JP3645625B2 - Microscope automatic focus detection method, microscope automatic focus detection device, and microscope using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is a method of dividing an imaging area.Microscope automatic focus detection method, microscope automatic focus detection apparatus, and microscope using the sameAbout.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a technique related to focus detection of an optical device such as a microscope has been invented in many fields, and one of them is a distance measuring method (hereinafter referred to as an area) based on area division as a technique for controlling focus on a target subject with high accuracy. Abbreviated as division method).
[0003]
In this area division method, the relative distance between the subject and the objective lens is controlled and focused from the calculation results of a plurality of focus detections obtained by dividing the distance measurement range into a plurality of blocks.
[0004]
For example, Japanese Patent Laid-Open No. 2-109008 discloses a method of selecting a plurality of focus detection calculation results for each area by majority in the area division method and performing focus control (hereinafter abbreviated as AF control).
[0005]
Japanese Patent Laid-Open No. 2-297514 invents a sensor in which two sensors having a fixed distance measuring range in the horizontal and vertical directions are arranged.
[0006]
[Problems to be solved by the invention]
However, when these methods are applied to a microscope, there are practically insufficient points.
[0007]
microscopeUsed inOne factor that deteriorates the focusing accuracy in automatic focus detection is dust attached to the slide glass or cover glass. That is, a dust image several thousand to several hundreds [μm] apart from the subject image is mixed, and the focusing accuracy of only the subject is remarkably lowered.
[0008]
As an improvement measure against the deterioration of the focusing accuracy, if focusing control by area division is always performed, the control becomes complicated and the focusing time, which is an important autofocus performance, is reduced.
[0009]
Further, in the microscope, the objective lens magnification for subject observation is variable from an extremely low magnification such as 1 × to 200 ×, so that the size of the dust image also changes, and the ratio of the dust image mixing to the subject image changes. For example, FIG. 9 shows a model in which dust is mixed in the objective lens ranging area. FIG. 4A shows the relationship between the distance measurement area and the dust image ratio at an objective lens magnification of 1 × and FIG. 4B at 4 ×. In addition, (A) to (G) in the figure indicate the divisions of the imaging area. When the objective lens magnification in FIG. 10A is 1 ×, noise images such as dust are mixed only in the divided area (C), but in FIG. 10B, the divided areas (A) and (C). In order to eliminate this noise area and stabilize the control, more complicated control is required. Therefore, the focusing time is reduced.
[0010]
Accordingly, an object of the present invention is to enable focus detection with high accuracy and high speed even when a noise image typified by dust other than the subject exists in the subject.Microscope automatic focus detection method, microscope automatic focus detection apparatus, and microscope using the sameIs to provide.
[0011]
[Means for Solving the Problems]
  In order to achieve the above object, an invention corresponding to claim 1 is an image forming method in which an optical image of a copy body placed on an objective lens and a stage is captured via the objective lens and an object image is formed at a predetermined position. An imaging system comprising an optical system and a plurality of light receiving elements for reading a front pin image and a rear pin image formed in front and rear positions optically conjugate with respect to a predetermined imaging surface of the imaging optical system; Area dividing means for dividing the imaging area captured by the means into a plurality of areas,In the area dividing means according to the size of the objective lens, the area ratio focusing signal output means for outputting a target focusing signal from the focused state of each division of the optical image divided by the area dividing means. Area variable means for changing the number of light receiving elements in each area or changing the number of divisions of the imaging areaThis is an automatic focus detection apparatus for a microscope.
  The invention corresponding to claim 1 is an object lens.MagnificationDepending on sizeThe area size of the area division is variable. For this reason, it becomes possible to stabilize the ratio of noise images such as dust in the distance measurement area, so that complicated control can be omitted.Focusing time is shortened and highly accurate AF can be performed.
[0013]
  To achieve the object, the claims2The invention corresponding toIt is as follows. That is, the area fractional focus signal output means is arranged before and after the target imaging area. 2 The focus signal is obtained using another imaging area excluding the target imaging area when the difference value between the back pin contrast and the front pin contrast is opposite in one imaging area. 1 Microscope automatic focus detection deviceIt is.
