JP3385082B2 - Aspherical surface measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] BACKGROUND OF THE INVENTION 1. Field of the Invention
Regarding the aspherical surface measuring device that measures using the Raffy technology
You. [0002] 2. Description of the Related Art In recent years, optical devices such as
Aspherical lenses are often used for camera lenses.
ing. This is due to advances in optical plastic molding technology.
Aspheric lenses can be mass-produced relatively inexpensively.
It is because. Aspherical shape during mass production of aspherical lens
Quickly whether or not is formed with high accuracy as designed
Need to measure. Conventionally, as a method of measuring an aspherical surface, holographic
One utilizing fee technology is known. Applicant
Also developed and applied for an aspherical surface measurement method and measurement device first
(JP-A-4-40534). This applicant first
The newly developed aspherical surface measuring device has been designed with high accuracy
Reflected light and reference from an accurately formed and positioned aspheric prototype
An image is taken by superimposing the light on the light to form a hologram. Next
The hologram is returned to the shooting position after the
The aspherical lens that is the test surface is placed at the same position as the aspherical prototype.
Then, the interference fringes observed on the observation surface
Easily measure shape errors from design values, which are differences from surface prototypes
It becomes possible. However, actually, the outer shape of the aspherical lens
Molding error when mounting the aspherical lens on the measuring device.
Alignment error may occur in the resulting interference fringes due to
Is included. Adjustment work to remove this alignment error
Is very difficult and takes a lot of time to adjust
Was. That is, in spherical measurement, the XYZ coordinate system
Only the translational adjustment of the three axes was sufficient.
A total of 5 axes including tilts Δθx and Δθy around the X and Y axes
Adjustment was necessary. Here, the Z axis is to the lens to be inspected.
The incident direction of the test light, that is, the aspheric lens is placed
The optical axes O, X, and Y of the optical path are two orthogonal directions perpendicular to the optical axis O.
You. In general, the surface to be inspected has δx in the X-axis direction,
Direction, the interference fringes have
Component (tilt fringe) and coma component in the direction of
Patterns (interference fringes) containing (coma aberration fringes) are observed
It is. On the other hand, Δθx and Δθy tilt around the X and Y axes, respectively.
If it is, most of the tilt components will be in the interference fringes
And a pattern containing a slight coma component was observed.
It is. Dryness due to only the tilt component and coma
The appearance of the interference fringes is shown in FIG. 2 (B) and FIG. 3 (B).
did. When coma is included in the tilt component, FIG.
It appears as shown in Also, the displacement of the test surface in the Z-axis direction
Causes a defocus component in the interference fringes. Generally, this
These three errors overlap and interference fringes are observed.
Here, the defocus component is axially symmetric unlike other errors
Appears as a pattern and can be adjusted relatively easily
(See FIG. 4B). However, errors due to lateral displacement and inclination of the surface to be inspected.
Generate interference fringes that are close to each other, making it difficult to separate them from each other.
It is difficult to adjust the lens alignment by trial and error.
There was a problem that the adjustment time was long due to the increase in floors. [0007] Also, it is noted that some coarse interference fringes can be obtained.
Manual adjustment until the
Fringe scan method using computer and scanning means
Method to obtain and adjust by interference fringe analysis method such as
Are known. But according to this method, as a whole
Equipment is expensive and fringe analysis time is long.
Therefore, it is difficult to apply the method to mass production. [0008] SUMMARY OF THE INVENTION The present invention relates to a method for measuring optical elements, especially aspherical surfaces.
In this case, alignment adjustment is easy with a simple configuration,
Provide an aspherical measuring device that can be performed in a short time
In addition, especially when measuring multiple aspherical lenses.
The purpose is to facilitate adjustment of the adjustment. [0009] SUMMARY OF THE INVENTION The present invention, which achieves this object, provides a coherent
Splits the light beam from the light source, one of which is the test surface of the test optical element
And the test light reflected by the test surface and the coherent light
The other part of the luminous flux from the source is
After diffracting in grams, superimpose on the observation surface and interfere
Measuring device having a measuring optical system for forming interference fringes
Thus, the direction in which the reference light is incident on the hologram is adjusted.
