JP2020012652A - Lens checker - Google Patents

Abstract

To provide an imaging type lens checker that not only achieves miniaturization as an observation or inspection device of an inspected lens, but also can readily and surely perform a human discrimination or observation of a shallow scratch, tiny scratch, dust, striae and the like hard to be optically grasped in the inspected lens without using expensive and mechanical computation processing means and the like.SOLUTION: A lens checker is configured to: freely perform an operation of moving pinhole type stop means on a transmission light-purpose light source side of an inspected lens relatively to an inspected lens loading table by a prescribed dimension; oppositely arrange imaging means in a co-axial relationship with the light source side; provide light-shield switch means 8 that has knife edges 8a and 8b located in an optical path of the imaging means, and can alternatively shield a half of a field of view; apply coloring processing different in hue to an obtained parallax image; and obtain a synthesis parallax image.SELECTED DRAWING: Figure 5

Description

INDUSTRIAL APPLICABILITY The present invention is used as an apparatus for observing hidden marks and the like, in addition to inspecting the appearance of scratches, dirt, and dust on the surface of a lens to be inspected such as spectacle lenses, contact lenses, and other optical lenses. The so-called lens checker.

For a spectacle lens or contact lens in use, a person using a lens checker that is configured to visually identify foreign matter such as scratches, dirt, dust and dirt on the front and rear surfaces of the lens from the image of the light receiving screen or imaging screen. In the case of visual observation or inspection, the following various problems exist.
First, in the case where the lens to be inspected has a deep and large scratch, or a foreign matter such as a large dust or dust, the ratio of refraction or reflection of the transmitted light transmitted through the scratch or dust is large. In contrast, it is relatively easy to catch light, but in the case of shallow and small scratches or small dust, it is difficult to optically catch refracted transmitted light or reflected reflected light. This makes it impossible to visually discriminate or observe an image based on the detected slight light, and at the same time, the level of image data based on the detected light is reduced, making the mechanical discrimination itself more difficult. At present, there has been a long-awaited need for improvement measures for such shallow scratches, small scratches, and garbage.
In addition, for an optical system such as a collimator lens on the light source side, an imaging device and a screen on the light receiving side are:
The general configuration is to increase the outer diameter of the lens to increase the light receiving range.In particular, the tendency of the optical system to increase in diameter is that the site of the foreign substance present on the lens to be inspected is not specified. Together,
In general, hidden marks and alignment marks are generally engraved near the periphery of the lens to be inspected, so avoid increasing the diameter of the optical system so that the entire lens to be inspected can be covered. Tend not to be.
In particular, even in the case where a hidden mark or alignment mark is made visible by using a stop as a schlieren optical system on the light source side, the collimating lens optical system or the cover for refracting the emitted light from the light source and emitting the light. In order to ensure that the transmitted light is received by the inspection lens and the light receiving side, it is necessary to adopt a relatively large-diameter optical system as described above for the collimating lens and the light receiving side lens. Therefore, the size of the lens checker is unavoidable, and at present, there is an inconvenience which is a bottleneck in downsizing the apparatus.

Further, in the case of a conventional imaging lens checker in which imaging means such as a CCD camera is provided on the light receiving side, scattered light from a light source is irradiated as a backlight of the lens to be inspected, and the lens to be inspected is bright-field illumination or dark-field illumination. Illumination is used to make scratches stand out, but in particular, the diameter of the optical system on the light receiving side that receives scattered light is inevitable, and at the same time, scratches, dirt, and hidden marks observed in a dark or bright field state In order to determine whether a lens or a foreign substance is present on the front surface or the rear surface of the lens, a focus adjustment operation (focusing) between the front surface image and the rear surface image of the lens must be performed each time to re-capture the image. It was accompanied by annoyance. The present applicant has already filed a separate patent application (Japanese Patent Application No. 2017-224756) to solve this inconvenience.
On the other hand, rather than relying on human visual observation of the captured image, the normal part of the lens to be inspected and the distinction between a scratch and a foreign substance are captured as light intensity distribution or luminance distribution using the captured image data, and are mechanically determined or In order to make a determination, a luminance sensor and an arithmetic processing unit for mechanically processing data are required, so that the optical device becomes complicated, and the cost of the arithmetic processing unit increases and becomes expensive. It was inconvenient.

