JP4781705B2 - Lens meter - Google Patents

Description

  The present invention relates to a lens meter for measuring optical characteristics of a spectacle lens.

In a lens meter that measures optical characteristics of a spectacle lens, a test lens placed on a predetermined mounting table is a single focus lens or a progressive power lens (hereinafter referred to as a progressive lens) in order to eliminate erroneous determination of the test lens. ) Is automatically determined, and when it is determined to be a progressive lens, there is proposed a display that displays a pattern indicating a progressive zone, a distance portion, and a measurement site on a display portion (Patent Document 1). In this case, the optical properties (prism value, spherical power, cylindrical power, axial angle) of four different measurement sites are calculated, and the optical properties of each region are compared, so that the optical properties of each measurement site are converted into prism values. On the other hand, the type of lens to be examined is determined based on whether or not there is almost no change.
JP-A-7-19998

  However, as in Patent Document 1, when the type of the test lens is determined based on whether or not the optical characteristics of each measurement site are substantially unchanged with respect to the prism value, there is a scratch in the measurement area of the test lens. If there is dirt or dirt, misidentification may occur in automatic discrimination. In other words, when a single-focus lens with a flaw in the measurement area is identified, the optical characteristics of each measurement site are not substantially changed with respect to the prism value due to the flaw, and it is erroneously determined as a progressive lens. There is a risk that.

  In view of the above problems, an object of the present invention is to provide a lens meter capable of accurately performing automatic determination as to whether a test lens is a single focus lens or a progressive addition lens.

  In order to solve the above problems, the present invention is characterized by having the following configuration.

(1) Place the test lens framed with the upper or lower end of the spectacle frame in contact with the lens rest on the nose piece, measure the optical characteristics of the test lens, and In a lens meter that displays an alignment screen on the display to guide the movement of the lens,
Holds an index plate on which a large number of indexes of a predetermined pattern having a certain regularity are formed in the opening of the nosepiece, and projects the measurement light beam to pass through the lens to be tested , the opening of the nosepiece and the index plate A measurement optical system that receives the measured light beam as an index pattern image composed of a plurality of index images on a light receiving element and obtains optical characteristics of the test lens;
Image position detection means for quantitatively obtaining an interval between the index images arranged in the vertical direction with respect to the test lens based on an output signal from the light receiving element on which the index pattern image is projected;
Depending on whether or not the interval between the index images arranged in the vertical direction quantitatively determined by the image position detecting means tends to increase or decrease with respect to the regularity in the vertical direction of the index formed on the index plate . Determining means for determining whether the test lens is a progressive power lens or a single focus lens, wherein the interval between the index images continuously increases or decreases with respect to the regularity in the vertical direction of the index Even when the relationship between the index images detected by the image position detection means has an overall increasing or decreasing tendency with respect to the regularity of the index in the vertical direction, Determining means for determining that the lens is a progressive addition lens;
When the determination means determines that the test lens is a single focus lens, the display screen is displayed as a single focus lens measurement mode alignment screen, and the determination means is a progressive power lens. When it is determined that there is a display / measurement mode control means for switching the display screen to an alignment screen having a lens mark for switching to the progressive power lens measurement mode and switching to the progressive power lens measurement mode;
It is characterized by providing.

  According to the present invention, it can be automatically determined with high accuracy whether the lens to be examined is a single focus lens or a progressive power lens.

  Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic external view of a lens meter according to the present embodiment.

  Reference numeral 1 denotes a lens meter main body. Reference numeral 2 denotes a display composed of an LCD or the like, which displays information necessary for measurement such as measurement results and alignment targets. 2a is an alignment screen on the display 2. Reference numeral 3 denotes an input switch unit, and by pressing a switch corresponding to the switch display displayed on the display 2, a necessary input instruction such as switching of the measurement mode can be performed. Reference numeral 4 denotes a nosepiece as a mounting member on which the test lens LE is mounted. Reference numeral 5 denotes a lens presser, and the lens LE placed on the nosepiece 4 can be stably held by lowering the lens presser.

  Reference numeral 6 denotes a lens pad that is movable in the front-rear direction. In the measurement of the lens LE with a spectacle frame, the lower ends of the left and right frames (in this specification, the upper and lower of the spectacle frame and the lens means the upper and lower in a state where the spectacles are worn. The lens to be tested LE can be stably placed on the nosepiece 4. In this embodiment, the direction of the test lens LE placed on the nosepiece 4 can be specified by bringing the lower end of the spectacle frame into contact with the lens pad 6, but the present invention is not limited to this. The direction of the test lens may be specified by bringing the upper end of the spectacle frame into contact with the lens pad 6.

