This application is based upon and claims the benefit of priority from the prior Japanese Patent Applications No. 2000-117739, Apr. 19, 2000; No. 2000-117740, Apr. 19, 2000; No. 2001-055815, Feb. 28, 2001; and No. 2001-110469 Apr. 9, 2001, the entire contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to a focus stabilizing apparatus for stabilizing a focused state of an optical apparatus, such as a microscope.
2. Description of the Background Art
Generally, a sample observation is carried out with the use of a microscope. This sample observation is made as follows. An observation sample is placed on a microscope stage and an objective lens is moved closer to the observation sample. By doing so, an observation spot of the observation sample is observed under a magnified state.
In this case, an objective lens has its focal depth decreased as the magnifying power becomes higher. It is, therefore, difficult to achieve a focus setting between the objective lens and the observation sample. Further, if the distance between the objective lens and the observation sample minutely varies, defocusing occurs between the focal point position of the objective lens and the observation sample due to a variation of the minute distance, so that the quality of the observation image is greatly degraded.
On the other hand, an apparent position between the objective lens and the observation sample is very closer to each other. By the way, there exists a mechanical coupling length between the objective lens and the observation sample. This mechanical coupling length is constituted by many mechanical component parts present between the objective lens and the observation sample. The mechanical coupling length is provided by the length over which, for example, a microscope frame, objective lens moving mechanism, objective lens mounting revolver are passed. Therefore, the length is very long because many mechanical components are interposed.
These mechanical component parts are liable to be varied in their dimensions due to a temperature variation involved.
Further, the greater the number of the mechanical component parts the greater the mechanical coupling length involved. The microscope is easily affected by a vibration and the vibration amplitude becomes greater.
If, therefore, the ambient temperature varies due to, for example, the turning ON/OFF of an illumination, internal power supply, etc., as well as the operation of an air conditioning equipment, then there arises a variation in the dimensions of mechanical component parts in the microscope. Even if, therefore, the focal setting of the objective is made relative to the observation sample, the distance between the objective lens and the observation sample greatly varies due to the above-mentioned dimensional variation and there occurs a defocusing.
Further, under a somewhat smaller external vibration, a greater vibration amplitude is involved and a distance between the objective lens and the sample varies, thus resulting in an out-of-focus state.
Heretofore, various kinds of autofocusing mechanisms have been considered to compensate such defocusing. These autofocusing mechanisms require a complex mechanical/electrical mechanism and control system. For this reason, the resultant apparatus becomes bulkier and expensive. Further, another microscope is known in which, like a fluorescent observation, the brightness is extremely darker at a time of observation. To such a microscope it is originally difficult to apply the above-mentioned autofocusing mechanism.
The following technique is disclosed in JPN PAT APPLN KOKAI Publication No. 9-120030. In this technique, a stage is provided through a rack and drive gears and it is driven in the optical axis direction of the objective lens. Between the gears and the stage, at least two rods are inserted. These rods are different in their thermal expansion coefficients and configured such that the direction of the thermal expansion coefficient of one rod acts in a direction opposite to that of the other rod. By doing so, defocusing is compensated.
In such a technique, the rods are arranged within the microscope body and a time is taken until the temperature is compensated under a variation of the ambient temperature. For this reason, there is a risk that, when the sample is observed, its operation, efficiency will be lowered. Further, since the rods are interposed, the mechanical coupling length becomes greater and its structure is liable to be affected from the external vibration. It is, therefore, necessary to remodel the microscope itself.
In the case where a living cell, etc., is observed as a target object, only a periphery side of the observation sample is sometimes warmed by a warmer. However, it is not possible to compensate a temperature drift involved.
It is accordingly the object of the present invention to provide a focus stabilizing apparatus which can make a focus setting of an objective lens relative to an observation sample under a stable way without being adversely influenced from a variation in the ambient temperature.
According to a main aspect of the present invention, a focus stabilizing apparatus is provided which comprises an objective lens arranged opposite to a observation sample, and position adjusting means provided at an outer periphery of the objective lens and adapted to move the observation sample in an optical axis direction to set a focal point of the objective lens to the observation sample.
According to a main aspect of the present invention, a focus stabilizing apparatus is provided which comprises an objective lens arranged opposite to the observation sample, a stage so provided as to be movable in a direction orthogonal to an optical axis of the objective lens, a sample base placed on the stage to retain the observation sample, position adjusting means provided at an outer periphery of the objective lens and adapted to move the observation sample in an optical axis direction through the sample base to set a focal point of the objective lens to the observation sample, and elastic means provided on the stage and so set through the sample base as to have a low rigidity in the optical axis direction of the objective lens and a high rigidity in a moving direction of the stage.
