroic mirror  39 . The dichroic mirror  39  divides light of the transmitted optical image by a spectroscopic characteristic of its own, outputs the divided light to cameras  40 ,  41 . Then, each of the cameras  40 ,  41  pick up the observed images. Thereby, multicolor observation of the observed sample  9  is realized. Although according to the embodiment, the optical image is divided into spectra of 2 colors, for example, a color image can be acquired by taking and synthesizing the spectra optical images divided into spectra of R (red), G (green), B (blue).  
         [0082]     Further, the invention is not limited to the above-described embodiments but includes further numbers of changes and modifications within the range not deviated from the essence.