As described above, the lens checker is a lens checker for visually observing the object, and includes the light emitting diode 5, the pinhole plate 6, and the collimator lens 7 for observing the lens L to be inspected.
Japanese Patent Application Laid-Open Nos. H11-150686 and 2004-209686 disclose a prior art example in which imaging means such as a large-diameter projection screen 4 or the like arranged in a coaxial relationship with each other is provided so as to visually observe a shadow image or a shadow image output screen on the screen 4. Further, an illumination unit 120 integrated with the diffusion plate 20 for observing the lens 5 to be inspected is provided so as to be coaxially adjustable with respect to the CCD camera 30 and the like arranged opposite to each other so that the lens 5 is transmitted through the lens 5. For example, Japanese Patent Application Laid-Open No. H11-150572 discloses a prior art in which a luminance distribution related to the light intensity of transmitted light is measured from the obtained image data, and the luminance and the like are numerically converted into numerical values and subjected to a comparison operation to mechanically determine a scratch or a foreign substance. It is known, but none of them can solve the problem of discrimination accuracy for shallow scratches, small scratches, dust, and the like.
JP-A-10-132707 JP-A-9-269276

A first problem to be solved in the present invention is to use a hue that is significantly different in color from a parallax image to enable visual discrimination of shallow scratches, small scratches, small dust, and the like. By obtaining an image with a change, it is possible to provide a superior lens checker that can easily and surely make a human distinction and observation easily by making the shallow scratches, small scratches, dust, and the like stand out in color. More preferably, when a combination of different hues is adopted as a hue having a complementary color relationship, a gray scale can be obtained as a complementary color harmony to enable a remarkable discrimination.
Further, as in the cited document 1, a further problem in the present invention is that a pinhole type aperture means for restricting irradiation light from a light source to an optical axis center light beam, and a restricted optical axis center light beam as a parallel light beam. There is no significant difference in achieving the so-called Schlieren effect by using a collimating lens to illuminate the test lens with a parallel light beam to enhance the image due to the transmitted light from the test lens, but the difference is the light source. By arranging the collimating lens unit of the irradiation light on the side to be slidable relative to a predetermined dimension in the horizontal direction perpendicular to the optical axis, the outer diameter position of the irradiation range of the transmitted light can be changed and adjusted appropriately. None, the transmitted light flux bent at the periphery of the lens to be inspected is controlled to be able to be received at the light receiving side, and the increase in the diameter of the collimating lens is suppressed. It possible to diameter of together also a large diameter side optical system,
An inexpensive optical system such as a large-diameter screen (or CCD camera) on the light-receiving side as described in the cited document 1 can be achieved, and the entire lens checker can be downsized. An object of the present invention is to provide a lens checker of a human observation type.
Still another object of the present invention is to replace a luminance sensor required for mechanical judgment and an expensive arithmetic processing unit for digitizing image data as described in Patent Document 2 with a simple light amount adjusting unit and a light shielding unit for an image pickup optical system. A parallax image is obtained by adding a switching mechanism, the sharpness of the image can be improved at a low cost, and furthermore, an image that is distinguished in color by utilizing a color tone change caused by overlapping of different hues together with the obtained parallax image. It is another object of the present invention to provide a lens checker having a new function capable of performing a discrimination by using a function.