Adjusting means for adjusting,0th order of hologram by reference light
Focus the diffracted light or first-order diffracted light on the detection surface
ByThe reference light enters or exits the hologram.
Detecting means for detecting the direction in which the
I do. [0010] DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on illustrated embodiments.
You. First, an alignment adjustment device to which the present invention is applied is provided.
The principle of the obtained aspherical surface measuring device is explained with reference to FIG.
I will tell. Laser oscillator as a light source that emits coherent light
The laser beam emitted from the objective lens 13 and the core
The light beam is converted into a large-diameter parallel light beam by the remate lens 15. this
The light beam passes through the second half mirror 33 and the first half mirror.
17 and converged by the condenser lens 19,
Aspherical surface (test surface) 2 of the aspherical lens 21 disposed at the position
The light is reflected at 1a, travels backward in the optical path, and passes through the condenser lens 19.
Then, the light is reflected by the first half mirror 17 in a substantially right angle direction.
Then, the light passes through the hologram 23 arranged on the recording surface 51.
The imaging lens 25 controls the CCD image sensor 27.
An image is formed on a photosensitive surface (observation surface 53). Where the test light
Is incident on the aspherical lens 21, that is, the condenser lens
The optical axis 19 is the optical axis O of the measuring optical system, and the X, Y, Z
This is the Z axis of the reference system. The aspherical lens 21 includes the lens holder 1 to be inspected.
00. Here, measurement in the mass production process
In consideration of workability, the measuring device is inevitably
The lens holder 100 is disposed vertically below,
The measurement optical system and the measurement device are arranged vertically above. This
Lens holder 100 fits and holds aspherical lens 21
Between the lens mounting recess 101 and the lens mounting recess 101
It has a circular hole 104 formed in the bottom 103.
The inner peripheral surface of the lens mounting recess 101 is
The aspherical lens 21 is almost vertically straight in contact with the peripheral portion.
The lens guide surface 102 that guides the
Make up. If the contact surface of the aspherical lens is convex,
When the upper peripheral edge 105 of the hole 104 comes into contact with the aspherical lens,
Holds the aspherical lens and the contact surface of the aspherical lens is concave.
Sometimes, the bottom surface 103 comes into contact with the periphery of the aspherical lens.
To hold the aspherical lens. In this embodiment, the aspheric lens
, The second surface 21b is in contact with the upper peripheral edge portion 105 and is held.
Is held. Further, the lens holder 100 is provided with a moving slide.
It is possible to move in the optical axis O (Z axis) direction
Translational movement in the direction perpendicular to the axis (XY axis direction)
Supported as possible. This movement in the Z-axis direction
Adjust the focus by adjusting the lateral displacement by moving in the X and Y directions.
Make adjustments. The hologram 23 has a very high resolution as a medium.
A photosensitive material is used, and the lens holding base 100
Place an aspherical prototype (not shown) and place it on the recording surface 51
Light from the aspherical prototype and the reference
It is recorded (exposure and development) by irradiating with light
You. On the other hand, the laser beam emitted from the laser
Part of the parallel light beam transmitted through the half mirror 33 is
In the half mirror 17, the CCD image sensor 27
Is reflected in the opposite direction, and furthermore, the fixed reference mirror 29 and
Reflected by the movable reference mirror 31 and the first half mirror
-17 through the hologram 23. And
The light beam incident on the hologram 23 is reflected by the hologram 23
Diffracted, in the same direction as the test light from the aspheric lens 21
Then, the image forming lens 25 moves the CCD image sensor 27
Imaged on top. Reflected by these reference mirrors 29 and 31
The obtained parallel light beam becomes the reference light. Here, in the present embodiment, the movable reference mirror 3
1 can be rotated in two directions perpendicular to the normal of the reflective surface
I have. Note that these two directions are within the plane of FIG.
And the direction perpendicular to the paper surface. The aspherical surface 21a of the aspherical lens 21
The emitted test light and reflected by the reference mirrors 29 and 31
Interference fringes due to superimposition with the reference light
The image is taken by the sensor 27. This interference fringe is
55, the difference from the aspherical shape, that is, the difference from the design shape
Is obtained as Therefore, the CCD image sensor 2
7 is reproduced on the TV monitor 41.