  Reference numeral 7 denotes a marking mechanism. Reference numeral 8 denotes a READ switch for reading the optical characteristic data of the lens LE. By pressing the switch 8, the measured value is held on the display 2 and stored in the memory inside the apparatus.

  FIG. 2 is a schematic configuration diagram of the optical system and the control system. Reference numeral 10 denotes a measurement optical system, and L1 denotes its measurement optical axis. The measurement optical system 10 includes a measurement light source 11, a collimating lens 12, a mirror 13, and a grid plate 14 which is a measurement index plate on which a predetermined index pattern having a certain regularity (for example, see FIG. 3) is formed. A two-dimensional light receiving sensor 15 is provided. The grid plate 14 is held by the holding member 16 of the main body 1, and the opening 4 a of the nose piece 4 is positioned on the grid plate 14. In addition, the opening of the nosepiece opening 4a in the present embodiment is a circle having a diameter of 8 mm. As another configuration of the index pattern formed on the measurement index plate, for example, a regularly arranged lattice pattern can be considered.

  FIG. 3 is a diagram illustrating an example of an index pattern formed on the grid plate 14. The outer diameter of the grid plate 14 is formed to be slightly larger than the inner diameter of the opening 4 a of the nosepiece 4. On the rear surface of the grid plate 14 (surface on the light receiving sensor 15 side), a measurement index 20 composed of a number of circular holes is formed. The measurement index 20 in the present embodiment includes a center hole 21 formed at the center position through which the measurement optical axis L1 passes, and a large number of small holes 22 arranged around the center hole 21 in a lattice shape. The center hole 21 corresponds to a reference index for specifying the correspondence relationship of the other holes 21, that is, each dot corresponding to the “0D reference” in the state without the lens LE when the lens LE is placed. Used as a reference index for identifying an image. The small hole 22 outside the light receiving surface of the light receiving sensor 15 is provided so as to be received by the light receiving sensor 15 when the prism power is generated by being arranged in the measurement optical path of the lens LE. It is.

  The light beam from the measurement light source 11 is collimated by the collimating lens 12, reflected by the mirror 13, and projected onto the lens LE placed on the nosepiece 4. Of the light transmitted through the lens LE, the light beam that has passed through the holes 21 and 22 of the grid plate 14 is received by the light receiving sensor 15 as an index pattern image (see FIG. 4).

  An output signal from the light receiving sensor 15 is input to the control unit 40. The control unit 40 is connected to a memory 42 for storing coordinates of the “0D reference” dot image (index image) detected in a state without the lens LE when the apparatus is turned on, measurement information, and the like. When the lens LE is not placed, the control unit 40 uses the coordinate position of the dot image of the small hole 22 incident on the light receiving sensor 15 as a reference, and each dot image when the lens LE having a predetermined refractive power is placed. The optical characteristics (spherical power S, columnar power C, astigmatism axis angle A, prism amount Δ) of the lens LE are calculated from the position change.

  For example, when a spherical lens having a plus power is placed, an index pattern image (dot pattern image) in which the distance between the dot images is smaller than that on the case where there is no lens LE to be detected is received on the light receiving sensor 15. Projected on. On the other hand, when a spherical lens having a minus power is placed, an index pattern image in which the distance between the dot images is increased is projected onto the light receiving sensor 15 as compared with the case where the test lens LE is not provided. In addition, when an astigmatic lens having a predetermined astigmatism axis is placed, an index pattern image distorted in an elliptic shape according to the astigmatism axis and the astigmatism power of the lens is projected. The prism amount Δ is obtained from the parallel movement amount of the center dot image of the lens LE or the dot image in the vicinity thereof. A lens having a spherical power, a columnar power, and a prism may be considered as a composite of these (see Japanese Patent Laid-Open No. 50-145249).

  Here, the optical characteristics of the lens LE to be measured can be obtained as a set of four adjacent (at least three) dot images. Therefore, according to the configuration of the measurement index of this apparatus, information on a plurality of measurement positions can be obtained at once in the nosepiece opening 4a, and an optical characteristic distribution in the nosepiece opening 4a can be obtained. For this reason, in the progressive lens, whether the current measurement position is in the distance portion, similarly, whether the current measurement position is in the near portion, or whether it is in the progressive zone, etc. However, it can be detected efficiently.

  Note that the measurement optical system that can measure the refractive power distribution in a predetermined region such as the inside of the nosepiece opening 4a without moving the lens to be measured is not limited to the configuration shown in FIG. For example, the grid plate 14 may be arranged closer to the light source 12 than the lens LE, or the light source 12 may be arranged in a grid shape. For measurement of the refractive power distribution, it is preferable to form measurement positions in the vertical direction and the horizontal direction at least about the measurement optical axis.

