JP2002254479A - Eccentricity measuring instrument for lens mirror surface piece in mold for molding optical image forming element, and eccentricity measuring method using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a measuring instrument for measuring and evaluating positional shift of a lens mirror surface piece in a mold for molding an optical image forming element and to measure and evaluate the positional shift of the lens mirror surface piece in the mold for molding the optical image forming element with high accuracy using the measuring instrument. SOLUTION: The instrument for measuring and evaluating the positional shift of the lens mirror surface piece is equipped with an optical system for detecting the center-of-curvature position of the adjacent lens mirror surface pieces, a mold position detection means, the position adjusting means of an optical system, the focus adjusting means of the optical system and a means for operating the eccentricity of the lens mirror surface piece on the basis of the center-of-curvature position of the lens mirror surface piece and the position of the mold. The positional shift of the lens mirror surface piece is measured and evaluated with high accuracy by adapting various error correction method, using this instrument.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for measuring the eccentricity of a mirror piece for a lens in a mold for molding a plastic optical imaging element such as a lens or a mirror prism.

[0002]

2. Description of the Related Art FIG. 7 is a perspective view for explaining an example of an optical imaging device. In FIG. 7, 1, 1 _n and 1 _{n + 1} are incident-side lenses, and 2, 2 _n and 2 _{n + 1} are images. The side lens, 3 is a roof prism, and X is an arrangement direction. In the example shown in FIG. 7, the incident-side lens 1 and the imaging-side lens 2 are
A roof prism lens including a roof prism 3 having a ridge line formed by a plane having an appropriate degree is an optical imaging element arranged in an array in the X direction.

FIG. 8 shows an example in which the positions of the n-th entrance lens _1n and the imaging lens _2n are shifted from the (n + 1) th entrance lens _{1n + 1} and the imaging lens _{2n + 1.} And the position shift a of the incident side lens and the position shift b of the image formation side lens are combined to generate the position shift c of the image formation position.

The example shown in FIG. 9 shows the deviation c of the image formation position due to the prism tilt (angle θ2). The image-side optical axis tilts (angle θ) due to the prism tilt (angle θ2).
1) Due to this, the shift c of the imaging position occurs.

[0005]

As described above, in each of the roof prism lenses of the optical imaging elements arranged in an array, if the lens position or the prism angle shift occurs, the n-th and n + 1-th are set. Because the imaging position of
The combination causes an image shift, which has an adverse effect on optical characteristics (reduction in resolution).

More specifically, since the displacement of each element by several μm and several seconds adversely affects the optical characteristics, a method of manufacturing a plastic lens optical element having a plurality of lenses and prisms requires a lens or prism to be assembled into a mold. One of the issues is to assemble a mirror piece corresponding to the above with high precision. Along with this, a measurement technique for evaluating the accuracy of assembly is required.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an optical imaging element molding die for forming a high-quality optical imaging element.
It is an object of the present invention to provide an apparatus and a method for measuring the positional shift of a lens mirror piece which causes the above-mentioned lens positional shift. Since the displacement of the lens mirror piece has the same meaning as the displacement of the center of curvature of the lens mirror piece, in the following description, the above-described displacement of the lens mirror piece will be expressed by the term eccentricity. Also, if the lens mirror piece is an aspherical surface, the eccentricity of the positional deviation of the paraxial curvature center,
It will be treated in the same way as the center of curvature on a spherical surface.

More specifically, according to the first aspect of the present invention, as a device for measuring and evaluating the positional shift of a lens mirror piece in a mold for molding an optical imaging element, a test die is provided with an optical axis. An object of the present invention is to provide a measuring apparatus having an optical system for simultaneously observing the center positions of curvatures of two or more adjacent lens surfaces of a lens to be inspected in order to correct the effect of a movement error caused by the movement of the means for moving in the direction. And

In the technique according to the first aspect, the lens array mold is moved in the direction in which the lens array molds are arranged using the stage, but the moving means includes motion errors such as straightness error, pitching, and yawing. The center of curvature of the lens surface is misaligned, and the misalignment results in an eccentricity measurement error.
The measurement accuracy of the device deteriorates. A moving means such as an air slider which has a small motion error may be used. However, when the required eccentricity accuracy of the optical element to be formed becomes extremely high, or when the optical element becomes long (long in the arrangement direction), the movement may occur. If a long moving stroke of the means is required, the moving means such as an air slider becomes very expensive.

Therefore, in the invention according to claim 2,
2. The technique according to claim 1, further comprising: a plurality of lenses to be used in a scanning shape measurement and a roundness measurement based on an output from an optical system for simultaneously observing the center positions of curvatures of two or more adjacent lens mirror surfaces. To provide a measurement method capable of realizing high eccentricity measurement accuracy without using expensive moving means by correcting the effect of movement error of the moving means on eccentricity measurement by applying a point method algorithm. With the goal. For details of the above multipoint method, refer to the description of Tomoaki Kishi and Kenji Konosu, "Generalization of Shape Measurement by Multipoint Method" (Journal of the Japan Society of Precision Engineering, Vol.60, No.3, 1994). it can.

