JP2002005621A - Method and apparatus for measuring eccentricity of lens array die - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a method and an apparatus for measuring and evaluating relative positional shift (eccentricity) of individual lens faces, formed on a plural ity of dowels for forming a lens array molding die. SOLUTION: When eccentricity of a die is measured by detecting relative positional shift between the centers of curvature of adjacent lens faces from the detection results of the center of curvature of each lens face 5 of a lens array molding die, eccentricity is measured sequentially for respective lens faces 5, while moving the die along the arranging direction of lens faces. The centers of curvature are measured simultaneously as a set for two or more adjacent lens faces 5 at each measuring position of the die, such that one or more common center of curvature of lens face 5 is present in continuous sets. The positions of the center of curvature of all lens faces 5 are then associated by comparing the detection results in each set of lens faces 5 common to continuous sets, thus removing measurement errors caused by positional variation of an objective lens face 5 from having affecting on the measurement of eccentricity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring the eccentricity of a lens array mold, which is a method for measuring the eccentricity of a lens surface of a lens array molding mold, and a lens array mold eccentricity measuring apparatus used for the method.

[0002]

2. Description of the Related Art In a writing optical system such as a laser printer, an imaging optical element (lens array) in which lenses are linearly arranged is sometimes used. Lens arrays are often made by molding plastic.

A mold used for molding a lens array is formed by attaching a metal piece having a mirror-finished lens surface to be transferred to a lens to be molded to a mold frame. The gold pieces are precision processed by cutting and grinding so that the lens surfaces are arranged in a straight line.

A tool for processing such a gold piece gradually wears as the lens surface is sequentially processed, so that the processing conditions for each lens surface change. Therefore, when the lens array is long in the lens arrangement direction, that is, when the number of lenses is large, the difference in processing conditions between the lens surface processed at the beginning and the lens surface processed at the rear increases. As a result, there may be a large difference in the accuracy of the lens surface between both ends of the gold piece.

In order to prevent such inconvenience, a gold piece for forming one lens array is divided into several pieces in the lens arrangement direction and processed into a plurality of blocks, and these blocks are placed in a mold frame. In this case, a method of forming a mold by sequentially arranging the dies is adopted. As an example of forming a lens array molding die in this way, there is a technique described in JP-A-11-77763.

[0006]

When the metal pieces formed in a divided state are arranged in a mold frame, if the lens surfaces are not aligned substantially in a straight line and at substantially equal intervals in the arrangement direction,
Since the individual lens imaging positions of the lens array to be formed are shifted, desired optical performance cannot be obtained.

In order to position the lens surface at a desired position, first, it is necessary to detect the position of the lens surface.

According to the present invention, the relative position deviation (eccentricity) of individual lens surfaces formed on a plurality of metal pieces forming a lens array molding die, or the absolute position of individual lens surfaces with respect to an arbitrarily set reference. It is an object to obtain a method and an apparatus for measuring and evaluating a displacement.

[0009]

According to a first aspect of the present invention, there is provided a lens array mold eccentricity measuring method, wherein the lens array molding mold for molding a lens array in which a plurality of lenses are linearly connected is provided. For each of the lens surfaces transferred to the lens, if this lens surface is spherical, the center of curvature is detected, and if the lens surface is aspheric, the paraxial center of curvature is detected, and from the detection result, In a lens array mold eccentricity measuring method for measuring the eccentricity of the lens array forming mold by detecting a relative positional deviation between a center of curvature or a paraxial curvature center of the adjacent lens surfaces,
The lens array molding die is moved along the arrangement direction of the lens surfaces to sequentially shift the lens surface to be measured to the adjacent lens surface, and each of the lens array molding dies is moved. For each measurement position, the center of curvature or the center of paraxial curvature of two or more adjacent lens surfaces is simultaneously detected as a set, and the center of curvature of one or more common lens surfaces or the near center of curvature is continuously detected in the set. By presenting an axial center of curvature, and comparing the detection results in each of the sets of the lens surfaces that are common to the successive sets, associating the positions of the centers of curvature or paraxial centers of curvature of all the lens surfaces, The influence of the measurement error due to the variation in the position of the lens surface to be measured on the eccentricity measurement is eliminated.

