JP7060239B2 - Lens checker - Google Patents

Description

The present invention relates to a so-called lens checker used for visual inspection and observation of scratches, stains, dust, hidden marks, etc. on the surface of a lens to be inspected such as a lens for spectacles, a contact lens, and other optical lenses. The present invention relates to a device suitable for inspection and observation of veins inside the lens to be inspected and poor surface polishing.

For spectacle lenses and contact lenses in use, people use a lens checker configured to visually identify foreign matter such as scratches, dirt, dust and dirt on the front and back of the lens from the image on the light receiving screen or image pickup screen. In the case of visual observation or inspection, the following various problems existed.
That is, in the case of deep scratches on the surface of the lens to be inspected, or in the case of large scratches or foreign substances such as large dust and dirt, the refraction ratio and reflection ratio of the transmitted light transmitted through the scratches and dust are large. While it is relatively easy to grasp in terms of optics, in the case of veins due to abnormal material density distribution inside or uneven polishing corresponding to shallow scratches on the surface, transmitted light that is refracted or reflected light that is reflected Since it is difficult to optically capture the detected light such as, it becomes impossible to visually discriminate or observe the image based on the detected slight light, and at the same time, the numerical value of the image data based on the detected light is small, so that it is mechanical. It is becoming more difficult from the viewpoint that it is necessary to improve the analysis accuracy of the detector for discrimination, and the demand and improvement measures for the discrimination device for such veins, shallow scratches, uneven polishing, etc. like the latter are eagerly desired. The current situation is that it has been done.
In addition, the image pickup device, screen, etc. on the light receiving side have a general configuration in which the outer diameter dimension is increased to increase the light receiving range with respect to the optical system such as the collimating lens on the light source side, and particularly in the optical system. The tendency to increase the diameter is due to the fact that the part of the foreign matter existing on the test lens is not specified, and in the case of hidden characters and marks, it is generally engraved near the peripheral edge of the test lens. Therefore, it is unavoidable to increase the diameter of the optical system so as to cover the entire test lens.

Further, in the case of a conventional image pickup type lens checker in which an image pickup 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 test lens, and the test lens is illuminated with bright field or dark field. Although it is illuminated to make scratches stand out, the diameter of the optical system on the light receiving side that receives scattered light is inevitably increased, and scratches, stains, and hidden marks observed in the dark or bright field are inevitable. In order to determine whether foreign matter or foreign matter is present on the front surface or the back surface of the lens, it is necessary to perform a focus adjustment operation (focusing) on the front surface image and the back surface image of the lens each time to re-image. It was accompanied by the annoyance.
On the other hand, the discrimination between the normal part of the test lens and the scratch or foreign matter is grasped as the light intensity distribution or the brightness distribution by using the captured image data without human visual observation of the captured image, or the discrimination is mechanically performed. In order to make a determination, a brightness sensor and an arithmetic processing means for mechanically processing data are required, which complicates the optical equipment and increases the cost of the arithmetic processing means, resulting in high cost. It was inconvenient.

As described above, it is a lens checker for human visual observation, and is an illumination optical system 2 including a light emitting diode 5 for observing the lens L to be inspected, a pinhole plate 6, and a collimator lens 7.
As a precedent example configured to visually observe an image or an image output screen on the screen 4 by providing an image pickup means such as a large-diameter projection screen 4 arranged opposite to each other in a co-axis relationship.
For example, the following Patent Document 1 also provides a lighting unit 120 integrated with a diffuser plate 20 for observing a lens 5 to be co-axis-adjustable with respect to a CCD camera 30 or the like arranged opposite to each other.
As a precedent example, for example, a scratch or a foreign substance is mechanically determined by measuring the luminance distribution related to the light intensity of the transmitted light from the image data transmitted through the lens 5 and quantifying the luminance or the like and performing a comparative calculation. The following Patent Document 2 further observes the pulse of the subject 12 in order to further observe the subject 12.
A polarizing plate 4 is arranged in the optical path on the laser light source 1 side, and a knife edge 6 is arranged as a set in the optical path at the focal position of the image pickup lens 5 on the light receiving side, and these polarizing plates 4 and the knife edge 6 are synchronized. For example, the following Patent Documents 3 are known as precedent examples for observing the pulse using an image obtained by controlling the rotation of the lens. It was not possible to solve the problem of discrimination accuracy related to the reason and uneven polishing of the surface.
Japanese Unexamined Patent Publication No. 10-132707 Japanese Unexamined Patent Publication No. 9-269276 Japanese Unexamined Patent Publication No. 7-31153