When the above-mentioned multipoint method is applied to a scanning type shape measuring device or the like, two or more displacement meters are installed in the measuring device,
A multipoint method operation is performed based on these outputs to determine the shape of the test surface. In this case, if the distance between the installed displacement meters is different from the set one, the error becomes an error in the multi-point method calculation, and becomes a measurement error of the apparatus. On the other hand, in the present invention, instead of detecting the displacement, the center of curvature of the mirror piece of the lens to be detected is detected.
An optical system capable of simultaneously detecting the center positions of the curvatures of two or more lens mirror pieces is used.

In this case, the distance between the displacement gauges in the scanning type shape measurement corresponds to the distance between the centers of curvature of adjacent lens mirror pieces, which is affected by the pitch error (array eccentricity) of the object to be measured. Therefore, the curvature center interval is definitely different from the set value at all, and varies. Therefore, the displacement meter interval error in the scanning shape measurement occurs as a variation error in the measurement in the eccentricity measurement, and becomes an analysis error in the multipoint method calculation. Therefore, claim 3
An object of the present invention is to correct such an error and improve the analysis accuracy and the measurement accuracy of the device.

When eccentricity measurement is performed using the above-described technique, first, the test die is set on the moving means of the test die, and the center image of the curvature of the lens mirror piece of the test die is measured by the optical system. The position of the test die or the optical system must be adjusted so that observation is possible. However, the size of the light-receiving element used in the optical system is limited, and the higher the resolution of the eccentricity measurement (the higher the magnification of the optical system), the more the center image of the lens mirror piece curvature in the initial state is optically converted. The task of finding in the system becomes difficult. For this reason, it may take a very long time to find the center image of curvature of the lens surface piece to be inspected. Therefore, an object of the invention according to claim 4 is to solve such a problem, to shorten the measurement time and improve the operability of the apparatus.

When the eccentricity measurement is performed using the above-described technique, first, the test die is set on the moving means of the test die, and the center image of the curvature of the lens mirror piece of the test die is measured by the optical system. The optics must be adjusted so that the system can observe them. In this case, since the center image of curvature is blurred just by installing the test die, it is necessary to adjust the focus so that an optimum image without blur is obtained. Therefore, claim 5
The object of the invention according to the present invention is to automatically perform such adjustment and improve the operability of the device.

When the position or focus of the optical system is adjusted by the method according to the fourth or fifth aspect, the center image of the curvature of the mirror piece of the lens to be inspected must be observed with an appropriate brightness by the optical system. If the image is too bright, extra light will be picked up by the optical system, making it impossible to know where the original center-curvature image is. If the image is too dark, the image cannot be detected. Therefore, an object of the present invention is to improve the operability of the apparatus by automatically adjusting the brightness of an image.

[0016]

Means for Solving the Problems In order to achieve the above objects, the present invention adopts the following constitution. In other words, the eccentricity measuring device for the lens mirror piece in the optical imaging element molding die according to claim 1 is an entrance side lens located on the entrance side, and is formed optically equivalent to the entrance side lens, and An imaging lens having an optical axis orthogonal to the optical axis of the incident lens and located on the imaging side;
A roof prism having a ridgeline disposed so as not to be orthogonal to any of the optical axes of the incident and imaging lenses in a plane formed by the optical axes of these lenses between the incident and imaging lenses. An optical imaging element forming mold for forming an optical imaging element, comprising: an entrance-side lens mirror piece for forming the incident-side lens; and an imaging-side lens mirror piece. For the image element molding die,
In the apparatus for measuring the eccentricity of a lens mirror piece in an optical imaging element molding die for measuring a relative position shift of an adjacent lens mirror piece or an absolute position of each lens mirror piece with respect to an arbitrarily set reference, An optical system for simultaneously detecting the center of curvature of two or more lens mirror pieces adjacent to the mirror piece for imaging, and simultaneously detecting the center of curvature of two or more lens mirror pieces adjacent to the mirror piece for imaging side lens. Optical system, means for moving the mold in a direction in which the lens forming surface is arranged, means for detecting the position of the mold moving means in the arrangement direction, and an optical system for the entrance-side lens mirror piece For moving the lens moving means in the direction substantially perpendicular to the moving direction of the mold moving means, and an optical system position adjusting means for the incident side lens mirror piece, and for the image forming side lens mirror piece. An imaging-side lens mirror piece optical system position adjusting means for moving the optical system in a direction substantially perpendicular to the direction of movement of the mold moving means; and An optical system focus adjusting means for the incident-side lens mirror piece for moving in the optical axis direction, and an image-forming lens mirror surface for moving the optical system for the image-forming lens mirror piece substantially in the optical axis direction of the lens mirror piece. Frame optical system focus adjustment means, means for setting the attitude of the mold in the direction of movement in the arrangement direction, the center of curvature of the mirror piece for the entrance side lens, the center of curvature of the mirror piece for the imaging side lens, and Means for calculating the eccentricity based on the position of the mold moving means in the arrangement direction.