Therefore, it is possible to eliminate the influence of the error of the position taken by each lens surface at the measurement position on the eccentricity measurement of the lens surface.

According to a second aspect of the present invention, there is provided a lens array mold eccentricity measuring method, wherein the lens is transferred to the lens provided in a lens array molding mold for molding a lens array in which a plurality of lenses are linearly connected. For each of the faces,
If the lens surface is spherical, the center of curvature is detected. If the lens surface is aspherical, the paraxial center of curvature is detected. From the detection result, the center of curvature of each lens surface with respect to a predetermined position is determined. Alternatively, in the lens array mold eccentricity measuring method for measuring the eccentricity of the lens array molding die by detecting an absolute displacement of a paraxial center of curvature, the lens array molding metal may be arranged along an arrangement direction of the lens surface. The lens surface to be measured is moved sequentially by moving the mold to the adjacent lens surface, and for each measurement position of the lens array molding die, two or more adjacent lens surfaces are measured. The center of curvature or the paraxial center of curvature is simultaneously detected as a set, and in the continuous group, the center of curvature or the center of paraxial curvature of one or more common lens surfaces is present, and the continuous center is set. By comparing the detection results in each of the sets of the lens surfaces that are common to each other, the positions of the centers of curvature or the centers of paraxial curvatures of all the lens surfaces are associated with each other, and the dispersion of the positions of the lens surfaces to be measured is determined. Eliminate the effect of the resulting measurement error on the eccentricity measurement.

Therefore, it is possible to eliminate the influence of the error of the position taken by each lens surface at the measurement position on the eccentricity measurement of the lens surface.

According to a third aspect of the present invention, there is provided a lens array mold eccentricity measuring apparatus, wherein a lens array molding mold for molding a lens array in which a plurality of lenses are linearly connected is formed by a lens array molding mold. Moving means for movably supporting the lens surface to be transferred to the lens along the arrangement direction of the lens surface, position detection means for detecting the position of the lens array molding die in the arrangement direction of the lens surface, and the lens For each surface, an optical system unit that detects the center of curvature of the lens surface that is a spherical surface or the paraxial center of curvature of the lens surface that is an aspheric surface, and is adjacent to each measurement position of the lens array molding die. Simultaneous detection means for simultaneously detecting the center of curvature or the paraxial curvature center of the two or more lens surfaces as a set, and the continuous set detected by the simultaneous detection means. Overlapping measurement means for controlling the moving means such that there is one or more common centers of curvature or paraxial centers of curvature of the lens surfaces, and detection in each set of the lens surfaces common to successive sets. By comparing the results, the positions of the centers of curvature or paraxial centers of curvature of all the lens surfaces are associated with each other, and the influence of the measurement error due to the variation of the positions of the lens surfaces to be measured on the eccentricity measurement is removed. Error correction means.

Therefore, the influence of the movement error of the moving means on the eccentricity measurement of the lens surface can be eliminated.

According to a fourth aspect of the present invention, in the lens array eccentricity measuring apparatus according to the third aspect, the optical system unit includes a light source for irradiating the lens surface with light and a reflection from the lens surface. An optical system for imaging light at a predetermined position, and a light receiving element for receiving the reflected light imaged at the predetermined position are provided.

Therefore, the configuration described in claim 3 can be realized.

According to a fifth aspect of the present invention, in the lens array eccentricity measuring apparatus according to the fourth aspect, the optical path of the reflected light is changed so that the reflected light from the lens surface forms an image at a predetermined position. Light guiding means for causing the light to flow.

Therefore, even if the distance between adjacent lens surfaces is inappropriate, reflected light can be focused on a predetermined position.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to a lens array molding die, which is capable of adjusting the relative position deviation (hereinafter referred to as "eccentricity") of each lens surface formed on a metal piece, or an individual reference to an arbitrarily set reference. Measuring the absolute displacement of the lens surface of
The present invention relates to a method and an apparatus for evaluating.

In order to determine the eccentricity, the position of the center of curvature (or the paraxial center of curvature) of each lens surface is detected while moving the lens array molding die in the direction of arrangement of the lens surfaces, and their relative positions are detected. As a basic measurement principle, a method of detecting a position shift or an absolute position shift of each lens surface with respect to an arbitrarily set reference is used.

