JP3381888B2 - Method and apparatus for measuring characteristics of optical elements and the like - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for measuring characteristics such as surface shape, surface accuracy, and internal distortion of an optical element or the like, and more particularly to surface shape and surface accuracy of an object having a highly accurate surface. Etc. can be used for measurement.

[0002]

2. Description of the Related Art The shape of the surface of an element or component, such as an optical element, which requires a highly accurate reflective or transmissive surface,
Conventionally, the surface accuracy and the like have been measured by interference measurement, contact needle measurement, optical stylus measurement, electromagnetic wave beam scanning such as laser measurement, and the like. Of these, interferometry has the great advantage of being able to measure surfaces with high accuracy at one time, but it is difficult to measure aspherical surfaces and especially anamorphic surfaces. While the measuring method using a contact needle may damage or stain the surface, the photo-contact needle does not cause such a problem, but has a problem that the difference in reflectance causes noise and the accuracy deteriorates. In addition, in the measurement by the stylus (including the optical stylus), since the measurement is one-dimensional in principle, there is a problem that two-dimensional measurement takes time. In this respect, the measuring method using electromagnetic beam scanning such as a laser does not have such a problem and can be said to be an excellent measuring method. Therefore, various conventional examples of the measuring method using the electromagnetic beam scanning will be described.

The "method for detecting an abnormality on the surface of a photosensitive layer" described in Japanese Patent Application Laid-Open No. 2-201142 discloses a method of irradiating a laser beam having a high absorbance on a photosensitive layer to detect a laser beam reflected on the surface of the photosensitive layer. It is characterized in that an abnormality on the surface of the photosensitive layer is detected based on optical information.

The "abnormality detection device for the surface of a coating" described in Japanese Patent Laid-Open No. 2-201143 is a device for irradiating the surface of a coating with a laser beam to detect an abnormality on the surface. Scanning means for sequentially scanning light in a predetermined direction, optical path changing means for making the scanned laser light always enter the surface of the coating at a predetermined angle, and means for detecting optical information of the reflected laser light It is equipped with.

The "method of inspecting uneven surface and its apparatus" described in Japanese Patent Application Laid-Open No. 3-295408 at least for an inspection area set in a strip shape having a predetermined width along a straight line on the surface to be inspected. Irradiate parallel coherent ray bundles in a plane orthogonal to the straight line so as to make a predetermined angle with the surface to be inspected, and the diffraction image of the reflected light is relative to the unevenness that can be regarded as a non-defect existing in almost the entire inspection area Is set to be a pattern substantially parallel to the straight line, and the unevenness which locally exists and becomes a defect, the irradiation angle of the light beam bundle is set so as to be a pattern substantially orthogonal to the straight line. Is input to the image input device and image processing is performed to detect the uneven shape of the surface to be inspected.

The "optical three-dimensional shape measuring method and measuring device" described in Japanese Patent Application Laid-Open No. 5-180628 discloses a method of measuring a spot light by scanning the surface of the object with a mirror and detecting the spot light with a sensor. In an optical three-dimensional shape measurement method that measures the surface shape of an object, the surface of a reference measurement object whose measurement dimensions are known is scanned with a spot light using a polygon mirror, and a spot light image from the reference measurement object is detected by a sensor. Then, the difference between the light receiving position data on the sensor by the spot light image and the position data on the sensor of the spot light image derived from the theoretical formula based on the known surface data of the reference measurement object is calculated as Calculate for each position,
The correction calculation value in the surface shape calculation formula of the DUT is calculated, and a loop process for repeating the calculation to obtain a desired correction calculation value is performed, and each correction calculation value corresponding to the value of each parameter is used as a shape calculation table. It is characterized in that it is created and stored, and the surface shape of the measured object is calculated based on the above table when the unknown measured object is measured.

The "three-dimensional electrode appearance inspection device" described in Japanese Patent Laid-Open No. 6-167322 irradiates light on bump electrodes in a three-dimensional array formed on a substrate and receives the reflected light to detect the bump electrodes. The appearance is inspected. A scanning unit that linearly scans the emitted light from the light source with respect to the substrate, a detection unit that receives the reflected light from the bump electrode, and a height of the bump electrode by the detection signal. It is characterized in that it has a height inspection means for inspecting the bump height by calculating and correcting the position based on the scanning timing by the optical scanning means.