At the center of the upper surface of the base provided with the pinhole type aperture means arranged coaxially with the transmitted light source for the test lens, a mount for the test lens is provided, and the mount for the test lens is provided. While the collimating lens is arranged coaxially with respect to the penetrating optical axis, the surface of the lens to be examined is coaxially arranged with the light source at the upper end of a column erected on one side of the base. Alternatively, an objective lens for forming an image of the back surface, an imaging lens, and a light receiving side optical system including an image pickup unit are arranged to face each other, and an optical light receiving path is provided in an optical path of the image pickup unit constituting the light receiving side optical system. A light-shielding switching means, in which a knife edge is located at the center of the optical axis of the range and which can alternately shield half of the field of view, is provided so as to be able to advance and retreat in the same plane along an axis orthogonal to the optical axis. For parallax image data, A color processing unit for performing hue image processing having a different hue relationship and a synthesis processing unit for the color-processed image are provided, and a composite image formed by these components can be displayed on a screen as a new parallax image. It is characterized by the following.

Further, the collimating lens is coaxially arranged with respect to the optical axis passing through the lens mounting table at the center of the upper surface of the base according to the present invention, and is slidably movable relatively in a direction perpendicular to the optical axis. The collimating lens is slightly moved to operate so that the irradiation position of the transmitted light on the lens to be measured can be moved and irradiated to a predetermined position of the lens to be measured.

In the lens checker of the present invention, a mounting base for the test lens is provided at the center of the upper surface of the base provided with the pinhole type aperture means arranged coaxially with the transmitted light source for the test lens, While arranging the collimating lens coaxially with respect to the optical axis passing through the test lens mounting table,
At the upper end portion of a column that is erected on one side of the base, an objective lens and an imaging lens for capturing an image of the front surface or the back surface of the test lens so as to be coaxial with the light source, The light receiving side optical system comprising the image pickup means is disposed to face, and in the optical path of the image pickup means constituting the light receiving side optical system, a knife edge is located at the center of the optical axis of the optical light receiving range, half of the field of view, For example, light-shielding switching means capable of alternately blocking the right half and the left half is provided so as to be able to advance and retreat in the same plane along the axis orthogonal to the optical axis, and different hue relations to the parallax image data by the imaging means are provided. The colorimetric processing means for performing the hue image processing and the synthesizing means for the colorized image are provided so that these composite images can be displayed on the screen as a new parallax image. Lens surface For an image focused on one of the back surfaces, the position of the image of the foreign matter such as small dust or dust floating from the front or back surface of the lens is shifted from the optical axis position according to the original size of the foreign matter of dust or dust. An image is formed at a slightly eccentric position,
Since this can be observed as a parallax image, an image of a foreign substance such as dust or dust is displayed as a parallax image in which a double shift has occurred, as compared with an image of a scratch on the front surface (back surface) of the lens to be inspected. By obtaining, as a new parallax image, a composite image of a color-processed image with a different hue for each half of the parallax image data, even if there are shallow flaws, small flaws, dust, and the like, the overlapping parts due to parallax deviation are synthesized. The color tone can be made to stand out with a high degree of accuracy, so that the determination can be made easily and accurately by humans, and there is no need to use a luminance sensor or expensive arithmetic processing means, so that it is inexpensive and reliable. An excellent practical effect of performing discrimination or observation can be exerted.
Note that the different hues to be colorized include so-called complementary colors that are opposed to each other in the hue circle of light or a relationship approximated to the complementary colors. It is needless to say that the discrimination effect is excellent because the color tone to be reproduced becomes a remarkable color tone as a pseudo-color gray scale.

Further, the lens checker of the present invention arranges a collimating lens coaxially with respect to an optical axis penetrating a test lens mounting table provided at a central portion of the upper surface of the base, and relative to the optical axis in a direction orthogonal to the optical axis. It is arranged so that the slide movement can be freely adjusted, and by slightly moving the collimating lens, the irradiation position of the transmitted light on the test lens is configured to be movable and irradiable to a predetermined position of the test lens. Even if the irradiation light from the light source is refracted by the pinhole type aperture means, the small-diameter collimating lens is slightly moved in the horizontal plane, for example, in the left-right direction (or the front-back direction), so that the lens to be inspected can be widened Can be irradiated.
The transmitted light that has passed through the lens to be inspected may not enter the light receiving portion due to the front and back shapes, materials, refractive indexes, and the like of the lens. However, there is an adjustment mechanism that allows the light to enter by a slight movement of the collimating lens unit.