The first problem to be solved in the present invention is at least on the light receiving side in the optical path of the optical system including the test lens in order to enable visual discrimination of the pulse based on the abnormality of the material density distribution of the test lens itself. By appropriately incorporating a polarizing element (or wave plate) for controlling the polarization of the transmitted light transmitted through the test lens and providing an operation freely, the polarization component of the transmitted light transmitted through the test lens in the XY direction can be appropriately limited. However, only the abnormal transmitted light beam that is double-reflected in a direction different from the polarization component in the XY direction in the pulse part inside the test lens is received by the imaging means, and this is a clear pulse image based on the pulse. Therefore, the pulse can be made into a simple structure without providing a synchronous operation and control mechanism between the polarizing plate on the light source side and the knife edge on the light receiving side as in the above-mentioned prior document 3. The purpose is to provide an excellent lens checker that can reliably and inexpensively perform human discrimination and observation of optics.

Then, as an incidental problem in the present invention, the light beam is limited by the pinhole type narrowing means that limits the irradiation light from the light source on the light source side as in the above-mentioned prior document 1, and the specific optical axis center light beam is collimated. The lens is irradiated with the test lens as a parallel light beam to obtain the knife edge effect provided in the optical path after the test lens is transmitted, and the image receiving device on the light receiving side makes the image by the transmitted light of the test lens stand out. There is no big difference in obtaining the so-called Schlieren effect, but the feature is that the collimated lens unit of the irradiation light is relatively slid by a predetermined amount in the horizontal direction orthogonal to the optical axis on the light source side. By freely providing it, the irradiation position of the transmitted light to the test lens can be changed and adjusted as appropriate, and the transmitted light beam bent in the test lens can be adjusted so that it can receive light, and the optical system such as a collimating lens is large. By suppressing the diameter reduction, it is possible to reduce the diameter of the optical system on the light receiving side as well as to reduce the diameter.
As in Cited Document 1, the diameter of the light-receiving side optical system such as the light-receiving side large-diameter screen (or CCD camera) can be reduced, and the lens checker as a whole can be miniaturized. The purpose is to provide an observation type lens checker.
Furthermore, as an incidental problem in the present invention, instead of the brightness sensor required for mechanical determination and the expensive arithmetic processing means for digitizing image data as in Cited Document 2, the light amount can be easily adjusted in the imaging optical system. By adding a means and a knife-edge type light-shielding switching mechanism, not only a parallax image can be obtained, but also the effect of the Schlieren optical system described above can be combined with the scattered light image of transmitted light due to uneven polishing on the surface of the lens to be inspected. It is an object of the present invention to provide a lens checker that can improve sharpness at low cost and can discriminate images at low cost.

A mounting table for the test lens is provided at the center of the upper surface of a base provided with a pinhole type aperture means coaxially arranged with a light source for transmitted light for the test lens, and the test lens mounting table is provided. While the collimating lens is arranged almost coaxially with the penetrating optical axis, the surface of the lens under test is placed on the upper end of the column planted on one side of the base so as to have a co-axis relationship with the light source. Alternatively, an objective lens for capturing an image on the back surface, an imaging lens, and a light receiving side optical system composed of an imaging means are arranged to face each other, and at least the light receiving side optical system composed of the imaging lens and the imaging means is inspected. A decoder for polarizing one of the XY components of the transmitted light from the lens is appropriately provided in the optical path as an intervening operation, and the XY components of the transmitted light are appropriately restricted. It is characterized in that it receives only the refracted light beam and is configured to be capable of imaging.

Further, in the optical path of the image pickup means constituting the light receiving side optical system in the present invention, a light shielding switching means capable of alternately blocking half of the field of view by locating a knife edge at the center of the optical axis of the optical light receiving range. , A polarizing element or a wave plate for limiting the XY component of the transmitted light is provided integrally with the light-shielding switching means, and each element is provided so as to be freely advancing and retreating in the same plane along the orthogonal axis with respect to the optical axis. It is characterized in that the procedure of the switching operation of is uniquely performed.
In addition, a collimated lens arranged substantially coaxially with the optical axis penetrating the test lens mounting table provided in the center of the upper surface of the base so as to form the light source side optical system in the present invention is provided with respect to the optical axis. It is characterized by being arranged so that the slide movement can be adjusted relatively in the horizontal direction orthogonal to each other, and by slightly moving the collimating lens, the irradiation position of the transmitted light to the test lens can be moved and adjusted. Is to be.