In the following embodiment, for the sake of simplicity, the case where the lens surface is spherical will be described, and the center of curvature will be detected to evaluate the displacement. Is an aspherical surface, its paraxial center of curvature is detected to evaluate the displacement. In that case, in the following embodiment, “center of curvature” is “paraxial center of curvature”.
Is replaced by

FIG. 1 shows a first embodiment of the present invention.
This will be described with reference to FIG. First, an example of the configuration of the lens array molding die 1 will be described with reference to FIG.

A lens array molding die (hereinafter, simply referred to as “die”) 1 has a die frame 2, and a groove 3 is formed in the center of the die frame 2. A plurality of gold pieces 4 are arranged in the groove 3.

The gold piece 4 has a lens surface 5 to be transferred to a lens provided in the lens array. Lens surface 5
Is concave and mirror-finished. Each gold piece 4 is formed with two lens surfaces 5. In the present embodiment, the total number of the gold pieces 4 is eight, each of which is fitted into the groove 3 and fixed with a bolt (not shown).

FIG. 2 is a front view showing a schematic configuration of a lens array mold eccentricity measuring device (hereinafter, simply referred to as a “measuring device”) 10. In FIG. 2, the mold 1 is shown in a longitudinal section along the direction in which the lens surfaces 5 are arranged.

The measuring apparatus 10 firstly includes the optical system unit 1
1, the optical system unit 11 includes a light source 12,
A beam splitter 13, a lens 14 as an optical system,
15 and a CCD camera 16 having a light receiving element.

The CCD camera 16 and the lenses 14 and 15 are arranged in a straight line in this order.
These optical axes A coincide. The light source 12 is disposed such that the optical axis B of the laser beam emitted by the light source 12 is orthogonal to the optical axis A.

The intersection of the optical axis A and the optical axis B is located between the CCD camera 16 and the lens 14, and the beam splitter 13 is disposed at this position. The beam splitter 13 forms 45 ° with both the optical axis A and the optical axis B.

The optical path length between the light source 12 and the lens 14 is adjusted in advance so that the light traveling between the lens 14 and the lens 15 becomes substantially parallel light. Further, the position of the optical system unit 11 is adjusted such that the focal point p of the light converged by the lens 15 substantially coincides with the center of curvature q of the lens surface 5.

The optical system unit 11 is mounted on a stage (not shown) which advances and retreats in a direction parallel to the optical axis A (the direction of the arrow in FIG. 2), and is used for attaching and detaching the mold 1 to and from the measuring apparatus 10. , Can be evacuated. Further, with such a structure, the position of the focal point p and the center of curvature q can be easily adjusted when the type of the mold 1 to be measured is changed.

The position of the CCD camera 16 is adjusted so that its image pickup surface is located near the focal point r of the lens 14.

An image input device 17 is connected to the CCD camera 16, and the image input device 17 is connected to a personal computer (hereinafter, referred to as a personal computer) 18. The personal computer 18 has a monitor 19. C
Data of an image captured by the CD camera 16 is input to a personal computer 18 via an image input device 17 and
9 is displayed.

The mold 1 has a moving mechanism 20 as moving means.
Is mounted on the stage 21 provided in the. The moving mechanism 20
The stage 2 is moved so that the mold 1 moves in the direction in which the lens surfaces 5 are arranged by the driving force of the stepping motor 22.
Move 1

The stepping motor 22 includes a driver 23
The pulse controller 24 is connected to the personal computer 18 via a pulse controller 24, and receives a pulse output from the pulse controller 24 via a driver 23 in response to a request from the personal computer 18 to rotate.

The stepping motor 22 is provided with a rotation origin position sensor (not shown) as position detection means. By counting the number of pulses, the position and the movement amount of the stage 21 with respect to the arrangement direction of the lens surface 5 are determined. You can know.

By attaching a detector such as a laser scale to the stage 21, the stage 2 can be more accurately adjusted.
It is also possible to acquire the position information of No. 1 and perform positioning.