Furthermore, since the imaging type lens checker of the present invention is provided with a knife edge in the same plane as the light shielding switching means, when the optical light receiving range is, for example, a circular visual field, one (right half) ) Can be shielded from each other so that the transmitted light of the other (left half) does not interfere with the image of (1), so that the image of each semicircle can be captured as a clear image. An excellent effect of obtaining a clear image of a foreign substance and significantly improving the accuracy of human reading and discrimination of an observed image is also exhibited.

1 is a perspective view showing an embodiment of the overall configuration of a lens checker according to the present invention. Longitudinal sectional view for explaining the main body of the lens checker of the present invention. 1. Enlarged sectional view of a base portion viewed from the direction of arrows AA in FIG. Optical diagram for explanation in the lens checker of the present invention Explanatory diagram showing the relationship between the light-shielding switching unit and the color complementary color processing unit in the lens checker of the present invention. Explanatory diagram of the principle of parallax in the lens checker of the present invention An example of a monochrome version of a photographed image in the lens checker of the present invention

An embodiment of the lens checker of the present invention will be described with reference to the drawings.
First, in FIG. 1 showing the entirety of the lens checker of the present invention, at the center of the upper surface of the base 1,
A diaphragm plate 2a as a diaphragm means having a pinhole 2b of about 50 microns perforated at the center with respect to the irradiation light from the built-in transmitted light source 2 is provided close to and coaxial with the light source 2, for example. The illumination light from the pinhole 2b is given a predetermined refraction angle with respect to the optical axis and passes therethrough, and the collimating lens unit 4 (see FIGS. 2 and 3) on the inner side of the lens Le on the lens mounting table 3 to be described later. ) Is configured to be irradiated as parallel light.

In one embodiment of the present invention, as described in detail in FIGS. 2 and 3, an operation dial 1a for adjusting the light amount of the light source 2 is provided on the base 1 of the lens checker main body. The transparent glass plate 3a for mounting the lens to be tested is provided in a coaxial relationship with the light source 2.
In the case of the illustrated embodiment, for example, a test lens mounting table 3 mounted on the top of a black cylindrical plastic cylindrical body 3b is arranged in a cantilevered support state by a support arm member 3c. The mounting table 3 is attached so as to be movable at least vertically in the same axis along the optical axis by, for example, manually operating the adjusting knob 3d of the cantilever support section. The focus position is configured to be changed and adjusted appropriately.
The focusing operation by the vertical movement operation of the lens mounting table 3 is performed in such a manner that when observing the front surface or the back surface of the lens to be inspected, the lens is once focused on one lens surface, and then the light receiving side is described later. This is a convenient mechanism for focusing on the other lens surface by operating the adjustment knob 3d without changing the general focus of the imaging unit 9.
Further, the transparent glass plate 3a for mounting the test lens and the plastic cylindrical body 3b are not limited to a circular or cylindrical shape, and for example, a quadrangular one is used to constitute the test lens mounting table 3. Needless to say, it is good.

Further, a feature of the present invention is that a certain gap is coaxially formed between the cylindrical body 3b and the cylindrical body 3b of the cylindrical body 3b of the lens mounting table 3 with respect to an optical axis passing through the cylindrical lens mounting table 3. While keeping the collimated lens unit 4 for irradiation light, which is composed of a group of condenser lenses 4a, 4b, and 4c having a relatively small diameter, for example, and the collimated lens unit 4 is a slide type horizontally provided on the base 1. The guide member 4d is supported in the air in the cylindrical body 3b in a cantilevered support state, and the adjusting knob 4e attached to the support portion is manually screwed to operate.
When viewed from the front of the apparatus, for example, in the horizontal direction of the left and right (or front and rear) with respect to the base 1 within a predetermined dimension, that is, in accordance with the dimension allowed in the fitting gap with the inner surface of the cylindrical body 3b, the illustrated embodiment is relatively illustrated. In the case of (1), since the light beam is slightly movable while maintaining the horizontal relationship in the left-right direction, the irradiation light refracted by the pinhole effect of the aperture plate 2a by this relative movement operation is used as the collimating lens unit 4. 4 can be irradiated as parallel light without deviating from the lens Le to be measured (FIG. 4).
And the moving operation mechanism can receive the transmitted light beam bent by the lens to be detected on the light receiving side, which is advantageous in the case of a high-curve lens, for example, and at the same time, it is advantageous for the whole device. This enables miniaturization.