  Claim2According to the invention corresponding to the above, in the AF control by area division, when two adjacent front and rear areas become in-focus signals in the opposite direction, the other areas excluding the opposite two areas are used for the alignment. Since control is performed so as to obtain a focus signal, it is possible to focus on a subject with high accuracy without hunting even if the subject is thick or dust or the like is mixed in the subject image.
[0015]
  To achieve the object, the claims3The invention corresponding toAn objective lens, an imaging optical system that captures an optical image of a copy placed on the stage through the objective lens, and forms a subject image at a predetermined position; and a predetermined imaging plane of the imaging optical system An imaging means comprising a plurality of light receiving elements that read front and rear pin images formed at optically conjugate front and rear positions, and an area dividing function for dividing an imaging area imaged by the imaging means into a plurality of areas An area fractional focus signal output function that outputs a target focus signal from the focus state of each section of the optical image divided by the area division function, and depending on the magnification of the objective lens, An automatic microscope focus detection apparatus comprising: an arithmetic processing unit configured to change the number of light receiving elements in each area in the area division or to change the division number of the imaging area.It is.
  Claim3According to the invention corresponding to the above, the size of the area division area is varied depending on the magnification of the objective lens. For this reason, the ratio of noise images such as dust in the distance measurement area can be stabilized, and complicated control can be omitted, so that the focusing time can be shortened and highly accurate AF can be performed.
[0016]
  To achieve the object, the claims4The invention corresponding toThe configuration is as follows. That is, the area fractional focus signal output function is
Before and after the target imaging area 2 When the difference value between the rear pin contrast and the front pin contrast is opposite in one imaging area, the focus signal is obtained using the other imaging areas except the target imaging area.
Claims characterized in that Three Microscope automatic focus detection deviceIt is.
  Claim4According to the invention corresponding to the above, in the AF control by area division, when two adjacent front and rear areas become in-focus signals in the opposite direction, the other areas excluding the opposite two areas are used for the alignment. Since control is performed so as to obtain a focus signal, it is possible to focus on a subject with high accuracy without hunting even if the subject is thick or dust or the like is mixed in the subject image.
  In order to achieve the object, the claims5The invention corresponding toClaim 1 A microscope using a microscope automatic focus detection device, wherein the microscope automatic focus detection device according to any one of claims 4 to 4 is provided in a microscope.It is.
  Claim5According to the invention corresponding to the above, the size of the area division area is varied depending on the magnification of the objective lens. For this reason, it becomes possible to stabilize the ratio of noise images such as dust in the distance measurement area, and it is possible to omit complicated control, so that the focusing time during microscope operation is shortened and high-precision AF is performed. be able to
.
[0017]
  PreviousClaims to achieve the purpose6In the invention corresponding to the above, an optical image of a copy placed on a stage is taken in via an objective lens, and a subject image is formed at a predetermined position by an imaging optical system, and the image is formed on a predetermined imaging surface of the imaging optical system. On the other hand, the front pin image and the rear pin image formed at optically conjugate front and rear positions are read by an image pickup unit including a plurality of light receiving elements, and an area division for dividing the image pickup area picked up by the image pickup unit into a plurality of areas Function and an area fraction focus signal output function for outputting a target focus signal from the focus state of each section of the optical image segmented by the area division function, and depending on the magnification of the objective lens The microscope automatic focus detection method is characterized in that the number of light receiving elements in each area in the area division is variable or the number of divisions in the imaging area is variable.
