JP2006145387A - Eccentricity measuring instrument for lens system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an eccentricity measuring instrument for a lens system capable of measuring precisely an eccentric level of a measured lens, irrespective of arrangement of the measured lens. <P>SOLUTION: This eccentricity measuring instrument 1 is provided with a light source part 2, a zoom optical part 11 having a plurality of moving lenses, and for regulating a condensing position of a light beam from the light source part 2 on a measured face concerned in a measured lens part 10 arranged with the measured lens, a personal computer (control part) 13 for controlling positions of the moving lenses, an observation optical part 15 for observing a reflected image from the measured face, a computing part 16 for calculating the eccentric level of the measured face, based on a shift amount between a reflected image position image-focused in the observation optical part 15 and a reference position on the measured face, and a measured lens support part 17 capable of inverting an incident direction of the beam from the light source part 2 to the measured lens part 10. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a lens system eccentricity measuring device for measuring the amount of eccentricity of each surface in a lens system such as a camera.

In lens system eccentricity measurement, a method of measuring the amount of eccentricity by a method called an autocollimation method after fixing a lens portion to be measured in an actual use state to the apparatus has been proposed (for example, see Patent Document 1).
In the measurement by the autocollimation method, for example, as shown in FIG. 11, the zoom optical unit 102 in which the moving lens 101A (the lens at the moved position is 101B) and the fixed lens 101C are arranged on the same optical axis C. In addition, the measurement is performed using an apparatus in which the measured lens unit 105 including the measured lenses 103A, 103B, and 103C is arranged on the optical axis C of the light source unit 106. At this time, the moving lens 101A is disposed at a position where the measurement light from the light source unit 106 is incident on the measurement target surfaces 107A, 107B, 107C, 107D, 107E, and 107F of the measurement target lenses 103A, 103B, and 103C. Then, the amount of eccentricity is calculated from the amount of deviation between the rotation center of the point image when the lens unit 105 to be measured is rotated about the optical axis C and the position at the start of rotation.

  At this time, in order to accurately observe the reflected images of the measurement target surfaces 107A, 107B, 107C, 107D, 107E, and 107F, it is necessary to clearly separate the reflected images from each other. For this purpose, the spherical positions of the measured surfaces 107A, 107B, 107C, 107D, 107E, and 107F are not observed simultaneously with the reflected image obtained on one measured surface and the reflected image obtained on the other surface. , It must be separated by more than the distance that can be separated and observed.

However, in the above conventional technique, as shown in FIG. 11, the position of the sphere center of the measured surface 107C is the position of the sphere center of any one of the other measured surfaces 107A, 107B, 107D, 107E, 107F. When the distance between the reflected image on the surface to be measured 107C and the reflected image on the other surface to be measured approaches and is observed simultaneously, the observation cannot be performed with high accuracy. There is.
JP-A-5-31670

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a lens system eccentricity measuring apparatus capable of measuring the eccentricity of a lens to be measured with high accuracy regardless of the arrangement of the lens to be measured. .

The present invention employs the following means in order to solve the above problems.
The decentration measuring apparatus according to the present invention has a light source section and a moving lens for adjusting the condensing position that can be moved, from the light source section of the measured surface related to the measured lens section on which the measured lens is arranged. A zoom optical unit that adjusts a light collection position, a control unit that controls the position of the moving lens, an observation optical unit that observes a reflected image from the surface to be measured, and an image formed on the observation optical unit An arithmetic unit that calculates the amount of eccentricity of the surface to be measured based on the amount of deviation between the reflected image position and the reference position of the surface to be measured, and the incident direction of the light beam from the light source unit to the lens unit to be measured is reversed. And a lens-to-be-measured supporting portion that supports the lens-to-be-measured portion in a possible manner.

  This eccentricity measuring device can move the position of the spherical center by changing the position of the surface to be measured and the light source unit by reversing the incident direction of the light beam of the light source unit to the lens to be measured, and the movement corresponding to this. By changing the position of the lens, the reflected image of the surface to be measured can be observed separately from the reflected image of the other surface to be measured.