In the lens checker of the present invention, a mounting table for the test lens is provided in the center of the upper surface of a base provided with a pinhole type aperture means coaxially arranged with a light source for transmitted light for the test lens. While the collimating lens is placed with respect to the optical axis penetrating the lens mounting table, the upper end of the column planted on one side of the base is tested so as to have a co-axis relationship with the light source. An objective lens for capturing an image of the front surface or the back surface of the lens, an imaging lens, and a light receiving side optical system composed of an imaging means are arranged to face each other, and the light receiving side optical system composed of the imaging lens and the imaging means is arranged. A polarizing element for polarizing at least one of the XY components of the transmitted light from the test lens is appropriately provided in the optical path so that the XY components of the transmitted light are appropriately restricted. Since only the double-reflected light beam is received and can be imaged, only the double-reflected light beam transmitted through the pulse in the subject lens body is made to stand out because the transmitted light component from the normal part is blocked. Since it is possible to obtain a clear image of the lens portion due to this, it is possible to exert an excellent function of easily visually discriminating the lens, which has been difficult to visually discriminate by humans. be.
The feature of the present invention is that a knife edge is located at the center of the optical axis of the optical light receiving range in the optical path of the image pickup means constituting the light receiving side optical system, and half of the field of view (in the horizontal plane). A light-shielding switching means capable of alternately blocking the left-right direction or half of the front-back direction) is provided so as to be able to freely advance and retreat in the same plane along the axis orthogonal to the optical axis, and the light-shielding switching means is integrated with the light-shielding switching means. A polarizing element or a wave plate for limiting the XY component of light is provided, and the procedure of each switching operation is uniquely performed. In the lens meter device of the present invention, when switching to the optical path, the operation procedure is always performed in order, that is, there is no risk of setting the knife edge and the transducer in the optical path at the same time, so that the operation is erroneous. It is surely prevented from doing so, and the inspection and observation work with excellent safety and accuracy are guaranteed. Even if, for example, a drive actuator for automatically operating these is provided, it is only possible. Since it requires only one drive system, it is economical in terms of configuration, and can exhibit practical effects having excellent operability and economic efficiency as a device.

As a matter of course, scratches and dust on the surface of the lens under test have more remarkable scattering of transmitted light than the above-mentioned pulse, so that visual discrimination based on the obtained image can be easily performed as before. Of course, regarding uneven polishing of the surface of the test lens, even when the transmitted light of the test lens is received as scattered light due to uneven polishing, the transmitted light near the center of the optical axis, which has a particularly strong amount of light, is received. However, it is limited by the knife edge, making it easier to see the scattered light around it, and it is possible to capture a clear image with clear contrast as polishing unevenness. Since it is not necessary to use a brightness sensor, an expensive arithmetic processing means, or the like, it is possible to exert an excellent practical effect of being able to discriminate or observe inexpensively and reliably.

Further, in the lens checker of the present invention, collimated lenses arranged substantially coaxially with the optical axis penetrating the test lens mounting table provided in the center of the upper surface of the base are relative to each other in the horizontal direction orthogonal to the optical axis. By arranging the collimating lens so that the slide movement can be adjusted, and by slightly moving the collimating lens horizontally, the irradiation position of the transmitted light to the test lens can be moved and adjusted to the test lens. Not only is it suitable for observing hidden marks that are often provided near the peripheral edge of the subject lens, but also the irradiation light from the light source refracted by the pinhole type aperture means is emitted from the subject lens. Even if the collimating lens may come off, by slightly moving the collimating lens horizontally in the left-right (or front-back) direction, it is possible to irradiate the subject lens as appropriate without the irradiation light coming off the subject lens. Since the transmitted light transmitted through the lens under test can be reliably captured by the optical system on the light receiving side, the diameter of these optical devices can be reduced at least within the range in which horizontal movement operation is possible, and the device as a whole can be viewed. However, it can also exert an excellent effect that can be miniaturized at low cost.

