JP2004108805A - Optical measurement device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical measurement device adopting a measured sample holder allowing focusing on a measured sample in all measurable regions with the measured sample tightly attached to a placement plate even when a focus depth is very short with magnifying operation using an optical system. <P>SOLUTION: The optical measurement device comprises the sample placement plate through which a light from a lighting device arranged thereunder is transmitted and on the upper face of which the sheeted measured sample is placed, a compression vessel having an opening portion at the lower side for introducing compressed air to thrust the measured sample with static pressure and having an upper face formed of a transparent material, an air source for supplying the compressed air to the compression vessel, and an imaging device arranged above the measured sample. It is very effective for measuring a photographic film. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical measurement apparatus, and more specifically, to an optical measurement apparatus that employs a measurement sample holding apparatus that is flexible and easily deformed. More specifically, a sheet-like measurement sample having flexibility and being easily deformed and having a tendency to curl naturally, such as a photographic photosensitive material, is placed on a mounting plate and measured by an optical measuring device. In particular, the present invention relates to an optical measurement apparatus employing a measurement sample holding device capable of holding the measurement sample in close contact without lifting from the mounting plate.
[0002]
[Prior art]
Place a sheet-like measurement sample that is flexible and easily deformed at the same time as a photographic photosensitive material, etc., and that naturally tends to curl on a glass plate, and illuminate it from below. When optically measuring the transmitted light, the measurement sample tends to lift from the mounting plate. Therefore, in an optical measuring device in which the depth of focus is shortened due to a large enlargement in the optical system, the measurement sample is removed from the mounting plate. It must be held in close contact with the loading plate so that it does not float.
[0003]
For this reason, in the prior art, a sheet-like measurement sample is attracted and brought into close contact with the lower side of the loaded plate. However, in this method, since the measurement sample needs to be closely attached to the mounting plate at the position measured by the optical measuring device, the hole for sucking the measurement sample needs to be arranged near the measurement position. When the illumination light is applied from below, the illumination light is in a state different from the surroundings at the position of the hole for sucking the measurement sample, so that the measurable area cannot be widened.
[0004]
In order to eliminate such a defect, compressed air is blown from above the sheet-like measurement sample using an air nozzle (for example, Wind Jet Blow-off Nozzle Wind Jet manufactured by Spraying Systems Japan Co., Ltd.). The flattening method has been used. However, in this method, in the case of a flexible sheet-like measurement sample, the surface of the measurement sample undulates due to the flow of air to be blown, resulting in slight irregularities on the surface, and the center of the flow of air to be blown is Since it is strongly pressed and depressed, the depth of focus is very short, and when it is necessary to make it several tens of μm or less, it is said that the whole area of the measurable area cannot be brought into focus by this unevenness or depression. There was a problem.
[0005]
[Problems to be solved by the invention]
The present invention has been made in view of such circumstances, and the object of the present invention is to solve the above-mentioned problems and to greatly enlarge the depth of focus by greatly expanding the optical system. Even when the depth needs to be several tens of μm or less, the sheet-like measurement sample can be brought into close contact with the mounting plate, and the entire area of the measurement sample that can be measured can be focused. An object of the present invention is to provide an optical measuring device employing a measuring sample holding device.
[0006]
[Means for Solving the Problems]
In order to solve these problems, an optical measurement apparatus according to the present invention transmits a sample of a measurement sample in a sheet shape on the upper surface while transmitting illumination light from an illumination device disposed below. And a container having an opening on the lower side, which is disposed above the sample placement plate, introduces compressed air to press the measurement sample with static pressure, and has an upper surface formed of a transparent body. It has a crimping container, an air source for supplying the compressed air to the crimping container, and an imaging device arranged above the measurement sample.
[0007]
Here, the optical measurement apparatus according to the present invention includes a CCD camera that captures an image enlarged by the optical system and a storage device that stores data of the image captured by the CCD camera. Is preferred. Moreover, it is preferable that the contact surface with the said measurement sample of the said crimping | compression-bonding container is formed with the soft material.
Furthermore, the optical measurement apparatus according to the present invention is extremely effective when the measurement sample is a photographic film.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an optical measuring device of the present invention is explained based on a suitable embodiment shown in an accompanying drawing. Here, FIG. 1 is a diagram showing an embodiment of the optical measuring apparatus of the present invention.
[0009]
The optical measuring device 10 shown in the figure is a measuring device for measuring the image structure of a photographic film, for example, and in order to evaluate the photographic film, RMS granularity, Wiener spectrum, sharpness, MTF (frequency transmission) This is a device for measuring characteristics). As is well known, the photographic film to be measured here is flexible and easily deformed, and at the same time has a tendency to curl naturally. Therefore, the photographic film must be flattened and measured.
