JP3672562B2 - Lens meter - Google Patents

Description

  The present invention relates to a lens meter that measures optical characteristics such as refractive power in an optical system.

  Conventionally, as described in Japanese Patent Application Laid-Open Nos. 61-280544 and 5-231985, a test lens is placed on a lens base, and a measurement light beam transmitted through the test lens is transmitted. A lens meter is known in which optical characteristics such as spherical power, cylindrical power, and axial angle of a lens to be measured are measured by detection using a photoelectric change type light receiving means.

  In recent years, various progressive lenses have been sold. However, when these progressive focus lenses are processed into a frame, there is a problem that it is difficult to distinguish from the appearance whether the progressive focus lens is a progressive focus lens or a single focus lens. Currently, the lens type is relied solely on the examiner's feeling and the hidden mark attached by the manufacturer, so the progressive focus lens is mistakenly determined as a single focus lens, or the measurement efficiency of the test lens May be reduced.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a lens meter that can easily determine the type of a test lens simply by placing the test lens on a lens base.

  In order to solve such a problem, a feature of the present invention is that at least three points of the measurement light beam projected from the light emitting means and transmitted through the test lens placed on the lens receiver are received. By dividing by a light receiving element having a point and calculating the relative position of each divided light beam, the type of the test lens, that is, the single focus lens or the progressive focus lens is determined, and the test means is used to determine the test target. When it is determined that the lens is a progressive focus lens, the fact that it is a progressive focus lens is displayed.

  Further, when the lens to be measured is a progressive focus lens, the direction of the distance portion or the near portion is calculated from the relative position of each measurement light beam obtained by the calculation means to display that it is a progressive lens. In addition, the direction of the distance portion or the near portion of the lens to be examined is displayed.

  Furthermore, when the alignment means display for the single focus lens and the alignment pattern display for the progressive focus lens are determined by the calculation means to determine that the test lens is a progressive focus lens, Control means for switching to the alignment pattern display for the progressive focus lens may be employed.

  The lens meter according to claim 1 divides the measurement light beam transmitted through the test lens placed on the lens receiver into at least three light beams by a light receiving element, calculates the relative position of each light beam, and calculates the relative position from the relative position. Since it is to determine whether the test lens is a progressive lens, even if the test lens is a lens processed into a frame, it can be easily determined whether it is a single focus lens or a progressive focus lens.

  Further, such a lens meter divides a measurement light beam transmitted through a test lens placed on a lens receiver into at least three light beams by a light receiving element, calculates a relative position of each light beam, and calculates the relative position from the relative position. Whether the test lens is a progressive lens or not, and in the case of a progressive focus lens, the direction of the distance portion or near portion at the position placed on the lens receiver is calculated and displayed. Even if the lens is processed into a frame, it can be easily discriminated whether it is a single focus lens or a progressive focus lens, and it becomes easy to measure the distance portion or the near portion, thereby improving the measurement efficiency.

  The lens meter according to claim 4 divides the measurement light beam transmitted through the lens to be tested placed on the lens receiver into at least three light beams by the light receiving element, calculates the relative position of each light beam, and calculates the relative position from the relative position. It is determined whether or not the test lens is a progressive lens, and has an alignment pattern display for a single focus lens and an alignment pattern display for a progressive lens, and in the case of a progressive focus lens, an alignment pattern display for the progressive focus lens. Therefore, even if the test lens is a lens processed into a frame, it can be easily determined whether it is a single focus lens or a progressive focus lens, and it is easy to measure the distance or near distance In addition, the measurement efficiency can be improved.

  As is clear from the above description, in the lens meter having the structure according to the present invention, it is possible to determine the lens type simply by placing the test lens on the lens receiver. In addition to preventing discrimination, the measurement efficiency of the lens to be tested is increased, and customer serviceability can be improved.

  Hereinafter, in order to clarify the present invention more specifically, embodiments of the present invention will be described in detail with reference to the drawings.

