JP2013253915A - Lens surface interval measurement device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a a lens surface interval measurement device that facilitates positioning of an optical axis of a measurement optical system with respect to a measured lens disposed outside the device, and enables measurement of a lens surface interval of the measured lens.SOLUTION: The lens surface interval measurement device comprises: a light source 1; a fiber coupler 2 that acts as a light flux division part and a light flux synthesis part; a light path length change part 16 that changes a light path length of a reference light flux L; a measurement optical part 30 that collects a measurement light flux Land irradiates a measured lens 10 with light; a light detection part 17 that detects light intensity of a synthesis light flux L; a supporting part 31 that includes a shift stage 32 and a gonio-stage 33; an operation input part 14; a movement control part that moves the measurement optical part 30; a separating distance measurement part that measures a separating distance between the measurement optical part 30 and a measured lens surface 10a; and a drive amount calculation part that calculates a distance between centers of a tilting center Q and a curvature center of the measured lens surface 10a from the separation distance and calculates a drive amount for rotating and moving the measurement optical part 30.

Description

  The present invention relates to a lens surface distance measuring device that measures the surface distance of lenses in a non-contact manner.

2. Description of the Related Art Conventionally, there has been proposed a lens surface distance measuring device that measures lens surface distance measurement or inner wall measurement in a non-contact manner using interference.
In such a lens surface distance measuring device, the light beam from the low-coherence light source is divided into two, and one light beam is irradiated to the lens surface through the measurement optical system so that the optical path length of the other light beam can be changed. Then, the reflected light beam reflected by the lens surface and collected by the measurement optical system is combined with the other light beam, and the light intensity of the combined light beam is detected. Since the light beam from the low-coherence light source has a short coherence length, interference occurs in a narrow region where the optical path length of the light beam reflected by the lens surface of the measurement optical system and the optical path length of the reference light beam substantially coincide with each other, and the interference light By detecting the peak value of the intensity, the position of the lens surface can be specified from the optical path length of the reference light beam at that time. For this reason, the surface interval of the lens to be measured can be measured.
In such a measurement, if the optical axis of the measurement optical system is deviated from the optical axis of the test lens, a measurement error of the surface separation occurs. Therefore, prior to the measurement of the surface separation, the optical axis of the measurement optical system It is necessary to make an adjustment to match the optical axis of the analyzing lens.
For example, in Patent Document 1, a test optical system is arranged on a stage, the amount of eccentricity of each surface is measured, the optical axis of the test optical system is calculated, and then the test optical system with respect to the measurement reference axis is measured by an automatic stage. A method for adjusting the posture of the camera has been proposed.
In Patent Document 1, a Twiman-Green interferometer using a low coherence light source is employed.

JP 2005-147703 A

However, the conventional lens surface distance measuring device as described above has the following problems.
In the technique described in Patent Document 1, shift and tilt adjustment of the optical axis of the lens to be measured is performed on the adjustment stage, and centering with the measurement optical axis is performed. For this reason, it is necessary to arrange the test lens on the adjustment stage when the lens surface distance is measured.
Therefore, for example, when measuring the lens thickness in the lens polishing step, it is necessary to remove the lens to be tested from the polishing machine and place it on the adjustment stage to measure the lens surface distance. If the amount of polishing is insufficient, it must be reattached to the polishing machine and reworked. In this case, if an attachment error occurs, there is a possibility that correct correction cannot be performed.
For this reason, there is a strong demand for a lens surface distance measuring device capable of accurately measuring the lens surface distance and the lens thickness even when the test lens is fixed to an apparatus such as a polishing machine.
In such a measurement, the position of the test lens cannot be adjusted accurately, so the measurement optical axis of the lens surface distance measuring device must be moved and placed at a position coaxial with the optical axis of the test lens. However, such adjustment is difficult with the conventional lens surface distance measuring device.
It is also possible to adjust the position and orientation of the entire lens surface distance measuring device by movably supporting it. However, since the shape is complicated, it is difficult to move compared to moving the lens under test. There is a problem that adjustment workability is poor.

  The present invention has been made in view of the above-described problems. The optical axis of the measurement optical system is easily positioned with respect to a test lens disposed outside the apparatus, and the lens surface interval of the test lens is determined. It is an object of the present invention to provide a lens surface distance measuring device capable of measuring

  In order to solve the above-described problems, in the invention according to claim 1, a light source, a light beam splitting unit that converts a light beam from the light source into a measurement light beam and a reference light beam, and an optical path that changes an optical path length of the reference light beam A length changing unit; a measuring optical unit that collects the measurement light beam and irradiates the lens to be examined; and condenses a reflected light beam from the test lens; a reflected light beam from the test lens; and the reference light beam A light beam combining unit that forms a combined light beam, a light detection unit that collects the combined light beam and detects the light intensity of the combined light beam, a translation mechanism that translates the measurement optical unit, By having a tilting mechanism that tilts the measurement optical unit, a support unit that supports the position and posture of the measurement optical unit so as to be adjustable, and an operation input unit capable of operating input for moving the measurement optical unit And the parallel movement based on the operation input A distance between the measurement optical unit and the lens surface of the lens to be measured on the optical axis between the movement control unit that controls the movement of the measurement optical unit by driving the tilt mechanism and the tilting mechanism; A distance measuring unit that measures a distance; and a center-to-center distance between a tilt center of the measurement optical unit and a center of curvature of the lens surface based on the separation distance; and the measurement optical unit of the lens surface A driving amount calculation unit configured to calculate a driving amount of the parallel movement mechanism and the tilting mechanism for rotating around the center of curvature;

  According to a second aspect of the present invention, in the lens surface distance measuring device according to the first aspect, a rotation angle for rotating the measurement optical unit around the center of curvature of the lens surface or the rotation of the operation input unit, When the rotational movement distance on the lens surface is input, the drive amount calculation unit calculates the drive amounts of the parallel movement mechanism and the tilt mechanism corresponding to the rotation angle or the rotation movement distance, and the drive It is set as the structure provided with the operation input auxiliary | assistance part which displays quantity.

  According to a third aspect of the present invention, in the lens surface interval measuring device according to the first or second aspect, the separation distance measuring unit is a reference disposed at a fixed position on the optical path of the measurement light beam in the measurement optical unit. When the optical path length of the reference light flux is changed by the optical element for optical and the optical path length changing unit, a change in light intensity due to interference between the optical surface of the reference optical element and the lens surface of the lens to be measured is detected. By doing so, the separation distance is calculated.

  According to a fourth aspect of the present invention, in the lens surface distance measuring device according to any one of the first to third aspects, the light beam splitting unit and the light beam combining unit include the light source, the optical path length changing unit, and A configuration is made of a fiber coupler connected to the measurement optical unit.

  According to a fifth aspect of the present invention, in the lens surface distance measurement device according to any one of the first to fourth aspects, the movement control unit includes the measurement optical unit disposed on the lens surface. The parallel movement mechanism corresponding to the rotation angle or the rotation movement distance by the drive amount calculation unit when a rotation angle for rotation movement about the center of curvature or a rotation movement distance on the lens surface is input. The driving amount of the tilting mechanism is calculated, and the parallel movement mechanism and the tilting mechanism are driven based on the driving amount.

