JP2006106002A - Spectacle lens evaluation method and evaluation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain and evaluate an optimum optical properties of a spectacle lens which corresponds to the state, in which a spectacle lens is worn by the wearers. <P>SOLUTION: Three dimensional shape data of the spectacle lens, containing a measured value of a three-dimensional measurement device which measures the surface shape of the spectacle lens, parameters of the state, in which the spectacle lens is worn, such as the distance from a center of rotation, and material parameters, such as the refractive index of the spectacle lens are input into a computer that calculates the optical properties of the spectacle lens. Optical model of the state, in which the spectacle lenses are worn, is constructed by the computer based on these input data; and by means of this optical model, optical properties at each position on the spectacle lens related to the principal beam, or light flux containing the principal beam in the direction of the line of vision that passes through the center of turning of eyeball are calculated. The calculated results are output to a printer, etc. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an evaluation method and an evaluation apparatus for evaluating the optical performance of a spectacle lens, and in particular, an spectacle lens evaluation method and an evaluation apparatus capable of obtaining optical performance in consideration of a spectacle lens wearing state and an eye gaze direction. About.

  Manufacture and processing of spectacle lenses are performed in accordance with optimized specifications from the designer, but a lens meter is used to evaluate the performance of the spectacle lenses that have been completed. In the measurement with the lens meter, a parallel light beam is projected perpendicularly to the lens surface and the power is measured. A lens meter for measuring the addition power is also known. The measurement with these lens meters is generally a spot measurement. On the other hand, in recent years, apparatuses for measuring optical characteristics of a wide area of a lens have also been proposed (see, for example, JP-A-10-507825, JP-A-8-304228, etc.).

  By the way, when evaluating the optical performance of the spectacle lens, it is necessary to consider the difference from a general optical system (camera or telescope). That is, in the case of a general optical system, for example, with a camera, a wide range of subjects can be photographed on the film surface at once, but when the eye is looking at a wide range, the eyeball rotates around its center of rotation (eyeball To capture the image while moving the line of sight. This is because not all images reflected on the retina of the eye are perceived as a clear image, but only a narrow region of the foveal portion having high resolution is clearly visible.

  On the other hand, the lens meter cannot measure a light beam or a light flux in the visual line direction passing through the center of rotation of the eyeball except on the optical axis of the spectacle lens, and the vertex refractive index in the visual line direction passing through the peripheral part of the spectacle lens. Cannot be measured correctly.

  The present invention has been made based on the above background, and considers the wearing state of the spectacle lens and the line of sight of the eye, and obtains the optimum optical performance of the spectacle lens corresponding to the wearing state of the spectacle wearer. It is an object of the present invention to provide a spectacle lens evaluation method and an evaluation apparatus that can be used.

  In order to achieve the above object, a spectacle lens evaluation method of the present invention includes a spectacle lens including a three-dimensional shape data of a spectacle lens and a distance between an eye-side surface of the spectacle lens and a rotation center of an eyeball as parameters. From the wearing state parameter and the material parameter of the spectacle lens including the refractive index of the spectacle lens as a parameter, the optical performance at each position of the spectacle lens with respect to the principal ray passing through the center of rotation of the eyeball or the light flux including the principal ray is obtained. The eyeglass lens is evaluated.

  That is, in order to perform more optimal optical design of spectacle lenses, various spectacle lenses of single focus and multifocal, especially in progressive multifocal lenses, spectacle lenses for light rays or light fluxes in the line of sight passing through the center of rotation of the eyeball. It is necessary to evaluate the optical performance at each position (not only at the center but also at the periphery). In order to more appropriately evaluate the optical performance of the spectacle lens in the optical system of the spectacle lens and the eyeball, the spectacle lens wearing state, that is, the positional relationship between the spectacle lens and the eyeball, particularly the spectacle lens with respect to the center of rotation of the eyeball It is necessary to consider the positional relationship.

  Further, not only the rotation center distance but also the factors of the wearing state of the spectacle lens, such as decentration, prism prescription, and forward tilt angle of the spectacle lens, vary depending on the individual prescription of the wearer and the spectacle frame to be worn. Therefore, in order to evaluate the optical performance of the spectacle lens more appropriately, it is necessary to construct and carry out an “optical model at the time of spectacle lens wearing” using each factor of the spectacle lens wearing state such as the rotation center distance as a parameter. There is.

