JPH04217220A - Photometer device for microphotograph - Google Patents

Abstract

PURPOSE:To shorten photometric time largely, maintain high optical accuracy even with the weak light determine proper exposure with ease and at a high speed by determining a difference in a photoelectric transfer signal. CONSTITUTION:The image-formation of a sample 1 is made on the image surface of a lens 4, where the image is made to enter a photoelectric transfer element 10. At this time, a part of light which enters the photoelectric transfer element 10 is screened by a screening member 9. The screening member 9 is driven by a scanning means, by which the luminescent spot part of the image is screened and a position out of the luminescent spot is screened, and each of them is photoelectrically-transferred to be inputted into a calculating means 11. In the calculating means 11, the quantity of light of a part whose measuring range is bright is calculated according to a difference between a photoelectric transfer signal when the screening member 9 screens a part whose image is bright and a photoelectric transfer signal when the screening member 9 screens a part whose image is dark.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photometric device for microphotography used to determine exposure when taking microphotographs.

0002

[Prior Art] Microscopic photography is performed by selecting a specimen from a specimen with very low contrast under bright field illumination.
Determining the exposure time is extremely difficult because the specimens vary from fluorescence observation to a pitch-black background with scattered spots of light. For this reason, automatic exposure is almost impossible with the photometers used in ordinary cameras. On the other hand, when performing fluorescence observation, fluorescent specimens fade and cannot be stored, so there is a high demand for fluorescence photographs. Therefore, spot photometry, moving spot photometry, and the like are being considered as photometry methods that can be used for microphotography including fluorescence photography.

[0003] In the spot photometry method, a diaphragm having the size of the area to be photometered is placed on the image plane, and only the light from that area is photoelectrically converted and photometered. Thereby, it is possible to measure the light of a minute portion of an image and improve the accuracy. In order to photometer the amount of light in minute areas such as bright spots, the smaller the photometric range, the better the accuracy. Currently, 1% of the shooting surface
It is common to photometer an area of approximately

Furthermore, the moving spot photometry method facilitates photometry by moving a diaphragm or the like placed on the image plane to move the photometry site. With this method, when bright spots are scattered, such as in a fluorescent specimen, the photometric region can be aligned with the bright spots without disturbing the framing of the specimen.

Furthermore, recently, in ordinary cameras,
Multi-photometry has been considered in which the photometry section is divided into a plurality of photometry sections and the amount of light is calculated based on empirical rules from the brightness differences between the respective divided photometry sections. Normal cameras use this multi-metering to automate exposure compensation to handle backlight, black backgrounds, and white backgrounds. Note that in microscopic photography, it is extremely difficult to simply apply this multi-photometering method due to the diversity of photography conditions.

[0006]

[Problems to be Solved by the Invention] By the way, in order to make it even more user-friendly, it is desirable to further miniaturize the photometering part, and in reality, the photometering of an area of 0.1% of the photographing surface is required. requested. However, as the photometric region becomes smaller, it becomes difficult to align the photometric section of the device with the photometric position of the specimen, and there is a problem in that alignment takes time and photometry takes a long time.

In addition, in the above-mentioned spot photometry, one of the image planes
Since only the light from the photometric part, which has been miniaturized to about 10%, is photoelectrically converted, the photoelectric conversion signal that indicates the amount of light is at an extremely low level, and the photoelectric conversion output is buried in the inherent noise of the photoelectric conversion element, making photometry impossible. there is a possibility. In the above-mentioned spot photometry method, this becomes an even bigger problem when the photometry section becomes finer.

[0008]Also, as shown in Japanese Patent Publication No. 62-502427, it is possible to use a multi-view matrix such as an LCD as an aperture, but the transmittance is high when light is blocked and low when transparent. Therefore, there was a problem that the photometry accuracy decreased.

The present invention has been developed in view of the above-mentioned circumstances, and is capable of significantly shortening photometry time, maintaining high photometry accuracy even in weak light, and determining appropriate exposure easily and quickly. The purpose of the present invention is to provide a photometric device for microphotography that can perform the following steps.