  According to a sixth aspect of the present invention, in the lens surface distance measuring device according to the first or second aspect, the separation distance measuring unit includes a non-contact length measuring device provided in the measuring optical unit.

  According to the lens surface distance measuring device of the present invention, the measurement optical part that condenses the measurement light beam and irradiates the test lens, and condenses the reflected light beam from the test lens, is movably supported on the support part. By providing the separation distance measurement unit and the drive amount calculation unit, the measurement optical unit can be easily rotated around the center of curvature of the lens surface of the test lens. On the other hand, it is possible to easily position the optical axis of the measurement optical system and measure the distance between the lens surfaces of the test lens.

It is a typical system block diagram which shows the system configuration | structure of the lens surface distance measuring apparatus of the 1st Embodiment of this invention. It is a typical block diagram which shows the structure of the principal part of the lens surface distance measuring apparatus of the 1st Embodiment of this invention. It is a functional block diagram which shows the function structure of the control unit used for the lens surface space | interval measuring apparatus of the 1st Embodiment of this invention. It is operation | movement explanatory drawing explaining the optical axis alignment operation | movement of the lens surface distance measuring apparatus of the 1st Embodiment of this invention. A schematic graph showing a change in light intensity when the focus position is adjusted but not a normal incidence adjustment state, a partially enlarged view of a part A thereof, and a change in the light intensity when in a normal incidence adjustment state It is a typical graph. FIG. 5 is an operation explanatory diagram following FIG. 4. It is a typical graph which shows the change of the light intensity in case a measurement optical axis and a lens optical axis are coaxial. It is a typical block diagram which shows the structure of the principal part of the lens surface distance measuring apparatus of the 2nd Embodiment of this invention. It is a functional block diagram which shows the function structure of the control unit used for the lens surface space | interval measuring apparatus of the 2nd Embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. In all the drawings, even if the embodiments are different, the same or corresponding members are denoted by the same reference numerals, and common description is omitted.

[First Embodiment]
The lens surface distance measuring apparatus according to the first embodiment will be described.
FIG. 1 is a schematic system configuration diagram showing a system configuration of a lens surface distance measuring device according to a first embodiment of the present invention. FIG. 2 is a schematic configuration diagram showing the configuration of the main part of the lens surface distance measuring device according to the first embodiment of the present invention. FIG. 3 is a functional block diagram showing a functional configuration of a control unit used in the lens surface distance measuring device according to the first embodiment of the present invention.

As shown in FIG. 1, the lens surface distance measuring device 50 according to the present embodiment is a surface between a lens surface 10a to be tested and a lens back surface 10b to be tested, which is a lens surface of the lens 10 arranged outside the device. The distance is measured, that is, the lens thickness is measured.
Arrangement form of the lens 10, between the surface interval measurement, fixed position, and orientation is retained, subject lens surface 10a, and the measurement light beam L _m which will be described later in the test lens rear surface 10b, the reflected light beam There is no particular limitation as long as L _m ′ can be acquired.
In FIG. 1, as an example, an example in which the test lens 10 is in a state of being affixed on the polishing dish 19 is illustrated. As another example, although not particularly illustrated, for example, an arrangement form in which the test lens 10 after polishing or after molding is held on a conveyance pallet or a cleaning jig can be exemplified.
The type of the test lens 10 is not particularly limited, and an appropriate convex lens or concave lens can be adopted. However, the test lens 10 in FIG. 1 is schematically shown.
In the specific description of the measurement, it is easier to understand the assumption of the surface shape of the test lens front surface 10a and the test lens back surface 10b. Therefore, as shown in FIG. Description will be made assuming that the test lens front surface 10a and the test lens back surface 10b are biconvex lenses each having a convex spherical surface.

  The schematic configuration of the lens surface distance measuring device 50 includes a light source 1, a fiber coupler 2 (light beam splitting unit, light beam combining unit), an optical path length changing unit 16, a measuring optical unit 30, a support unit 31, a light detecting unit 17, and a control unit. 13 is provided.

The light source 1 employs an SLD (Super Luminescent Diode) that is a low-coherence light source.
The fiber coupler 2 has four ports, and fiber coupler end faces 2a, 2b, 2c, and 2d are formed as input / output ports at the tip of the optical fiber extended from each port.
For this reason, the fiber coupler 2 divides the light incident from the fiber coupler end surface 2a and emits the light to the fiber coupler end surfaces 2c and 2b, and combines the light incident from the fiber coupler end surfaces 2c and 2b to obtain the fiber coupler end surface 2d. Can be emitted.

The light source 1 is disposed in the vicinity of the fiber coupler end surface 2a so that the emitted light beam is incident on the fiber coupler end surface 2a.
For this reason, the light beam from the light source 1 incident on the fiber coupler 2 is split into a reference light beam L _r emitted from the fiber coupler end surface 2b and a measurement light beam L _m emitted from the fiber coupler end surface 2c. Therefore, the fiber coupler 2 constitutes a light beam splitting unit.

The optical path length changing unit 16 is a device portion that changes the optical path length of the reference light beam L _r by changing the folding position and re-entering the fiber beam end surface 2 b with the reference light beam L _r emitted from the fiber coupler end surface 2 b. .
The schematic configuration of the optical path length changing unit 16 includes a collimating lens 3, a reference mirror 5, a linear motion stage 4, and a linear scale 6 in a housing (not shown).

Collimator lens 3 is an optical element to parallel light flux reference light beam L _r emitted from the fiber coupler end face 2b.
Reference mirror 5 is a plane mirror for reflecting the reference light beam L _r is returned to the fiber coupler end surface 2b, the optical axis of the reference light beam L _r is supported on the linear stage 4 in a posture in which perpendicularly incident, linear stage by 4, it is provided to be movable along the optical axis of the reference light beam L _r.
Linear stage 4, for example, those with a linear motion mechanism such as a feed screw mechanism or a linear motor, movably supported in a direction along the reference mirror 5 to the optical axis of the reference light beam L _r.
The linear scale 6 acquires information on the movement position of the reference mirror 5 moved by the linear motion stage 4 and outputs the information on the movement position to the control unit 13.
The linear motion stage 4 and the linear scale 6 are communicably connected to the control unit 13, and their operations are controlled by control signals from the control unit 13.

Measuring optical unit 30 condenses the measuring beam L _m emitted from the fiber coupler end surface 2c was irradiated to the lens 10, condenses the reflected light beam L _{m 'from} the lens 10, fiber coupler It is a device portion that re-enters the end face 2c.
Schematic configuration of the measurement optical unit 30, the movable supported housing 30b by a support part 31 is provided separately from the not shown housing of the optical path length changing unit 16 includes a measurement optical system 30a, the measurement light beam L _m The separation distance measurement unit 34 is provided on the tip side in the emission direction.

The housing 30b, and fiber coupler end face 2c is fixed, the measurement light beam L _m emitted from the fiber coupler end face 2c is guided to the housing 30b.
Measurement optical system 30a includes a collimator lens 7 for collimated by converging the emitted measurement light beam L _m from the fiber coupler end faces 2c, collimated measurement luminous beam L _m condenses with test lens 10 And a condensing lens 8 for irradiating the light.
The position of the measurement optical system 30a is fixed with respect to the housing 30b. For this reason, the relative positional relationship between the measurement optical axis P, which is the optical axis of the measurement optical system 30a, and the housing 30b is fixed.
In particular, the condenser lens 8 is fixed to a lens holding portion 30 c provided on the distal end side of the measurement optical unit 30.