In the above configuration and arrangement, the position of the center of curvature q of the lens surface 5 can be detected as the position of the reflected spot image from the lens surface 5 on the imaging surface of the CCD camera 16 by using the auto-collimation method. .

The image of the reflected spot from the lens surface 5 captured by the CCD camera 16 is displayed on a monitor 19 of a personal computer 18 via an image input device 17, and at the same time,
The coordinates (Xc, Yc) of the position of the center of gravity is calculated by the following equation (1).
Is calculated.

[0039]

(Equation 1)

Here, the X direction is the direction orthogonal to the lens arrangement, and the Y direction is
The direction is defined as a lens arrangement direction. In the equation (1), n is the number of effective data in the calculation of the center of gravity of the spot.

First, the barycentric coordinates (Xcj, Ycj) of the reflected spot image from any lens surface 5 are stored. Next, the stage 21 is moved substantially by the pitch of the lens surface 5 to obtain the barycentric coordinates (Xcj + 1, Ycj + 1) of the reflected spot image from the adjacent lens surface 5.

Using these barycentric coordinates, the displacement amount D of the center of curvature q of the adjacent lens surface 5 is calculated by the following equation (2).
It is calculated by the formula.

[0043]

(Equation 2)

Here, f1 in the following equation (2) is
5 is the focal length, f2 is the focal length of the lens 14, a is the CCD
This is the size of one pixel of the camera.

Also, for example, with reference to the position of the rightmost lens surface 5 of the mold 1 in FIG. 2, the coordinates of the reflected spot image are set to (Xc0, Yc0), and the stage 21 is pitched to the lens surface 5. Each time, the absolute displacement of each lens surface 5 with respect to the reference lens surface 5 is obtained by calculating the displacement D of the center of curvature q of the lens surface 5 by the following equation (3). Can be requested.
In implementation, an optimal reference may be set according to the usage of the lens array.

[0046]

(Equation 3)

FIG. 3 shows a conceptual diagram of a measurement result based on a reflection spot image from the rightmost lens surface 5. Here, D1 to D7 are measured positional deviation amounts of the center of curvature q of the lens surface 5.

When the eccentricity of the lens surface of the mold 1 is measured by the apparatus shown in FIG. 2, the stage 21 is moved along the arrangement direction of the lens surface 5 of the mold 1 as described above.
The stage 21 has a movement error. Common items include straightness errors in the horizontal and vertical directions, angular errors in pitching, yawing, and rolling. Positioning errors in the moving direction.

Due to these movement errors, the stage 2
The center of curvature q of the lens surface 5 of the mold 1 mounted on the mold 1 is displaced, which appears as an eccentricity measurement error.

In the present embodiment, when detecting the position of the center of curvature q of each lens surface 5 while moving the mold 1 along the arrangement direction of the lens surfaces 5, two or more adjacent lens surfaces 5 are used. 5, the position of the center of curvature q is simultaneously detected. Then, at least one or more common lens surfaces 5 are set between the set of the centers of curvature q observed before moving the mold 1 and the set of the centers of curvature q observed after moving the mold 1. There is a center of curvature q. This eliminates the influence of the movement error of the stage 21 on the eccentricity measurement.

Here, in order to remove the influence of the straightness error among the movement errors of the stage 21, the positions of the centers of curvature q of two adjacent lens surfaces 5 are simultaneously detected, and the mold 1 is moved.
One or more common lens surfaces between the set of the centers of curvature q of the lens surfaces 5 detected before moving the mold 1 and the set of the centers of curvature q of the lens surfaces 5 detected after the mold 1 is moved. It suffices that there are five centers of curvature q.

In order to remove the angle error among the movement errors of the stage 21, the positions of the centers of curvature q of three or more adjacent lens surfaces 5 are simultaneously detected, and before the mold 1 is moved. A set of the detected centers of curvature q of the lens surfaces 5;
Between the set of the centers of curvature q of the lens surfaces 5 detected after moving the mold 1, it is necessary that q or more of the centers of curvature of the two or more common lens surfaces 5 exist (in this regard, the second This will be described in an embodiment.).

In this embodiment, a case where the influence of the straightness error is removed will be described with reference to FIGS. Here, an example using the auto-collimation method is shown.