Further, since the image pickup type lens checker of the present invention is provided with a knife edge in the same plane as a light blocking switching means, the other half of the optical field of view, for example, the other half in the left-right direction with respect to one (right half) image. Since the transmitted light of the (left half) can be shielded from each other so that they do not interfere with each other, each half of the image can be captured as a clear image, and the accuracy of human reading and discrimination of the observed image is greatly improved. It also has the excellent effect of being able to improve.

A perspective view showing an embodiment of the overall configuration of the lens checker of the present invention. A vertical sectional view for explaining a main body portion in an embodiment of the lens checker of the present invention. Enlarged cross-sectional view of the base portion seen from the direction of the arrow AA in FIG. Optical diagram for explanation in the lens checker of the present invention An optical explanatory view showing the principle of pulse imaging in the lens checker of the present invention. An enlarged plan view showing an embodiment in which a polarizing element and a light-shielding switching means in the lens checker of the present invention are integrated. An explanatory photograph that captures the pulse with 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 entire lens checker of the present invention, the central portion of the upper surface of the base 1 is shown.
Corresponding to the irradiation light from the built-in transmitted light light source 2, for example, a diaphragm plate 2a as a diaphragm means in which a pinhole 2b of about 50 microns is perforated in the center is provided close to and coaxially with the light source 2. , An irradiation light beam with a small amount of ambient light near the central axis from the pinhole 2b drilled in the center is passed through with a predetermined refractive angle with respect to the optical axis, and is passed to the lens Le on the lens mounting table 3 to be described later. It is configured to be irradiated as parallel light by the collimating lens unit 4 (see FIGS. 2 and 3) corresponding to the above.
On the light source side in one embodiment of the present invention, as described in detail in FIGS. 2 and 3, an operation dial 1 for adjusting the amount of light of the light source 2 is placed on the base 1 of the lens checker device.
In the case of the illustrated embodiment, the transparent glass plate 3a for mounting the test lens is assembled on the top of, for example, a black cylindrical plastic cylinder 3b while maintaining the coaxial relationship with the light source 2 while providing a. The attached test lens mounting table 3 is arranged in a cantilever support state by the support arm member 3c, and the mounting table 3 still manually screw-operates the adjustment knob 3d of the cantilever support portion, for example. Therefore, the optical system on the light source side is configured so that it can be freely moved and operated at least in the vertical direction on the same axis along the optical axis, and the focal position of the image receiving means 9 on the light receiving side, which will be described later, can be appropriately changed and adjusted. ..
The transparent glass plate 3a and the plastic cylinder 3b for mounting the test lens are not limited to a circular or cylindrical shape, and for example, a quadrangular one is used to form the test lens mounting table 3. Needless to say, it is also good.

Further, the feature on the light source side of the present invention is that, for example, for light collection with a relatively small diameter while maintaining a constant gap substantially coaxially with the cylinder 3b inside the cylinder 3b of the lens mounting table 3 to be inspected. A collimating lens unit 4 for irradiation light composed of lens groups 4a, 4b, and 4c is combined, and the collimating lens unit 4 is provided by a slide-type guide member 4d horizontally provided on a base 1. While being supported in the air inside the tubular body 3b while still in the cantilever support state, by manually screwing the adjustment knob 4e attached to the support portion, for example, when viewed from the front of the device with respect to the base 1. In the horizontal plane orthogonal to the optical axis penetrating the lens mounting table 3 above, the optical axis is relative to the optical axis according to the size allowed by the fitting gap with respect to the inner surface of the tubular body 3b. Since the lens is configured to be slightly movable while maintaining the parallel relationship, the irradiation light passing through the collimating lens unit 4 can be irradiated to the lens Le to be inspected by this relative movement operation (optical diagram of FIG. 4). (See), and since it is possible to receive the transmitted light beam bent by the test lens Le on the light receiving side, a hidden mark that is generally provided near the peripheral edge of the test lens is often provided. Not only is it configured to be convenient for observing, for example, the lens Le to be inspected receives transmitted light beam when it is incident on an inclined surface or a surface having a small radius of curvature such as a high curve lens or a contact lens. It is an advantageous mechanism in terms of the above, and it is possible to reduce the size of the entire device by these operation mechanisms.
In the illustrated embodiment, an example is shown in which a point light source 2, a pinhole 2b, and a collimating lens unit 4 are used for the optical system on the light source side, and a parallel light beam advantageous for obtaining sharpness of an image on the image pickup side is used. However, the light source 2 and the collimating lens unit 4 in these optical systems
The configuration is not limited to the embodiment of the present invention, for example, a stable LED white light source is adopted, or both light sources are provided so that the light source can be switched and used according to the work.
Changes may be implemented as necessary.

