Chromatic method and apparatus for conducting microscopic examinations at a plurality of magnifications

Abstract

A chromatic method and apparatus for conducting microscopic examinations at a plurality of magnifications provide for illuminating a microscopic object with a plurality of colors of light, conducting the light transmitted by the object along different paths for different colors, and producing different degrees of magnification along the different paths.

Description

BACKGROUND OF THE INVENTION

This invention relates to a chromatic method and apparatus for conducting microscopic examinations at a plurality of magnifications.

Efficient operation of computerized automatic or semi-automatic equipment for microscopy necessitates an ability to change the degree of magnification rapidly during examination of microscopic objects, and a rapid change in magnification cannot be accomplished in a practical manner by changing the objective or the eyepiece. Consequently, a need exists for a method and apparatus suited for making a change in magnification rapidly and in a practical manner.

SUMMARY OF THE INVENTION

The invention provides a chromatic method of conducting microscopic examinations at a plurality of magnifications which includes the steps of illuminating a microscopic object with a plurality of colors of light, conducting the light transmitted by the object along different paths for different colors, and producing different degrees of magnification along the different paths.

The invention also provides chromatic apparatus for conducting microscopic examinations at a plurality of magnifications which includes a color differentiating element adapted to be disposed in the path of light transmitted by an illuminated object, said element transmitting light of different colors in different directions therefrom, means providing separate light paths for different colors transmitted from the element, and a magnifying lens disposed in at least one of the separate paths for producing different degrees of magnification along different light paths from an illuminated object. A preferred embodiment of the apparatus includes an objective lens adapted to be disposed in the path of light between an illuminated object and the differentiating element.

Employing further preferred embodiments of the method and apparatus, the object is illuminated selectively by light of different colors, and the light from the separate paths is conducted to a common terminal path, so that images of the several different degrees of magnification may be transmitted in turn to the same receiving point for purposes of examination. Employing still further preferred embodiments, light of substantially the same order of intensity for each of the several colors is delivered to the common terminal path.

The chromatic method and apparatus are adapted for effecting rapid changes of magnification by changing the color of illumination of an object. It is within the scope of the invention, in addition or alternatively, to illuminate an object simultaneously with a plurality of light colors, for obtaining a plurality of simultaneous readings at different degrees of magnification.

Employing the new method and apparatus, there need be no movement of microscope lenses for changing the degree of magnification. The remaining apparatus employed for magnification also can be mounted fixedly and compactly. Consequently, wear is minimized, thereby preserving the high degree of accuracy required in microscopic analysis.

BRIEF DESCRIPTION OF THE DRAWING

The attached drawing is a diagrammatic representation of apparatus according to a preferred embodiment of the invention, and also illustrates a preferred manner in which the method of the invention can be carried out.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawing, the preferred embodiment of the invention is illustrated in its application to the examination of an object or specimen on a microscope slide 10. The slide 10 is mounted adjacent to and between a condenser lens 12 beneath the slide and an objective lens 14 above the slide. The condenser 12 can be mounted on a microscope stage, not shown. In the particular arrangement illustrated, an object on the slide 10 is illuminated by a lamp 16 and a sub-stage mirror 18 which serves to reflect light rays from the lamp at right angles to the incident path and in the direction of the axis 20 of the condenser lens 12 and the objective lens 14. It will be understood that the light source can be disposed in other arrangements, such as on the axis 20, with elimination of the mirror 18.

A conventional microscope can include structure similar to the foregoing, including one or more objective lenses, and an eyepiece or eyepieces. The objective lens and/or the eyepiece can be changed or adjusted, to change the degree of magnification of the object on the slide 10. The present invention especially is adapted for use of a fixed lens system, without need for changing or adjusting a lens when the degree of magnification is to be changed. Consequently, the time lag required for such lens changes is eliminated, and there is no wear in apparatus required for making such changes with resulting decrease in accuracy. It will be apparent that, nevertheless, one or more lenses can be mounted for movement or be changeable, if desired, for additional versatility and adptability.