The separation distance measurement unit 34 measures a separation distance on the measurement optical axis P between the measurement optical unit 30 and the lens surface of the lens 10 to be tested.
The configuration of the separation distance measurement unit 34 is not particularly limited as long as such a separation distance can be measured. As an example, the separation distance measuring unit 34 of the present embodiment is a parallel plate in which the relative positional relationship between the housing 30b and the condenser lens 8 is fixed at a fixed position separated from the condenser lens 8, as shown in FIG. An example using 20 (reference optical element) will be described.
The parallel plate 20 has a surface interval between the first surface 20a facing the condenser lens 8 and the second surface 20b which is the back surface thereof and directed to the lens 10 to be tested. It is a glass flat plate different from the element spacing.
The parallel plate 20 is fixed to the tip of the lens holding portion 30c, and is thereby fixed at a position away from the condensing lens 8 by a certain distance between the condensing lens 8 and the test lens 10. Yes.
A method for measuring the separation distance using the parallel plate 20 will be described in the operation description to be described later.

  The support unit 31 supports the measurement optical unit 30 so that the position and posture of the measurement optical unit 30 with respect to the lens 10 can be adjusted. In the present embodiment, the support unit 31 includes a magnet stand 31a, a support arm 31b, a shift stage 32 (parallel movement mechanism), and A gonio stage 33 (tilting mechanism) is provided.

The magnet stand 31a is a base part for detachably fixing the support part 31 on a fixed plate 40 made of a magnetic material disposed near the lens 10 to be examined.
As the fixed platen 40, an appropriate member having a stable positional relationship with the lens 10 to be examined can be employed. For example, when the test lens 10 is fixed on the lens polishing machine, it is possible to use a rigid housing or work table of the lens polishing machine near the polishing dish 19 to which the test lens 10 is fixed. it can.

The support arm 31b is a support member for disposing the measurement optical unit 30 at a position and posture for measuring a surface interval and being separated from the magnet stand 31a, and the length, direction, and the like can be changed. .
In this embodiment, since the measurement optical unit 30 is lightweight, a flexible arm as shown in FIG. 2 is adopted as a specific example of the support arm 31b. However, the configuration of the support arm 31b is not limited thereto, and may be a configuration in which a plurality of rods, clamps, joints, and the like are combined.

The shift stage 32 is a moving stage that is fixed to the end of the support arm 31b opposite to the magnet stand 31a and is provided so as to be able to translate in three axial directions orthogonal to each other. For example, a combination of three single-axis stages is combined. An XYZ stage can be employed. Further, in order to increase the degree of freedom of arrangement of the measurement optical unit 30, in addition to these parallel movement stages, a rotation stage that rotates around the central axis of the support arm 31b may be combined.
In the present embodiment, as shown in FIG. 1, the shift stage 32 is connected to the control unit 13 so as to be communicable, and is driven by a control signal from the control unit 13.

The gonio stage 33 is fixed on the shift stage 32, and as shown in FIG. 2, the gonio stage 33 can be tilted around the tilt center Q in two planes including the measurement optical axis P and orthogonal to each other. It is a tilting stage.
The tilt center Q may not be on the measurement optical axis P as long as the relative positional relationship with the measurement optical axis P is known, but in order to make conversion of the driving amount at the time of measurement easier, which will be described later. It is preferable to be located on the measurement optical axis P.

  In the present embodiment, when the gonio stage 33 is driven to the reference position for each tilt, the measurement optical axis P is parallel to the moving direction of the one-axis stage of the shift stage 32 and is one axis orthogonal to the one-axis stage. It is arranged in parallel to a moving plane composed of a stage. Further, the tilt center Q of the gonio stage 33 is located on the measurement optical axis P.

Light detection unit 17, as shown in FIG. 1, in which by condensing the combined light beams L _c emitted from the fiber coupler end face 2d of the fiber coupler 2, for detecting the light intensity of the combined light beam L _c.
The combined light beam L _c is composed of the reference light beam L _r re-entered on the fiber coupler end surface 2b and the reflected light beam L _m ′ reflected from the measurement light beam L _m on the test lens 10 and re-entered on the fiber coupler end surface 2c. Light flux. For this reason, the fiber coupler 2 constitutes a light beam combining unit.

Schematic configuration of an optical detection unit 17, a photodiode 12 for receiving a condenser lens 11 for condensing the combined light beams L _c emitted from the fiber coupler end face 2d, the collected synthetic light beam L _c by the condenser lens 11 With.

  The functional configuration of the control unit 13 is for performing operation control of the lens surface distance measuring device 50 and computation for surface distance. As shown in FIG. 3, the measurement control unit 100, the data acquisition unit 101, and movement control are performed. Unit 102, drive amount calculation unit 103, surface interval calculation unit 104, and separation distance calculation unit 105.

The measurement control unit 100 is for performing overall control of the lens surface distance measurement device 50, and includes a data acquisition unit 101, a movement control unit 102, a drive amount calculation unit 103, a surface distance calculation unit 104, and the like in the control unit 13. It is communicably connected to the separation distance calculation unit 105, and can send a control signal to each of them or acquire a calculation result from each.
In addition, the measurement control unit 100 includes an operation input unit 14 for an operator to input an operation to control the operation of the lens surface distance measuring device 50, and information on the control and calculation results performed by the control unit 13. The display unit 15 that displays images and the like and the optical path length changing unit 16 are electrically connected.

The operation input unit 14 includes operation input means such as a keyboard, a mouse, and operation buttons, for example. In addition, the operation input of the operation input unit 14 is configured by configuring the display screen 15a (see FIG. 1) of the display unit 15 with a touch panel or the like and displaying an appropriate GUI on the display screen 15a. It may be configured to operate with a finger or the like.
Examples of the operation input performed by the operator include starting and stopping the lens surface distance measuring device 50 and driving the shift stage 32 and the gonio stage 33 to move the measurement optical unit 30 relative to the lens 10 to be measured. The operation input of the movement position can be mentioned.
Each operation input is converted into a control signal or numerical information as necessary, and sent to the measurement control unit 100.

  As shown in FIG. 3, the data acquisition unit 101 is electrically connected to the photodiode 12, acquires the output of the photodiode 12, A / D converts this output, and sends it to the measurement control unit 100. is there.

  The movement control unit 102 is communicably connected to the shift stage 32 and the gonio stage 33, and drives the shift stage 32 and the gonio stage 33 based on the control signal sent from the measurement control unit 100 and information on the driving amount. It is.

  The drive amount calculation unit 103 calculates the drive amounts of the shift stage 32 and the gonio stage 33 from the information on the movement position of the measurement optical unit 30 sent from the measurement control unit 100 based on the operation input from the operation input unit 14. Is.

In particular, the drive amount calculation unit 103 determines the measurement optical unit based on the separation distance on the measurement optical axis P between the measurement optical unit 30 and the test lens front surface 10a (the test lens back surface 10b) of the test lens 10. The center-to-center distance between the tilt center Q of 30 and the center of curvature O _a (O _b ) of the lens surface 10 a (test lens back surface 10 _b ) is calculated, and measured with the center of curvature O _a (O _b ) as the center. The drive amount of the shift stage 32 and the gonio stage 33 for rotating the optical unit 30 (hereinafter referred to as “rotational motion drive amount”) can be calculated.