  On the other hand, it is conceivable to use a mechanical optical device / mechanism that can freely change the relative positional relationship of the spectacle lens with respect to the center of rotation of the eyeball so that the optical performance in the spectacle lens wearing state can be measured more correctly. However, in such a mechanical optical device, even when the value of each parameter of the spectacle lens wearing state such as the rotation center distance is changed even for the same spectacle lens, it must be measured again each time. When measuring the refractive index distribution of the spectacle lens, it is necessary to move the spectacle lens to many measurement positions for measurement, which requires measurement time.

  The spectacle lens wearing state, that is, spectacles with respect to the center of rotation of the eyeball, from the three-dimensional shape data of the spectacle lens and the spectacle lens wearing state parameter including the distance between the eye-side surface of the spectacle lens and the center of rotation of the eyeball as a parameter The positional relationship between the lenses (optical model when the spectacle lens is worn) is determined, and the optical performance at each position of the spectacle lens with respect to the principal ray in the line-of-sight direction passing through the center of rotation of the eyeball or a light beam including the principal ray is determined.

  That is, one of the features of the present invention is that the distance between the eye-side surface of the spectacle lens and the center of rotation of the eyeball is treated as a parameter without being a fixed factor. This makes it possible to more accurately confirm the substantial optical performance when the spectacle wearer actually wears spectacles. In other words, in the present invention, generally, the distance between the eye side surface of the spectacle lens and the center of rotation of the eyeball varies depending on the spectacle wearer, and if this distance is different, the optical performance of the spectacle lens itself is the same. It focuses on the fact that the actual optical performance when viewed is so different that it cannot be ignored.

By this parameterization of the distance, for example, by using computer simulation or the like, even when the distance is different, the spectacle wearer can accurately determine the substantial optical performance when the spectacles are actually worn. It becomes possible. Furthermore, the present invention similarly parameterizes other factors that change depending on the wearing state other than the distance as wearing state parameters. In addition, parameters that may change depending on the face shape and preferences of the wearer are parameterized. From these parameters and three-dimensional shape data, it is possible to more accurately determine the substantial optical performance of the entire lens when the spectacle wearer actually wears spectacles in consideration of various variable factors. It is what.

  In the spectacle lens evaluation method, the spectacle lens wearing state parameter includes at least the distance between the eye-side surface of the spectacle lens and the center of rotation of the eyeball. In addition to this, eccentricity, prism prescription, spectacle lens It is preferable that the forward tilt angle is included. This is because it is possible to appropriately cope with the wearing state of the spectacle lens such as the prescription of each wearer and the shape of the spectacle frame to be worn.

  The three-dimensional shape data of the spectacle lens is preferably a measurement value obtained by measuring the three-dimensional surface shape of the spectacle lens with a contact-type three-dimensional measuring device using an atomic force probe. This is because a contact-type three-dimensional measuring instrument using an atomic force probe can measure with high accuracy and does not damage the spectacle lens with the probe. However, the measurement of the three-dimensional shape data of the spectacle lens is not limited to a contact-type three-dimensional measuring device using an atomic force probe, and an interferometer or a non-contact three-dimensional measuring device may be used.

  Further, the surface shape of the spectacle lens in the three-dimensional shape data of the spectacle lens is preferably functionalized by a spline function. This is because the spectacle lens surface can be appropriately approximated by the spline function, and there is an advantage that the intersection between the spectacle lens surface and the light beam can be easily obtained when obtaining the optical performance. The optical performance at each position of the spectacle lens is obtained by ray tracing of a chief ray passing through the center of rotation of the eyeball or a light beam including the chief ray.

The spectacle lens evaluation apparatus according to the present invention includes a three-dimensional measuring instrument that measures the surface shape of a spectacle lens, a computer that calculates the optical performance of the spectacle lens from various data for the spectacle lens, and the spectacle lens optics calculated by the computer. An output device for displaying the performance evaluation results,
The computer includes a three-dimensional shape data input unit for inputting data relating to a three-dimensional shape of the spectacle lens including a measurement value of the three-dimensional measuring device, and a distance between the eye-side surface of the spectacle lens and the center of rotation of the eyeball as a parameter A wearing state parameter input unit for inputting a wearing state parameter of the spectacle lens, and a material parameter input unit for inputting a material parameter of the spectacle lens including the refractive index of the spectacle lens as a parameter, and data from these input units And a processing unit for calculating optical performance at each position of the spectacle lens with respect to a principal ray passing through the center of rotation of the eyeball or a light flux including the principal ray.