According to a main aspect of the present invention, a focus stabilizing apparatus is provided which comprises an objective lens arranged opposite to an objection lens, a stage so provided as to be movable in a direction orthogonal to an optical axis of the objective lens, a sample base placed on the stage to retain the observation sample, and position adjusting means provided at an outer periphery of the objective lens and adapted to move the observation sample in an optical axis direction of the objective lens through the sample base to set a focal point of the objective lens to the observation sample, wherein the position adjusting means has a fixing base for fixing the objective lens, a sample retaining base for placing the observation sample thereon, and an operation ring threadably inserted over the fixing base and, by being rotated relative to the fixing base, moving in the optical axis direction of the objective lens and moving the sample retaining base in the optical axis direction of the objective lens to adjust a relative distance between the observation sample and the objective lens.
According to a main aspect of the present invention, a focus stabilizing apparatus is provided which comprises an objective lens arranged opposite to an observation sample, a stage so provided as to be movable in a direction orthogonal to an optical axis of the objective lens, a sample base placed on the stage to retain the observation sample, position adjusting means provided at an outer periphery of the objective lens to move the observation sample in the optical axis direction of the objective lens through the sample base to set a focal point of the objective lens to the observation sample, and elastic means provided on the stage and so set relative to the sample base as to have a low rigidity in the optical axis direction of the objective lens and a high rigidity in a moving direction of the stage, wherein the position adjusting means has a fixing base for fixing the objective lens, a sample retaining base placing the observation sample thereon, and an operation ring threadably inserted over the fixing base and, by being rotated relative to the fixing base, moving in the moving axis direction of the objective lens and moving the sample retaining base in the optical axis direction of the objective lens to adjust a relative distance between the observation sample and the objective lens.
According to a main aspect of the present invention, a focus stabilizing apparatus is provided which comprises an objective lens arranged opposite to an observation sample, a stage so provided as to be movable in a direction orthogonal to an optical axis of the objective lens, a sample base placed on a stage to retain the observation sample, and position adjusting means provided at an outer periphery of the objective lens and moving the observation sample in an optical axis direction of the objective lens through the sample base to set a focal point of the objective lens to the observation sample, wherein the position adjusting means has a fixing base for fixing the objective lens, and a sample retaining base placing the observation sample thereon and threadably inserted over the fixing base and, being rotated relative to the fixing base, moving in the optical axis direction of the objective lens.
According to a main aspect of the present invention, a focus stabilizing apparatus is provided which comprises an objective lens arranged opposite to an observation sample, a stage so provided as to be movable in a direction orthogonal to an optical axis of the objective lens, a sample base placed on the stage to retain the observation sample, position adjusting means provided at an outer periphery of the objective lens and moving the observation sample in an optical axis direction of the objective lens through the sample base to set a focal point of the objective lens to the observation sample, and elastic means provided on the stage and so set relative to the sample base as to have a low rigidity in the optical axis direction of the objective lens and a high rigidity in a moving direction of the stage, wherein the position adjusting means has a fixing base for fixing the objective lens and a sample retaining base placing the observation sample thereon and threadably inserted over the fixing base and, by being rotated relative to the fixing base, moving in the optical axis direction of the objective lens.
In such focus stabilizing apparatus, the objective lens is fixed to the fixing base and threadably inserted directly into a revolver provided at a microscope body.
The position adjusting means has a rotation stop section arranged at the upper side of the sample retaining base, an intermediate seat arranged on the upper side of the rotation stop section and having the observation sample placed thereon, and a pin having one end mounted in the fixing base and the other end inserted through a hole in the rotation stop section and provided parallel to the optical axis direction of the objective lens.
According to a main aspect of the present invention, a focus stabilizing apparatus is provided which comprises an objective lens arranged opposite to an observation sample, a stage so provided as to be movable in a direction orthogonal to an optical axis of the objective lens, a sample base placed on the stage to retain the observation sample, and position adjusting means provided at an outer periphery of the objective lens and moving the observation sample in an optical axis direction of the objective lens through the sample base to set a focal point of the objective lens to the observation sample, wherein the position adjusting means has a fixing base for fixing the objective lens, a sample retaining base placing the observation sample thereon, fitted over an outer periphery of the fixing base and so provided as to be movable in the optical axis direction of the objective lens, and a friction member situated between the fixing base and the sample retaining base and retaining the sample retaining base by a friction force relative to the fixing base.