Note that the information on the rotational movement amount of the measurement optical unit 30 may be a rotation angle centered on the center of curvature O _a (O _b ) or the shortest movement length on the test lens surface 10a (test lens back surface 10b). It may be. Here, the shortest movement length on the test lens surface 10a (the test lens back surface 10b) is a large circle (spherical center) of each spherical surface at two points on the test lens surface 10a (the test lens back surface 10b). Arc length when connected by a circle that intersects the plane passing through

Since the rotation angle and the shortest moving length on the lens surface correspond one-to-one if the radius of curvature of the lens surface is known, conversion between each other is easy. For example, when the input is performed with the shortest movement length, when the rotational movement amount of the measurement optical axis P approaches the target value, the magnitude of the error can be grasped with a sense of distance, so that it is easy for some operators to input the operation. There is.
For the sake of simplicity, the following description will be given using an example in which the operator inputs a rotation angle.

The rotational movement drive amount calculated by the drive amount calculation unit 103 is sent to the measurement control unit 100 and displayed on the display unit 15 by the measurement control unit 100.
For this reason, the operator can see the rotational movement drive amount with respect to the rotation angle input by the operation by looking at the display unit 15.

Therefore, the rotation angle for rotating the measurement optical unit 30 around the curvature center O _a (O _b ) of the test lens surface 10 a (the test lens back surface 10 _b ) or the test lens surface to the operation input unit 14. When the shortest movement length of 10a (back surface 10b to be examined) is input, the driving amount calculation unit 103 calculates the rotational movement driving amount corresponding to the rotation angle or the shortest movement length, and this rotational movement driving amount. The operation input auxiliary unit 107 is displayed.

  The surface interval calculation unit 104 calculates the surface interval between the lens front surface 10a and the lens rear surface 10b based on the signal change in the light intensity of the photodiode 12 sent from the measurement control unit 100, and performs measurement control. The data is sent to the unit 100.

The separation distance calculation unit 105 determines the first surface 20a and the second surface 20b of the parallel plate 20 and the test lens surface 10a (the test lens back surface 10b) from the light intensity signal of the photodiode 12 sent from the measurement control unit 100. ), And the distance on the measurement optical axis P from the first surface 20a or the second surface 20b to the test lens surface 10a (the test lens back surface 10b) is calculated. is there.
The separation distance may be measured from any position on the measurement optical unit 30, and the lens surface may be either the test lens front surface 10a or the test lens back surface 10b. Hereinafter, as an example, a description will be given of an example in which the distance from the second surface 20b to the lens surface 10a to be measured is the separation distance c (see FIG. 2).

  As described above, the present embodiment is an example in the case where the separation distance measurement unit 34 includes the parallel plate 20, the separation distance calculation unit 105, and the measurement control unit 100.

  The device configuration of the control unit 13 includes a computer including a CPU, a memory, an input / output interface, an external storage device, and the like, and the computer executes a control program and an arithmetic program corresponding to each function described above. It has become.

Next, the operation of the lens surface distance measuring device 50 will be described focusing on the optical axis alignment operation between the lens optical axis O ₀ of the lens 10 to be measured and the measurement optical axis P.
4A, 4B, and 4C are operation explanatory views for explaining the optical axis alignment operation of the lens surface distance measuring device according to the first embodiment of the present invention. FIG. 5A is a schematic graph showing a change in light intensity in a focus position adjustment state described later and not in a vertical incidence adjustment state described later. FIG.5 (b) is the elements on larger scale of the A section in Fig.5 (a). FIG. 5C is a schematic graph showing a change in light intensity in the normal incidence adjustment state. The horizontal axis of each graph is the optical path length of the reference light beam, and the vertical axis is the light intensity. 6 (a), 6 (b), and 6 (c) are explanatory diagrams of operations following FIG. 4 (c).

In order to measure the surface distance of the lens 10 to be measured by the lens surface distance measuring device 50, first, as shown in FIG. 1, the support portion 31 is fixed to the stationary platen 40 in the vicinity of the lens 10 to be tested.
Next, the operator inputs an operation from the operation input unit 14 and activates the lens surface distance measuring device 50 to initialize the positions of the shift stage 32 and the gonio stage 33 to the reference positions for translation and tilt, respectively. I do.
Further, for use in the calculation described later, the curvature radius R _{a of} the test lens surface 10 a, the curvature radius R _b of the test lens back surface 10 _b , and the refractive index n of the glass material of the test lens 10 are input. These values are stored by the measurement control unit 100 together with the preset mounting position of the parallel plate 20 and the position coordinates of the tilt center Q of the gonio stage 33 and are shared as parameters within the control unit 13.

Next, the operator moves the support arm 31b so that the combined focal position F of the optical system including the measurement optical system 30a and the parallel plate 20 is the apex p _{a of the} test lens surface 10a (the test lens surface 10a and the lens). while positioned in the vicinity of the intersection) of the optical axis L _0, the incident angle to the sample lens surface 10a of the measurement optical axis P is in a substantially 0 °, performs approximate alignment.
At this time, the lens surface 10a to be examined is adjusted with priority given to being located within the focal depth with respect to the synthetic focal position F.
Accordingly, as exaggeratedly shown in FIG. 4A, the incident angle of the measurement optical axis P with respect to the test lens surface 10a does not become 0 °, and the intersection S between the measurement optical axis P and the test lens surface 10a is it may be offset from the surface apex p _a.
In the following, except for a case where it is specifically expressed, for the sake of simplicity, “the combined focal position F of the optical system including the measurement optical system 30a and the parallel plate 20” is simply referred to as “ These are referred to as “the focal position F of the measurement optical system 30a”, “the focal position F of the condenser lens 8”, and the like.
In the present embodiment, “the combined focal position F of the optical system including the measurement optical system 30 a and the parallel plate 20” is a position obtained by shifting the strict meaning “focal position of the condenser lens 8” by the amount lifted by the parallel plate 20. It is.

Next, optical axis alignment is performed in which the measurement optical axis P and the lens optical axis O ₀ are arranged coaxially.
First, prior to the description of the operation, the optical path in the lens surface distance measuring device 50 and the magnitude of the light intensity output from the photodiode 12 will be described.

The light flux emitted from the light source 1 is incident on the fiber coupler end surface 2a, by a fiber coupler 2, and the reference light beam L _r, is split into a measuring beam L _m.
The reference light beam L _r is emitted from the fiber coupler end face 2 b through the optical fiber into the optical path length changing unit 16, is condensed by the collimator lens 3, becomes a parallel light beam, and reaches the reference mirror 5 when it reaches the reference mirror 5. It is perpendicularly incident and folded along the optical axis.
Then, the light is condensed by the collimator lens 3, reenters the fiber coupler end surface 2 b, and returns to the fiber coupler 2. At this time, if the position of the reference mirror 5 is changed by the linear motion stage 4, the optical path length of the reference light beam L _r changes by twice the amount of movement of the reference mirror 5.
The change amount of the optical path length is sequentially detected by the linear scale 6 and sent to the measurement control unit 100.