By observing or measuring the aspherical lens 21
It is possible to know the processing accuracy and condition of Also watch here
The interference fringes measured are the same as when recording an aspheric
To use the same optical system as when measuring
That is, the condenser lens 19 and the first half mirror 17
Since the bundle passes, when recording an aspherical prototype and measuring the shape of the lens to be inspected
Sometimes the aberrations of the optical system cancel each other out, and
No measurement error occurs due to the optical system. Further, the aspherical surface 21a (test surface) and the
Program 23 (recording surface) is disposed in a conjugate relationship, and
Hologram 23 and CCD image sensor 27 (observation surface)
Are arranged in a conjugate relationship. In such a conjugate relationship
By arranging, the coordinates on the test surface and the
The coordinates correspond one-to-one with the coordinates of the reference light when measuring the test lens.
Aberration even when tilt (angle of incidence on hologram 23) is changed
And the alignment adjustment becomes easy. In this embodiment, measurement of a spherical lens is also possible.
Noh. Parallel light emitted from the collimating lens 15
Part of the bundle is almost perpendicular to the second half mirror 33
To the third mirror, which is reflected by the mirror and further creates a second reference beam.
-35, the light is reflected by -35 and travels backward in the optical path.
3 through the imaging lens 37 and the CCD image sensor.
An image is formed on the surface 39. Also, the second half mirror 33
The transmitted light beam is reflected by the converging lens 19 on the surface to be inspected.
And is reflected by the second half mirror 33 in the reverse direction of the optical path,
Formed on the CCD image sensor 39 by the imaging lens 37
Imaged. These two lights are superimposed to form a CCD image cell.
An interference fringe is obtained on the sensor 39. This interference fringe is
The image is captured by the image sensor 39 and projected on the TV monitor 42.
Measuring the spherical shape of a spherical lens
Can be. When the surface to be measured is an aspheric lens,
The converging lens 19 reflected by the aspherical surface 21a of the surface lens 21
A part of the light beam transmitted through the first half mirror 17 is transmitted.
To reverse the optical path to the second half mirror 33 as a parallel light flux
To the image forming lens 37 by the second half mirror 33.
And reaches the CCD image sensor 39. did
Therefore, the light reflected by the third mirror 35 and the aspherical lens
The test light reflected by the sensor 21 is dried on the light receiving surface of the sensor 39.
Interference fringes are formed. Observing this interference fringe
Check of the alignment state of the aspherical lens 21
Can be done. However, the rough part of the interference fringes is
Therefore, it is difficult to measure depending on the test surface. In addition, aspherical lens
There is no tilt, coma and various aberrations of the lens 21.
Otherwise, the interference fringes are concentric. The misalignment of the aspherical lens 21 will now be described.
The difference, that is to say the measuring device, relative to the aspherical prototype
If there is an error that occurs when the setting position is different,
On the observation surface 53 due to
This produces interference fringes. 2 to 4 show only the tilt,
Only coma and defocus only
The state of the wavefront when it occurs in each is shown.
In the figure, the symbol (A) indicates the wavefront yield on the observation surface 53.
A diagram in which the difference is plotted three-dimensionally.
3 is a front view showing the appearance of interference fringes, and symbol (C) is
(A) In a longitudinal section passing through the optical axis O and the Y axis in the drawing.
FIG. 3 is a diagram showing wavefront aberrations. When measuring the aspherical shape of an aspherical lens,
In general, first, as described above, the reference aspherical element
The hologram 23 is formed by exposing and developing with a container. When the hologram 23 is completed, the hologram 23
23 is set at a predetermined position, and then the aspherical lens 2
1 is placed on the lens holder 100, and X,
The deviation adjustment in the Y and Z axis directions is performed. Lens holder 100
Is located vertically below, and the measuring optical system and measuring device
Are arranged vertically above. Here, the deflection of the aspheric surface itself is
Not only the center (lateral shift) and tilt, but also the lens holder 100
Opposing surface 21 of aspherical lens 21 on lens holding edge 104
Since b is applied, the aspherical lens for the applied part
Is tilted with respect to the optical axis O, and the lens guide surface
Clear run between 102 and peripheral contour of aspheric lens 21
The aspherical lens 21 to be measured is necessarily
The inclination Δθx, Δθy and the lateral deviation δx with respect to the optical axis O,
δy. Next, the adjustment method in this embodiment will be described.