According to the apparatus for measuring the eccentricity of a lens mirror piece in an optical imaging element molding die according to the present invention, an apparatus for measuring and evaluating the displacement of a lens mirror piece in an optical imaging element molding die. Can be realized.

According to a second aspect of the present invention, there is provided a method for measuring the eccentricity of a lens mirror piece in an optical imaging element molding die according to the first aspect. The method is characterized in that an error given to the eccentricity measurement due to a movement error due to the movement of the mold moving means is corrected by using a multipoint algorithm.

According to the method of measuring the eccentricity of the mirror piece for the lens in the mold for molding an optical imaging element according to the present invention, the effect of the movement error of the moving means on the eccentricity measurement is corrected without using expensive moving means. In addition, high eccentricity measurement accuracy can be realized.

According to a third aspect of the present invention, there is provided a method for measuring the eccentricity of a lens mirror piece in an optical imaging element molding die according to the first aspect of the present invention. When using, the error in the multipoint method arithmetic processing caused by the spacing error of the center of curvature of the lens mirror piece detected by the optical system for the lens mirror piece on the entrance side and the imaging side, the distance between the center of curvature of the lens mirror piece The correction is performed using the error measurement value.

According to the method for measuring the eccentricity of the mirror piece for the lens in the optical imaging element molding die according to the present invention, it is possible to correct the analysis error in the multipoint method calculation and improve the measurement accuracy.

According to a fourth aspect of the present invention, there is provided a method for measuring the eccentricity of a mirror surface piece for a lens in a mold for molding an optical imaging element according to the first aspect. By using the incident-side lens mirror piece optical system, the incident-side lens mirror piece optical system position adjusting means is moved while observing the presence or absence of a reflected image signal from the lens mirror piece. While observing the presence or absence of a reflected image signal from the lens mirror piece by the image-side lens mirror piece optical system, moving the imaging-side lens mirror piece optical system position adjusting means, the incident-side and image-forming lens The position of the mirror piece optical system is adjusted so as to be optimal for performing the eccentricity measurement.

According to the method for measuring the eccentricity of the lens mirror piece in the mold for molding an optical imaging element according to the present invention, the operation for finding the center of curvature of the lens mirror piece to be inspected is automated, so that the measurement time can be reduced and the apparatus can be used. Operability can be improved.

According to a fifth aspect of the present invention, there is provided a method for measuring the eccentricity of a mirror surface piece for a lens in a mold for molding an optical imaging element according to the first aspect. When using, while observing the reflected image from the lens mirror piece by the incident-side lens mirror piece optical system, by moving the incident-side lens mirror piece optical system focus adjustment means, also, the imaging side lens While observing the reflected image from the lens mirror piece by the mirror piece optical system, by moving the focus adjusting means for the image forming side lens mirror piece, the optical system for the incident side and the image forming side lens mirror piece is moved. Optimum focus adjustment for performing eccentricity measurement is performed.

According to the method for measuring the eccentricity of a mirror surface piece for a lens in an optical imaging element molding die according to the present invention, the operability of the apparatus is improved by automating focus adjustment for obtaining an optimal image without blurring. Can be achieved.

According to the fifth aspect of the present invention, there is provided a method for measuring the eccentricity of a mirror surface piece for a lens in a mold for molding an optical imaging element according to the first aspect. In addition to the above, in addition to the configuration, a light intensity adjusting means of the reflected image from the incident side and the imaging side lens mirror piece is used, and the reflected image from the lens mirror piece by the optical system for the incident side and the imaging side lens mirror piece. While observing the eccentricity, the light intensity of the reflected image is adjusted optimally for performing the eccentricity measurement.

According to the method for measuring the eccentricity of the mirror piece for the lens in the mold for molding an optical imaging element according to the present invention, the operability of the apparatus can be improved by automatically adjusting the brightness of the image. .

[0028]

Embodiments of the present invention will be described below in detail with reference to preferred embodiments shown in the drawings.

FIG. 1 is a perspective view for explaining an example of a mirror piece of an optical element mold and a mold base to which the present invention is applied. In FIG. A mirror surface portion, 5 is a mirror surface piece for the imaging side lens, 5a is a mirror surface portion, and 6 is a mold frame.

The mold frame 6 has a groove formed at the center thereof.
The mirror piece 4 for the lens on the incident side and the mirror piece 5 for the imaging lens are fitted into grooves formed in the mold frame 6 so as to face each other, and are inserted into the mold frame 6 by bolts (not shown). It is fixed to. As described above, the mirror surface piece fixed to the mold frame 6 needs to be installed so that the lens surfaces are arranged substantially linearly in the arrangement direction and at substantially equal intervals.