On the other hand, as shown in FIG. 2, the transparent glass plate 3a of the mounting table 3 is placed on the upper end of the support 5 planted on one side of the upper surface of the base 1 in a coaxial relationship with the light source 2 for transmitted light. An imaging lens comprising an objective lens 6a and imaging lenses 6b, 6c, 6d in an overhang state of an imaging means 9 (for example, CMOS or the like) for imaging an image by a light beam transmitted through the lens Le to be inspected. It is supported together with the unit 6, and the image data obtained by the imaging means 9 is enlarged and displayed on a display screen 13 of a personal computer or a tablet connected by a cable 10, and this screen 13 is observed or inspected by human. These configurations are the same as those of the conventional imaging type lens meter, and the collimating lens unit 4 is horizontally aligned on the base inside the mounting table 3 described above. Manner that it is slidably movable in construction, and except for obtaining a parallax image obtained by the imaging unit 9 as a combined parallax image by the color processing of a different hue such as described below with each other, a large difference is not.
In the figure, reference numeral 9a denotes an operation knob for finely adjusting the focus of the imaging means 9.

As one of the major features of the present invention, as shown in FIGS. 4 and 5, the irradiation light from the irradiation light source 2 is refracted by the pinhole effect of the aperture plate 2a. Irradiation is performed from the back surface of the mounting table 3 via the collimating lens unit 4, whereas an image forming lens is formed as a lens surface image or a back image by parallel light transmitted through the test lens by the objective lens 6 a facing the mounting table 3. In a basic optical system that guides the image to the unit 6 and forms an image on the imaging unit 9, the amount of light can be adjusted in the optical path before the imaging unit 9, for example, by continuously narrowing and changing the optical path area. The iris diaphragm type variable diaphragm means 7 and the knife edges 8a and 8b are located at the center of the optical axis of the optical receiving area so that half of the field of view can be alternately blocked in the same plane (for example, When the optical field of view is circular as in the embodiment of FIG. 5, the right and left semicircular portions are blocked, but within the plane of the same optical field of view, every half in the front-back direction when viewed from the apparatus main body. The light-shielding switching means 8 is provided so as to be able to advance and retreat along an axis orthogonal to the optical axis, so that the imaging means 9 can capture left and right parallax images. The parallax image data obtained under the intervention of the knife edges 8a and 8b is transmitted to the image coloring processing unit 11 via the cable 10 as shown in FIG. In the coloring processing units 11a and 11b having different hues of equal left and right, for example, the present invention is not limited to the complementary color relationship in the hue circle of light as in the embodiment of the present invention. As an example, red (11a) and green (11b) colorization processing is performed on each parallax image, and these colorized parallax images are superimposed by the synthesis processing unit 12 as a new synthesized parallax image. The composite image is transmitted to the display 13 to be enlarged and displayed in color. However, in this embodiment, an example is shown as a monochrome image in FIG.