The eccentricity measuring apparatus according to the present invention is the eccentricity measuring apparatus, wherein the calculation unit can measure the amount of eccentricity regardless of the incident direction of the light beam from the light source unit to the lens unit to be measured. It is said that it is said.
This eccentricity measuring apparatus can suitably measure the amount of eccentricity of the measured surface of the lens to be measured even if the lens to be measured is inverted with respect to the light source by the lens support portion to be measured.

  Further, the decentration measuring apparatus according to the present invention is the decentration measuring apparatus, in which the measured lens support section does not change the shortest distance or the longest distance between the measured lens section and the light source section. The lens unit is moved.

  This decentering measuring device can easily calculate the position of the surface to be measured after inversion using the relative position information of the surface to be measured in the lens portion to be measured before inversion, and the eccentricity of the surface to be measured of the lens to be measured. The amount can be suitably measured.

  According to the present invention, it is possible to change the position of the moving lens corresponding to the position of the sphere center of the surface to be measured, and to accurately measure the amount of eccentricity by forming an image on only the sphere center position of the desired surface to be measured on the observation optical unit. It can be performed.

A first embodiment according to the present invention will be described with reference to FIGS.
As shown in FIGS. 1 and 2, the eccentricity measuring apparatus 1 according to this embodiment includes a light source unit 2, a fixed lens 20, which will be described later, and a movement for moving with respect to the fixed lens 20 for adjusting a light collection position. A surface to be measured 6A, 6B, 7A, 7B, 8A having a lens 3 (a lens at a position after movement is indicated by 5) and having a lens to be measured 10 on which the lenses 6, 7, and 8 to be measured are arranged. , 8B, a zoom optical unit 11 that adjusts the condensing position of the light beam from the light source unit 2, a drive unit 12 that moves the moving lens 3, a personal computer (control unit) 13 that controls the position of the moving lens 3, The observation optical unit 15 for observing the reflected image A from the measurement surfaces 6A, 6B, 7A, 7B, 8A, 8B, the position of the reflected image A formed on the observation optical unit 15, and the measured surfaces 6A, 6B, 7A, 7B , 8A, 8B based on the amount of deviation from the reference position 6A, B, 7A, 7B, 8A, 8B, a calculation unit 16 that calculates the amount of eccentricity, and a target that supports the lens unit 10 to be measured by reversing the incident direction of the light beam from the light source unit 2 to the lens unit 10 to be measured. And a measurement lens support 17.

The light source unit 2 is a laser diode, and can emit a light beam in the direction of the optical axis C.
The zoom optical unit 11 is disposed on the optical axis C so as to face the light source unit 2 via the polarization beam splitter 18. A fixed lens 20 is disposed on the light source unit 2 side of the zoom optical unit 11.
As shown in FIG. 3, the lens-to-be-measured section 10 includes a cylindrical lens housing tube section 21 that houses the lenses to be measured 6, 7, and 8.

The measured lens support portion 17 is formed in a substantially annular shape, and is fitted to the outer peripheral surface of the lens storage tube portion 21 so that the distance from the one end 21A and the other end 21B of the lens storage tube portion 21 is different. A locking portion 22 and a substantially cylindrical connecting portion 23 (to be described later) connected to a rotating portion (not shown) that is connected to the driving portion 12 and rotates the lens portion 10 to be measured about the optical axis C are provided.
Note that when the locking portion 22 is formed integrally with the outer peripheral surface of the lens housing tube portion 21, the measured lens support portion 17 includes a connection portion 23.

Here, for example, in FIG. 4A, the direction in which the incident light enters from the direction in which the one end 21A side of the lens housing tube portion 21 is the upper side is defined as forward incidence, and in FIG. The direction in which the incident light is incident from the direction in which the other end 21B side is the upper side is defined as reverse incidence.
The connecting portion 23 can be fitted to the lens housing cylinder portion 21, and the connecting portion 23 and the locking portion 22 can be brought into contact with each other in a state in which both are fitted. Then, the rotational driving force from the rotating part can be transmitted to the measured lens part 10 by being screwed with the rotating part.