The optical measuring device 10 according to the present embodiment has a photographic film holding device that holds a measurement sample of a photographic film having such characteristics flatly. In the following description, a small area of the photographic film is measured. A case where the concentration is measured will be described as an example.
[0010]
The optical measuring apparatus 10 of the present invention places such a photographic film 12 as a sample to be measured on a glass sample mounting plate 14 and holds the photographic film 12 in close contact with the sample mounting plate 14. The density of a tiny portion of the photographic film 12 carrying an image is measured by the CCD camera 18 through the optical system of the imaging device 16 disposed above, and the entire optical measuring device 10 is measured. The basic configuration is almost the same as in the prior art.
[0011]
That is, illumination light is projected from the light source 20 disposed below the optical measuring device 10, reflected by the mirror 22, and projected toward the upper sample placement plate 14. As the light source 20, an arbitrary light emitter 24 such as an incandescent lamp or a fluorescent lamp can be used. When measuring the density of a minute portion of the photographic film 12, a halogen lamp is used, and a fly-eye lens is used for this. It is desirable to combine (not shown). The mirror 22 is preferably a concave condensing mirror.
[0012]
In the sample mounting plate 14, the illumination light is projected upward through the sample mounting plate 14 and the photographic film 12 as a measurement sample mounted thereon. Here, it is desirable for the sample mounting plate 14 to illuminate the photographic film 12 uniformly by disposing a diffusion plate on the surface in contact with the back surface (lower surface) of the photographic film 12 or forming a diffusion surface.
[0013]
The light transmitted through the sample mounting plate 14 and the photographic film 12 is imaged by the imaging device 16. This imaging device 16 has an optical system represented by a lens 26 and a CCD camera 18, and an image of the image structure of the photographic film 12 optically enlarged by the optical system is captured by the CCD camera 18. Is done. The image captured by the CCD camera 18 is stored as data in the storage device 28 as an electrical signal.
[0014]
The CCD camera 18 may be a two-dimensional still camera having 4 million pixels or more, or a scanner that scans images of the photographic film 12 and sequentially captures and stores them. Also good. The imaging device 16 is not limited to the CCD camera 18, and a normal still camera or video camera can be used, or an infrared or ultraviolet camera can be used depending on the measurement sample.
[0015]
On the upper surface of the sample mounting plate 14, there is provided a crimping container 30 for closely attaching the photographic film 12 to the upper surface of the sample mounting plate 14 via the mounted photographic film 12. The crimp container 30 is provided on a substrate 32 on which the sample mounting plate 14 is placed by a moving mechanism (not shown) so as to be able to be pressed and dissociated, and the photographic film 12 is placed on the upper surface of the sample placing plate 14. Is formed of a square box-shaped airtight container fixed in close contact with the photographic film 12 placed on the upper surface of the sample placement plate 14, and an opening is formed on the photographic film 12. An airtight chamber is formed by placing it downward.
[0016]
The opening is provided with a soft material seal 30 a that is in close contact with the photographic film 12 and hermetically seals the inside of the crimp container 30. This seal 30a is provided over the entire circumference of the opening, and has an affinity for rubber, silicone rubber, or the surface of the photographic film 12 so as not to affect the photosensitive material by contacting the photographic film 12. A soft plastic or the like having no adhesive is preferably used.
[0017]
In the above description, the description has been made on the assumption that compressed air does not leak from the crimping container 30, but even if a small amount of air leaks between the seal 30 a of the crimping container 30 and the photographic film 12, The air pressure fluctuates, or a large amount of air leaks from the gap between the seal 30a of the crimp container 30 and the photographic film 12, and this air flow may cause irregularities in the photographic film 12 around the gap. Unless otherwise, there will be no special problems.
[0018]
An introduction pipe 34 for introducing compressed air is provided on the side surface of the crimping container 30, and an air source 40 having an accumulator 36, a regulator 38, and the like is connected to the introduction pipe 34 and is crimped via a valve 42. Compressed air is supplied to the container 30. The valve 42 is preferably an electromagnetic valve, and it is desirable to supply compressed air to the crimping container 30 at a predetermined timing by the operation of the electromagnetic valve.
[0019]
A light transmitting window 30b formed of a transparent material such as glass is provided on the upper surface of the crimping container 30, and an image formed by light transmitted through the sample mounting plate 14 and the photographic film 12 is transmitted through the light. The image is picked up by the image pickup device 16 through the window 30b.