  In the eyeglass lens evaluation apparatus, the three-dimensional measuring device is preferably a contact-type three-dimensional measuring device using an atomic force probe. Moreover, it is preferable that the processing unit includes a functionalization processing unit that converts the surface shape of the spectacle lens into a function using a spline function based on an input value from the three-dimensional shape data input unit. Further, the processing unit determines the relative positional relationship between the light beam and the spectacle lens when determining the optical performance at each position of the spectacle lens by ray tracing of the principal ray passing through the center of rotation of the eyeball or a light beam including the principal ray. It is preferable to have a coordinate conversion processing unit that performs coordinate conversion to change the value.

  As described above, according to the present invention, the spectacle lens wearing state, that is, the positional relationship of the spectacle lens with respect to the center of rotation of the eyeball (the spectacle lens wearing state), based on the three-dimensional shape data of the spectacle lens and the wearing state parameter of the spectacle lens. And the optical performance at each position of the spectacle lens with respect to the principal ray in the line of sight passing through the center of rotation of the eyeball or a light beam including the principal ray is obtained. For this reason, it is possible to obtain a more appropriate and accurate optical performance of the spectacle lens corresponding to the actual spectacle wearer's wearing state in consideration of the spectacle lens wearing state and the eye gaze direction.

  Moreover, since the evaluation is performed using the three-dimensional shape data of the spectacle lens, the optical performance of the spectacle lens can be calculated at a desired position of the spectacle lens. Furthermore, since the spectacle lens wearing state is determined and calculated based on the spectacle lens wearing state parameters including the rotation center distance of the eyeball, the optical performance is evaluated without re-measurement even if the wearing state changes. be able to.

  In addition, according to the present invention, if the surface shape of one surface of the spectacle lens is obtained, the optical performance can be simulated by giving an arbitrary design value to the surface shape of the other surface, and the optimum prescription can be determined. Obtainable. Also, as a parameter that can be input, a prism value other than a prescription such as prism thinning can be handled as one of parameters that can be input.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram showing an embodiment of an eyeglass lens evaluation apparatus according to the present invention. This evaluation apparatus includes a three-dimensional measuring device 200 that measures the surface shape of a spectacle lens, a computer 100 that calculates the optical performance of the spectacle lens from various data for the spectacle lens, and an evaluation of the optical performance of the spectacle lens calculated by the computer 100. An output device (printer 120, display 130) for displaying the result is provided.

  The computer 100 is a lens surface shape input unit 101 that inputs measurement values of the three-dimensional measuring device 200 as a three-dimensional shape data input unit that inputs data relating to the three-dimensional shape of the spectacle lens including the measurement values of the three-dimensional measuring device 200. And a thickness input unit 102 for inputting the thickness of the geometric center of the spectacle lens measured by a thickness gauge (not shown). Further, as the wearing state parameter input unit for inputting the wearing state parameter of the spectacle lens, a rotation center distance input unit 103 for inputting a rotation center distance between the eye-side surface of the spectacle lens and the rotation center of the eyeball, and the eccentricity of the spectacle lens An eccentric amount input unit 104 that inputs a quantity, a prism prescription input unit 105 that inputs a prism prescription, and a forward tilt input unit 106 that inputs a forward tilt angle of a spectacle lens. Furthermore, as a material parameter input unit for inputting the material parameter of the spectacle lens, a refractive index input unit 107 for inputting the refractive index of the spectacle lens and an Abbe number input unit 108 for inputting the Abbe number of the spectacle lens are provided.

  The computer also obtains the noise cut processing unit 109 for cutting noise included in the measurement value input from the three-dimensional measuring device 200 to the lens surface shape input unit 101, and the lens surface shape data from the lens surface shape input unit 101. It has a spline function fitting processing unit (functionalization processing unit) 110 that functions by a spline function, and a coordinate conversion processing unit 111 that converts a coordinate position such as a lens surface. Further, the computer, based on the data from the input unit and processing unit, a ray tracing calculation processing unit 112 that performs ray tracing of the principal ray passing through the center of rotation of the eyeball in the spectacle lens wearing state and the ray in the vicinity thereof, and this An optical performance calculation processing unit 113 that calculates the optical performance of the spectacle lens from the ray tracing calculation result, and a calculation result display processing unit that performs processing for outputting the optical performance calculation result to the printer 120 and the display 130 are included. .