The object on the slide 10 is illuminated with light of different colors, and the color of the illumination determines the resulting degree of magnification. For this purpose, a source of illumination selectively with light of different colors is provided, and in the illustrative embodiment, it includes a color filter wheel 22 interposed between the lamp 16 and the sub-stage mirror 18. The filter wheel is divided into sections embodying different color filters, for transmitting light of different colors or ranges of wavelengths from different sections to the mirror 18. For example, in the illustrative embodiment, the filter wheel 22 includes: one section transmitting both green and orange colored light having wavelength bands in the regions of 500 and 600 nm. (nanometers) respectively; and one section transmitting yellow-green colored light having a wavelength band in the region of 565 nm. The color of the transmitted light can be changed very rapidly, operating the filter wheel in a conventional manner, preferably by rotating the wheel in step-wise fashion to change the color. It will be apparent that, alternatively, any of various other suitable arrangements for providing and rapidly changing light of different colors can be employed.

Light of the desired color is transmitted from the filter wheel 22 to the sub-stage mirror 18, from whence it is transmitted by reflection to the condenser 12 and to the object on the slide 10. Light transmitted by the object passes through the objective lens 14, and an image of the object is produced that is magnified according to the power of the lens. The degree of magnification produced by the lens 14 can be, for example, forty times.

Light is transmitted from the objective lens 14 in the direction of the lens axis 20 in a common initial light path 24 provided in the apparatus. The initial light path 24 terminates at a first color differentiating element 26. In the illustrative embodiment, the element 26 is constructed to function as an interference color filter which passes a light band of a certain color, and also as a folding (plane) mirror (reflector), which reflects light of one or more other colors. The plane of the reflective surface 26a on the element 26 is disposed at a preferred angle of 45.degree. to the lens axis 20 and the initial light path 24 coincident with the axis. In the illustrative embodiment, the differentiating element 26 is adapted to pass the orange light of 600 nm. wavelength and to reflect the green and yellow-green light of 500 and 565 nm. wavelength. It will be understood, however, that the properties of a color filter, such as are obtained by applying a proper coating to a light-transmitting substrate, are such that less than 100 percent of the light of the selected wavelength band at 600 nm. is transmitted through the differentiating element 26. At times, depending upon the quality of the element 26, a minor quantity of such light is reflected from the surface 26a of the element.

The light passing through the differentiating element 26 is transmitted therefrom in the direction of the lens axis 20, and follows an angular, separate first light path 28 having a first section 28a extending in the direction of the axis 20 and a second section 28b extending at right angles thereto. In the illustrative embodiment, orange colored light follows the first path 28, and it is magnified by an eyepiece having a field lens 32 in the first section 28a and an eye lens 34 in the second section 28b of the path. The degree of magnification produced by the eyepiece can be, for example, five times, and yielding a total exemplary magnification of 200. An aerial image is formed as indicated by a broken line at 36. The angularity of the first light path 28 is achieved by disposing a folding mirror 38 in the path following the field lens 32, with the plane reflective surface 38a of the mirror disposed at an angle of 45.degree. to the lens axis 20 and the first section 28a of the path.

The light transmitted by reflection from the reflective surface 26a of the differentiating element 26 is conducted along first and second sections 30a and 30b of an angular, separate second light path 30, the path sections being at right angles to each other. The reflected light, including either the green light of 500 nm. wavelength or the yellow-green light of 565 nm. wavelength, and any reflected minor proportion of orange light of 600 nm. wavelength, is transmitted to a blocking color filter 40 disposed in the first path section 30a perpendicularly thereto. The blocking filter 40 is adapted to block the orange light and pass a preponderating amount of the remaining colors of light. Alternatively, with a more nearly perfect differentiating element 26, i.e., which reflects at most an insignificant amount of light of 600 nm. wavelength, the blocking filter 40 can be eliminated.

In the illustrative embodiment, the first section 30a of the second light path 30 terminates at a second color differentiating element 42 having a plane reflective surface 42a disposed at an angle of 45.degree. to the direction of the first path section 30a. The second differentiating element 42 is similar in function to the first differentiating element 26, and is constructed to pass the green light of 500 nm. wavelength, and to reflect the yellow-green light of 565 nm. wavelength. The light passed by the second element 42 follows a separate third light path 44, which extends in the same direction as and beyond the first section 30a of the second path 30. The reflected light follows the second path section 30b of the second path 30.