[0008]

As described above,
Various types have been published that use an electromagnetic wave beam such as a laser to measure the surface shape and surface accuracy of optical elements and the like, but each has the following drawbacks. .

Both the Japanese Patent Laid-Open No. 2-201142 and Japanese Patent Laid-Open No. 2-201143 have the purpose of detecting an abnormality on the surface of the object, and cannot measure the shape or surface accuracy of the object. .

The one disclosed in Japanese Patent Laid-Open No. 3-295408 is for detecting an uneven defect on a surface to be inspected by utilizing the fact that the diffraction pattern generated by irradiation of a beam differs between a defect and a non-defect. It is not possible to measure the surface shape or surface accuracy. The present invention also relates to a method and apparatus for inspecting irregularities formed on a substantially flat surface to be inspected, and cannot measure the shape or surface accuracy of a spherical surface, aspherical surface, anamorphic surface, or the like.

Among the various conventional examples, the one described in Japanese Patent Application Laid-Open No. 5-180628 is the closest to the invention according to the present application, but since the three-dimensional shape is measured by the triangulation method,
It is difficult to measure wavelength order accurately.

The present invention has been made in view of the above problems of the prior art, and is non-contact, high speed, high precision,
It is an object of the present invention to provide a method and apparatus for measuring internal information such as surface shape, surface accuracy, internal distortion, and fluctuation due to foreign matter. The "surface" referred to here may be a flat surface, a spherical surface, or a special surface such as an anamorphic surface as long as the design value is clear, and the "surface shape" includes an object such as an optical element. It is transmissive, and when transmissivity is measured, it is a major feature that it includes the surface spacing and the refractive index.

[0013]

In order to achieve the above object, the method according to claim 1 is an optical element or the like which has a highly accurate reflective or transmissive surface and whose design value is known. the subject was scanned electromagnetic beam such as a laser, the reflected-bi
The scanning position and scanning speed at the specific position over beam or transmitted beam is measured, the scanning position and scanning speed of the beam in the measurement system including the subject, by taking the difference from the simulation value, the surface of the subject The shape, surface accuracy, or internal information was measured.

A second aspect of the present invention is a method for measuring characteristics when an optical element used in a scanning optical system is used as a subject, and the optical element is irradiated with an electromagnetic wave beam such as a laser in a state substantially equal to that in actual use. scanned, the reflected beam or transmitted Bee
Measuring the scanning position and scanning speed at the specific position of the beam, the beam scanning position and scanning speed in the measurement system including the optical element, by taking the difference from the simulation value, the surface shape of the optical element, a surface The accuracy or internal information was measured.

According to a third aspect of the present invention, in the characteristic measuring method according to the first or second aspect, the characteristics of the measurement system that does not include the object to be examined are obtained in advance, and the influence of processing and installation errors of the measurement system is eliminated. I did it.

According to a fourth aspect of the present invention, there is provided a scanning means for scanning an object such as an optical element with an electromagnetic wave beam such as a laser,
Measuring means for measuring a scanning position and a scanning speed of the reflected beam or the transmitted beam at a specific position, and a spot of the scanning position and the scanning speed of the beam in the measurement system including the subject.
By taking the difference from the Interview configuration value, and a calculating means for measuring the surface shape, surface accuracy or internal information of the subject.

An apparatus according to a fifth aspect is a characteristic measuring apparatus in the case where an optical element used in a scanning optical system is an object to be inspected, and the optical element is scanned with a beam such as a laser in a state substantially equal to actual use. scanning means for, measuring means for measuring the scanning position and scanning speed at the specific position of the reflected beam or transmitted beam, the beam scanning position and scanning speed in the measurement system including the optical element, the difference from the simulation value By so doing, it has a calculating means for measuring the surface shape, surface accuracy or internal information of the optical element.

An apparatus according to a sixth aspect is the characteristic measuring apparatus according to the fourth or fifth aspect, wherein the characteristic measuring apparatus obtains the characteristic of the measuring system not including the object in advance.
The calculation means is characterized by removing the influence of processing and installation errors of the measurement system according to the obtained characteristics.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a characteristic measuring method for an optical element and the like and an apparatus therefor according to the present invention will be described below with reference to the drawings. An embodiment of a characteristic measuring apparatus for an optical element or the like according to the present invention is an apparatus for generating an electromagnetic wave beam such as a laser, and a beam deflection for scanning this beam on a subject having a highly accurate surface such as an optical element. A scanning means including a means, a measuring means for measuring the scanning position and the scanning speed of the electromagnetic beam reflected by the surface of the object or transmitted through the object at a specific position; It has a calculation means and a display means for comparing with a simulation value of a subject and deriving a difference between them.