FIG. 4 shows the optical system unit 11 in the measuring apparatus 10 shown in FIG. First, the condensing position p of the convergent light by the lens 15 is determined by the center of curvature q of the lens surfaces 5a and 5b.
The optical system unit 11 is set so as to substantially coincide with the center of a and qb.
Are determined in the directions of the optical axes A and B and the position of the mold 1.

Then, the two adjacent lens surfaces 5a, 5a
b, light is reflected from each of them, and respective centers of curvature q
The reflected spot images qa 'and qb' of a and qb are observed on the imaging surface of the CCD camera 16. However, the aperture (not shown) of the illumination optical system is determined so that light is illuminated on two adjacent lens surfaces 5a and 5b. Here, the simultaneous detection means is realized.

FIG. 5 shows a state in which a reflected spot image at the center of curvature q obtained on the imaging surface of the CCD camera 16 is monitored.

(A) shows a state before movement of the stage 21. The reflected spot images qa 'and qb' at the centers of curvature qa and qb are shown.
Have been observed.

(B) shows the state after the movement of the stage 21. The reflection spot image qa 'disappears, and the reflection spot image qb' of the lens surface 5b and the curvature center qc of the lens surface 5c adjacent to the lens surface 5b are removed. The reflection spot image qc 'is observed. Here, an overlapping measuring means is realized.

As the reference axis O, for example, an axis is set such that the centers of curvature q of all the lens surfaces 5 are individually observed in advance and the average of the distances to each center of curvature q is minimized. It is assumed that the position of the mold 1 mounted on the stage 21 has been adjusted so that the reference axis O is substantially parallel to the movement axis of the stage 21.

First, before the movement of the stage 21, the reflected spot images qa 'and qb' of the centers of curvature qa and qb are observed at the same time, so that the straightness error of the stage 21 does not affect their positional relationship.

From this state, the stage 21 is moved,
When observing the reflection spot images qb 'and qc' of the curvature centers qb and qc, if there is a straightness error in the stage, the positions of the curvature centers qb and qc are shifted by the error Sb. qc ′ is qb ″ and qc ″, respectively.
Are observed, and db ′ and dc ′ are obtained as positional deviation amounts with respect to the reference axis O, respectively.

However, the reference axis O of the center of curvature qb '
Is known, the straightness error Sb is obtained by taking the difference between db and db '. Therefore, by subtracting Sb from dc ', a correct distance dc is obtained.

Thus, one or more common centers of curvature q
While observing (in the above example, qb is common), by detecting the positional relationship between the two curvature centers q, the stage 2 is detected.
The eccentricity measurement can be performed without the influence of the straightness error among the one movement error. Here, an error correcting means is realized.

Here, in this example, the centers of curvature q of all the lens surfaces 5 are individually observed in advance, and the axis that minimizes the average of the distance to each center of curvature q is set as the reference axis O. Therefore, although the straightness error component of the stage 21 is included in the reference axis O, the distances of the positions of the centers of curvature q of all the lens surfaces 5 with respect to the reference axis O are known. An axis that minimizes the average of the distances to q may be set as the correct reference axis O1, and the distances of the centers of curvature q of all the lens surfaces 5 to the correct reference axis O1 may be calculated.

Further, in order to simultaneously determine the positions of the two centers of curvature q with the measuring device 10 of FIG. 2, it is necessary to calculate the respective barycentric positions of the two reflected spot images observed in the field of view of the CCD camera 16. In that case, for example, C
By dividing the field of view of the CD camera 16 into two regions for calculation, and calculating the expression (1) in each region,
The position of the center of gravity of the two reflected spot images can be obtained.

Further, since the above example is complicated,
The description has been made assuming that there is no positioning error in the moving direction, that is, the Y component in equations (2) and (3) is zero. By using the equation, the influence of the positioning error can be considered.

In this case, the straightness error obtained from the positional relationship between the reflection spot images q 'of the two adjacent centers of curvature q is subtracted from the X component in the equations (2) and (3), and the movement obtained in the same manner. The positioning error in the direction is subtracted from the Y component in equations (2) and (3).