  Next, measurement of the three-dimensional shape of the spectacle lens will be described. The surface shape of the spectacle lens was measured by the three-dimensional measuring device 200. A description will be given with reference to FIG. 2 showing a flow of pre-processing before the three-dimensional shape measurement and the optical performance calculation. First, the surface shapes of the convex surface (surface on the object side of the lens) and the concave surface (surface on the eye side of the lens) of the spectacle lens are measured. As the 3D measuring instrument, a contact type 3D measuring instrument using an atomic force probe (ultra high precision 3D measuring instrument UA3P manufactured by Matsushita Electric Industrial Co., Ltd.) was used. The measurement data always contains noise, but if the error level is large, it can interfere with proper evaluation, so noise with a large error level (such as dust adhering to the lens surface that is clearly known as noise) Perform pre-processing. This process is performed by the noise cut processing unit 109 of the computer. Further, in the case of a contact-type three-dimensional measuring instrument, each measurement data of a convex surface and a concave surface is a point group of coordinate values of the probe center position when there is no particular processing on the measuring instrument side. To derive a substantial surface of convex and concave surfaces.

  Subsequently, the spline function fitting processing unit 110 converts the measurement data of the convex surface and the concave surface subjected to the noise cut processing and the offset processing into a spline function. In many cases, the measurement data is a point cloud. However, when performing ray tracing or the like, a differential value is required. Therefore, in order to stabilize this calculated value, it is preferable to make the measurement surface a function. A generally used spline function is suitable for the function used at this time. Note that functions such as NURBS may be used as necessary.

  In addition, after measuring the convex surface of the spectacle lens, when measuring the concave surface, the spectacle lens was rotated 180 degrees (the lens surface was inverted) and set to the measurement bed portion. It is in a rotated state. Therefore, by reversing (rotating 180 degrees) either the convex surface data or the concave surface data, the data is brought to the same coordinate system. The coordinate transformation is performed by the coordinate transformation processing unit 111, and generally known affine transformation is used for the coordinate transformation.

  The thickness of the geometric center of the spectacle lens was measured using a thickness gauge (such as S0NY U30). Three-dimensional shape data of the convex and concave surfaces of the spectacle lens can be obtained from the lens thickness data and the lens surface shape converted into the spline function.

  Next, the processing contents for calculating the optical performance of the spectacle lens and displaying the calculation result will be described according to the flow of FIG. First, parameters such as the spectacle lens measurement surface (concave surface, convex surface) spline function and spectacle lens wearing state parameters are input (step S1). An XYZ coordinate system was defined as shown in FIGS. 4 and 5 with a straight line passing through the center of rotation of the eyeball as the X axis. 4 is a side sectional view, and FIG. 5 is a front view.

によって定義される正規化されたｍ階のＢ―スプライン関数である。なお、上記において、ｍは階数、ｈ＋２ｍはｘ方向の節点の本数、ξiはｘ方向の節点定義位置、ｋ＋２ｍはｙ方向の節点の本数、ηiはｙ方向の節点定義位置、ｃijは係数である。 The spline function is converted to a two-dimensional spline function (see Fujimoto et al., “Spline functions and their applications” 5th edition, 1985-2-1 Education Publishing). The fitting method was adopted.
The two-dimensional spline function is

Is a normalized m-th order B-spline function defined by In the above, m is the rank, h + 2m is the number of nodes in the x direction, ξi is the node definition position in the x direction, k + 2m is the number of nodes in the y direction, ηi is the node definition position in the y direction, and cij is a coefficient. .

The convex surface 1a and the concave surface 1b of the spectacle lens 1 are fitted by a spline function of the above type. If the shape function F (Y, Z) of the convex surface 1a and the shape function G (Y, Z) of the concave surface 1b are given, the height (X coordinate position) of the convex surface and concave surface at a certain point (Y1, Z1) is as follows. It can be expressed by F (Y1, Z1), G (Y1, Z1).
F (Y1, Z1) = ΣCij Nmi (Y1) Nmj (Z1)
G (Y1, Z1) = ΣDij Nmi (Y1) Nmj (Z1)
Here, Nmi (Y) Nmj (Z) is a function depending on the node, which is a feature of the spline function. Cij and Dij are coefficients obtained when fitting the shape, and are obtained using the least square method when obtaining the coefficients.