  As shown in FIG. 5A, the connecting portion 23 further includes a forward direction connecting portion 25 that makes the measured lens portion 10 forward incidence, and a measured lens portion 10 as shown in FIG. Is provided with a reverse direction connection portion 26, and the forward direction connection portion 25 and the reverse direction connection portion 26 are formed with different heights. The height of the reverse direction connecting portion 26 is such that the reverse direction incidence is performed in order to reversely move the measured lens portion 10 from the forward incidence to the reverse incidence without changing the shortest distance between the measured lens portion 10 and the light source portion 2. When the distance between the light source unit 2 and the other end 21B of the lens storage tube unit 21 is such that the forward connection unit 25 and the locking unit 22 contact each other, the light source unit 2 and one end of the lens storage tube unit 21 The height is the same as the distance from 21A.

  The lenses to be measured 6, 7, and 8 correspond to the surface numbers from 1 to 6 in the order of the surfaces to be measured 6 A, 6 B, 7 A, 7 B, 8 A, and 8 B in the order of the incident direction of the light source light beam when entering in the forward direction. The respective radii of curvature R and the distance D between adjacent measurement surfaces are configured and arranged as shown in Table 1.

  When the measured lens unit 10 is incident in the reverse direction, surface numbers 1 to 6 are assigned in the order of the measured surfaces 6A, 6B, 7A, 7B, 8A, and 8B that are incident directions of the light source light flux. Table 2 shows the curvature radius R of each measured surface and the distance D between adjacent measured surfaces at this time.

The drive unit 12 is connected to the zoom optical unit 11 and drives the movable lens 3 to move in the direction of the optical axis C with respect to the fixed lens 20.
The observation optical unit 15 includes an observation camera 27 arranged at the condensing position of the reflected light of the polarization beam splitter 18.
Both the observation optical unit 15 and the drive unit 12 are electrically connected to the personal computer 13.

  The light source unit 2, the polarizing beam splitter 18, the zoom optical unit 11, and the observation camera 27 are attached to an optical system support member 28, and the measured lens unit 10 is arranged in an L shape with respect to the optical system support member 28. The measured device support member 17 is attached to the device base member 30.

The calculation unit 16 is arranged in the personal computer 13, and the design of the lens to be measured 6, 7, 8 in the lens unit 10 to be measured and the movable lens 3 and the fixed lens 20 in the zoom optical unit 11 that are input in advance. From the equation, the positions of the spherical center and the corresponding position of the moving lens 3 at the time of forward incidence and reverse incidence of the measured surfaces 6A, 6B, 7A, 7B, 8A, 8B are calculated.
Based on the calculation result, the personal computer 13 instructs the drive unit 12 to move the moving lens 3.

Next, an eccentricity measuring method, an operation and an effect by the eccentricity measuring apparatus 1 according to the present embodiment will be described.
First, the contents shown in Table 1 and Table 2 are input to the personal computer 13 to calculate the position of the ball center, the forward connection portion 25 is attached to the apparatus base member 30, and the locking portion 22 is attached to the lens storage tube portion 21. The lens part 10 to be measured in the arranged state is fitted to the forward connection part 25 with the forward position.

  Next, the driving unit 12 is driven to move the corresponding moving lens 3 to a position where the measurement target surfaces 6A, 6B, 7A, 7B, 8A, and 8B are focused on the calculated spherical positions. Here, since the surface to be measured other than the surface 6A to be measured closest to the light source unit 2 has another surface to be measured between the light source unit 2, the spherical center position determined by the fixed lens 20 and the moving lens 3. Is calculated using design formulas for all surfaces on the light source unit 2 side. Based on the obtained calculation result, the moving lens 3 is moved to a position where the moving lens 3 is condensed on the corresponding spherical center of the measured surface (for example, in FIG. 2, the moving lens 3 is moved to the position indicated by 5. Move it to the auto-collimated state.

  In this state, for example, the reflection image A of the measurement surface captured by the observation camera 27 is in a blurred state A ′ as shown in FIG. Therefore, the moving lens 3 is further moved on the optical axis C and adjusted so as to become a point image as shown in FIG.

At this time, for example, when the movable lens 3 is moved so as to correspond to the spherical center position of the measured surface 7A, as shown in FIG. 6C, the reflected image A of the measured surface 7A and other measured surfaces. In some cases, the reflection image B of the image is observed at the same time.
Therefore, the lens unit 10 to be measured and the forward direction connection unit 25 are separated from each other, and the reverse direction connection unit 26 is screwed into a rotating unit (not shown) instead of the forward direction connection unit 25 so that the lens unit 10 to be measured is moved in the reverse direction. It fits with the connection part 26, and it is made to become reverse direction incidence instead of forward direction incidence.