As a result, the influence of the straightness error of the stage 21 and the positioning error in the moving direction on the eccentricity measurement can be eliminated.

Next, a second embodiment of the present invention will be described with reference to FIGS. Note that the same reference numerals are used for the same portions as those described in the previous embodiment, and detailed description of those portions is omitted (the same applies to the following embodiments).

In the first embodiment, since there is only one common center of curvature q at each measurement position of the mold 1, angle information cannot be obtained. The effects of errors cannot be eliminated.

Therefore, in the present embodiment, in order to eliminate the angular error, three or more centers of curvature q are simultaneously observed at each measurement position, and the measurement is performed such that the common center of curvature q becomes two or more. Choose a position. By knowing the positional relationship between the two centers of curvature q in this way, information on the angular displacement before and after the movement of the stage 21 can be obtained, so that not only the effect of the straightness error of the stage 21 but also the effect of the angular error Can be removed. This will be described below with reference to FIGS.

The optical system unit 11 shown in FIG. 6 has the same configuration as that of the optical system unit 11 shown in FIG.
b, the optical system unit 1
The position of the mold 1 in the directions of the optical axes A and B and the position of the mold 1 are adjusted.

As a result, the three adjacent lens surfaces 5a
5c are reflected, and the images qa 'to qc' of the respective centers of curvature qa to qc are observed on the imaging surface of the CCD camera 16. However, an opening (not shown) of the illumination optical system is determined so that light is illuminated on three adjacent lens surfaces 5a and 5b.

FIG. 7 shows a state in which a reflected spot image at the center of curvature q obtained on the imaging surface of the CCD camera 16 is monitored.

(A) shows the state before movement of the stage 21, and the reflected spot images qa 'to qc' at the centers of curvature qa to qc.
Have been observed.

(B) shows the state after the movement of the stage 21. The reflected spot image qa 'disappears, the reflected spot image qb' on the lens surface 5b, the reflected spot image qc 'on the lens surface 5c, and the lens surface 5c. And a reflection spot image qd 'of the center of curvature qd of the adjacent lens surface 5d are observed.

First, before the stage 21 is moved, the inclination θa of a straight line passing through qa ′ and qb ′ with respect to an arbitrarily set reference axis O and qb ′ with respect to the reference axis O are determined from the position of each curvature center q. And the inclination θb of a straight line passing through qc ′.

When the stage 21 is moved from that state by the pitch of the lens surface 5 of the mold 1, qb 'and qc'
Is commonly observed before and after the movement, so that the positional relationship is maintained.

If there is an angle error in the movement error of the stage 21, the inclination of a straight line passing through qb 'and qc', which should be calculated as θb, with respect to the reference axis O is calculated as θb '. Will be. However, since the value of θb is known, the angle error included in the movement error of the stage 21 can be detected by calculating the difference between θb and θb ′.

Therefore, by correcting the position of the center of curvature q in consideration of the detected movement error of the stage 21, the influence of the movement error of the stage 21 on the eccentricity measurement can be eliminated.

As described above, the positions of the centers of curvature q of three or more lens surfaces 5 adjacent to the mold 1 are simultaneously detected, and the positions of two or more common centers of curvature q before and after the movement of the stage 21 are detected. By observing, the angle error included in the movement error of the stage 21 can be detected, and the influence of the angle error on the eccentricity measurement can be removed.

Incidentally, the setting method of the reference axis O includes, for example,
There is the method described in the first embodiment.

In this embodiment, the straightness error and the positioning error with respect to the moving direction have been described as having no influence. However, even if they are detected, detection is performed by the method described in the first embodiment. Thus, the influence of the angle error, the influence of the straightness error, and the influence of the positioning error on the moving direction can be eliminated at the same time.

Next, a third embodiment of the present invention will be described with reference to FIG.

In the second embodiment, when the lens surface 5 of the mold 1 is illuminated with light to form an image of the reflected light and the position of the reflected image is detected by the light receiving element, the optical system unit 11 is used.
With respect to the above characteristic, if the distance between adjacent lens surfaces is sufficiently small, reflected images from a plurality of lens surfaces 5 can be received by a single light receiving element. However, if the distance between the adjacent lens surfaces 5 is too large with respect to the characteristics of the optical system unit 11, the distance between the reflected images becomes too large, and a single light receiving element cannot reflect the reflected images from the plurality of lens surfaces 5. Light cannot be received.