A description will be given in comparison with a conventional adjustment method. Test aspheric surface
The lens 21 has an effective radius of 7.20 mm and an aspherical surface 21a.
This is an aspheric lens represented by an aspheric surface formula 1. (Equation 1) Paraxial r: -27.682 (mm) k: 0.00000 α_Four ： -2.79670 × 10^-Five α₆ ： 7.25141 × 10^-8 α₈ ： -6.30504 × 10^-9 α_Ten, Α₁₂: 0.00000 × 10^-0 The aspheric surface 21a to be inspected has an effective radius (h
= Hmax), the amount of aspherical surface is 0.111 mm, and λ = 0.6328 μm.
In this case, it becomes an aspherical surface which generates a wavefront aberration of 350 λ in a round trip. This
Here, as an alignment error of the test aspheric surface 21a,
When Δθ is 1 ′ and the lateral shift δ (the direction is arbitrary)
In each case when 10 μm exists,
Interference fringes based on tilt error (hereinafter “tilt fringes”
) And coma (hereinafter “coma aberration fringes”)
The number of interference fringes shown in Table 1 was observed.
Is done. [Table 1] Table 1 shows the inclination Δθ of the test aspheric surface and
Lateral shift δ, tilt fringes of observed interference fringes and
The relation with coma aberration fringes is shown. In this example,
When a slope Δθ of 1 ′ occurs on the spherical surface, a tilt fringe is 13.2
0.65 lines and coma aberration fringes appear, laterally offset to the aspheric surface to be inspected
When δ is 10 μm, 16.4 tilt stripes,
6.70 stripes appear. The characteristic feature here is that the inclination Δθ of the test surface is
The effect is greatly related to the number of tilt stripes.
Has little to do with aberration fringes (however, 0
No), and the lateral shift δ is large in the number of coma fringes
It is closely related. The conventional adjustment procedure and wave under such conditions
The relationship with the surface aberration will be described with reference to Table 2. Conventional
In the method of adjusting the alignment of the aspherical lens for inspection,
Tilt the body with respect to the optical axis, and
And adjust the tilt and lateral displacement independently.
This was done in a standing adjustment stage. Where the slope Δθ
Is 1 'and the lateral deviation δ is 10 μm,
If the difference was in the same direction, 29.6 tilt stripes
(13.2 + 16.4 = 29.6), 7.35 coma aberration patterns (0.65+
3.7 = 7.35) When it is shown (see (1) in Table 2)
The conventional adjustment method in FIG.
You. [Table 2]First, an error caused by an alignment error
In order to check the number of coma
The number of tilt stripes that occur more than the
Reduce. Therefore, the characteristics of the test surface and interference fringes described above
First, the inclination of the test surface is adjusted. Here, the test non
When the inclination of the spherical surface Δθa is small, the number of generated tilt stripes is small.
Times Δθa = (29.6 / 13.2) ≒ 2.4 '
Adjust the rotation. By adjusting the inclination Δθa, the inclination Δθ =
-1.2 ', zero tilt fringes, 5.89 coma fringes
(−2.2 × 0.65 + 7.35 = 5.89) (see Table 2 (2))
See). Next, the 5.89 coma fringes are set to zero.
Therefore, δa =
(5.89 / 6.70) × 10 ≒ 8.8 μm. This side
By adjusting the deviation δa, the lateral deviation δ = 1.2 μm, coma aberration
The stripes are 0, but -14.4 tilt stripes are generated.
(See Table 2 (3)). Here, the remaining
Ma aberration fringes are 0, but many tilt fringes occur
Therefore, the state cannot be visually recognized. Therefore, this time, the number of tilt stripes should be reduced to zero.