That is, as shown in FIG. 5, the light-shielding switching means 8 of the present invention is arranged so that the right half and the left half of the optical field range are shielded by the knife edges 8a and 8b, respectively. Along the axis perpendicular to the optical axis 6, any one of the knife edges 8a or 8b of the light-shielding switching means 8 is selectively operable to enter and exit the optical path, and any one of the knife edges 8a and 8b is provided. The transmitted light flux whose central light flux is blocked by the light source is prevented from interfering with the transmitted light flux on the unblocked side to affect the diffraction image, so that clear parallax images can be obtained. Thus, not only is it possible not only to use an expensive arithmetic processing means but also to easily and inexpensively perform the visual discrimination and observation between the intended scratch and dust or dust, and in particular, it is particularly advantageous. Was By applying a different hue coloring process to the difference image, even if it is a shallow flaw, a small flaw, dust, or the like, the color tone of the image superimposed by parallax becomes prominent as a new color tone synthesized. It can be easily determined.
In particular, when the different hues are close to the complementary color relationship in the light hue circle as in the present embodiment, for example, when a red and green colorization process is performed, the color tone different from the composite color of these red and green Is a color tone close to a gray scale and presents a color tone that is easily distinguishable in color, so that a so-called complementary color harmony merit that the discrimination or observation becomes easy can be obtained.
In the case of the above-described embodiment as different hues, a case where the red processing unit 11a and the green processing unit 11b which are close to the complementary color relationship is used is illustrated, but the combination of different hues is not limited to the complementary color relationship. Needless to say, as the color conversion method, any method such as using the simplest mechanical color filter or using an electric processing filter or a color conversion method is adopted. As long as it does not depart from the gist of the present invention,
A person skilled in the art can freely select.

Further, in the embodiment of the present invention, the light-shielding switching means 8 having the knife edges 8a and 8b is provided with an iris capable of continuously changing and adjusting the optical path area by operating, for example, a diaphragm knob 7a or a dial (not shown). An aperture type variable aperture means 7 is integrally provided, and the variable aperture means 7 is selected in an optical path along an axis orthogonal to the optical axis of the imaging lens unit 6, similarly to the light shielding switching means 8. The brightness of the image can be freely adjusted by the aperture adjustment effect on the imaging means 9 so that the discrimination between the scratch of the lens to be inspected and the hidden mark can be easily performed by human. That is, it is configured to be able to
The variable aperture means 7 and the light-shielding switching means 8 provided with the knife edges 8a and 8b may be individually provided without being combined integrally and operated individually, but may be integrally configured. It is preferable to perform the switching operation procedure without fail, and it is preferable to change the manual operation to an automatic operation method or the like without departing from the basic objects and effects of the present invention. May be adopted. Also, the form of the variable aperture means 7 is not limited to the embodiment.

Hereinafter, the operation procedure and observation procedure of the lens checker of the present invention will be described with reference to the accompanying drawings.
In the lens checker of the present invention, when starting the inspection or observation of the lens to be inspected, first, the lens to be inspected Le (whether it is a round lens or a lens with a spectacle frame) is placed on the upper surface of the lens mounting table 3 of the base 1. The image data of the transmitted light from the lens Le to be measured is photographed by the image pickup means 9 while adjusting the light amount of the irradiation light source 2 by the operation dial 1a. It is displayed on the screen, and the internal defect of the lens to be inspected and the surface scratches and hidden marks, or the scratches, dust or dirt, etc. are manually observed and inspected, but in the case of the former surface scratches and hidden marks etc. The operation procedure and observation procedure are almost the same as those of the conventional one, and the brightness of the image is adjusted by operating the variable aperture means 7 or dialing (either manually or automatically). And adjust the sharpness and observe.

What is important here is that, in the case of the present invention, as is clear from the optical diagram shown in FIG. 4, even if the irradiation light is refracted due to the pinhole effect in the diaphragm plate 2a, the peripheral portion of the lens to be measured is not affected. Can be applied without deviating from the collimated light. More specifically, the optical system on the irradiation light side such as the collimating lens unit 4 and the optical system on the light receiving side such as the objective lens 6a and the imaging lens unit 6 do not need to have a large diameter. Even if there is a light beam, it can be moved and adjusted by a predetermined dimension as irradiation light so that the light beam does not deviate from the outer periphery of the lens to be inspected, so observe the hidden marks and alignment marks especially attached to the periphery of the lens to be inspected. That is, it is possible to surely perform the operation without using a large-diameter optical system, and to improve the operability.
For example, to explain an example of a procedure for observing an alignment mark as a hidden mark of a spectacle lens framed in a spectacle frame in use, first, a transparent glass plate 3a of the mounting table 3 will be described.
Place an eyeglass lens (not shown) above and find the alignment mark near the lens periphery.
At this time, even when the irradiation light from the light source 2 comes off the spectacle frame and is irradiated, as described above, the adjusting knob 4e is manually screwed to move the collimating lens unit 4 to the right in the horizontal direction. Alternatively, the light is slid slightly to the left by a predetermined distance, and by adjusting the parallel light to be transmitted through the spectacle lens, even if the transmitted light is bent by the peripheral portion of the lens to be inspected, the transmitted light is Can be received on the light receiving side, so that the hidden mark and the alignment mark can be confirmed as an image.
After confirming the alignment mark as a hidden mark, in order to determine the optical center position of the spectacle lens, only 17 mm corresponding to a distance of exactly half of 34 mm of the alignment mark distance generally known as a characteristic of lens performance is used. The position moved toward the center of the lens
Since the marking may be made as the optical center of the eyeglass lens to be inspected, it is only necessary to confirm and evaluate the compatibility between the lens to be inspected and the frame in use by using this marking.