As the means for generating the electromagnetic wave beam, for example, any of a visible light or infrared light laser, an electron beam, and an X-ray emitting device can be used. As the beam deflecting means, a polygon mirror or a galvano mirror can be used. As the scanning position detecting means, CC
A D (charge coupled device), a position detection type light receiving element, or the like can be used. Further, for the measurement of the scanning speed, a combination of slits or knife edges, photodiodes and the like can be used.

Further, the measuring method shown here is premised on that the design values of all measuring systems including the surface to be measured of the object to be measured are known, and therefore, as in the following various embodiments, Basically, it is possible to measure without using the fθ optical system. Therefore, the object can be measured not only for a laser writing optical system or the like for a scanning optical system, but also for an optical element for a copying machine or a camera.
Hereinafter, various embodiments will be specifically described.

The embodiment shown in FIG. 1 is an example in which the subject is one that reflects on a plane, for example, a plane mirror as an optical element. In FIG. 1, an electromagnetic wave beam 1 such as a laser generated by the electromagnetic wave beam generating means is deflected within a predetermined angle range by a beam deflecting means 2 which constitutes an optical scanning means. A plane mirror 3 having a highly accurate reflecting surface is installed as a subject on the path of the light deflected by the beam deflecting means 2, and a light scanning surface 4 is on the light path reflected by the plane mirror 3. The measuring means 5 including a CCD and a position detection type light receiving element moves along the scanning surface 4 and receives the reflected light from the plane mirror 3. In addition, CC as a measuring means
When a line sensor made of D or the like is used, the line sensor may be fixed along the scanning surface 4 and the relationship between the rotation angle of the beam deflecting means 2 and the light receiving position of the line sensor may be measured.

The measuring means 5 detects the beam reflected from the plane mirror 3 at each specific scanning position, measures the scanning speed at each specific position, and displays the measurement result on an appropriate display means. The measuring device including the beam deflecting means 2, the scanning surface 4, and the measuring means 5 is prepared in advance.
A value is prepared as a simulation value when there is no defect in the flat mirror as the subject, and the difference between the simulation value and the measured value of the flat mirror 3 as the subject is calculated by a calculation means (not shown), and the calculation result is obtained. Is displayed on an appropriate display means. As a result, the surface shape, surface accuracy, or internal information (for example, distortion, fluctuation due to mixing of impurities, etc.) of the flat mirror 3 as the subject can be measured. The above simulation value may be obtained by calculation, or for example, a standard plane mirror having no defect in place of the plane mirror 3 as the subject is installed in the measurement system, and the scanning speed is measured at each specific scanning position in the same manner as above. Then, this measurement result may be used as a simulation value.

According to the embodiment described above, when it is desired to measure or inspect the surface of the subject 3 whose surface shape design value is known, the subject 3 is scanned with the electromagnetic wave beam 1 such as a laser, The characteristic of the subject 3 is measured by measuring the scanning position and the scanning velocity of the reflected beam by the measuring means 5 and taking the difference between the scanning position and the scanning velocity of the beam in the measurement system including the subject 3 with respect to the simulation value. Alternatively, since the quality of the object 3 can be inspected, even if the scanning constant velocity of the entire system for measurement and inspection and the scanning line bending are not corrected with such high accuracy,
There is an advantage that it is possible to measure the processing deviation and the installation deviation from the design value of the subject with high accuracy and speed.

Conventionally, an object is scanned with an electromagnetic wave beam such as a laser and a reflected or transmitted beam is measured,
Although a method of measuring a surface shape or the like has been proposed, it does not take a difference from a simulation value when the object does not have a defect like the above-described embodiment of the present invention, so that the measurement can be performed with high accuracy and speed. And it is difficult to inspect. According to the above-described embodiment of the present invention, in particular, the difference between the scanning speed and the simulation value indicates that the surface shape, surface accuracy, or internal information (distortion,
Since it is differential information (variation due to foreign matter, etc.), it has a characteristic that the sensitivity is higher than that in normal shape measurement.