The measurement light beam L _m is emitted from the fiber coupler end face 2 c through the optical fiber into the housing 30 b of the measurement optical unit 30, is condensed by the collimator lens 7, becomes a parallel light beam, and reaches the condensing lens 8. As shown in FIG. 2, the light is condensed by the condensing lens 8, passes through the parallel plate 20, and is condensed at the focal position F of the condensing lens 8.
The measurement light beam L _m, when passing through the parallel plate 20, the first surface 20a, respectively, are reflected part respectively by the second surface 20b, the flow returns to the condenser lens 8 side. The measuring beam L _m is the collimator lens 7 via the fiber coupler end faces 2c, returns to the fiber coupler 2, is combined with the reference light beam L _r, it is emitted from the fiber coupler end surface 2d.

Measuring beam L _m which is focused on the subject lens surface 10a, as shown in FIG. 4 (a), the focal depth of the measurement optical axis P and the sample lens surface 10a of the intersection S condensing lens 8 For this reason, the reflected light beam L _m ′ on the lens surface 10a to be tested moves substantially backward in the optical path. Then, of the reflected light beam L _m ′, the light incident within the aperture angle range of the condenser lens 8 returns to the condenser lens 8 side and passes through the collimator lens 7 to form a spot on the fiber coupler end surface 2c. Form. For this reason, a part of the reflected light beam L _m ′ returns to the fiber coupler 2 and is combined with the reference light beam L _r to be emitted from the fiber coupler end surface 2d.
At this time, the light quantity of the reflected light beam L _m ′ emitted from the end face 2d of the fiber coupler is such that the measurement optical axis P coincides with the normal direction of the lens surface 10a and the focal position F of the condenser lens 8 is detected. Maximum when matched with the lens surface 10a.

Thus, from the fiber coupler end face 2d, the reference light beam L _r, the first surface 20a of the parallel plate 20, a part of the reflected light beam at the second surface 20b, and a portion of the reflected light beam L _{m ',} superposed composite light beam L _c is emitted. The combined light beam L _c is condensed by the condenser lens 11, enters the photodiode 12.
Photodiode 12 detects the light intensity of the combined light beams L _c, and sends the measurement control section 100 of the control unit 13.

In the present embodiment, since the light source 1 is a low-coherence light source, when the optical path length of the reference light beam L _r is changed, the light beam component substantially coincides with the optical path length of the reference light beam L _{r in} the combined light beam L _c. Interference occurs and appears as a change in light intensity.
Here, the optical path length of the reference light beam L _r, the division position of the reference light beam L _r is the fiber coupler 2 is formed, is reflected by the reference mirror 5 to return to the fiber coupler 2, the fiber within the fiber coupler 2 It means the optical path length from the coupler end surface 2b to the combined position where it is combined with the incident light beam.
Optical path length in which a corresponding measuring optical unit 30 side, likewise from the dividing position of the measuring beam L _m is the fiber coupler 2 is formed, is reflected by the reflecting surface of the measurement optical unit 30 in the fiber coupler 2 return means light path length to the synthetic position is combined with the return light of the reference light beam L _r in the fiber coupler 2.
In the following, unless otherwise specified, when the optical path length on the measurement optical unit 30 side is generically referred to, it is simply referred to as “the optical path length of the measurement light beam L _m ”. identify the surface, for example, it will be referred to as "optical path length of the measurement beam L _m to the sample lens surface 10a reflecting surface".

Measurement control section 100 sends a control signal to the optical path length changing unit 16, the optical path length of the reference light beam L _r is a short optical path length than the optical path length of the measurement beam L _m of the first surface 20a and the reflective surface , the sample lens rear surface 10b to the longer optical path length than the optical path length of the measurement beam L _m of the reflection surface, sequentially changing.

Thereby, for example, as shown in FIG. 4A, when the focal position F of the condensing lens 8 coincides with the lens surface 10a to be measured, when the output of the photodiode 12 is acquired, the photodiode 12 is obtained. The output of FIG. 5 shows a change like the graph shown in FIG.
In other words, the position d ₁ where the optical path length of the reference light beam L _r coincides with the optical path length of the measurement light beam L _m with the first surface 20a of the parallel plate 20 as the reflection surface, and the measurement with the second surface 20b as the reflection surface. and position d ₂ which is coincident with the optical path length of the light beam L _m, and the position d ₃ which is coincident with the optical path length of the measurement beam L _m of the reflection surface of the sample lens surface 10a, measurements of the sample lens surface 10b and the reflecting surface in the position d ₄ which coincide with the optical path length of the light beam L _m, the peak of the light intensity is observed.
FIG. 5 (a) (same for FIG. 5 (c)) is schematically shown. FIG. 5 (b) shows the state in the vicinity of each peak in an enlarged scale on the horizontal axis. As shown by the curve, the light intensity changes periodically from a constant value, and the magnitude of the upper and lower peak deviations increase and decrease after reaching the peak value.
The periodic repetition corresponds to the intensity of light due to interference, and the width of such change corresponds to the coherence length of the light source 1.

In FIG. 5A, the peak values at the positions d ₁ and d ₂ are such that the measurement light beam L _m reflected by the parallel plate 20 whose positional relationship with the measurement optical system 30a is fixed interferes with the reference light beam L _r. Therefore, it is constant regardless of the positional relationship between the measurement optical unit 30 and the test lens 10.
On the other hand, the peak values at the positions d ₃ and d ₄ vary depending on the positional relationship between the measurement optical unit 30 and the test lens front surface 10a and the test lens back surface 10b.

For example, the maximum when the incident angle to the sample lens surface 10a of the measuring beam L peak value by _m the measurement optical axis P of the reflecting surface of the sample lens surface 10a is 0 °. When the incident angle is larger than 0 °, the reflected light beam L _m ′ incident on the aperture angle range of the condenser lens 8 is reduced. Therefore, in the state of FIG. 4A, the peak value I _a at the position d ₃ is I _a1 is lower than the maximum value I _a0 described later.
Further, the measurement light beam L _m having the reflection surface of the test lens back surface 10b as a reflection surface has a large spot diameter on the test lens back surface 10b and a large incident angle to the test lens back surface 10b, and therefore returns to the condenser lens 8. Since the amount of light contained in the combined light beam L _c is reduced, the peak value becomes very low as I _b1 (where I _a1 > I _b1 ).

Further, as shown in FIG. 4B, the measurement optical axis P is in _a positional relationship passing through the center of curvature Oa of the test lens surface 10a, and the incident angle of the measurement optical axis P with respect to the test lens surface 10a is 0 °. becomes, as shown in FIG. 5 (c), the peak value of the position _{d 3} is the maximum value _{I a0 (However, I a0>} I _a1) becomes.
At this time, the peak value at the position d ₄ is slightly improved to be I _b2 (where I _b1 <I _b2 <I _a0 ).
Thus, by observing the peak values at the positions d ₃ and d ₄ , it is possible to determine the positional relationship between the measurement optical unit 30, the test lens front surface 10 a, and the test lens back surface 10 b.