The main features to be noted of the lens checker of the present invention will be described below.
In the present invention, it is difficult to easily discriminate and confirm only the observation state of the bright field and the dark field by the conventional device.For example, in the case of similar shaped scratches and dust or dirt, etc., shallow scratches, small scratches and dust etc. As described above, the knife-edge type light-shielding switching means 8 is employed so that even if the conventional apparatus cannot clearly determine the color, a color conversion process using a different hue to the obtained parallax image is performed. Even if it is a slight transmitted light image, it can be displayed as a color change due to a composite image using different hues, so even if it is difficult to distinguish shallow scratches, small scratches, dust, etc. And a parallax image is displayed as a color tone portion (in the case of using a complementary color-related hue, a gray-scaled portion of a complementary color composite color).
Further, by setting the light-shielding switching means 8 in the optical path, a diffraction image is formed by the knife edge effect, and this is obtained as a parallax image. Even for difficult scratches and dust, the determination can be made without fail in color due to the difference in the color tone of the image of the overlapped portion (see FIG. 7).

That is, in the lens checker of the present invention, first, the imaging unit 9 for the mounting table 3 of the lens to be inspected is used.
After performing fine adjustment of focusing with the operation knob 9a, the test lens to be observed is placed on the upper surface of the transparent glass plate 3a of the mounting table 3, and then the initial setting of the focal point on the front surface or the back surface of the lens is performed. The operation is first performed by a vertical movement operation of the mounting table 3 by the adjustment knob 3d.
Next, a description will be given of the characteristic configuration and observation procedure of the lens checker of the present invention.
FIG. 2 is a longitudinal sectional view for explaining an optical system of the lens checker according to the present invention. The transmitted light flux transmitted through a lens (not shown) on the mounting table 3 is converted into an objective lens 6a and imaging lenses 6b and 6c. ,
Immediately before being guided to the imaging means 9 through 6d, the variable stop 7 positioned in the optical path
At the same time as the right-hand knife edge 8a or the left-hand knife edge 8b is alternately advanced into the light path by the light-shielding switching means 8 provided integrally with the light-shielding switch means 8. An operation is performed so as to obtain a parallax image by photographing a transmitted light flux screen.
At this time, in the case of the present invention, the luminous flux transmitted through the lens to be inspected is diffracted by the knife edge effect to form an image by the knife edges 8a and 8b of the light shielding switching means 8, while the luminous flux of half of the blocked visual field is formed. Since it is reliably cut, it does not interfere with the luminous flux of half of the remaining field of view, it is possible to obtain a clear image of the image taken by the imaging means 9, and furthermore, the parallax image obtained as described above is obtained. On the other hand, as shown in FIG. 5, a new parallax image (see FIG. 7) obtained by colorization processing with different hues and a composite image thereof is obtained, and the excellent effect of clearly displaying the difference in color is also exhibited. it can. Note that although FIG. 7 in this embodiment is a monochrome drawing, the portion indicated by the symbol A in the drawing is red, and the portion indicated by the symbol B is a green parallax image portion having a complementary color relationship with red. Since a portion such as a scratch or dust is displayed in a gray scale tone similar to a complementary color as indicated by reference character C, it is difficult to distinguish or observe with a conventional device. Even in this case, the color can be easily distinguished by the difference in the color tone from the surroundings.