Here, each of the above-mentioned mirror surface pieces is mounted on the mold frame 6 one by one. The eccentricity measuring device for the lens mirror piece in the optical imaging element injection molding die according to the present invention is as described above. It is intended to be used for detecting the position of the lens surface in the mounting adjustment of the mirror surface piece, or for evaluating the eccentricity after the mirror surface piece is completely mounted on the mold frame 6.

In the following description, array eccentricity and orthogonal eccentricity will be described. Here, eccentricity in the array direction such as pitch error and spacing error of the lens mirror piece is referred to as array eccentricity. The eccentricity with respect to the direction orthogonal to the arrangement direction, such as the displacement and the alignment error, is referred to as orthogonal eccentricity.

FIG. 2 is a perspective view of an essential part of a mold for injection molding of an optical imaging element and an eccentricity measuring method according to an embodiment of the present invention. In FIG. 2, reference numeral 7 denotes a center-of-curvature detecting unit for the mirror piece for the incident-side lens, 8 denotes a center-curvature detecting unit for the mirror piece for the imaging-side lens, and 9 denotes a jig for setting the attitude of the mold during measurement. , 1
Reference numeral 0 denotes a feed stage that moves the mold in the direction in which the lens mirror pieces are arranged.

An optical system based on the principle of auto-collimation is built in both the curvature center position detection units 7 and 8, and the optical axis of the lens mirror piece (the axis connecting the vertex of the lens surface and the center of curvature) is 45. The optical axis of the detection optical system is inclined 45 degrees in accordance with the inclination. Since the optical axes of the lens mirror pieces on the incident side and the image forming side are orthogonal to each other, the optical axes of the corresponding curvature center position detecting optical systems are also orthogonal to each other.

In the apparatus shown in FIG.
Is moved in the lens mirror piece arrangement direction to detect the center of curvature of each lens mirror piece while feeding the mold. Here, the feeding of the mold is a step feeding corresponding to the distance between the centers of curvature of adjacent lens mirror pieces. FIG. 3 is a diagram for explaining an example of the internal configuration of the curvature center position detection unit, and constitutes an optical system based on the principle of autocollimation.

In FIG. 3, light substantially parallel to the optical axis of the optical system emitted from the laser light source 11 is radiated by the lenses 12 and 14 to the lens mirror piece 15 as parallel light. Light reflected from three adjacent surfaces (15a, 15b, 15c) of the lens mirror piece 15 is converted into parallel light by a lens 14, and is turned back by a beam splitter 13 and a mirror 16, and The light is condensed on an imaging surface of a CCD camera 18 as a light receiving element.

The focal point of the lens 14 is
center of curvature 15a ', 15b', 1 of a, 15b, 15c
5c '. The imaging surface of the CCD camera 18 is installed at a position substantially at the focal point of the lens 17,
The center images of curvature of the three lens mirror pieces are obtained on the CCD surface. The feed stage 10 is driven by a stepping motor (not shown), and the stepping motor rotates by receiving a pulse from a pulse controller (not shown).

The above-mentioned stepping motor is provided with a rotation origin position sensor (not shown). By counting the number of pulses, the position and the movement amount of the stage with respect to the lens mirror frame arrangement direction can be known. it can. In addition, by attaching a position detector such as a laser scale to the stage 10, the position information of the stage can be obtained and positioned with higher accuracy.

As a measurement procedure, first, the mold is placed on the stage 1
After setting to 0, the position of the mold with respect to the moving axis of the feed stage 22 is adjusted by using the displacement meters 19 and 20 as the mold position adjusting means and the position adjusting jig 21 as shown in FIG. . Specifically, the displacement of the side surface of the mold in the vertical and horizontal directions is detected by the displacement meters 19 and 20, and the stage 22 is moved until the displacement output accompanying the stage movement becomes substantially zero. The tilt and inclination of 21 are adjusted to adjust the position of the mold.

After the posture adjustment is completed, the feed stage is moved to arbitrarily select the center image of the curvature of the three lens mirror surface pieces on the CCD.
It is adjusted so that it can be observed on the camera imaging surface, and the position of each center of gravity is stored as coordinates of the CCD pixel. From this state, the mold feeding stage is moved by an amount corresponding to the distance between the centers of curvature of adjacent lens mirror pieces (design value of the optical imaging element), and the center of gravity of three adjacent lens mirror piece curvature center images is shifted. Detect and store the barycentric coordinates. The above operation is repeated by the number of surfaces of the lens mirror surface piece to be inspected, and the center of gravity coordinate data of the curvature center image three times the number of lens mirror surface surfaces is recorded.