Further, the optical path length of the reference light beam L _r where each peak value is generated represents the position on the measurement optical axis P of each reflection surface in the measurement optical unit 30.
Therefore, d ₂ -d ₁ is an optical path length corresponding to the plate thickness of the parallel plate 20, and d ₃ -d ₂ is a distance on the measurement optical axis P between the second surface 20 b and the lens surface 10 a to be measured. Yes, the separation distance c of this embodiment (see FIG. 2).
D ₄ -d ₃ is an optical path length corresponding to the distance between the test lens front surface 10 a and the test lens back surface 10 b on the measurement optical axis P, and the position where the measurement optical axis P intersects the test lens 10. It depends on.
In a state where the measurement optical axis P is aligned with the lens optical axis O ₀ , d ₄ -d ₃ is an optical path length corresponding to the surface interval between the test lens front surface 10 a and the test lens back surface 10 b. By dividing d ₄ -d ₃ by the known refractive index n of the glass material of the test lens 10, the surface interval between the test lens front surface 10 a and the test lens back surface 10 b can be calculated.

Here, the description returns to the optical axis alignment operation.
First, the measurement optical unit 30 that is roughly arranged is moved in the direction along the measurement optical axis P, and adjustment is performed to make the focal position F of the condenser lens 8 coincide with the lens surface 10a.
This movement is performed when the operator determines the amount of movement including the direction of the parallel movement in the direction along the measurement optical axis P and inputs an operation from the operation input unit 14.
The measurement control unit 100 sends the movement amount to the drive amount calculation unit 103 in order to drive the shift stage 32 based on the operation input from the operation input unit 14.
The measurement control section 100, the optical path length changing unit 16 drives the linear movement stage 4, keep moving the reference mirror 5 at a position where interference does not occur between the reference light beam L _r and the measurement light beam L _m by. As a result, the output from the photodiode 12 changes depending on the amount of the reflected light beam L _m ′.

The drive amount calculation unit 103 converts the sent movement amount into a drive amount for each stage of the shift stage 32 and sends it to the measurement control unit 100.
The measurement control unit 100 sequentially displays the light intensity acquired from the photodiode 12 on the display unit 15 through the data acquisition unit 101.
On the other hand, when the movement amount is input from the operation input unit 14, the measurement control unit 100 sends the drive amount sent from the drive amount calculation unit 103 to the movement control unit 102 to drive the shift stage 32.

The operator confirms the light intensity displayed on the display unit 15, performs an operation input from the operation input unit 14, appropriately moves the measurement optical unit 30 along the measurement optical axis P, and displays it for each movement position. The light intensity displayed on the unit 15 is compared to find a position where the light intensity is maximum. As a result, as shown in FIG. 4A, the intersection S of the measurement optical axis P and the lens surface 10a to be tested coincides with the focal position F of the condenser lens 8 (hereinafter referred to as “focus position adjustment state”). Can be called).
However, in this focus position adjustment state, the measurement optical axis P is not necessarily perpendicularly incident on the lens surface 10a to be examined.

Next, the incident angle of the measurement optical axis P is adjusted. This adjustment is also performed only by parallel movement by the shift stage 32.
The operator performs an operation input from the operation input unit 14, moves the measurement optical unit 30 in a direction orthogonal to the measurement optical axis P, and forms a focus position adjustment state at each movement position in the same manner as described above. .
The operator searches for a position where the light intensity displayed on the display unit 15 in this focus position adjustment state becomes larger than the intensity in the abduction position adjustment state before the movement, and this is determined as the measurement optical axis P. The position on the surface 10a to be examined where the light intensity is maximum is searched for by repeating in the biaxial direction orthogonal to.
As a result, as shown in FIG. 4B, the measurement optical unit 30 is aligned at a position where the measurement optical axis P is perpendicularly incident on the lens surface 10a (incidence angle 0 °).
The state in which the focal position F of the condenser lens 8 coincides with the test lens surface 10a and the measurement optical axis P is perpendicularly incident on the test lens surface 10a is hereinafter referred to as a “normal incidence adjustment state”. .
In the vertical incidence adjustment state, and the tilting center Q of the goniostage 33, and the center of curvature O _a of the lens 10, both located on the measurement optical axis P.

Next, by performing the tilting of the measurement optical axis P, it performs the adjustment operation of aligning the measurement optical axis P to the lens optical axis O _0.
In order to align the measurement optical axis P with the lens optical axis O ₀ from the normal incidence adjustment state shown in FIG. 4B, it is necessary to tilt the measurement optical axis P to match the inclination angle of the lens optical axis O _0. There is. In the present embodiment, since the tilt of the measurement optical axis P is performed around the tilt center Q of the gonio stage 33, as shown in FIG. 4C, only the tilt includes the vertical incident adjustment state and the focus position adjustment state. Will collapse at the same time.
In the present embodiment, as described below, when the operator sets the rotation angle θ, when the measurement optical unit 30 is tilted by the angle θ by the goniostage 33, the measurement optical unit 30 is brought into the normal incidence adjustment state. The control unit 13 calculates the amount of parallel movement of the measurement optical unit 30 for placement.

When the operator inputs the rotation angle θ from the operation input unit 14 in the normal incidence adjustment state, the measurement control unit 100 drives the optical path length changing unit 16 to measure the measurement light beam L _m having the first surface 20a as a reflection surface. from the optical path length shorter optical path length than, the sample lens rear surface 10b to the longer optical path length than the optical path length of the measurement beam L _m of a reflective surface and changes the optical path length of the reference light beam L _r.
Then, the measurement control unit 100 acquires the output of the photodiode 12 accompanying the change in the optical path length from the data acquisition unit 101 and sends the measurement data to the separation distance calculation unit 105. At this time, the measurement data acquired from the data acquisition unit 101 is as shown in the graph of FIG.
The separation distance calculation unit 105 calculates the peak value and the position where the separation occurs from the measurement data, calculates the separation distance c from the positions d ₁ and d ₂ , and calculates the peak values I _a and I _b at the positions d ₃ and d ₄ . Calculate and send to the measurement control unit 100.

The measurement control unit 100 displays the peak values I _a and I _b as _a graph on the display screen 15 a of the display unit 15 and sends the separation distance c and the rotation angle θ to the drive amount calculation unit 103.
The drive amount calculation unit 103 calculates the drive amounts of the shift stage 32 and the gonio stage 33 for rotating the measurement optical unit 30 in the normal incidence adjustment state by θ around the center of curvature O _a , and the measurement control unit To 100.
For example, to shift from the normal incidence adjustment state shown in FIG. 4B to the normal incidence adjustment state shown in FIG. 6B, the gonio stage 33 as shown in FIG. From the state, the parallel movement of δ by the shift stage 32 as shown in FIG.
In the vertical incidence adjustment state, as shown in FIG. 4 (b), the distance between the centers r _Q from tilting center Q to the center of curvature O _a is the distance T from the tilting center Q to the focal position F, the test lens surface the sum of the radius of curvature _{R a} of 10a.
As can be seen from FIG. 2, the distance T is the sum of the separation distance c measured in the normal incidence adjustment state and the distance b between the second surface 20b and the tilting center Q. r _Q is represented by the following equation (1).

r _Q = R _a + c + b (1)

Here, the separation distance c is a measurement value sent from the measurement control unit 100, and the curvature radius _Ra and the distance b are known shared parameters.
First, when the angle θ is tilted by the gonio stage 33, the measurement optical axis P ₀ (see FIG. 4B) in the normal incidence adjustment state is changed to the measurement optical axis P ′ as shown in FIG. 4C. Move to the position. The coordinates of the rotational position of the point O _a ′ on the measurement optical axis P ′ corresponding to the center of curvature O _a in the normal incidence adjustment state are calculated from the angle θ and the center-to-center distance r _Q.
To move from this state to the state of FIG. 6 (b), as shown in FIG. 6 (a), the inclination angle of the measurement optical axis P ′ is kept constant (the position of the gonio stage 33 is fixed), The distance O should be translated so that the point O _a ′ coincides with the center of curvature O _a . At this time, the measurement optical axis P ′ moves to the position of the measurement optical axis P ″. By this parallel movement, the tilting center Q in FIG. 4C is translated by a distance δ to the position of the point Q ″ in FIG.