With respect to the parallax image obtained by the light-shielding switching means 8 as described above, a method of determining whether there is a flaw or dust or dust present on the surface of the lens to be inspected will be described in detail below with reference to the optical principle diagram of FIG.
Since the imaging means 9 is focused on the surface of the lens to be inspected by the initial setting, the scratches 10
In the case of “a”, as shown in FIG. 6 (A), the image is generally captured as a single-point flaw image. On the other hand, in the case of dust or dust 10c having a similar shape, only the amount of dust or dust 10c rising from the lens surface is considered. As shown in FIG. 6B of the optical principle, the distance between the focal points of the optical axes slightly fluctuates, and the position is double shifted as shown in FIG. The image is displayed as a shadow image of dust or dust having parallax, so that the difference between the two images is clear. Therefore, the latter image can be confirmed as an image of a non-scratched foreign matter, and the combined hue The color tone is also prominent, especially when complementary hues are used, because the complementary color harmony effect makes the gray color tone stand out and projected. Without the use of processing means, There is no need to individually perform a focusing operation for adjusting the lens front and the lens back each time, and the discrimination between the scratch 10a and the dust or dust 10c can be performed human-accurately with high accuracy, inexpensively and easily. It has an effect.

In addition, it is clear that the optical principle and the parallax image of the scratch 10b and the dust or dust 10c on the back surface of the test lens can be determined in the same manner as in FIG. For discrimination, it is only necessary to focus on one of the front and back sides, and the parallax phenomenon accompanying the fluctuation of the distance between the optical axis focal points based on foreign matter such as dust and dust in this state facilitates the discrimination similarly to the above. The detailed description is omitted.

The present invention provides a wide range of observation and inspection of lenses to be inspected such as defects and scratches on eyeglass lenses and other optical lenses, foreign matter and dirt such as dust and dirt, hidden marks and alignment marks, etc. The present invention is useful as a lens checker that can be used for miniaturization and improvement of accuracy in the industrial field of optical technology.

REFERENCE SIGNS LIST 1 lens checker base 2 transmitted light source 2a pinhole type aperture means 3 mounting table for test lens 4 collimating lens unit 4d slide type guide member 4e adjustment knob 6 imaging lens unit 7 iris type variable aperture means 8 Light shielding switching means 8a Right knife edge 8b Left knife edge 9 Image pickup means (CMOS)
11 Image coloring processing means

Claims (2)

At the center of the upper surface of the base provided with the pinhole type aperture means arranged coaxially with the transmitted light source for the test lens, a mount for the test lens is provided, and the mount for the test lens is provided. The collimating lens is arranged concentrically with respect to the optical axis passing therethrough, while the upper end of a column erected on one side of the base has a surface of the lens to be inspected so as to have a coaxial relationship with the light source. Alternatively, an objective lens for forming an image of the back surface, an imaging lens, and a light receiving side optical system including an image pickup unit are arranged to face each other, and an optical light receiving path is provided in an optical path of the image pickup unit constituting the light receiving side optical system. A light-shielding switching means, in which a knife edge is located at the center of the optical axis of the range and which can alternately shield half of the field of view, is provided along the axis perpendicular to the optical axis so as to be able to advance and retreat in the same plane, and the parallax by the imaging means For image data, Color processing means for performing hue image processing having a hue relationship, and synthesizing means for combining the color-processed images, so that the synthesized image formed by these can be displayed on the screen as a new parallax image. A lens checker characterized by the following. The collimator lens is coaxially arranged with respect to the optical axis passing through the lens mounting table provided at the center of the upper surface of the base, and is slidably movable relative to the optical axis in a direction perpendicular to the optical axis. 2. The apparatus according to claim 1, wherein the irradiation position of the transmitted light to the test lens is freely moved to a predetermined position on the test lens by slightly moving the collimating lens. Lens checker.