The barycentric coordinates of the three centers of curvature image observed by the above-described _{CCD, p i {x (u} ), y (u)} (i = 1,
2, 3). Based on the lens pitch of the lens array and the magnification of the optical system, the reference coordinates Ci (xc,
If yc) is set in advance, the deviation Pi {x (u), y (u)} from the reference position of the center of curvature of the lens is expressed by the following equation (1).
become that way. Here, u is the number of the surface to be inspected, and m is the magnification of the optical system.

[0042]

(Equation 1)

Assuming that the lens pitch is q, of the three x-coordinate outputs and three y-coordinate outputs of Pi, P2 is located at a position q away in the arrangement direction with respect to the output of P1, P3 is located at a position 2q away, Each will be arranged. When these are replaced with displacement meter outputs in the multipoint method, the following equation (2) is obtained.
become that way.

[0044]

(Equation 2)

In the above equation (2), n is the total number of lens surfaces, q
Is a lens pitch, vx is an array eccentricity, vy is an orthogonal eccentricity, s is a stage shift error, and t is a stage tilt error. Assuming that weights applied to the respective outputs are w1, w2, and w3, the weighted addition T and the transfer function Hk are represented by the following equations (3) and (4).

[0046]

(Equation 3)

(Equation 4)

By executing the processing of FIG. 5 using the above, the array eccentricity vx (u) (x coordinate output) and the orthogonal eccentricity vy (u) of the lens array which are not affected by the stage shift error and the tilt error. ) (Y-coordinate output).

That is, after outputting the coordinates (step 31) according to the equations (1) and (2), the equations (3) and (4) are output.
Using the weighted addition T and the transfer function Hk obtained by
The calculations in steps 32 to 35 are performed, and the results are used. In step 36, the array eccentricity vx (u) (x coordinate output) and the orthogonal eccentricity of the lens array which are not affected by the stage shift error and the tilt error. vy (u) (y coordinate output) is obtained.

In the above process, the center of curvature of the lens mirror piece is detected with the spherical lens mirror piece as the object to be measured. However, when the object to be detected is the aspheric lens mirror piece, the paraxial curvature of the lens mirror piece is measured. What is necessary is just to detect the center position and perform the eccentricity measurement similarly to the above processing. In the following description, a spherical lens mirror piece will be described as an object to be measured. However, the same applies to an aspheric lens mirror piece, except that the paraxial curvature center position is detected instead of the curvature center. .

According to the above embodiment, it is possible to realize an apparatus for measuring and evaluating the displacement of a mirror surface piece for a lens in a mold for molding an optical imaging element, and furthermore, the effect of the movement error of the moving means on the eccentricity measurement. Is corrected and high eccentricity measurement accuracy can be obtained without using expensive moving means.

[Third Embodiment] In the multipoint method according to the first and second embodiments, when applied to a scanning type shape measuring device, two or more displacement meters are installed in the measuring device. Then, a multipoint method operation is performed based on those outputs to determine the shape of the surface to be inspected. In this case, if the distance between the installed displacement meters is different from the set one, the error becomes an error in the multi-point method calculation, and becomes a measurement error of the apparatus.

Therefore, in this embodiment, instead of detecting the displacement, the center of curvature of the lens mirror piece to be detected is detected. Therefore, the center of curvature of two or more adjacent lens mirror pieces is simultaneously measured instead of installing a displacement meter. Use a detectable optical system. In this case, the displacement meter interval in the scanning shape measurement is
This corresponds to the distance between the centers of curvature of adjacent lens mirror pieces, which is affected by the pitch error (array eccentricity) of the measurement target.

Therefore, the curvature center interval is almost certainly different from the set value at all, and fluctuates. Therefore, the displacement meter interval error in the scanning shape measurement occurs as a variation error in the measurement in the eccentricity measurement, and becomes an analysis error in the multipoint method calculation. The present embodiment is intended to correct the influence of the fluctuation of the curvature center interval on the eccentricity measurement.

In the apparatus and method according to the first and second embodiments, the shift error and the tilt error of the stage are corrected. It is very effective for correction calculation. This is because, in the above equation (2), the tilt component is multiplied by the center interval of curvature (the pitch of the mirror piece on the lens to be inspected).

On the other hand, the stage error which affects the measured value of the array eccentricity has a large shift error component such as a stage feed error, and the stage tilt error has a small effect on the measured value of the array eccentricity. Therefore, an object to be corrected for the influence of the center-of-curvature variation is orthogonal eccentricity measurement, and the measured value of array eccentricity is used for that purpose.

The procedure is as follows. First, eccentricity data P _i {x (u), y (u)} corresponding to the number of surfaces to be inspected are obtained, a stage error correction operation is performed for array eccentricity operation, and a stage error correction operation is performed. Obtain an unaffected array eccentricity measurement Vx (u). In this case, both the shift and tilt components of the stage may be corrected. However, since the influence of the tilt component is small, only the shift component may be corrected.

Then, the orthogonal eccentricity data is converted by the following equation (5) using the array eccentricity measurement value.