  In addition, the control unit 40 performs display control of the display 2. The current measurement position in the following description is used to mean the center of the measurement optical axis L1 among a plurality of measurement positions. For example, the fact that the current measurement position is in the near portion indicates that the near portion of the test lens LE is located on the measurement optical axis L1.

  The operation of the lens meter having the above configuration will be described focusing on the automatic determination mode described above. Here, when the test lens LE is placed on the nosepiece 4 by the examiner, the control unit 40 places the test lens LE based on the change of the index pattern image projected onto the light receiving sensor 15. Detect that. In the present embodiment, it is assumed that the optical characteristics of the test lens LE are obtained in a state where the lower end of the spectacle frame is in contact with the lens pad 6.

  When the placement of the test lens LE is detected, automatic determination of whether the test lens is a progressive lens or a single focus lens is started. In the present embodiment, the control unit 40 detects the image position of each index image (dot image) based on the output signal from the light receiving sensor 15 on which the index pattern image is projected, and moves up and down with respect to the test lens. The distance between the index images arranged in a line in the direction is obtained by calculation processing.

  For example, when the test lens LE is a single focus lens, the index pattern image projected onto the light receiving sensor 15 is projected onto the light receiving sensor 15 with the distance between the index images being equidistant (for example, (See the dotted line in FIG. 4). On the other hand, when the test lens LE placed on the nosepiece 4 is a progressive lens, the index pattern image projected onto the light receiving sensor 15 is projected at different positions in the vertical direction due to changes in the addition of the progressive zone. The distances between the index images thus projected are projected onto the light receiving sensor 15 in a state where the equidistant relationship is broken (see, for example, the dotted line in FIG. 5A).

  Therefore, the control unit 40 uses the difference in the positional relationship between the index images when the single focus lens is mounted and the progressive lens as described above to determine whether the mounted lens is a single focus lens or a progressive lens. Judge whether or not. In other words, the control unit 40 calculates the distance between the index images arranged in a line in the vertical direction with respect to the test lens LE based on the index pattern image projected on the light receiving sensor 15, and calculates the distance between the index images from the calculation result. Are compared, and if they are increasing or decreasing within a predetermined range, it is determined that the lens is a progressive lens. On the other hand, if there is no tendency to increase or decrease within a predetermined range, it is determined that the lens is a single focus lens. In the present embodiment, the index row at the center of the grid plate 14 shown in FIG. 3 is used as the vertical index image arrangement (index row) used for the determination.

  More specifically, for example, as shown in FIG. 5, when the distance between the index images (dot images) arranged in the index row used for determining the lens type is K1 to K10, as shown in FIG. If there is a continuous increase (decrease) in the distance between the index images of K1 <K2 <K3 <... K8 <K9 <K10, it is assumed that the vicinity of the progressive zone of the progressive lens is detected. It is determined that the lens LE is a progressive lens (other index images are omitted). Further, as shown in FIG. 6, each index used for determination can be obtained even if the distance between the index images does not continuously increase (decrease) due to scratches, dust, dust, etc. on the lens LE in the middle. If the distance relationship between images has an increasing tendency (decreasing tendency), the control unit 40 automatically determines this as a progressive lens. Conversely, if such an increasing tendency (decreasing tendency) cannot be obtained, the control unit 40 determines that the lens is a single focus lens.

  In this way, when automatic determination is performed for a single focus lens with scratches in the measurement area, the distance between the index images is the same distance due to the disappearance or missing of the index images. The possibility of being determined as a progressive lens is reduced. Therefore, misidentification at the time of automatic determination can be prevented.

  When detecting the continuous increase as described above, at least four index images arranged in a line in the vertical direction with respect to the test lens are sufficient, but the distance between the index images of the test lens LE is suddenly increased. In order to exclude the change, it is preferable to obtain distance information between a large number of areas and a large number of index images. For example, it may be detected whether or not the distance between the index images tends to increase in a range of 4 mm or more corresponding to 1/2 of the nosepiece opening 4a.

  In addition, although the method for preventing misidentification at the time of automatic determination is described above, the distance between the index images tends to increase or decrease in the vertical direction and is not continuously increased or decreased. In this case, the control unit 40 may display a sign indicating that there is a high probability of the progressive lens having scratches or dirt, and that the lens 2 to be examined has scratches or dirt on the display 2. In addition, when the distance between the index images is not equal, and the distance between the index images cannot increase or decrease in the vertical direction, the control unit 40 Is likely to be a single focus lens with scratches or dirt, and a sign indicating that the lens LE is scratched or dirty may be displayed on the display 2.