In this state, the measured lenses 6, 7, 8 are arranged as shown in FIG.
Therefore, the surface number of the design expression of the lens to be measured 6, 7, 8 and the corresponding design value are changed from those for forward incidence to those for backward incidence, and the calculation unit 16 anews them. Recalculate the ball center position.
In this case, the radius of curvature of each surface having a smaller area than the surface to be measured, the distance to the adjacent surface to be measured, and the refractive index of the medium (each lens, air) are different. The ball center position changes. In this state, when the position of the sphere center of the surface to be measured 7A and the position of the sphere center of the surface to be measured forming the reflected image B of FIG. A point image C as shown in (d) is obtained, and the reflected image B from another surface to be measured is not observed.

In this state, the amount of eccentricity is calculated.
That is, the measured lens unit 10 is rotated around the optical axis C by a rotating unit (not shown). At this time, the reflected image A also rotates around the rotation center C1 as shown in FIG. Since the surface to be measured 8B closest to the light source unit 2 is the first surface when calculating the amount of eccentricity, the difference between the rotation center C1 as a reference position and the position at the start of rotation is expressed as dx, dy. The amount of eccentricity is calculated as follows.
For each other measured surface, the amount of deviation from the reference position is obtained while correcting the spherical center position, which is the apparent radius of curvature, and the amount of eccentricity is calculated by the same operation.

  According to the decentering amount measuring apparatus 1, even if the decentration amount cannot be measured with high accuracy by forward incidence, the lens unit 10 to be measured is inverted by the lens support unit 17 to be measured. By reversing the incident direction of the light source part 2 light beam to 8, the positions of the measured surfaces 6A, 6B, 7A, 7B, 8A, 8B and the light source part 2 can be changed, and the spherical center position can be moved. Observation at the same time as an image reflected by another surface to be measured is eliminated. Therefore, only the reflected image of the desired surface to be measured can be formed on the observation optical unit 15 to accurately measure the eccentric amount.

  Further, even if the measured lens unit 10 is inverted with respect to the light source unit 2 by the measured lens support unit 17, the measured surfaces 6A, 6B, 7A, 7B, 8A, 8B of the measured lens unit 10 before the inversion are reversed. The positions of the measured surfaces 6A, 6B, 7A, 7B, 8A, 8B after reversal can be easily calculated using the relative position information, and the measured surfaces 6A, 6B of the measured lenses 6, 7, 8 can be calculated. The eccentric amounts of 7A, 7B, 8A, and 8B can be suitably measured.

Next, a second embodiment will be described with reference to FIG.
In addition, the same code | symbol is attached | subjected to the component similar to 1st Embodiment mentioned above, and description is abbreviate | omitted.
The difference between the second embodiment and the first embodiment is that the device base member 41 in the eccentricity measuring device 40 according to this embodiment is an inverted L shape so that the device base member 41 is on the upper side in the drawing with respect to the optical system support member 42. The arrangement position of the light source unit 43 and the lens unit 10 to be measured is attached in the upside down direction as compared with the case of the first embodiment.

The measurement lens support unit 17 can be attached to the measurement lens unit 10 without changing the longest distance between the measurement lens unit 10 and the light source unit 43. That is, a rotating unit (not shown), a lens support unit 17 to be measured, and a lens unit to be measured 10 are arranged on the upper part of the apparatus base member 41, and the light source unit 43, the polarization beam splitter 18, and the zoom optics are disposed below the apparatus base member 41. The unit 11 and the observation camera 27 are arranged.
These are arranged on the optical axis C, and the light source unit 43 is a semiconductor laser, and the laser beam is irradiated along the optical axis C.

When this eccentricity measuring device 40 is used, the amount of eccentricity is measured by the same method of use as in the first embodiment by assigning a surface number to the measured lens surface that is farthest from the light source unit 43 as one surface. be able to.
At this time, since the light source light beam enters from the direction of the final surface of the lens unit 10 to be measured, it is used in a state where the forward incident direction and the reverse incident direction are reversed when inputting the design formula.