Next, a second embodiment shown in FIG. 2 will be described. The difference between this embodiment and the first embodiment is that the subject 6 has a light-transmissive highly accurate surface, for example, parallel plate glass, and the light deflected by the beam deflecting means 2 is applied to the subject. 6 is transmitted, and the transmitted light is detected on the scanning surface 4 by the measuring means 5 to measure the transmission characteristic. Also in this embodiment, since the difference between the simulation value in the case of an object having no defect and the actual measurement value of the object 6 is obtained by the measuring means, the scanning of the whole system for measurement and inspection, etc. Even if the speed and the curve of the scanning line are not corrected with high accuracy, the measurement can be performed with high accuracy and speed.

The third embodiment shown in FIG. 3 is a case where the subject measures the transmission characteristics of the wedge prism 7.
The configuration of the measurement system and the measurement method in this case are the same as those in the example shown in FIG. Also in the case of this embodiment, as in the case of the second embodiment, the difference between the simulation value in the case of a defect-free object to be inspected and the actual measurement value of the object to be inspected 7 is obtained by the measuring means, thereby performing Even if the scanning uniform velocity of the whole system for inspection and the scanning line curve are not corrected with such high accuracy, the measurement can be performed with high accuracy and speed.

The fourth embodiment shown in FIG. 4 is a case where the subject measures its reflection characteristics with a concave mirror 8 having a spherical reflecting surface. The configuration of the measurement system and the measurement method in this case are the same as those in the example shown in FIG. Also in the case of this embodiment, as in the first embodiment, the difference between the simulation value in the case of a defect-free subject and the actual measurement value of the concave mirror 8 as the subject is obtained by the measuring means. Thus, even if the scanning constant velocity property of the entire system for measurement and inspection and the curve of the scanning line are not corrected with such high accuracy, the measurement can be performed with high accuracy and speed.

The embodiment shown in FIGS. 1 and 4 can also be applied to the measurement of a reflecting surface formed of a coaxial aspherical surface and the measurement of a reflecting surface formed of an anamorphic surface.

The fifth embodiment shown in FIG. 5 is a case where the subject measures the transmission characteristics of the spherical single lens 9.
The configuration of the measurement system and the measurement method in this case are the same as those in the examples shown in FIGS. 2 and 3, and have the same effects as the examples shown in FIGS. The embodiments shown in FIGS. 2, 3, and 5 can also be applied to the measurement of the transmission characteristic of the coaxial aspherical single lens and the measurement of the transmission characteristic of the anamorphic single lens.

In each of the embodiments described so far, the scanning speed of the deflected beam on the object and the scanning surface differs depending on the deflection angle. Even with such a configuration, since the characteristic of the subject is measured by obtaining the difference between the simulation value and the actually measured value of the subject, the measurement can be performed with high accuracy and speed. However, as shown in FIGS. 1 to 3, the object is a plane reflection surface,
Alternatively, in the case of a flat transmission surface, the measurement accuracy should be improved if the electromagnetic wave beam always enters the subject under the same conditions. Therefore, in the sixth embodiment shown in FIG. 6, when the subject 3 is a plane mirror as in the case of FIG. 1, fθ is between the beam deflecting means 2 and the subject 3.
A lens 10 is arranged so that the scanning speed on the subject 3 and the scanning surface 4 is always constant regardless of the beam deflection angle of the beam deflecting means 2.

As described above, according to the example shown in FIG. 6, since the deflected beam passes through the fθ lens 10, the scanning speeds on the subject 3 and the scanning surface 4 are always constant, so that the simulation value Can be measured with higher accuracy, and the characteristics of the object 3 can be measured with higher accuracy. The measurement system using the fθ lens can be applied not only to the measurement of the reflector but also to the transmission, and not only the plane but also the mirror surface, the aspherical surface,
It can also be applied to measurement of anamorphic surfaces and the like.

In the characteristic measuring method and apparatus according to the present invention, the optical scanning optical system actually used can be used as it is as a measuring system. That is, most of the scanning optical system is used as a measurement system, the remaining part of the optical elements is used as a test object, and the test objects are sequentially replaced to perform measurement and inspection. In this case, the optical element in the part that becomes the measurement system is required to have high accuracy, but if there is a simulation value and measured value only for this part, the correction value is calculated from the difference between them and the measured value of the object is measured. Can also be corrected with the above-mentioned correction value, and therefore it can be said that the optical element forming the measurement system only needs to have a certain degree of accuracy.