A second blocking color filter 46 is disposed in the second section 30b of the second light path 30 perpendicularly to the section. The second blocking filter 46 is adapted to block passage of any green light of 500 nm. wavelength, which is reflected in a minor amount by the second differentiating element 42 rather than being passed thereby, and to pass a preponderating amount of the reflected yellow-green light of 565 nm. wavelength. As in the case of the first differentiating element 26, the use of a second differentiating element 42 of sufficiently high color separating ability will enable the elimination of the second blocking filter 46.

A second eyepiece 48 is disposed in the second section 30b of the second light path 30, so that the path section follows the axis of the second eyepiece. The second eyepiece can produce a magnification of 25.times., for example, which together with an objective lens 14 having a magnification of 40.times., produces an overall magnifying power of 1,000. An aerial image is formed as represented by a broken line at 50.

The sections 28a, 28b, 30a and 30b of the separate light paths 28 and 30 form the sides of a rectangle. The separate paths 28 and 30 thus are equal in length, and they converge at a beam splitter 52 having a reflective layer 52a. The reflective layer 52a is adapted to reflect a major portion of the light incident to either its front surface or its back surface, and to pass a minor proportion of such light. Thus, the layer 52a is adapted to reflect most of the yellow-green colored light of 565 nm. wavelength from the second section 30b of the second light path 30, and to pass the balance. The layer 52a is at an angle of 45.degree. to the second path section 30b, so that the light rays are reflected at an angle of 90.degree. to the second path section 30b, and are conducted along a terminal path 54 leading to a first sensor 56. The passed light follows a path 58, the light from which is dissipated.

The layer 52a of the beam splitter 52 also is adapted to pass a minor proportion and reflect the balance of the light rays from the second section 28b of the first separate light path 28. The passed light from the latter section 28b follows the terminal path 54, and the reflected light from the latter section follows the dissipation path 58. In this manner, beam splitter 52 serves to equalize the intensity of the light reaching the terminal path 54 from the separate paths 28 and 30, and delivers light of substantially the same order of intensity to the sensor 56. In the illustrative embodiment, about 8 percent of the light from the second path section 28b of the first path 28 is passed to the terminal path 54, and about 92 percent is reflected to the dissipation path 58. Similarly, about 92 percent of the light from the second path section 30b of the second path 30 is reflected to the terminal path 54, and about 8 percent is passed to the dissipation path 58.

The illustrative arrangement of different paths leading from the slide 10 to the sensor 56 via the separate paths 28 and 30 allows an examination to be made at one magnification at a time, employing the appropriate setting of the color filter wheel 22, i.e., at the 500 and 600 nm. setting, or at the 565 nm. setting. In each case, an examination is made by the same agency or at the same point, i.e., by the sensor 56, which can be a television camera, for example. It will be apparent, however, that, alternatively, provision can be made for separate light paths that do not terminate in a common path, such as the terminal path 54, but lead to separate sensors. In such case, it is possible to make examinations at two different magnifications at the same time, while illuminating the slide 10 with light of two or more colors at the same time. This manner of operation is illustrated by reference to the third separate light path 44.

The light of 500 nm. wavelength which is passed by the second differentiating element 42 and follows the third separate path 44 terminates in a second sensor 60 serving any desired purpose. Consequently, when the color filter wheel 22 is adjusted to transmit light of 600 and 500 nm. wavelength together, light of the respective wavelengths is transmitted simultaneously along separate paths and at different magnifications to the respective sensors 56 and 60, which can operate simultaneously to perform separate functions. Similarly, if desired, light of 500 nm. wavelength might be transmitted together with light of 565 nm. wavelength, for simultaneous examinations by the sensors 56 and 60. It will be noted that in either of the foregoing alternatives, the image reaching the second sensor 60 has been magnified but once, by the objective lens 14, so that the magnification at the second sensor is 40.times.. The illustrative system thus provides three different degrees of magnification.

