Microscope provided with automatic focusing device having memory means

• US 4,661,692 A
• Filed: 03/26/1984
• Issued: 04/28/1987
• Est. Priority Date: 03/29/1983
• Status: Expired due to Term

• Current Assignee: Olympus Optical Corporation Limited (Olympus Corporation)
• Original Assignee: Olympus Optical Company Ltd. (Olympus Corporation)
• Inventors: Kawasaki, Masami
• Primary Examiner(s): Nelms, David C.
• Application Number:
  US06/593,311
• Time in Patent Office: 1,128 Days
• Field of Search: 250/201, 250/204, 250/237 R, 250/216, 250/205, 354/404, 354/405, 354/406, 354/407, 364/167, 356/1, 356/4, 350/507, 350/518, 350/520
• US Class Current: 250/201.2
• CPC Class Codes: G02B 21/244 using image analysis techniques

Abstract

A microscope provided with a photographing device which has a structure for always projecting an optimum image onto an image pickup device, a structure for correcting image data obtained from the image pickup device to eliminate the influences of the unevenness of the brightness distribution of the projected image and the unevenness of the characteristics of each picture element forming the image pickup device, a structure for bringing a focusing stage to an in-focus position adapted to an objective selected to be used on the basis of the corrected image data and a structure for making an out-focus indication when the focusing stage is brought to a predetermined upper limit position or lower limit position, to make high precision, quick automatic focusing possible.

Claims

1. A microscope which includes a field stop, an aperture stop, means for producing a light, a plurality of condenser lens means for condensing the light emitted from said light producing means source and capable of being selectively inserted into a light path, a focusing stage, a revolver, and a plurality of objectives with magnifications different from each another attached to the revolver, and which is provided with an automatic focusing device, comprising:

data input means for inputting data relating to the magnification and kinds of the objectives;

memory means, connected to said data input means, for memorizing said data relating to a plurality of objectives input by said data input means;

first driving controlling means coupled to said memory means, for controlling at least one of adjustment of the light producing means, field stop, aperture stop, switching of a condenser lens, movement of a stage, and switching of a light path, while referring to data read out relating to a selected objective, which is selected to be used, so as to be able to perform optimum focusing for said selected objective;

image pickup means, receiving a projected image formed by said selected objective, for focusing said image,

second driving controlling means, connected to said image pickup means and said memory means for driving said image pickup means, and

a central processing unit, coupled to said second driving controlling means.

2. A microscope according to claim 1, in which said image pickup means is a CCD element including a plurality of picture elements, and wherein said second driving controlling means includes clock driving control means for driving said CCD element to provide an optimum output for the use of a dynamic range in the amount of light.

3. A microscope according to claim 1 further comprising operating means for performing manual adjustment for an illuminating condition by at least one of said field stop, aperture stop and switching of the condenser lens in accordance with a preference of an observer, to correct the illuminating condition on a sample determined as automatic optimum values, and means for memorizing the result of the adjustment by correcting coefficients to the automatic optimum values already determined, the illuminating condition being returned to a manually adjusted condition after the focusing has been completed.

4. A microscope according to claim 3, in which said correcting coefficients are used as they are even when the objective selected to be used is changed, in order to enable manual correction of an illuminating condition of the microscope using other objectives.

5. A microscope according to claim 3 further comprising means for returning said correcting coefficients to a standard value.

6. A microscope according to claim 3 further comprising sensor means for detecting positions of said stage which are different from each other, a standard position of said stage being set apart by a predetermined a distance from a theoretical in-focus position of the objective in a direction of departing from said objective, the stage being moved to said standard position when operating instructions for automatically focusing are issued by said central processing unit judging by comparison between the stage position value and the standard position value, and when said stage is in a position departing from said standard position in the direction of departing from said objective, an operation for focusing being carried out when said stage reaches said standard position, and said operation being repeated while moving stepwise said stage by a predetermined distance until an in-focus state is obtained.

7. A microscope according to claim 6, in which said operation for focusing to be performed on the basis of said image data is carried out on the basis of a calculated contrast value in the first stage and is carried out on the basis of a correlating calculation in the second stage wherein a predetermined contrast value has be obtained.

8. A microscope according to claim 6, in which the predetermined distance of said stage to be moved on the basis of said operation for focusing corresponds to a focal depth of an objective selected to use.

9. A microscope according to claim 6, in which an upper limit position and lower limit position are provided within a range of the movement of said stage so as to sandwich said standard position therebetween, and at least one of said stage and an indicating device is controlled when said upper limit position or lower limit position is detected by said sensors.

10. A microscope according to claim 1 further comprising a plurality of photographing eyepieces inserted selectively in the light path, each photographing eyepiece having a predetermined magnification being capable of being inserted into the light path to increase the resolving power of a sample image to be projected on said image pickup device when an automatically focusing is to be performed.

11. A microscope according to claim 1 wherein said first driving controlling means controls the adjustment of the light producing means, field stop, aperture stop, the switching of the condenser lens and the like while referring to said data read out on the objective selected for at least one of observation and photographing.

12. A microscope according to claim 1 further comprising correcting means for correcting a resulting unevenness of illumination on said image pickup means, which unevenness results from optical strain due to the optical system through the illuminating sytstem to the image pickup device, and from interelement characteristics of the image pickup device itself.

13. A microscope according to claim 1 in which said correcting means comprises program execution means for preparing correction data and said memory means for memorizing the output value of said program execution means with respect to each objective before a sample is observed by the microscope, and is also for correcting an output for focusing through the objective corresponding to the memorized value when the sample is to be observed by the microscope.