[0020]
In the above description, for example, the upper (upper surface) is used to describe the relative positional relationship, as described that the light source 18 is disposed below the sample mounting plate 14 and the imaging device 16 is disposed above. The word below is used. However, the upper (upper surface) and lower words describe the direction in which they are normally placed in order to clarify the light projection path. If the light projection paths are the same, this direction is used. It is not limited to description of.
[0021]
Since the optical measuring device 10 of the present invention is configured as described above, the photographic film 12 that is a measurement sample is captured on the upper surface of the sample mounting plate 14 when the CCD camera 18 of the imaging device 16 takes an image. The crimping container 30 is fixed to the upper surface of the crimping container 30 to fix the crimping container 30, and compressed air from the air source 40 is supplied to the inside of the crimping container 30 through the introduction pipe 34. At this time, since the crimping container 30 forms an airtight chamber by the soft material seal 30a and the photographic film 12 disposed in the opening of the crimping container 30, the photographic film 12 is statically applied to the upper surface of the sample mounting plate 14. Is pressed.
[0022]
In this way, since the entire surface of the photographic film 12 is pressed uniformly by pressing the photographic film 12 against the upper surface of the sample mounting plate 14 with static pressure, the photographic film 12 is completely applied to the upper surface of the sample mounting plate 14. It becomes possible to adhere to. In the experiments by the inventors, it was confirmed by measurement with a laser length meter that a flatness of 20 μm or less was obtained including the flatness of the upper surface of the sample mounting plate 14 and the thickness variation of the photographic film 12. It was done. This flatness of 20 μm or less is sufficient to measure the image structure of the photographic film 12. Further, it is obvious that higher flatness can be achieved by managing the flatness of the upper surface of the sample mounting plate 14 and the variation in the thickness of the measurement sample.
[0023]
The back surface (bottom surface) of the photographic film 12 has irregularities sufficient for air to flow out. However, when the back surface of the measurement sample is a completely smooth surface and is in close contact with the sample mounting plate 14, the air does not flow out. When there is a possibility, when the seal 30a of the crimping container 30 is pressed against the measurement sample, the back surface of the measurement sample and the top surface of the sample mounting plate 14 are in close contact with each other, so that the air cannot flow out. It is also conceivable that air remains between the plate 14. In such a case, the problem can be solved by forming a diffusion surface for diffusing the illumination light on the upper surface of the sample mounting plate 14 and making the diffusion surface rough enough to allow air to flow out.
[0024]
The illumination light projected from the light source 20 forms an image of the photographic film 12 by passing through the sample mounting plate 14 and the photographic film 12. This image is enlarged by an optical system represented by the lens 26, picked up by the CCD camera 18, and stored as data in the storage device 28. The data stored in the storage device 28 can be read out at an arbitrary timing. The data can be read out at an arbitrary time, for example, RMS granularity, Wiener spectrum, sharpness, MTF of the photographic film 12. It can be used for the measurement of etc.
[0025]
As described above, the optical measurement device according to the present invention is a small chamber that is disposed above the sample mounting plate and has an opening on the lower side, and introduces compressed air to statically measure the measurement sample. It is characterized in that the photographic photosensitive material is pressed against the upper surface of the sample mounting plate by a pressure-bonding container pressed in step 1, and various improvements and changes may be made without departing from the gist of the present invention. Needless to say.
[0026]
【The invention's effect】
As described in detail above, according to the present invention, in an optical measurement apparatus in which the depth of focus becomes very short by greatly enlarging in the optical system, and the depth of focus needs to be several tens of μm or less. Even if an optical measuring device has a very short depth of focus by enlarging with the optical system by pressing the sample with the static pressure of compressed air and bringing it into close contact with the sample mounting plate, the measurement sample is placed on the sample mounting plate. It is possible to realize an optical measurement device that employs a measurement sample holding device that can be brought into close contact with and can be focused over the entire measurable region of the measurement sample.
[Brief description of the drawings]
FIG. 1 is a diagram showing an embodiment of an optical measuring apparatus according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Optical measuring device 12 Photo film 14 Sample mounting plate 16 Image pick-up device 18 CCD camera 20 Light source 22 Mirror 24 Luminescent body 26 Lens 28 Storage device 30 Crimp container 30a Seal 30b Light transmission window 32 Substrate 34 Introducing tube 36 Accumulator 38 Regulator 40 Air source 42 Solenoid valve

Claims (1)

A sample mounting plate for transmitting the illumination light from the illumination device disposed below and mounting a sheet-like measurement sample on the upper surface;
A container which is disposed above the sample mounting plate and has an opening on the lower side thereof, which introduces compressed air and presses the measurement sample with static pressure, and has a top surface formed of a transparent body. When,
An air source for supplying the compressed air to the crimp container;
An optical measurement device comprising: an imaging device disposed above the measurement sample.

Images