The characteristic measuring method and the apparatus therefor according to the present invention can be applied to the case where the object is a synthetic system such as an optical element. The seventh embodiment shown in FIG.
Is an example in the case of being constituted by a parallel-plane transmission body 11a and a concave mirror 11b having a mirror surface or an aspherical reflection surface. The configuration of the measurement system and the measurement method are substantially the same as the examples shown in FIGS. 1 and 4, and the parallel-plane transmissive body 11a is used.
It is possible to measure transmission and reflection characteristics of the subject 11 in which the concave mirror 11b and the concave mirror 11b are combined.

The eighth embodiment shown in FIG. 8 is the subject 1
2 is an example in the case of being configured by a plano-convex lens 12a, a meniscus convex lens 12b, and an anamorphic lens 12c. The configuration of the measurement system and the measurement method are shown in FIGS.
This is substantially the same as the example shown in FIG.
It is possible to measure the transmission characteristics of the subject 12 in which a, 12b, and 12c are combined.

FIG. 9 shows a simulation value of the scanning position when a coaxial aspherical concave mirror is measured as the object in the fourth embodiment shown in FIG. 4 and the actual measurement values (raw data) of three samples. ), And the image height (m
m) is the scanning position (mm) on the vertical axis. The characteristics of each sample can be measured by comparing the simulation value with the measured value, but it is difficult to understand the difference between the three samples as it is. Therefore, FIG. 10 shows the difference between the measured value of each material and the simulation value. Figure 1
According to 0, the difference between the actual measurement value of each material and the simulation value is clear. Incidentally, it is quantitatively measured that the sample 1 is entirely tilted and that the samples 2 and 3 are twisted.

11 and 12 show the scanning speed of the same measurement using the coaxial aspherical concave mirror as an object, and FIG. 11 compares the simulation value with the measured value of each material. 12 shows the difference between the actual measurement value of each material and the simulation value. Also in this case, in FIG. 12 in which the simulation value is subtracted from the actual measurement value, the processing error of the shape and surface accuracy is quantitatively shown, and the difference between the three samples is also clearly shown.

[0038]

According to the first and fourth aspects of the invention, an object having a highly accurate reflective or transmissive surface and a design value of the surface being known is scanned by an electromagnetic wave beam such as a laser. and, the reflected beam or by measuring the <br/> scanning position and scanning speed at the specific position of the transmitted beam, the beam scanning position and scanning speed in the measurement system including the object, simulation Reshi <br/> tio emission value By taking the difference with respect to the surface shape of the subject ,
Since the surface accuracy or internal information is measured,
Even if the scanning constant velocity of the entire system for inspection and the scan line bending are not corrected with such high accuracy, deviation from the design value of the subject, unevenness, inclination, twist, etc. can be obtained with high accuracy and speed. You can In particular, the difference between the simulation rate <br/> retardation value of the scanning speed measurement surface shape and surface accuracy or the internal information (distortion,
Since it is differential information (variation due to impurities, etc.), it has a characteristic that the sensitivity is higher than that in normal shape measurement.

According to the second and fifth aspects of the present invention, since the optical element used in the scanning optical system is measured in a state substantially equal to that in actual use, the measurement result of the optical element and the practical whole system are measured. There is an advantage that the correspondence with the performance becomes clear and the evaluation is accurate and easy.

According to the third and sixth aspects of the invention, since the characteristic values of the measurement system not including the subject are obtained in advance, it is possible to eliminate the influence of processing and installation errors of the measurement system. The measurement accuracy can be further improved.

[Brief description of drawings]

FIG. 1 is an optical layout diagram showing an embodiment of a characteristic measuring method for an optical element and the like and an apparatus therefor according to the present invention.

FIG. 2 is an optical layout diagram showing another embodiment of a characteristic measuring method for an optical element and the like and an apparatus therefor according to the present invention.

FIG. 3 is an optical layout diagram showing still another embodiment of a characteristic measuring method for an optical element and the like and an apparatus therefor according to the present invention.

FIG. 4 is an optical layout diagram showing still another embodiment of a characteristic measuring method for an optical element and the like and an apparatus therefor according to the present invention.