Further, as a basic feature of the present invention, in the illustrated embodiment, as an example, the first polarizing element is appropriately brought close to or overlapped with the transparent glass plate 3a in the test lens mounting table 3 of the light source side optical system. (Or the first wavelength plate) 20a is arranged coaxially, and any component of the XY components in the irradiation light, for example, the X component is blocked as shown in FIG. 5, and the selection control is performed only for the remaining Y component. The lens Le to be examined is irradiated as the polarized light beam, and the light emission of the specific (Y component) transmitted light is combined with the light shielding control for the transmitted light beam transmitted through the normal portion of the lens Le to be examined. Only the transmitted light beam transmitted through the portion of the pulse 21a having an abnormal density distribution in the lens Le and double-reflected is used as the detection light on the light receiving side.
On the other hand, as shown in FIG. 2, the upper end of the support column 5 planted on one side of the upper surface of the base 1 is transparent as the light receiving side optical system of the mounting base 3 under the coaxial relationship with the transmitted light light source 2. The objective lens 6a and the imaging lens unit 6b, 6 are placed in an overhang state with the imaging means 9 (for example, CMOS or the like) for capturing an image by the transmitted light beam transmitted through the test lens Le so as to face the glass plate 3a.
It is supported together with the imaging lens unit 6 composed of c and 6d, and the image data obtained by the imaging means 9 is enlarged and displayed on a display screen (not shown) of a personal computer or a tablet, and this screen is displayed humanly. It is designed to be observed or inspected, and these configurations are not basically different from the configurations of the conventional imaging type lens meter, but as a characteristic configuration in the case of the present invention, the first polarizing element 20a on the light source side is used. A second polarizing element (or a second wave plate) 20b is appropriately arranged in the optical path of the light receiving side optical system so as to be able to move forward and backward in the optical path. The X component is cut by the polarizing element 20a of the above, and the transmitted light of only the Y component is further polarized by the second polarizing element 20b to create a dark field state. As described above, when the test lens Le has a pulse 21a that causes double refraction, the double refracted transmitted light is the first and second polarizing elements 2.
The light is received through 0a and 20b, and this is configured so that it can be imaged by the imaging means 9 as a white pulse image 21b. And the inspection can be performed reliably.
Note that 9a in the figure indicates an operation knob for finely adjusting the focus of the image pickup means 9.

In addition, in the present invention, as one of further incidental features, as shown in FIGS. 2 to 4, on the light source side, the irradiation light from the irradiation light light source 2 receives the pinhole effect of the aperture plate 2a. It is refracted as limiting light and is further irradiated from the back surface of the mounting table 3 via the collimating lens unit 4 arranged coaxially with the aperture plate 2a, whereas on the light receiving side, it faces the mounting table 3. In a basic optical system in which an objective lens 6a guides an image forming lens unit 6 as a lens surface image or a back image by parallel light transmitted through a lens Le to be imaged, and the image is formed on the image pickup means 9, the image pickup means. In the optical path in front of 9, for example, a variable aperture means 7 in the form of an iris aperture, such as continuously narrowing and changing the optical path area in which the amount of light can be adjusted, and knife edges 8a and 8b at the center of the optical axis of the optical light receiving range. The light-shielding switching means 8 is configured so that half of the field of view (for example, the left-right direction in the horizontal plane or the half in the front-back direction) can be alternately blocked in the same plane (see FIG. 6). It is equipped with a light-shielding switching means 8 that can be freely moved forward and backward along an axis orthogonal to the optical axis, and is configured so that the image pickup means 9 can appropriately capture a disparity image as needed.
That is, as shown in FIG. 6, the shading switching means 8 of the present invention is arranged so as to block, for example, the right semicircular portion and the left semicircular portion in the optical field by the knife edges 8a and 8b, respectively. Along an axis orthogonal to the optical axis of the imaging lens unit 6, a knife edge 8a or 8b of any of the light-shielding switching means 8 is selectively provided in the optical path so that the knife edge can be freely entered and exited. The transmitted light beam whose central light beam is blocked by either 8a or 8b is arranged so as not to interfere with the semicircular transmitted light beam on the unobstructed side and affect the diffracted image.
Each of them is configured to obtain a clear parallax image, and it is an expensive arithmetic processing means for visually discriminating and observing polishing unevenness on the surface as well as general scratches and dust or dust on the surface of the lens to be inspected. It is designed so that it can be easily and inexpensively performed by humans without using it.