0010

[Means for Solving the Problems] In order to achieve the above object, a photometric device for microphotography according to the present invention includes a photoelectric conversion element into which a light beam from a specimen to be measured is incident, the specimen and the photoelectric conversion element. A lens arranged on the optical path between the photoelectric conversion element and the photoelectric conversion element and forming an image plane in front of the photoelectric conversion element, a light shielding member arranged on the image plane of the lens and blocking light from a part of the photometric range, and the light shielding member A device comprising: a scanning means for scanning within the photometric range; and a calculating means for calculating the illuminance of the photometric section shielded by the light shielding member based on a photoelectric conversion signal output from the photoelectric conversion element. And so.

[0011]

According to the present invention, a specimen image is formed on the image plane of the lens, and this optical image is incident on the photoelectric conversion element. At this time, part of the light that enters the photoelectric conversion element is blocked by the light blocking member, and as this light blocking member is scanned by the scanning means, the bright spot part of the image is blocked, or the light spot is located outside the bright spot part. are shielded from light, photoelectrically converted, and input into the calculation means. The calculation means calculates the bright part of the photometric range based on the signal difference between the photoelectric conversion signal when the light shielding member blocks the bright part of the image and the photoelectric conversion signal when the light shielding member blocks the dark part of the same image. The amount of light is calculated.

[0012] Therefore, since the light is measured over almost the entire screen except for the part that is shaded by the light shielding member, there is no need to align the photometering section of the device with the photometering section of the specimen, and the photometry time is significantly reduced. In addition, since the amount of light from almost the entire screen is incident on the photoelectric conversion element, it is less susceptible to measurement errors due to fixed noise, etc., than when measuring only a spot portion.

[0013]

Embodiments Hereinafter, embodiments will be described with reference to the drawings.

FIG. 1 is a diagram showing an embodiment of the present invention, and shows an example in which the present invention is applied to a microscopic photographing apparatus. In this embodiment, light from a specimen 1 is taken into an objective lens 2, and a first image 3 of the specimen 1 is formed on the optical axis of the objective lens 2.
is formed. A second image is formed from this first image by a photographic lens 4, and a camera 5 is installed on the image plane. On the optical axis between the objective lens 2 and camera 5,
First and second beam splitting members 6 and 7 are arranged. The first light beam splitting member 6 acts to split the light beam from the specimen 1 into the photography side (camera 5 side) and the photometry side, and the second light beam splitting member 7 acts to split the light beam from the specimen 1 into the photography side (camera 5 side) and the photometry side. It acts to divide the image into a photography side and a microscope observation side.

On the reflection side (photometering side) of the first beam splitting member 6 when viewed from the specimen 1 side, a reduction lens 8, a scanning light shielding member 9,
The photoelectric conversion elements 10 are arranged on the same optical axis, and the scanning light shielding member 9 is arranged at the imaging position. An exposure control device 11 is connected to the photoelectric conversion element 10, and performs photometry calculations for minute areas based on the photoelectric conversion signal input from the photoelectric conversion element 10, and also uses the illuminance information obtained as a result and the information loaded in the camera 5. The film I
Determine the optimal exposure time based on SO sensitivity, etc., and release shutter 1.
Controls the opening and closing of 3.

On the other hand, a viewer 14 is arranged on the reflection side of the second beam splitting member 7 when viewed from the specimen 1 side, so that the specimen image can be observed. A frame 15 is provided in the viewer 14 so that the photographing range of the camera 5 can be confirmed.

As shown in FIG. 2, the scanning light-shielding member 9 is composed of a transmission matrix liquid crystal, and the orientation of the liquid crystal is controlled by an external drive, so that the light-shielding portion 9a is sequentially divided into each section. It is supposed to move to . Although the size of the light-shielding portion 9a depends on the resolution of the output of the photoelectric conversion element 10, it can be sufficiently set to about 0.1% of the entire image.