  Claim6According to the invention corresponding to the above, the size of the area division area is varied depending on the magnification of the objective lens. For this reason, it becomes possible to stabilize the ratio of noise images such as dust in the distance measurement area, and it is possible to omit complicated control, so that the focusing time during microscope operation is shortened and high-precision AF is performed. be able to.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
<First Embodiment> Based on FIG.Microscope automatic focus detection deviceThe schematic configuration of will be described. As this schematic configuration, an objective lens 3 and an imaging optical system that takes in a light image of the subject S placed on the stage 1 through the objective lens 3 and forms a subject image at a predetermined position, for example, an imaging lens 4; Imaging means comprising a plurality of light receiving elements for reading a front pin image and a rear pin image formed at front and rear positions optically conjugate with respect to a predetermined imaging surface of the imaging lens 4, for example, a CCD sensor 6 and a CCD sensor 6 An area dividing means for dividing the imaging area imaged in a plurality of areas, an area dividing contrast calculating means for calculating a contrast value for each of the divided areas divided by the area dividing means for the front pin image and the rear pin image, and the area The divided contrast calculation means divides the imaging area into a plurality of areas and the fractional focus signal output means for outputting a target focus signal from the focus state for each section. A total range contrast calculating means for calculating the contrast values of the front pin image and the rear pin image in the entire range, a full range focus signal output means for outputting a focus signal by the full range contrast calculating means, and an area fraction focus Drive means such as a drive circuit 13 for receiving a focus signal from the signal output means or the full-range focus signal output means, changing the relative value of the stage and the objective lens 3 in the optical axis direction, and leading to the focus position; Focusing signal output switching means is provided that enables switching between the area fractional focusing signal output means and the full-range focusing signal output means depending on the depth of focus of the objective lens 3.Microscope using microscope autofocus detectorIt is.
[0019]
Specifically, the optical system of the microscope shown in FIG. 1 illuminates a subject (specimen) S placed on a stage 1 that can move in the vertical direction. And a transmission light source 2 'for speculum. The epi-illumination light from the epi-illumination light source 2 is reflected to the subject S side by the half mirror 22 arranged on the observation optical axis, and enters the subject S through the objective lens 3.
[0020]
The transmitted illumination light from the transmissive light source 2 ′ is reflected toward the subject S by the mirror 23 disposed below the stage 1, and illuminates the subject S from below through the optical path opening of the stage 1.
[0021]
The light beam from the subject S obtained by one of the light sources 2 and 2 ′ passes through the objective lens 3 and the half mirror 22 and enters the optical path branching member 24. A part of the light beam is guided to the eyepiece lens L by the optical path branching member 24, and the other light beam is guided to the imaging lens 4.
[0022]
The light beam that has passed through the imaging lens 4 is divided into two by the dividing prism 5, and the two divided light beams are incident on the light receiving surface of the CCD sensor 6 constituting the image pickup means in a parallel state. The two light beams incident on the CCD sensor 6 have different optical path lengths from the exit surface of the imaging lens 4 to the light receiving surface of the CCD sensor 6 due to the splitting prism 5.
[0023]
The front and rear optically conjugate positions (the front conjugate plane and the rear conjugate plane) of the imaging optical system including the imaging lens 4 are made to coincide with the light receiving surface of the CCD sensor 6. Accordingly, the subject image (front pin image, rear pin image) is projected onto the CCD sensor 6 at two positions conjugate to the planned image plane. These two subject images have the same shape when the subject S comes to the in-focus position.
[0024]
The CCD sensor 6 outputs an analog signal having a voltage corresponding to the amount of incident light and the accumulation time of the projected light image (front pin image, rear pin image). An analog signal from the CCD sensor 6 is input to the analog processing unit 9. The analog processing unit 9 performs analog processing such as amplification and filter processing separately on the front pin image and the rear pin image on the analog signal from the CCD sensor 6 and outputs the analog signal to the A / D converter 10. The output signal of the CCD sensor 6 digitized by the A / D converter 10 is stored separately in the memory 11 as a front pin image and a rear pin image.
[0025]
The arithmetic circuit 12 is divided into areas.contrastCalculation means and full rangecontrastComputation means, area proportion focus signal output means, and full-range focus signal output means are configured, and the contrast value of each subject S is calculated using digital signals of two subject images stored in the memory 11. . Then, a defocus amount indicating the degree of focus of the subject S is calculated from the contrast values of the two subject images, and the defocus signal is transmitted to the CPU 8.