Even if the distance between the lens surfaces 5 is small, it becomes difficult to form reflected images from a plurality of lens surfaces 5 on a single light receiving element if the imaging magnification of the optical system is increased. .

Although such inconvenience can be dealt with by providing a plurality of light receiving elements, the cost is increased accordingly.

Furthermore, if the interval between the reflected images is too wide to receive light with a single light receiving element, but too narrow to arrange and receive light from a plurality of light receiving elements, the light receiving elements may collide with each other. It is possible that it will.

The present embodiment aims to solve such a problem. Optical system unit 31 shown in FIG.
Corresponds to the optical system unit 11 shown in FIGS.
The configuration is such that mirrors 32 and 33 as light guide means are added. The mirrors 32 and 33 are disposed on both sides of the imaging surface of the CCD camera 16 so as to be line-symmetrically opposed to the optical axis A. More specifically, mirrors 32 and 33
The light reflected from the lens surfaces 5c and 5a is reflected to form a CCD.
On the imaging surface of the camera 16 so that each reflected light forms an image,
Their position and angle have been adjusted.

The reference for the positional relationship of a plurality of images to be observed simultaneously can be arbitrarily adjusted by adjusting the mirrors 32 and 33. For example, the mirror can be adjusted by using a reference prototype processed sufficiently smaller than the required accuracy of the eccentricity measurement. The positions and angles of 32 and 33 may be adjusted.

Usually, a problem with the eccentricity of the lens surface 5 is the alignment of the metal pieces 4 with respect to the mold frame 2, and eccentricity occurs between the adjacent lens surfaces 5 formed on the adjacent metal pieces 4. For the lens surfaces 5 on the same gold piece 4, the processing accuracy of the gold piece 4 is generally sufficiently smaller than the required accuracy of eccentricity. The position and the angle of the mirrors 32 and 33 may be adjusted by using it as a container.

Further, means for adjusting the positioning of these mirrors 32 and 33 and means for adjusting the angles may be added to the mirrors 32 and 33 to improve the operability in the adjustment and the eccentricity reference calibration work. Good.

[0093]

According to the first and second aspects of the present invention, it is possible to eliminate the influence on the eccentricity measurement of the lens surface due to the error of the position taken by each lens surface at the measurement position, thereby realizing a highly accurate eccentricity measurement. can do.

According to the third aspect of the present invention, it is possible to eliminate the influence of the movement error of the moving means on the eccentricity measurement of the lens surface, so that highly accurate eccentricity measurement can be realized.

According to the invention described in claim 4, the configuration described in claim 3 can be realized.

According to the fifth aspect of the invention, in the fourth aspect of the invention, even if the distance between adjacent lens surfaces is inappropriate, reflected light can be imaged at a predetermined position.
The eccentricity of various lens array molding dies having different lens surface intervals can be measured.

[Brief description of the drawings]

FIG. 1A is a plan view showing a structure of a lens array molding die for molding a lens array, and FIG. 1B is a right side view thereof.

FIG. 2 is a front view showing a schematic configuration of a lens array mold eccentricity measuring apparatus according to the first embodiment of the present invention.

FIG. 3 is a conceptual diagram of a measurement result based on a reflection spot image from a rightmost lens surface.

FIG. 4 is a front view showing an optical system unit and an optical path.

FIG. 5 is an explanatory diagram showing a state in which a reflection spot image at the center of curvature obtained on the imaging surface of the light receiving element is monitored;
(A) shows the state before the movement, and (b) shows the state after the movement.

FIG. 6 is a front view showing an optical system unit and an optical path according to a second embodiment of the present invention.

FIG. 7 is an explanatory diagram showing a state in which a reflected spot image at the center of curvature obtained on the imaging surface of the light receiving element is monitored;
(A) shows the state before the movement, and (b) shows the state after the movement.