  In the input of each parameter, the thickness value (CT) of the geometric center of the spectacle lens as the shape factor, the rotation center distance (VR) of the eyeball as the factor in the wearing state of the spectacle lens, the value of the eccentricity, the prism prescription When the calculation of the lens refractive index (n) and the chromatic aberration, which are the material factors of the lens, and the Abbe number are input as parameters, respectively. The lens center thickness (CT), the prism value, the forward tilt value, the eccentricity value, and the rotation center distance (VR) of the eyeball are required for the construction of the next optical model. Further, the refractive index (n) and the Abbe number are necessary for ray tracing described later.

  Next, an optical system model when the spectacle lens is worn is constructed (step S2). If the spectacle lens wearing state, that is, the positional relationship of the spectacle lens with respect to the rotation center R of the eyeball (the optical system model when wearing the spectacle lens) is not defined, the optical performance of the spectacle lens when wearing is correctly evaluated. It is not possible.

  This optical model uses parameters of the wearing state such as a prism value, a spectacle lens forward tilt value, an eccentricity value (prescription), and a rotation center distance. Therefore, even if the same spectacle lens is handled, the optical model differs depending on the individual values of each parameter. For example, as shown in FIGS. 6 and 7, the optical model differs depending on the value of the forward tilt angle of the spectacle lens 1. 6 shows an optical model when the forward tilt angle is zero, and FIG. 7 shows an optical model when the forward tilt angle is 7 degrees. 8 to 10 show optical models at the time of wearing when the rotation center distances are different (FIGS. 8, 9, and 10 are the rotation center distances of 20 mm, 27 mm, and 34 mm, respectively).

  Here, the meaning of using the amount of eccentricity (mm) as a parameter is as follows. In other words, the eccentricity means that the eye point at the time of wearing is shifted (eccentric) with respect to the designed eye point. This eccentricity is the case where the eccentricity is intentionally set and the result is not intended. It may be caused by this. The case where the eccentricity occurs unintentionally is a case where the eccentricity is caused by some mistake. In this case, it is possible to numerically confirm the magnitude of the influence of eccentricity that may be erroneously generated by simulating with the amount of eccentricity as a parameter.

  The case where the eccentricity is intentionally set is as follows. That is, for example, in the case of a progressive multifocal lens, a comfortable wearing feeling may be obtained if it is worn eccentrically because of the optical layout and other conditions of the distance portion and the near portion. It is. In addition to this, it is conceivable to intentionally set the eccentricity, but even for such various eccentric prescriptions, simulating with the amount of eccentricity as a parameter can confirm the optical performance in each case. So it has a big meaning. In particular, for example, a general-purpose spectacle lens is designed using a certain average basic wearing condition as a model, so that the lens design may not always suit a specific wearer. In such a case, if simulation is performed using the amount of eccentricity as a parameter, it is also possible to find a wearing condition in which a comfortable wearing feeling can be obtained by selecting the amount of eccentricity.

The prism prescription is used as a parameter in order to cope with various prescriptions, and prism values other than prescription such as prism thinning can be input.
The forward tilt angle of the frame (°) is related to the shape of the frame and how to attach it. In general, an average value (7-8 °) is used for this angle in frame design. However, the actual wearing state may be different from the value. That is the difference in how the individual frame is worn and the shape of the head. In addition, there are frames of various designs in recent years, which causes the forward tilt angle to become diverse and change. Therefore, the parameterization of the forward tilt angle of the frame is effective for simulating various designs of frames and wearing states. The refractive index and the Abbe number depend on the material of the lens, and these parameterizations mean selection of the material, for example, simulation from a low refractive index lens to a high refractive index lens.

  From the input values of parameters such as the concave surface 1b and convex surface 1a of the spectacle lens 1 and the spectacle lens wearing state parameters, the position of the lens convex surface 1a on the XYZ coordinate system, the position of the concave surface 1b, the rotational center position of the eyeball, The position of the reference spherical surface (the spherical surface having the radius of the rotation center distance (VR) about the rotation center R of the eyeball. The power S finally obtained is the reciprocal of the focal length from the reference spherical surface). An optical model is constructed by defining For example, when the center of the convex surface 1a is placed at the origin of coordinates and the concave surface 1b is at a position shifted from that by the center thickness (CT), F (Y, Z) and G (Y, Z) are independent coordinate systems. If defined above, the following expression can be made. That is, the convex surface function F (0,0) coincides with the position of the origin, and the central position of the concave surface 1b in this coordinate system is G (0,0) + CT. If the above expression is used, the position of the rotation center R of the eyeball in this coordinate system is VR + CT.

  Next, the principal ray of the evaluation position for evaluating the optical performance of the spectacle lens is set (step S3). As shown in FIGS. 4 and 5, in the measurement region of the spectacle lens 1, a vector defined by an angle α passing through the rotation center R and the X axis and a rotation angle β using the X axis as the rotation axis is The principal ray is defined as a principal ray, and the principal ray at the evaluation position is set by appropriately setting the values of α and β. In a specific calculation example, the angle α formed with the X axis and the rotation angle β (region of 360 degrees) with the X axis as the rotation axis were both set to a pitch of 5 degrees.

  Next, in order to obtain the optical performance at the diameter at which the luminous flux including the principal ray is incident on the spectacle lens, the incident wavefront of the incident luminous flux including the principal ray incident on the spectacle lens is set as shown in FIGS. (Step S4). In this embodiment, a plane wave enters the incident wavefront. However, the optical performance can be similarly obtained even when the incident wavefront is a spherical wave. In the case of a plane wave, it can be considered that many light rays parallel to the chief ray are incident. Therefore, one chief ray is set so that a light ray group having a φ5 mm region is incident at intervals of 0.5 mm.

Next, ray tracing is performed using Snell's law for each ray of the incident light beam constituting the set incident wavefront (step S5). Each ray of the incident luminous flux can be easily obtained by using Snell's law using a method called reverse ray tracing. The information (numerical values) obtained by ray tracing is as follows:
(1). Passing point P1 (X1, Y1, Z1) on the convex surface of the lens, refracted light vector V1 (XV1, YV1, ZV1) at the passing point P1
(2). Passing point P2 (X2, Y2, Z2) on the concave surface of the lens, refracted light vector V2 (XV2, YV2, ZV2) at the passing point P2.
(3). Passage point P3 (X3, Y3, Z3) on the tangent plane in contact with the reference sphere
(4). Pass point P4 (X4, Y4, Z4) of reference spherical surface
It is. Note that at the passing points P3 and P4 in (3) and (4), the light beam vector does not change and is V2 (XV2, YV2, ZV2). In FIGS. 11 and 12, the passing points and vectors are shown only for the principal ray.

  Next, the optical performance at the set position of the spectacle lens is calculated from the wavefront obtained from the ray tracing (step S6). Optical performance is based on the change between the incident wavefront of the incident light beam incident on the spectacle lens from the object side and the outgoing wavefront when it reaches the reference spherical surface that passes through the spectacle lens and has a radius of the rotation center distance from the rotation center to the lens back surface. Desired.

A Zernike polynomial was used to obtain optical performance from the passing point P3 (X3, Y3, Z3) and the refracted light vector V2 (XV2, YV2, ZV2) obtained by ray tracing. The Zernike polynomial was used to represent the wavefront shape, and the optical performance was determined from the polynomial coefficient. The wavefront W is expressed by the Zernike polynomial as follows.
W ≒ Σa ・ Ze
Here, a is a Zernike coefficient, and Ze is a Zernike polynomial.
What is obtained by ray tracing is not the position of the wavefront, but the refracted light vector means the normal direction of the wavefront,
P ≒ Σa ・ δZe / δY
Q ≒ Σa ・ δZe / δZ
(P and Q are the gradients of the wavefront), the coefficient a is obtained, and the optical performance is obtained from the coefficient a.

  Next, it is determined whether or not the optical performance calculation has been performed at all evaluation positions set (step S7), and the optical performance calculation is repeated by repeating the above steps S3 to S6 until the optical performances at all evaluation positions are obtained. carry out.

  After the completion of the optical performance calculation, display processing of the optical performance calculation result is performed (step S8), and the aberration diagram in the contour line display and the aberration diagram in the bird's eye view display are displayed on the printer and the display (steps S9 and S10). A two-dimensional aberration diagram may also be displayed.

As described above, since the three-dimensional shape of the spectacle lens is measured, the optical performance of the spectacle lens in an arbitrary rotation direction or a convex surface of the lens surface or an arbitrary position on the concave surface in the measured region. Can be calculated. In particular, since the lens surface is a spline function, optical performance can be calculated easily.
Further, as factors in the wearing state of the spectacle lens, the rotation center distance (VR) of the eyeball, the eccentricity, the prism prescription, the forward tilt angle, and the like are defined, and an optical model is constructed by calculation using these values as parameters. Therefore, there is no need to re-measure even if the wearing state changes.

  For example, since the amount of eccentricity (mm) is used as a parameter, the magnitude of the influence of eccentricity that may occur erroneously can be numerically confirmed. In addition, in the case of a progressive multifocal lens, it may be possible to obtain a comfortable wearing feeling when it is decentered actively, but even for such decentration prescription, optical performance is confirmed, so until remeasurement It is possible to find the optimal wearing feeling without any problems.

  In addition, since the prism prescription is used as a parameter, it is possible to deal with various prescriptions, and optical performance can be obtained for prism values other than prescription such as prism thinning. Furthermore, since the frame forward tilt angle is used as a parameter, it is possible to simulate various designs of frames and mounting states. By parameterizing the refractive index and the Abbe number, a simulation from a low refractive index lens to a high refractive index lens can be obtained.

  In the above embodiment, the optical performance at the time of wearing the spectacle lens is calculated based on the three-dimensional measurement of both surfaces (convex surface, concave surface) of the spectacle lens, but even for a semi-finished lens in which only the convex surface is finished, Optical performance can be calculated and evaluated. In other words, in the case of a semi-lens, if the convex surface is measured and three-dimensional shape data is acquired, the concave surface shape can be arbitrarily designed, for example, spherical, aspherical, atoric, free-form surface, and curve setting considering optical aberration By selecting and simulating, etc., it is possible to simulate the optimum concave shape and obtain the optimum prescription. Thus, the present invention can be applied if the three-dimensional measurement data of either the concave surface or the convex surface of both surfaces of the spectacle lens is obtained.

Next, an example will be described in which the optical performance at the center of the rotation point is actually obtained by performing three-dimensional measurement of a progressive multifocal lens. The convex and concave surfaces of the progressive multifocal lens were measured with a three-dimensional measuring instrument. This measurement was performed by scanning at a speed of 4 mm / sec with a convex surface of φ35 mm and a concave surface of φ33 mm at a pitch of 1 mm. In addition, noise cut and offset processing were calculated for the measured values. In the spline function, fitting was applied to the 6th-floor spline function with 29 nodes in the X and Y directions in the area of the convex surface ± 35mm. Also, fitting was applied to the 6th-floor spline function with 24 nodes in the X and Y directions in the area of concave surface ± 33mm. In the calculation of optical performance, the following values were used as input parameters.
Center thickness of lens 7.20mm
Refractive index 1.501
Abbe number 58
Eccentricity 0.0
Prism prescription value 0.00
Forward tilt value 0.00
Rotation center distance 27mm

  The data calculated under these conditions are shown in FIGS. FIG. 13 is an S frequency (average frequency) distribution diagram, and FIG. 14 is a C frequency (cylindrical frequency) distribution diagram. In FIG. 13 and FIG. 14, the concentric circles written with dotted lines represent the rotation angle α and are shown at a pitch of 5 degrees. The pitch of the contour lines is 0.5D (dioptre). 15 is a bird's eye view corresponding to the S frequency distribution of FIG. 13, and FIG. 16 is a bird's eye view corresponding to the C frequency distribution of FIG. FIG. 17 shows the numerical data (β = 90 degrees) of S frequency (diopter (Dptr)), C frequency (diopter (Dptr)), and AX (astigmatic axis, degree (Deg)) obtained at this time. , Rotation angle α = value in the range of −45 degrees to +45 degrees).

It is a schematic block diagram which shows one Embodiment of the spectacles lens evaluation apparatus which concerns on this invention. It is a flowchart which shows the pre-processing before the three-dimensional shape measurement and optical performance calculation of an eyeglass lens. It is a flowchart which shows the processing content which calculates the optical performance of a spectacles lens, and displays the calculation result. It is a figure which shows the coordinate system of the optical model at the time of spectacle lens wearing at the time of calculating | requiring the optical performance of a spectacle lens. It is a figure which shows the coordinate system of the optical model at the time of spectacle lens wearing at the time of calculating | requiring the optical performance of a spectacle lens. It is a figure which shows each optical model at the time of spectacles lens wearing when the value of the forward inclination angle of a spectacles lens differs. It is a figure which shows each optical model at the time of spectacles lens wearing when the value of the forward inclination angle of a spectacles lens differs. It is a figure which shows each optical model at the time of spectacles wear when rotation center distance is 20 mm. It is a figure which shows each optical model at the time of spectacles wearing in case rotation center distance is 27 mm. It is a figure which shows each optical model at the time of spectacles wear in case a rotation center distance is 34 mm. It is a figure for demonstrating the ray tracing and optical performance with respect to the light beam containing the chief ray which passes along the rotation center. It is the elements on larger scale of FIG. It is S frequency (average power) distribution map of a progressive multifocal lens. It is C power (cylinder power) distribution map of a progressive multifocal lens. It is a bird's-eye view corresponding to S frequency distribution of FIG. It is a bird's-eye view corresponding to C frequency distribution of FIG. It is a table | surface which shows the numerical data which calculated the optical performance of a progressive multifocal lens.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Eyeglass lens 1a Convex surface 1b Concave surface 2 Eyeball 100 Computer 101 Lens surface shape input part 102 Thickness input part 103 Rotation center distance input part 104 Eccentricity amount input part 105 Prism input part 106 Forward tilt angle input part 107 Refractive index input part 108 Abbe number Input unit 109 Noise cut processing unit 110 Spline function input unit 111 Coordinate transformation processing unit 112 Ray tracing calculation processing unit 113 Optical performance calculation processing unit 114 Calculation result display processing unit 120 Printer 130 Display R Rotation center VR Rotation center distance CT Center thickness

Claims (7)

A three-dimensional shape factor of the spectacle lens, a wearing state factor of the spectacle lens including the distance between the eye-side surface of the spectacle lens and the center of rotation of the eyeball as parameters, and a material factor of the spectacle lens including the refractive index of the spectacle lens Each parameter of the eyeglasses is parameterized so that it can be set variably, a predetermined value is selected, and the optical aberration at each position of the spectacle lens with respect to the chief ray passing through the center of rotation of the eyeball or a light beam including the chief ray is obtained. A method for evaluating a spectacle lens, comprising evaluating a lens. The spectacle lens wearing state factor includes, in addition to the distance between the eye-side surface of the spectacle lens and the center of rotation of the eyeball, eccentricity, prism prescription, and forward tilt angle of the spectacle lens. Item 2. A method for evaluating an eyeglass lens according to Item 1. The surface shape of the spectacle lens in the three-dimensional shape factor of the spectacle lens is:
3. The spectacle lens evaluation method according to claim 1, wherein the spectacle lens is functionalized by a spline function. 4. The optical aberration at each position of the spectacle lens is obtained by ray tracing of a principal ray passing through the center of rotation of the eyeball or a light beam including the principal ray.
The evaluation method of the spectacle lens in any one of. 5. A spectacle lens design method comprising a step of evaluating a spectacle lens using the spectacle lens evaluation method according to claim 1 in the spectacle lens design process. A three-dimensional measuring instrument that measures the surface shape of the spectacle lens, a computer that calculates the optical aberration of the spectacle lens from various data for the spectacle lens, and an output device that displays the evaluation result of the optical aberration of the spectacle lens calculated by the computer The computer includes:
A three-dimensional shape data input unit for inputting data relating to a three-dimensional shape of the spectacle lens including the measurement value of the three-dimensional measuring device, and a spectacle lens including a distance between the eye-side surface of the spectacle lens and the center of rotation of the eyeball as a parameter A wearing state parameter input unit for inputting the wearing state parameter, and a material parameter input unit for inputting a material parameter of the spectacle lens including a refractive index of the spectacle lens as a parameter, based on data from these input units, A spectacle lens evaluation apparatus comprising: a processing unit that calculates an optical aberration at each position of the spectacle lens with respect to a principal ray passing through the center of rotation of the eyeball or a light flux including the principal ray. The spectacles according to claim 6, wherein the processing unit includes a functionalization processing unit that functionalizes a surface shape of the spectacle lens by a spline function based on an input value from the three-dimensional shape data input unit. Lens evaluation device.

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