In the event that it is not desired to provide for a simultaneous second examination, the sensor 60 is eliminated, and the appropriate section of the filter wheel 22 can be constructed so as to transmit only light of 600 nm. wavelength, and not light of 500 nm. wavelength. There is no need then for an element to pass 500 nm. light to the sensor 60, so that the second differentiating element 42 can be replaced by a folding mirror similar to the previously described folding mirror 38, for reflecting the 565 nm. light. The second blocking filter 46 can be eliminated, since its function is to prevent passage of 500 nm. light, no longer transmitted.

While preferred embodiments of the method and apparatus of the invention have been described and illustrated, it will be apparent that various changes and modifications can be made therein within the spirit and scope of the invention. It is intended that such changes and modifications be included within the scope of the appended claims.

Claims

What is claimed is:

1. A chromatic method of conducting microscopic examinations of an illuminated object at a plurality of magnifications, in which neither the object nor any magnifying lenses are required to be moved, which comprises the steps of:

illuminating the object with a plurality of different colors of light,

conducting the light transmitted by said object along different paths for said different colors, and

producing different degrees of magnification along said different paths.

2. A method according to claim 1 wherein said step of illuminating said object is accomplished by employing selectively light of different colors, and including the step of conducting the light from said paths to a common terminal path.

3. A method according to claim 2 wherein said step of conducting includes the step of regulating the intensity of the light of said different colors to be substantially the same intensity when supplied to said common terminal path.

4. A method according to claim 1 including the step of generating said different paths by color differentiation.

5. Chromatic apparatus for conducting microscopic examinations of an illuminated object at a plurality of magnifications, in which neither the object nor any magnifying lenses are required to be moved, which comprises, in combination:

a color differentiating element adapted to be disposed in the path of light transmitted by the illuminated object, said color differentiating element transmitting light of different colors in different directions therefrom and along first and second separate light paths, and

a magnifying means disposed in at least one of said separate paths for producing different degrees of magnification along said different light paths from the illuminated object.

6. Apparatus according to claim 5 further including an objective lens adapted to be disposed in the path of light between the illuminated object and said differentiating element.

7. Apparatus according to claim 5 including magnifying lenses having different magnifying powers disposed in different ones of said separate paths.

8. Apparatus according to claim 5 wherein said differentiating element is a color filter adapted to pass at least one color and reflect at least one different color.

9. Apparatus according to claim 8 further including a second color filter disposed in the light path for said reflected color and adapted to pass said reflected color while blocking passage of any reflected components of said passed color.

10. Apparatus according to claim 5 further including means for converging said first and second light separate paths into a common terminal path.

11. Apparatus according to claim 10 wherein said converging means includes reflecting means disposed in at least one of said separate paths.

12. Apparatus according to claim 11 wherein said reflecting means includes a color filter adapted to pass at least one color and reflect at least one different color.

13. Apparatus according to claim 10 further including means for delivering to said terminal path light of said colors having substantially the same order of intensity.

14. Apparatus according to claim 13 wherein said delivery means includes a beam splitter.

15. Apparatus according to claim 5 wherein said separate paths are equal in length.

16. Apparatus according to claim 5 further including means for illuminating said object selectively by light of different colors.

17. Apparatus according to claim 5 including a sensor disposed at the end of each of said separate light paths for receiving two different magnifications of the illuminated object.

18. Apparatus according to claim 5 which includes color selecting structure which causes said color differentiating element to receive simultaneously at least two different colors from the illuminated object.

19. Apparatus according to claim 5 in which said color differentiating element, said separate light paths, magnifying means and the object are stationary at least during the production of the different degrees of magnification.

20. Apparatus according to claim 5 which includes a second color differentiating element positioned in one of said separate light paths for directing at least one color along a third separate light path.

21. Apparatus according to claim 20 which includes color selecting structure for selectively causing the light transmitted from the object to said color differentiating elements to be more than of two colors, each color being directed to a different one of said light paths.

22. Apparatus according to claim 20 including a sensor disposed at the end of each of said separate light paths for receiving different degrees of magnification of the illuminated object.

23. Apparatus according to claim 22 in which said color selecting structure causes at least one of said color differentiating elements to receive simultaneously at least two different colors from the illuminated object.