FIG. 8 is a front view showing an optical system unit and an optical path according to a third embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 lens array molding die 5 lens surface 10 lens array die eccentricity measuring device 11 optical system unit 12 light source 14, 15 optical system 20

Claims (5)

[Claims] 1. A lens array forming die for forming a lens array in which a plurality of lenses are arranged in a straight line, wherein each lens surface transferred to the lens is provided.
If the lens surface is spherical, the center of curvature is detected.If the lens surface is aspheric, the paraxial center of curvature is detected.From the detection result, the center of curvature or paraxial of the adjacent lens surface is detected. In a lens array mold eccentricity measuring method for measuring the eccentricity of the lens array molding die by detecting a relative positional deviation between the centers of curvature, the lens array molding die is arranged along the arrangement direction of the lens surfaces. The lens surface to be measured is moved so as to sequentially transition to the adjacent lens surface, and for each measurement position of the lens array molding die, the curvature centers of two or more adjacent lens surfaces are measured. Alternatively, the paraxial center of curvature is simultaneously detected as one set, and in the successive sets, the center of curvature or the paraxial center of curvature of one or more common lens surfaces exists, and the common By comparing the detection results of each set of the lens surfaces, the positions of the centers of curvature or paraxial curvature centers of all the lens surfaces are associated with each other,
A lens array mold eccentricity measuring method, wherein an influence of a measurement error due to a variation in the position of the lens surface to be measured on the eccentricity measurement is removed. 2. A lens array forming die for forming a lens array in which a plurality of lenses are arranged in a straight line, wherein each lens surface transferred to said lens is provided.
If the lens surface is spherical, the center of curvature is detected. If the lens surface is aspherical, the paraxial center of curvature is detected. From the detection result, the center of curvature of each lens surface with respect to a predetermined position is determined. Alternatively, in a lens array mold eccentricity measuring method for measuring the eccentricity of the lens array molding die by detecting an absolute displacement of a paraxial curvature center, the lens array molding metal may be arranged along an array direction of the lens surface. The lens surface to be measured is moved sequentially by moving the mold to the adjacent lens surface, and for each measurement position of the lens array molding die, two or more adjacent lens surfaces are measured. The center of curvature or the center of paraxial curvature is simultaneously detected as one set, and the center of curvature or the center of paraxial curvature of one or more common lens surfaces is present in the continuous set, and before the continuation. By comparing the detection result of each said set of said lens surfaces is common in pairs, in association with the position of the center of curvature or paraxial curvature center of all of the lens surfaces,
A lens array mold eccentricity measuring method, wherein an influence of a measurement error due to a variation in the position of the lens surface to be measured on the eccentricity measurement is removed. 3. A lens array molding die for molding a lens array in which a plurality of lenses are arranged in a straight line, along a direction in which lens surfaces are transferred to the lenses provided in the lens array molding die. Moving means for movably supporting the lens array; position detecting means for detecting a position of the lens array molding die in the arrangement direction of the lens surfaces; and for each of the lens surfaces, a center of curvature of the spherical lens surface. Or an optical system unit that detects a paraxial center of curvature of the lens surface that is an aspheric surface, and for each measurement position of the lens array molding die, a curvature center or paraxial of two or more adjacent lens surfaces. Simultaneous detection means for simultaneously detecting the center of curvature as a set, and a continuous set detected by the simultaneous detection means,
Overlapping measuring means for controlling the moving means such that there is one or more common centers of curvature or paraxial centers of curvature of the lens surfaces; and detection in each set of the lens surfaces common to successive sets. By comparing the results, the positions of the centers of curvature or paraxial centers of curvature of all the lens surfaces are associated with each other,
Error correction means for removing the influence on the eccentricity measurement of the measurement error due to the variation of the position of the lens surface of the measurement object,
A lens array mold eccentricity measuring device comprising: 4. An optical system unit comprising: a light source for irradiating the lens surface with light; an optical system for imaging reflected light from the lens surface at a predetermined position; and the reflected light imaged at the predetermined position. The lens array eccentricity measuring apparatus according to claim 3, further comprising: a light receiving element that receives light. 5. The lens array eccentricity measuring apparatus according to claim 4, further comprising light guiding means for changing an optical path of the reflected light so that the reflected light from the lens surface forms an image at a predetermined position.