Incidentally, in the embodiment of FIG. 6, the second polarizing element 20b is integrally parallel to the light-shielding switching means 8 in the light-receiving side optical system by the imaging lens unit 6 and the imaging means 9 in order to ensure operability. However, if it is possible to separately provide an appropriate malfunction preventing means such as an operation procedure, it is not necessary to integrally provide the polarizing element 20b with the light-shielding switching means 8, and it is appropriately optical. If they can be arranged coaxially in the optical path, they can be provided separately, but it is advantageous in terms of configuration because the drive system can be unified if they are configured integrally. It is advantageous because operability and malfunction prevention effect can be realized with a simple configuration.
Further, if the layout is not restricted in the optical path on the light receiving side in front of the image pickup means 9, the first and second polarizing elements 20a provided on the light source side are abolished.
And 20b may be combined as a proximity polymerization structure and arranged at least in the optical path on the light receiving side.
Further, these splitters 20a and 20b can be operated to limit the transmitted luminous flux by using a wave plate capable of blocking and controlling the wavelength component of the transmitted light of the test lens as an alternative. It is possible for a person skilled in the art to appropriately select and adopt which configuration is adopted without departing from the gist of the present invention.

Further, in the embodiment of the present invention, the light-shielding switching means 8 provided with the knife edges 8a and 8b is an iris whose optical path area can be continuously changed and adjusted by operating, for example, a diaphragm knob 7a or a dial (not shown). A diaphragm-type variable diaphragm means 7 is integrally provided, and the variable diaphragm means 7 is selected in the optical path along an axis orthogonal to the optical axis of the imaging lens unit 6, similarly to the light-shielding switching means 8. It is provided so that the entry / exit operation can be freely performed, whereby the brightness of the image can be freely adjusted by the aperture adjustment effect on the image pickup means 9, and it is advantageous to perform human discrimination observation of scratches on the surface of the lens to be inspected. It was configured.
The form of the variable diaphragm means 7, the knife edges 8a, 8b, the polarizing element 20b, and the like illustrated in FIG. 6 is not limited to this illustrated embodiment, and for example, they are individually combined without being integrally combined. It may be provided and configured to be operated individually, but if it is configured integrally, not only is it certain that the switching operation procedure is performed without fail, but also the drive system for operation is ensured. Even when an actuator is required, it is economically advantageous and preferable because it requires only a single system, and other changes such as configuring manual operation to an automatic operation method have the basic purpose and effect of the present invention. Any configuration may be adopted as long as it does not deviate.
Further, it goes without saying that the type of the variable aperture means 7 is not limited to the embodiment.

Hereinafter, the operation procedure of the lens checker of the present invention, the observation procedure, and the like will be described with reference to the attached drawings.
First, in the lens checker of the present invention, when inspecting or observing the lens under test, the inspection or observation is started.
The test lens 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, and the light intensity of the irradiation light source 2 is adjusted by the operation dial 1a. However, an image of the transmitted light from the test lens Le is taken by the image pickup means 9, and this image pickup data is transmitted to a personal computer or the like and displayed on the display screen, and internal defects of the test lens, scratches on the surface, and hidden marks, or We humanly observe and inspect scratches, dust, dirt, etc., but in the case of surface scratches such as the former and hidden characters and marks, the operation procedure and observation procedure are almost the same as the conventional ones. Instead, the brightness and sharpness of the image are adjusted and observed by the operation knob or dial operation (whether manual or automatic) of the variable aperture means 7.