The tilt Δθa of the aspheric surface to be measured is changed in the direction in which the tilt fringe decreases.
In addition, adjust the rotation by Δθa = (14.4 / 13.2) ≒ 1.1 '
You. By adjusting the inclination Δθa, the inclination Δθ = −0.1
 ', Tilt fringe is 0, but coma fringe is about 0.7
One occurs (see Table 2 (4)). Then, again, the coma aberration fringe is reduced to zero.
Δa = 10 ×
(0.71 / 6.70) ≒ Move by 1.1 μm. But this
The lateral deviation δ becomes 0.2 μm by adjusting the lateral deviation of
Aberration fringes become zero, but -1.7 tilt fringes occur
(See Table 2 (5)). Where the book with tilt stripes
Finally, the number of coma aberration fringes has decreased
Has become zero. As described above, the adjustment of the inclination Δθa of the aspheric surface to be inspected is performed.
Adjustment of the lateral shift δ in the direction orthogonal to the optical axis
And the number of tilt fringes and the number of coma fringes are below the allowable values
It repeats many times until it becomes. The conventional adjustment method described above uses the aspherical surface to be inspected.
When the tilt of the optical axis is adjusted, no lateral shift δ occurs.
The explanation was based on the assumption that
In order for the axis of rotation of the surface to be measured to stand up
Heart). In practice, this assumption is necessary.
This is not the case, and if this condition breaks down, many adjustments will not be possible.
There was a problem that it required a lot of time. Moreover
Conventional adjustment methods include interference fringes and coma due to tilt errors.
The interference fringes due to
The adjustment when the condition is broken as described above is complicated. From this conventional measuring method, the alignment
What is important in adjustment is that the coma aberration component, which is necessary information, is not required
To avoid being buried in the tilt component, which is important information.
What makes visual recognition easy, and the ease of visual recognition is adjusted
It can be seen that the magnitude between the two is determined. The present invention has been made based on such an analysis.
The description will be further made with reference to FIGS. Observation
FIG. 6 is a graph showing the state of interference fringes passing through the optical axis in a planar shape.
It was shown to. In FIG. 6, the horizontal axis ρ represents the aspherical lens 21.
The height (radius) from the optical axis is h, and the effective height is hmax (Yes
Effective radius D), the value represented by h / hmax
The vertical axis Δω (book) is the amount of deformation of the interference fringes. already
The values in Table 1 described above are the values of ρ = 1 in this graph. This
From the graph of FIG. 5, the deformation amount Δω of the interference fringe is the lateral shift δ of the aspheric surface.
And the amount of dependence on the slope Δ depends on the lateral shift δ of the aspheric surface.
It can be seen that it has a characteristic that it is sufficiently smaller than that. The measuring apparatus of the present invention made by focusing on this point.
The coma component and tilt component are separated
It is characterized in that it can be adjusted vertically. That is, initially
Tilt the set reference beam at the time of alignment adjustment,
Tilt component caused by alignment error of the aspheric surface
Only the minute is corrected independently to improve the efficiency of adjustment.
You. Specifically, the adjustment of the coma aberration component is
The tilt component is adjusted by moving the
Do not tilt the spherical lens but tilt the reference beam
It has features. As described above, the apparatus of the present embodiment
All coma components of the spherical surface are not translated by the aspherical lens under test.
It can be solved only by adjustment. Operation of the embodiment for realizing the idea of the present invention
The principle will be further described with reference to FIG. Figure 7
Therefore, the direction orthogonal to the plane of the paper is the X axis, and the X axis
An axis perpendicular to the optical axis O is defined as a Y axis. Movable reference
The X axis is an axis whose extension is perpendicular to the center of the reflecting surface.
It is configured to be rotatable about the direction axis and the Y-axis direction axis.
Have been. Here, the movable reference mirror 31 is connected to the X-axis direction axis.
Let's consider the case of tilting Δφ around. The communication shown in FIG.
When the movable reference mirror 31 is tilted by Δφ, the hologram 2
The reference light incident on 3 has an incident angle of 2Δφ. Further e
The reference light diffracted by the program 23 passes through the imaging lens 25.