[0026]
The CPU 8 monitors whether the analog signal of the subject image output from the CCD sensor 6 is compatible with the range of the analog processing unit 9 via the A / D converter 10. If the analog signal of the light image of the subject S is not compatible with the range of the analog processing unit 9, a command to set the charge storage time in the CCD sensor 6 to the storage time suitable for the range is transmitted to the timing generator 7. To do. The timing generator 7 inputs a read timing signal to the CCD sensor 6 with a charge accumulation time corresponding to a command from the CPU 8.
[0027]
Further, the CPU 8 constitutes a focus signal output switching means, instructs the arithmetic circuit 12 whether to divide the area based on the objective lens type (depth of focus), and based on the defocus signal from the arithmetic circuit 12 the subject. The movement amount and movement direction signals of the stage 1 for moving S to the in-focus position are calculated and transmitted to the drive circuit 13. The drive circuit 13 moves the stage 1 up and down based on a signal from the CPU 8 to adjust the focus.
[0028]
Further, an external controller 21 is provided for controlling the start / stop of the automatic focusing operation and the spectroscope or the magnification of the objective lens 3.
[0029]
The operation of the first embodiment configured as described above will be described with reference to FIG.
[0030]
When AF control is started by a signal from the external controller 21 (S1), the analog image signal of the front pin and the rear pin of the CCD sensor 6 is read (S2), and the analog signal of the CCD sensor 6 falls within the range of the analog processing unit 9. It is checked whether or not it is compatible (S3). If the range is not suitable, the timing generator 7 is instructed to set the accumulation time so that the range is suitable. This operation is performed until the signal from the CCD sensor 6 matches the range of the analog processing unit 9.
[0031]
When the range is suitable, the CPU 8 reads the focal depth or NA (numerical aperture) of the objective lens 3 currently being AF-controlled from the external controller 21 or the focal depth of the objective lens 3 from the external controller 21. From the NA information, the CPU 8 determines whether AF control by area division is necessary, and instructs the arithmetic circuit 12 (S5). When the NA of the objective lens 3 is small and the focal depth is large, the area division method is designated. When the NA of the objective lens 3 is large and the focal depth is small, the area division method is not designated. The arithmetic circuit 12 performs a predetermined calculation based on this command and calculates the defocus amount (S6, S7).
[0032]
Here, the selection of whether or not the CPU 8 uses the area division method for AF control is processed from the relationship between the optical path difference by the division prism 5, the projection magnification projected onto the CCD sensor 6, and the NA or the focal depth of the objective lens 3. That is, when the optical path difference and the projection magnification are constant, whether or not to perform the area division method is determined only by the NA or the focal depth of the objective lens 3.
[0033]
Further, the CPU 8 checks whether or not the in-focus state is obtained based on the calculated defocus amount (S8). If it is determined that the in-focus state is not in focus, the stage is driven according to the defocus amount (S9). If it is determined, AF control is terminated (S10). This operation is repeated until it is determined to be in focus.
[0034]
Here, the selection of the area division method based on the focal depth of the objective lens 3 and the defocus amount calculation unit, which are the features of the first embodiment of the present invention, will be described with reference to FIG.
[0035]
As described above, the CPU 8 determines whether or not to perform the AF control by the area division method based on the information of the objective lens 3 from the external controller 21 and instructs the arithmetic circuit 12. When the area division method is not selected (S20, 21), the arithmetic circuit 12 calculates the contrast value of the front pin image and the rear pin image from the signal from the CCD sensor 6 according to a predetermined evaluation function (S22, S23). Then, the difference between the rear pin contrast value and the front pin contrast value is calculated (S24), and the difference amount is output to the CPU 8 as the defocus amount (S25).
[0036]
On the other hand, when the CPU 8 selects AF control by the area division method, the arithmetic circuit 12 divides the front pin image into areas, calculates a front pin contrast value for each area (S26), and then divides the rear pin image into areas. The rear pin contrast value for each area is calculated (S27). After determining the contrast value of the front pin and the rear pin for each area, the difference between the rear pin contrast value and the front pin contrast value is calculated for each area of the corresponding front pin and rear pin area, and the defocus amount for each area is calculated ( S28). Further, after predetermined processing is performed from the defocus amount for each area, the total defocus amount actually used is determined and output to the CPU 8 (S25).