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 inspected. It means that the collimated light can be irradiated without coming off. More specifically, even if 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 are not configured to have large diameters, that is, irradiation of the light beam by the collimating lens unit 4 Since the irradiation position of the irradiation light can be slightly moved so that the position does not deviate from the lens Le to be inspected, especially for hidden characters and marks often attached to the peripheral edge of the lens Le to be inspected. However, it is possible to observe reliably without using a large-diameter optical system.
For example, to explain an example of a procedure for observing a hidden mark of a spectacle lens framed in a spectacle frame in use, first, a spectacle lens (not shown) is placed on a transparent glass plate 3a of a mounting table 3. Place it and find hidden letters and marks near the periphery of the lens.
At this time, even if the irradiation light from the light source 2 is emitted off the spectacle frame, the collimated lens unit 4 is moved to the right in the horizontal direction by manually screwing the adjustment knob 4e as described above. Alternatively, by slightly sliding it to the left and adjusting the parallel light to be emitted so as to pass through the spectacle lens, the transmitted light can be received on the light receiving side, for example, in the case of a high curve lens. Even so, hidden characters and marks can be confirmed as images.
Furthermore, in order to obtain the optical center position after confirming the hidden characters and marks, the lens is only 17 mm, which corresponds to exactly half the distance of 34 mm between the hidden characters and alignment marks, which is generally known as a characteristic of lens performance. The position moved toward the center may be marked as the optical center position of the spectacle lens to be inspected, and this marking may be used to confirm and evaluate the compatibility between the lens to be in use and the frame.

And in particular, regarding the remarkable characteristic pulse discrimination procedure of the lens checker of the present invention.
The following will be described with reference to FIG.
As described above, in order to discriminate and observe the pulse inside the test lens, which has been difficult to easily discriminate and confirm only by the observation state of the bright field and the dark field by the conventional device, the test lens mounting table 3
In the first polarizing element 20a appropriately arranged on the back surface of the transparent glass plate 3a, the polarization of one of the XY components (for example, the X component) is adjusted with respect to the irradiation light from the light source 2 to be covered. Only the remaining Y component of the irradiation light is transmitted from the back surface of the inspection lens Le.
If the pulse 21a is present in the lens Le to be inspected, the pulse 21a is present.
Due to the abnormal strain of a and the difference in density distribution, the transmitted light transmitted through this pulse portion is transmitted as a polarized light beam subjected to double refraction, and at the same time, the Y component of the transmitted light beam transmitted through the normal portion is the first. Since it is polarized by the second polarizing element 20b, the light receiving screen becomes the screen 22 in the dark field state in which the XY component of the transmitted light is limited, whereas the transmitted light subjected to double refraction by the pulse 21a is the second. Since it does not receive the polarization of the polarizing element 20b, it appears as a pulse image 21b with clear light and darkness on the light receiving screen, and the image pickup means 9 clearly captures and captures this pulse (see FIG. 7).
This makes it possible to reliably and reliably discriminate and determine the pulse, which was conventionally considered difficult to visually discriminate.
That is, as is clear from the optical explanatory view of FIG. 5 based on the above optical principle, in the pulse photograph shown in FIG. 7 obtained by the lens checker of the present invention, the XY component of the transmitted light with respect to the lens Le to be inspected is present. The central part (arrow A part) different from the restricted surrounding part represents the part of the pulse image 21b that has undergone double refraction due to the pulse 21a, and what is because the transmitted light is originally limited. The pulse image A (21b) can be visually confirmed on the light receiving screen, which should not be visible, so please refer to it. The arrow B portion in FIG. 7 is an ink portion of the marker pen.

In the above embodiment, there is an example in which the X component of the irradiation light is limited by the first polarizing element 20a on the light source side and the Y component of the transmitted light is limited by the second polarizing element 20b on the light receiving side. As described above, the limitation of these XY components may be performed by either the first polarizing element 20a or the second polarizing element 20b, but at least on the light receiving side, the main transmitted light transmitted through the test lens is used. It is necessary to control the cutoff of the wavelength component and to be able to receive the transmitted light beam birefringent for the pulse 21a.