  First, FIG. 1 shows a schematic configuration of a measurement optical system as one embodiment of the present invention. In such a measurement optical system, a measurement light beam 12 is emitted from a light source 10 and is condensed and projected in approximately one direction. A collimating lens 16 as a projection optical system is disposed coaxially with respect to the optical axis 14 of the measuring light beam 12 at the projection destination of the measuring light beam 12 by the light source 10 and transmits through the collimating lens 16. Thus, the measurement light beam 12 is made to be a substantially parallel light beam. Further, a lens 18 to be tested is supported by the lens receiver 5 at the tip of the collimator lens 16 and can be arranged substantially coaxially with the optical axis 14 of the measurement light beam 12. The measurement light beam 12 is made to be a substantially parallel light beam and then transmitted to the lens 18 to be measured. Further, a condensing lens 20 and an imaging lens 22 are arranged on the optical axis of the measurement light beam 12 that has passed through the lens 18 to be measured, and are further spaced apart from each other. A light receiving element 24 is disposed apart from the imaging lens 22 on the optical path of the light beam 12. Then, the measurement light beam 12 that has passed through the test lens 18 is condensed by the condenser lens 20 and then guided to the light receiving element 24 by the imaging lens 22. Further, the light receiving surface of the light receiving element 24 is conjugated with the test lens 18 by the condenser lens 20 and the imaging lens 22, and the measurement light incident on a fixed position of the test lens is detected by the test lens. Regardless of the refractive power of 18 or the like, the light is guided to a certain position on the light receiving surface of the light receiving element 24.

  In short, in the measurement optical system of the present embodiment, the light source 10 and the light receiving element 24 are disposed so as to be opposed to each other on both sides in the optical axis direction with the test lens 18 interposed therebetween, and emitted from the light source 10. The measured light beam 12 is projected onto the test lens 18 through the collimator lens 16, passes through the test lens 18, is guided to the light receiving element through the condenser lens 20 and the imaging lens 22, and is converted into photoelectric conversion elements 26 a to 26 a. It is detected as an electric signal by d (light receiving point).

  In the present embodiment, as shown in FIG. 2, on the light receiving surface of the light receiving element 24, the photoelectric conversion elements (light receiving points) 26a, 26b, 26c, and 26d are positioned at the four corners of the square, respectively. A total of four photoelectric conversion elements are provided. The light receiving element 24 is arranged so that the center of the square formed by the four photoelectric conversion elements 26a to 26d is positioned on the optical axis 14 of the measurement light beam 12, and the light receiving surface is arranged perpendicular to the optical axis 14. The positions of the photoelectric conversion elements 26a, 26b, 26c, and 26d are light detection points on the light receiving surface.

  Further, on the optical path of the measurement light beam 12, a rotary plate 32 having a circular flat plate shape as a rotary chopper located between the condenser lens 20 and the imaging lens 22 is arranged in a direction perpendicular to the optical path. It is installed. The rotary plate 32 is rotationally driven by a drive motor 28 about a rotary shaft 30 that is biased parallel to the optical axis 14 of the measurement light beam 12. Further, the rotating plate 32 has an edge portion that can block the measurement light beam 12 in accordance with the rotational movement around the rotation shaft 30, and the measurement light beam 12 and thus the light receiving element by rotation around the rotation shaft 30. The incident light to 24 is interrupted.

  In particular, in the present embodiment, as shown in FIG. 3, the substantially fan-shaped window portions 34 are 90 ° apart from each other in the circumferential direction at positions intersecting the optical path with respect to the disk-shaped rotating plate 32. It is formed apart. Further, both edge portions 36 and 38 in the circumferential direction of the window portion 34 have mathematically known shapes. In particular, in the present embodiment, any of the edge portions 36 and 38 is light of the measurement light beam 12. The intersection angles α and β with respect to one circumference 40 as the locus of the intersection with the axis 14 are designed to be 45 °. Furthermore, slits 42 a and 42 b for providing a reference position in the circumferential direction of the edge portions 36 and 38 are formed on the outer peripheral portion of the rotating plate 32. In the present embodiment, the rotating plate 32 is disposed on the light receiving element 24 side from the condenser lens 20 at a position separated by the focal length of the condenser lens 20.