(Equation 5)

According to the above embodiment, the orthogonal eccentricity is obtained by the method described in the first and second embodiments using the above data. As a result, there is an effect that the arrangement eccentricity and the orthogonal eccentricity can be obtained without being affected by the fluctuation of the center of curvature and the influence of the stage error is corrected.

[Embodiments according to Claims 4, 5, and 6] FIG.
FIG. 1 shows an example of an apparatus configuration according to the present invention. here,
Only the periphery of the measurement optical system for measuring the entrance-side lens mirror piece is shown, but the same applies to the imaging-side lens mirror piece measurement optical system. In FIG. 6, 23 is a measuring optical system, 24 is a member supporting the measuring optical system, 25 is a measuring optical system 23 and a member 24,
A stage for moving back and forth in the direction substantially perpendicular to the movement axis of the feed stage 27 of the mold 26, and a stage 28 for moving the measuring optical system substantially in the direction of the optical axis of the lens piece to be measured.

Stepping motors 29 and 30 are attached to the stages 25 and 28, respectively, and the members 24 and the measuring optical system 23 or only the measuring optical system 23 can be moved forward and backward with the rotation thereof. Stage 2
5 and 28 are respectively moved to a predetermined initial position in advance. First, an embodiment according to claim 4 will be described.

According to an embodiment of the present invention, after the test die 26 is set on the feed stage 27, the measuring optical system is positioned at such a position that the center image of the curvature of the mirror piece of the test lens can be observed almost at the center of the CCD camera. It relates to adjustment for moving the system. However, since the center image of curvature moves only in the Y-axis direction of the CCD due to the movement of the stage 25, the aforementioned CCD
The approximate center of the camera indicates the center of the CCD in the Y-axis direction.

As an adjustment procedure, first, the stage 25
The CCD image is taken in at the initial position, and the presence or absence of the image is checked at that position. The checking is performed, for example, by binarizing the captured CCD image with a predetermined threshold value, and then determining the presence or absence of the image based on whether or not there is an effective pixel. Here, it is easier to determine the presence or absence of an image if the external light in the measurement optical system is sufficiently shielded and the threshold value is set as low as possible.

If there is no image at that position, the stage 25 is moved forward or backward by a predetermined amount,
The image is captured and the presence or absence of the image is checked. By continuing this operation, an image can be found. Stage 25
Is preferably set to a position as close as possible to the test die feeding stage 27 or a position as far as possible so that the stage 25 can move in one direction.

When the initial position is set to a position close to the test die feeding stage 27, the stage 25 is gradually retracted,
Conversely, when the initial position is set to a far position, the stage 25 is gradually advanced. The feed amount is determined in advance so that the image is not overlooked in consideration of the magnification of the measuring optical system. When an image is found, the stage 25 is moved so that the center of gravity is substantially at the center of the CCD in the Y-axis direction.

In this case, three center images of curvature of adjacent mirror lens pieces to be inspected should be observed by the CCD.
In addition, since the focus adjustment and the image intensity adjustment described below have not been completed, a large image should be observed.
The stage 25 may be adjusted so as to be substantially at the center in the axial direction. The accurate adjustment is performed as described later after the focus adjustment and the image intensity adjustment are completed.

Next, an embodiment according to claim 5 will be described. When the operation of the embodiment according to claim 4 is completed, the CCD
Then, some image is observed. The present embodiment relates to adjustment for observing the image as a correct focused image. First, CC at the initial position
The D image is captured and the size of the image is checked. As a check method, as described above, for example, the image may be binarized at a predetermined threshold value, and the number of effective pixels thereafter may be counted.

After detecting the size of the image, the stage 28 is moved forward or backward. Then, the CCD image is captured at that position, and the size of the image is checked as described above. When detecting the center of curvature of the lens piece to be inspected as a point image,
The movement of the stage 28 and the check of the image size are repeated until the point image becomes the smallest. It is determined whether the smallest image is larger than the size of the image just examined (whether the number of effective pixels is larger).
Can be done with

If the size of the image just examined is larger than the size of the image examined immediately before, the immediately preceding image is the smallest image, and the position of the stage 28 at that time is the position of the best focus. As described above, three images should be observed, but the sum of the effective pixels constituting each of the three images may be regarded as the size of the image.

Next, an embodiment according to claim 6 will be described. The embodiment according to claim 6 relates to the adjustment of the intensity of light applied to the mirror surface piece of the lens to be inspected. As an adjustment method, when an output modulation type semiconductor laser is used as a light source, its output may be modulated. In the case of other light sources, the threshold value for binarization may be changed, or an ND filter capable of modulating the transmission intensity may be used.