The light is transmitted and enters the observation surface 53 at an incident angle α. here,
With respect to the imaging lens 25, the hologram 23 and the observation surface 53
Is conjugate, the imaging magnification of the imaging lens 25 is m
Then, the incident angle α is α = 2mΔφ. Further, in this example, the test surface and the observation surface are
It is conjugate. Here, diffracted by the hologram and imaged
The light beam transmitted through the lens 25 simply tilts by α,
The wavefront shape itself of the diffracted wavefront does not change. But
Therefore, the reference light incident on the observation surface 53 at the incident angle α is
The hologram 23 is transmitted by reflected light from the test aspheric surface 21a.
After passing through the formed light (object light) and the imaging lens 25,
Overlap on the measurement surface 53, and as a result, interference fringes are formed.
At this time, if the luminous flux diameter on the observation surface 53 is D, k = Dα A certain number of stripes, that is, interference fringes caused by tilt
Only k lines are observed, and no coma aberration occurs. In FIG.
In the embodiment shown, nine tilt stripes are generated.
I understand. In this embodiment, the movable reference mirror 31 is
It is characterized by
You. The movable reference mirror 31 is tilted by 1 '(tilted)
Table 3 shows the number of interference fringes that sometimes occurred. This Table 3
Is obtained when the inclination Δφ of the movable reference mirror 31 increases or decreases by 1 ′.
31.9 tilt fringes are generated, but coma fringes are 0
It indicates that there is. [Table 3] Next, the adjusting method and the adjusting apparatus of the present invention will be described.
The adjustment by the method will be further described with reference to Table 4 and FIG.
I will tell. In the present embodiment, the aspherical lens 21 is
And move it only in the direction perpendicular to it, and
The feature is that the rotation of the movable reference mirror 31 is adjusted.
You. [Table 4]First, the aspherical lens 21 to be inspected is replaced with the lens to be inspected.
It is set on the holding table 100 (step (S) 11). So
If defocus has occurred, the aspherical lens 2
1 (test lens holder 100) is moved and adjusted in the Z-axis direction.
Defocus is set to 0 (S13). After the defocus adjustment, the aspheric surface 21a
Slope Δθ and lateral shift δ are the alignment errors.
In the same direction, an inclination Δθ of 1 ′ and a lateral deviation δ of 10 μm were generated.
Suppose you were. This is based on the same conditions as (1) in Table 2.
is there. In this case, 29.6 tilt stripes and coma aberration stripes
Was 7.35 (see (1) in Table 4). Therefore, first, the tilt stripes should be reduced to zero.
Next, the rotation of the movable reference mirror 31 is adjusted (S15). This
Since there are 29.6 tilt stripes, the movable reference mirror
-31 in the direction to cancel the tilt stripes (29.6 / 31.9)
≒ 0.93 'rotation to initialize the movable reference mirror 31
The inclination from the direction Δφ is -0.9 ', and the tilt fringe is 0
I do. As a result of this operation, the lateral shift δ of the aspherical lens 21 is
7.35 coma aberration fringes remained (Table 4
(See (2)). Next, in order to reduce the coma aberration fringe to 0, the aspherical surface
Move the lens 21 by 11 μm in the direction to cancel coma
(S17). By this movement, the lateral shift δ becomes -1 μm
However, the coma aberration fringe becomes zero. Till in this process
However, a movable reference error is generated independently of the adjustment of the test surface.
If you tilt the R31, the number of tilt stripes will not increase,
It can be a book. With the above operation, tilt
The fringes and coma fringes are almost zero. In addition, movable reference
The tilt Δφ of the mirror 31 is reduced by 0.6 ′ to about 0.4 ′.
ing. With the above adjustments, tilt stripes and
The absolute value of the remaining amount after adjusting the fringe pattern has fallen below the allowable value
Measure the shape error of the test surface caused by processing errors, etc.
Then, the quality of the test aspheric surface 21a is determined (S19, S2).