The exposure control device 11 accumulates the output of the photoelectric conversion element 10 for each section of the scanning light-shielding member 9, and calculates the amount of light in the light-shielding portion 9a by performing photometric calculations to be described later from this accumulated data. Next, the operation of this embodiment configured as above will be explained with reference to FIGS. 3 and 4.

In this embodiment, an image of the specimen 1 is captured by the objective lens 2, reflected by the first beam splitting member 6, passed through the reduction lens 8, and imaged onto the scanning light shielding member 9. Here, as an example of a sample image, as shown in FIG. 3(a), the background B is dark and the bright spots T are scattered therein. Scanning of the photometric range with respect to this sample image is performed by using the scanning light shielding member 9 as shown by the arrow in FIG.
The entire surface is scanned by moving the light-shielding portion 9a horizontally one section at a time and sequentially shifting it downward. In the exposure control device 11, the light shielding portion 9a accumulates the photoelectric signal output from the photoelectric conversion element 10 every time the light shielding portion 9a moves by one section.

Here, as shown in the figure (c), when the light-shielding part 9a is located at a position away from the bright spot T of the sample image, and as shown in the same figure (d), the light-shielding part 9a is in a position away from the bright spot T. There is a difference in the amount of light incident on the photoelectric conversion element 10 when the photoelectric conversion element 10 is in the position covering the photoelectric conversion element 10 . By determining this light amount difference, the light shielding portion 9
The amount of light at the bright spot T that is blocked by point a can be determined. Therefore, the amount of light only in the light-shielding portion 9a is determined.

The accumulated data accumulated in the exposure control device 11 is shown in FIG. 4(a). In addition, in FIGS. 4(a) to 4(c), the horizontal axis shows the illuminance which is the photoelectric conversion output, and the vertical axis shows the number of corresponding sections. When the specimen image shown in FIG. 3(a) is scanned, two peaks P1 appear as shown in FIG. 4(a).
, P2. The first peak P1 and the second peak P1
The difference between the peaks P2 indicates the amount of light at the bright spot T portion blocked by the light shielding portion 9a, and the area ratio between the first peak P1 and the second peak P2 indicates the area ratio of the bright spot T portion. Note that the photometric calculation for determining the illuminance of the bright spot T portion includes a method other than the method of determining the illuminance of the shaded portion 9a (bright spot T) from the light amount determined from the difference between the first peak P1 and the second peak P2. Another method includes dividing the light amount of the second peak P2 by the area of a bright portion obtained from the area ratio of the first and second peaks P1 and P2. Further, when the light shielding member 9 has a certain degree of transmittance α, the accurate light amount can be calculated by dividing the light amount difference by the transmittance α.

Note that FIGS. 4(b) and 4(c) show accumulated data of other samples. In the case of the image shown in FIG. 6B, the illuminance distribution shows the first and second peaks P3 and P4, as described above. In this example, the first peak P3 with low illuminance is significantly higher. This indicates that the specimen has a bright background and dark areas within it. In addition, in the case of the image shown in FIG. 4(c), only one peak exists. This indicates that the illuminance distribution of the sample is uniform.

The exposure control device 11 determines the illuminance distribution on the specimen by taking statistics of the output change of the photoelectric conversion element 10 for each cycle of image scanning from the accumulated data, and based on this illuminance information and film information. Determine exposure time. The determined exposure time is set in the drive device 12, and the shutter 13 is controlled to open and close using this exposure time.