  Further, according to the present embodiment, the test placed on the nosepiece 4 based on the increasing direction of the interval between the index images obtained quantitatively (may be the increasing direction of the addition power). It is possible to determine whether the lens is correctly installed in the vertical direction. That is, if the interval between the index images at the lens upper position is smaller than the interval between the index images at the lens lower position, it is determined that the lens LE is installed upside down (for example, as shown in FIG. 5A). The opposite of the indicator pattern). When it is determined that the lens LE is installed upside down, a warning to that effect is displayed on the display 2.

  Furthermore, in the present embodiment, the distance between the index images is used for determining the type of the test lens, but the present invention is not limited to this, and the interval between the index images is quantitatively obtained and determined. What is necessary is just to use for a material. For example, the vertical coordinate of each index image arranged in a line in the vertical direction with respect to the test lens can be used.

  In addition, when the lens to be examined has a column surface power, the index images aligned in the vertical direction with respect to the lens to be examined may be slightly tilted due to the influence of the astigmatism power. Is included in the category of wording that "

  Furthermore, when the index image of the index string used for the determination is greatly affected by scratches or dust on the lens to be examined, the index image of the adjacent index string can be used, or the left and right It is also possible to obtain an interval (distance) between the index images in the vertical direction by obtaining an average of the positions of the index images in the direction.

  As described above, in order to prevent misidentification at the time of automatic determination, the control unit 40 automatically determines the test lens LE depending on whether or not the interval between the index images tends to increase or decrease in the vertical direction. However, such a determination method itself can be performed based on the optical characteristic distribution in the nosepiece opening 4a. That is, as a result of calculating the optical characteristic distribution in the nosepiece opening 4a, the SE value (equivalent spherical value) or S value increasing region in the region measured as shown in FIGS. When the distance is equal to or longer than a predetermined distance (for example, 4 mm) and there is a continuous increase during that time, the lens is determined to be a progressive lens. FIG. 8 is a diagram showing the distribution of the optical characteristics of the single focus lens when there are scratches or dirt in the measurement region. In this case, although the SE value itself changes in the measurement region, it cannot be said that it continuously increases. That is, by using the above-described determination method, it is possible to prevent a single focus lens having optical characteristics as shown in FIG.

  FIG. 9 is a distribution when measuring the optical characteristics when measuring the vicinity of the progressive zone of the progressive lens, and showing the distribution of the optical characteristics when there are scratches or dirt in the measurement region. When the lens is scratched in this way, the SE value at each measurement position does not necessarily increase continuously, but the change in SE value at each adjacent measurement position is within a predetermined range, As a result, when SE changes continuously, this is regarded as a progressive zone, and the lens LE is determined as a progressive lens. In this way, it is possible to obtain substantially the same effect as the above-described method. In this case, any configuration may be used as long as optical characteristics can be obtained at three measurement positions in different vertical directions.

  Even in this case, if the optical characteristic distribution obtained as described above tends to increase or decrease with respect to the vertical direction of the lens to be measured and is not continuously increasing or decreasing, control is performed. The unit 40 may be a progressive lens with scratches and dirt, and may display a sign indicating that the test lens LE has scratches or dirt on the display 2. In addition, when the optical characteristic distribution obtained as described above has a change in the vertical direction of the lens to be examined and an increase or decrease in the vertical direction cannot be obtained, the control unit 40 may be a single focus lens having scratches or dirt, and a sign indicating that the lens LE is scratched or dirty may be displayed on the display 2.

  Next, when it is determined by automatic determination that the test lens is a progressive lens or a single focus lens, the subsequent measurement operation will be briefly described below.

  When it is determined that the lens is a progressive lens, a display indicating that the lens is a progressive lens is made to the examiner, and the mode is automatically switched to the progressive lens measurement mode (see FIGS. 10 and 11). In FIGS. 10 and 11, reference numeral 100 denotes a lens mark having a progressive band graphic that makes an image of a progressive lens, and reference numeral 101 denotes a cross mark indicating the current measurement position. FIG. 10 is a display screen displayed when alignment to the distance portion is performed, and reference numeral 102 denotes a distance portion mark that makes the image of the distance portion appear. In this case, as shown in FIGS. 10A and 10B, the test lens LE is moved so that the distance portion mark 102 is directed to the intersection of the cross marks 101. Then, as shown in FIG. 10C, when the measurement position reaches the distance portion, the large cross mark 103 is displayed instead of the distance portion mark 102. FIG. 11 is a display screen that is displayed when alignment of the near portion is performed after measuring the optical characteristics of the distance portion, and 120 is a near portion mark that makes the near portion image. In this case, as shown in FIGS. 11A to 11C, the test lens LE is moved so that the near portion mark 120 is directed to the intersection of the cross marks 101. Then, as shown in FIG. 11D, when the measurement position reaches the near portion, a large cross mark 125 is displayed instead of the near portion mark 120.