[0037]
That is, when AF control based on the area division method is selected, the contrast value is stored for each area, compared with the case where the area division method is not selected, the difference is calculated for each area, and the value is stored. The control and the control for performing the comprehensive determination increase as the area increases. As the control increases, the time required for the control also increases.
[0038]
Therefore, when it can be determined that the control by the area division method is unnecessary, according to the control of the embodiment of the present invention that does not use the area division method, the focus by the area division method is obtained when the area division is necessary. When accuracy is ensured and area division is not necessary, AF control can be performed by shortening the focusing time.
[0039]
In the embodiment of the present invention, the focusing operation is performed by driving the stage. However, the same effect as the present embodiment can be obtained even if the focusing operation is performed by driving the zoom or the infinite objective lens. .
[0040]
<Second Embodiment>
The optical system and system configuration of the AF apparatus of the present embodiment are the same as those in the first embodiment shown in FIG. 1, and the description thereof will be omitted. However, here, the differences are from the first embodiment. The area division control, which is a feature of the present embodiment, will be described with reference to FIG.
[0041]
When AF control is started by a signal from the external controller 21 (S30), analog image signals of the front and rear pins of the CCD sensor 6 are read (S31), and the analog signal of the sensor 6 conforms to the range of the analog processing unit 9. Is checked (S32). If the range is not adapted, the timing generator 7 is instructed to set the accumulation time so that the range is adapted. This operation is performed until the signal from the CCD sensor 6 matches the range of the analog processing unit 9.
[0042]
If the range is suitable, the CPU 8 reads the magnification of the objective lens 3 that is currently performing AF from the external controller 21 (S33). From the magnification information of the objective lens 3 from the external controller 21, the CPU 8 determines the number of pixels of the sensor 6 in one area (S34). When the number of pixels in one area is determined, the arithmetic circuit 12 divides the area by the determined number of pixels in the front pin image, and calculates a front pin contrast value for each area (S35).
[0043]
Next, similarly to the front pin image, the arithmetic circuit 12 divides the rear pin image into areas by the determined number of pixels, and calculates a rear pin contrast value for each area (S36). Further, the CPU 8 obtains a difference between the rear pin contrast value and the front pin contrast value for each corresponding front pin and rear pin area, and calculates a defocus amount for each area (S37).
[0044]
Further, after predetermined processing is performed from the defocus amount for each area, the total defocus amount actually used is determined and output to the CPU 8 (S38). The CPU 8 ends the process when it is determined that the total defocus amount is in focus based on the output from the arithmetic circuit 12 (S41), and when it is determined that it is out of focus, the total defocus is determined. The stage is driven based on the amount (S40). These operations are repeated until it is determined to be in focus.
[0045]
According to the configuration and control as described above, since the area is divided according to the magnification of the objective lens 3, noise images other than the subject image having a certain size such as dust and fingerprints attached to a slide glass, a cover glass, etc. The number of areas mixed in the subject image can be stabilized, and high-precision AF control can be performed.
[0046]
For example, FIG. 5 is a model showing the relationship between dust and areas, and (A) to (K) and (A) ′ to (A) ′ in FIG. 5 indicate areas by area division. Further, (a) and (a) ′ show models of the relationship between the area and dust when the objective lens magnification is 1 ×, and (b) and (b) ′ show the pixels in the area at the objective lens magnification 4 ×. A conventional model that is not variable according to the magnification is shown, and (c) and (c) ′ show the model of the present invention in which the pixels in the area are variable according to the objective lens magnification when the objective lens is 4 ×. That is, by changing the objective lens magnification from 1 × to 4 × with respect to FIGS. (A) and (a) ′, the number of pixels in the area of FIG. Yes.
[0047]
When the area where dust noise images are mixed is calculated from the model shown in FIG. 2, the number of areas in (a) is (c), (d) and 2, whereas in the case of the conventional area invariant (b) ), The number of areas where noise is mixed is similarly (c) and (d), and in the case of variable area according to the present invention, only (a) 'is 1.