Therefore, the drive amount calculation unit 103 obtains a parallel movement vector from the coordinate value of the point O _a ′ and the coordinate value of the center of curvature O _a , and drives this vector converted into the movement amount of each axis of the shift stage 32. The amount is calculated and sent to the measurement control unit 100.
The measurement control unit 100 displays this drive amount on the display unit 15.
The operator inputs the drive amount displayed on the display unit 15 from the operation input unit 14 and drives the gonio stage 33 and the shift stage 32. Thereby, the normal incidence adjustment state shown in FIG. 6B is realized.
In the above description, the parallel movement is described after the tilting, but this is for explaining the calculation principle of the movement amount. If the driving amount is calculated, the actual driving order of the shift stage 32 and the gonio stage 33 may be reversed or may be driven in parallel.

In this way, the operator can change the angle of the measurement optical axis P with respect to the lens optical axis O ₀ while maintaining the normal incidence adjustment state by simply inputting the rotation angle θ.
When such movement is repeated, the peak values I _a and I _b of the light intensity are displayed on the display unit 15 for each movement position.
Here, in each vertical incidence adjustment state, the measuring beam L _m is perpendicularly incident on the target lens surface 10a, the peak value I _a is constant except for measurement errors due to reflection variations in a reflective surface. On the other hand, since the incident angle of the measurement optical axis P with respect to the lens back surface 10b changes, the peak value _Ib changes.
Therefore, the operator repeats the rotational movement of the measurement optical axis P as described above in the biaxial direction perpendicular to the measurement optical axis P until the peak value _Ib reaches the maximum.
Thus, when the peak value I _b is maximized, the measurement optical axis P, as shown in FIG. 6 (c), that are aligned with the center of curvature O _a, lens optical axis O ₀ through O _b Become.
Thus, the adjustment operation is completed to align the measurement optical axis P to the lens optical axis O _0.

The operator performs an operation input notifying that the adjustment operation has been completed. Thereby, the measurement control part 100 starts the measurement of a surface interval.
That is, the measurement data of the light intensity at the final adjustment position is acquired through the data acquisition unit 101 and sent to the surface interval calculation unit 104.
For example, as shown in FIG. 7, the measurement data at this time is such that the peak values I _a and I _b are the maximum values I _a0 and I _b0 , and the difference between the positions d ₃ and d ₄ is the surface of the lens to be examined. This coincides with the optical path length n · d corresponding to the surface distance d between 10a and the rear surface 10b of the lens to be examined. Here, n is the refractive index of the glass material of the lens 10 to be examined, and is a shared parameter stored in the measurement control unit 100 in advance.
Therefore, the surface interval calculation unit 104 analyzes the peak position of the measurement data, calculates the surface interval d by dividing the difference between the positions d ₃ and d ₄ by the refractive index n, and sends it to the measurement control unit 100.
The measurement control unit 100 displays the measured surface distance d.
This completes the measurement of the surface spacing.

Thus, according to the lens surface interval measuring device 50 of the present embodiment, by condensing the measuring beam L _m is irradiated to the test lens 10 condenses the reflected light beam L _{m 'from} the test lens 10 The measurement optical unit 30 is movably supported on the support unit 31 and includes the separation distance measurement unit 34 and the drive amount calculation unit 103, so that the measurement optical unit 30 is centered on the curvature of the lens surface 10a of the test lens 10. It can be easily rotated around O _a . Therefore, with respect to the test lens 10, by adjusting the measurement optical unit 30 to the positional relationship of the normal incidence adjustment state, by keeping this vertical incidence adjustment state, it can be easily rotated around the center of curvature O _a .
As a result, it is possible to quickly find the state in which the measurement optical axis P and the lens optical axis O ₀ are aligned. Therefore, the measurement optical axis P can be easily positioned with respect to the lens 10 to be measured disposed outside the apparatus. Thus, the distance between the lens surfaces of the test lens 10 can be measured.
Therefore, for example, even when the test lens 10 is attached to the polishing dish 19 in the polishing process, the distance between the lens surfaces can be measured without removing it from the polishing dish 19. For this reason, the finished state of polishing can be accurately measured. Further, when the polishing amount is insufficient, the rework can be continued immediately from the same state as the work stop state.

  In the present embodiment, the separation distance measurement unit 34 includes the parallel plate 20, the separation distance calculation unit 105, and the measurement control unit 100. Similarly to the measurement of the surface separation, the separation distance is measured using low coherence interference. Can be calculated. For this reason, since a part of the separation distance measurement unit 34 is also used as a surface interval measurement unit, the configuration is simple and the measurement optical unit 30 can be downsized.

[First Modification]
Next, a first modification of the first embodiment will be described.
As illustrated in FIGS. 1 and 3, the lens surface distance measuring device 50 </ b> A of the present modification includes a control unit 13 </ b> A instead of the control unit 13 of the first embodiment.
The control unit 13A includes a measurement control unit 100A instead of the measurement control unit 100 of the control unit 13 of the first embodiment.
Hereinafter, a description will be given centering on differences from the first embodiment.

In the measurement control unit 100A, when the normal incidence adjustment state is formed and then the rotational movement of the measurement optical axis P is performed, the shift stage 32 and the gonio stage 33 are moved based on the drive amount sent from the drive amount calculation unit 103. It differs from the first embodiment in that the driving control is performed and the state automatically shifts to the normal incidence adjustment state shown in FIG.
For this reason, in this modification, the operation input auxiliary unit 107 of the first embodiment is not configured.

  According to this modification, since the operator does not need to re-input the driving amount, the workability of the operator is improved and the optical axis alignment can be adjusted more quickly.

[Second Embodiment]
Next, a second embodiment of the present invention will be described.
FIG. 8 is a schematic configuration diagram showing the configuration of the main part of the lens surface distance measuring device according to the second embodiment of the present invention. FIG. 9 is a functional block diagram showing a functional configuration of a control unit used in the lens surface distance measuring device according to the second embodiment of the present invention.

The lens surface distance measuring device 50B according to the present embodiment is obtained by realizing the separation distance measuring unit 34 according to the first embodiment with a different configuration. As shown in FIGS. The separation distance calculation unit 105 is deleted, and instead of the parallel plate 20 and the measurement control unit 100, a laser length measuring device 21 (non-contact length measuring device), a movable holding unit 22, and a measurement control unit 100B are provided. Here, the laser length measuring machine 21 and the movable holding unit 22 constitute a separation distance measuring unit 34 of the present embodiment.
Hereinafter, a description will be given centering on differences from the first embodiment.