According to a main aspect of the present invention, a focus stabilizing apparatus is provided which comprises an objective lens arranged opposite to an observation sample, a stage so provided as to be movable in a direction orthogonal to an optical axis of the objective lens, a sample base placed on the stage to retain an observation sample, position adjusting means provided on an outer periphery of the objective lens and moving the observation sample in an optical axis direction of the objective lens through the sample base to set a focal point of the objective lens to the observation sample, and elastic means provided on the stage and so set relative to the sample base as to have a low rigidity in the optical axis direction of the objective lens and a high rigidity in a moving direction of the stage, wherein the position adjusting means has a fixing base for fixing the objective lens, a sample retaining base placing the observation sample thereon and fitted over an outer periphery of the fixing base and so provided as to be movable in the optical axis direction of the objective lens, and a friction member situated between the fixing base and the sample retaining base and retaining the sample retaining base by a friction force relative to the fixing base.
In the focus retaining apparatus, a sample retaining base grasping mechanism is provided for grasping and fixing the sample retaining base.
Further, a temperature sensor is provided on the fixing base to detect the ambient temperature and a temperature adjusting means is provided for adjusting the temperature of the fixing base and sample retaining base on the basis of a detection output of the temperature sensor to be made constant at all times.
According to a main aspect of the present invention, a focus stabilizing apparatus is provided which comprises an objective lens arranged opposite to an observation sample, a stage so provided as to be movable in a direction orthogonal to an optical axis of the objective lens, a sample base placed on the stage to retain the observation sample, and position adjusting means provided at an outer periphery of the objective lens and moving the observation sample in an optical axis direction of the objective lens through the sample base to set a focal point of the objective lens to the observation sample, wherein the position adjusting means has a fixing base for fixing the objective lens, a sample retaining base fitted over an outer periphery of the fixing base and so provided as to be movable in the optical axis direction of the objective lens, a piezoelectric actuator provided on the upper side of the sample retaining base and performing its extending/contracting operation in the optical axis direction of the objective lens, a sample base provided on the upper side of the piezoelectric actuator and placing the observation sample thereon and an electrostatic sensor provided on the upper side of the sample retaining base to detect a moving amount of the sample base.
According to a main aspect of the present invention, a focus stabilizing apparatus is provided which comprises an objective lens arranged opposite to an observation sample, a stage so provided as to be movable in a direction orthogonal to an optical axis of the objective lens, a sample base placed on the stage to retain the observation sample, position adjusting means provided at an outer periphery of the objective lens and moving the observation sample in an optical axis direction of the objective lens through the sample base to set a focal point of the objective lens to the observation sample, and elastic means provided on the stage and so set relative to the sample base as to have a low rigidity in the optical axis direction of the objective lens and a high rigidity in a moving direction of the stage, wherein the position adjusting means has a fixing base for fixing the objective lens, a sample retaining base fitted over an outer periphery of the fixing base and so provided as to be movable in the optical axis direction of the objective lens, a piezoelectric actuator provided on the upper side of the sample retaining base and performing its extending/contracting operation in the optical axis direction of the objective lens, a sample base provided on the upper side of the piezoelectric actuator and placing the observation sample thereon, and an electrostatic sensor provided on the upper side of the sample retaining base to detect a moving amount of the sample base.
According to a main aspect of the present invention, a focus stabilizing apparatus is provided which comprises an objective lens arranged opposite to an observation sample, a stage so provided as to be movable in a direction orthogonal to an optical axis of the objective lens, a sample base placed on the stage to retain the observation sample, and position adjusting means provided at an outer periphery of the objective lens and moving the observation sample in an optical axis direction of the objective lens through the sample base to set a focal point of the objective lens to the observation sample, wherein the position adjusting means has a fixing base for fixing the objective lens and having a flange at its outer periphery and a sample retaining base fitted over an outer periphery of the fixing base and so provided as to be movable in the optical axis direction of the objective lens and having a flange at its outer periphery, and a feed screw section provided between the flange of the fixing base and the flange of the sample retaining base to feed the sample retaining base in the optical axis direction of the objective lens relative to the fixing base.