As described above, according to this embodiment, an image plane is formed in front of the photoelectric conversion element 10, and the scanning light shielding member 9 made of a transmission matrix liquid crystal is arranged on this image plane, so that the inside of the screen can be seen. The light-shielding portion 9a is scanned to capture the photoelectric conversion signal at this time, and the brightness of the portion covered by the light-shielding portion 9a is determined from the difference between the photoelectric conversion signal in that state and the photoelectric conversion signal in other states. Therefore, it is possible to photometer the illuminance of an area of 0.1% of the image, which is the size of the light shielding part 9a, and
Since it is possible to measure the entire area of the screen, excluding the light-blocking areas, the amount of light can be dramatically increased compared to metering only spot areas, and measurement errors due to fixed noise are less likely to occur, greatly improving measurement accuracy.

[0025] In addition, when using a transmissive liquid crystal plate in the conventional method, the transmittance at the time of shielding the light was a problem, but according to this embodiment, the transmittance at the light shielding part is as large as the conventional method. Even so, if there is a difference in transmittance between the light-blocking portion and the transmitting portion, the true illuminance can be determined by performing photometric calculations taking the transmittance into account.

Furthermore, since the light-shielding portion 9a formed by the transmission matrix liquid crystal moves over the entire image area, the appropriate exposure can be determined without aligning the photometering section of the device with the photometering position of the specimen, which reduces the time required to determine the appropriate exposure. can be significantly shortened.

Note that other photometric methods can also be applied to the apparatus having the above configuration. For example, the scanning light shielding member 9 made of a transmission matrix liquid crystal is controlled so that one section of the photometry section is transmitted and light shielded, and the other portions are kept in a transmitting state. Then, the illuminance of one section to be reduced is determined from the difference in the amount of light between when the light is transmitted and when the light is blocked. That is, conventional spot photometry can also be performed. Further, the shape of the section can be easily changed by electrical processing, and in this way, the photometric portion can be freely selected.

FIG. 5 shows another scanning light shielding member 30 that can be used in the above embodiment. This scanning light shielding member 3
0, the light shielding members 19a are arranged at equal angles on the circumference of the transparent glass disk 20, and the fan-shaped diaphragm 21 is arranged opposite to an arbitrary position on the circumference of the transparent glass disk 20.

When photometry is performed using this scanning light shielding member 30, the transparent glass disk 20 is rotated and the light shielding member 19 is
The inside of the fan-shaped diaphragm 21 is scanned as a photometric range at step a. The light shielding member 19 takes one rotation of the transparent glass disk 20 as one cycle.
The output of the photoelectric conversion element 10 is captured at a sampling time equal to or less than the value obtained by dividing the tension angle a by the rotational angular velocity of the transparent glass disk 20. If such a scanning light shielding member 30 is used in the above embodiment, the transmittance of the light shielding part is low and the transmittance of the transmitting part is high, so there is an advantage that photometry can be performed even with weak light.

[0030]

[Effects of the Invention] As detailed above, according to the present invention, the photometry time can be significantly shortened, high photometry accuracy can be maintained even in weak light, and appropriate exposure can be easily and quickly determined. It is possible to provide a photometric device for microphotography that can perform

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of an embodiment of the present invention.

FIG. 2 is a plan view of a scanning light shielding member used in one embodiment.

FIG. 3 is an explanatory diagram of the operation of one embodiment.

FIG. 4 is a diagram showing the illuminance distribution of accumulated data according to the sample.

FIG. 5 is a plan view of another scanning light shielding member used in one embodiment.

[Explanation of symbols]

1...Specimen, 2...Objective lens, 4...Photography lens, 8...
Reduction lens, 9... Scanning light shielding member, 10... Photoelectric conversion element,
11... Exposure control device, 13... Shutter.

Claims (1)

[Claims] 1. A photoelectric conversion element into which light from a specimen to be measured is incident, and a lens arranged on an optical path between the specimen and the photoelectric conversion element and forming an image plane in front of the photoelectric conversion element. a light shielding member disposed on the image plane of the lens to shield a part of the photometric range; a scanning means for scanning the photometric range with the light shielding member; and a photoelectric conversion signal output from the photoelectric conversion element. A photometric device for photomicrographs, comprising: calculation means for calculating the illuminance of the photometric portion shielded by the light shielding member based on the above.