Here, description will be made assuming that a method of modulating the output of the semiconductor laser is used. First, a CCD image is taken in with the semiconductor laser output set to an initial value. Then, after checking the size of the image as described in the embodiment according to claim 5, the output of the semiconductor laser is changed and the CCD image is captured. The size of the image before and after the output modulation is compared, and the output modulation of the semiconductor laser, the capture of the CCD image, and the check of the image size are repeated so that the image is minimized. The determination as to whether the image is the smallest may be made in the same manner as in the above-described embodiment.

The focus adjustment and the image intensity adjustment are performed alternately so that the smallest image can be obtained. When the smallest image is obtained, the stage 25 is moved so that the image is substantially at the center of the CCD with respect to the Y-axis direction of the CCD.
The image is made to be substantially at the center with respect to the X-axis direction of the CD.

To determine whether the image is at the center, the center coordinates of the CCD may be stored in advance, and the value may be compared with the barycentric coordinates of the detected image. In that case, as described above, three images should be observed in the CCD, but any one of the images may be located at the center of the CCD.

In order to detect the center of gravity of one of the three images, the images are arranged on the CCD at substantially equal distances (an error corresponding to the eccentricity of the array is provided). The area near the center of the CCD may be designated by the area, and the center of gravity detection processing of the image may be performed on the area.

Each of the above embodiments is merely an example of the present invention, and the present invention is not limited to these embodiments. Appropriate changes and modifications may be made without departing from the spirit of the present invention. It goes without saying that improvements may be made.

[0075]

As described above, according to the present invention, the following excellent effects can be obtained.

That is, according to the first aspect of the present invention, an apparatus for measuring and evaluating the displacement of a lens mirror piece in a mold for molding an optical imaging element can be realized. According to the second aspect of the present invention, the apparatus according to the first aspect of the present invention is effectively used to correct the effect of the movement error of the moving means on the eccentricity measurement, and to use an expensive moving means. It is possible to realize a method for measuring and evaluating the displacement of the lens mirror piece in the optical imaging element molding die, which can obtain high eccentricity measurement accuracy without any problem.

According to the third aspect of the present invention, it is possible to correct the analysis error in the multipoint method operation and to improve the measurement accuracy. According to the fourth aspect of the present invention, the mirror surface of the lens to be inspected. By automating the operation of finding the center image of the curvature of the piece, the measurement time can be reduced and the operability of the device can be improved. Further, according to the invention according to claim 5, by automating focus adjustment for obtaining an optimal image without blur,
The operability of the device can be improved. According to the invention of claim 6, the operability of the device can be improved by automatically adjusting the brightness of the image.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a mirror piece and a mold base of an optical element molding mold to which the present invention is applied.

FIG. 2 is a perspective view of a main part configuration for describing an embodiment of an optical imaging element injection molding die and an eccentricity measuring method thereof according to the present invention.

FIG. 3 is a diagram illustrating an example of an internal configuration of a curvature center position detecting unit in the eccentricity measuring device for an optical imaging element injection molding die according to the embodiment.

FIG. 4 is an explanatory view of a procedure for adjusting the attitude of the mold in the eccentricity measuring device for the mold for injection molding of an optical imaging element according to the embodiment.

FIG. 5 is a flow chart showing an open sea of an error correction process in the eccentricity measuring device for an optical imaging element injection molding die according to the embodiment.

FIG. 6 is a diagram showing a configuration around an optical system for measuring an incident side lens mirror surface piece of the eccentricity measuring device of the optical imaging element injection molding die according to the embodiment.

FIG. 7 is a perspective view illustrating an example of an optical imaging element.

FIG. 8 is a diagram for explaining a shift of an image forming position due to a lens position shift of the optical image forming element shown in FIG. 7;

FIG. 9 is a diagram for explaining a shift of an image forming position due to a fall of a prism of the optical image forming element shown in FIG. 7;

[Explanation of symbols]

1,1 _n , 1 _{n + 1} Incident lens on the side 2,2 _n , 2 _{n + 1} Image-side lens 3 Roof prism 4 Mirror piece for entrance lens 4a Mirror surface 5 Mirror piece for image-side lens 5a Mirror surface 6 Mold frame 7 Detector of the center of curvature of the mirror piece for the incident side lens 8 Detector of the center of curvature of the mirror piece for the imaging side lens 9, 21 Jig for setting the attitude of the mold at the time of measurement 10, 22 Feed stage 11 Laser light source 12, 14 , 17 Lens 13 Beam splitter 15 (15a, 15b, 15c) Lens mirror surface piece 16 Mirror 18 CCD camera 19, 20 Displacement meter 23 Measurement optical system 24 Measurement optical system support member 25 Measurement optical system and feed stage of its support member 26 Gold Mold 27 Die feed stage 28 Measurement optical system feed stage 29, 30 Stepping motor 31-36 Processing step

Claims (6)