  When it is determined that the lens is a single focus lens, the screen display is not changed, and the POINT measurement for obtaining a single measurement value from the four dots corresponding to the central position of the nosepiece 4 is switched. At this time, the target 202 is displayed at a position indicating the current measurement position (see FIG. 12). In this case, the examiner moves the test lens LE so that the target 202 is directed to the intersection of the cross marks 201 while looking at the display 2.

  As described above, according to the present embodiment, it is possible to automatically determine whether the test lens is a single focus lens or a progressive lens simply by placing the test lens on the nosepiece 4, and it is troublesome for the examiner to determine. Can be reduced. Further, by controlling the display screen of the display 4 together with the switching of the measurement mode as described above, it is possible to smoothly shift to the measurement of the optical characteristics of the test lens LE.

  When it is determined that the lens is a progressive lens, a message as to whether or not to switch to the display screen is displayed instead of automatically switching to the progressive lens measurement mode, and a display such as FIG. It is good also as a structure which switches to.

1 is a schematic external view of a lens meter according to the present embodiment. It is a schematic block diagram of the optical system and control system of the lens meter which concerns on this embodiment. It is a figure which shows an example of the parameter | index pattern formed in the grid board. It is a figure which shows the parameter | index pattern image projected on the light receiving sensor. 6 is a graph showing an example of an index pattern image projected on a light receiving sensor and an interval between index images when the lens to be tested LE is a progressive lens. FIG. 6 is a graph showing an example of an index pattern image projected on a light receiving sensor and an interval between each index image when the test lens LE is a progressive lens with a scratch or the like. It is a figure which shows the optical characteristic distribution in the case of determining with a progressive lens. It is a figure which shows distribution of the optical characteristic of a single focus lens when there exists a crack and dirt in a measurement area | region. It is a distribution when measuring the optical characteristics when measuring the vicinity of the progressive zone of the progressive lens, and is a diagram showing the distribution of the optical characteristics when there are scratches or dirt in the measurement region. It is a figure which shows the display screen at the time of performing alignment to a distance part in a progressive lens measurement mode. It is a figure which shows the display screen at the time of performing alignment to a near part in a progressive lens measurement mode. It is a figure which shows the display screen of single focus lens measurement mode.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lens meter 2 Display 4 Nosepiece 6 Lens contact 10 Measurement optical system 14 Grit board 15 Light receiving sensor 40 Control part LE Test lens

Claims (1)

The test lens framed with the upper or lower end of the spectacle frame in contact with the lens rest is placed on the nose piece, the optical characteristics of the test lens are measured, and the test lens on the nose pin is measured . In a lens meter that displays an alignment screen to guide movement on the display ,
Holds an index plate on which a large number of indexes of a predetermined pattern having a certain regularity are formed in the opening of the nosepiece, and projects the measurement light beam to pass through the lens to be tested , the opening of the nosepiece and the index plate A measurement optical system that receives the measured light beam as an index pattern image composed of a plurality of index images on a light receiving element and obtains optical characteristics of the test lens;
Image position detection means for quantitatively obtaining an interval between the index images arranged in the vertical direction with respect to the test lens based on an output signal from the light receiving element on which the index pattern image is projected;
Depending on whether or not the interval between the index images arranged in the vertical direction quantitatively determined by the image position detecting means tends to increase or decrease with respect to the regularity in the vertical direction of the index formed on the index plate . Determining means for determining whether the test lens is a progressive power lens or a single focus lens, wherein the interval between the index images continuously increases or decreases with respect to the regularity in the vertical direction of the index Even when the relationship between the index images detected by the image position detection means has an overall increasing or decreasing tendency with respect to the regularity of the index in the vertical direction, Determining means for determining that the lens is a progressive addition lens;
When the determination means determines that the test lens is a single focus lens, the display screen is displayed as a single focus lens measurement mode alignment screen, and the determination means is a progressive power lens. When it is determined that there is a display / measurement mode control means for switching the display screen to an alignment screen having a lens mark for switching to the progressive power lens measurement mode and switching to the progressive power lens measurement mode;
A lens meter comprising: