Lens measurement method and lens measurement device

Abstract

The surface shape of the first surface (8a) of the lens (8) is measured by the shape measuring unit (2) to determine the center position of the first surface (8a) of the lens (8), and the lens (8) is positioned on the transmitted wave surface measuring unit (3) on the basis of the center position of the first surface (8a) of the lens (8) and the previously determined and stored relative position of the shape measuring unit (2) and the transmitted wave surface measuring unit (3). The transmitted wave surface of the lens (8) is measured by a transmitted wave surface measurement unit (3), and the optical characteristics of the lens (8) are obtained from the transmitted wave surface.

Description

Technical Field

[0001] The present disclosure relates to a lens measuring method and a lens measuring device for measuring optical characteristics of a lens. Background Art

[0002] Patent Document 1 discloses a lens measurement method for measuring the shape error of the front and back surfaces of a lens. This lens measurement method calculates the amount of decentering of the optical axes between the first and second surfaces based on the shape measurement results of the top (i.e., first) and bottom (i.e., second) surfaces of an aspheric lens.

[0003] Here, use Figure 11 The lens measuring method of Patent Document 1 will be described. Figure 11 This is a diagram schematically showing a lens measuring device 101 disclosed in Patent Document 1.

[0004] The lens measurement device 101 consists of an optical probe 102 for measuring shape, a lens setting jig 104 that holds the lens to be inspected 103, and a camera 105. The optical probe 102 measures displacement using triangulation. Laser light emitted from a sensor unit 106 passes through a reflector 107 and is incident on an objective lens 108, irradiating the surface of the lens to be inspected 103. The laser light reflected by the surface of the lens to be inspected 103 is incident on the objective lens 108 again, detected by the sensor unit 106 via the reflector 107, and the displacement is measured.

[0005] The measurement of the lens under inspection 103 is performed as follows.

[0006] The lens to be inspected 103 is set on a lens setting jig 104 .

[0007] Next, the optical probe 102 is used to Figure 11 The lens setting jig 104 is scanned on the xy plane defined by the x-axis and y-axis to measure the surface shape of the first surface 103a of the inspection lens 103. Furthermore, the camera 105 measures pinholes 109 and 110 provided in the lens setting jig 104 via a reflector 107 and an objective lens 108 to determine the position of the lens setting jig 104 on the xy plane during measurement of the first surface of the inspection lens 103.

[0008] Next, the lens setting jig 104 is turned upside down and the shape of the second surface 103b of the lens 103 is measured using the optical probe 102. The position of the lens setting jig 104 on the xy plane during the measurement of the second surface of the lens 103 is also determined.

[0009] Finally, the amount of eccentricity of the optical axis of the first surface and the second surface can be calculated based on the respective center positions of the first surface and the second surface, and the positions of the lens setting jig 104 on the respective xy planes at the time of measurement of the first surface and the second surface, which are calculated based on the shapes of the first surface and the second surface of the lens under test 103.

[0010] Prior Art Documents

[0011] Patent Documents

[0012] Patent Document 1: International Publication No. 2007 / 018118 SUMMARY

[0013] A lens measurement method according to an embodiment of the present disclosure uses a shape measurement unit that measures a surface shape of a lens, and a transmission wave surface measurement unit that measures a transmission wave surface of the lens. The lens measurement method measures a surface shape of a first surface of the lens by the shape measurement unit, determines a center position of the first surface of the lens based on a measurement result, positions the lens at the transmission wave surface measurement unit based on the center position of the first surface of the lens and a relative position between the shape measurement unit and the transmission wave surface measurement unit, measures the transmission wave surface of the lens by the transmission wave surface measurement unit, and calculates an optical characteristic of the lens based on a measurement result of the transmission wave surface.

[0014] A lens measurement apparatus according to another embodiment of the present disclosure includes a shape measurement unit that measures a surface shape of a first surface of a lens, a shape measurement calculation unit that determines a center position of the first surface of the lens based on a measurement result by the shape measurement unit, a transmission wave surface measurement unit that measures a transmission wave surface of the lens positioned based on a relative position between the shape measurement unit and the lens and the center position of the first surface of the lens, and a calculation unit that calculates an optical characteristic of the lens based on a result of measuring the transmission wave surface of the lens by the transmission wave surface measurement unit. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 FIG. 1 is a diagram schematically showing a lens measurement apparatus according to an embodiment of the present disclosure.

[0016] Figure 2 FIG. 2 is a diagram schematically showing a relative position adjustment jig according to an embodiment of the present disclosure.

[0017] Figure 3 FIG. 3 is a flowchart illustrating a relative position adjustment method of a lens measurement apparatus according to an embodiment of the present disclosure.

[0018] Figure 4 FIG. 4 is a diagram schematically showing a shape measurement unit in the relative position adjustment method of the lens measurement apparatus according to an embodiment of the present disclosure.

[0019] Figure 5 This is a diagram schematically showing the relationship between the center of a reference sphere in a shape measurement section and a reference position of the shape measurement section in a relative position adjustment method of a lens measurement device according to an embodiment of the present disclosure.

[0020] Figure 6 This is a diagram schematically showing a transmission wavefront measuring section in a relative position adjustment method of a lens measuring device according to an embodiment of the present disclosure.

[0021] Figure 7 This is a diagram schematically showing the relationship between the center of the projection image of the reference sphere in the transmission wavefront measurement section and the reference position of the transmission wavefront measurement section in the relative position adjustment method of the lens measurement device according to the embodiment of the present disclosure.

[0022] Figure 8 This is a flowchart illustrating a lens measuring method of the lens measuring device according to the embodiment of the present disclosure.

[0023] Figure 9 It is a diagram schematically showing a lens measuring device according to a modified example of the embodiment of the present disclosure.

[0024] Figure 10 This is a diagram schematically showing a lens measuring device according to a modified example of the embodiment of the present disclosure when measuring a transmission wavefront.

[0025] Figure 11 This is a diagram schematically showing a lens measuring device disclosed in Patent Document 1. DETAILED DESCRIPTION

[0026] The lens measuring method disclosed in Patent Document 1 requires measuring the shape of the first surface of the lens 103 and then turning the lens 103 upside down to measure the shape of the second surface. This results in a problem of prolonged measurement time.

[0027] An object of one aspect of the present disclosure is to provide a lens measuring method and a lens measuring device capable of shortening the time required to measure optical characteristics of a lens.

[0028] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. Components common to the various drawings are denoted by the same reference numerals, and their description will be omitted as appropriate.

[0029] use Figure 1 A representative example of a lens measurement device according to an embodiment of the present disclosure will be described. Figure 1 It is a diagram schematically showing a lens measuring device 1 according to an embodiment of the present disclosure.

[0030] The lens measurement apparatus 1 has at least a shape measurement section 2, a transmitted wave surface measurement section 3, and a control device 4 having a shape measurement operation section 12 and an operation section 14.

[0031] The shape measurement section 2 measures the surface shape of the first surface 8a of the lens 8.

[0032] The shape measurement operation section 12 determines the center position of the first surface 8a of the lens 8 based on the measurement result in the shape measurement section 2.

[0033] The transmitted wave surface measurement section 3 measures the transmitted wave surface of the lens 8 positioned based on the relative position of the transmitted wave surface measurement section 3 to the shape measurement section 2 and the center position of the first surface 8a of the lens 8.

[0034] The operation section 14 calculates the optical characteristics of the lens 8 based on the result of measurement of the transmitted wave surface of the lens 8 by the transmitted wave surface measurement section 3.

[0035] These structures will be described in detail below.

[0036] The shape measurement section 2 is composed of a measurement probe 5, a lens setting section 6, and a transfer section 7, and the lens 8 to be measured is set in the lens setting section 6.

[0037] The measurement probe 5 measures the three-dimensional shape of the measurement target such as the lens 8 to be measured, and is scanned in the x, y, z axis directions to measure. Figure 1 The measurement probe 5 uses a contact type displacement measurement method, or a method using a laser triangulation or an interference measurement.

[0038] The lens setting section 6 is composed of a frame body provided with an opening section 6a so that light incident to the lens 8 to be measured set therein can be transmitted.

[0039] The transfer section 7 is an orthogonal robot or the like that transfers the lens setting section 6 in the x, y axis directions, and can move the lens setting section 6 between the measurement position of the shape measurement section 2 and the measurement position of the transmitted wave surface measurement section 3, and position the lens setting section 6 at the respective measurement positions of the shape measurement section 2 and the transmitted wave surface measurement section 3.

[0040] The transmitted wave surface measurement section 3 is composed of a light source 9, a wave surface sensor 10, the lens setting section 6 (illustrated in a dotted line) described in the shape measurement section 2, and the transfer section 7 (illustrated in a dotted line) described in the shape measurement section 2.

[0041] Here, the wave surface sensor 10 refers to a sensor that directly measures the distribution of the phase of the wave surface of light, and for example, a Shack-Hartmann sensor using a microlens array, a Fizeau interferometer, or a wave surface sensor using shearing interference based on a diffraction grating is used. In the present embodiment, as an example, a wave surface sensor using shearing interference based on a diffraction grating having a large dynamic range is used.

[0042] The light source 9 is a light source that emits parallel light 11, and in the present embodiment, a parallel light source with a wavelength of 635 nm is used as an example. Furthermore, the optical axis of the parallel light 11 (z-axis direction of the drawing) is adjusted to be perpendicular to the setting surface (xy-axis plane of the drawing) of the lenses 8 of the lens setting portion 6.

[0043] The control device 4 is a device that controls the lens measuring device 1, and has a shape measurement calculation portion 12, a transmitted wave surface measurement calculation portion 13, a calculation portion 14, a control portion 15, and a relative position storage portion 16. The control device 4 includes, for example, a processor and a memory connected to the processor. The functions of the control device 4 described below can also be realized by the processor executing a program stored in the memory.

[0044] The shape measurement calculation portion 12 calculates the three-dimensional shape of the measurement target object from the data measured by the measurement probe 5.

[0045] The transmitted wave surface measurement calculation portion 13 calculates the transmitted wave surface from the data measured by the wave surface sensor 10.

[0046] The calculation portion 14 controls the control device 4 to perform various calculations and instructions such as the relative position of the shape measurement portion 2 and the transmitted wave surface measurement portion 3.

[0047] The control portion 15 controls the transfer portion 7 to perform positioning of the lens setting portion 6.

[0048] The relative position storage portion 16 stores the relative position of the shape measurement portion 2 and the transmitted wave surface measurement portion 3.

[0049] In order to calculate the relative position of the shape measurement portion 2 and the transmitted wave surface measurement portion 3 of the lens measuring device 1, a relative position adjustment jig 17 that can be set in the lens setting portion 6 is used instead of the lens 8. Figure 2 FIG. 1 is a diagram schematically showing the relative position adjustment jig 17 of the embodiment of the present disclosure.

[0050] The relative position adjustment jig 17 has a reference sphere 18 as an example of a reference sphere portion, and an opening portion 19 as an example of a light transmission portion through which transmitted light passes is provided around the reference sphere 18. In the present embodiment, the reference sphere 18 is fixed by three support rods 20, 21, 22 that are arranged at equal angular intervals around the reference sphere 18 as an example.

[0051] In addition, the opening portion 19 can transmit light alone, and for example, the opening portion 19 can also be composed of glass that transmits light. In this case, the support rods 20, 21, 22 are not required.

[0052] The reference sphere 18 can be a steel ball or a ceramic ball, and its sphericity is preferably 1 μm or less. This is because, as will be described later, the relative position of the shape measurement unit 2 and the transmission wavefront measurement unit 3 is determined using the center position of the reference sphere 18, and therefore the sphericity of the reference sphere 18 must be highly accurate.

[0053] The diameter of the reference sphere 18 is set smaller than the vertical and horizontal dimensions of the image sensor of the wavefront sensor 10. This is so that the projection image of the reference sphere 18 can be measured by the wavefront sensor 10 as described later.

[0054] Next, use Figure 3 A method of obtaining the relative positions of the shape measuring section 2 and the transmission wavefront measuring section 3 of the lens measuring apparatus 1 will be described in order with reference to the flowchart of FIG. Figure 3 This is a flowchart illustrating a relative position adjustment method of the lens measurement device 1 according to the embodiment of the present disclosure.

[0055] First, in step S101, the relative position adjustment jig 17 is installed in the lens installation section 6 instead of the inspection lens 8. At this time, the relative position adjustment jig 17 is installed to arrange the reference sphere 18 in the opening 6a of the lens installation section 6.

[0056] Next, in step S102 , under the control of the control unit 15 , the relative position adjustment jig 17 is moved to the shape measuring unit 2 by the transfer unit 7 .

[0057] Figure 4 The figure schematically shows the shape measuring unit 2 in the relative position adjustment method of the lens measuring device 1 according to the embodiment of the present disclosure. The relative position adjustment jig 17 is positioned at a predetermined reference position of the shape measuring unit 2 by the transfer unit 7 under the control of the control unit 15 .

[0058] Next, in step S103 , the shape measuring unit 2 uses the measuring probe 5 to measure the shape of the reference sphere 18 of the relative position adjustment jig 17 , and the shape measurement calculation unit 12 calculates the center position of the reference sphere 18 based on the measurement result.

[0059] In this embodiment, as an example, the shape measurement calculation unit 12 determines the vertex position of the reference sphere 18 in the z-axis direction as the center position of the reference sphere 18. Regarding the vertex position of the reference sphere 18 in the z-axis direction, for example, the measurement probe 5 measures an arbitrary cross-section of the reference sphere 18 in the x-axis direction, and the shape measurement calculation unit 12 determines the x coordinate of the vertex in the z-axis direction. Furthermore, the shape measurement calculation unit 12 measures an arbitrary cross-section of the reference sphere 18 in the y-axis direction, and determines the y coordinate of the vertex in the z-axis direction. Thus, the shape measurement calculation unit 12 can determine the x and y coordinates of the center position of the reference sphere 18.

[0060] Alternatively, instead of this method, a method of scanning around the apex of the reference sphere 18 at equal intervals in the xy plane to find the coordinates of the z-axis direction in which the maximum is obtained can be used.

[0061] Using Figure 5 to explain the relationship between the center position of the reference sphere 18 and the given reference position of the shape measuring unit 2. Figure 5 is a diagram schematically showing the relationship between the center of the reference sphere 18 in the shape measuring unit 2 and the reference position of the shape measuring unit 2 in the relative position adjustment method of the lens measuring device 1 according to the embodiment of the present disclosure.

[0062] The coordinate system of the lens measuring device 1 is set as the x, y, z axes, and the coordinate system of the scanning direction of the shape measuring unit 2 is set as the H_f, V_f axes. In order to make the explanation simple, the x axis and the H_f axis, and the y axis and the V_f axis are set as the same directions, respectively. Furthermore, the origin position of the shape measuring unit 2 is set as O_f. The center position of the aforementioned reference sphere 18 is found as an offset amount from the origin position O_f of the shape measuring unit 2. The center position of the reference sphere 18 at this time is represented as the coordinates (ΔH_f, ΔV_f) of the coordinate system of the shape measuring unit 2. If the center position of the reference sphere 18 at the reference position of the shape measuring unit 2 is set as the coordinates (Xf, Yf) of the coordinate system of the lens measuring device 1, the coordinates (Xof, Yof) of the lens measuring device 1 of the origin position O_f of the shape measuring unit 2 can be represented by Equations (1) and (2).

[0063] Xof = Xf - ΔH_f (1)

[0064] Yof = Yf - ΔV_f (2)

[0065] Next, in step S104, the relative position adjustment jig 17 is moved from the shape measuring unit 2 to the transmission wavefront measuring unit 3 by the transfer unit 7 under the control of the control unit 15.

[0066] Figure 6 is a diagram schematically showing the transmission wavefront measuring unit 3 in the relative position adjustment method of the lens measuring device 1 according to the embodiment of the present disclosure. The relative position adjustment jig 17 is positioned at the given reference position of the transmission wavefront measuring unit 3 by the transfer unit 7 under the control of the control unit 15.

[0067] Next, in step S105, the projection image of the reference sphere 18 of the relative position adjustment jig 17 is measured by the transmission wavefront measuring unit 3, and the center position of the projection image is calculated from the measurement result by the transmission wavefront measurement calculation unit 13.

[0068] That is, in Figure 6In the transmission wavefront measurement section 3, parallel light 11 emitted from the light source 9 is measured by the wavefront sensor 10, with the light having transmitted the relative position adjustment jig 17.

[0069] Figure 7 FIG. 23 is a diagram schematically showing the relationship between the center position of the projection image of the reference sphere 18 in the transmission wavefront measurement section 3 in the relative position adjustment method of the lens measurement apparatus 1 according to the embodiment of the present disclosure and the reference position of the transmission wavefront measurement section 3. The image 23 measured by the wavefront sensor 10 represents the portion of the parallel light 11 that has transmitted the opening portion 19 of the relative position adjustment jig 17 as a bright image, and the portion that has not transmitted the parallel light 11 as a dark image. In the present embodiment, since the relative position adjustment jig 17 shown in FIG. 18 is used, the image 23 measured by the wavefront sensor 10 displays a bright portion 24 based on the opening portion 19 that has transmitted the parallel light 11, and displays the projection image 25 of the reference sphere 18, the projection images 26, 27, 28 of the support rods, and other dark portions 29 as dark portions. Figure 2

[0070] The coordinate system of the lens measurement apparatus 1 is set as the x, y, z axes, and the coordinate system of the image 23 measured by the wavefront sensor 10 of the transmission wavefront measurement section 3 is set as the H_w, V_w axes. In order to simplify the explanation, the x axis and the H_w axis, and the y axis and the V_w axis are respectively set in the same direction. Furthermore, the origin position of the transmission wavefront measurement section 3 is set as O_w. The center position of the projection image 25 of the reference sphere 18 described above is calculated as an offset amount from the origin position O_w of the transmission wavefront measurement section 3. The center position of the projection image 25 of the reference sphere 18 at this time is represented as the coordinates (ΔH_w, ΔV_w) of the coordinate system of the transmission wavefront measurement section 3.

[0071] The center position of the projection image 25 of the reference sphere 18 can be calculated by general image processing techniques. For example, the outline after the projection images 26, 27, 28 of the support rods 20, 21, 22 are removed from the projection image 25 of the reference sphere 18 is extracted, and the center when the outline is fitted to a circle is set as the center position of the projection image 25 of the reference sphere 18. Furthermore, by applying a filter for image processing such as smoothing in order to remove noise and the like contained in the projection image 25 of the reference sphere 18, the center position of the projection image 25 of the reference sphere 18 can be calculated with good accuracy.

[0072] Here, if the center position of the projection image 25 of the reference sphere 18 at the reference position of the transmission wavefront measurement section 3 is set as the coordinates (Xw, Yw) of the coordinate system of the lens measurement apparatus 1, the coordinates (Xow, Yow) of the origin position O_w of the transmission wavefront measurement section 3 in the coordinate system of the lens measurement apparatus 1 can be represented by Equations (3) and (4).

[0073] Xow = Xw - ΔH_w (3)​

[0074] Yow=Yw-ΔV_w (4)

[0075] Finally, in step S106 , the calculation unit 14 calculates the relative position of the shape measurement unit 2 and the transmission wavefront measurement unit 3 .

[0076] The relative position between the shape measurement unit 2 and the transmission wavefront measurement unit 3 can be determined by the calculation unit 14 based on the center position of the reference sphere 18 and the center position of the projection image of the reference sphere 18, that is, based on the difference between the coordinates (Xof, Yof) of the lens measurement device 1 at the origin position O_f of the shape measurement unit 2 and the coordinates (Xow, Yow) of the lens measurement device 1 at the origin position O_w of the transmission wavefront measurement unit 3. The relative position (ΔX, ΔY) between the shape measurement unit 2 and the transmission wavefront measurement unit 3 when the shape measurement unit 2 is used as the reference can be expressed by equations (1), (2), (3), and (4), and by equations (5) and (6).

[0077] ΔX=Xow-Xof (5)

[0078] ΔY=Yow-Yof (6)

[0079] If further expanded, it can be represented by equations (7) and (8).

[0080] ΔX=(Xw-Xf)-ΔH_w+ΔH_f (7)

[0081] ΔY=(Yw-Yf)-ΔV_w+ΔV_f (8)

[0082] Here, the first terms (Xw-Xf) and (Yw-Yf) on the right side of equations (7) and (8) can be accurately calculated as the amount of movement of transfer unit 7 from the predetermined reference position of shape measurement unit 2 to the predetermined reference position of transmission wavefront measurement unit 3. Furthermore, the second terms ΔH_w and ΔV_w can be calculated based on the center position of reference sphere 18, as described above. The third terms ΔH_f and ΔV_f can be calculated based on the center position of projection image 25 of reference sphere 18, as described above.

[0083] In this manner, the relative position between the shape measurement unit 2 and the transmission wavefront measurement unit 3 can be calculated with high accuracy using the relative position adjustment jig 17 .

[0084] Depend on Figure 1 The calculation unit 14 shown performs the above calculations to obtain the relative positions of the shape measurement unit 2 and the transmission wavefront measurement unit 3 , and stores the relative positions in the relative position storage unit 16 .

[0085] Next, use Figure 8A flowchart of a lens measurement method involved in an embodiment of the present disclosure will be described. Figure 8 A flowchart of a lens measurement method of a lens measurement apparatus 1 involved in an embodiment of the present disclosure will be described.

[0086] First, in step S201, the lens under test 8 is set in the lens setting portion 6.

[0087] Next, in step S202, the lens under test 8 set in the lens setting portion 6 is moved to the shape measurement portion 2 by the transfer portion 7 under the control of the control portion 15. That is, in the present embodiment, the lens under test 8 is moved to the shape measurement portion 2 by the transfer portion 7 under the control of the control portion 15. Figure 1 In the lens measurement apparatus 1 of the present embodiment, the lens under test 8 is positioned at a given measurement position of the shape measurement portion 2 by the transfer portion 7 under the control of the control portion 15.

[0088] Next, in step S203, the surface shape of the first surface 8a of the lens under test 8 is measured by the shape measurement portion 2, and the center position of the first surface 8a of the lens under test 8 is determined by the shape measurement calculation portion 12 based on the measurement result.

[0089] In the present embodiment, the surface 8a of the lens under test 8 facing the measurement probe 5 (the positive direction of the z-axis) is defined as the first surface of the lens under test 8. The surface shape of the first surface 8a of the lens under test 8 is scanned and measured by the measurement probe 5. In the present embodiment, the vertex position of the first surface 8a of the lens under test 8 in the z-axis direction is calculated as the center position of the first surface 8a of the lens under test 8 by the shape measurement calculation portion 12. As for the vertex position of the first surface 8a of the lens under test 8 in the z-axis direction, for example, an arbitrary x-axis cross section of the first surface 8a of the lens under test 8 is measured by the measurement probe 5, the x-coordinate of the z-axis direction that becomes the vertex is calculated, an arbitrary y-axis cross section of the first surface 8a of the lens under test 8 is measured, the y-coordinate of the z-axis direction that becomes the vertex is calculated, and thus the x, y coordinates of the center position of the first surface 8a of the lens under test 8 are calculated by the shape measurement calculation portion 12. Figure 1

[0090] In addition, in the present embodiment, as Figure 1 The first surface 8a of the lens under test 8 is described as an example of a lens that is convex in the positive direction of the z-axis as in the lens under test 8 illustrated in the drawing, but in the case where the first surface 8a of the lens under test 8 is concave in the negative direction of the z-axis, the position that becomes the vertex in the negative direction of the z-axis is calculated by the shape measurement calculation portion 12 and the x, y coordinates of the center position are calculated.

[0091] In addition, a method of scanning the vicinity of the vertex of the first surface 8a of the lens under test 8 at equal intervals on the xy-axis plane and calculating the coordinates of the vertex in the positive or negative direction of the z-axis by the shape measurement calculation portion 12 can also be adopted. ​

[0092] Further, in a case where the examined lens 8 is a complex aspherical shape, in the shape measurement operation section 12, aspherical data defined by the surface shape of the 1st surface 8a of the examined lens 8 measured and a design value can be fitted to find the center position of the aspherical shape, and set as the center position of the 1st surface 8a of the examined lens 8. By taking such a method, even in a lens in which the center position of the 1st surface 8a of the examined lens 8 cannot take a vertex in the positive or negative direction of the z-axis, the center position of the 1st surface 8a of the examined lens 8 can be correctly found by the shape measurement operation section 12.

[0093] Next, in step S204, the measurement position of the transmission wavefront measurement section 3 is calculated by the operation section 14 based on the center position of the 1st surface 8a of the examined lens 8 and the relative position of the shape measurement section 2 and the transmission wavefront measurement section 3.

[0094] In the present embodiment, the center position of the 1st surface 8a of the examined lens 8 is found as an offset amount from the origin position of the shape measurement section 2. At this time, the offset amount of the center position of the 1st surface 8a of the examined lens 8 from the origin position of the shape measurement section 2 is represented as (ΔX_fL, ΔY_fL). Further, the coordinates of the given measurement position of the shape measurement section 2 of the transfer section 7 are represented as (X_fm, Y_fm). Since the center position of the 1st surface 8a of the examined lens 8 is found as the offset amount from the origin position of the shape measurement section 2, the coordinates of the measurement position of the transmission wavefront measurement section 3 of the transfer section 7 in which the origin position of the transmission wavefront measurement section 3 and the center position of the 1st surface 8a of the examined lens 8 coincide in the transmission wavefront measurement section 3 can be represented by the following equations (9) and (10). Figure 3 The relative position (ΔX, ΔY) of the shape measurement section 2 and the transmission wavefront measurement section 3 stored in the relative position storage section 16 found in the flowchart of the relative position adjustment method is the difference of the origin position of the transmission wavefront measurement section 3 from the origin position of the shape measurement section 2 as a reference, and thus the coordinates (X_wm, Y_wm) of the measurement position of the transmission wavefront measurement section 3 of the transfer section 7 in which the origin position of the transmission wavefront measurement section 3 and the center position of the 1st surface 8a of the examined lens 8 coincide in the transmission wavefront measurement section 3 can be represented by the following equations (9) and (10).

[0095] X_wm = X_fm + ΔX - ΔX_fL (9)

[0096] Y_wm = Y_fm + ΔY - ΔY_fL (10)

[0097] Thus, the measurement position of the transmission wavefront measurement section 3 can be calculated by the operation section 14.

[0098] Next, in step S205, the examined lens 8 is moved to the transmission wavefront measurement section 3 by the transfer section 7 under the control of the control section 15.

[0099] That is, in the present embodiment, under the control of the control section 15, the inspection lens 8 is moved by the transfer section 7 to the coordinates of the measurement position of the transmission wavefront measuring section 3 calculated in step S204, whereby the center position of the first surface 8a of the inspection lens 8 is aligned with the origin position of the transmission wavefront measuring section 3.

[0100] Next, in step S206, the transmission wavefront of the inspection lens 8 is measured by the transmission wavefront measuring section 3, and the transmission wavefront is calculated by the transmission wavefront measuring and calculating section 13, and the optical characteristics are calculated by the calculating section 14 based on the calculation results.

[0101] That is, in the present embodiment, under the control of the control section 15, the inspection lens 8 is moved by the transfer section 7 to the coordinates of the measurement position of the transmission wavefront measuring section 3 calculated in step S204, whereby the center position of the first surface 8a of the inspection lens 8 is aligned with the origin position of the transmission wavefront measuring section 3. Figure 1 In the lens measuring apparatus 1 of the present embodiment, parallel light 11 is emitted from the light source 9, the light transmitted through the inspection lens 8 is received by the wavefront sensor 10, and the transmission wavefront is measured. In the transmission wavefront measuring and calculating section 13, the phase distribution of the measured transmission wavefront is fitted using Zernike polynomials, and Zernike coefficients are calculated, whereby aberration coefficients, which are information on the optical characteristics of the inspection lens 8, can be obtained.

[0102] In this case, in step S205, the effect of aligning the center position of the first surface 8a of the inspection lens 8 with the origin position of the transmission wavefront measuring section 3 is explained. In order to correctly measure the optical characteristics of the inspection lens 8, it is necessary to correctly align the optical axis of the ideal inspection lens 8 having no shape error with the center of the analysis circle for analyzing the transmission wavefront using Zernike polynomials. Regarding the aberration coefficients of the calculated optical characteristics, particularly the coma aberration, a large error is generated due to the deviation of the center of the analysis circle. As shown in the present embodiment, by positioning the inspection lens 8 by the transfer section 7 so that the center position of the first surface 8a of the inspection lens 8 is taken as the optical axis of the ideal inspection lens 8, whereby the center position of the first surface 8a of the inspection lens 8 is aligned with the origin position of the transmission wavefront measuring section 3, the optical axis of the ideal inspection lens 8 having no shape error can be correctly aligned with the center of the analysis circle, and the effect of being able to obtain the optical characteristics of the inspection lens 8 with high accuracy is obtained.

[0103] Further, in the present embodiment, no other optical components are disposed between the inspection lens 8 and the wavefront sensor 10. This is because, if other optical components are disposed between the inspection lens 8 and the wavefront sensor 10, the measurement accuracy is reduced due to the error of the optical characteristics or the error of the calibration of these optical components. Thus, the effect of being able to obtain the optical characteristics of the inspection lens 8 with high accuracy is obtained.

[0104] Further, in the present embodiment, the surface shape of the second surface of the subject lens 8 is not measured by the shape measuring section 2 as in the prior art, but the transmitted wave surface of the subject lens 8 is measured by the transmitted wave surface measuring section 3. The transmitted wave surface measurement can shorten the measurement time because it does not require scanning the measurement probe 5 as in the shape measurement. Thus, compared with the prior art, the shape measurement requiring the measurement time can be reduced to one time, and the lens measurement time can be shortened.

[0105] Further, in the present embodiment, unlike the prior art, the subject lens 8 does not need to be flipped upside down in order to measure the surface shapes of the first and second surfaces of the subject lens 8. For this reason, the process of flipping the subject lens 8 upside down can be omitted, and the lens measurement time can be shortened.

[0106] Finally, in step S207, the shape errors of the front and back surfaces of the subject lens 8 are discriminated by the arithmetic section 14 based on the optical characteristics.

[0107] That is, in the present embodiment, the discrimination of the shape errors of the front and back surfaces of the subject lens 8 is performed by the arithmetic section 14 using the correlation between the shape errors and the optical characteristics. For example, the error of the radius of curvature of the surface shape of the subject lens 8 is discriminated by the arithmetic section 14 using the correlation with the defocus or the spherical aberration of the aberration coefficient. Further, the amount of deviation of the center of the first surface 8a from the center of the second surface of the subject lens 8 in the in-plane direction (x-y axis plane) is discriminated by the arithmetic section 14 using the correlation with the coma aberration of the aberration coefficient. The correlation between each shape error and the optical characteristics can be obtained in advance from the results of simulation or prior experiments. By using the correlation between the shape errors and the optical characteristics obtained in advance by the arithmetic section 14 for the results of the optical characteristics obtained with high precision in step S206, the shape errors of the subject lens 8 can be discriminated by the arithmetic section 14. Figure 1

[0108] Further, the discrimination of the shape errors can be performed by the arithmetic section 14 in combination with the measurement results of the surface shape of the first surface 8a of the subject lens 8 measured by the shape measuring section 2. For example, in the arithmetic section 14, optical simulation is performed based on the measurement results of the surface shape of the first surface 8a of the subject lens 8, and comparison is performed with the results of the optical characteristics obtained with high precision in step S206, whereby the shape errors of the second surface of the subject lens 8 can be discriminated with higher precision.

[0109] ​Further, the shape error can be determined by the arithmetic unit 14 in combination with a result of measuring the objective lens 8 outside the lens measuring apparatus 1. For example, in the arithmetic unit 14, by performing optical simulation based on a result of measuring the thickness of the objective lens 8, a comparison is made with a result of the optical characteristics that are accurately obtained in step S206, whereby the error in the radius of curvature of the surface shape of the objective lens 8 can be determined with higher accuracy.

[0110] By performing the lens measuring method as described above, the optical characteristics of the objective lens 8 can be measured with high accuracy in a short time, and further, the shape error can be measured.

[0111] In addition, in the lens measuring apparatus 1 of Figure 2 , Figure 4 , Figure 6 , the reference sphere 18 of the relative position adjustment jig 17 is illustrated as a complete sphere as an example of the reference sphere portion, but the reference sphere portion can not be a complete sphere. For example, as another example of the reference sphere portion, the reference sphere 18 can have a shape such that a half sphere is provided on a surface area of one-half or more of the reference sphere 18, and the half sphere of the reference sphere 18 is disposed on the side of the measurement probe 5 of the shape measuring portion 2. In the flowchart of the relative position adjustment method of Figure 3 , the center position of the reference sphere 18 can be calculated by the shape measuring portion 2 using the shape of the reference sphere 18 of the relative position adjustment jig 17 measured by the measurement probe 5 in step S103, and the center position of the projection image of the reference sphere 18 of the relative position adjustment jig 17 can be calculated by the transmission wavefront measuring portion 3 in step S105. Specifically, the reference sphere 18 of the relative position adjustment jig 17 can have a half sphere on a surface area of one-half or more, and the half sphere of the reference sphere 18 of the relative position adjustment jig 17 can be disposed on the side of the measurement probe 5 of the shape measuring portion 2. By providing the reference sphere 18 in this shape, it becomes easy to fix the reference sphere 18 to the relative position adjustment jig 17, and the relative position adjustment jig 17 can be implemented inexpensively.

[0112] In addition, in the lens measuring apparatus 1 of Figure 1 , an example is shown in which the lens setting portion 6 is detachably mounted on the transfer portion 7, but the lens setting portion 6 can be fixed to the transfer portion 7.

[0113] Figure 9 is a diagram schematically showing a lens measuring apparatus 1A related to a modification example of the embodiment of the present disclosure. The difference from the structure of Figure 1 is that the measurement probe 5 and the wavefront sensor 10 can be mounted on and moved by the transfer portion 7. The lens setting portion 6 is fixed to the measurement apparatus setting table of the lens measuring apparatus 1A separately from the transfer portion 7, and the objective lens 8 is provided on the lens setting portion 6. Further, the light source 9 is fixedly disposed below the lens setting portion 6, for example, on the measurement apparatus setting table. Thus, when the measurement probe 5 is moved and positioned in opposition to the lens setting portion 6 by the transfer portion 7, a state in which the measurement probe 5 functions as the shape measuring portion 2 is achieved (seeFigure 9 ), when the wavefront sensor 10 is moved and positioned in opposition to the lens setting section 6 by the transfer section 7, a state in which the wavefront sensor 10 functions as the transmission wavefront measurement section 3 is achieved (see Figure 10 ).

[0114] Figure 9 The lens setting section 6 is positioned as a state in which the shape measurement section 2 functions. The measurement probe 5 is positioned at a measurement position of the lens setting section 6 by the transfer section 7, and the surface shape of the first face 8a of the lens under test 8 is measured by the measurement probe 5. At this time, the light source 9 does not emit light.

[0115] Figure 10 is a diagram schematically showing the lens measurement apparatus in the transmission wavefront measurement of the lens measurement apparatus 1A in the modification example of the embodiment of the present disclosure. Figure 10 The lens setting section 6 is positioned as a state in which the shape measurement section 2 functions. The measurement probe 5 is positioned at a measurement position of the lens setting section 6 by the transfer section 7, and the surface shape of the first face 8a of the lens under test 8 is measured by the measurement probe 5. At this time, the light source 9 does not emit light.

[0116] Further, the relative position of the measurement probe 5 mounted on the transfer section 7 and the wavefront sensor 10 is determined by the same method as the relative position adjustment method of the lens measurement apparatus 1 shown in Figure 3 .

[0117] Further, the measurement of the lens under test 8 is performed by the same method as the lens measurement method of the lens measurement apparatus 1 shown in Figure 8 .

[0118] By being configured as described above, the position of the lens under test 8 can be prevented from deviating due to vibration or the like at the time of transfer of the lens under test 8, and the lens under test 8 can be measured with high precision.

[0119] Hereinafter, various modes of the present disclosure will be described.

[0120] In the first mode of the present disclosure, a lens measurement method using a shape measurement section that measures the surface shape of a lens and a transmission wavefront measurement section that measures the transmission wavefront of the lens, measures the surface shape of a first face of the lens by the shape measurement section, determines the center position of the first face of the lens from the measurement result, positions the lens at the transmission wavefront measurement section based on the center position of the first face of the lens and the relative position of the shape measurement section and the transmission wavefront measurement section, measures the transmission wavefront of the lens by the transmission wavefront measurement section, and calculates the optical characteristics of the lens from the measurement result of the transmission wavefront.

[0121] In the second aspect of the present disclosure, on the basis of the lens measurement method described in the first aspect, the relative position is determined by the following steps: the center position of the reference sphere portion is calculated by measuring the reference sphere portion of the relative position adjustment jig provided with a light transmission portion that transmits light around the reference sphere portion by the shape measurement unit; the center position of the projection image of the reference sphere portion is calculated by measuring the reference sphere portion of the relative position adjustment jig by the transmission wavefront measurement unit; and the relative position of the shape measurement unit and the transmission wavefront measurement unit is determined based on the center position of the reference sphere portion and the center position of the projection image of the reference sphere portion.

[0122] In the third aspect of the present disclosure, on the basis of the lens measurement method described in the first or second aspect, after the optical characteristics of the lens are calculated, the shape error of the front and back surfaces of the lens is further determined based on the optical characteristics of the lens.

[0123] In the fourth aspect of the present disclosure, on the basis of the lens measurement method described in any one of the first to third aspects, the transmission wavefront measurement unit is composed of a light source of parallel light and a wavefront sensor that measures the distribution of the phase of the wavefront of light from the light source, and when the transmission wavefront is measured, the light from the light source is directly incident on the lens, and the light transmitted through the lens is directly incident on the wavefront sensor, and the transmission wavefront is measured by the wavefront sensor.

[0124] In the fifth aspect of the present disclosure, a lens measurement device includes: a shape measurement unit that measures the surface shape of a first surface of a lens; a shape measurement calculation unit that determines the center position of the first surface of the lens based on the measurement result of the shape measurement unit; a transmission wavefront measurement unit that measures the transmission wavefront of the lens positioned based on the relative position between the shape measurement unit and the center position of the first surface of the lens; and a calculation unit that calculates the optical characteristics of the lens based on the result of measuring the transmission wavefront of the lens by the transmission wavefront measurement unit.

[0125] In the sixth aspect of the present disclosure, on the basis of the lens measurement device described in the fifth aspect, there are provided: a lens placement portion in which the lens is placed in each of the shape measurement portion and the transmission wavefront measurement portion; a relative position adjustment jig provided with a reference spherical portion for determining the relative position of the shape measurement portion and the transmission wavefront measurement portion, and a light transmission portion that transmits light around the reference spherical portion, and capable of being placed in the lens placement portion in place of the lens; a relative position storage portion that stores the relative position of the shape measurement portion and the transmission wavefront measurement portion, the relative position being determined on the basis of the center position of the reference spherical portion obtained by measuring the reference spherical portion of the relative position adjustment jig with the shape measurement portion, and the center position of a projection image of the reference spherical portion obtained by measuring the reference spherical portion of the relative position adjustment jig with the transmission wavefront measurement portion; and a control portion that adjusts the positions of the shape measurement portion and the transmission wavefront measurement portion with respect to the lens placement portion, the calculation portion calculates the placement position of the lens in the transmission wavefront measurement portion on the basis of the center position of the first surface of the lens measured with the shape measurement portion and the relative position stored in the relative position storage portion, and the transmission wavefront measurement portion is configured with a parallel light source and a wavefront sensor that measures the distribution of the phase of the wavefront of light from the light source, the light from the light source is directly incident on the lens, and the light transmitted through the lens is directly incident on the wavefront sensor, and the transmitted wavefront is measured with the wavefront sensor.

[0126] In the seventh aspect of the present disclosure, on the basis of the lens measurement device described in the sixth aspect, the diameters of the reference spherical portions of the relative position adjustment jig are each smaller than the longitudinal dimension and the lateral dimension of the image sensor of the wavefront sensor of the transmission wavefront measurement portion.

[0127] In the eighth aspect of the present disclosure, on the basis of the lens measurement device described in the sixth or seventh aspect, the reference spherical portion of the relative position adjustment jig has a hemisphere on more than half of the surface area, and the hemisphere of the reference spherical portion of the relative position adjustment jig is disposed on the side of the measurement probe of the shape measurement portion.

[0128] In the ninth aspect of the present disclosure, on the basis of the lens measurement device described in any one of the sixth to eighth aspects, the light source of the transmission wavefront measurement portion and the lens placement portion are fixed, the measurement probe of the shape measurement portion and the wavefront sensor of the transmission wavefront measurement portion are placed in the same transfer portion, the measurement probe is opposed to the lens placement portion by moving the transfer portion when the shape measurement portion functions, and the wavefront sensor is opposed to the lens placement portion by moving the transfer portion when the transmission wavefront measurement portion functions.

[0129] In addition, by appropriately combining any of the various embodiments or modifications, the effects possessed by each can be obtained. Furthermore, combinations of embodiments with each other, or combinations of examples with each other, or combinations of embodiments and examples, can be made, and combinations of features of different embodiments or examples with each other can also be made.

[0130] According to the present disclosure, by performing shape measurement of only one face of a lens and without needing to flip the lens upside down, the time for measuring the optical characteristics such as wavefront aberration of the lens can be shortened.

[0131] Industrial applicability

[0132] The lens measurement method and lens measurement apparatus of the present disclosure can shorten the time for measuring the optical characteristics such as wavefront aberration of a lens, and are useful in measurement, adjustment, testing, or inspection in the manufacturing process of a single lens or a lens group.

[0133] Explanation of reference numerals

[0134] 1, 1A Lens measurement apparatus

[0135] 2 Shape measurement section

[0136] 3 Transmitted wavefront measurement section

[0137] 4 Control apparatus

[0138] 5 Measurement probe

[0139] 6 Lens setting section

[0140] 6a Opening

[0141] 7 Transfer section

[0142] 8 Lens under test

[0143] 8a First face

[0144] 9 Light source

[0145] 10 Wavefront sensor

[0146] 11 Parallel light

[0147] 12 Shape measurement calculation section

[0148] 13 Transmitted wavefront measurement calculation section

[0149] 14 Calculation section

[0150] 15 Control section

[0151] 16 Relative position storage section

[0152] 17 Relative position adjustment jig

[0153] 18 reference ball

[0154] 19 opening portion

[0155] 20 support rod

[0156] 21 support rod

[0157] 22 support rod

[0158] 23 image measured by wavefront sensor

[0159] 24 bright portion

[0160] 25 projected image of reference ball

[0161] 26 projected image of support rod

[0162] 27 projected image of support rod

[0163] 28 projected image of support rod

[0164] 29 other dark portion

[0165] 101 lens measuring device

[0166] 102 light probe

[0167] 103 lens under test

[0168] 104 lens setting jig

[0169] 105 camera

[0170] 106 sensor section

[0171] 107 mirror

[0172] 108 objective lens

[0173] 109 pinhole

[0174] 110 pinhole

Claims

1. A lens measuring method comprising: a shape measuring unit for measuring a surface shape of a lens; and a transmission wavefront measuring unit for measuring a transmission wavefront of the lens. The shape measuring unit measures the surface shape of the first surface of the lens, and determines the center position of the first surface of the lens based on the measurement result. positioning the lens in the transmission wavefront measurement section based on the center position of the first surface of the lens and the relative positions of the shape measurement section and the transmission wavefront measurement section, The transmission wavefront of the lens is measured by the transmission wavefront measuring unit, The optical characteristics of the lens are obtained based on the measurement results of the transmission wavefront.

2. The lens measuring method according to claim 1, wherein: The relative position is determined by the following process: The shape measuring unit measures the reference spherical portion of a relative position adjustment jig having a light transmitting portion for transmitting light around the reference spherical portion to obtain the center position of the reference spherical portion; The transmission wavefront measuring unit measures the reference spherical portion of the relative position adjustment jig to obtain the center position of the projection image of the reference spherical portion; and The relative positions of the shape measurement unit and the transmission wavefront measurement unit are determined based on the center position of the reference spherical unit and the center position of the projection image of the reference spherical unit.

3. The lens measuring method according to claim 1 or 2, wherein: After obtaining the optical characteristics of the lens, shape errors of the front and back surfaces of the lens are further determined based on the optical characteristics of the lens.

4. The lens measuring method according to claim 1 or 2, wherein: The transmission wavefront measuring unit is composed of a light source of parallel light and a wavefront sensor for measuring the phase distribution of the wavefront of the light from the light source. When measuring the transmission wavefront, the light from the light source is directly incident on the lens, and the light transmitted through the lens is directly incident on the wavefront sensor, and the transmission wavefront is measured by the wavefront sensor.

5. A lens measuring device comprising: a shape measuring unit for measuring a surface shape of a first surface of the lens; a shape measurement calculation unit that determines a center position of the first surface of the lens based on a measurement result obtained by the shape measurement unit; a transmission wavefront measuring unit configured to measure a transmission wavefront of the lens positioned based on a relative position with the shape measuring unit and the center position of the first surface of the lens; and The calculation unit obtains the optical characteristics of the lens based on the result of measuring the transmission wavefront of the lens by the transmission wavefront measurement unit.

6. The lens measuring device according to claim 5, wherein: The lens measuring device comprises: a lens setting section for setting the lenses in the shape measuring section and the transmission wavefront measuring section, respectively; a relative position adjustment jig including a reference spherical portion for determining the relative position of the shape measuring portion and the transmission wavefront measuring portion, and a light transmitting portion for transmitting light around the reference spherical portion, and capable of being installed in the lens installation portion in place of the lens; a relative position storage unit that stores a relative position between the shape measuring unit and the transmitted wavefront measuring unit, the relative position being determined based on a center position of the reference spherical portion obtained by measuring the reference spherical portion of the relative position adjustment jig by the shape measuring unit and a center position of a projection image of the reference spherical portion obtained by measuring the reference spherical portion of the relative position adjustment jig by the transmitted wavefront measuring unit; and a control unit that adjusts the positions of the shape measuring unit and the transmission wavefront measuring unit relative to the lens setting unit, The calculation unit calculates the installation position of the lens in the transmission wavefront measurement unit based on the center position of the first surface of the lens measured by the shape measurement unit and the relative position stored in the relative position storage unit, and The transmitted wavefront measuring unit is composed of a light source of parallel light and a wavefront sensor that measures the phase distribution of the wavefront of the light from the light source. The light from the light source is directly incident on the lens, and the light transmitted through the lens is directly incident on the wavefront sensor, and the transmitted wavefront is measured by the wavefront sensor.

7. The lens measuring device according to claim 6, wherein: The diameter of the reference spherical portion of the relative position adjustment jig is smaller than the longitudinal and lateral dimensions of the image sensor of the wavefront sensor of the transmission wavefront measurement unit.

8. The lens measuring device according to claim 6 or 7, wherein: The reference spherical portion of the relative position adjustment jig has a hemisphere at least half of its surface area, and the hemisphere of the reference spherical portion of the relative position adjustment jig is arranged on the measurement probe side of the shape measurement unit.

9. The lens measuring device according to claim 6 or 7, wherein: The light source and the lens setting portion of the transmission wavefront measurement section are fixed, and the measurement probe of the shape measurement section and the wavefront sensor of the transmission wavefront measurement section are provided on the same transfer section. When functioning as the shape measurement section, the measurement probe is moved by the transfer section so as to be opposed to the lens setting portion, and when functioning as the transmission wavefront measurement section, the wavefront sensor is moved by the transfer section so as to be opposed to the lens setting portion.

Images