[Claims] An incident side lens located on the incident side, and an optical axis formed optically equivalent to the incident side lens and orthogonal to the optical axis of the incident side lens, on the image forming side. The imaging-side lens is located between the incident-side and imaging-side lenses, and is disposed in a plane formed by the optical axes of these lenses so as not to be orthogonal to any of the optical axes of the incident-side and imaging-side lenses. A mold for forming an optical imaging element comprising a roof prism having an inclined ridge line, and a mirror piece for an incident side lens and an imaging side lens for forming the incident side lens. For the optical imaging element molding die having a mirror piece for the optical imaging element for measuring the relative position shift of the mirror piece for the adjacent lens or the absolute position of each mirror piece for the lens with respect to an arbitrarily set reference. For lenses in molds In the eccentricity measuring apparatus for a mirror piece, an optical system for simultaneously detecting the center of curvature of two or more lens mirror pieces adjacent to the mirror lens for the entrance side, and two or more adjacent mirror pieces for the imaging side lens. An optical system for simultaneously detecting the center of curvature of the lens mirror piece, means for moving the mold in the direction in which the lens forming surface is arranged, and means for detecting the position of the mold moving means in the arrangement direction. An incident-side lens mirror piece optical system position adjusting means for moving the optical system for the incident-side lens mirror piece in a direction substantially perpendicular to the moving direction of the mold moving means; and the image-forming lens mirror piece. An imaging-side lens mirror piece optical system position adjusting means for moving an optical system for use in a direction substantially perpendicular to the direction of movement of the mold moving means; and an optical system for the entrance lens mirror piece as a lens. An optical system focus adjustment means for the entrance-side lens mirror piece for moving the mirror piece substantially in the optical axis direction, and an image forming device for moving the optical system for the image-forming lens mirror piece almost in the optical axis direction of the lens mirror piece. An optical system focus adjustment means for the side lens mirror piece;
Means for setting the attitude of the mold with respect to movement in the arrangement direction, the center of curvature of the entrance-side lens mirror piece, the center of curvature of the imaging-side lens mirror piece, and the arrangement direction of the mold moving means. Means for calculating the eccentricity on the basis of the position in (1), an eccentricity measuring apparatus for a mirror piece for a lens in an optical imaging element molding die. 2. A method for measuring the eccentricity of a mirror piece for a lens in a mold for molding an optical imaging element using the eccentricity measuring device according to claim 1, wherein a motion error accompanying movement of the mold moving means is measured. A method for measuring the eccentricity of a mirror piece for a lens in a mold for forming an optical imaging element, wherein an error given to the lens is corrected using a multipoint algorithm. 3. A method for measuring the eccentricity of a mirror surface piece for a lens in an optical imaging element molding die using the eccentricity measurement device according to claim 1, wherein the optical system for the entrance side and the imaging side lens mirror piece is provided. Correcting the error in the multipoint method calculation process caused by the spacing error of the center of curvature of the lens mirror piece detected in the above by using the measured value of the spacing error of the center of curvature of the lens mirror piece. A method for measuring the eccentricity of a lens mirror piece in a mold. 4. A method for measuring the eccentricity of a mirror piece for a lens in an optical imaging element molding die using the eccentricity measuring apparatus according to claim 1, wherein the optical system for a lens piece on the incident side is used to measure the eccentricity of the lens piece. The presence / absence of the reflected image signal from the lens mirror piece by the optical system for the lens mirror piece on the imaging side by moving the optical system position adjusting means for the lens mirror piece on the incident side while observing the presence or absence of the reflected image signal of By moving the optical system position adjusting means for the imaging side lens mirror piece while observing the position, the positions of the optical system for the entrance side and the imaging side lens mirror piece are optimized for performing eccentricity measurement. Eccentricity measuring method of a mirror surface piece for a lens in a mold for molding an optical imaging element. 5. A method for measuring the eccentricity of a mirror surface piece for a lens in an optical imaging element molding die using the eccentricity measurement device according to claim 1, wherein the optical system for a lens surface piece on the incident side is used to measure the eccentricity of the lens surface piece. While observing the reflected image, by moving the focus adjustment means for the entrance-side lens mirror piece optical system, and while observing the reflected image from the lens mirror piece by the imaging-side lens mirror piece optical system, By moving the focus adjusting means for the optical system for the lens mirror piece on the imaging side, the optimal focus adjustment for performing the eccentricity measurement of the optical system for the lens mirror piece on the incident side and the imaging side is performed. A method for measuring the eccentricity of a mirror piece for a lens in a mold for molding an optical imaging element. 6. A method for measuring the eccentricity of a mirror surface piece for a lens in an optical imaging element molding die using the eccentricity measurement device according to claim 1, wherein the reflected images from the lens mirror pieces on the entrance side and the image forming side are provided. In addition to the light intensity adjusting means, the optical system for the lens mirror piece on the entrance side and the image forming side observes the reflection image from the lens mirror piece while optimally setting the light intensity of the reflected image to perform the eccentricity measurement. A method for measuring the eccentricity of a mirror piece for a lens in a mold for molding an optical imaging element.