  In the lens meter having such a structure, when the test lens is disposed on the optical path, each point corresponding to each of the light receiving points 26a to 26d of the light receiving element 24 that is conjugate with the test lens 18 is provided. The light that has passed through is refracted according to the refractive power characteristics (optical characteristics such as spherical power and cylindrical power) of the lens 18 to be measured, so that the position of the rotating plate 32 on the mounting surface is displaced. It becomes. Therefore, by measuring the displacement amount and the displacement direction of the light transmitted through each point of the test lens 18 on the arrangement surface of the rotating plate 32, the optical characteristics of the test lens 18 are determined from these values. It can be sought. The displacement amount and displacement direction of the transmitted light on the arrangement surface of the rotating plate 32 are determined by using the intermittent position by the edge portions 36 and 38 of the rotating plate 32 as the displacement amount of the rotation angle from the reference position. Since it can be known by detecting each of the 24 photoelectric conversion devices 26a to 26d, it can be obtained by the output signals of the photoelectric conversion devices 26a to 26d and a reference position sensor 44 such as a photoelectric switch using the slits 42a and 42b. The reference position signal of the rotating plate 32 is input to an arithmetic processing unit 46 constituted by a microcomputer or the like, and is subjected to arithmetic processing according to a preset program, whereby the target lens 18 has a spherical power and a cylindrical power. Such optical characteristics can be obtained. Note that a calculation method for obtaining optical characteristics such as spherical power and cylindrical power of the test lens 18 based on the output signals of the photoelectric conversion elements 26a to 26d is described in JP-A-5-231985. , Avoid detailed description here.

  Here, as described above, the position of the test lens 18 and the light receiving element 24 are in a conjugate positional relationship, and the photoelectric conversion elements 26a to 26d of the light receiving element 24 are arranged at the four corners of a square. In the lens 18 to be tested, each point corresponding to each detection point 26a to 26d of the light receiving element 24 which is conjugate forms a square. Then, after passing through the test lens 18, each point is refracted according to the refraction characteristics of the test lens 18, so that the refraction characteristics of the test lens on the arrangement surface of the rotating plate 32. It can be transformed into a square according to

  Here, when the test lens is a single focus lens, the quadrangular shape formed on the arrangement surface of the rotating plate 32 is a parallelogram, and the lengths of opposite sides are equal. If it demonstrates in FIG. 4, if each edge | side of this square will be Lx1, Lx2, Ly1, and Ly2, respectively, Lx1 = Lx2 and Ly1 = 1y2 will be formed.

  However, when the test lens is a progressive focus lens, the quadrangle formed on the arrangement of the rotating plate 32 is deviated from the parallelogram, and the lengths of the opposite sides are not equal. Referring to FIG. 5, if each side of the square is Lx1 ', Lx2', Ly1 ', Ly2', Lx1 '≠ Lx2' and Ly1 '≠ Ly2'.

  That is, on the arrangement of the rotating plate 32, the positions of the points corresponding to the detection points 26a to 26d of the light receiving element 24 are calculated, and the lens 18 to be measured is a single focus lens from the relative positional relationship of the points. It is possible to determine whether the lens is a progressive focus lens.

  In FIG. 5, when Qx = Lx2′−Lx1 ′ and Qy = Ly2′−Ly1 ′, Qx and Qy are generated in the direction of the addition power and addition power of the progressive focus lens. When the test lens is a progressive focus lens, the direction of the addition power can be calculated. If the direction (angle) of the addition is K, tanK = Qx / Qy, and the direction of addition at the position where the lens to be tested is placed, that is, the direction of the distance portion or near portion of the progressive focus lens Can be calculated.

If the measured light beam diameter is La, the progression rate (additional change rate) M at the position where the test lens is placed can be obtained as M = Qx ² + Qy ² / La ² . With the progressive rate M, the relative position in the progressive zone can be detected. Further, by calculating and storing the progressive rate M at a plurality of positions, the properties of the progressive focus lens (for example, the perspective type, the mid-near type, etc.) can be discriminated.