1, S23). When the judgment is completed, the aspheric lens 2 to be inspected
1 is removed from the lens holder 100, and based on the above judgment,
Process. Then, a new test aspheric lens is
The processing of S11 to S23 is carried on the
Perform As described above, in this aspherical surface measuring device,
The inclination of the aspherical surface 21a (the aspherical lens 21 with respect to the optical axis O)
The tilt of the optical axis of the
Adjusting the angle of the movable reference mirror 31 without tilting the spherical surface 21a
To adjust the incident angle of the reference beam,
The surface 21a only needs to be adjusted for the lateral displacement. Moreover, the reference light
Tilt does not affect coma fringes,
Separate tilt and coma fringes for independent adjustment
As a result, the alignment adjustment time of the aspheric surface
Can be shortened to In the illustrated embodiment, in order to tilt the reference light,
Although the movable reference mirror 31 is rotated, the movable reference mirror 3 is rotated.
1 and the fixed reference mirror 29 may be interchanged,
The angle at which the reference beam is incident on the hologram and observation surface (optical axis
Any configuration can be used as long as it can adjust the angle with respect to O). By the way, in this measuring device, various non-
When measuring a spherical lens, the hologram is
It is manufactured in advance according to the spherical lens.
It must be replaced with a corresponding hologram. In this embodiment
Is a movable part when measuring the aspherical shape of an aspherical lens.
The illumination mirror 31 is moved. Therefore, the movable reference mirror 31
The angle of incidence of the reference beam reflected by the
The difference between hologram recording and hologram replacement
Sometimes For example, after recording a hologram,
Alignment when measuring aspherical lenses using holograms
When the movable reference mirror 31 is rotated and adjusted for
It is. Therefore, in this case, the hologram
Conditions, such as the position and angle of the reference beam incident on the observation surface
However, it differs between recording and hologram replacement. However, the reference beam striking the hologram
Must be the same for hologram recording and exchange.
is there. Otherwise, the hologram adjustment will be incorrect
I can't do it. In other words, set the aspherical prototype, and from the prototype
Light that is transmitted through the hologram with the reflected light (0th-order diffracted light)
The number of interference fringes due to light diffracting the hologram by illumination is 0
I can't book it. Therefore, according to the present invention, the reference light enters the hologram.
Hologram recording by detecting the launch angle, direction or position.
A device that can be adjusted to the same incident conditions for recording and exchange
Offer. This embodiment of the invention is not further illustrated in FIG.
This will be described with reference to FIG. In addition, the implementation shown in FIG.
The same components as those in the example are denoted by the same reference numerals, and description thereof is omitted.
I do. FIG. 9 shows a reference transmitted through the hologram 23.
The inclination of the movable reference mirror 31 is detected by light (0th-order diffracted light).
An example is shown. Reflected by movable reference mirror 31
Through the first half mirror 17 and the hologram 23.
The passed reference light (0th-order diffracted light) is condensed by the condenser lens 63.
CCD image sensor 6 whose light receiving surface constitutes a detection surface
5 is formed. The image of this reference light is represented as a point image 66.
(See FIG. 10), the point image 66 is displayed on the TV monitor.
It is projected on 67 and observed. Here, when recording the hologram
Record the position (coordinates) of the point image 66 at
At the time of gram exchange, the recorded position is read and the
Adjustment of the movable reference mirror 31 so that the point image 66 comes to
Perform Hologram 23 is recorded by this angle adjustment
Hologram with reference light incident at the same angle as
System incidence can be set. The condenser lens 63, CCD
The image sensor 65 constitutes detection means. When a hologram is recorded, a point image is
Adjust the angle of the movable reference mirror 31 so that it is positioned at the target
With this configuration, a point image 66 is formed every time various holograms are recorded.
No need to record coordinates. The hologram of the reference beam
The means for detecting the shooting position includes a condenser lens 63 and a CCD image.
Limited to image sensor 65 and TV monitor 67
is not. The above is an actual case using transmitted light (0th-order diffracted light).
This is an example, but an example using first-order diffracted light
This will be described with reference to FIG. Hologram 23 and imaging lens
A third half mirror 71 is disposed between the
You. First half mirror 1 reflected by movable reference mirror 31
7 and a part of the reference light diffracted by the hologram 23
Is the direction perpendicular to the observation surface 53 by the third half mirror 71
Reflects in the direction. This third half mirror 71 reflects
The reference light is supplied to the CCD image sensor by the condenser lens 73.