FIG. 5 is an optical layout diagram showing still another embodiment of a characteristic measuring method for an optical element and the like and an apparatus therefor according to the present invention.

FIG. 6 is an optical layout diagram showing still another embodiment of a characteristic measuring method for an optical element and the like and an apparatus therefor according to the present invention.

FIG. 7 is an optical layout diagram showing still another embodiment of a characteristic measuring method for an optical element and the like and an apparatus therefor according to the present invention.

FIG. 8 is an optical layout diagram showing still another embodiment of a characteristic measuring method for an optical element and the like and an apparatus therefor according to the present invention.

FIG. 9 is a graph showing a comparison between an actual measurement value of a scanning position and a simulation value when a coaxial aspherical concave mirror is measured in the embodiment shown in FIG.

FIG. 10 is a graph showing the difference between the actual measurement value and the simulation value for the scanning position of the coaxial aspherical concave mirror.

FIG. 11 is a graph showing a comparison between the simulation value and the actual measurement value of each material regarding the scanning speed of the coaxial aspherical concave mirror.

FIG. 12 is a graph showing the difference between the actual measurement value and the simulation value for the scanning speed of the coaxial aspherical concave mirror.

[Explanation of symbols]

1 Electromagnetic beam 2 Deflection means constituting scanning means 3 subject 5 Measuring means 7 subject 8 subject 9 subject 11 subject 12 subject

Continuation of the front page (56) Reference JP-A-4-5536 (JP, A) JP-A-51-72459 (JP, A) JP-A-60-95313 (JP, A) JP-A-1-176929 (JP , A) Japanese Unexamined Patent Publication No. 2-77608 (JP, A) SAIKAI 57-175035 (JP, U) Tokumei HEI 3-501058 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB) Name) G01M 11/00-11/08 G01B 11/00-11/30 G01N 21/84-21/958 G02B 26/10

Claims (6)

(57) [Claims] 1. A specific position of a reflected beam or a transmitted beam by scanning an object such as an optical element having a highly accurate reflective or transmissive surface whose design value is known with an electromagnetic wave beam such as a laser. measuring the scanning position and scanning speed, the scanning position and scanning speed of the beam in the measurement system including the subject, by taking the difference from the simulation value, the surface shape of the object, the surface accuracy or the internal information A method for measuring characteristics of an optical element or the like, characterized by measuring. 2. An optical element having a highly reflective or transmissive surface whose design value is known and which is used in a scanning optical system is scanned with an electromagnetic wave beam such as a laser in a state substantially equal to that in actual use. , Specific position of reflected beam or transmitted beam
Measuring the scanning position and the scanning speed in the position, of the scanning position and the scanning speed of the beam in the measurement system including the optical element,
By taking the difference from the simulation value, characteristic measuring method, such as an optical element characterized by measuring the surface shape, surface accuracy or the internal information of the optical element. 3. The optical element according to claim 1, wherein the characteristics of a measurement system that does not include an object to be measured are obtained in advance by the measurement method, and effects of processing and installation errors of the measurement system are removed. Method of measuring characteristics such as. 4. A scanning means for scanning an object such as an optical element with an electromagnetic wave beam such as a laser, a measuring means for measuring a scanning position and a scanning speed of a reflected beam or a transmitted beam at a specific position, and the object. the beam scanning position and scanning speed in the measurement system including by taking the difference from the simulation value, the subject of the surface shape, comprising a calculation means for measuring the surface accuracy or internal information, such as an optical element Characteristic measuring device. 5. A characteristic measuring device for an optical element used for a scanning optical system, which has a highly accurate reflective or transmissive surface, a design value of which is known, and the optical element is abbreviated as “actual use”. Scanning means for scanning with an electromagnetic wave beam such as a laser in the same state, and a specific position of a reflected beam or a transmitted beam
Measuring means for measuring the scanning position and scanning speed, the beam scanning position and scanning speed in the measurement system including the optical element, by taking the difference from the simulation value, the surface shape, surface accuracy of the optical element Alternatively, a characteristic measuring device such as an optical element having a calculating means for measuring internal information. 6. The characteristic measuring device obtains the characteristic of a measuring system which does not include the object in advance, and the calculating means removes the influence of processing and installation error of the measuring system according to the obtained characteristic. 6. The characteristic measuring device for an optical element or the like according to claim 4 or 5.