Incidentally, to explain the procedure for discriminating or observing, for example, scratches and dust and dirt having similar shapes, shallow scratches, and uneven polishing of the surface of the lens to be inspected using the so-called Schlieren optical system on the light receiving side. In this case, since the knife edge type light blocking switching means 8 is incorporated in the optical path on the light receiving side, the cause is scratches on the lens surface, uneven polishing, etc. in a state where the amount of light near the center of the optical axis due to the knife edge effect is suppressed. It is possible to appropriately obtain a clear diffraction image by receiving the scattered light.
That is, in the lens checker of the present invention, first, the image pickup means 9 for the mounting table 3 of the test lens
After fine-tuning the focus of the lens with the operation knob 9a, place the lens Le to be observed on the upper surface of the transparent glass plate 3a of the mounting table 3, and then set the initial focus on the front or back surface of the lens. First, the adjustment knob 3d of the mounting table 3 is used to move up and down.
Next, the variable diaphragm located in the optical path shown in FIG. 2 immediately before the transmitted luminous flux transmitted through the test lens on the mounting table 3 is guided to the image pickup means 9 via the objective lens 6a and the imaging unit 6b. At the same time as moving the 7 out of the optical path, the right side knife edge 8a or the left side knife edge 8b of the light shielding switching means 8 provided integrally with the 7 is alternately advanced into the optical path, so that the luminous flux for each half is reached. Take a picture of the screen and operate it so that a parallax image can be obtained as appropriate.
However, if the parallax image for each half is not required, an operation may be performed so as to obtain a diffraction image using one of the knife edges.
At this time, in the case of the present invention, the light flux of half of the field of view transmitted through the test lens is diffracted by the knife edge effect 8a and 8b in the shading switching means 8 to form an image, while forming an image.
Since the luminous flux near the center of the optical axis in half of the blocked field of view is reliably cut, the image captured by the imaging means 9 is obtained as a clear image without interfering with the luminous flux of half of the remaining field of view. You can do it.

It should be noted that the present invention is not limited to the examples shown in the illustration and described in the text, and alternative elements of the constituent elements are adopted as long as they do not deviate from the gist of the present invention, or are changed to the constituent elements within the technically equivalent range. Since it is possible to freely configure and implement such as adopting and implementing, detailed explanation is omitted.

The present invention is a device for observing and inspecting the surface of a lens to be inspected, and has a wide range of defects such as spectacle lenses and other optical lenses such as veins, uneven polishing and scratches, foreign matter such as dust and dirt, stains, hidden letters and marks. It is useful as a lens checker that can be used for observation and inspection of the lens to be inspected, and at the same time, it can be used for miniaturization and improvement of accuracy in the industrial field of optical technology.

1 Base of lens checker 2 Light source for transmitted light 2a Pinhole type diaphragm plate 3 Placement stand for test lens 4 Collimated lens unit 4e Adjustable knob 6 Imaging lens unit 7 Iris-type variable diaphragm means 8 Shading switching means 8a Right side Knife edge 8b Left side Knife edge 9 Imaging means (CMOS)
20a First polarizing element 20b Second polarizing element 21a Pulse 21b Pulse image

Claims (3)

A mounting table for the test lens is provided at the center of the upper surface of a base provided with a pinhole type aperture means coaxially arranged with a light source for transmitted light for the test lens, and the test lens mounting table is provided. While the collimating lens is arranged almost coaxially with the penetrating optical axis, the surface of the lens to be inspected is located on the upper end of the column planted on one side of the base so as to have an axial relationship with the light source. Alternatively, an objective lens for capturing an image on the back surface, an imaging lens, and a light receiving side optical system composed of an imaging means are arranged to face each other, and at least the light receiving side optical system consisting of the imaging lens and the imaging means is inspected. A decoder for polarizing one of the XY components of the transmitted light from the lens is appropriately provided in the optical path as an intervening operation, and the XY components of the transmitted light are appropriately restricted. A lens checker characterized in that it receives only the refractive light and is configured to be capable of imaging. In the optical path of the image pickup means constituting the light receiving side optical system, a light shielding switching means having a knife edge located at the center of the optical axis of the optical light receiving range and capable of alternately blocking half of the field of view is provided orthogonal to the optical axis. In addition to being provided so that it can be freely moved forward and backward in the same plane along the axis, a splitter or wave plate for limiting the XY component of the transmitted light is provided integrally with the light-shielding switching means, and the procedure for switching each element is as follows. The lens checker according to claim 1, wherein the lens checker is configured to be uniquely performed. A collimating lens arranged substantially coaxially with the optical axis penetrating the test lens mounting table provided in the center of the upper surface of the base so as to form the light source side optical system is relative to the direction orthogonal to the optical axis. The above-mentioned claim 1 is characterized in that the collimating lens is arranged so as to be adjustable in slide movement, and the irradiation position of transmitted light to the test lens can be adjusted in movement by slightly moving the collimating lens. The lens checker according to item 2.

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