The laser length measuring machine 21 measures the distance between the measurement optical unit 30 and the lens surface 10a to be tested, and the movable lens 22 and the lens to be tested are moved by the movable holding unit 22 fixed to the housing 30b. 10 is held so as to be able to advance and retreat on the optical path between the two.
The movable holding unit 22 may employ an appropriate moving mechanism that rotates or slides the laser length measuring device 21.
When the laser length measuring machine 21 is advanced onto the optical path between the condenser lens 8 and the test lens 10 by the movable holding portion 22 (see the two-dot chain line in FIG. 8), the laser length measuring machine 21 performs length measurement. The measurement reference axis is advanced to a position aligned with the measurement optical axis P.
In the present embodiment, as shown in FIG. 8, at the advance position of the laser length measuring device 21, the length measurement reference position 21a extends from the tilt center Q along the measurement optical axis P in the same manner as in the first embodiment. It is arranged at the position of distance b.
As shown in FIG. 9, the separation distance measuring unit 34 of the present embodiment, which includes the laser length measuring device 21 and the movable holding unit 22, is connected to the measurement control unit 100B of the control unit 13B so as to be communicable.

Measurement control unit 100B performs a tilting of the measuring optical axis P, measured optical axis P when performing an adjustment operation of aligning the lens optical axis O _0, using a laser length measuring machine 21 and the movable holding portion 22 Only the point of obtaining the separation distance c is different from the first embodiment.
That is, the measurement control unit 100B drives the movable holding unit 22 to advance the laser length measuring device 21 on the measurement optical axis P, and the laser light for measurement from the laser length measuring device 21 to the lens surface 10a to be measured. The distance c between the length measurement reference position 21a of the laser length measuring device 21 and the lens surface 10a to be measured is measured.
When the measurement of the distance c is completed, the measurement control unit 100B drives the movable holding portion 22 is retracted from the optical path along the laser length measuring machine 21 to the measuring optical axis P, the measurement light beam L _m is the test lens 10 Make it ready for irradiation.
Then, using the separation distance c acquired from the laser length measuring device 21, operation control similar to that in the first embodiment is performed.

The present embodiment is different from the first embodiment only in that the separation distance measuring unit 34 is composed of the laser length measuring device 21 and the movable holding unit 22. Can be measured.
According to this embodiment, since it is not necessary to place the parallel flat plate 20 in the optical path of the measurement beam L _m, the light amount loss of the measuring beam L _m is reduced. Thereby, compared with the said 1st Embodiment, the low output light source 1 is employable.

  In the description of each of the embodiments and the first modification, the example in which the tilt center Q is set on the measurement optical axis P has been described. However, this is an example, and the position of the tilt center Q is described. May be at a position different from the measurement optical axis P.

  In the description of each of the above embodiments and the first modification, the example in which the support unit uses a magnet stand has been described. However, this is an example, and the measurement optical unit is located in the vicinity of the lens 10 to be measured. If it can support stably, the structure of a support part will not be specifically limited.

  In the description of the second embodiment, the length measuring device used in the separation distance measuring unit described in the example in which the laser length measuring device 21 is provided as the separation distance measuring unit is a non-contact length measuring device. What is necessary is not limited to the laser length measuring device.

  Moreover, all the components described in the above embodiments can be implemented by appropriately changing or deleting the combination within the scope of the technical idea of the present invention.

1 Light source 2 Fiber coupler (light beam splitting unit, beam combining unit)
2a, 2b, 2c, 2d Fiber coupler end face 3, 7 Collimating lens 4 Linear motion stage 5 Reference mirror 6 Linear scale 8, 11 Condensing lens 10 Test lens 10a Test lens surface (lens surface)
10b Back surface of the lens to be examined (lens surface)
12 Photodiodes 13, 13A, 13B Control unit 14 Operation input unit 15 Display unit 16 Optical path length changing unit 17 Photodetecting unit 20 Parallel flat plate (reference optical element)
20a 1st surface 20b 2nd surface 21 Laser length measuring machine (non-contact length measuring machine)
22 Movable holding part 30 Measurement optical part 30a Measurement optical system 31 Support part 32 Shift stage (parallel movement mechanism)
33 Goniometer stage (tilting mechanism)
34 Separation distance measurement unit 50, 50A, 50B Lens surface interval measurement device 100, 100A, 100B Measurement control unit 102 Movement control unit 103 Drive amount calculation unit 104 Surface interval calculation unit 105 Separation distance calculation unit 107 Operation input auxiliary unit c Separation distance F focal position Lr reference light flux P measurement optical axis _{O a} center of curvature _{O b} curvature center _{O 0} lens optical axis P, P ', P''measurement optical axis Q, Q', Q '' tilting center _{r Q} center distance

Claims (6)

A light source;
A light beam splitting unit that converts a light beam from the light source into a measurement light beam and a reference light beam;
An optical path length changing unit for changing an optical path length of the reference light beam;
A measurement optical unit that condenses the measurement light beam and irradiates the lens to be examined, and condenses the reflected light beam from the lens;
A light beam combining unit that forms a combined light beam by superimposing the reflected light beam from the test lens and the reference light beam;
A light detector that collects the combined luminous flux and detects the light intensity of the combined luminous flux;
A support unit that supports the position and orientation of the measurement optical unit in an adjustable manner by having a translation mechanism that translates the measurement optical unit and a tilting mechanism that tilts the measurement optical unit;
An operation input unit capable of operation input for moving the measurement optical unit;
A movement control unit that controls the movement of the measurement optical unit by driving the parallel movement mechanism and the tilting mechanism based on the operation input;
A separation distance measurement unit that measures a separation distance on the optical axis of the measurement optical unit between the measurement optical unit and the lens surface of the test lens;
Calculating a center-to-center distance between the tilt center of the measurement optical unit and the center of curvature of the lens surface based on the separation distance, and rotating the measurement optical unit around the center of curvature of the lens surface; A drive amount calculation unit for calculating drive amounts of the parallel movement mechanism and the tilt mechanism;
A lens surface distance measuring device comprising: When the rotation angle for rotating the measurement optical unit around the center of curvature of the lens surface or the shortest movement length on the lens surface is input to the operation input unit, the drive amount calculation unit 2. An operation input auxiliary unit that calculates drive amounts of the parallel movement mechanism and the tilt mechanism corresponding to the rotation angle or the shortest movement length and displays the drive amount is provided. Lens surface distance measuring device. The separation distance measurement unit includes:
A reference optical element disposed at a fixed position on the optical path of the measurement light beam in the measurement optical unit;
When the optical path length of the reference light beam is changed by the optical path length changing unit, by detecting a change in light intensity due to interference between the optical surface of the reference optical element and the lens surface of the lens to be tested, 3. The lens surface distance measuring device according to claim 1, wherein a distance is calculated. The beam splitting unit and the beam combining unit are
The lens surface distance measuring device according to claim 1, comprising a fiber coupler connected to the light source, the optical path length changing unit, and the measuring optical unit. The movement control unit
When the rotation angle or the rotational movement distance on the lens surface for rotating the measurement optical unit around the center of curvature of the lens surface is input to the operation input unit, the drive amount calculation unit The amount of drive of the translation mechanism and the tilt mechanism corresponding to the rotation angle or the rotation movement distance is calculated,
The lens surface distance measuring device according to claim 1, wherein the parallel movement mechanism and the tilting mechanism are driven based on the driving amount. The separation distance measurement unit includes:
The lens surface distance measuring device according to claim 1, comprising a non-contact length measuring device provided in the measuring optical unit.

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