  FIG. 6A shows an alignment pattern for a single focus lens in the present embodiment. 60a in the figure is a target for alignment. If it is determined by the above-described determination method that the lens 18 is a progressive focus lens, a display 60b indicating that it is a progressive focus lens is displayed on the upper left of the alignment pattern. (B)

  In addition to the indication that the lens is a progressive focus lens, FIG. 6C shows the direction of addition at the position where the test lens is placed (in this embodiment, the direction of the near portion) in the upper left part of the pattern. It is supposed to be displayed.

  FIG. 7 is an alignment pattern for a progressive focus lens in the present embodiment. First, the examiner places the distance portion of the progressive focus lens on the lens receiver, aligns the target 70a with the mark 70b in the upper part of the pattern, and then moves the test lens toward the near portion to measure the addition power. To operate. Thus, by using this alignment pattern, the progressive focus lens can be easily measured.

  In the present embodiment, when it is determined by the above-described determination method that the test lens 18 is a progressive focus lens, the alignment pattern for the progressive lens is automatically switched according to the selection of the examiner. It is a thing. The selection of the examiner means that, for example, when it is necessary to switch to the alignment pattern for the progressive focus lens, the switching is automatically performed by holding the test lens for a certain period of time. That is.

It is the figure which showed schematic structure of the measurement optical system as one Embodiment of this invention. It is a front view of the light receiving element employ | adopted with the measurement optical system shown by FIG. It is a front view of the rotating plate employ | adopted with the measurement optical system shown by FIG. It is the figure which showed the square shape (in the case of a single focus lens) after passing through a test lens. It is the figure which showed the square shape (in the case of a progressive focus lens) after a to-be-tested lens transmission. It is the figure which showed the alignment pattern for single focus lenses employ | adopted by this embodiment. It is the figure which showed the alignment pattern for progressive-focus lenses employ | adopted by this embodiment, and the operation method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Light source 12 Measurement light beam 18 Test lens 24 Light receiving element 26 Photoelectric conversion element (light receiving point)
32 Rotating plate

Claims (4)

The measurement light beam projected from the light emitting means and transmitted through the test lens placed on the lens receiver is detected by the photoelectric conversion type light receiving means, and the optical characteristic of the test lens is measured based on the detected value. In the lens meter,
A calculation unit that divides a measurement light beam transmitted through the test lens by a light receiving element having at least three light receiving points, and calculates a relative positional relationship between the divided light beams;
Discriminating means for discriminating whether the type of the test lens is a single focus lens or a progressive focus lens from the relative position of each light beam obtained by the calculation means;
Direction calculating means for calculating the direction of the distance portion or the near portion of the test lens from the relative position of each light beam obtained by the calculating means;
When the determination means determines that the test lens is a progressive focus lens, it displays that the test lens is a progressive focus lens, and based on the calculation result by the direction calculation means, the distance portion of the test lens Alternatively, a lens meter comprising display means for displaying the direction of the near portion.   A light source and a light receiving element are arranged so as to be opposed to each other on both sides in the optical axis direction with the test lens interposed therebetween, and a rotating chopper is provided between the test lens and the light receiving element which are conjugated. The incident light to the light receiving element is interrupted, and the amount of displacement and the direction of displacement of each light beam that has passed through at least three points of the lens to be tested on the surface of the rotating chopper are detected. The lens meter according to claim 1, wherein a relative positional relationship of each light flux in the calculation means is calculated based on a measurement result measured by an element.   The lens meter according to claim 1, wherein the display unit displays the direction of the distance portion or the near portion with an arrow. In the display means,
An alignment pattern for a single focus lens and an alignment pattern for a progressive focus lens are selectively displayed.
If it is determined by the determining means that the test lens is a progressive focus lens, the progressive focus lens can be selected by selecting the examiner by an operation such as holding the test lens for a certain period of time. The lens meter according to claim 1, wherein the alignment pattern is selected and displayed.

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