According to the eccentricity measuring device 40, the same operation and effect as the first embodiment can be obtained.
At this time, nothing is arranged in the upper direction of the lens unit 10 to be measured, so that the lens unit 10 to be measured can be attached and measured in any size and shape.
Further, the opportunity for the measurer to directly contact the zoom optical unit 11 and the light source unit 43 can be reduced, and the lens unit 10 to be measured can be easily attached and detached.

The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, the number of moving lenses and lenses to be measured is not limited to the above embodiment.
In addition, the amount of eccentricity in both directions can be measured regardless of forward incidence or backward incidence of the lens to be measured, and comparison with the measurement results of other eccentricity measuring devices can be performed.

  Further, the personal computer may have a function of displaying the position of the moving lens on a display (not shown) and allowing the measurer to confirm it.

It is a perspective view showing the whole eccentricity measuring device composition concerning a 1st embodiment of the present invention. It is explanatory drawing which shows schematic structure of the eccentricity measuring apparatus which concerns on the 1st Embodiment of this invention. It is a perspective view which shows the external appearance of the to-be-measured lens part measured by the eccentricity measuring apparatus which concerns on the 1st Embodiment of this invention. It is explanatory drawing which shows the (a) arrangement | positioning state at the time of forward direction incidence of the lens to be measured measured by the eccentricity measuring apparatus which concerns on the 1st Embodiment of this invention, and (b) the arrangement | positioning state at the time of reverse direction incidence. . FIG. 2A shows a state in which a lens portion to be measured and a lens support portion to be measured, which are measured by the decentration measuring apparatus according to the first embodiment of the present invention, are fitted to each other. FIG. It is a perspective view which shows the state made into. (A) an optical system before adjustment, (b) an optical system after adjustment, and (c) another measurement surface by the eccentricity measuring apparatus according to the first embodiment of the present invention. (D) It is explanatory drawing which shows the case where it becomes separable from other reflected images at the time of reverse incidence. It is explanatory drawing which shows the observation state at the time of forward incidence of the to-be-measured lens measured by the eccentricity measuring apparatus which concerns on the 1st Embodiment of this invention. It is explanatory drawing which shows the observation state at the time of reverse incidence of the to-be-measured lens measured by the eccentricity measuring apparatus which concerns on the 1st Embodiment of this invention. It is explanatory drawing which shows the deviation | shift amount of the spherical center position of the to-be-measured surface measured with the eccentricity measuring apparatus which concerns on the 1st Embodiment of this invention, and a reference position. It is a perspective view showing the whole eccentricity measuring device composition concerning a 1st embodiment of the present invention. It is explanatory drawing which shows the optical system at the time of adjusting the spherical center position of the to-be-measured surface by the eccentricity measuring apparatus by a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 40 Eccentricity measuring apparatus 2, 43 Light source part 3 Moving lens 6, 7, 8 Lens to be measured 6A, 6B, 7A, 7B, 8A, 8B Surface to be measured 10 Lens part to be measured 11 Zoom optical part 13 Personal computer (control part) )
15 Observation optical unit 16 Calculation unit 17 Lens to be measured A Reflected image B Reflected image by the surface to be measured close to the spherical center C Reflected image when the light source light incident direction is reversed

Claims (3)

A light source unit;
A zoom optical unit that has a movable lens for adjusting a condensing position, and that adjusts a condensing position of a light beam from the light source unit on a surface to be measured related to the lens unit to be measured on which the lens to be measured is disposed;
A control unit for controlling the position of the moving lens;
An observation optical unit for observing a reflected image from the measurement surface;
An arithmetic unit that calculates the amount of eccentricity of the surface to be measured based on the amount of deviation between the position of the reflected image formed on the observation optical unit and the reference position of the surface to be measured;
A decentering measurement apparatus for a lens system, comprising: a lens-to-be-measured portion that supports the lens-to-be-measured so that the direction of incidence of a light beam from the light source to the lens-to-be-measured can be reversed. .   2. The decentering of the lens system according to claim 1, wherein the computing unit is capable of measuring the decentering amount regardless of an incident direction of a light beam from the light source unit to the lens unit to be measured. measuring device. 2. The decentration measuring apparatus according to claim 1, wherein the measured lens support unit moves the measured lens unit without changing a shortest distance or a longest distance between the measured lens unit and the light source unit. .

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