[0048]
In the case of the conventional area invariant, the number of areas of (a), (c), and (d) is 3 for the number of areas 1 in FIG. It has become. Here, depending on the position of the dust, for example, if there is dust between (a) and (e), even if the area is variable according to the present invention, the number of noise mixed areas is 2, but the S / N in the area is The improvement is apparent from FIGS. 3 (c) and (c) ′.
[0049]
As described above, when the area is unchanged, the number of noise-introducing areas is increased. When the area of the present invention is variable, the number of noise-introducing areas can be reduced, and the S / N in the area can be improved. it can.
[0050]
Therefore, since the AF control according to the second embodiment of the present invention prevents the number of noise-containing areas from changing depending on the objective lens magnification, an increase in focusing time resulting from complicated control is suppressed, and the S / Since N is improved, the focusing accuracy is increased.
[0051]
<Third Embodiment>
Since the AF optical system and system configuration of this embodiment are the same as those of the first embodiment of FIG. 1, the description thereof is omitted, and here, the defocus amount by area division, which is a feature of this embodiment. The calculation method will be described with reference to FIG.
[0052]
When AF control by area division is started (S50), the arithmetic circuit 12 calculates the front pin contrast for each area by a predetermined calculation (S51). Further, the rear pin contrast for each area is calculated by a predetermined calculation (S52). Here, the contrast value for each area of the front pin and the rear pin is set to fCk (fC1,... FCn) and bCk (bC1, bC2,... BCn), respectively. n is the number of areas.
[0053]
Next, the arithmetic circuit 12 calculates a difference value Efk (Ef1, Ef2,... Efn) between the rear pin contrast and the front pin contrast for each area (S53).
[0054]
Further, it is checked whether Efk-1 and Efk have the same sign with respect to Efk (S56). If the same sign, Efk and Efk + 1 are further checked whether they have the same sign (S57). In the case of the same sign, Efk is stored in the memory as Efj (S58), and k is incremented. If not the same sign, k is simply incremented (S55). This operation is performed for the total number of areas (S54). That is, when the defocus direction of the two areas before and after the target area is the same as the target area, the operation of storing the target area in the memory as the effective area is performed for all the areas.
[0055]
After this operation is performed for all areas, the average value of the defocus amount in the effective area is determined as the defocus amount and output to the CPU 8 (S59, S60).
[0056]
By performing the control by area division as described above, it is possible to realize highly accurate AF in which noise components such as dust other than the subject image are removed.
[0057]
FIG. 7 shows a model in which dust adheres to the cover glass of the subject S. FIG. 4A is a cross-sectional view of a subject under AF control, and shows a state in which dust adheres to the target subject's cover glass between the slide and the cover glass. FIG. 7B shows a state in which the subject is projected on the sensor in the dust as shown in FIG. Further, (A) to (K) in the figure represent areas by area division. FIG. 4C shows the defocus direction for each area.
[0058]
In the state of FIG. 6A, the defocus direction for each area is as shown in FIG. 5C, and the defocus direction is reversed only in the area (D) where dust is present. According to the control of the present embodiment, the effective areas are (A), (F), (K), and (K), and it can be seen that the area of only the subject image is reliably used for the AF control. Therefore, highly accurate AF control can be performed by performing AF control from an image of only the subject image.
[0059]
Further, even when dust extends between areas as shown in FIG. 8, it is possible to perform AF using only the subject image as shown in (a), (ki) and (ku) in FIG. It is clear that even a thick subject S can maintain accuracy without changing from conventional AF.
[0060]
That is, if the area is optimized for dust, it is possible to reliably perform AF control using only the subject image.
[0061]
Therefore, even when dust or the like is mixed in the subject image, the subject S can be focused with high accuracy without hunting.
[0062]
<Modification of Embodiment of the Present Invention>
In the third embodiment, only the AF control based on the area division method has been described. However, if this embodiment is combined with the first or second embodiment, high-speed and high-precision AF control is achieved by a synergistic effect. It is clear that this is possible.
[0063]
The present invention is not limited to the first to third embodiments, and can be variously modified without departing from the gist of the present invention.