According to a main aspect of the present invention, a focus stabilizing apparatus is provided which comprises an objective lens arranged opposite to an observation sample, a stage so provided as to be movable in a direction orthogonal to an optical axis of the objective lens, a sample base placed on the stage to retain the observation stage, position adjusting means provided at an outer periphery of the objective lens and moving the observation sample in an optical axis direction of the objective lens through the sample base to set a focal point of the objective lens to the observation sample, and elastic means provided on the stage and so set relative to the sample base as to have a low rigidity in the optical axis direction of the objective lens and a high rigidity in a moving direction of the stage, wherein the position adjusting means has a fixing base for fixing the objective lens and having a flange at its outer periphery, a sample retaining base fitted over the outer periphery of the fixing base and so provided as to be movable in the optical axis direction of the objective lens and having a flange at its outer periphery, and a feed screw section provided between the flange of the fixing base and the flange of the sample retaining base to feed the sample retaining base in the optical axis direction of the objective lens relative to the fixing base.
In the focus stabilizing apparatus, leaf springs are provided on the sample retaining base to fix the observation sample thereon.
Further, a mechanical coupling length between the objective lens and observation sample is set by the fixing base, sample retaining base and operation ring.
A mechanical coupling length between the objective lens and the observation sample is set by the fixing base and the sample retaining base.
In the focus stabilizing apparatus, the fixing base, operation ring and sample retaining base are made of at least two different kinds of materials and selectable in their dimensions.
The operation ring and sample retaining base are made of at least two different kinds of materials and selectable in their dimensions.
The operation ring and sample retaining base are formed of materials of different linear expansion coefficients.
An auxiliary member is located between the operation ring and the sample retaining base and made of a material different in liner expansion coefficient from the materials of the operation ring and sample retaining base.
The elastic means is comprised of leaf springs provided on the stage and arranged along the direction orthogonal to the optical axis of the objective lens and a magnet provided on the leaf spring to attract the sample base.
According to a main aspect of the present invention, a focus stabilizing apparatus is provided which comprises an objective lens arranged opposite to an observation sample, position adjusting means provided at an outer periphery of the objective lens and moving the observation sample in an optical axis direction of the objective lens to set a focal point of the objective lens to the observation sample, a minute movement mechanism for minutely displacing the objective lens in the optical axis direction of the objective lens, displacement amount detecting means for detecting a displacement amount of the objective lens, and control means for operating the minute movement mechanism on the basis of a detection output of the displacement amount detecting means to control a relative distance between the objective lens and the observation sample to a predetermined distance.
According to a main aspect of the present invention, a focus stabilizing apparatus is provided which comprises an objective lens arranged opposite to an observation sample, a stage so provided as to be movable in a direction orthogonal to an optical axis of the objective lens, a sample base placed on the stage to retain the observation sample, position adjusting means provided at an outer periphery of the objective lens and moving the observation sample in an optical axis direction of the objective lens through the sample base to set a focal point of the objective lens to the observation sample, a minute movement mechanism for minutely displacing the objective lens in the optical axis direction of the objective lens, displacement amount detecting means for detecting a displacement amount of the objective lens, control means for operating the minute movement mechanism on the basis of a detection output of the displacement amount detecting means to control a relative distance between the objective lens and the observation sample to a predetermined distance, and elastic means provided on the stage and so set relative to the sample base as to have a low rigidity in the optical axis direction of the objective lens and a high rigidity in a moving direction of the stage.
In the focus stabilizing apparatus, the position adjusting means has a fixing base for fixing the objective lens through the minute movement mechanism, a sample retaining base for placing the observation sample thereon, and an operation ring threadably inserted over the fixing base and, by being rotated relative to the fixing base, moving in the optical axis direction of the objective lens and moving the sample retaining base in the optical axis direction of the objective lens to adjust a relative distance between the observation sample and the objective lens.
A mechanical coupling length between the objective lens and the observation sample is set by the fixing base for fixing the objective lens through the minute movement mechanism, the sample retaining base for placing the observation sample thereon and the operation ring inserted over the fixing base and, by being rotated relative to the fixing base, moving in the optical axis direction of the objective lens and moving the sample retaining base in the optical axis direction of the objective lens to adjust a relative distance between the observation sample and the objective lens.
The minute movement mechanism has a moving stage relative to which the objective lens is provided, and an actuator for minutely moving the moving stage in the optical axis direction of the objective lens.
The minute movement mechanism has a moving stage relative to which the objective lens is provided, and piezoelectric actuators arranged in those positions symmetric relative to the optical axis of the objective lens to minutely move the moving stage in the optical axis direction of the objective lens.