The image is formed at 75. This reference light image is represented as a point image.
Is displayed on the TV monitor 77 and observed.
Record again. In this embodiment, on the observation surface,
The reflected light can be observed as a point image.
Angle deviation can be measured, and the inclination information of the test surface can be obtained.
There is also a feature. As described above, in this embodiment, the light is incident on the hologram.
The position of the reference light to be detected can be detected.
When exchanging holograms to measure noise
It will be the same position as the reference light incident position at the time of hologram recording
The angle of the movable reference mirror 31 can be adjusted as
You. Therefore, by moving the movable reference mirror 31,
To remove the adverse effects caused by the movement of the movable reference mirror 31
Quick adjustment and lateral displacement adjustment of the aspherical lens 21a
In a short time. [0055] As is apparent from the above description, according to the present invention,
Then, the 0th order diffracted light or the 1st order of the hologram by the reference light
The diffracted light is focused on the detection surface, and the position of the reference light
Detects the direction of incidence or exit to the hologram
Since it can be detected by steps, the reference light
The conditions for incidence on the gram are different from those during hologram recording.
EvenFocusing of reference beam by detecting means during hologram recording
If the position is detected, the reference light at the time of measurement
Adjustment so that the light focus position matches the light focus position during recording
If adjusted by means,Same conditions as for hologram recording
Can be adjusted in different ways, so the light after replacing various holograms
Easy, quick and short measurement of the element
Easy alignment adjustment when measuring multiple aspherical lenses
Easy and quick.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an optical path diagram of an embodiment of an aspherical surface measuring apparatus using a hologram to which the present invention is applied. FIG. 2 is a diagram showing a state of an interference fringe caused by a tilt of a test aspherical surface, which is shown on an observation surface of the measurement apparatus, in a three-dimensional shape, a plane, and a cross-section. FIG. 3 is a diagram showing the appearance of interference fringes due to coma aberration of the aspheric surface to be detected, which is shown on the observation surface of the measurement apparatus, in a three-dimensional, planar, and cross-sectional view. FIG. 4 is a diagram showing a state of an interference fringe due to defocusing of the aspheric surface to be detected, which is shown on the observation surface of the measurement apparatus, in a three-dimensional shape, a plane, and a cross-section. FIG. 5 is a plan view showing the appearance of interference fringes due to tilt and coma aberration on the surface to be inspected, which is shown on the observation surface of the measuring apparatus. [6] tilt Δθ 1 ', is a graph showing a state of bending of the interference fringes when the lateral deviation δ occurs 10 [mu] m. FIG. 7 is a diagram illustrating the relationship between the rotation angle of the movable reference mirror and the deflection of the reference light in the present embodiment. [8] Flowchart illustrating the measurement procedure of this embodiment
FIG . FIG. 9 is an optical path diagram showing one embodiment of a reference light incident position detecting means in the present invention. FIG. 10 is a diagram showing a state of an image obtained by the reference light incident position detecting means. FIG. 11 is an optical path diagram showing another embodiment of the reference light incident position detecting means in the present invention.

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁷ , DB name) G01M 11/00-11/02 G02B 9/021 G01J 3/45 G01J 9/00-9/04

Claims (1)

(57) [Claim 1] A light beam from a coherent light source is split, and one of the light beams is radiated to a surface to be measured of an optical element to be measured and reflected by the surface to be measured. and test light, and the other obtained by dividing the light beam from the coherent light source as a ginseng <br/> illumination, forming interference fringes by interference superimposed on the observation plane after being diffracted by the hologram optical measurement A measuring device having a system, comprising: adjusting means for adjusting a direction in which the reference light is incident on the hologram; and a zero-order diffracted light or a first-order diffracted light of the hologram by the reference light.
An aspherical surface measuring device, comprising: detecting means for converging the folded light on a detection surface and detecting a direction in which the reference light enters or exits the hologram according to the position thereof .