[0064]
【The invention's effect】
According to the present invention, high-speed and high-precision AF control can be realized even if a noise image such as dust exists in the subject image.Microscope automatic focus detection method, microscope automatic focus detection apparatus, and microscope using the sameCan provide.
[Brief description of the drawings]
FIG. 1 of the present inventionMicroscope automatic focus detection deviceThe block diagram which shows schematic structure of 1st Embodiment.
FIG. 2 is a flowchart for explaining the operation of the first exemplary embodiment of the present invention.
FIG. 3 shows selection and defocus of an area division method based on the focal depth of an objective lens, which is a feature of the first embodiment of the present invention
The flowchart for demonstrating a quantity calculation part.
FIG. 4 is a flowchart for explaining the operation of the second exemplary embodiment of the present invention.
FIG. 5 is a diagram for explaining the function and effect of the second embodiment of the present invention.
FIG. 6 is a flowchart for explaining the operation of the third exemplary embodiment of the present invention.
FIG. 7 is a diagram for explaining the function and effect of the third embodiment of the present invention.
FIG. 8 is a diagram for explaining the function and effect of the third embodiment of the present invention.
[Fig. 9] ConventionalAutomatic focus detection device used in microscopeThe figure for demonstrating the problem of.

Claims (6)

An objective lens;
An imaging optical system that captures an optical image of a copy placed on a stage through the objective lens and forms a subject image at a predetermined position;
An imaging means comprising a plurality of light receiving elements for reading a front pin image and a rear pin image formed at front and rear positions optically conjugate with respect to a predetermined imaging surface of the imaging optical system;
Area dividing means for dividing the imaging area imaged by the imaging means into a plurality of areas;
An area proportion focus signal output means for outputting a target focus signal from a focus state for each section of the optical image divided by the area dividing means;
Area variable means for varying the number of light receiving elements in each area in the area dividing means or varying the number of divisions of the imaging area according to the magnification of the objective lens;
A microscope automatic focus detection apparatus characterized by comprising: The area fraction focus signal output means includes:
Obtaining a focus signal using the other imaging area excluding the target imaging area when the difference value of the rear focus contrast and front focus contrast in two imaging areas before and after adjacent the target imaging area becomes opposite sign
2. The microscope automatic focus detection device according to claim 1, wherein : An objective lens;
An imaging optical system that captures an optical image of a copy placed on the stage through the objective lens and forms a subject image at a predetermined position;
Imaging means comprising a plurality of light receiving elements for reading a front pin image and a rear pin image formed at front and rear positions optically conjugate with respect to a predetermined imaging surface of the imaging optical system;
An area division function that divides an imaging area captured by the imaging unit into a plurality of areas, and an area proportion focus that outputs a target focus signal from a focus state for each section of the optical image divided by the area division function. A signal output function, and an arithmetic processing means configured to change the number of light receiving elements in each area in the area division or to change the number of divisions of the imaging area according to the magnification of the objective lens,
A microscope automatic focus detection apparatus characterized by comprising: The area fraction focus signal output function is
Before and after the target imaging area 2 When the difference value between the back pin contrast and the front pin contrast is opposite in one imaging area, the focus signal is obtained using the other imaging areas excluding the target imaging area.
Claims characterized in that Three The automatic microscope focus detection apparatus described. Claim 1 A microscope using a microscope automatic focus detection device, wherein the microscope automatic focus detection device according to any one of claims 4 to 4 is provided in a microscope. The optical image of the copy placed on the stage is taken in via the objective lens, and the subject image is formed at a predetermined position by the imaging optical system, and optically conjugated with the planned imaging surface of the imaging optical system. An area dividing function for reading a front pin image and a rear pin image formed at a front and rear position by an image pickup unit including a plurality of light receiving elements and dividing an image pickup area picked up by the image pickup unit into a plurality of areas, and the area division An area fractional focus signal output function that outputs a target focus signal from the focus state of each section of the optical image sectioned by function, and according to the magnification of the objective lens, A microscope automatic focus detection method characterized in that the number of light receiving elements in an area is variable or the number of divisions of an imaging area is variable .

Images