The displacement amount detecting means is comprised of an electrostatic capacity sensor.
The control means has means for receiving, as inputs, an objective lens displacement amount detected by the displacement amount detecting means and an instruction value representing the position of the objective lens, means for finding a deviation between the displacement amount of the objective lens and the instruction value, and means for performing operation control of the minute movement mechanism in accordance with the deviation to move the objective lens to a position designated by the instruction value.
The elastic means is comprised of leaf springs mounted on the stage and arranged along the direction orthogonal to the optical axis of the objective lens and a magnet mounted on the leaf spring to attract the sample base.
According to a main aspect of the present invention, a focus stabilizing apparatus is provided which comprises an objective lens arranged opposite to an observation sample, a minute movement mechanism for minutely displacing the objective lens in the optical axis direction of the objective lens, displacement amount detecting means for detecting a displacement amount of the objective lens, and control means for operating the minute movement mechanism on the basis of a detection output of the displacement amount detecting means to control a relative distance between the objective lens and the observation sample to a predetermined distance.
According to a main aspect of the present invention, a focus stabilizing apparatus is provided which comprises an objective lens arranged opposite to an observation sample, a fixing base for fixing the objective lens, a minute movement table on which the objective lens is provided, parallel springs situated between the fixing base and the minute movement table to allow the minute movement table to be moved in an optical axis direction of the objective lens, an actuator provided between the fixing base and the minute movement table to minutely displace the minute movement table in the optical axis direction of the objective lens, a displacement sensor for detecting a displacement amount of the objective lens, and control means for allowing the actuator to perform its extending/contracting operation on the basis of a detection output of the displacement sensor to control the objective lens and bring it to a just-in-focus position relative to the observation sample.
In the focus stabilizing apparatus, the control means has a memory section for storing an output of the displacement sensor corresponding to a just-in-focus state between the observation sample and the objective lens, a comparing section for comparing an output of the displacement sensor and an output of the displacement sensor stored in the memory section, and a control section for outputting an electric signal for canceling a distance variation between the observation sample and the objective lens on the basis of a result of comparison by the comparing section to the actuator.
According to a main aspect of the present invention, a focus stabilizing apparatus is provided which comprises an objective lens arranged opposite to an observation sample, position adjusting means provided at an outer periphery of the objective lens and moving the observation sample in an optical axis direction of the objective lens to set a focal point of the objective lens to the observation sample, a minute movement mechanism for minutely varying a distance between the observation sample and the objective lens in the optical axis direction, and control means for operating the minute movement mechanism to make a fine adjustment of the distance between the observation sample and the objective lens.
According to a main aspect of the present invention, a focus stabilizing apparatus is provided which comprises a fixing base having an objective lens mounting section, a sample base for supporting an observation sample, and position adjusting means provided on the fixing base to allow the sample base to be moved in an optical axis direction of the objective lens.
In the focus stabilizing apparatus, the position adjusting means has a fixing base for fixing the objective lens, an operation ring inserted over the fixing base and, by being rotated, moving in the optical axis direction of the objective lens, and a sample retaining base so provided as to be movable in the optical axis direction and, upon a rotation operation of the operating ring, adjusting a distance between the observation sample and the objective lens.
According to the present invention, the mechanical coupling length between the objective lens and the observation sample is determined by only the position adjusting means provided relative to the objective lens and can be set to be very short. By doing so, there is almost no variation in a positional relation between the objective lens and the observation sample even if the ambient temperature varies. The structure suffers no adverse effect from an external vibration and the sample can be observed at all times under a stable condition.
After the focal point of the objective lens has been set to the observation sample, the observation sample can be moved in a direction orthogonal to the optical axis of the objective lens simply by moving the stage and it is also possible to readily position the observation sample in a moving direction of the stage.
Further, as the position adjusting means use is made of at least two different kinds of materials and its component elements are selectable in their materials and dimensions. It is, therefore, possible to prevent an observation image from being degraded even if the ambient temperature varies.
Further, the mechanical coupling length between the objective lens and the observation sample is set to be short and the operation of the minute movement mechanism is controlled in accordance with a deviation between the displacement amount of the objective lens and the instruction value to allow the objective lens to be set to a position designated by the instruction value. Therefore, even if the ambient temperature varies, there is almost no variation in positional relation between the objective lens and the observation sample. The structure also suffers no adverse effect from external vibrations and the objective lens can be set to a desired position given by the instruction value and the observation sample can be observed, under a stable way, over an extended period of time.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.